Added support for mini-reflection tables.

Change-Id: I83453d074685fa57bbf1c7c87b1d9392ce972085
Tested: on Linux.

CMakeLists.txt

@@ -34,6 +34,7 @@ set(FlatBuffers_Library_SRCS
   include/flatbuffers/stl_emulation.h
   include/flatbuffers/flexbuffers.h
   include/flatbuffers/registry.h
+  include/flatbuffers/minireflect.h
   src/code_generators.cpp
   src/idl_parser.cpp
   src/idl_gen_text.cpp
@@ -200,6 +201,7 @@ function(compile_flatbuffers_schema_to_cpp SRC_FBS)
     COMMAND "${FLATBUFFERS_FLATC_EXECUTABLE}" -c --no-includes --gen-mutable
             --gen-object-api -o "${SRC_FBS_DIR}"
             --cpp-ptr-type flatbuffers::unique_ptr # Used to test with C++98 STLs
+            --reflect-names
             -I "${CMAKE_CURRENT_SOURCE_DIR}/tests/include_test"
             "${CMAKE_CURRENT_SOURCE_DIR}/${SRC_FBS}"
     DEPENDS flatc)

docs/source/Compiler.md

@@ -125,5 +125,8 @@ Additional options:
 
 -   `--keep-prefix` : Keep original prefix of schema include statement.
 
+-   `--reflect-types` : Add minimal type reflection to code generation.
+-   `--reflect-names` : Add minimal type/name reflection.
+
 NOTE: short-form options for generators are deprecated, use the long form
 whenever possible.

docs/source/CppUsage.md

@@ -231,6 +231,30 @@ schema, as well as a lot of helper functions.
 And example of usage, for the time being, can be found in
 `test.cpp/ReflectionTest()`.
 
+## Mini Reflection
+
+A more limited form of reflection is available for direct inclusion in
+generated code, which doesn't any (binary) schema access at all. It was designed
+to keep the overhead of reflection as low as possible (on the order of 2-6
+bytes per field added to your executable), but doesn't contain all the
+information the (binary) schema contains.
+
+You add this information to your generated code by specifying `--reflect-types`
+(or instead `--reflect-names` if you also want field / enum names).
+
+You can now use this information, for example to print a FlatBuffer to text:
+
+    auto s = flatbuffers::FlatBufferToString(flatbuf, MonsterTypeTable());
+
+`MonsterTypeTable()` is declared in the generated code for each type. The
+string produced is very similar to the JSON produced by the `Parser` based
+text generator.
+
+You'll need `flatbuffers/minireflect.h` for this functionality. In there is also
+a convenient visitor/iterator so you can write your own output / functionality
+based on the mini reflection tables without having to know the FlatBuffers or
+reflection encoding.
+
 ## Storing maps / dictionaries in a FlatBuffer
 
 FlatBuffers doesn't support maps natively, but there is support to

include/flatbuffers/flatbuffers.h

@@ -2066,6 +2066,73 @@ inline int LookupEnum(const char **names, const char *name) {
   #error Unknown compiler, please define structure alignment macros
 #endif
 
+// Minimal reflection via code generation.
+// Besides full-fat reflection (see reflection.h) and parsing/printing by
+// loading schemas (see idl.h), we can also have code generation for mimimal
+// reflection data which allows pretty-printing and other uses without needing
+// a schema or a parser.
+// Generate code with --reflect-types (types only) or --reflect-names (names
+// also) to enable.
+// See minireflect.h for utilities using this functionality.
+
+// These types are organized slightly differently as the ones in idl.h.
+enum SequenceType { ST_TABLE, ST_STRUCT, ST_UNION, ST_ENUM };
+
+// Scalars have the same order as in idl.h
+#define FLATBUFFERS_GEN_ELEMENTARY_TYPES(ET) \
+  ET(ET_UTYPE) \
+  ET(ET_BOOL) \
+  ET(ET_CHAR) \
+  ET(ET_UCHAR) \
+  ET(ET_SHORT) \
+  ET(ET_USHORT) \
+  ET(ET_INT) \
+  ET(ET_UINT) \
+  ET(ET_LONG) \
+  ET(ET_ULONG) \
+  ET(ET_FLOAT) \
+  ET(ET_DOUBLE) \
+  ET(ET_STRING) \
+  ET(ET_SEQUENCE)  // See SequenceType.
+
+enum ElementaryType {
+  #define FLATBUFFERS_ET(E) E,
+    FLATBUFFERS_GEN_ELEMENTARY_TYPES(FLATBUFFERS_ET)
+  #undef FLATBUFFERS_ET
+};
+
+inline const char **ElementaryTypeNames() {
+  static const char *names[] = {
+    #define FLATBUFFERS_ET(E) #E,
+      FLATBUFFERS_GEN_ELEMENTARY_TYPES(FLATBUFFERS_ET)
+    #undef FLATBUFFERS_ET
+  };
+  return names;
+}
+
+// Basic type info cost just 16bits per field!
+struct TypeCode {
+  uint16_t base_type : 4;      // ElementaryType
+  uint16_t is_vector : 1;
+  int16_t sequence_ref : 11;   // Index into type_refs below, or -1 for none.
+};
+
+static_assert(sizeof(TypeCode) == 2, "TypeCode");
+
+struct TypeTable;
+
+// Signature of the static method present in each type.
+typedef TypeTable *(*TypeFunction)();
+
+struct TypeTable {
+  SequenceType st;
+  size_t num_elems;  // of each of the arrays below.
+  const TypeCode *type_codes;
+  const TypeFunction *type_refs;
+  const int32_t *values;  // Only set for non-consecutive enum/union or structs.
+  const char **names;  // Only set if compiled with --reflect-names.
+};
+
 // String which identifies the current version of FlatBuffers.
 // flatbuffer_version_string is used by Google developers to identify which
 // applications uploaded to Google Play are using this library.  This allows

include/flatbuffers/idl.h

@@ -396,6 +396,10 @@ struct IDLOptions {
 
   Language lang;
 
