fix build error

5 files changed, 3310 insertions, 0 deletions

diff --git a/third_party/protobuf-lite/google/protobuf/any.h b/third_party/protobuf-lite/google/protobuf/any.h
new file mode 100644
index 0000000..59dd50c
--- /dev/null
+++ b/third_party/protobuf-lite/google/protobuf/any.h
@@ -0,0 +1,149 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef GOOGLE_PROTOBUF_ANY_H__
+#define GOOGLE_PROTOBUF_ANY_H__
+
+#include <string>
+
+#include <google/protobuf/stubs/common.h>
+#include <google/protobuf/arenastring.h>
+#include <google/protobuf/message_lite.h>
+
+#include <google/protobuf/port_def.inc>
+
+namespace google {
+namespace protobuf {
+
+class FieldDescriptor;
+class Message;
+
+namespace internal {
+
+extern const char kAnyFullTypeName[];          // "google.protobuf.Any".
+extern const char kTypeGoogleApisComPrefix[];  // "type.googleapis.com/".
+extern const char kTypeGoogleProdComPrefix[];  // "type.googleprod.com/".
+
+std::string GetTypeUrl(StringPiece message_name,
+                       StringPiece type_url_prefix);
+
+// Helper class used to implement google::protobuf::Any.
+class PROTOBUF_EXPORT AnyMetadata {
+  typedef ArenaStringPtr UrlType;
+  typedef ArenaStringPtr ValueType;
+ public:
+  // AnyMetadata does not take ownership of "type_url" and "value".
+  AnyMetadata(UrlType* type_url, ValueType* value);
+
+  // Packs a message using the default type URL prefix: "type.googleapis.com".
+  // The resulted type URL will be "type.googleapis.com/<message_full_name>".
+  template <typename T>
+  void PackFrom(const T& message) {
+    InternalPackFrom(message, kTypeGoogleApisComPrefix, T::FullMessageName());
+  }
+
+  void PackFrom(const Message& message);
+
+  // Packs a message using the given type URL prefix. The type URL will be
+  // constructed by concatenating the message type's full name to the prefix
+  // with an optional "/" separator if the prefix doesn't already end with "/".
+  // For example, both PackFrom(message, "type.googleapis.com") and
+  // PackFrom(message, "type.googleapis.com/") yield the same result type
+  // URL: "type.googleapis.com/<message_full_name>".
+  template <typename T>
+  void PackFrom(const T& message, StringPiece type_url_prefix) {
+    InternalPackFrom(message, type_url_prefix, T::FullMessageName());
+  }
+
+  void PackFrom(const Message& message, const std::string& type_url_prefix);
+
+  // Unpacks the payload into the given message. Returns false if the message's
+  // type doesn't match the type specified in the type URL (i.e., the full
+  // name after the last "/" of the type URL doesn't match the message's actual
+  // full name) or parsing the payload has failed.
+  template <typename T>
+  bool UnpackTo(T* message) const {
+    return InternalUnpackTo(T::FullMessageName(), message);
+  }
+
+  bool UnpackTo(Message* message) const;
+
+  // Checks whether the type specified in the type URL matches the given type.
+  // A type is considered matching if its full name matches the full name after
+  // the last "/" in the type URL.
+  template <typename T>
+  bool Is() const {
+    return InternalIs(T::FullMessageName());
+  }
+
+ private:
+  void InternalPackFrom(const MessageLite& message,
+                        StringPiece type_url_prefix,
+                        StringPiece type_name);
+  bool InternalUnpackTo(StringPiece type_name,
+                        MessageLite* message) const;
+  bool InternalIs(StringPiece type_name) const;
+
+  UrlType* type_url_;
+  ValueType* value_;
+
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(AnyMetadata);
+};
+
+// Get the proto type name from Any::type_url value. For example, passing
+// "type.googleapis.com/rpc.QueryOrigin" will return "rpc.QueryOrigin" in
+// *full_type_name. Returns false if the type_url does not have a "/"
+// in the type url separating the full type name.
+//
+// NOTE: this function is available publicly as:
+//   google::protobuf::Any()  // static method on the generated message type.
+bool ParseAnyTypeUrl(const std::string& type_url, std::string* full_type_name);
+
+// Get the proto type name and prefix from Any::type_url value. For example,
+// passing "type.googleapis.com/rpc.QueryOrigin" will return
+// "type.googleapis.com/" in *url_prefix and "rpc.QueryOrigin" in
+// *full_type_name. Returns false if the type_url does not have a "/" in the
+// type url separating the full type name.
+bool ParseAnyTypeUrl(const std::string& type_url, std::string* url_prefix,
+                     std::string* full_type_name);
+
+// See if message is of type google.protobuf.Any, if so, return the descriptors
+// for "type_url" and "value" fields.
+bool GetAnyFieldDescriptors(const Message& message,
+                            const FieldDescriptor** type_url_field,
+                            const FieldDescriptor** value_field);
+
+}  // namespace internal
+}  // namespace protobuf
+}  // namespace google
+
+#include <google/protobuf/port_undef.inc>
+
+#endif  // GOOGLE_PROTOBUF_ANY_H__
diff --git a/third_party/protobuf-lite/google/protobuf/descriptor.h b/third_party/protobuf-lite/google/protobuf/descriptor.h
new file mode 100644
index 0000000..08b03a8
--- /dev/null
+++ b/third_party/protobuf-lite/google/protobuf/descriptor.h
@@ -0,0 +1,2315 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: kenton@google.com (Kenton Varda)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+//
+// This file contains classes which describe a type of protocol message.
+// You can use a message's descriptor to learn at runtime what fields
+// it contains and what the types of those fields are.  The Message
+// interface also allows you to dynamically access and modify individual
+// fields by passing the FieldDescriptor of the field you are interested
+// in.
+//
+// Most users will not care about descriptors, because they will write
+// code specific to certain protocol types and will simply use the classes
+// generated by the protocol compiler directly.  Advanced users who want
+// to operate on arbitrary types (not known at compile time) may want to
+// read descriptors in order to learn about the contents of a message.
+// A very small number of users will want to construct their own
+// Descriptors, either because they are implementing Message manually or
+// because they are writing something like the protocol compiler.
+//
+// For an example of how you might use descriptors, see the code example
+// at the top of message.h.
+
+#ifndef GOOGLE_PROTOBUF_DESCRIPTOR_H__
+#define GOOGLE_PROTOBUF_DESCRIPTOR_H__
+
+#include <map>
+#include <memory>
+#include <set>
+#include <string>
+#include <vector>
+
+#include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/mutex.h>
+#include <google/protobuf/stubs/once.h>
+#include <google/protobuf/port_def.inc>
+
+// TYPE_BOOL is defined in the MacOS's ConditionalMacros.h.
+#ifdef TYPE_BOOL
+#undef TYPE_BOOL
+#endif  // TYPE_BOOL
+
+#ifdef SWIG
+#define PROTOBUF_EXPORT
+#endif
+
+
+namespace google {
+namespace protobuf {
+
+// Defined in this file.
+class Descriptor;
+class FieldDescriptor;
+class OneofDescriptor;
+class EnumDescriptor;
+class EnumValueDescriptor;
+class ServiceDescriptor;
+class MethodDescriptor;
+class FileDescriptor;
+class DescriptorDatabase;
+class DescriptorPool;
+
+// Defined in descriptor.proto
+class DescriptorProto;
+class DescriptorProto_ExtensionRange;
+class FieldDescriptorProto;
+class OneofDescriptorProto;
+class EnumDescriptorProto;
+class EnumValueDescriptorProto;
+class ServiceDescriptorProto;
+class MethodDescriptorProto;
+class FileDescriptorProto;
+class MessageOptions;
+class FieldOptions;
+class OneofOptions;
+class EnumOptions;
+class EnumValueOptions;
+class ExtensionRangeOptions;
+class ServiceOptions;
+class MethodOptions;
+class FileOptions;
+class UninterpretedOption;
+class SourceCodeInfo;
+
+// Defined in message.h
+class Message;
+class Reflection;
+
+// Defined in descriptor.cc
+class DescriptorBuilder;
+class FileDescriptorTables;
+struct Symbol;
+
+// Defined in unknown_field_set.h.
+class UnknownField;
+
+// Defined in command_line_interface.cc
+namespace compiler {
+class CommandLineInterface;
+namespace cpp {
+// Defined in helpers.h
+class Formatter;
+}  // namespace cpp
+}  // namespace compiler
+
+namespace descriptor_unittest {
+class DescriptorTest;
+}  // namespace descriptor_unittest
+
+// Defined in printer.h
+namespace io {
+class Printer;
+}  // namespace io
+
+// NB, all indices are zero-based.
+struct SourceLocation {
+  int start_line;
+  int end_line;
+  int start_column;
+  int end_column;
+
+  // Doc comments found at the source location.
+  // See the comments in SourceCodeInfo.Location (descriptor.proto) for details.
+  std::string leading_comments;
+  std::string trailing_comments;
+  std::vector<std::string> leading_detached_comments;
+};
+
+// Options when generating machine-parsable output from a descriptor with
+// DebugString().
+struct DebugStringOptions {
+  // include original user comments as recorded in SourceLocation entries. N.B.
+  // that this must be |false| by default: several other pieces of code (for
+  // example, the C++ code generation for fields in the proto compiler) rely on
+  // DebugString() output being unobstructed by user comments.
+  bool include_comments;
+  // If true, elide the braced body in the debug string.
+  bool elide_group_body;
+  bool elide_oneof_body;
+
+  DebugStringOptions()
+      : include_comments(false),
+        elide_group_body(false),
+        elide_oneof_body(false) {
+  }
+};
+
+// A class to handle the simplest cases of a lazily linked descriptor
+// for a message type that isn't built at the time of cross linking,
+// which is needed when a pool has lazily_build_dependencies_ set.
+// Must be instantiated as mutable in a descriptor.
+namespace internal {
+class PROTOBUF_EXPORT LazyDescriptor {
+ public:
+  // Init function to be called at init time of a descriptor containing
+  // a LazyDescriptor.
+  void Init() {
+    descriptor_ = nullptr;
+    name_ = nullptr;
+    once_ = nullptr;
+    file_ = nullptr;
+  }
+
+  // Sets the value of the descriptor if it is known during the descriptor
+  // building process. Not thread safe, should only be called during the
+  // descriptor build process. Should not be called after SetLazy has been
+  // called.
+  void Set(const Descriptor* descriptor);
+
+  // Sets the information needed to lazily cross link the descriptor at a later
+  // time, SetLazy is not thread safe, should be called only once at descriptor
+  // build time if the symbol wasn't found and building of the file containing
+  // that type is delayed because lazily_build_dependencies_ is set on the pool.
+  // Should not be called after Set() has been called.
+  void SetLazy(const std::string& name, const FileDescriptor* file);
+
+  // Returns the current value of the descriptor, thread-safe. If SetLazy(...)
+  // has been called, will do a one-time cross link of the type specified,
+  // building the descriptor file that contains the type if necessary.
+  inline const Descriptor* Get() {
+    Once();
+    return descriptor_;
+  }
+
+ private:
+  static void OnceStatic(LazyDescriptor* lazy);
+  void OnceInternal();
+  void Once();
+
+  const Descriptor* descriptor_;
+  const std::string* name_;
+  internal::once_flag* once_;
+  const FileDescriptor* file_;
+};
+}  // namespace internal
+
+// Describes a type of protocol message, or a particular group within a
+// message.  To obtain the Descriptor for a given message object, call
+// Message::GetDescriptor().  Generated message classes also have a
+// static method called descriptor() which returns the type's descriptor.
+// Use DescriptorPool to construct your own descriptors.
+class PROTOBUF_EXPORT Descriptor {
+ public:
+  typedef DescriptorProto Proto;
+
+  // The name of the message type, not including its scope.
+  const std::string& name() const;
+
+  // The fully-qualified name of the message type, scope delimited by
+  // periods.  For example, message type "Foo" which is declared in package
+  // "bar" has full name "bar.Foo".  If a type "Baz" is nested within
+  // Foo, Baz's full_name is "bar.Foo.Baz".  To get only the part that
+  // comes after the last '.', use name().
+  const std::string& full_name() const;
+
+  // Index of this descriptor within the file or containing type's message
+  // type array.
+  int index() const;
+
+  // The .proto file in which this message type was defined.  Never nullptr.
+  const FileDescriptor* file() const;
+
+  // If this Descriptor describes a nested type, this returns the type
+  // in which it is nested.  Otherwise, returns nullptr.
+  const Descriptor* containing_type() const;
+
+  // Get options for this message type.  These are specified in the .proto file
+  // by placing lines like "option foo = 1234;" in the message definition.
+  // Allowed options are defined by MessageOptions in descriptor.proto, and any
+  // available extensions of that message.
+  const MessageOptions& options() const;
+
+  // Write the contents of this Descriptor into the given DescriptorProto.
+  // The target DescriptorProto must be clear before calling this; if it
+  // isn't, the result may be garbage.
+  void CopyTo(DescriptorProto* proto) const;
+
+  // Write the contents of this descriptor in a human-readable form. Output
+  // will be suitable for re-parsing.
+  std::string DebugString() const;
+
+  // Similar to DebugString(), but additionally takes options (e.g.,
+  // include original user comments in output).
+  std::string DebugStringWithOptions(const DebugStringOptions& options) const;
+
+  // Returns true if this is a placeholder for an unknown type. This will
+  // only be the case if this descriptor comes from a DescriptorPool
+  // with AllowUnknownDependencies() set.
+  bool is_placeholder() const;
+
+  enum WellKnownType {
+    WELLKNOWNTYPE_UNSPECIFIED,  // Not a well-known type.
+
+    // Wrapper types.
+    WELLKNOWNTYPE_DOUBLEVALUE,  // google.protobuf.DoubleValue
+    WELLKNOWNTYPE_FLOATVALUE,   // google.protobuf.FloatValue
+    WELLKNOWNTYPE_INT64VALUE,   // google.protobuf.Int64Value
+    WELLKNOWNTYPE_UINT64VALUE,  // google.protobuf.UInt64Value
+    WELLKNOWNTYPE_INT32VALUE,   // google.protobuf.Int32Value
+    WELLKNOWNTYPE_UINT32VALUE,  // google.protobuf.UInt32Value
+    WELLKNOWNTYPE_STRINGVALUE,  // google.protobuf.StringValue
+    WELLKNOWNTYPE_BYTESVALUE,   // google.protobuf.BytesValue
+    WELLKNOWNTYPE_BOOLVALUE,    // google.protobuf.BoolValue
+
+    // Other well known types.
+    WELLKNOWNTYPE_ANY,        // google.protobuf.Any
+    WELLKNOWNTYPE_FIELDMASK,  // google.protobuf.FieldMask
+    WELLKNOWNTYPE_DURATION,   // google.protobuf.Duration
+    WELLKNOWNTYPE_TIMESTAMP,  // google.protobuf.Timestamp
+    WELLKNOWNTYPE_VALUE,      // google.protobuf.Value
+    WELLKNOWNTYPE_LISTVALUE,  // google.protobuf.ListValue
+    WELLKNOWNTYPE_STRUCT,     // google.protobuf.Struct
+
+    // New well-known types may be added in the future.
+    // Please make sure any switch() statements have a 'default' case.
+    __WELLKNOWNTYPE__DO_NOT_USE__ADD_DEFAULT_INSTEAD__,
+  };
+
+  WellKnownType well_known_type() const;
+
+  // Field stuff -----------------------------------------------------
+
+  // The number of fields in this message type.
+  int field_count() const;
+  // Gets a field by index, where 0 <= index < field_count().
+  // These are returned in the order they were defined in the .proto file.
+  const FieldDescriptor* field(int index) const;
+
+  // Looks up a field by declared tag number.  Returns nullptr if no such field
+  // exists.
+  const FieldDescriptor* FindFieldByNumber(int number) const;
+  // Looks up a field by name.  Returns nullptr if no such field exists.
+  const FieldDescriptor* FindFieldByName(const std::string& name) const;
+
+  // Looks up a field by lowercased name (as returned by lowercase_name()).
