GenerateText generate a text string for default identifier of enum and float…

GenerateText generate a text string for default identifier of enum and float scalar. An enum identifier printed as the strictly quoted string. (#4527)

src/idl_gen_text.cpp

@@ -53,7 +53,9 @@ bool Print(T val, Type type, int /*indent*/, Type * /*union_type*/,
   if (type.enum_def && opts.output_enum_identifiers) {
     auto enum_val = type.enum_def->ReverseLookup(static_cast<int>(val));
     if (enum_val) {
-      OutputIdentifier(enum_val->name, opts, _text);
+      text += "\"";
+      text += enum_val->name;
+      text += "\"";
       return true;
     }
   }
@@ -147,12 +149,17 @@ bool Print<const void *>(const void *val, Type type, int indent,
 }
 
 // Generate text for a scalar field.
-template<typename T>
-static bool GenField(const FieldDef &fd, const Table *table, bool fixed,
-                     const IDLOptions &opts, int indent, std::string *_text) {
-  return Print(fixed ? reinterpret_cast<const Struct *>(table)->GetField<T>(
-                           fd.value.offset)
-                     : table->GetField<T>(fd.value.offset, 0),
+template<typename T> static bool GenField(const FieldDef &fd,
+                                          const Table *table, bool fixed,
+                                          const IDLOptions &opts,
+                                          int indent,
+                                          std::string *_text) {
+  return Print(fixed ?
+    reinterpret_cast<const Struct *>(table)->GetField<T>(fd.value.offset) :
+    table->GetField<T>(fd.value.offset,
+    IsFloat(fd.value.type.base_type) ?
+    static_cast<T>(strtod(fd.value.constant.c_str(), nullptr)) :
+    static_cast<T>(StringToInt(fd.value.constant.c_str()))),
     fd.value.type, indent, nullptr, opts, _text);
 }
 
@@ -212,7 +219,6 @@ static bool GenStruct(const StructDef &struct_def, const Table *table,
            fd.value.type.base_type != BASE_TYPE_VECTOR))
         text += ":";
       text += " ";
-      if (is_present) {
       switch (fd.value.type.base_type) {
           // clang-format off
           #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
@@ -241,11 +247,7 @@ static bool GenStruct(const StructDef &struct_def, const Table *table,
       if (fd.value.type.base_type == BASE_TYPE_UTYPE) {
         auto enum_val = fd.value.type.enum_def->ReverseLookup(
             table->GetField<uint8_t>(fd.value.offset, 0));
-          assert(enum_val);
-          union_type = &enum_val->union_type;
-        }
-      } else {
-        text += fd.value.constant;
+        union_type = enum_val ? &enum_val->union_type : nullptr;
       }
     }
   }

tests/monsterdata_test.golden

@@ -4,7 +4,7 @@
     y: 2.0,
     z: 3.0,
     test1: 3.0,
-    test2: Green,
+    test2: "Green",
     test3: {
       a: 10,
       b: 20
@@ -24,7 +24,7 @@
     8,
     9
   ],
-  test_type: Monster,
+  test_type: "Monster",
   test: {
     name: "Fred"
   },

tests/test.cpp

@@ -541,6 +541,37 @@ void TriviallyCopyableTest() {
   // clang-format on
 }
 
+// Check stringify of an default enum value to json
+void JsonDefaultTest() {
+  // load FlatBuffer schema (.fbs) from disk
+  std::string schemafile;
+  TEST_EQ(flatbuffers::LoadFile((test_data_path + "monster_test.fbs").c_str(),
+                                false, &schemafile), true);
+  // parse schema first, so we can use it to parse the data after
+  flatbuffers::Parser parser;
+  auto include_test_path =
+      flatbuffers::ConCatPathFileName(test_data_path, "include_test");
+  const char *include_directories[] = { test_data_path.c_str(),
+                                        include_test_path.c_str(), nullptr };
+
+  TEST_EQ(parser.Parse(schemafile.c_str(), include_directories), true);
+  // create incomplete monster and store to json
+  parser.opts.output_default_scalars_in_json = true;
+  parser.opts.output_enum_identifiers = true;
+  flatbuffers::FlatBufferBuilder builder;
+  auto name = builder.CreateString("default_enum");
+  MonsterBuilder color_monster(builder);
+  color_monster.add_name(name);
+  FinishMonsterBuffer(builder, color_monster.Finish());
+  std::string jsongen;
+  auto result = GenerateText(parser, builder.GetBufferPointer(), &jsongen);
+  TEST_EQ(result, true);
+  // default value of the "color" field is Blue
+  TEST_EQ(std::string::npos != jsongen.find("color: \"Blue\""), true);
+  // default value of the "testf" field is 3.14159
+  TEST_EQ(std::string::npos != jsongen.find("testf: 3.14159"), true);
+}
+
 // example of parsing text straight into a buffer, and generating
 // text back from it:
 void ParseAndGenerateTextTest() {
@@ -1936,6 +1967,8 @@ int main(int /*argc*/, const char * /*argv*/ []) {
   TypeAliasesTest();
   EndianSwapTest();
 
+  JsonDefaultTest();
+  
   FlexBuffersTest();
 
   if (!testing_fails) {