+  enum MiniReflect { kNone, kTypes, kTypesAndNames };
+
+  MiniReflect mini_reflect;
+
   // The corresponding language bit will be set if a language is included
   // for code generation.
   unsigned long lang_to_generate;
@@ -426,6 +430,7 @@ struct IDLOptions {
       reexport_ts_modules(true),
       protobuf_ascii_alike(false),
       lang(IDLOptions::kJava),
+      mini_reflect(IDLOptions::kNone),
       lang_to_generate(0) {}
 };
 

include/flatbuffers/minireflect.h

+/*
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FLATBUFFERS_MINIREFLECT_H_
+#define FLATBUFFERS_MINIREFLECT_H_
+
+#include "flatbuffers/flatbuffers.h"
+#include "flatbuffers/util.h"
+
+namespace flatbuffers {
+
+// Utilities that can be used with the "mini reflection" tables present
+// in generated code with --reflect-types (only types) or --reflect-names
+// (also names).
+// This allows basic reflection functionality such as pretty-printing
+// that does not require the use of the schema parser or loading of binary
+// schema files at runtime (reflection.h).
+
+// For any of the functions below that take `const TypeTable *`, you pass
+// `FooTypeTable()` if the type of the root is `Foo`.
+
+// First, a generic iterator that can be used by multiple algorithms.
+
+struct IterationVisitor {
+  // These mark the scope of a table or struct.
+  virtual void StartSequence() {}
+  virtual void EndSequence() {}
+  // Called for each field regardless of wether it is present or not.
+  // If not present, val == nullptr. set_idx is the index of all set fields.
+  virtual void Field(size_t /*field_idx*/, size_t /*set_idx*/,
+                     ElementaryType /*type*/, bool /*is_vector*/,
+                     const TypeTable * /*type_table*/, const char * /*name*/,
+                     const uint8_t * /*val*/) {}
+  // Called for a value that is actually present, after a field, or as part
+  // of a vector.
+  virtual void UType(uint8_t, const char *) {}
+  virtual void Bool(bool) {}
+  virtual void Char(int8_t, const char *) {}
+  virtual void UChar(uint8_t, const char *) {}
+  virtual void Short(int16_t, const char *) {}
+  virtual void UShort(uint16_t, const char *) {}
+  virtual void Int(int32_t, const char *) {}
+  virtual void UInt(uint32_t, const char *) {}
+  virtual void Long(int64_t) {}
+  virtual void ULong(uint64_t) {}
+  virtual void Float(float) {}
+  virtual void Double(double) {}
+  virtual void String(const String *) {}
+  virtual void Unknown(const uint8_t *) {}  // From a future version.
+  // These mark the scope of a vector.
+  virtual void StartVector() {}
+  virtual void EndVector() {}
+  virtual void Element(size_t /*i*/, ElementaryType /*type*/,
+                       const TypeTable * /*type_table*/,
+                       const uint8_t * /*val*/)
+  {}
+  virtual ~IterationVisitor() {}
+};
+
+inline size_t InlineSize(ElementaryType type, const TypeTable *type_table) {
+  switch (type) {
+    case ET_UTYPE:
+    case ET_BOOL:
+    case ET_CHAR:
+    case ET_UCHAR:
+      return 1;
+    case ET_SHORT:
+    case ET_USHORT:
+      return 2;
+    case ET_INT:
+    case ET_UINT:
+    case ET_FLOAT:
+    case ET_STRING:
+      return 4;
+    case ET_LONG:
+    case ET_ULONG:
+    case ET_DOUBLE:
+      return 8;
+    case ET_SEQUENCE:
+      switch (type_table->st) {
+        case ST_TABLE:
+        case ST_UNION:
+          return 4;
+        case ST_STRUCT:
+          return type_table->values[type_table->num_elems];
+        default:
+          assert(false);
+          return 1;
+      }
+    default:
+      assert(false);
+      return 1;
+  }
+}
+
+inline int32_t LookupEnum(int32_t enum_val, const int32_t *values,
+                          size_t num_values) {
+  if (!values) return enum_val;
+  for (size_t i = 0; i < num_values; i++) {
+    if (enum_val == values[i]) return static_cast<int32_t>(i);
+  }
+  return -1;  // Unknown enum value.
+}
+
+template<typename T> const char *EnumName(T tval, const TypeTable *type_table) {
+  if (!type_table || !type_table->names) return nullptr;
+  auto i = LookupEnum(static_cast<int32_t>(tval), type_table->values,
+                                  type_table->num_elems);
+  if (i >= 0 && i < static_cast<int32_t>(type_table->num_elems)) {
+    return type_table->names[i];
+  }
+  return nullptr;
+}
+
+void IterateObject(const uint8_t *obj, const TypeTable *type_table,
+                  IterationVisitor *visitor);
+
+inline void IterateValue(ElementaryType type, const uint8_t *val,
+                         const TypeTable *type_table,
+                         const uint8_t *prev_val,
+                         soffset_t vector_index,
+                         IterationVisitor *visitor) {
+  switch (type) {
+    case ET_UTYPE: {
+      auto tval = *reinterpret_cast<const uint8_t *>(val);
+      visitor->UType(tval, EnumName(tval, type_table));
+      break;
+    }
+    case ET_BOOL: {
+      visitor->Bool(*reinterpret_cast<const uint8_t *>(val) != 0);
+      break;
+    }
+    case ET_CHAR: {
+      auto tval = *reinterpret_cast<const int8_t *>(val);
+      visitor->Char(tval, EnumName(tval, type_table));
+      break;
+    }
+    case ET_UCHAR: {
+      auto tval = *reinterpret_cast<const uint8_t *>(val);
+      visitor->UChar(tval, EnumName(tval, type_table));
+      break;
+    }
+    case ET_SHORT: {
+      auto tval = *reinterpret_cast<const int16_t *>(val);
+      visitor->Short(tval, EnumName(tval, type_table));
+      break;
+    }
+    case ET_USHORT: {
+      auto tval = *reinterpret_cast<const uint16_t *>(val);
+      visitor->UShort(tval, EnumName(tval, type_table));
+      break;
+    }
+    case ET_INT: {
+      auto tval = *reinterpret_cast<const int32_t *>(val);
+      visitor->Int(tval, EnumName(tval, type_table));
+      break;
+    }
+    case ET_UINT: {
+      auto tval = *reinterpret_cast<const uint32_t *>(val);
+      visitor->UInt(tval, EnumName(tval, type_table));
+      break;
+    }
+    case ET_LONG: {
+      visitor->Long(*reinterpret_cast<const int64_t *>(val));
+      break;
+    }
+    case ET_ULONG: {
+      visitor->ULong(*reinterpret_cast<const uint64_t *>(val));