+  // This lookup may be ambiguous if multiple field names differ only by case,
+  // in which case the field returned is chosen arbitrarily from the matches.
+  const FieldDescriptor* FindFieldByLowercaseName(
+      const std::string& lowercase_name) const;
+
+  // Looks up a field by camel-case name (as returned by camelcase_name()).
+  // This lookup may be ambiguous if multiple field names differ in a way that
+  // leads them to have identical camel-case names, in which case the field
+  // returned is chosen arbitrarily from the matches.
+  const FieldDescriptor* FindFieldByCamelcaseName(
+      const std::string& camelcase_name) const;
+
+  // The number of oneofs in this message type.
+  int oneof_decl_count() const;
+  // The number of oneofs in this message type, excluding synthetic oneofs.
+  // Real oneofs always come first, so iterating up to real_oneof_decl_cout()
+  // will yield all real oneofs.
+  int real_oneof_decl_count() const;
+  // Get a oneof by index, where 0 <= index < oneof_decl_count().
+  // These are returned in the order they were defined in the .proto file.
+  const OneofDescriptor* oneof_decl(int index) const;
+
+  // Looks up a oneof by name.  Returns nullptr if no such oneof exists.
+  const OneofDescriptor* FindOneofByName(const std::string& name) const;
+
+  // Nested type stuff -----------------------------------------------
+
+  // The number of nested types in this message type.
+  int nested_type_count() const;
+  // Gets a nested type by index, where 0 <= index < nested_type_count().
+  // These are returned in the order they were defined in the .proto file.
+  const Descriptor* nested_type(int index) const;
+
+  // Looks up a nested type by name.  Returns nullptr if no such nested type
+  // exists.
+  const Descriptor* FindNestedTypeByName(const std::string& name) const;
+
+  // Enum stuff ------------------------------------------------------
+
+  // The number of enum types in this message type.
+  int enum_type_count() const;
+  // Gets an enum type by index, where 0 <= index < enum_type_count().
+  // These are returned in the order they were defined in the .proto file.
+  const EnumDescriptor* enum_type(int index) const;
+
+  // Looks up an enum type by name.  Returns nullptr if no such enum type
+  // exists.
+  const EnumDescriptor* FindEnumTypeByName(const std::string& name) const;
+
+  // Looks up an enum value by name, among all enum types in this message.
+  // Returns nullptr if no such value exists.
+  const EnumValueDescriptor* FindEnumValueByName(const std::string& name) const;
+
+  // Extensions ------------------------------------------------------
+
+  // A range of field numbers which are designated for third-party
+  // extensions.
+  struct ExtensionRange {
+    typedef DescriptorProto_ExtensionRange Proto;
+
+    typedef ExtensionRangeOptions OptionsType;
+
+    // See Descriptor::CopyTo().
+    void CopyTo(DescriptorProto_ExtensionRange* proto) const;
+
+    int start;  // inclusive
+    int end;    // exclusive
+
+    const ExtensionRangeOptions* options_;
+  };
+
+  // The number of extension ranges in this message type.
+  int extension_range_count() const;
+  // Gets an extension range by index, where 0 <= index <
+  // extension_range_count(). These are returned in the order they were defined
+  // in the .proto file.
+  const ExtensionRange* extension_range(int index) const;
+
+  // Returns true if the number is in one of the extension ranges.
+  bool IsExtensionNumber(int number) const;
+
+  // Returns nullptr if no extension range contains the given number.
+  const ExtensionRange* FindExtensionRangeContainingNumber(int number) const;
+
+  // The number of extensions defined nested within this message type's scope.
+  // See doc:
+  // https://developers.google.com/protocol-buffers/docs/proto#nested-extensions
+  //
+  // Note that the extensions may be extending *other* messages.
+  //
+  // For example:
+  // message M1 {
+  //   extensions 1 to max;
+  // }
+  //
+  // message M2 {
+  //   extend M1 {
+  //     optional int32 foo = 1;
+  //   }
+  // }
+  //
+  // In this case,
+  // DescriptorPool::generated_pool()
+  //     ->FindMessageTypeByName("M2")
+  //     ->extension(0)
+  // will return "foo", even though "foo" is an extension of M1.
+  // To find all known extensions of a given message, instead use
+  // DescriptorPool::FindAllExtensions.
+  int extension_count() const;
+  // Get an extension by index, where 0 <= index < extension_count().
+  // These are returned in the order they were defined in the .proto file.
+  const FieldDescriptor* extension(int index) const;
+
+  // Looks up a named extension (which extends some *other* message type)
+  // defined within this message type's scope.
+  const FieldDescriptor* FindExtensionByName(const std::string& name) const;
+
+  // Similar to FindFieldByLowercaseName(), but finds extensions defined within
+  // this message type's scope.
+  const FieldDescriptor* FindExtensionByLowercaseName(
+      const std::string& name) const;
+
+  // Similar to FindFieldByCamelcaseName(), but finds extensions defined within
+  // this message type's scope.
+  const FieldDescriptor* FindExtensionByCamelcaseName(
+      const std::string& name) const;
+
+  // Reserved fields -------------------------------------------------
+
+  // A range of reserved field numbers.
+  struct ReservedRange {
+    int start;  // inclusive
+    int end;    // exclusive
+  };
+
+  // The number of reserved ranges in this message type.
+  int reserved_range_count() const;
+  // Gets an reserved range by index, where 0 <= index <
+  // reserved_range_count(). These are returned in the order they were defined
+  // in the .proto file.
+  const ReservedRange* reserved_range(int index) const;
+
+  // Returns true if the number is in one of the reserved ranges.
+  bool IsReservedNumber(int number) const;
+
+  // Returns nullptr if no reserved range contains the given number.
+  const ReservedRange* FindReservedRangeContainingNumber(int number) const;
+
+  // The number of reserved field names in this message type.
+  int reserved_name_count() const;
+
+  // Gets a reserved name by index, where 0 <= index < reserved_name_count().
+  const std::string& reserved_name(int index) const;
+
+  // Returns true if the field name is reserved.
+  bool IsReservedName(const std::string& name) const;
+
+  // Source Location ---------------------------------------------------
+
+  // Updates |*out_location| to the source location of the complete
+  // extent of this message declaration.  Returns false and leaves
+  // |*out_location| unchanged iff location information was not available.
+  bool GetSourceLocation(SourceLocation* out_location) const;
+
+  // Maps --------------------------------------------------------------
+
+  // Returns the FieldDescriptor for the "key" field. If this isn't a map entry
+  // field, returns nullptr.
+  const FieldDescriptor* map_key() const;
+
+  // Returns the FieldDescriptor for the "value" field. If this isn't a map
+  // entry field, returns nullptr.
+  const FieldDescriptor* map_value() const;
+
+ private:
+  typedef MessageOptions OptionsType;
+
+  // Allows tests to test CopyTo(proto, true).
+  friend class descriptor_unittest::DescriptorTest;
+
+  // Allows access to GetLocationPath for annotations.
+  friend class io::Printer;
+  friend class compiler::cpp::Formatter;
+
+  // Fill the json_name field of FieldDescriptorProto.
+  void CopyJsonNameTo(DescriptorProto* proto) const;
+
+  // Internal version of DebugString; controls the level of indenting for
+  // correct depth. Takes |options| to control debug-string options, and
+  // |include_opening_clause| to indicate whether the "message ... " part of the
+  // clause has already been generated (this varies depending on context).
+  void DebugString(int depth, std::string* contents,
+                   const DebugStringOptions& options,
+                   bool include_opening_clause) const;
+
+  // Walks up the descriptor tree to generate the source location path
+  // to this descriptor from the file root.
+  void GetLocationPath(std::vector<int>* output) const;
+
+  const std::string* name_;
+  const std::string* full_name_;
+  const FileDescriptor* file_;
+  const Descriptor* containing_type_;
+  const MessageOptions* options_;
+
+  // These arrays are separated from their sizes to minimize padding on 64-bit.
+  FieldDescriptor* fields_;
+  OneofDescriptor* oneof_decls_;
+  Descriptor* nested_types_;
+  EnumDescriptor* enum_types_;
+  ExtensionRange* extension_ranges_;
+  FieldDescriptor* extensions_;
+  ReservedRange* reserved_ranges_;
+  const std::string** reserved_names_;
+
+  int field_count_;
+  int oneof_decl_count_;
+  int real_oneof_decl_count_;
+  int nested_type_count_;
+  int enum_type_count_;
+  int extension_range_count_;
+  int extension_count_;
+  int reserved_range_count_;
+  int reserved_name_count_;
+
+  // True if this is a placeholder for an unknown type.
+  bool is_placeholder_;
+  // True if this is a placeholder and the type name wasn't fully-qualified.
+  bool is_unqualified_placeholder_;
+  // Well known type.  Stored as char to conserve space.
+  char well_known_type_;
+
+  // IMPORTANT:  If you add a new field, make sure to search for all instances
+  // of Allocate<Descriptor>() and AllocateArray<Descriptor>() in descriptor.cc
+  // and update them to initialize the field.
+
+  // Must be constructed using DescriptorPool.
+  Descriptor() {}
+  friend class DescriptorBuilder;
+  friend class DescriptorPool;
+  friend class EnumDescriptor;
+  friend class FieldDescriptor;
+  friend class OneofDescriptor;
+  friend class MethodDescriptor;
+  friend class FileDescriptor;
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Descriptor);
+};
+
+
+// Describes a single field of a message.  To get the descriptor for a given
+// field, first get the Descriptor for the message in which it is defined,
+// then call Descriptor::FindFieldByName().  To get a FieldDescriptor for
+// an extension, do one of the following:
+// - Get the Descriptor or FileDescriptor for its containing scope, then
+//   call Descriptor::FindExtensionByName() or
+//   FileDescriptor::FindExtensionByName().
+// - Given a DescriptorPool, call DescriptorPool::FindExtensionByNumber() or
+//   DescriptorPool::FindExtensionByPrintableName().
+// Use DescriptorPool to construct your own descriptors.
+class PROTOBUF_EXPORT FieldDescriptor {
+ public:
+  typedef FieldDescriptorProto Proto;
+
+  // Identifies a field type.  0 is reserved for errors.  The order is weird
+  // for historical reasons.  Types 12 and up are new in proto2.
+  enum Type {
+    TYPE_DOUBLE = 1,    // double, exactly eight bytes on the wire.
+    TYPE_FLOAT = 2,     // float, exactly four bytes on the wire.
+    TYPE_INT64 = 3,     // int64, varint on the wire.  Negative numbers
+                        // take 10 bytes.  Use TYPE_SINT64 if negative
+                        // values are likely.
+    TYPE_UINT64 = 4,    // uint64, varint on the wire.
+    TYPE_INT32 = 5,     // int32, varint on the wire.  Negative numbers
+                        // take 10 bytes.  Use TYPE_SINT32 if negative
+                        // values are likely.
+    TYPE_FIXED64 = 6,   // uint64, exactly eight bytes on the wire.
+    TYPE_FIXED32 = 7,   // uint32, exactly four bytes on the wire.
+    TYPE_BOOL = 8,      // bool, varint on the wire.
+    TYPE_STRING = 9,    // UTF-8 text.
+    TYPE_GROUP = 10,    // Tag-delimited message.  Deprecated.
+    TYPE_MESSAGE = 11,  // Length-delimited message.
+
+    TYPE_BYTES = 12,     // Arbitrary byte array.
+    TYPE_UINT32 = 13,    // uint32, varint on the wire
+    TYPE_ENUM = 14,      // Enum, varint on the wire
+    TYPE_SFIXED32 = 15,  // int32, exactly four bytes on the wire
+    TYPE_SFIXED64 = 16,  // int64, exactly eight bytes on the wire
+    TYPE_SINT32 = 17,    // int32, ZigZag-encoded varint on the wire
+    TYPE_SINT64 = 18,    // int64, ZigZag-encoded varint on the wire
+
+    MAX_TYPE = 18,  // Constant useful for defining lookup tables
+                    // indexed by Type.
+  };
+
+  // Specifies the C++ data type used to represent the field.  There is a
+  // fixed mapping from Type to CppType where each Type maps to exactly one
+  // CppType.  0 is reserved for errors.
+  enum CppType {
+    CPPTYPE_INT32 = 1,     // TYPE_INT32, TYPE_SINT32, TYPE_SFIXED32
+    CPPTYPE_INT64 = 2,     // TYPE_INT64, TYPE_SINT64, TYPE_SFIXED64
+    CPPTYPE_UINT32 = 3,    // TYPE_UINT32, TYPE_FIXED32
+    CPPTYPE_UINT64 = 4,    // TYPE_UINT64, TYPE_FIXED64
+    CPPTYPE_DOUBLE = 5,    // TYPE_DOUBLE
+    CPPTYPE_FLOAT = 6,     // TYPE_FLOAT
+    CPPTYPE_BOOL = 7,      // TYPE_BOOL
+    CPPTYPE_ENUM = 8,      // TYPE_ENUM
+    CPPTYPE_STRING = 9,    // TYPE_STRING, TYPE_BYTES
+    CPPTYPE_MESSAGE = 10,  // TYPE_MESSAGE, TYPE_GROUP
+
+    MAX_CPPTYPE = 10,  // Constant useful for defining lookup tables
+                       // indexed by CppType.
+  };
+
+  // Identifies whether the field is optional, required, or repeated.  0 is
+  // reserved for errors.
+  enum Label {
+    LABEL_OPTIONAL = 1,  // optional
+    LABEL_REQUIRED = 2,  // required
+    LABEL_REPEATED = 3,  // repeated
+
+    MAX_LABEL = 3,  // Constant useful for defining lookup tables
+                    // indexed by Label.
+  };
+
+  // Valid field numbers are positive integers up to kMaxNumber.
+  static const int kMaxNumber = (1 << 29) - 1;
+
+  // First field number reserved for the protocol buffer library implementation.
+  // Users may not declare fields that use reserved numbers.
+  static const int kFirstReservedNumber = 19000;
+  // Last field number reserved for the protocol buffer library implementation.
+  // Users may not declare fields that use reserved numbers.
+  static const int kLastReservedNumber = 19999;
+
+  const std::string& name() const;  // Name of this field within the message.
+  const std::string& full_name() const;  // Fully-qualified name of the field.
+  const std::string& json_name() const;  // JSON name of this field.
+  const FileDescriptor* file() const;  // File in which this field was defined.
+  bool is_extension() const;           // Is this an extension field?
+  int number() const;                  // Declared tag number.
+
+  // Same as name() except converted to lower-case.  This (and especially the
+  // FindFieldByLowercaseName() method) can be useful when parsing formats
+  // which prefer to use lowercase naming style.  (Although, technically
+  // field names should be lowercased anyway according to the protobuf style
+  // guide, so this only makes a difference when dealing with old .proto files
+  // which do not follow the guide.)
+  const std::string& lowercase_name() const;
+
+  // Same as name() except converted to camel-case.  In this conversion, any
+  // time an underscore appears in the name, it is removed and the next
+  // letter is capitalized.  Furthermore, the first letter of the name is
+  // lower-cased.  Examples:
+  //   FooBar -> fooBar
+  //   foo_bar -> fooBar
+  //   fooBar -> fooBar
+  // This (and especially the FindFieldByCamelcaseName() method) can be useful
+  // when parsing formats which prefer to use camel-case naming style.
+  const std::string& camelcase_name() const;
+
+  Type type() const;                  // Declared type of this field.
+  const char* type_name() const;      // Name of the declared type.
+  CppType cpp_type() const;           // C++ type of this field.
+  const char* cpp_type_name() const;  // Name of the C++ type.
+  Label label() const;                // optional/required/repeated
+
+  bool is_required() const;  // shorthand for label() == LABEL_REQUIRED
+  bool is_optional() const;  // shorthand for label() == LABEL_OPTIONAL
+  bool is_repeated() const;  // shorthand for label() == LABEL_REPEATED
+  bool is_packable() const;  // shorthand for is_repeated() &&
+                             //               IsTypePackable(type())
+  bool is_packed() const;    // shorthand for is_packable() &&
+                             //               options().packed()
+  bool is_map() const;       // shorthand for type() == TYPE_MESSAGE &&
+                             // message_type()->options().map_entry()
+
+  // Returns true if this field was syntactically written with "optional" in the
+  // .proto file. Excludes singular proto3 fields that do not have a label.
