n-api: add support for abi stable module API

Add support for abi stable module API (N-API) as "Experimental feature".
The goal of this API is to provide a stable Node API for native
module developers. N-API aims to provide ABI compatibility guarantees
across different Node versions and also across different
Node VMs - allowing N-API enabled native modules to just work
across different versions and flavors of Node.js without recompilation.

A more detailed introduction is provided in:
https://github.com/nodejs/node-eps/blob/master/005-ABI-Stable-Module-API.md
and https://github.com/nodejs/abi-stable-node/blob/doc/VM%20Summit.pdf.

The feature, during its experimental state, will be guarded by a runtime
flag "--napi-modules". Only when this flag is added to the command line
will N-API modules along with regular non N-API modules be supported.

The API is defined by the methods in "src/node_api.h" and
"src/node_api_types.h". This is the best
starting point to review the API surface. More documentation will follow.

In addition to the implementation of the API using V8, which is included
in this PR, the API has also been validated against chakracore and that
port is available in
https://github.com/nodejs/abi-stable-node/tree/api-prototype-chakracore-8.x.

The current plan is to provide N-API support in versions 8.X and 6.X
directly. For older versions, such as 4.X or pre N-API versions of 6.X,
we plan to create an external npm module to provide a migration path
that will allow modules targeting older Node.js versions to use the API,
albeit without getting the advantage of not having to recompile.

In addition, we also plan an external npm package with C++ sugar to
simplify the use of the API. The sugar will be in-line only and will
only use the exported N-API methods but is not part of the N-API
itself. The current version is in:
https://github.com/nodejs/node-api.

This PR is a result of work in the abi-stable-node repo:
https://github.com/nodejs/abi-stable-node/tree/doc,
with this PR being the cumulative work on the api-prototype-8.x
branch with the following contributors in alphabetical order:

Author: Arunesh Chandra <arunesh.chandra@microsoft.com>
Author: Gabriel Schulhof <gabriel.schulhof@intel.com>
Author: Hitesh Kanwathirtha <hiteshk@microsoft.com>
Author: Ian Halliday <ianhall@microsoft.com>
Author: Jason Ginchereau <jasongin@microsoft.com>
Author: Michael Dawson <michael_dawson@ca.ibm.com>
Author: Sampson Gao <sampsong@ca.ibm.com>
Author: Taylor Woll <taylor.woll@microsoft.com>
PR-URL: https://github.com/nodejs/node/pull/11975
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 479 insertions, 0 deletions