+      break;
+    }
+    case ET_FLOAT: {
+      visitor->Float(*reinterpret_cast<const float *>(val));
+      break;
+    }
+    case ET_DOUBLE: {
+      visitor->Double(*reinterpret_cast<const double *>(val));
+      break;
+    }
+    case ET_STRING: {
+      val += ReadScalar<uoffset_t>(val);
+      visitor->String(reinterpret_cast<const String *>(val));
+      break;
+    }
+    case ET_SEQUENCE: {
+      switch (type_table->st) {
+        case ST_TABLE:
+          val += ReadScalar<uoffset_t>(val);
+          IterateObject(val, type_table, visitor);
+          break;
+        case ST_STRUCT:
+          IterateObject(val, type_table, visitor);
+          break;
+        case ST_UNION: {
+          val += ReadScalar<uoffset_t>(val);
+          assert(prev_val);
+          auto union_type = *prev_val;  // Always a uint8_t.
+          if (vector_index >= 0) {
+            auto type_vec = reinterpret_cast<const Vector<uint8_t> *>(prev_val);
+            union_type = type_vec->Get(static_cast<uoffset_t>(vector_index));
+          }
+          auto type_code_idx = LookupEnum(union_type, type_table->values,
+                                          type_table->num_elems);
+          if (type_code_idx >= 0 && type_code_idx <
+              static_cast<int32_t>(type_table->num_elems)) {
+            auto type_code = type_table->type_codes[type_code_idx];
+            switch (type_code.base_type) {
+              case ET_SEQUENCE: {
+                auto ref = type_table->type_refs[type_code.sequence_ref]();
+                IterateObject(val, ref, visitor);
+                break;
+              }
+              case ET_STRING:
+                visitor->String(reinterpret_cast<const String *>(val));
+                break;
+              default:
+                visitor->Unknown(val);
+            }
+          } else {
+            visitor->Unknown(val);
+          }
+          break;
+        }
+        case ST_ENUM:
+          assert(false);
+          break;
+      }
+      break;
+    }
+    default: {
+      visitor->Unknown(val);
+      break;
+    }
+  }
+}
+
+inline void IterateObject(const uint8_t *obj, const TypeTable *type_table,
+                          IterationVisitor *visitor) {
+  visitor->StartSequence();
+  const uint8_t *prev_val = nullptr;
+  size_t set_idx = 0;
+  for (size_t i = 0; i < type_table->num_elems; i++) {
+    auto type_code = type_table->type_codes[i];
+    auto type = static_cast<ElementaryType>(type_code.base_type);
+    auto is_vector = type_code.is_vector != 0;
+    auto ref_idx = type_code.sequence_ref;
+    const TypeTable *ref = nullptr;
+    if (ref_idx >= 0) {
+      ref = type_table->type_refs[ref_idx]();
+    }
+    auto name = type_table->names ? type_table->names[i] : nullptr;
+    const uint8_t *val = nullptr;
+    if (type_table->st == ST_TABLE) {
+      val = reinterpret_cast<const Table *>(obj)->GetAddressOf(
+              FieldIndexToOffset(static_cast<voffset_t>(i)));
+    } else {
+      val = obj + type_table->values[i];
+    }
+    visitor->Field(i, set_idx, type, is_vector, ref, name, val);
+    if (val) {
+      set_idx++;
+      if (is_vector) {
+        val += ReadScalar<uoffset_t>(val);
+        auto vec = reinterpret_cast<const Vector<uint8_t> *>(val);
+        visitor->StartVector();
+        auto elem_ptr = vec->Data();
+        for (size_t j = 0; j < vec->size(); j++) {
+          visitor->Element(j, type, ref, elem_ptr);
+          IterateValue(type, elem_ptr, ref, prev_val, static_cast<soffset_t>(j),
+                       visitor);
+          elem_ptr += InlineSize(type, ref);
+        }
+        visitor->EndVector();
+      } else {
+        IterateValue(type, val, ref, prev_val, -1, visitor);
+      }
+    }
+    prev_val = val;
+  }
+  visitor->EndSequence();
+}
+
+inline void IterateFlatBuffer(const uint8_t *buffer,
+                              const TypeTable *type_table,
+                              IterationVisitor *callback) {
+  IterateObject(GetRoot<uint8_t>(buffer), type_table, callback);
+}
+
+// Outputting a Flatbuffer to a string. Tries to conform as close to JSON /
+// the output generated by idl_gen_text.cpp.
+
+struct ToStringVisitor : public IterationVisitor {
+  std::string s;
+  void StartSequence() { s += "{ "; }
+  void EndSequence() { s += " }"; }
+  void Field(size_t /*field_idx*/, size_t set_idx, ElementaryType /*type*/,
+             bool /*is_vector*/, const TypeTable * /*type_table*/,
+             const char *name, const uint8_t *val) {
+    if (!val) return;
+    if (set_idx) s += ", ";
+    if (name) { s += name; s += ": "; }
+  }
+  template<typename T> void Named(T x, const char *name) {
+    if (name) s+= name;
+    else s+= NumToString(x);
+  }
+  void UType(uint8_t x, const char *name) { Named(x, name); }
+  void Bool(bool x) { s+= x ? "true" : "false"; }
+  void Char(int8_t x, const char *name) { Named(x, name); }
+  void UChar(uint8_t x, const char *name) { Named(x, name); }
+  void Short(int16_t x, const char *name) { Named(x, name); }
+  void UShort(uint16_t x, const char *name) { Named(x, name); }
+  void Int(int32_t x, const char *name) { Named(x, name); }
+  void UInt(uint32_t x, const char *name) { Named(x, name); }
+  void Long(int64_t x) { s+= NumToString(x); }
+  void ULong(uint64_t x) { s+= NumToString(x); }
+  void Float(float x) { s+= NumToString(x); }
+  void Double(double x) { s+= NumToString(x); }
+  void String(const struct String *str) {
+    EscapeString(str->c_str(), str->size(), &s, true);
+  }
+  void Unknown(const uint8_t *) { s += "(?)"; }
+  void StartVector() { s += "[ "; }
+  void EndVector() { s += " ]"; }
+  void Element(size_t i, ElementaryType /*type*/,
+               const TypeTable * /*type_table*/, const uint8_t * /*val*/) {
+    if (i) s += ", ";
+  }
+};
+
+inline std::string FlatBufferToString(const uint8_t *buffer,
+                                      const TypeTable *type_table) {
+  ToStringVisitor tostring_visitor;
+  IterateFlatBuffer(buffer, type_table, &tostring_visitor);
+  return tostring_visitor.s;
+}
+
+}  // namespace flatbuffers
+
+#endif  // FLATBUFFERS_MINIREFLECT_H_