+  bool has_optional_keyword() const;
+
+  // Returns true if this field tracks presence, ie. does the field
+  // distinguish between "unset" and "present with default value."
+  // This includes required, optional, and oneof fields. It excludes maps,
+  // repeated fields, and singular proto3 fields without "optional".
+  //
+  // For fields where has_presence() == true, the return value of
+  // Reflection::HasField() is semantically meaningful.
+  bool has_presence() const;
+
+  // Index of this field within the message's field array, or the file or
+  // extension scope's extensions array.
+  int index() const;
+
+  // Does this field have an explicitly-declared default value?
+  bool has_default_value() const;
+
+  // Whether the user has specified the json_name field option in the .proto
+  // file.
+  bool has_json_name() const;
+
+  // Get the field default value if cpp_type() == CPPTYPE_INT32.  If no
+  // explicit default was defined, the default is 0.
+  int32 default_value_int32() const;
+  // Get the field default value if cpp_type() == CPPTYPE_INT64.  If no
+  // explicit default was defined, the default is 0.
+  int64 default_value_int64() const;
+  // Get the field default value if cpp_type() == CPPTYPE_UINT32.  If no
+  // explicit default was defined, the default is 0.
+  uint32 default_value_uint32() const;
+  // Get the field default value if cpp_type() == CPPTYPE_UINT64.  If no
+  // explicit default was defined, the default is 0.
+  uint64 default_value_uint64() const;
+  // Get the field default value if cpp_type() == CPPTYPE_FLOAT.  If no
+  // explicit default was defined, the default is 0.0.
+  float default_value_float() const;
+  // Get the field default value if cpp_type() == CPPTYPE_DOUBLE.  If no
+  // explicit default was defined, the default is 0.0.
+  double default_value_double() const;
+  // Get the field default value if cpp_type() == CPPTYPE_BOOL.  If no
+  // explicit default was defined, the default is false.
+  bool default_value_bool() const;
+  // Get the field default value if cpp_type() == CPPTYPE_ENUM.  If no
+  // explicit default was defined, the default is the first value defined
+  // in the enum type (all enum types are required to have at least one value).
+  // This never returns nullptr.
+  const EnumValueDescriptor* default_value_enum() const;
+  // Get the field default value if cpp_type() == CPPTYPE_STRING.  If no
+  // explicit default was defined, the default is the empty string.
+  const std::string& default_value_string() const;
+
+  // The Descriptor for the message of which this is a field.  For extensions,
+  // this is the extended type.  Never nullptr.
+  const Descriptor* containing_type() const;
+
+  // If the field is a member of a oneof, this is the one, otherwise this is
+  // nullptr.
+  const OneofDescriptor* containing_oneof() const;
+
+  // If the field is a member of a non-synthetic oneof, returns the descriptor
+  // for the oneof, otherwise returns nullptr.
+  const OneofDescriptor* real_containing_oneof() const;
+
+  // If the field is a member of a oneof, returns the index in that oneof.
+  int index_in_oneof() const;
+
+  // An extension may be declared within the scope of another message.  If this
+  // field is an extension (is_extension() is true), then extension_scope()
+  // returns that message, or nullptr if the extension was declared at global
+  // scope.  If this is not an extension, extension_scope() is undefined (may
+  // assert-fail).
+  const Descriptor* extension_scope() const;
+
+  // If type is TYPE_MESSAGE or TYPE_GROUP, returns a descriptor for the
+  // message or the group type.  Otherwise, returns null.
+  const Descriptor* message_type() const;
+  // If type is TYPE_ENUM, returns a descriptor for the enum.  Otherwise,
+  // returns null.
+  const EnumDescriptor* enum_type() const;
+
+  // Get the FieldOptions for this field.  This includes things listed in
+  // square brackets after the field definition.  E.g., the field:
+  //   optional string text = 1 [ctype=CORD];
+  // has the "ctype" option set.  Allowed options are defined by FieldOptions in
+  // descriptor.proto, and any available extensions of that message.
+  const FieldOptions& options() const;
+
+  // See Descriptor::CopyTo().
+  void CopyTo(FieldDescriptorProto* proto) const;
+
+  // See Descriptor::DebugString().
+  std::string DebugString() const;
+
+  // See Descriptor::DebugStringWithOptions().
+  std::string DebugStringWithOptions(const DebugStringOptions& options) const;
+
+  // Helper method to get the CppType for a particular Type.
+  static CppType TypeToCppType(Type type);
+
+  // Helper method to get the name of a Type.
+  static const char* TypeName(Type type);
+
+  // Helper method to get the name of a CppType.
+  static const char* CppTypeName(CppType cpp_type);
+
+  // Return true iff [packed = true] is valid for fields of this type.
+  static inline bool IsTypePackable(Type field_type);
+
+  // Returns full_name() except if the field is a MessageSet extension,
+  // in which case it returns the full_name() of the containing message type
+  // for backwards compatibility with proto1.
+  //
+  // A MessageSet extension is defined as an optional message extension
+  // whose containing type has the message_set_wire_format option set.
+  // This should be true of extensions of google.protobuf.bridge.MessageSet;
+  // by convention, such extensions are named "message_set_extension".
+  //
+  // The opposite operation (looking up an extension's FieldDescriptor given
+  // its printable name) can be accomplished with
+  //     message->file()->pool()->FindExtensionByPrintableName(message, name)
+  // where the extension extends "message".
+  const std::string& PrintableNameForExtension() const;
+
+  // Source Location ---------------------------------------------------
+
+  // Updates |*out_location| to the source location of the complete
+  // extent of this field declaration.  Returns false and leaves
+  // |*out_location| unchanged iff location information was not available.
+  bool GetSourceLocation(SourceLocation* out_location) const;
+
+ private:
+  typedef FieldOptions OptionsType;
+
+  // Allows access to GetLocationPath for annotations.
+  friend class io::Printer;
+  friend class compiler::cpp::Formatter;
+
+  // Fill the json_name field of FieldDescriptorProto.
+  void CopyJsonNameTo(FieldDescriptorProto* proto) const;
+
+  // See Descriptor::DebugString().
+  void DebugString(int depth, std::string* contents,
+                   const DebugStringOptions& options) const;
+
+  // formats the default value appropriately and returns it as a string.
+  // Must have a default value to call this. If quote_string_type is true, then
+  // types of CPPTYPE_STRING whill be surrounded by quotes and CEscaped.
+  std::string DefaultValueAsString(bool quote_string_type) const;
+
+  // Helper function that returns the field type name for DebugString.
+  std::string FieldTypeNameDebugString() const;
+
+  // Walks up the descriptor tree to generate the source location path
+  // to this descriptor from the file root.
+  void GetLocationPath(std::vector<int>* output) const;
+
+  // Returns true if this is a map message type.
+  bool is_map_message_type() const;
+
+  const std::string* name_;
+  const std::string* full_name_;
+  const std::string* lowercase_name_;
+  const std::string* camelcase_name_;
+  // If has_json_name_ is true, it's the value specified by the user.
+  // Otherwise, it has the same value as camelcase_name_.
+  const std::string* json_name_;
+  const FileDescriptor* file_;
+  internal::once_flag* type_once_;
+  static void TypeOnceInit(const FieldDescriptor* to_init);
+  void InternalTypeOnceInit() const;
+  mutable Type type_;
+  Label label_;
+  bool has_default_value_;
+  bool proto3_optional_;
+  // Whether the user has specified the json_name field option in the .proto
+  // file.
+  bool has_json_name_;
+  bool is_extension_;
+  int number_;
+  int index_in_oneof_;
+  const Descriptor* containing_type_;
+  const OneofDescriptor* containing_oneof_;
+  const Descriptor* extension_scope_;
+  mutable const Descriptor* message_type_;
+  mutable const EnumDescriptor* enum_type_;
+  const FieldOptions* options_;
+  const std::string* type_name_;
+  const std::string* default_value_enum_name_;
+  // IMPORTANT:  If you add a new field, make sure to search for all instances
+  // of Allocate<FieldDescriptor>() and AllocateArray<FieldDescriptor>() in
+  // descriptor.cc and update them to initialize the field.
+
+  union {
+    int32 default_value_int32_;
+    int64 default_value_int64_;
+    uint32 default_value_uint32_;
+    uint64 default_value_uint64_;
+    float default_value_float_;
+    double default_value_double_;
+    bool default_value_bool_;
+
+    mutable const EnumValueDescriptor* default_value_enum_;
+    const std::string* default_value_string_;
+  };
+
+  static const CppType kTypeToCppTypeMap[MAX_TYPE + 1];
+
+  static const char* const kTypeToName[MAX_TYPE + 1];
+
+  static const char* const kCppTypeToName[MAX_CPPTYPE + 1];
+
+  static const char* const kLabelToName[MAX_LABEL + 1];
+
+  // Must be constructed using DescriptorPool.
+  FieldDescriptor() {}
+  friend class DescriptorBuilder;
+  friend class FileDescriptor;
+  friend class Descriptor;
+  friend class OneofDescriptor;
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FieldDescriptor);
+};
+
+
+// Describes a oneof defined in a message type.
+class PROTOBUF_EXPORT OneofDescriptor {
+ public:
+  typedef OneofDescriptorProto Proto;
+
+  const std::string& name() const;       // Name of this oneof.
+  const std::string& full_name() const;  // Fully-qualified name of the oneof.
+
+  // Index of this oneof within the message's oneof array.
+  int index() const;
+
+  // Returns whether this oneof was inserted by the compiler to wrap a proto3
+  // optional field. If this returns true, code generators should *not* emit it.
+  bool is_synthetic() const;
+
+  // The .proto file in which this oneof was defined.  Never nullptr.
+  const FileDescriptor* file() const;
+  // The Descriptor for the message containing this oneof.
+  const Descriptor* containing_type() const;
+
+  // The number of (non-extension) fields which are members of this oneof.
+  int field_count() const;
+  // Get a member of this oneof, in the order in which they were declared in the
+  // .proto file.  Does not include extensions.
+  const FieldDescriptor* field(int index) const;
+
+  const OneofOptions& options() const;
+
+  // See Descriptor::CopyTo().
+  void CopyTo(OneofDescriptorProto* proto) const;
+
+  // See Descriptor::DebugString().
+  std::string DebugString() const;
+
+  // See Descriptor::DebugStringWithOptions().
+  std::string DebugStringWithOptions(const DebugStringOptions& options) const;
+
+  // Source Location ---------------------------------------------------
+
+  // Updates |*out_location| to the source location of the complete
+  // extent of this oneof declaration.  Returns false and leaves
+  // |*out_location| unchanged iff location information was not available.
+  bool GetSourceLocation(SourceLocation* out_location) const;
+
+ private:
+  typedef OneofOptions OptionsType;
+
+  // Allows access to GetLocationPath for annotations.
+  friend class io::Printer;
+  friend class compiler::cpp::Formatter;
+
+  // See Descriptor::DebugString().
+  void DebugString(int depth, std::string* contents,
+                   const DebugStringOptions& options) const;
+
+  // Walks up the descriptor tree to generate the source location path
+  // to this descriptor from the file root.
+  void GetLocationPath(std::vector<int>* output) const;
+
+  const std::string* name_;
+  const std::string* full_name_;
+  const Descriptor* containing_type_;
+  int field_count_;
+  const FieldDescriptor** fields_;
+  const OneofOptions* options_;
+
+  // IMPORTANT:  If you add a new field, make sure to search for all instances
+  // of Allocate<OneofDescriptor>() and AllocateArray<OneofDescriptor>()
+  // in descriptor.cc and update them to initialize the field.
+
+  // Must be constructed using DescriptorPool.
+  OneofDescriptor() {}
+  friend class DescriptorBuilder;
+  friend class Descriptor;
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(OneofDescriptor);
+};
+
+// Describes an enum type defined in a .proto file.  To get the EnumDescriptor
+// for a generated enum type, call TypeName_descriptor().  Use DescriptorPool
+// to construct your own descriptors.
+class PROTOBUF_EXPORT EnumDescriptor {
+ public:
+  typedef EnumDescriptorProto Proto;
+
+  // The name of this enum type in the containing scope.
+  const std::string& name() const;
+
+  // The fully-qualified name of the enum type, scope delimited by periods.
+  const std::string& full_name() const;
+
+  // Index of this enum within the file or containing message's enum array.
+  int index() const;
+
+  // The .proto file in which this enum type was defined.  Never nullptr.
+  const FileDescriptor* file() const;
+
+  // The number of values for this EnumDescriptor.  Guaranteed to be greater
+  // than zero.
+  int value_count() const;
+  // Gets a value by index, where 0 <= index < value_count().
+  // These are returned in the order they were defined in the .proto file.
+  const EnumValueDescriptor* value(int index) const;
+
+  // Looks up a value by name.  Returns nullptr if no such value exists.
+  const EnumValueDescriptor* FindValueByName(const std::string& name) const;
+  // Looks up a value by number.  Returns nullptr if no such value exists.  If
+  // multiple values have this number, the first one defined is returned.
+  const EnumValueDescriptor* FindValueByNumber(int number) const;
+
+  // If this enum type is nested in a message type, this is that message type.
+  // Otherwise, nullptr.
+  const Descriptor* containing_type() const;
+
+  // Get options for this enum type.  These are specified in the .proto file by
+  // placing lines like "option foo = 1234;" in the enum definition.  Allowed
+  // options are defined by EnumOptions in descriptor.proto, and any available
+  // extensions of that message.
+  const EnumOptions& options() const;
+
+  // See Descriptor::CopyTo().
+  void CopyTo(EnumDescriptorProto* proto) const;
+
+  // See Descriptor::DebugString().
+  std::string DebugString() const;
+
+  // See Descriptor::DebugStringWithOptions().
+  std::string DebugStringWithOptions(const DebugStringOptions& options) const;
+
+  // Returns true if this is a placeholder for an unknown enum. This will
+  // only be the case if this descriptor comes from a DescriptorPool
+  // with AllowUnknownDependencies() set.
+  bool is_placeholder() const;
+
+  // Reserved fields -------------------------------------------------
+
+  // A range of reserved field numbers.
+  struct ReservedRange {
+    int start;  // inclusive
+    int end;    // inclusive
+  };
+
+  // The number of reserved ranges in this message type.
+  int reserved_range_count() const;
+  // Gets an reserved range by index, where 0 <= index <
+  // reserved_range_count(). These are returned in the order they were defined
+  // in the .proto file.
+  const EnumDescriptor::ReservedRange* reserved_range(int index) const;
+
+  // Returns true if the number is in one of the reserved ranges.
+  bool IsReservedNumber(int number) const;
+
+  // Returns nullptr if no reserved range contains the given number.
+  const EnumDescriptor::ReservedRange* FindReservedRangeContainingNumber(
+      int number) const;
+
+  // The number of reserved field names in this message type.
+  int reserved_name_count() const;
+
+  // Gets a reserved name by index, where 0 <= index < reserved_name_count().
+  const std::string& reserved_name(int index) const;
+
+  // Returns true if the field name is reserved.
+  bool IsReservedName(const std::string& name) const;
+
+  // Source Location ---------------------------------------------------
+
+  // Updates |*out_location| to the source location of the complete
+  // extent of this enum declaration.  Returns false and leaves
+  // |*out_location| unchanged iff location information was not available.
+  bool GetSourceLocation(SourceLocation* out_location) const;
+
+ private:
+  typedef EnumOptions OptionsType;
+
+  // Allows access to GetLocationPath for annotations.
+  friend class io::Printer;
+  friend class compiler::cpp::Formatter;
+
+  // Looks up a value by number.  If the value does not exist, dynamically
+  // creates a new EnumValueDescriptor for that value, assuming that it was
+  // unknown. If a new descriptor is created, this is done in a thread-safe way,
+  // and future calls will return the same value descriptor pointer.