diff --git a/src/node_api.h b/src/node_api.h
new file mode 100644
index 00000000000..da14a01654b
--- /dev/null
+++ b/src/node_api.h
@@ -0,0 +1,479 @@
+/******************************************************************************
+ * Experimental prototype for demonstrating VM agnostic and ABI stable API
+ * for native modules to use instead of using Nan and V8 APIs directly.
+ *
+ * The current status is "Experimental" and should not be used for
+ * production applications.  The API is still subject to change
+ * and as an experimental feature is NOT subject to semver.
+ *
+ ******************************************************************************/
+#ifndef SRC_NODE_API_H_
+#define SRC_NODE_API_H_
+
+#include <stddef.h>
+#include <stdbool.h>
+#include "node_api_types.h"
+
+#ifdef _WIN32
+  #ifdef BUILDING_NODE_EXTENSION
+    #ifdef EXTERNAL_NAPI
+      // Building external N-API, or native module against external N-API
+      #define NAPI_EXTERN /* nothing */
+    #else
+      // Building native module against node with built-in N-API
+      #define NAPI_EXTERN __declspec(dllimport)
+    #endif
+  #else
+    // Building node with built-in N-API
+    #define NAPI_EXTERN __declspec(dllexport)
+  #endif
+#else
+  #define NAPI_EXTERN /* nothing */
+#endif
+
+#ifdef _WIN32
+# define NAPI_MODULE_EXPORT __declspec(dllexport)
+#else
+# define NAPI_MODULE_EXPORT __attribute__((visibility("default")))
+#endif
+
+
+typedef void (*napi_addon_register_func)(napi_env env,
+                                         napi_value exports,
+                                         napi_value module,
+                                         void* priv);
+
+typedef struct {
+  int nm_version;
+  unsigned int nm_flags;
+  const char* nm_filename;
+  napi_addon_register_func nm_register_func;
+  const char* nm_modname;
+  void* nm_priv;
+  void* reserved[4];
+} napi_module;
+
+#define NAPI_MODULE_VERSION  1
+
+#if defined(_MSC_VER)
+#pragma section(".CRT$XCU", read)
+#define NAPI_C_CTOR(fn)                                                     \
+  static void __cdecl fn(void);                                             \
+  __declspec(dllexport, allocate(".CRT$XCU")) void(__cdecl * fn##_)(void) = \
+      fn;                                                                   \
+  static void __cdecl fn(void)
+#else
+#define NAPI_C_CTOR(fn)                              \
+  static void fn(void) __attribute__((constructor)); \
+  static void fn(void)
+#endif
+
+#ifdef __cplusplus
+#define EXTERN_C_START extern "C" {
+#define EXTERN_C_END }
+#else
+#define EXTERN_C_START
+#define EXTERN_C_END
+#endif
+
+#define NAPI_MODULE_X(modname, regfunc, priv, flags)                  \
+  EXTERN_C_START                                                      \
+    static napi_module _module =                                      \
+    {                                                                 \
+      NAPI_MODULE_VERSION,                                            \
+      flags,                                                          \
+      __FILE__,                                                       \
+      regfunc,                                                        \
+      #modname,                                                       \
+      priv,                                                           \
+      {0},                                                            \
+    };                                                                \
+    NAPI_C_CTOR(_register_ ## modname) {                              \
+      napi_module_register(&_module);                                 \
+    }                                                                 \
+  EXTERN_C_END
+
+#define NAPI_MODULE(modname, regfunc) \
+  NAPI_MODULE_X(modname, regfunc, NULL, 0)
+
+EXTERN_C_START
+
+NAPI_EXTERN void napi_module_register(napi_module* mod);
+
+NAPI_EXTERN napi_status
+napi_get_last_error_info(napi_env env,
+                         const napi_extended_error_info** result);
+
+// Getters for defined singletons
+NAPI_EXTERN napi_status napi_get_undefined(napi_env env, napi_value* result);
+NAPI_EXTERN napi_status napi_get_null(napi_env env, napi_value* result);
+NAPI_EXTERN napi_status napi_get_global(napi_env env, napi_value* result);
+NAPI_EXTERN napi_status napi_get_boolean(napi_env env,
+                                         bool value,
+                                         napi_value* result);
+
+// Methods to create Primitive types/Objects
+NAPI_EXTERN napi_status napi_create_object(napi_env env, napi_value* result);
+NAPI_EXTERN napi_status napi_create_array(napi_env env, napi_value* result);
+NAPI_EXTERN napi_status napi_create_array_with_length(napi_env env,
+                                                      size_t length,
+                                                      napi_value* result);
+NAPI_EXTERN napi_status napi_create_number(napi_env env,
+                                           double value,
+                                           napi_value* result);
+NAPI_EXTERN napi_status napi_create_string_utf8(napi_env env,
+                                                const char* str,
+                                                size_t length,
+                                                napi_value* result);
+NAPI_EXTERN napi_status napi_create_string_utf16(napi_env env,
+                                                 const char16_t* str,
+                                                 size_t length,
+                                                 napi_value* result);
+NAPI_EXTERN napi_status napi_create_symbol(napi_env env,
+                                           napi_value description,
+                                           napi_value* result);
+NAPI_EXTERN napi_status napi_create_function(napi_env env,
+                                             const char* utf8name,
+                                             napi_callback cb,
+                                             void* data,
+                                             napi_value* result);
+NAPI_EXTERN napi_status napi_create_error(napi_env env,
+                                          napi_value msg,
+                                          napi_value* result);