samples/monster_generated.h

@@ -605,6 +605,120 @@ inline void EquipmentUnion::Reset() {
   type = Equipment_NONE;
 }
 
+flatbuffers::TypeTable *Vec3TypeTable();
+
+flatbuffers::TypeTable *MonsterTypeTable();
+
+flatbuffers::TypeTable *WeaponTypeTable();
+
+flatbuffers::TypeTable *ColorTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_CHAR, 0, 0 },
+    { flatbuffers::ET_CHAR, 0, 0 },
+    { flatbuffers::ET_CHAR, 0, 0 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    ColorTypeTable
+  };
+  static const char *names[] = {
+    "Red",
+    "Green",
+    "Blue"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_ENUM, 3, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *EquipmentTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_SEQUENCE, 0, -1 },
+    { flatbuffers::ET_SEQUENCE, 0, 0 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    WeaponTypeTable
+  };
+  static const char *names[] = {
+    "NONE",
+    "Weapon"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_UNION, 2, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *Vec3TypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_FLOAT, 0, -1 },
+    { flatbuffers::ET_FLOAT, 0, -1 },
+    { flatbuffers::ET_FLOAT, 0, -1 }
+  };
+  static const int32_t values[] = { 0, 4, 8, 12 };
+  static const char *names[] = {
+    "x",
+    "y",
+    "z"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_STRUCT, 3, type_codes, nullptr, values, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *MonsterTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_SEQUENCE, 0, 0 },
+    { flatbuffers::ET_SHORT, 0, -1 },
+    { flatbuffers::ET_SHORT, 0, -1 },
+    { flatbuffers::ET_STRING, 0, -1 },
+    { flatbuffers::ET_BOOL, 0, -1 },
+    { flatbuffers::ET_UCHAR, 1, -1 },
+    { flatbuffers::ET_CHAR, 0, 1 },
+    { flatbuffers::ET_SEQUENCE, 1, 2 },
+    { flatbuffers::ET_UTYPE, 0, 3 },
+    { flatbuffers::ET_SEQUENCE, 0, 3 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    Vec3TypeTable,
+    ColorTypeTable,
+    WeaponTypeTable,
+    EquipmentTypeTable
+  };
+  static const char *names[] = {
+    "pos",
+    "mana",
+    "hp",
+    "name",
+    "friendly",
+    "inventory",
+    "color",
+    "weapons",
+    "equipped_type",
+    "equipped"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 10, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *WeaponTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_STRING, 0, -1 },
+    { flatbuffers::ET_SHORT, 0, -1 }
+  };
+  static const char *names[] = {
+    "name",
+    "damage"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 2, type_codes, nullptr, nullptr, names
+  };
+  return &tt;
+}
+
 inline const MyGame::Sample::Monster *GetMonster(const void *buf) {
   return flatbuffers::GetRoot<MyGame::Sample::Monster>(buf);
 }

src/flatc.cpp

@@ -111,6 +111,8 @@ std::string FlatCompiler::GetUsageString(const char* program_name) const {
       "  --keep-prefix      Keep original prefix of schema include statement.\n"
       "  --no-fb-import     Don't include flatbuffers import statement for TypeScript.\n"
       "  --no-ts-reexport   Don't re-export imported dependencies for TypeScript.\n"
+      "  --reflect-types    Add minimal type reflection to code generation.\n"
+      "  --reflect-names    Add minimal type/name reflection.\n"
       "FILEs may be schemas (must end in .fbs), or JSON files (conforming to preceding\n"
       "schema). FILEs after the -- must be binary flatbuffer format files.\n"
       "Output files are named using the base file name of the input,\n"
@@ -243,6 +245,10 @@ int FlatCompiler::Compile(int argc, const char** argv) {
         opts.skip_flatbuffers_import = true;
       } else if(arg == "--no-ts-reexport") {
         opts.reexport_ts_modules = false;
+      } else if(arg == "--reflect-types") {
+        opts.mini_reflect = IDLOptions::kTypes;
+      } else if(arg == "--reflect-names") {
+        opts.mini_reflect = IDLOptions::kTypesAndNames;
       } else {
         for (size_t i = 0; i < params_.num_generators; ++i) {
           if (arg == params_.generators[i].generator_opt_long ||