+  //
+  // This is private but is used by Reflection (which is friended below) to
+  // return a valid EnumValueDescriptor from GetEnum() when this feature is
+  // enabled.
+  const EnumValueDescriptor* FindValueByNumberCreatingIfUnknown(
+      int number) const;
+
+  // See Descriptor::DebugString().
+  void DebugString(int depth, std::string* contents,
+                   const DebugStringOptions& options) const;
+
+  // Walks up the descriptor tree to generate the source location path
+  // to this descriptor from the file root.
+  void GetLocationPath(std::vector<int>* output) const;
+
+  const std::string* name_;
+  const std::string* full_name_;
+  const FileDescriptor* file_;
+  const Descriptor* containing_type_;
+  const EnumOptions* options_;
+
+  // True if this is a placeholder for an unknown type.
+  bool is_placeholder_;
+  // True if this is a placeholder and the type name wasn't fully-qualified.
+  bool is_unqualified_placeholder_;
+
+  int value_count_;
+  EnumValueDescriptor* values_;
+
+  int reserved_range_count_;
+  int reserved_name_count_;
+  EnumDescriptor::ReservedRange* reserved_ranges_;
+  const std::string** reserved_names_;
+
+  // IMPORTANT:  If you add a new field, make sure to search for all instances
+  // of Allocate<EnumDescriptor>() and AllocateArray<EnumDescriptor>() in
+  // descriptor.cc and update them to initialize the field.
+
+  // Must be constructed using DescriptorPool.
+  EnumDescriptor() {}
+  friend class DescriptorBuilder;
+  friend class Descriptor;
+  friend class FieldDescriptor;
+  friend class EnumValueDescriptor;
+  friend class FileDescriptor;
+  friend class DescriptorPool;
+  friend class Reflection;
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(EnumDescriptor);
+};
+
+// Describes an individual enum constant of a particular type.  To get the
+// EnumValueDescriptor for a given enum value, first get the EnumDescriptor
+// for its type, then use EnumDescriptor::FindValueByName() or
+// EnumDescriptor::FindValueByNumber().  Use DescriptorPool to construct
+// your own descriptors.
+class PROTOBUF_EXPORT EnumValueDescriptor {
+ public:
+  typedef EnumValueDescriptorProto Proto;
+
+  const std::string& name() const;  // Name of this enum constant.
+  int index() const;                // Index within the enums's Descriptor.
+  int number() const;               // Numeric value of this enum constant.
+
+  // The full_name of an enum value is a sibling symbol of the enum type.
+  // e.g. the full name of FieldDescriptorProto::TYPE_INT32 is actually
+  // "google.protobuf.FieldDescriptorProto.TYPE_INT32", NOT
+  // "google.protobuf.FieldDescriptorProto.Type.TYPE_INT32".  This is to conform
+  // with C++ scoping rules for enums.
+  const std::string& full_name() const;
+
+  // The .proto file in which this value was defined.  Never nullptr.
+  const FileDescriptor* file() const;
+  // The type of this value.  Never nullptr.
+  const EnumDescriptor* type() const;
+
+  // Get options for this enum value.  These are specified in the .proto file by
+  // adding text like "[foo = 1234]" after an enum value definition.  Allowed
+  // options are defined by EnumValueOptions in descriptor.proto, and any
+  // available extensions of that message.
+  const EnumValueOptions& options() const;
+
+  // See Descriptor::CopyTo().
+  void CopyTo(EnumValueDescriptorProto* proto) const;
+
+  // See Descriptor::DebugString().
+  std::string DebugString() const;
+
+  // See Descriptor::DebugStringWithOptions().
+  std::string DebugStringWithOptions(const DebugStringOptions& options) const;
+
+  // Source Location ---------------------------------------------------
+
+  // Updates |*out_location| to the source location of the complete
+  // extent of this enum value declaration.  Returns false and leaves
+  // |*out_location| unchanged iff location information was not available.
+  bool GetSourceLocation(SourceLocation* out_location) const;
+
+ private:
+  typedef EnumValueOptions OptionsType;
+
+  // Allows access to GetLocationPath for annotations.
+  friend class io::Printer;
+  friend class compiler::cpp::Formatter;
+
+  // See Descriptor::DebugString().
+  void DebugString(int depth, std::string* contents,
+                   const DebugStringOptions& options) const;
+
+  // Walks up the descriptor tree to generate the source location path
+  // to this descriptor from the file root.
+  void GetLocationPath(std::vector<int>* output) const;
+
+  const std::string* name_;
+  const std::string* full_name_;
+  int number_;
+  const EnumDescriptor* type_;
+  const EnumValueOptions* options_;
+  // IMPORTANT:  If you add a new field, make sure to search for all instances
+  // of Allocate<EnumValueDescriptor>() and AllocateArray<EnumValueDescriptor>()
+  // in descriptor.cc and update them to initialize the field.
+
+  // Must be constructed using DescriptorPool.
+  EnumValueDescriptor() {}
+  friend class DescriptorBuilder;
+  friend class EnumDescriptor;
+  friend class DescriptorPool;
+  friend class FileDescriptorTables;
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(EnumValueDescriptor);
+};
+
+// Describes an RPC service. Use DescriptorPool to construct your own
+// descriptors.
+class PROTOBUF_EXPORT ServiceDescriptor {
+ public:
+  typedef ServiceDescriptorProto Proto;
+
+  // The name of the service, not including its containing scope.
+  const std::string& name() const;
+  // The fully-qualified name of the service, scope delimited by periods.
+  const std::string& full_name() const;
+  // Index of this service within the file's services array.
+  int index() const;
+
+  // The .proto file in which this service was defined.  Never nullptr.
+  const FileDescriptor* file() const;
+
+  // Get options for this service type.  These are specified in the .proto file
+  // by placing lines like "option foo = 1234;" in the service definition.
+  // Allowed options are defined by ServiceOptions in descriptor.proto, and any
+  // available extensions of that message.
+  const ServiceOptions& options() const;
+
+  // The number of methods this service defines.
+  int method_count() const;
+  // Gets a MethodDescriptor by index, where 0 <= index < method_count().
+  // These are returned in the order they were defined in the .proto file.
+  const MethodDescriptor* method(int index) const;
+
+  // Look up a MethodDescriptor by name.
+  const MethodDescriptor* FindMethodByName(const std::string& name) const;
+  // See Descriptor::CopyTo().
+  void CopyTo(ServiceDescriptorProto* proto) const;
+
+  // See Descriptor::DebugString().
+  std::string DebugString() const;
+
+  // See Descriptor::DebugStringWithOptions().
+  std::string DebugStringWithOptions(const DebugStringOptions& options) const;
+
+  // Source Location ---------------------------------------------------
+
+  // Updates |*out_location| to the source location of the complete
+  // extent of this service declaration.  Returns false and leaves
+  // |*out_location| unchanged iff location information was not available.
+  bool GetSourceLocation(SourceLocation* out_location) const;
+
+ private:
+  typedef ServiceOptions OptionsType;
+
+  // Allows access to GetLocationPath for annotations.
+  friend class io::Printer;
+  friend class compiler::cpp::Formatter;
+
+  // See Descriptor::DebugString().
+  void DebugString(std::string* contents,
+                   const DebugStringOptions& options) const;
+
+  // Walks up the descriptor tree to generate the source location path
+  // to this descriptor from the file root.
+  void GetLocationPath(std::vector<int>* output) const;
+
+  const std::string* name_;
+  const std::string* full_name_;
+  const FileDescriptor* file_;
+  const ServiceOptions* options_;
+  MethodDescriptor* methods_;
+  int method_count_;
+  // IMPORTANT:  If you add a new field, make sure to search for all instances
+  // of Allocate<ServiceDescriptor>() and AllocateArray<ServiceDescriptor>() in
+  // descriptor.cc and update them to initialize the field.
+
+  // Must be constructed using DescriptorPool.
+  ServiceDescriptor() {}
+  friend class DescriptorBuilder;
+  friend class FileDescriptor;
+  friend class MethodDescriptor;
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ServiceDescriptor);
+};
+
+
+// Describes an individual service method.  To obtain a MethodDescriptor given
+// a service, first get its ServiceDescriptor, then call
+// ServiceDescriptor::FindMethodByName().  Use DescriptorPool to construct your
+// own descriptors.
+class PROTOBUF_EXPORT MethodDescriptor {
+ public:
+  typedef MethodDescriptorProto Proto;
+
+  // Name of this method, not including containing scope.
+  const std::string& name() const;
+  // The fully-qualified name of the method, scope delimited by periods.
+  const std::string& full_name() const;
+  // Index within the service's Descriptor.
+  int index() const;
+
+  // The .proto file in which this method was defined.  Never nullptr.
+  const FileDescriptor* file() const;
+  // Gets the service to which this method belongs.  Never nullptr.
+  const ServiceDescriptor* service() const;
+
+  // Gets the type of protocol message which this method accepts as input.
+  const Descriptor* input_type() const;
+  // Gets the type of protocol message which this message produces as output.
+  const Descriptor* output_type() const;
+
+  // Gets whether the client streams multiple requests.
+  bool client_streaming() const;
+  // Gets whether the server streams multiple responses.
+  bool server_streaming() const;
+
+  // Get options for this method.  These are specified in the .proto file by
+  // placing lines like "option foo = 1234;" in curly-braces after a method
+  // declaration.  Allowed options are defined by MethodOptions in
+  // descriptor.proto, and any available extensions of that message.
+  const MethodOptions& options() const;
+
+  // See Descriptor::CopyTo().
+  void CopyTo(MethodDescriptorProto* proto) const;
+
+  // See Descriptor::DebugString().
+  std::string DebugString() const;
+
+  // See Descriptor::DebugStringWithOptions().
+  std::string DebugStringWithOptions(const DebugStringOptions& options) const;
+
+  // Source Location ---------------------------------------------------
+
+  // Updates |*out_location| to the source location of the complete
+  // extent of this method declaration.  Returns false and leaves
+  // |*out_location| unchanged iff location information was not available.
+  bool GetSourceLocation(SourceLocation* out_location) const;
+
+ private:
+  typedef MethodOptions OptionsType;
+
+  // Allows access to GetLocationPath for annotations.
+  friend class io::Printer;
+  friend class compiler::cpp::Formatter;
+
+  // See Descriptor::DebugString().
+  void DebugString(int depth, std::string* contents,
+                   const DebugStringOptions& options) const;
+
+  // Walks up the descriptor tree to generate the source location path
+  // to this descriptor from the file root.
+  void GetLocationPath(std::vector<int>* output) const;
+
+  const std::string* name_;
+  const std::string* full_name_;
+  const ServiceDescriptor* service_;
+  mutable internal::LazyDescriptor input_type_;
+  mutable internal::LazyDescriptor output_type_;
+  const MethodOptions* options_;
+  bool client_streaming_;
+  bool server_streaming_;
+  // IMPORTANT:  If you add a new field, make sure to search for all instances
+  // of Allocate<MethodDescriptor>() and AllocateArray<MethodDescriptor>() in
+  // descriptor.cc and update them to initialize the field.
+
+  // Must be constructed using DescriptorPool.
+  MethodDescriptor() {}
+  friend class DescriptorBuilder;
+  friend class ServiceDescriptor;
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MethodDescriptor);
+};
+
+
+// Describes a whole .proto file.  To get the FileDescriptor for a compiled-in
+// file, get the descriptor for something defined in that file and call
+// descriptor->file().  Use DescriptorPool to construct your own descriptors.
+class PROTOBUF_EXPORT FileDescriptor {
+ public:
+  typedef FileDescriptorProto Proto;
+
+  // The filename, relative to the source tree.
+  // e.g. "foo/bar/baz.proto"
+  const std::string& name() const;
+
+  // The package, e.g. "google.protobuf.compiler".
+  const std::string& package() const;
+
+  // The DescriptorPool in which this FileDescriptor and all its contents were
+  // allocated.  Never nullptr.
+  const DescriptorPool* pool() const;
+
+  // The number of files imported by this one.
+  int dependency_count() const;
+  // Gets an imported file by index, where 0 <= index < dependency_count().
+  // These are returned in the order they were defined in the .proto file.
+  const FileDescriptor* dependency(int index) const;
+
+  // The number of files public imported by this one.
+  // The public dependency list is a subset of the dependency list.
+  int public_dependency_count() const;
+  // Gets a public imported file by index, where 0 <= index <
+  // public_dependency_count().
+  // These are returned in the order they were defined in the .proto file.
+  const FileDescriptor* public_dependency(int index) const;
+
+  // The number of files that are imported for weak fields.
+  // The weak dependency list is a subset of the dependency list.
+  int weak_dependency_count() const;
+  // Gets a weak imported file by index, where 0 <= index <
+  // weak_dependency_count().
+  // These are returned in the order they were defined in the .proto file.
+  const FileDescriptor* weak_dependency(int index) const;
+
+  // Number of top-level message types defined in this file.  (This does not
+  // include nested types.)
+  int message_type_count() const;
+  // Gets a top-level message type, where 0 <= index < message_type_count().
+  // These are returned in the order they were defined in the .proto file.
+  const Descriptor* message_type(int index) const;
+
+  // Number of top-level enum types defined in this file.  (This does not
+  // include nested types.)
+  int enum_type_count() const;
+  // Gets a top-level enum type, where 0 <= index < enum_type_count().
+  // These are returned in the order they were defined in the .proto file.
+  const EnumDescriptor* enum_type(int index) const;
+
+  // Number of services defined in this file.
+  int service_count() const;
+  // Gets a service, where 0 <= index < service_count().
+  // These are returned in the order they were defined in the .proto file.
+  const ServiceDescriptor* service(int index) const;
+
+  // Number of extensions defined at file scope.  (This does not include
+  // extensions nested within message types.)
+  int extension_count() const;
+  // Gets an extension's descriptor, where 0 <= index < extension_count().
+  // These are returned in the order they were defined in the .proto file.
+  const FieldDescriptor* extension(int index) const;
+
+  // Get options for this file.  These are specified in the .proto file by
+  // placing lines like "option foo = 1234;" at the top level, outside of any
+  // other definitions.  Allowed options are defined by FileOptions in
+  // descriptor.proto, and any available extensions of that message.
+  const FileOptions& options() const;
+
+  // Syntax of this file.
+  enum Syntax {
+    SYNTAX_UNKNOWN = 0,
+    SYNTAX_PROTO2 = 2,
+    SYNTAX_PROTO3 = 3,
+  };
+  Syntax syntax() const;
+  static const char* SyntaxName(Syntax syntax);
+
+  // Find a top-level message type by name.  Returns nullptr if not found.
+  const Descriptor* FindMessageTypeByName(const std::string& name) const;
+  // Find a top-level enum type by name.  Returns nullptr if not found.
+  const EnumDescriptor* FindEnumTypeByName(const std::string& name) const;
+  // Find an enum value defined in any top-level enum by name.  Returns nullptr
+  // if not found.
+  const EnumValueDescriptor* FindEnumValueByName(const std::string& name) const;
+  // Find a service definition by name.  Returns nullptr if not found.
+  const ServiceDescriptor* FindServiceByName(const std::string& name) const;
+  // Find a top-level extension definition by name.  Returns nullptr if not
+  // found.
+  const FieldDescriptor* FindExtensionByName(const std::string& name) const;
+  // Similar to FindExtensionByName(), but searches by lowercased-name.  See
+  // Descriptor::FindFieldByLowercaseName().
+  const FieldDescriptor* FindExtensionByLowercaseName(
+      const std::string& name) const;
+  // Similar to FindExtensionByName(), but searches by camelcased-name.  See
+  // Descriptor::FindFieldByCamelcaseName().
+  const FieldDescriptor* FindExtensionByCamelcaseName(
+      const std::string& name) const;
+
+  // See Descriptor::CopyTo().
+  // Notes:
+  // - This method does NOT copy source code information since it is relatively
+  //   large and rarely needed.  See CopySourceCodeInfoTo() below.