+NAPI_EXTERN napi_status napi_create_type_error(napi_env env,
+                                               napi_value msg,
+                                               napi_value* result);
+NAPI_EXTERN napi_status napi_create_range_error(napi_env env,
+                                                napi_value msg,
+                                                napi_value* result);
+
+// Methods to get the the native napi_value from Primitive type
+NAPI_EXTERN napi_status napi_typeof(napi_env env,
+                                    napi_value value,
+                                    napi_valuetype* result);
+NAPI_EXTERN napi_status napi_get_value_double(napi_env env,
+                                              napi_value value,
+                                              double* result);
+NAPI_EXTERN napi_status napi_get_value_int32(napi_env env,
+                                             napi_value value,
+                                             int32_t* result);
+NAPI_EXTERN napi_status napi_get_value_uint32(napi_env env,
+                                              napi_value value,
+                                              uint32_t* result);
+NAPI_EXTERN napi_status napi_get_value_int64(napi_env env,
+                                             napi_value value,
+                                             int64_t* result);
+NAPI_EXTERN napi_status napi_get_value_bool(napi_env env,
+                                            napi_value value,
+                                            bool* result);
+
+// Gets the number of CHARACTERS in the string.
+NAPI_EXTERN napi_status napi_get_value_string_length(napi_env env,
+                                                     napi_value value,
+                                                     size_t* result);
+
+// Copies UTF-8 encoded bytes from a string into a buffer.
+NAPI_EXTERN napi_status napi_get_value_string_utf8(napi_env env,
+                                                   napi_value value,
+                                                   char* buf,
+                                                   size_t bufsize,
+                                                   size_t* result);
+
+// Copies UTF-16 encoded bytes from a string into a buffer.
+NAPI_EXTERN napi_status napi_get_value_string_utf16(napi_env env,
+                                                    napi_value value,
+                                                    char16_t* buf,
+                                                    size_t bufsize,
+                                                    size_t* result);
+
+// Methods to coerce values
+// These APIs may execute user scripts
+NAPI_EXTERN napi_status napi_coerce_to_bool(napi_env env,
+                                            napi_value value,
+                                            napi_value* result);
+NAPI_EXTERN napi_status napi_coerce_to_number(napi_env env,
+                                              napi_value value,
+                                              napi_value* result);
+NAPI_EXTERN napi_status napi_coerce_to_object(napi_env env,
+                                              napi_value value,
+                                              napi_value* result);
+NAPI_EXTERN napi_status napi_coerce_to_string(napi_env env,
+                                              napi_value value,
+                                              napi_value* result);
+
+// Methods to work with Objects
+NAPI_EXTERN napi_status napi_get_prototype(napi_env env,
+                                           napi_value object,
+                                           napi_value* result);
+NAPI_EXTERN napi_status napi_get_property_names(napi_env env,
+                                                napi_value object,
+                                                napi_value* result);
+NAPI_EXTERN napi_status napi_set_property(napi_env env,
+                                          napi_value object,
+                                          napi_value key,
+                                          napi_value value);
+NAPI_EXTERN napi_status napi_has_property(napi_env env,
+                                          napi_value object,
+                                          napi_value key,
+                                          bool* result);
+NAPI_EXTERN napi_status napi_get_property(napi_env env,
+                                          napi_value object,
+                                          napi_value key,
+                                          napi_value* result);
+NAPI_EXTERN napi_status napi_set_named_property(napi_env env,
+                                          napi_value object,
+                                          const char* utf8name,
+                                          napi_value value);
+NAPI_EXTERN napi_status napi_has_named_property(napi_env env,
+                                          napi_value object,
+                                          const char* utf8name,
+                                          bool* result);
+NAPI_EXTERN napi_status napi_get_named_property(napi_env env,
+                                          napi_value object,
+                                          const char* utf8name,
+                                          napi_value* result);
+NAPI_EXTERN napi_status napi_set_element(napi_env env,
+                                         napi_value object,
+                                         uint32_t index,
+                                         napi_value value);
+NAPI_EXTERN napi_status napi_has_element(napi_env env,
+                                         napi_value object,
+                                         uint32_t index,
+                                         bool* result);
+NAPI_EXTERN napi_status napi_get_element(napi_env env,
+                                         napi_value object,
+                                         uint32_t index,
+                                         napi_value* result);
+NAPI_EXTERN napi_status
+napi_define_properties(napi_env env,
+                       napi_value object,
+                       size_t property_count,
+                       const napi_property_descriptor* properties);