src/idl_gen_cpp.cpp

@@ -169,6 +169,37 @@ class CppGenerator : public BaseGenerator {
       }
     }
 
+    // Generate code for mini reflection.
+    if (parser_.opts.mini_reflect != IDLOptions::kNone) {
+      // To break cyclic dependencies, first pre-declare all tables/structs.
+      for (auto it = parser_.structs_.vec.begin();
+           it != parser_.structs_.vec.end(); ++it) {
+        const auto &struct_def = **it;
+        if (!struct_def.generated) {
+          SetNameSpace(struct_def.defined_namespace);
+          GenMiniReflectPre(&struct_def);
+        }
+      }
+      // Then the unions/enums that may refer to them.
+      for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
+           ++it) {
+        const auto &enum_def = **it;
+        if (!enum_def.generated) {
+          SetNameSpace(enum_def.defined_namespace);
+          GenMiniReflect(nullptr, &enum_def);
+        }
+      }
+      // Then the full tables/structs.
+      for (auto it = parser_.structs_.vec.begin();
+           it != parser_.structs_.vec.end(); ++it) {
+        const auto &struct_def = **it;
+        if (!struct_def.generated) {
+          SetNameSpace(struct_def.defined_namespace);
+          GenMiniReflect(&struct_def, nullptr);
+        }
+      }
+    }
+
     // Generate convenient global helper functions:
     if (parser_.root_struct_def_) {
       auto &struct_def = *parser_.root_struct_def_;
@@ -559,6 +590,140 @@ class CppGenerator : public BaseGenerator {
            (inclass ? " = nullptr" : "") + ") const";
   }
 
+  void GenMiniReflectPre(const StructDef *struct_def) {
+    code_.SetValue("NAME", struct_def->name);
+    code_ += "flatbuffers::TypeTable *{{NAME}}TypeTable();";
+    code_ += "";
+  }
+
+  void GenMiniReflect(const StructDef *struct_def,
+                      const EnumDef *enum_def) {
+    code_.SetValue("NAME", struct_def ? struct_def->name : enum_def->name);
+    code_.SetValue("SEQ_TYPE", struct_def
+                   ? (struct_def->fixed ? "ST_STRUCT" : "ST_TABLE")
+                   : (enum_def->is_union ? "ST_UNION" : "ST_ENUM"));
+    auto num_fields = struct_def
+                      ? struct_def->fields.vec.size()
+                      : enum_def->vals.vec.size();
+    code_.SetValue("NUM_FIELDS", NumToString(num_fields));
+    std::vector<std::string> names;
+    std::vector<Type> types;
+    bool consecutive_enum_from_zero = true;
+    if (struct_def) {
+      for (auto it = struct_def->fields.vec.begin();
+           it != struct_def->fields.vec.end(); ++it) {
+        const auto &field = **it;
+        names.push_back(field.name);
+        types.push_back(field.value.type);
+      }
+    } else {
+      for (auto it = enum_def->vals.vec.begin(); it != enum_def->vals.vec.end();
+           ++it) {
+        const auto &ev = **it;
+        names.push_back(ev.name);
+        types.push_back(enum_def->is_union ? ev.union_type
+                                           : Type(enum_def->underlying_type));
+        if (static_cast<int64_t>(it - enum_def->vals.vec.begin()) != ev.value) {
+          consecutive_enum_from_zero = false;
+        }
+      }
+    }
+    std::string ts;
+    std::vector<std::string> type_refs;
+    for (auto it = types.begin(); it != types.end(); ++it) {
+      auto &type = *it;
+      if (!ts.empty()) ts += ",\n    ";
+      auto is_vector = type.base_type == BASE_TYPE_VECTOR;
+      auto bt = is_vector ? type.element : type.base_type;
+      auto et = IsScalar(bt) || bt == BASE_TYPE_STRING
+                  ? bt - BASE_TYPE_UTYPE + ET_UTYPE
+                  : ET_SEQUENCE;
+      int ref_idx = -1;
+      std::string ref_name = type.struct_def
+                              ? WrapInNameSpace(*type.struct_def)
+                              : type.enum_def
+                                ? WrapInNameSpace(*type.enum_def)
+                                : "";
+      if (!ref_name.empty()) {
+        auto rit = type_refs.begin();
+        for (; rit != type_refs.end(); ++rit) {
+          if (*rit == ref_name) {
+            ref_idx = static_cast<int>(rit - type_refs.begin());
+            break;
+          }
+        }
+        if (rit == type_refs.end()) {
+          ref_idx = static_cast<int>(type_refs.size());
+          type_refs.push_back(ref_name);
+        }
+      }
+      ts += "{ flatbuffers::" + std::string(ElementaryTypeNames()[et]) + ", " +
+            NumToString(is_vector) + ", " + NumToString(ref_idx) + " }";
+    }
+    std::string rs;
+    for (auto it = type_refs.begin(); it != type_refs.end(); ++it) {
+      if (!rs.empty()) rs += ",\n    ";
+      rs += *it + "TypeTable";
+    }
+    std::string ns;
+    for (auto it = names.begin(); it != names.end(); ++it) {
+      if (!ns.empty()) ns += ",\n    ";
+      ns += "\"" + *it + "\"";
+    }
+    std::string vs;
+    if (enum_def && !consecutive_enum_from_zero) {
+      for (auto it = enum_def->vals.vec.begin(); it != enum_def->vals.vec.end();
+           ++it) {
+        const auto &ev = **it;
+        if (!vs.empty()) vs += ", ";
+        vs += NumToString(ev.value);
+      }
+    } else if (struct_def && struct_def->fixed) {
+      for (auto it = struct_def->fields.vec.begin();
+           it != struct_def->fields.vec.end(); ++it) {
+        const auto &field = **it;
+        vs += NumToString(field.value.offset);
+        vs += ", ";
+      }
+      vs += NumToString(struct_def->bytesize);
+    }
+    code_.SetValue("TYPES", ts);
+    code_.SetValue("REFS", rs);
+    code_.SetValue("NAMES", ns);
+    code_.SetValue("VALUES", vs);
+    code_ += "flatbuffers::TypeTable *{{NAME}}TypeTable() {";
+    if (num_fields) {
+      code_ += "  static flatbuffers::TypeCode type_codes[] = {";
+      code_ += "    {{TYPES}}";
+      code_ += "  };";
+    }
+    if (!type_refs.empty()) {
+      code_ += "  static flatbuffers::TypeFunction type_refs[] = {";
+      code_ += "    {{REFS}}";
+      code_ += "  };";
+    }
+    if (!vs.empty()) {
+      code_ += "  static const int32_t values[] = { {{VALUES}} };";
+    }
+    auto has_names = num_fields &&
+           parser_.opts.mini_reflect == IDLOptions::kTypesAndNames;
+    if (has_names) {
+      code_ += "  static const char *names[] = {";
+      code_ += "    {{NAMES}}";
+      code_ += "  };";
+    }
+    code_ += "  static flatbuffers::TypeTable tt = {";
+    code_ += std::string("    flatbuffers::{{SEQ_TYPE}}, {{NUM_FIELDS}}, ") +
+             (num_fields ? "type_codes, " : "nullptr, ") +
+             (!type_refs.empty() ? "type_refs, ": "nullptr, " ) +
+             (!vs.empty() ? "values, " : "nullptr, ") +
+             (has_names ? "names" : "nullptr");
+    code_ += "  };";
+    code_ += "  return &tt;";
+    code_ += "}";
+    code_ += "";
+  }
+
   // Generate an enum declaration,
   // an enum string lookup table,
   // and an enum array of values