+  void CopyTo(FileDescriptorProto* proto) const;
+  // Write the source code information of this FileDescriptor into the given
+  // FileDescriptorProto.  See CopyTo() above.
+  void CopySourceCodeInfoTo(FileDescriptorProto* proto) const;
+  // Fill the json_name field of FieldDescriptorProto for all fields. Can only
+  // be called after CopyTo().
+  void CopyJsonNameTo(FileDescriptorProto* proto) const;
+
+  // See Descriptor::DebugString().
+  std::string DebugString() const;
+
+  // See Descriptor::DebugStringWithOptions().
+  std::string DebugStringWithOptions(const DebugStringOptions& options) const;
+
+  // Returns true if this is a placeholder for an unknown file. This will
+  // only be the case if this descriptor comes from a DescriptorPool
+  // with AllowUnknownDependencies() set.
+  bool is_placeholder() const;
+
+  // Updates |*out_location| to the source location of the complete extent of
+  // this file declaration (namely, the empty path).
+  bool GetSourceLocation(SourceLocation* out_location) const;
+
+  // Updates |*out_location| to the source location of the complete
+  // extent of the declaration or declaration-part denoted by |path|.
+  // Returns false and leaves |*out_location| unchanged iff location
+  // information was not available.  (See SourceCodeInfo for
+  // description of path encoding.)
+  bool GetSourceLocation(const std::vector<int>& path,
+                         SourceLocation* out_location) const;
+
+ private:
+  typedef FileOptions OptionsType;
+
+  const std::string* name_;
+  const std::string* package_;
+  const DescriptorPool* pool_;
+  internal::once_flag* dependencies_once_;
+  static void DependenciesOnceInit(const FileDescriptor* to_init);
+  void InternalDependenciesOnceInit() const;
+
+  // These are arranged to minimize padding on 64-bit.
+  int dependency_count_;
+  int public_dependency_count_;
+  int weak_dependency_count_;
+  int message_type_count_;
+  int enum_type_count_;
+  int service_count_;
+  int extension_count_;
+  Syntax syntax_;
+  bool is_placeholder_;
+
+  // Indicates the FileDescriptor is completed building. Used to verify
+  // that type accessor functions that can possibly build a dependent file
+  // aren't called during the process of building the file.
+  bool finished_building_;
+
+  mutable const FileDescriptor** dependencies_;
+  const std::string** dependencies_names_;
+  int* public_dependencies_;
+  int* weak_dependencies_;
+  Descriptor* message_types_;
+  EnumDescriptor* enum_types_;
+  ServiceDescriptor* services_;
+  FieldDescriptor* extensions_;
+  const FileOptions* options_;
+
+  const FileDescriptorTables* tables_;
+  const SourceCodeInfo* source_code_info_;
+
+  // IMPORTANT:  If you add a new field, make sure to search for all instances
+  // of Allocate<FileDescriptor>() and AllocateArray<FileDescriptor>() in
+  // descriptor.cc and update them to initialize the field.
+
+  FileDescriptor() {}
+  friend class DescriptorBuilder;
+  friend class DescriptorPool;
+  friend class Descriptor;
+  friend class FieldDescriptor;
+  friend class internal::LazyDescriptor;
+  friend class OneofDescriptor;
+  friend class EnumDescriptor;
+  friend class EnumValueDescriptor;
+  friend class MethodDescriptor;
+  friend class ServiceDescriptor;
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FileDescriptor);
+};
+
+
+// ===================================================================
+
+// Used to construct descriptors.
+//
+// Normally you won't want to build your own descriptors.  Message classes
+// constructed by the protocol compiler will provide them for you.  However,
+// if you are implementing Message on your own, or if you are writing a
+// program which can operate on totally arbitrary types and needs to load
+// them from some sort of database, you might need to.
+//
+// Since Descriptors are composed of a whole lot of cross-linked bits of
+// data that would be a pain to put together manually, the
+// DescriptorPool class is provided to make the process easier.  It can
+// take a FileDescriptorProto (defined in descriptor.proto), validate it,
+// and convert it to a set of nicely cross-linked Descriptors.
+//
+// DescriptorPool also helps with memory management.  Descriptors are
+// composed of many objects containing static data and pointers to each
+// other.  In all likelihood, when it comes time to delete this data,
+// you'll want to delete it all at once.  In fact, it is not uncommon to
+// have a whole pool of descriptors all cross-linked with each other which
+// you wish to delete all at once.  This class represents such a pool, and
+// handles the memory management for you.
+//
+// You can also search for descriptors within a DescriptorPool by name, and
+// extensions by number.
+class PROTOBUF_EXPORT DescriptorPool {
+ public:
+  // Create a normal, empty DescriptorPool.
+  DescriptorPool();
+
+  // Constructs a DescriptorPool that, when it can't find something among the
+  // descriptors already in the pool, looks for it in the given
+  // DescriptorDatabase.
+  // Notes:
+  // - If a DescriptorPool is constructed this way, its BuildFile*() methods
+  //   must not be called (they will assert-fail).  The only way to populate
+  //   the pool with descriptors is to call the Find*By*() methods.
+  // - The Find*By*() methods may block the calling thread if the
+  //   DescriptorDatabase blocks.  This in turn means that parsing messages
+  //   may block if they need to look up extensions.
+  // - The Find*By*() methods will use mutexes for thread-safety, thus making
+  //   them slower even when they don't have to fall back to the database.
+  //   In fact, even the Find*By*() methods of descriptor objects owned by
+  //   this pool will be slower, since they will have to obtain locks too.
+  // - An ErrorCollector may optionally be given to collect validation errors
+  //   in files loaded from the database.  If not given, errors will be printed
+  //   to GOOGLE_LOG(ERROR).  Remember that files are built on-demand, so this
+  //   ErrorCollector may be called from any thread that calls one of the
+  //   Find*By*() methods.
+  // - The DescriptorDatabase must not be mutated during the lifetime of
+  //   the DescriptorPool. Even if the client takes care to avoid data races,
+  //   changes to the content of the DescriptorDatabase may not be reflected
+  //   in subsequent lookups in the DescriptorPool.
+  class ErrorCollector;
+  explicit DescriptorPool(DescriptorDatabase* fallback_database,
+                          ErrorCollector* error_collector = nullptr);
+
+  ~DescriptorPool();
+
+  // Get a pointer to the generated pool.  Generated protocol message classes
+  // which are compiled into the binary will allocate their descriptors in
+  // this pool.  Do not add your own descriptors to this pool.
+  static const DescriptorPool* generated_pool();
+
+
+  // Find a FileDescriptor in the pool by file name.  Returns nullptr if not
+  // found.
+  const FileDescriptor* FindFileByName(const std::string& name) const;
+
+  // Find the FileDescriptor in the pool which defines the given symbol.
+  // If any of the Find*ByName() methods below would succeed, then this is
+  // equivalent to calling that method and calling the result's file() method.
+  // Otherwise this returns nullptr.
+  const FileDescriptor* FindFileContainingSymbol(
+      const std::string& symbol_name) const;
+
+  // Looking up descriptors ------------------------------------------
+  // These find descriptors by fully-qualified name.  These will find both
+  // top-level descriptors and nested descriptors.  They return nullptr if not
+  // found.
+
+  const Descriptor* FindMessageTypeByName(const std::string& name) const;
+  const FieldDescriptor* FindFieldByName(const std::string& name) const;
+  const FieldDescriptor* FindExtensionByName(const std::string& name) const;
+  const OneofDescriptor* FindOneofByName(const std::string& name) const;
+  const EnumDescriptor* FindEnumTypeByName(const std::string& name) const;
+  const EnumValueDescriptor* FindEnumValueByName(const std::string& name) const;
+  const ServiceDescriptor* FindServiceByName(const std::string& name) const;
+  const MethodDescriptor* FindMethodByName(const std::string& name) const;
+
+  // Finds an extension of the given type by number.  The extendee must be
+  // a member of this DescriptorPool or one of its underlays.
+  const FieldDescriptor* FindExtensionByNumber(const Descriptor* extendee,
+                                               int number) const;
+
+  // Finds an extension of the given type by its printable name.
+  // See comments above PrintableNameForExtension() for the definition of
+  // "printable name".  The extendee must be a member of this DescriptorPool
+  // or one of its underlays.  Returns nullptr if there is no known message
+  // extension with the given printable name.
+  const FieldDescriptor* FindExtensionByPrintableName(
+      const Descriptor* extendee, const std::string& printable_name) const;
+
+  // Finds extensions of extendee. The extensions will be appended to
+  // out in an undefined order. Only extensions defined directly in
+  // this DescriptorPool or one of its underlays are guaranteed to be
+  // found: extensions defined in the fallback database might not be found
+  // depending on the database implementation.
+  void FindAllExtensions(const Descriptor* extendee,
+                         std::vector<const FieldDescriptor*>* out) const;
+
+  // Building descriptors --------------------------------------------
+
+  // When converting a FileDescriptorProto to a FileDescriptor, various
+  // errors might be detected in the input.  The caller may handle these
+  // programmatically by implementing an ErrorCollector.
+  class PROTOBUF_EXPORT ErrorCollector {
+   public:
+    inline ErrorCollector() {}
+    virtual ~ErrorCollector();
+
+    // These constants specify what exact part of the construct is broken.
+    // This is useful e.g. for mapping the error back to an exact location
+    // in a .proto file.
+    enum ErrorLocation {
+      NAME,           // the symbol name, or the package name for files
+      NUMBER,         // field or extension range number
+      TYPE,           // field type
+      EXTENDEE,       // field extendee
+      DEFAULT_VALUE,  // field default value
+      INPUT_TYPE,     // method input type
+      OUTPUT_TYPE,    // method output type
+      OPTION_NAME,    // name in assignment
+      OPTION_VALUE,   // value in option assignment
+      IMPORT,         // import error
+      OTHER           // some other problem
+    };
+
+    // Reports an error in the FileDescriptorProto. Use this function if the
+    // problem occurred should interrupt building the FileDescriptorProto.
+    virtual void AddError(
+        const std::string& filename,  // File name in which the error occurred.
+        const std::string& element_name,  // Full name of the erroneous element.
+        const Message* descriptor,  // Descriptor of the erroneous element.
+        ErrorLocation location,     // One of the location constants, above.
+        const std::string& message  // Human-readable error message.
+        ) = 0;
+
+    // Reports a warning in the FileDescriptorProto. Use this function if the
+    // problem occurred should NOT interrupt building the FileDescriptorProto.
+    virtual void AddWarning(
+        const std::string& /*filename*/,      // File name in which the error
+                                              // occurred.
+        const std::string& /*element_name*/,  // Full name of the erroneous
+                                              // element.
+        const Message* /*descriptor*/,  // Descriptor of the erroneous element.
+        ErrorLocation /*location*/,     // One of the location constants, above.
+        const std::string& /*message*/  // Human-readable error message.
+    ) {}
+
+   private:
+    GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ErrorCollector);
+  };
+
+  // Convert the FileDescriptorProto to real descriptors and place them in
+  // this DescriptorPool.  All dependencies of the file must already be in
+  // the pool.  Returns the resulting FileDescriptor, or nullptr if there were
+  // problems with the input (e.g. the message was invalid, or dependencies
+  // were missing).  Details about the errors are written to GOOGLE_LOG(ERROR).
+  const FileDescriptor* BuildFile(const FileDescriptorProto& proto);
+
+  // Same as BuildFile() except errors are sent to the given ErrorCollector.
+  const FileDescriptor* BuildFileCollectingErrors(
+      const FileDescriptorProto& proto, ErrorCollector* error_collector);
+
+  // By default, it is an error if a FileDescriptorProto contains references
+  // to types or other files that are not found in the DescriptorPool (or its
+  // backing DescriptorDatabase, if any).  If you call
+  // AllowUnknownDependencies(), however, then unknown types and files
+  // will be replaced by placeholder descriptors (which can be identified by
+  // the is_placeholder() method).  This can allow you to
+  // perform some useful operations with a .proto file even if you do not
+  // have access to other .proto files on which it depends.  However, some
+  // heuristics must be used to fill in the gaps in information, and these
+  // can lead to descriptors which are inaccurate.  For example, the
+  // DescriptorPool may be forced to guess whether an unknown type is a message
+  // or an enum, as well as what package it resides in.  Furthermore,
+  // placeholder types will not be discoverable via FindMessageTypeByName()
+  // and similar methods, which could confuse some descriptor-based algorithms.
+  // Generally, the results of this option should be handled with extreme care.
+  void AllowUnknownDependencies() { allow_unknown_ = true; }
+
+  // By default, weak imports are allowed to be missing, in which case we will
+  // use a placeholder for the dependency and convert the field to be an Empty
+  // message field. If you call EnforceWeakDependencies(true), however, the
+  // DescriptorPool will report a import not found error.
+  void EnforceWeakDependencies(bool enforce) { enforce_weak_ = enforce; }
+
+  // Internal stuff --------------------------------------------------
+  // These methods MUST NOT be called from outside the proto2 library.
+  // These methods may contain hidden pitfalls and may be removed in a
+  // future library version.
+
+  // Create a DescriptorPool which is overlaid on top of some other pool.
+  // If you search for a descriptor in the overlay and it is not found, the
+  // underlay will be searched as a backup.  If the underlay has its own
+  // underlay, that will be searched next, and so on.  This also means that
+  // files built in the overlay will be cross-linked with the underlay's
+  // descriptors if necessary.  The underlay remains property of the caller;
+  // it must remain valid for the lifetime of the newly-constructed pool.
+  //
+  // Example:  Say you want to parse a .proto file at runtime in order to use
+  // its type with a DynamicMessage.  Say this .proto file has dependencies,
+  // but you know that all the dependencies will be things that are already
+  // compiled into the binary.  For ease of use, you'd like to load the types
+  // right out of generated_pool() rather than have to parse redundant copies
+  // of all these .protos and runtime.  But, you don't want to add the parsed
+  // types directly into generated_pool(): this is not allowed, and would be
+  // bad design anyway.  So, instead, you could use generated_pool() as an
+  // underlay for a new DescriptorPool in which you add only the new file.
+  //
+  // WARNING:  Use of underlays can lead to many subtle gotchas.  Instead,
+  //   try to formulate what you want to do in terms of DescriptorDatabases.
+  explicit DescriptorPool(const DescriptorPool* underlay);
+
+  // Called by generated classes at init time to add their descriptors to
+  // generated_pool.  Do NOT call this in your own code!  filename must be a
+  // permanent string (e.g. a string literal).
+  static void InternalAddGeneratedFile(const void* encoded_file_descriptor,
+                                       int size);
+
+  // Disallow [enforce_utf8 = false] in .proto files.
+  void DisallowEnforceUtf8() { disallow_enforce_utf8_ = true; }
+
+
+  // For internal use only:  Gets a non-const pointer to the generated pool.
+  // This is called at static-initialization time only, so thread-safety is
+  // not a concern.  If both an underlay and a fallback database are present,
+  // the underlay takes precedence.
+  static DescriptorPool* internal_generated_pool();
+
+  // For internal use only:  Changes the behavior of BuildFile() such that it
+  // allows the file to make reference to message types declared in other files
+  // which it did not officially declare as dependencies.
+  void InternalDontEnforceDependencies();
+
+  // For internal use only: Enables lazy building of dependencies of a file.
+  // Delay the building of dependencies of a file descriptor until absolutely
+  // necessary, like when message_type() is called on a field that is defined
+  // in that dependency's file. This will cause functional issues if a proto
+  // or one of it's dependencies has errors. Should only be enabled for the
+  // generated_pool_ (because no descriptor build errors are guaranteed by
+  // the compilation generation process), testing, or if a lack of descriptor
+  // build errors can be guaranteed for a pool.
+  void InternalSetLazilyBuildDependencies() {
+    lazily_build_dependencies_ = true;
+    // This needs to be set when lazily building dependencies, as it breaks
+    // dependency checking.
+    InternalDontEnforceDependencies();
+  }
+
+  // For internal use only.