+
+// Methods to work with Arrays
+NAPI_EXTERN napi_status napi_is_array(napi_env env,
+                                      napi_value value,
+                                      bool* result);
+NAPI_EXTERN napi_status napi_get_array_length(napi_env env,
+                                              napi_value value,
+                                              uint32_t* result);
+
+// Methods to compare values
+NAPI_EXTERN napi_status napi_strict_equals(napi_env env,
+                                           napi_value lhs,
+                                           napi_value rhs,
+                                           bool* result);
+
+// Methods to work with Functions
+NAPI_EXTERN napi_status napi_call_function(napi_env env,
+                                           napi_value recv,
+                                           napi_value func,
+                                           size_t argc,
+                                           const napi_value* argv,
+                                           napi_value* result);
+NAPI_EXTERN napi_status napi_new_instance(napi_env env,
+                                          napi_value constructor,
+                                          size_t argc,
+                                          const napi_value* argv,
+                                          napi_value* result);
+NAPI_EXTERN napi_status napi_instanceof(napi_env env,
+                                        napi_value object,
+                                        napi_value constructor,
+                                        bool* result);
+
+// Napi version of node::MakeCallback(...)
+NAPI_EXTERN napi_status napi_make_callback(napi_env env,
+                                           napi_value recv,
+                                           napi_value func,
+                                           size_t argc,
+                                           const napi_value* argv,
+                                           napi_value* result);
+
+// Methods to work with napi_callbacks
+
+// Gets all callback info in a single call. (Ugly, but faster.)
+NAPI_EXTERN napi_status napi_get_cb_info(
+    napi_env env,               // [in] NAPI environment handle
+    napi_callback_info cbinfo,  // [in] Opaque callback-info handle
+    size_t* argc,      // [in-out] Specifies the size of the provided argv array
+                       // and receives the actual count of args.
+    napi_value* argv,  // [out] Array of values
+    napi_value* thisArg,  // [out] Receives the JS 'this' arg for the call
+    void** data);         // [out] Receives the data pointer for the callback.
+
+NAPI_EXTERN napi_status napi_get_cb_args_length(napi_env env,
+                                                napi_callback_info cbinfo,
+                                                size_t* result);
+NAPI_EXTERN napi_status napi_get_cb_args(napi_env env,
+                                         napi_callback_info cbinfo,
+                                         napi_value* buf,
+                                         size_t bufsize);
+NAPI_EXTERN napi_status napi_get_cb_this(napi_env env,
+                                         napi_callback_info cbinfo,
+                                         napi_value* result);
+
+NAPI_EXTERN napi_status napi_get_cb_data(napi_env env,
+                                         napi_callback_info cbinfo,
+                                         void** result);
+NAPI_EXTERN napi_status napi_is_construct_call(napi_env env,
+                                               napi_callback_info cbinfo,
+                                               bool* result);
+NAPI_EXTERN napi_status napi_set_return_value(napi_env env,
+                                              napi_callback_info cbinfo,
+                                              napi_value value);
+NAPI_EXTERN napi_status
+napi_define_class(napi_env env,
+                  const char* utf8name,
+                  napi_callback constructor,
+                  void* data,
+                  size_t property_count,
+                  const napi_property_descriptor* properties,
+                  napi_value* result);
+
+// Methods to work with external data objects
+NAPI_EXTERN napi_status napi_wrap(napi_env env,
+                                  napi_value js_object,
+                                  void* native_object,
+                                  napi_finalize finalize_cb,
+                                  void* finalize_hint,
+                                  napi_ref* result);
+NAPI_EXTERN napi_status napi_unwrap(napi_env env,
+                                    napi_value js_object,
+                                    void** result);
+NAPI_EXTERN napi_status napi_create_external(napi_env env,
+                                             void* data,
+                                             napi_finalize finalize_cb,
+                                             void* finalize_hint,
+                                             napi_value* result);
+NAPI_EXTERN napi_status napi_get_value_external(napi_env env,
+                                                napi_value value,
+                                                void** result);
+
+// Methods to control object lifespan
+
+// Set initial_refcount to 0 for a weak reference, >0 for a strong reference.
+NAPI_EXTERN napi_status napi_create_reference(napi_env env,
+                                              napi_value value,
+                                              uint32_t initial_refcount,
+                                              napi_ref* result);
+
+// Deletes a reference. The referenced value is released, and may
+// be GC'd unless there are other references to it.
+NAPI_EXTERN napi_status napi_delete_reference(napi_env env, napi_ref ref);
+
+// Increments the reference count, optionally returning the resulting count.
+// After this call the  reference will be a strong reference because its
+// refcount is >0, and the referenced object is effectively "pinned".
+// Calling this when the refcount is 0 and the object is unavailable
+// results in an error.
+NAPI_EXTERN napi_status napi_reference_ref(napi_env env,