tests/generate_code.bat

@@ -15,9 +15,9 @@
 set buildtype=Release
 if "%1"=="-b" set buildtype=%2
 
-..\%buildtype%\flatc.exe --cpp --java --csharp --go --binary --python --js --ts --php --grpc --gen-mutable --gen-object-api --no-includes --cpp-ptr-type flatbuffers::unique_ptr --no-fb-import -I include_test monster_test.fbs monsterdata_test.json
-..\%buildtype%\flatc.exe --cpp --java --csharp --go --binary --python --js --ts --php --gen-mutable --no-fb-import --cpp-ptr-type flatbuffers::unique_ptr  -o namespace_test namespace_test/namespace_test1.fbs namespace_test/namespace_test2.fbs
-..\%buildtype%\flatc.exe --cpp --js --ts --php --gen-mutable --gen-object-api --cpp-ptr-type flatbuffers::unique_ptr -o union_vector ./union_vector/union_vector.fbs
+..\%buildtype%\flatc.exe --cpp --java --csharp --go --binary --python --js --ts --php --grpc --gen-mutable --reflect-names --gen-object-api --no-includes --cpp-ptr-type flatbuffers::unique_ptr --no-fb-import -I include_test monster_test.fbs monsterdata_test.json
+..\%buildtype%\flatc.exe --cpp --java --csharp --go --binary --python --js --ts --php --gen-mutable --reflect-names --no-fb-import --cpp-ptr-type flatbuffers::unique_ptr  -o namespace_test namespace_test/namespace_test1.fbs namespace_test/namespace_test2.fbs
+..\%buildtype%\flatc.exe --cpp --js --ts --php --gen-mutable --reflect-names --gen-object-api --cpp-ptr-type flatbuffers::unique_ptr -o union_vector ./union_vector/union_vector.fbs
 ..\%buildtype%\flatc.exe -b --schema --bfbs-comments -I include_test monster_test.fbs
 ..\%buildtype%\flatc.exe --jsonschema --schema -I include_test monster_test.fbs
 cd ../samples

tests/generate_code.sh

@@ -14,11 +14,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-../flatc --cpp --java --csharp --go --binary --python --js --ts --php --grpc --gen-mutable --gen-object-api --no-includes --cpp-ptr-type flatbuffers::unique_ptr  --no-fb-import -I include_test monster_test.fbs monsterdata_test.json
-../flatc --cpp --java --csharp --go --binary --python --js --ts --php --gen-mutable --no-fb-import --cpp-ptr-type flatbuffers::unique_ptr  -o namespace_test namespace_test/namespace_test1.fbs namespace_test/namespace_test2.fbs
-../flatc --cpp --js --ts --php --gen-mutable --gen-object-api --cpp-ptr-type flatbuffers::unique_ptr -o union_vector ./union_vector/union_vector.fbs
+../flatc --cpp --java --csharp --go --binary --python --js --ts --php --grpc --gen-mutable --reflect-names --gen-object-api --no-includes --cpp-ptr-type flatbuffers::unique_ptr  --no-fb-import -I include_test monster_test.fbs monsterdata_test.json
+../flatc --cpp --java --csharp --go --binary --python --js --ts --php --gen-mutable --reflect-names --no-fb-import --cpp-ptr-type flatbuffers::unique_ptr  -o namespace_test namespace_test/namespace_test1.fbs namespace_test/namespace_test2.fbs
+../flatc --cpp --js --ts --php --gen-mutable --reflect-names --gen-object-api --cpp-ptr-type flatbuffers::unique_ptr -o union_vector ./union_vector/union_vector.fbs
 ../flatc -b --schema --bfbs-comments -I include_test monster_test.fbs
 ../flatc --jsonschema --schema -I include_test monster_test.fbs
 cd ../samples
-../flatc --cpp --gen-mutable --gen-object-api --cpp-ptr-type flatbuffers::unique_ptr monster.fbs
+../flatc --cpp --gen-mutable --reflect-names --gen-object-api --cpp-ptr-type flatbuffers::unique_ptr monster.fbs
 cd ../reflection