+  void internal_set_underlay(const DescriptorPool* underlay) {
+    underlay_ = underlay;
+  }
+
+  // For internal (unit test) use only:  Returns true if a FileDescriptor has
+  // been constructed for the given file, false otherwise.  Useful for testing
+  // lazy descriptor initialization behavior.
+  bool InternalIsFileLoaded(const std::string& filename) const;
+
+  // Add a file to unused_import_track_files_. DescriptorBuilder will log
+  // warnings or errors for those files if there is any unused import.
+  void AddUnusedImportTrackFile(const std::string& file_name,
+                                bool is_error = false);
+  void ClearUnusedImportTrackFiles();
+
+ private:
+  friend class Descriptor;
+  friend class internal::LazyDescriptor;
+  friend class FieldDescriptor;
+  friend class EnumDescriptor;
+  friend class ServiceDescriptor;
+  friend class MethodDescriptor;
+  friend class FileDescriptor;
+  friend class StreamDescriptor;
+  friend class DescriptorBuilder;
+  friend class FileDescriptorTables;
+
+  // Return true if the given name is a sub-symbol of any non-package
+  // descriptor that already exists in the descriptor pool.  (The full
+  // definition of such types is already known.)
+  bool IsSubSymbolOfBuiltType(const std::string& name) const;
+
+  // Tries to find something in the fallback database and link in the
+  // corresponding proto file.  Returns true if successful, in which case
+  // the caller should search for the thing again.  These are declared
+  // const because they are called by (semantically) const methods.
+  bool TryFindFileInFallbackDatabase(const std::string& name) const;
+  bool TryFindSymbolInFallbackDatabase(const std::string& name) const;
+  bool TryFindExtensionInFallbackDatabase(const Descriptor* containing_type,
+                                          int field_number) const;
+
+  // This internal find extension method only check with its table and underlay
+  // descriptor_pool's table. It does not check with fallback DB and no
+  // additional proto file will be build in this method.
+  const FieldDescriptor* InternalFindExtensionByNumberNoLock(
+      const Descriptor* extendee, int number) const;
+
+  // Like BuildFile() but called internally when the file has been loaded from
+  // fallback_database_.  Declared const because it is called by (semantically)
+  // const methods.
+  const FileDescriptor* BuildFileFromDatabase(
+      const FileDescriptorProto& proto) const;
+
+  // Helper for when lazily_build_dependencies_ is set, can look up a symbol
+  // after the file's descriptor is built, and can build the file where that
+  // symbol is defined if necessary. Will create a placeholder if the type
+  // doesn't exist in the fallback database, or the file doesn't build
+  // successfully.
+  Symbol CrossLinkOnDemandHelper(const std::string& name,
+                                 bool expecting_enum) const;
+
+  // Create a placeholder FileDescriptor of the specified name
+  FileDescriptor* NewPlaceholderFile(const std::string& name) const;
+  FileDescriptor* NewPlaceholderFileWithMutexHeld(
+      const std::string& name) const;
+
+  enum PlaceholderType {
+    PLACEHOLDER_MESSAGE,
+    PLACEHOLDER_ENUM,
+    PLACEHOLDER_EXTENDABLE_MESSAGE
+  };
+  // Create a placeholder Descriptor of the specified name
+  Symbol NewPlaceholder(const std::string& name,
+                        PlaceholderType placeholder_type) const;
+  Symbol NewPlaceholderWithMutexHeld(const std::string& name,
+                                     PlaceholderType placeholder_type) const;
+
+  // If fallback_database_ is nullptr, this is nullptr.  Otherwise, this is a
+  // mutex which must be locked while accessing tables_.
+  internal::WrappedMutex* mutex_;
+
+  // See constructor.
+  DescriptorDatabase* fallback_database_;
+  ErrorCollector* default_error_collector_;
+  const DescriptorPool* underlay_;
+
+  // This class contains a lot of hash maps with complicated types that
+  // we'd like to keep out of the header.
+  class Tables;
+  std::unique_ptr<Tables> tables_;
+
+  bool enforce_dependencies_;
+  bool lazily_build_dependencies_;
+  bool allow_unknown_;
+  bool enforce_weak_;
+  bool disallow_enforce_utf8_;
+
+  // Set of files to track for unused imports. The bool value when true means
+  // unused imports are treated as errors (and as warnings when false).
+  std::map<std::string, bool> unused_import_track_files_;
+
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(DescriptorPool);
+};
+
+
+// inline methods ====================================================
+
+// These macros makes this repetitive code more readable.
+#define PROTOBUF_DEFINE_ACCESSOR(CLASS, FIELD, TYPE) \
+  inline TYPE CLASS::FIELD() const { return FIELD##_; }
+
+// Strings fields are stored as pointers but returned as const references.
+#define PROTOBUF_DEFINE_STRING_ACCESSOR(CLASS, FIELD) \
+  inline const std::string& CLASS::FIELD() const { return *FIELD##_; }
+
+// Arrays take an index parameter, obviously.
+#define PROTOBUF_DEFINE_ARRAY_ACCESSOR(CLASS, FIELD, TYPE) \
+  inline TYPE CLASS::FIELD(int index) const { return FIELD##s_ + index; }
+
+#define PROTOBUF_DEFINE_OPTIONS_ACCESSOR(CLASS, TYPE) \
+  inline const TYPE& CLASS::options() const { return *options_; }
+
+PROTOBUF_DEFINE_STRING_ACCESSOR(Descriptor, name)
+PROTOBUF_DEFINE_STRING_ACCESSOR(Descriptor, full_name)
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, file, const FileDescriptor*)
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, containing_type, const Descriptor*)
+
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, field_count, int)
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, oneof_decl_count, int)
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, real_oneof_decl_count, int)
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, nested_type_count, int)
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, enum_type_count, int)
+
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(Descriptor, field, const FieldDescriptor*)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(Descriptor, oneof_decl, const OneofDescriptor*)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(Descriptor, nested_type, const Descriptor*)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(Descriptor, enum_type, const EnumDescriptor*)
+
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, extension_range_count, int)
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, extension_count, int)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(Descriptor, extension_range,
+                               const Descriptor::ExtensionRange*)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(Descriptor, extension, const FieldDescriptor*)
+
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, reserved_range_count, int)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(Descriptor, reserved_range,
+                               const Descriptor::ReservedRange*)
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, reserved_name_count, int)
+
+PROTOBUF_DEFINE_OPTIONS_ACCESSOR(Descriptor, MessageOptions)
+PROTOBUF_DEFINE_ACCESSOR(Descriptor, is_placeholder, bool)
+
+PROTOBUF_DEFINE_STRING_ACCESSOR(FieldDescriptor, name)
+PROTOBUF_DEFINE_STRING_ACCESSOR(FieldDescriptor, full_name)
+PROTOBUF_DEFINE_STRING_ACCESSOR(FieldDescriptor, json_name)
+PROTOBUF_DEFINE_STRING_ACCESSOR(FieldDescriptor, lowercase_name)
+PROTOBUF_DEFINE_STRING_ACCESSOR(FieldDescriptor, camelcase_name)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, file, const FileDescriptor*)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, number, int)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, is_extension, bool)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, label, FieldDescriptor::Label)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, containing_type, const Descriptor*)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, containing_oneof,
+                         const OneofDescriptor*)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, index_in_oneof, int)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, extension_scope, const Descriptor*)
+PROTOBUF_DEFINE_OPTIONS_ACCESSOR(FieldDescriptor, FieldOptions)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, has_default_value, bool)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, has_json_name, bool)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, default_value_int32, int32)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, default_value_int64, int64)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, default_value_uint32, uint32)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, default_value_uint64, uint64)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, default_value_float, float)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, default_value_double, double)
+PROTOBUF_DEFINE_ACCESSOR(FieldDescriptor, default_value_bool, bool)
+PROTOBUF_DEFINE_STRING_ACCESSOR(FieldDescriptor, default_value_string)
+
+PROTOBUF_DEFINE_STRING_ACCESSOR(OneofDescriptor, name)
+PROTOBUF_DEFINE_STRING_ACCESSOR(OneofDescriptor, full_name)
+PROTOBUF_DEFINE_ACCESSOR(OneofDescriptor, containing_type, const Descriptor*)
+PROTOBUF_DEFINE_ACCESSOR(OneofDescriptor, field_count, int)
+PROTOBUF_DEFINE_OPTIONS_ACCESSOR(OneofDescriptor, OneofOptions)
+
+PROTOBUF_DEFINE_STRING_ACCESSOR(EnumDescriptor, name)
+PROTOBUF_DEFINE_STRING_ACCESSOR(EnumDescriptor, full_name)
+PROTOBUF_DEFINE_ACCESSOR(EnumDescriptor, file, const FileDescriptor*)
+PROTOBUF_DEFINE_ACCESSOR(EnumDescriptor, containing_type, const Descriptor*)
+PROTOBUF_DEFINE_ACCESSOR(EnumDescriptor, value_count, int)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(EnumDescriptor, value,
+                               const EnumValueDescriptor*)
+PROTOBUF_DEFINE_OPTIONS_ACCESSOR(EnumDescriptor, EnumOptions)
+PROTOBUF_DEFINE_ACCESSOR(EnumDescriptor, is_placeholder, bool)
+PROTOBUF_DEFINE_ACCESSOR(EnumDescriptor, reserved_range_count, int)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(EnumDescriptor, reserved_range,
+                               const EnumDescriptor::ReservedRange*)
+PROTOBUF_DEFINE_ACCESSOR(EnumDescriptor, reserved_name_count, int)
+
+PROTOBUF_DEFINE_STRING_ACCESSOR(EnumValueDescriptor, name)
+PROTOBUF_DEFINE_STRING_ACCESSOR(EnumValueDescriptor, full_name)
+PROTOBUF_DEFINE_ACCESSOR(EnumValueDescriptor, number, int)
+PROTOBUF_DEFINE_ACCESSOR(EnumValueDescriptor, type, const EnumDescriptor*)
+PROTOBUF_DEFINE_OPTIONS_ACCESSOR(EnumValueDescriptor, EnumValueOptions)
+
+PROTOBUF_DEFINE_STRING_ACCESSOR(ServiceDescriptor, name)
+PROTOBUF_DEFINE_STRING_ACCESSOR(ServiceDescriptor, full_name)
+PROTOBUF_DEFINE_ACCESSOR(ServiceDescriptor, file, const FileDescriptor*)
+PROTOBUF_DEFINE_ACCESSOR(ServiceDescriptor, method_count, int)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(ServiceDescriptor, method,
+                               const MethodDescriptor*)
+PROTOBUF_DEFINE_OPTIONS_ACCESSOR(ServiceDescriptor, ServiceOptions)
+
+PROTOBUF_DEFINE_STRING_ACCESSOR(MethodDescriptor, name)
+PROTOBUF_DEFINE_STRING_ACCESSOR(MethodDescriptor, full_name)
+PROTOBUF_DEFINE_ACCESSOR(MethodDescriptor, service, const ServiceDescriptor*)
+PROTOBUF_DEFINE_OPTIONS_ACCESSOR(MethodDescriptor, MethodOptions)
+PROTOBUF_DEFINE_ACCESSOR(MethodDescriptor, client_streaming, bool)
+PROTOBUF_DEFINE_ACCESSOR(MethodDescriptor, server_streaming, bool)
+
+PROTOBUF_DEFINE_STRING_ACCESSOR(FileDescriptor, name)
+PROTOBUF_DEFINE_STRING_ACCESSOR(FileDescriptor, package)
+PROTOBUF_DEFINE_ACCESSOR(FileDescriptor, pool, const DescriptorPool*)
+PROTOBUF_DEFINE_ACCESSOR(FileDescriptor, dependency_count, int)
+PROTOBUF_DEFINE_ACCESSOR(FileDescriptor, public_dependency_count, int)
+PROTOBUF_DEFINE_ACCESSOR(FileDescriptor, weak_dependency_count, int)
+PROTOBUF_DEFINE_ACCESSOR(FileDescriptor, message_type_count, int)
+PROTOBUF_DEFINE_ACCESSOR(FileDescriptor, enum_type_count, int)
+PROTOBUF_DEFINE_ACCESSOR(FileDescriptor, service_count, int)
+PROTOBUF_DEFINE_ACCESSOR(FileDescriptor, extension_count, int)
+PROTOBUF_DEFINE_OPTIONS_ACCESSOR(FileDescriptor, FileOptions)
+PROTOBUF_DEFINE_ACCESSOR(FileDescriptor, is_placeholder, bool)
+
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(FileDescriptor, message_type, const Descriptor*)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(FileDescriptor, enum_type, const EnumDescriptor*)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(FileDescriptor, service,
+                               const ServiceDescriptor*)
+PROTOBUF_DEFINE_ARRAY_ACCESSOR(FileDescriptor, extension,
+                               const FieldDescriptor*)
+
+#undef PROTOBUF_DEFINE_ACCESSOR
+#undef PROTOBUF_DEFINE_STRING_ACCESSOR
+#undef PROTOBUF_DEFINE_ARRAY_ACCESSOR
+
+// A few accessors differ from the macros...
+
+inline Descriptor::WellKnownType Descriptor::well_known_type() const {
+  return static_cast<Descriptor::WellKnownType>(well_known_type_);
+}
+
+inline bool Descriptor::IsExtensionNumber(int number) const {
+  return FindExtensionRangeContainingNumber(number) != nullptr;
+}
+
+inline bool Descriptor::IsReservedNumber(int number) const {
+  return FindReservedRangeContainingNumber(number) != nullptr;
+}
+
+inline bool Descriptor::IsReservedName(const std::string& name) const {
+  for (int i = 0; i < reserved_name_count(); i++) {
+    if (name == reserved_name(i)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+// Can't use PROTOBUF_DEFINE_ARRAY_ACCESSOR because reserved_names_ is actually
+// an array of pointers rather than the usual array of objects.
+inline const std::string& Descriptor::reserved_name(int index) const {
+  return *reserved_names_[index];
+}
+
+inline bool EnumDescriptor::IsReservedNumber(int number) const {
+  return FindReservedRangeContainingNumber(number) != nullptr;
+}
+
+inline bool EnumDescriptor::IsReservedName(const std::string& name) const {
+  for (int i = 0; i < reserved_name_count(); i++) {
+    if (name == reserved_name(i)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+// Can't use PROTOBUF_DEFINE_ARRAY_ACCESSOR because reserved_names_ is actually
+// an array of pointers rather than the usual array of objects.
+inline const std::string& EnumDescriptor::reserved_name(int index) const {
+  return *reserved_names_[index];
+}
+
+inline FieldDescriptor::Type FieldDescriptor::type() const {
+  if (type_once_) {
+    internal::call_once(*type_once_, &FieldDescriptor::TypeOnceInit, this);
+  }
+  return type_;
+}
+
+inline bool FieldDescriptor::is_required() const {
+  return label() == LABEL_REQUIRED;
+}
+
+inline bool FieldDescriptor::is_optional() const {
+  return label() == LABEL_OPTIONAL;
+}
+
+inline bool FieldDescriptor::is_repeated() const {
+  return label() == LABEL_REPEATED;
+}
+
+inline bool FieldDescriptor::is_packable() const {
+  return is_repeated() && IsTypePackable(type());
+}
+
+inline bool FieldDescriptor::is_map() const {
+  return type() == TYPE_MESSAGE && is_map_message_type();
+}
+
+inline bool FieldDescriptor::has_optional_keyword() const {
+  return proto3_optional_ ||
+         (file()->syntax() == FileDescriptor::SYNTAX_PROTO2 && is_optional() &&
+          !containing_oneof());
+}
+
+inline const OneofDescriptor* FieldDescriptor::real_containing_oneof() const {
+  return containing_oneof_ && !containing_oneof_->is_synthetic()
+             ? containing_oneof_
+             : nullptr;
+}
+
+inline bool FieldDescriptor::has_presence() const {
+  if (is_repeated()) return false;
+  return cpp_type() == CPPTYPE_MESSAGE || containing_oneof() ||
+         file()->syntax() == FileDescriptor::SYNTAX_PROTO2;
+}
+
+// To save space, index() is computed by looking at the descriptor's position
+// in the parent's array of children.
