add `Key()` method to the `Handler` concept

For more details see: https://github.com/miloyip/rapidjson/issues/132

This commit tries to minimize the required code changes and forwards the `Handler::Key()` calls to `Handler::String()` wherever possible in order to not break existing code; or at least not code deriving from `BaseReaderHandler` when implementing a custom `Handler`.

2 files changed, 34 insertions, 10 deletions

diff --git a/include/rapidjson/document.h b/include/rapidjson/document.h
index 13acb381..310fc710 100644
--- a/include/rapidjson/document.h
+++ b/include/rapidjson/document.h
@@ -1386,7 +1386,7 @@ int z = a[0u].GetInt();             // This works too.
             if (!handler.StartObject())

                 return false;

             for (ConstMemberIterator m = MemberBegin(); m != MemberEnd(); ++m) {

-                if (!handler.String(m->name.GetString(), m->name.GetStringLength(), (m->name.flags_ & kCopyFlag) != 0))

+                if (!handler.Key(m->name.GetString(), m->name.GetStringLength(), (m->name.flags_ & kCopyFlag) != 0))

                     return false;

                 if (!m->value.Accept(handler))

                     return false;

@@ -1794,6 +1794,8 @@ private:
 

     bool StartObject() { new (stack_.template Push<ValueType>()) ValueType(kObjectType); return true; }

     

+    bool Key(const Ch* str, SizeType length, bool copy) { return String(str, length, copy); }

+

     bool EndObject(SizeType memberCount) {

         typename ValueType::Member* members = stack_.template Pop<typename ValueType::Member>(memberCount);

         stack_.template Top<ValueType>()->SetObjectRaw(members, (SizeType)memberCount, GetAllocator());

diff --git a/include/rapidjson/reader.h b/include/rapidjson/reader.h
index 701255fa..f02dd161 100644
--- a/include/rapidjson/reader.h
+++ b/include/rapidjson/reader.h
@@ -152,6 +152,7 @@ concept Handler {
     bool Double(double d);

     bool String(const Ch* str, SizeType length, bool copy);

     bool StartObject();

+    bool Key(const Ch* str, SizeType length, bool copy);

     bool EndObject(SizeType memberCount);

     bool StartArray();

     bool EndArray(SizeType elementCount);

@@ -181,6 +182,7 @@ struct BaseReaderHandler {
     bool Double(double) { return static_cast<Override&>(*this).Default(); }

     bool String(const Ch*, SizeType, bool) { return static_cast<Override&>(*this).Default(); }

     bool StartObject() { return static_cast<Override&>(*this).Default(); }

+    bool Key(const Ch* str, SizeType len, bool copy) { return String(str, len, copy); }

     bool EndObject(SizeType) { return static_cast<Override&>(*this).Default(); }

     bool StartArray() { return static_cast<Override&>(*this).Default(); }

     bool EndArray(SizeType) { return static_cast<Override&>(*this).Default(); }

@@ -471,7 +473,7 @@ private:
             if (is.Peek() != '"')

                 RAPIDJSON_PARSE_ERROR(kParseErrorObjectMissName, is.Tell());

 

-            ParseString<parseFlags>(is, handler);

+            ParseKey<parseFlags>(is, handler);

             RAPIDJSON_PARSE_ERROR_EARLY_RETURN_VOID;

 

             SkipWhitespace(is);

@@ -576,7 +578,7 @@ private:
             RAPIDJSON_PARSE_ERROR(kParseErrorValueInvalid, is.Tell() - 1);

     }

 

-    // Helper function to parse four hexidecimal digits in \uXXXX in ParseString().

+    // Helper function to parse four hexidecimal digits in \uXXXX in ParseStringOrKey().

     template<typename InputStream>

     unsigned ParseHex4(InputStream& is) {

         unsigned codepoint = 0;

@@ -616,8 +618,8 @@ private:
     };

 

     // Parse string and generate String event. Different code paths for kParseInsituFlag.

-    template<unsigned parseFlags, typename InputStream, typename Handler>

-    void ParseString(InputStream& is, Handler& handler) {

+    template<unsigned parseFlags, bool isKey, typename InputStream, typename Handler>

+    void ParseStringOrKey(InputStream& is, Handler& handler) {

         internal::StreamLocalCopy<InputStream> copy(is);

         InputStream& s(copy.s);

 

@@ -627,18 +629,38 @@ private:
             RAPIDJSON_PARSE_ERROR_EARLY_RETURN_VOID;

             size_t length = s.PutEnd(head) - 1;

             RAPIDJSON_ASSERT(length <= 0xFFFFFFFF);

-            if (!handler.String((typename TargetEncoding::Ch*)head, SizeType(length), false))

-                RAPIDJSON_PARSE_ERROR(kParseErrorTermination, s.Tell());

+            if (isKey) {

+                if (!handler.Key((typename TargetEncoding::Ch*)head, SizeType(length), false))

+                    RAPIDJSON_PARSE_ERROR(kParseErrorTermination, s.Tell());

+            } else {

+                if (!handler.String((typename TargetEncoding::Ch*)head, SizeType(length), false))

+                    RAPIDJSON_PARSE_ERROR(kParseErrorTermination, s.Tell());

+            }

         }

         else {

             StackStream stackStream(stack_);

             ParseStringToStream<parseFlags, SourceEncoding, TargetEncoding>(s, stackStream);

             RAPIDJSON_PARSE_ERROR_EARLY_RETURN_VOID;

-            if (!handler.String(stack_.template Pop<typename TargetEncoding::Ch>(stackStream.length_), stackStream.length_ - 1, true))

-                RAPIDJSON_PARSE_ERROR(kParseErrorTermination, s.Tell());

+            if (isKey) {

+                if (!handler.Key(stack_.template Pop<typename TargetEncoding::Ch>(stackStream.length_), stackStream.length_ - 1, true))

+                    RAPIDJSON_PARSE_ERROR(kParseErrorTermination, s.Tell());

+            } else {

+                if (!handler.String(stack_.template Pop<typename TargetEncoding::Ch>(stackStream.length_), stackStream.length_ - 1, true))

+                    RAPIDJSON_PARSE_ERROR(kParseErrorTermination, s.Tell());

+            }

         }

     }

 

+    template<unsigned parseFlags, typename InputStream, typename Handler>

+    void ParseKey(InputStream& is, Handler& handler) {

+        return ParseStringOrKey<parseFlags, true>(is, handler);

+    }

+

+    template<unsigned parseFlags, typename InputStream, typename Handler>

+    void ParseString(InputStream& is, Handler& handler) {

+        return ParseStringOrKey<parseFlags, false>(is, handler);

+    }

+

     // Parse string to an output is

     // This function handles the prefix/suffix double quotes, escaping, and optional encoding validation.

     template<unsigned parseFlags, typename SEncoding, typename TEncoding, typename InputStream, typename OutputStream>

@@ -1194,7 +1216,7 @@ private:
         }

 

         case IterativeParsingMemberKeyState:

-            ParseString<parseFlags>(is, handler);

+            ParseKey<parseFlags>(is, handler);

             if (HasParseError())

                 return IterativeParsingErrorState;

             else