tests/monster_test_generated.h

@@ -1899,6 +1899,318 @@ inline void AnyUnion::Reset() {
   type = Any_NONE;
 }
 
+}  // namespace Example
+
+flatbuffers::TypeTable *InParentNamespaceTypeTable();
+
+namespace Example2 {
+
+flatbuffers::TypeTable *MonsterTypeTable();
+
+}  // namespace Example2
+
+namespace Example {
+
+flatbuffers::TypeTable *TestTypeTable();
+
+flatbuffers::TypeTable *TestSimpleTableWithEnumTypeTable();
+
+flatbuffers::TypeTable *Vec3TypeTable();
+
+flatbuffers::TypeTable *AbilityTypeTable();
+
+flatbuffers::TypeTable *StatTypeTable();
+
+flatbuffers::TypeTable *MonsterTypeTable();
+
+flatbuffers::TypeTable *TypeAliasesTypeTable();
+
+flatbuffers::TypeTable *ColorTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_CHAR, 0, 0 },
+    { flatbuffers::ET_CHAR, 0, 0 },
+    { flatbuffers::ET_CHAR, 0, 0 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    ColorTypeTable
+  };
+  static const int32_t values[] = { 1, 2, 8 };
+  static const char *names[] = {
+    "Red",
+    "Green",
+    "Blue"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_ENUM, 3, type_codes, type_refs, values, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *AnyTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_SEQUENCE, 0, -1 },
+    { flatbuffers::ET_SEQUENCE, 0, 0 },
+    { flatbuffers::ET_SEQUENCE, 0, 1 },
+    { flatbuffers::ET_SEQUENCE, 0, 2 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    MonsterTypeTable,
+    TestSimpleTableWithEnumTypeTable,
+    MyGame::Example2::MonsterTypeTable
+  };
+  static const char *names[] = {
+    "NONE",
+    "Monster",
+    "TestSimpleTableWithEnum",
+    "MyGame_Example2_Monster"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_UNION, 4, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
+}  // namespace Example
+
+flatbuffers::TypeTable *InParentNamespaceTypeTable() {
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 0, nullptr, nullptr, nullptr, nullptr
+  };
+  return &tt;
+}
+
+namespace Example2 {
+
+flatbuffers::TypeTable *MonsterTypeTable() {
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 0, nullptr, nullptr, nullptr, nullptr
+  };
+  return &tt;
+}
+
+}  // namespace Example2
+
+namespace Example {
+
+flatbuffers::TypeTable *TestTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_SHORT, 0, -1 },
+    { flatbuffers::ET_CHAR, 0, -1 }
+  };
+  static const int32_t values[] = { 0, 2, 4 };
+  static const char *names[] = {
+    "a",
+    "b"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_STRUCT, 2, type_codes, nullptr, values, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *TestSimpleTableWithEnumTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_CHAR, 0, 0 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    ColorTypeTable
+  };
+  static const char *names[] = {
+    "color"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 1, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *Vec3TypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_FLOAT, 0, -1 },
+    { flatbuffers::ET_FLOAT, 0, -1 },
+    { flatbuffers::ET_FLOAT, 0, -1 },
+    { flatbuffers::ET_DOUBLE, 0, -1 },
+    { flatbuffers::ET_CHAR, 0, 0 },
+    { flatbuffers::ET_SEQUENCE, 0, 1 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    ColorTypeTable,
+    TestTypeTable
+  };
+  static const int32_t values[] = { 0, 4, 8, 16, 24, 26, 32 };
+  static const char *names[] = {
+    "x",
+    "y",
+    "z",
+    "test1",
+    "test2",
+    "test3"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_STRUCT, 6, type_codes, type_refs, values, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *AbilityTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_UINT, 0, -1 },
+    { flatbuffers::ET_UINT, 0, -1 }
+  };
+  static const int32_t values[] = { 0, 4, 8 };
+  static const char *names[] = {
+    "id",
+    "distance"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_STRUCT, 2, type_codes, nullptr, values, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *StatTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_STRING, 0, -1 },
+    { flatbuffers::ET_LONG, 0, -1 },
+    { flatbuffers::ET_USHORT, 0, -1 }
+  };
+  static const char *names[] = {
+    "id",
+    "val",
+    "count"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 3, type_codes, nullptr, nullptr, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *MonsterTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_SEQUENCE, 0, 0 },
+    { flatbuffers::ET_SHORT, 0, -1 },
+    { flatbuffers::ET_SHORT, 0, -1 },
+    { flatbuffers::ET_STRING, 0, -1 },
+    { flatbuffers::ET_BOOL, 0, -1 },
+    { flatbuffers::ET_UCHAR, 1, -1 },
+    { flatbuffers::ET_CHAR, 0, 1 },
+    { flatbuffers::ET_UTYPE, 0, 2 },
+    { flatbuffers::ET_SEQUENCE, 0, 2 },
+    { flatbuffers::ET_SEQUENCE, 1, 3 },
+    { flatbuffers::ET_STRING, 1, -1 },
+    { flatbuffers::ET_SEQUENCE, 1, 4 },
+    { flatbuffers::ET_SEQUENCE, 0, 4 },
+    { flatbuffers::ET_UCHAR, 1, -1 },
+    { flatbuffers::ET_SEQUENCE, 0, 5 },
+    { flatbuffers::ET_BOOL, 0, -1 },
+    { flatbuffers::ET_INT, 0, -1 },
+    { flatbuffers::ET_UINT, 0, -1 },
+    { flatbuffers::ET_LONG, 0, -1 },
+    { flatbuffers::ET_ULONG, 0, -1 },
+    { flatbuffers::ET_INT, 0, -1 },
+    { flatbuffers::ET_UINT, 0, -1 },
+    { flatbuffers::ET_LONG, 0, -1 },
+    { flatbuffers::ET_ULONG, 0, -1 },
+    { flatbuffers::ET_BOOL, 1, -1 },
+    { flatbuffers::ET_FLOAT, 0, -1 },
+    { flatbuffers::ET_FLOAT, 0, -1 },
+    { flatbuffers::ET_FLOAT, 0, -1 },
+    { flatbuffers::ET_STRING, 1, -1 },
+    { flatbuffers::ET_SEQUENCE, 1, 6 },
+    { flatbuffers::ET_UCHAR, 1, -1 },
+    { flatbuffers::ET_SEQUENCE, 1, 3 },
+    { flatbuffers::ET_LONG, 1, -1 },
+    { flatbuffers::ET_DOUBLE, 1, -1 },
+    { flatbuffers::ET_SEQUENCE, 0, 7 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    Vec3TypeTable,
+    ColorTypeTable,
+    AnyTypeTable,
+    TestTypeTable,
+    MonsterTypeTable,
+    StatTypeTable,
+    AbilityTypeTable,
+    MyGame::InParentNamespaceTypeTable
+  };
+  static const char *names[] = {
+    "pos",
+    "mana",
+    "hp",
+    "name",
+    "friendly",
+    "inventory",
+    "color",
+    "test_type",
+    "test",
+    "test4",
+    "testarrayofstring",
+    "testarrayoftables",
+    "enemy",
+    "testnestedflatbuffer",
+    "testempty",
+    "testbool",
+    "testhashs32_fnv1",
+    "testhashu32_fnv1",
+    "testhashs64_fnv1",
+    "testhashu64_fnv1",
+    "testhashs32_fnv1a",
+    "testhashu32_fnv1a",
+    "testhashs64_fnv1a",
+    "testhashu64_fnv1a",
+    "testarrayofbools",
+    "testf",
+    "testf2",
+    "testf3",
+    "testarrayofstring2",
+    "testarrayofsortedstruct",
+    "flex",
+    "test5",
+    "vector_of_longs",
+    "vector_of_doubles",
+    "parent_namespace_test"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 35, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *TypeAliasesTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_CHAR, 0, -1 },
+    { flatbuffers::ET_UCHAR, 0, -1 },
+    { flatbuffers::ET_SHORT, 0, -1 },
+    { flatbuffers::ET_USHORT, 0, -1 },
+    { flatbuffers::ET_INT, 0, -1 },
+    { flatbuffers::ET_UINT, 0, -1 },
+    { flatbuffers::ET_LONG, 0, -1 },
+    { flatbuffers::ET_ULONG, 0, -1 },
+    { flatbuffers::ET_FLOAT, 0, -1 },
+    { flatbuffers::ET_DOUBLE, 0, -1 },
+    { flatbuffers::ET_CHAR, 1, -1 },
+    { flatbuffers::ET_DOUBLE, 1, -1 }
+  };
+  static const char *names[] = {
+    "i8",
+    "u8",
+    "i16",
+    "u16",
+    "i32",
+    "u32",
+    "i64",
+    "u64",
+    "f32",
+    "f64",
+    "v8",
+    "vf64"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 12, type_codes, nullptr, nullptr, names
+  };
+  return &tt;
+}
+
 inline const MyGame::Example::Monster *GetMonster(const void *buf) {
   return flatbuffers::GetRoot<MyGame::Example::Monster>(buf);
 }