+inline int FieldDescriptor::index() const {
+  if (!is_extension_) {
+    return static_cast<int>(this - containing_type()->fields_);
+  } else if (extension_scope_ != nullptr) {
+    return static_cast<int>(this - extension_scope_->extensions_);
+  } else {
+    return static_cast<int>(this - file_->extensions_);
+  }
+}
+
+inline int Descriptor::index() const {
+  if (containing_type_ == nullptr) {
+    return static_cast<int>(this - file_->message_types_);
+  } else {
+    return static_cast<int>(this - containing_type_->nested_types_);
+  }
+}
+
+inline const FileDescriptor* OneofDescriptor::file() const {
+  return containing_type()->file();
+}
+
+inline int OneofDescriptor::index() const {
+  return static_cast<int>(this - containing_type_->oneof_decls_);
+}
+
+inline bool OneofDescriptor::is_synthetic() const {
+  return field_count() == 1 && field(0)->proto3_optional_;
+}
+
+inline int EnumDescriptor::index() const {
+  if (containing_type_ == nullptr) {
+    return static_cast<int>(this - file_->enum_types_);
+  } else {
+    return static_cast<int>(this - containing_type_->enum_types_);
+  }
+}
+
+inline const FileDescriptor* EnumValueDescriptor::file() const {
+  return type()->file();
+}
+
+inline int EnumValueDescriptor::index() const {
+  return static_cast<int>(this - type_->values_);
+}
+
+inline int ServiceDescriptor::index() const {
+  return static_cast<int>(this - file_->services_);
+}
+
+inline const FileDescriptor* MethodDescriptor::file() const {
+  return service()->file();
+}
+
+inline int MethodDescriptor::index() const {
+  return static_cast<int>(this - service_->methods_);
+}
+
+inline const char* FieldDescriptor::type_name() const {
+  return kTypeToName[type()];
+}
+
+inline FieldDescriptor::CppType FieldDescriptor::cpp_type() const {
+  return kTypeToCppTypeMap[type()];
+}
+
+inline const char* FieldDescriptor::cpp_type_name() const {
+  return kCppTypeToName[kTypeToCppTypeMap[type()]];
+}
+
+inline FieldDescriptor::CppType FieldDescriptor::TypeToCppType(Type type) {
+  return kTypeToCppTypeMap[type];
+}
+
+inline const char* FieldDescriptor::TypeName(Type type) {
+  return kTypeToName[type];
+}
+
+inline const char* FieldDescriptor::CppTypeName(CppType cpp_type) {
+  return kCppTypeToName[cpp_type];
+}
+
+inline bool FieldDescriptor::IsTypePackable(Type field_type) {
+  return (field_type != FieldDescriptor::TYPE_STRING &&
+          field_type != FieldDescriptor::TYPE_GROUP &&
+          field_type != FieldDescriptor::TYPE_MESSAGE &&
+          field_type != FieldDescriptor::TYPE_BYTES);
+}
+
+inline const FileDescriptor* FileDescriptor::public_dependency(
+    int index) const {
+  return dependency(public_dependencies_[index]);
+}
+
+inline const FileDescriptor* FileDescriptor::weak_dependency(int index) const {
+  return dependency(weak_dependencies_[index]);
+}
+
+inline FileDescriptor::Syntax FileDescriptor::syntax() const { return syntax_; }
+
+// Can't use PROTOBUF_DEFINE_ARRAY_ACCESSOR because fields_ is actually an array
+// of pointers rather than the usual array of objects.
+inline const FieldDescriptor* OneofDescriptor::field(int index) const {
+  return fields_[index];
+}
+
+}  // namespace protobuf
+}  // namespace google
+
+#include <google/protobuf/port_undef.inc>
+
+#endif  // GOOGLE_PROTOBUF_DESCRIPTOR_H__
diff --git a/third_party/protobuf-lite/google/protobuf/generated_enum_reflection.h b/third_party/protobuf-lite/google/protobuf/generated_enum_reflection.h
new file mode 100644
index 0000000..c25e51b
--- /dev/null
+++ b/third_party/protobuf-lite/google/protobuf/generated_enum_reflection.h
@@ -0,0 +1,97 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: jasonh@google.com (Jason Hsueh)
+//
+// This header is logically internal, but is made public because it is used
+// from protocol-compiler-generated code, which may reside in other components.
+// It provides reflection support for generated enums, and is included in
+// generated .pb.h files and should have minimal dependencies. The methods are
+// implemented in generated_message_reflection.cc.
+
+#ifndef GOOGLE_PROTOBUF_GENERATED_ENUM_REFLECTION_H__
+#define GOOGLE_PROTOBUF_GENERATED_ENUM_REFLECTION_H__
+
+#include <string>
+
+#include <google/protobuf/generated_enum_util.h>
+#include <google/protobuf/port.h>
+
+#ifdef SWIG
+#error "You cannot SWIG proto headers"
+#endif
+
+#include <google/protobuf/port_def.inc>
+
+namespace google {
+namespace protobuf {
+class EnumDescriptor;
+}  // namespace protobuf
+}  // namespace google
+
+namespace google {
+namespace protobuf {
+
+// Returns the EnumDescriptor for enum type E, which must be a
+// proto-declared enum type.  Code generated by the protocol compiler
+// will include specializations of this template for each enum type declared.
+template <typename E>
+const EnumDescriptor* GetEnumDescriptor();
+
+namespace internal {
+
+// Helper for EnumType_Parse functions: try to parse the string 'name' as
+// an enum name of the given type, returning true and filling in value on
+// success, or returning false and leaving value unchanged on failure.
+PROTOBUF_EXPORT bool ParseNamedEnum(const EnumDescriptor* descriptor,
+                                    const std::string& name, int* value);
+
+template <typename EnumType>
+bool ParseNamedEnum(const EnumDescriptor* descriptor, const std::string& name,
+                    EnumType* value) {
+  int tmp;
+  if (!ParseNamedEnum(descriptor, name, &tmp)) return false;
+  *value = static_cast<EnumType>(tmp);
+  return true;
+}
+
+// Just a wrapper around printing the name of a value. The main point of this
+// function is not to be inlined, so that you can do this without including
+// descriptor.h.
+PROTOBUF_EXPORT const std::string& NameOfEnum(const EnumDescriptor* descriptor,
+                                              int value);
+
+}  // namespace internal
+}  // namespace protobuf
+}  // namespace google
+
+#include <google/protobuf/port_undef.inc>
+
+#endif  // GOOGLE_PROTOBUF_GENERATED_ENUM_REFLECTION_H__
diff --git a/third_party/protobuf-lite/google/protobuf/io/zero_copy_stream_impl.h b/third_party/protobuf-lite/google/protobuf/io/zero_copy_stream_impl.h
new file mode 100644
index 0000000..b23a86d
--- /dev/null
+++ b/third_party/protobuf-lite/google/protobuf/io/zero_copy_stream_impl.h
@@ -0,0 +1,338 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: kenton@google.com (Kenton Varda)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+//
+// This file contains common implementations of the interfaces defined in
+// zero_copy_stream.h which are only included in the full (non-lite)
+// protobuf library.  These implementations include Unix file descriptors
+// and C++ iostreams.  See also:  zero_copy_stream_impl_lite.h
+
+#ifndef GOOGLE_PROTOBUF_IO_ZERO_COPY_STREAM_IMPL_H__
+#define GOOGLE_PROTOBUF_IO_ZERO_COPY_STREAM_IMPL_H__
+
+
+#include <iosfwd>
+#include <string>
+
+#include <google/protobuf/stubs/common.h>
+#include <google/protobuf/io/zero_copy_stream.h>
+#include <google/protobuf/io/zero_copy_stream_impl_lite.h>
+
+
+#include <google/protobuf/port_def.inc>
+
+namespace google {
+namespace protobuf {
+namespace io {
+
+// ===================================================================
+
+// A ZeroCopyInputStream which reads from a file descriptor.
+//
+// FileInputStream is preferred over using an ifstream with IstreamInputStream.
+// The latter will introduce an extra layer of buffering, harming performance.
+// Also, it's conceivable that FileInputStream could someday be enhanced
+// to use zero-copy file descriptors on OSs which support them.
+class PROTOBUF_EXPORT FileInputStream : public ZeroCopyInputStream {
+ public:
+  // Creates a stream that reads from the given Unix file descriptor.
+  // If a block_size is given, it specifies the number of bytes that
+  // should be read and returned with each call to Next().  Otherwise,
+  // a reasonable default is used.
+  explicit FileInputStream(int file_descriptor, int block_size = -1);
+
+  // Flushes any buffers and closes the underlying file.  Returns false if
+  // an error occurs during the process; use GetErrno() to examine the error.
+  // Even if an error occurs, the file descriptor is closed when this returns.
+  bool Close();
+
+  // By default, the file descriptor is not closed when the stream is
+  // destroyed.  Call SetCloseOnDelete(true) to change that.  WARNING:
+  // This leaves no way for the caller to detect if close() fails.  If
+  // detecting close() errors is important to you, you should arrange
+  // to close the descriptor yourself.
+  void SetCloseOnDelete(bool value) { copying_input_.SetCloseOnDelete(value); }
+
+  // If an I/O error has occurred on this file descriptor, this is the
+  // errno from that error.  Otherwise, this is zero.  Once an error
+  // occurs, the stream is broken and all subsequent operations will
+  // fail.
+  int GetErrno() const { return copying_input_.GetErrno(); }
+
+  // implements ZeroCopyInputStream ----------------------------------
+  bool Next(const void** data, int* size) override;
+  void BackUp(int count) override;
+  bool Skip(int count) override;
+  int64_t ByteCount() const override;
+
+ private:
+  class PROTOBUF_EXPORT CopyingFileInputStream : public CopyingInputStream {
+   public:
+    CopyingFileInputStream(int file_descriptor);
+    ~CopyingFileInputStream() override;
+
+    bool Close();
+    void SetCloseOnDelete(bool value) { close_on_delete_ = value; }
+    int GetErrno() const { return errno_; }
+
+    // implements CopyingInputStream ---------------------------------
+    int Read(void* buffer, int size) override;
+    int Skip(int count) override;
+
+   private:
+    // The file descriptor.
+    const int file_;
+    bool close_on_delete_;
+    bool is_closed_;
+
+    // The errno of the I/O error, if one has occurred.  Otherwise, zero.
+    int errno_;
+
+    // Did we try to seek once and fail?  If so, we assume this file descriptor
+    // doesn't support seeking and won't try again.
+    bool previous_seek_failed_;
+
+    GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CopyingFileInputStream);
+  };
+
+  CopyingFileInputStream copying_input_;
+  CopyingInputStreamAdaptor impl_;
+
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FileInputStream);
+};
+
+// ===================================================================
+
+// A ZeroCopyOutputStream which writes to a file descriptor.
+//
+// FileOutputStream is preferred over using an ofstream with
+// OstreamOutputStream.  The latter will introduce an extra layer of buffering,
+// harming performance.  Also, it's conceivable that FileOutputStream could
+// someday be enhanced to use zero-copy file descriptors on OSs which
+// support them.
+class PROTOBUF_EXPORT FileOutputStream : public ZeroCopyOutputStream {
+ public:
+  // Creates a stream that writes to the given Unix file descriptor.
+  // If a block_size is given, it specifies the size of the buffers
+  // that should be returned by Next().  Otherwise, a reasonable default
+  // is used.
+  explicit FileOutputStream(int file_descriptor, int block_size = -1);
+  ~FileOutputStream() override;
+
+  // Flushes any buffers and closes the underlying file.  Returns false if
+  // an error occurs during the process; use GetErrno() to examine the error.
+  // Even if an error occurs, the file descriptor is closed when this returns.
+  bool Close();
+
+  // Flushes FileOutputStream's buffers but does not close the
+  // underlying file. No special measures are taken to ensure that
+  // underlying operating system file object is synchronized to disk.
+  bool Flush();
+
+  // By default, the file descriptor is not closed when the stream is
+  // destroyed.  Call SetCloseOnDelete(true) to change that.  WARNING:
+  // This leaves no way for the caller to detect if close() fails.  If
+  // detecting close() errors is important to you, you should arrange
+  // to close the descriptor yourself.
+  void SetCloseOnDelete(bool value) { copying_output_.SetCloseOnDelete(value); }
+
+  // If an I/O error has occurred on this file descriptor, this is the
+  // errno from that error.  Otherwise, this is zero.  Once an error
+  // occurs, the stream is broken and all subsequent operations will
+  // fail.
+  int GetErrno() const { return copying_output_.GetErrno(); }
+
+  // implements ZeroCopyOutputStream ---------------------------------
+  bool Next(void** data, int* size) override;
+  void BackUp(int count) override;
+  int64_t ByteCount() const override;
+
+ private:
+  class PROTOBUF_EXPORT CopyingFileOutputStream : public CopyingOutputStream {
+   public:
+    CopyingFileOutputStream(int file_descriptor);
+    ~CopyingFileOutputStream() override;
+
+    bool Close();
+    void SetCloseOnDelete(bool value) { close_on_delete_ = value; }
+    int GetErrno() const { return errno_; }
+
+    // implements CopyingOutputStream --------------------------------
+    bool Write(const void* buffer, int size) override;
+
+   private:
+    // The file descriptor.
+    const int file_;
+    bool close_on_delete_;
+    bool is_closed_;
+
+    // The errno of the I/O error, if one has occurred.  Otherwise, zero.
+    int errno_;
+
+    GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CopyingFileOutputStream);
+  };
+
+  CopyingFileOutputStream copying_output_;
+  CopyingOutputStreamAdaptor impl_;
+
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FileOutputStream);
+};
+
+// ===================================================================
+
+// A ZeroCopyInputStream which reads from a C++ istream.
+//
+// Note that for reading files (or anything represented by a file descriptor),
+// FileInputStream is more efficient.
+class PROTOBUF_EXPORT IstreamInputStream : public ZeroCopyInputStream {
+ public:
+  // Creates a stream that reads from the given C++ istream.
+  // If a block_size is given, it specifies the number of bytes that
+  // should be read and returned with each call to Next().  Otherwise,
+  // a reasonable default is used.
+  explicit IstreamInputStream(std::istream* stream, int block_size = -1);
+
+  // implements ZeroCopyInputStream ----------------------------------
+  bool Next(const void** data, int* size) override;
+  void BackUp(int count) override;
+  bool Skip(int count) override;
+  int64_t ByteCount() const override;
+
+ private:
+  class PROTOBUF_EXPORT CopyingIstreamInputStream : public CopyingInputStream {
+   public:
+    CopyingIstreamInputStream(std::istream* input);
+    ~CopyingIstreamInputStream() override;
+
+    // implements CopyingInputStream ---------------------------------
+    int Read(void* buffer, int size) override;
+    // (We use the default implementation of Skip().)
+
+   private:
+    // The stream.
+    std::istream* input_;
+
+    GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CopyingIstreamInputStream);
+  };
+
+  CopyingIstreamInputStream copying_input_;
+  CopyingInputStreamAdaptor impl_;
+
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(IstreamInputStream);
+};
+
+// ===================================================================
+
+// A ZeroCopyOutputStream which writes to a C++ ostream.
+//
+// Note that for writing files (or anything represented by a file descriptor),
+// FileOutputStream is more efficient.
+class PROTOBUF_EXPORT OstreamOutputStream : public ZeroCopyOutputStream {
+ public:
+  // Creates a stream that writes to the given C++ ostream.
+  // If a block_size is given, it specifies the size of the buffers
+  // that should be returned by Next().  Otherwise, a reasonable default
+  // is used.
+  explicit OstreamOutputStream(std::ostream* stream, int block_size = -1);
+  ~OstreamOutputStream() override;
+
+  // implements ZeroCopyOutputStream ---------------------------------
+  bool Next(void** data, int* size) override;
+  void BackUp(int count) override;
+  int64_t ByteCount() const override;
+
+ private:
+  class PROTOBUF_EXPORT CopyingOstreamOutputStream
+      : public CopyingOutputStream {
+   public:
+    CopyingOstreamOutputStream(std::ostream* output);
+    ~CopyingOstreamOutputStream() override;
+
+    // implements CopyingOutputStream --------------------------------
+    bool Write(const void* buffer, int size) override;
+
+   private:
+    // The stream.