+                                           napi_ref ref,
+                                           uint32_t* result);
+
+// Decrements the reference count, optionally returning the resulting count.
+// If the result is 0 the reference is now weak and the object may be GC'd
+// at any time if there are no other references. Calling this when the
+// refcount is already 0 results in an error.
+NAPI_EXTERN napi_status napi_reference_unref(napi_env env,
+                                             napi_ref ref,
+                                             uint32_t* result);
+
+// Attempts to get a referenced value. If the reference is weak,
+// the value might no longer be available, in that case the call
+// is still successful but the result is NULL.
+NAPI_EXTERN napi_status napi_get_reference_value(napi_env env,
+                                                 napi_ref ref,
+                                                 napi_value* result);
+
+NAPI_EXTERN napi_status napi_open_handle_scope(napi_env env,
+                                               napi_handle_scope* result);
+NAPI_EXTERN napi_status napi_close_handle_scope(napi_env env,
+                                                napi_handle_scope scope);
+NAPI_EXTERN napi_status
+napi_open_escapable_handle_scope(napi_env env,
+                                 napi_escapable_handle_scope* result);
+NAPI_EXTERN napi_status
+napi_close_escapable_handle_scope(napi_env env,
+                                  napi_escapable_handle_scope scope);
+
+NAPI_EXTERN napi_status napi_escape_handle(napi_env env,
+                                           napi_escapable_handle_scope scope,
+                                           napi_value escapee,
+                                           napi_value* result);
+
+// Methods to support error handling
+NAPI_EXTERN napi_status napi_throw(napi_env env, napi_value error);
+NAPI_EXTERN napi_status napi_throw_error(napi_env env, const char* msg);
+NAPI_EXTERN napi_status napi_throw_type_error(napi_env env, const char* msg);
+NAPI_EXTERN napi_status napi_throw_range_error(napi_env env, const char* msg);
+NAPI_EXTERN napi_status napi_is_error(napi_env env,
+                                      napi_value value,
+                                      bool* result);
+
+// Methods to support catching exceptions
+NAPI_EXTERN napi_status napi_is_exception_pending(napi_env env, bool* result);
+NAPI_EXTERN napi_status napi_get_and_clear_last_exception(napi_env env,
+                                                          napi_value* result);
+
+// Methods to provide node::Buffer functionality with napi types
+NAPI_EXTERN napi_status napi_create_buffer(napi_env env,
+                                           size_t length,
+                                           void** data,
+                                           napi_value* result);
+NAPI_EXTERN napi_status napi_create_external_buffer(napi_env env,
+                                                    size_t length,
+                                                    void* data,
+                                                    napi_finalize finalize_cb,
+                                                    void* finalize_hint,
+                                                    napi_value* result);
+NAPI_EXTERN napi_status napi_create_buffer_copy(napi_env env,
+                                                size_t length,
+                                                const void* data,
+                                                void** result_data,
+                                                napi_value* result);
+NAPI_EXTERN napi_status napi_is_buffer(napi_env env,
+                                       napi_value value,
+                                       bool* result);
+NAPI_EXTERN napi_status napi_get_buffer_info(napi_env env,
+                                             napi_value value,
+                                             void** data,
+                                             size_t* length);
+
+// Methods to work with array buffers and typed arrays
+NAPI_EXTERN napi_status napi_is_arraybuffer(napi_env env,
+                                            napi_value value,
+                                            bool* result);
+NAPI_EXTERN napi_status napi_create_arraybuffer(napi_env env,
+                                                size_t byte_length,
+                                                void** data,
+                                                napi_value* result);
+NAPI_EXTERN napi_status
+napi_create_external_arraybuffer(napi_env env,
+                                 void* external_data,
+                                 size_t byte_length,
+                                 napi_finalize finalize_cb,
+                                 void* finalize_hint,
+                                 napi_value* result);
+NAPI_EXTERN napi_status napi_get_arraybuffer_info(napi_env env,
+                                                  napi_value arraybuffer,
+                                                  void** data,
+                                                  size_t* byte_length);
+NAPI_EXTERN napi_status napi_is_typedarray(napi_env env,
+                                           napi_value value,
+                                           bool* result);
+NAPI_EXTERN napi_status napi_create_typedarray(napi_env env,
+                                               napi_typedarray_type type,
+                                               size_t length,
+                                               napi_value arraybuffer,
+                                               size_t byte_offset,
+                                               napi_value* result);
+NAPI_EXTERN napi_status napi_get_typedarray_info(napi_env env,
+                                                 napi_value typedarray,
+                                                 napi_typedarray_type* type,
+                                                 size_t* length,
+                                                 void** data,
+                                                 napi_value* arraybuffer,
+                                                 size_t* byte_offset);
+EXTERN_C_END
+
+#endif  // SRC_NODE_API_H__