+    std::ostream* output_;
+
+    GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CopyingOstreamOutputStream);
+  };
+
+  CopyingOstreamOutputStream copying_output_;
+  CopyingOutputStreamAdaptor impl_;
+
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(OstreamOutputStream);
+};
+
+// ===================================================================
+
+// A ZeroCopyInputStream which reads from several other streams in sequence.
+// ConcatenatingInputStream is unable to distinguish between end-of-stream
+// and read errors in the underlying streams, so it assumes any errors mean
+// end-of-stream.  So, if the underlying streams fail for any other reason,
+// ConcatenatingInputStream may do odd things.  It is suggested that you do
+// not use ConcatenatingInputStream on streams that might produce read errors
+// other than end-of-stream.
+class PROTOBUF_EXPORT ConcatenatingInputStream : public ZeroCopyInputStream {
+ public:
+  // All streams passed in as well as the array itself must remain valid
+  // until the ConcatenatingInputStream is destroyed.
+  ConcatenatingInputStream(ZeroCopyInputStream* const streams[], int count);
+  ~ConcatenatingInputStream() override = default;
+
+  // implements ZeroCopyInputStream ----------------------------------
+  bool Next(const void** data, int* size) override;
+  void BackUp(int count) override;
+  bool Skip(int count) override;
+  int64_t ByteCount() const override;
+
+
+ private:
+  // As streams are retired, streams_ is incremented and count_ is
+  // decremented.
+  ZeroCopyInputStream* const* streams_;
+  int stream_count_;
+  int64 bytes_retired_;  // Bytes read from previous streams.
+
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ConcatenatingInputStream);
+};
+
+// ===================================================================
+
+}  // namespace io
+}  // namespace protobuf
+}  // namespace google
+
+#include <google/protobuf/port_undef.inc>
+
+#endif  // GOOGLE_PROTOBUF_IO_ZERO_COPY_STREAM_IMPL_H__
diff --git a/third_party/protobuf-lite/google/protobuf/unknown_field_set.h b/third_party/protobuf-lite/google/protobuf/unknown_field_set.h
new file mode 100644
index 0000000..ab3633d
--- /dev/null
+++ b/third_party/protobuf-lite/google/protobuf/unknown_field_set.h
@@ -0,0 +1,411 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: kenton@google.com (Kenton Varda)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+//
+// Contains classes used to keep track of unrecognized fields seen while
+// parsing a protocol message.
+
+#ifndef GOOGLE_PROTOBUF_UNKNOWN_FIELD_SET_H__
+#define GOOGLE_PROTOBUF_UNKNOWN_FIELD_SET_H__
+
+#include <assert.h>
+
+#include <string>
+#include <vector>
+
+#include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/logging.h>
+#include <google/protobuf/parse_context.h>
+#include <google/protobuf/io/coded_stream.h>
+#include <google/protobuf/io/zero_copy_stream_impl_lite.h>
+#include <google/protobuf/message_lite.h>
+#include <google/protobuf/port.h>
+
+#include <google/protobuf/port_def.inc>
+
+#ifdef SWIG
+#error "You cannot SWIG proto headers"
+#endif
+
+namespace google {
+namespace protobuf {
+namespace internal {
+class InternalMetadata;           // metadata_lite.h
+class WireFormat;                 // wire_format.h
+class MessageSetFieldSkipperUsingCord;
+// extension_set_heavy.cc
+}  // namespace internal
+
+class Message;       // message.h
+class UnknownField;  // below
+
+// An UnknownFieldSet contains fields that were encountered while parsing a
+// message but were not defined by its type.  Keeping track of these can be
+// useful, especially in that they may be written if the message is serialized
+// again without being cleared in between.  This means that software which
+// simply receives messages and forwards them to other servers does not need
+// to be updated every time a new field is added to the message definition.
+//
+// To get the UnknownFieldSet attached to any message, call
+// Reflection::GetUnknownFields().
+//
+// This class is necessarily tied to the protocol buffer wire format, unlike
+// the Reflection interface which is independent of any serialization scheme.
+class PROTOBUF_EXPORT UnknownFieldSet {
+ public:
+  UnknownFieldSet();
+  ~UnknownFieldSet();
+
+  // Remove all fields.
+  inline void Clear();
+
+  // Remove all fields and deallocate internal data objects
+  void ClearAndFreeMemory();
+
+  // Is this set empty?
+  inline bool empty() const;
+
+  // Merge the contents of some other UnknownFieldSet with this one.
+  void MergeFrom(const UnknownFieldSet& other);
+
+  // Similar to above, but this function will destroy the contents of other.
+  void MergeFromAndDestroy(UnknownFieldSet* other);
+
+  // Merge the contents an UnknownFieldSet with the UnknownFieldSet in
+  // *metadata, if there is one.  If *metadata doesn't have an UnknownFieldSet
+  // then add one to it and make it be a copy of the first arg.
+  static void MergeToInternalMetadata(const UnknownFieldSet& other,
+                                      internal::InternalMetadata* metadata);
+
+  // Swaps the contents of some other UnknownFieldSet with this one.
+  inline void Swap(UnknownFieldSet* x);
+
+  // Computes (an estimate of) the total number of bytes currently used for
+  // storing the unknown fields in memory. Does NOT include
+  // sizeof(*this) in the calculation.
+  size_t SpaceUsedExcludingSelfLong() const;
+
+  int SpaceUsedExcludingSelf() const {
+    return internal::ToIntSize(SpaceUsedExcludingSelfLong());
+  }
+
+  // Version of SpaceUsed() including sizeof(*this).
+  size_t SpaceUsedLong() const;
+
+  int SpaceUsed() const { return internal::ToIntSize(SpaceUsedLong()); }
+
+  // Returns the number of fields present in the UnknownFieldSet.
+  inline int field_count() const;
+  // Get a field in the set, where 0 <= index < field_count().  The fields
+  // appear in the order in which they were added.
+  inline const UnknownField& field(int index) const;
+  // Get a mutable pointer to a field in the set, where
+  // 0 <= index < field_count().  The fields appear in the order in which
+  // they were added.
+  inline UnknownField* mutable_field(int index);
+
+  // Adding fields ---------------------------------------------------
+
+  void AddVarint(int number, uint64 value);
+  void AddFixed32(int number, uint32 value);
+  void AddFixed64(int number, uint64 value);
+  void AddLengthDelimited(int number, const std::string& value);
+  std::string* AddLengthDelimited(int number);
+  UnknownFieldSet* AddGroup(int number);
+
+  // Adds an unknown field from another set.
+  void AddField(const UnknownField& field);
+
+  // Delete fields with indices in the range [start .. start+num-1].
+  // Caution: implementation moves all fields with indices [start+num .. ].
+  void DeleteSubrange(int start, int num);
+
+  // Delete all fields with a specific field number. The order of left fields
+  // is preserved.
+  // Caution: implementation moves all fields after the first deleted field.
+  void DeleteByNumber(int number);
+
+  // Parsing helpers -------------------------------------------------
+  // These work exactly like the similarly-named methods of Message.
+
+  bool MergeFromCodedStream(io::CodedInputStream* input);
+  bool ParseFromCodedStream(io::CodedInputStream* input);
+  bool ParseFromZeroCopyStream(io::ZeroCopyInputStream* input);
+  bool ParseFromArray(const void* data, int size);
+  inline bool ParseFromString(const std::string& data) {
+    return ParseFromArray(data.data(), static_cast<int>(data.size()));
+  }
+
+  // Merges this message's unknown field data (if any).  This works whether
+  // the message is a lite or full proto (for legacy reasons, lite and full
+  // return different types for MessageType::unknown_fields()).
+  template <typename MessageType>
+  bool MergeFromMessage(const MessageType& message);
+
+  static const UnknownFieldSet& default_instance();
+
+ private:
+  // For InternalMergeFrom
+  friend class UnknownField;
+  // Merges from other UnknownFieldSet. This method assumes, that this object
+  // is newly created and has no fields.
+  void InternalMergeFrom(const UnknownFieldSet& other);
+  void ClearFallback();
+
+  template <typename MessageType,
+            typename std::enable_if<
+                std::is_base_of<Message, MessageType>::value, int>::type = 0>
+  bool InternalMergeFromMessage(const MessageType& message) {
+    MergeFrom(message.GetReflection()->GetUnknownFields(message));
+    return true;
+  }
+
+  template <typename MessageType,
+            typename std::enable_if<
+                std::is_base_of<MessageLite, MessageType>::value &&
+                    !std::is_base_of<Message, MessageType>::value,
+                int>::type = 0>
+  bool InternalMergeFromMessage(const MessageType& message) {
+    const auto& unknown_fields = message.unknown_fields();
+    io::ArrayInputStream array_stream(unknown_fields.data(),
+                                      unknown_fields.size());
+    io::CodedInputStream coded_stream(&array_stream);
+    return MergeFromCodedStream(&coded_stream);
+  }
+
+  std::vector<UnknownField> fields_;
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(UnknownFieldSet);
+};
+
+namespace internal {
+
+inline void WriteVarint(uint32 num, uint64 val, UnknownFieldSet* unknown) {
+  unknown->AddVarint(num, val);
+}
+inline void WriteLengthDelimited(uint32 num, StringPiece val,
+                                 UnknownFieldSet* unknown) {
+  unknown->AddLengthDelimited(num)->assign(val.data(), val.size());
+}
+
+PROTOBUF_EXPORT
+const char* UnknownGroupParse(UnknownFieldSet* unknown, const char* ptr,
+                              ParseContext* ctx);
+PROTOBUF_EXPORT
+const char* UnknownFieldParse(uint64 tag, UnknownFieldSet* unknown,
+                              const char* ptr, ParseContext* ctx);
+
+}  // namespace internal
+
+// Represents one field in an UnknownFieldSet.
+class PROTOBUF_EXPORT UnknownField {
+ public:
+  enum Type {
+    TYPE_VARINT,
+    TYPE_FIXED32,
+    TYPE_FIXED64,
+    TYPE_LENGTH_DELIMITED,
+    TYPE_GROUP
+  };
+
+  // The field's field number, as seen on the wire.
+  inline int number() const;
+
+  // The field type.
+  inline Type type() const;
+
+  // Accessors -------------------------------------------------------
+  // Each method works only for UnknownFields of the corresponding type.
+
+  inline uint64 varint() const;
+  inline uint32 fixed32() const;
+  inline uint64 fixed64() const;
+  inline const std::string& length_delimited() const;
+  inline const UnknownFieldSet& group() const;
+
+  inline void set_varint(uint64 value);
+  inline void set_fixed32(uint32 value);
+  inline void set_fixed64(uint64 value);
+  inline void set_length_delimited(const std::string& value);
+  inline std::string* mutable_length_delimited();
+  inline UnknownFieldSet* mutable_group();
+
+  // Serialization API.
+  // These methods can take advantage of the underlying implementation and may
+  // archieve a better performance than using getters to retrieve the data and
+  // do the serialization yourself.
+  void SerializeLengthDelimitedNoTag(io::CodedOutputStream* output) const {
+    output->SetCur(InternalSerializeLengthDelimitedNoTag(output->Cur(),
+                                                         output->EpsCopy()));
+  }
+
+  inline size_t GetLengthDelimitedSize() const;
+  uint8* InternalSerializeLengthDelimitedNoTag(
+      uint8* target, io::EpsCopyOutputStream* stream) const;
+
+
+  // If this UnknownField contains a pointer, delete it.
+  void Delete();
+
+  // Make a deep copy of any pointers in this UnknownField.
+  void DeepCopy(const UnknownField& other);
+
+  // Set the wire type of this UnknownField. Should only be used when this
+  // UnknownField is being created.
+  inline void SetType(Type type);
+
+  union LengthDelimited {
+    std::string* string_value;
+  };
+
+  uint32 number_;
+  uint32 type_;
+  union {
+    uint64 varint_;
+    uint32 fixed32_;
+    uint64 fixed64_;
+    mutable union LengthDelimited length_delimited_;
+    UnknownFieldSet* group_;
+  } data_;
+};
+
+// ===================================================================
+// inline implementations
+
+inline UnknownFieldSet::UnknownFieldSet() {}
+
+inline UnknownFieldSet::~UnknownFieldSet() { Clear(); }
+
+inline void UnknownFieldSet::ClearAndFreeMemory() { Clear(); }
+
+inline void UnknownFieldSet::Clear() {
+  if (!fields_.empty()) {
+    ClearFallback();
+  }
+}
+
+inline bool UnknownFieldSet::empty() const { return fields_.empty(); }
+
+inline void UnknownFieldSet::Swap(UnknownFieldSet* x) {
+  fields_.swap(x->fields_);
+}
+
+inline int UnknownFieldSet::field_count() const {
+  return static_cast<int>(fields_.size());
+}
+inline const UnknownField& UnknownFieldSet::field(int index) const {
+  return (fields_)[static_cast<size_t>(index)];
+}
+inline UnknownField* UnknownFieldSet::mutable_field(int index) {
+  return &(fields_)[static_cast<size_t>(index)];
+}
+
+inline void UnknownFieldSet::AddLengthDelimited(int number,
+                                                const std::string& value) {
+  AddLengthDelimited(number)->assign(value);
+}
+
+
+
+
+inline int UnknownField::number() const { return static_cast<int>(number_); }
+inline UnknownField::Type UnknownField::type() const {
+  return static_cast<Type>(type_);
+}
+
+inline uint64 UnknownField::varint() const {
+  assert(type() == TYPE_VARINT);
+  return data_.varint_;
+}
+inline uint32 UnknownField::fixed32() const {
+  assert(type() == TYPE_FIXED32);
+  return data_.fixed32_;
+}
+inline uint64 UnknownField::fixed64() const {
+  assert(type() == TYPE_FIXED64);
+  return data_.fixed64_;
+}
+inline const std::string& UnknownField::length_delimited() const {
+  assert(type() == TYPE_LENGTH_DELIMITED);
+  return *data_.length_delimited_.string_value;
+}
+inline const UnknownFieldSet& UnknownField::group() const {
+  assert(type() == TYPE_GROUP);
+  return *data_.group_;
+}
+
+inline void UnknownField::set_varint(uint64 value) {
+  assert(type() == TYPE_VARINT);
+  data_.varint_ = value;
+}
+inline void UnknownField::set_fixed32(uint32 value) {
+  assert(type() == TYPE_FIXED32);
+  data_.fixed32_ = value;
+}
+inline void UnknownField::set_fixed64(uint64 value) {
+  assert(type() == TYPE_FIXED64);
+  data_.fixed64_ = value;
+}
+inline void UnknownField::set_length_delimited(const std::string& value) {
+  assert(type() == TYPE_LENGTH_DELIMITED);
+  data_.length_delimited_.string_value->assign(value);
+}
+inline std::string* UnknownField::mutable_length_delimited() {
+  assert(type() == TYPE_LENGTH_DELIMITED);
+  return data_.length_delimited_.string_value;
+}
+inline UnknownFieldSet* UnknownField::mutable_group() {
+  assert(type() == TYPE_GROUP);
+  return data_.group_;
+}
+template <typename MessageType>
+bool UnknownFieldSet::MergeFromMessage(const MessageType& message) {
+  // SFINAE will route to the right version.
+  return InternalMergeFromMessage(message);
+}
+
+
+inline size_t UnknownField::GetLengthDelimitedSize() const {
+  GOOGLE_DCHECK_EQ(TYPE_LENGTH_DELIMITED, type());
+  return data_.length_delimited_.string_value->size();
+}
+
+inline void UnknownField::SetType(Type type) {
+  type_ = type;
+}
+
+
+}  // namespace protobuf
+}  // namespace google
+
+#include <google/protobuf/port_undef.inc>
+#endif  // GOOGLE_PROTOBUF_UNKNOWN_FIELD_SET_H__