tests/namespace_test/namespace_test1_generated.h

@@ -119,6 +119,59 @@ inline flatbuffers::Offset<TableInNestedNS> CreateTableInNestedNS(
   return builder_.Finish();
 }
 
+flatbuffers::TypeTable *TableInNestedNSTypeTable();
+
+flatbuffers::TypeTable *StructInNestedNSTypeTable();
+
+flatbuffers::TypeTable *EnumInNestedNSTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_CHAR, 0, 0 },
+    { flatbuffers::ET_CHAR, 0, 0 },
+    { flatbuffers::ET_CHAR, 0, 0 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    EnumInNestedNSTypeTable
+  };
+  static const char *names[] = {
+    "A",
+    "B",
+    "C"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_ENUM, 3, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *TableInNestedNSTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_INT, 0, -1 }
+  };
+  static const char *names[] = {
+    "foo"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 1, type_codes, nullptr, nullptr, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *StructInNestedNSTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_INT, 0, -1 },
+    { flatbuffers::ET_INT, 0, -1 }
+  };
+  static const int32_t values[] = { 0, 4, 8 };
+  static const char *names[] = {
+    "a",
+    "b"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_STRUCT, 2, type_codes, nullptr, values, names
+  };
+  return &tt;
+}
+
 }  // namespace NamespaceB
 }  // namespace NamespaceA
 

tests/namespace_test/namespace_test2_generated.h

@@ -212,6 +212,85 @@ namespace NamespaceC {
 
 namespace NamespaceA {
 
+flatbuffers::TypeTable *TableInFirstNSTypeTable();
+
+}  // namespace NamespaceA
+
+namespace NamespaceC {
+
+flatbuffers::TypeTable *TableInCTypeTable();
+
+}  // namespace NamespaceC
+
+namespace NamespaceA {
+
+flatbuffers::TypeTable *SecondTableInATypeTable();
+
+flatbuffers::TypeTable *TableInFirstNSTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_SEQUENCE, 0, 0 },
+    { flatbuffers::ET_CHAR, 0, 1 },
+    { flatbuffers::ET_SEQUENCE, 0, 2 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    NamespaceA::NamespaceB::TableInNestedNSTypeTable,
+    NamespaceA::NamespaceB::EnumInNestedNSTypeTable,
+    NamespaceA::NamespaceB::StructInNestedNSTypeTable
+  };
+  static const char *names[] = {
+    "foo_table",
+    "foo_enum",
+    "foo_struct"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 3, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
+}  // namespace NamespaceA
+
+namespace NamespaceC {
+
+flatbuffers::TypeTable *TableInCTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_SEQUENCE, 0, 0 },
+    { flatbuffers::ET_SEQUENCE, 0, 1 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    NamespaceA::TableInFirstNSTypeTable,
+    NamespaceA::SecondTableInATypeTable
+  };
+  static const char *names[] = {
+    "refer_to_a1",
+    "refer_to_a2"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 2, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
+}  // namespace NamespaceC
+
+namespace NamespaceA {
+
+flatbuffers::TypeTable *SecondTableInATypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_SEQUENCE, 0, 0 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    NamespaceC::TableInCTypeTable
+  };
+  static const char *names[] = {
+    "refer_to_c"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 1, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
 }  // namespace NamespaceA
 
 #endif  // FLATBUFFERS_GENERATED_NAMESPACETEST2_NAMESPACEA_H_

tests/test.cpp

@@ -18,6 +18,7 @@
 #include "flatbuffers/idl.h"
 #include "flatbuffers/util.h"
 #include "flatbuffers/registry.h"
+#include "flatbuffers/minireflect.h"
 
 #include "monster_test_generated.h"
 #include "namespace_test/namespace_test1_generated.h"
@@ -46,8 +47,9 @@ int testing_fails = 0;
 
 void TestFail(const char *expval, const char *val, const char *exp,
               const char *file, int line) {
-  TEST_OUTPUT_LINE("TEST FAILED: %s:%d, %s (%s) != %s", file, line,
-                   exp, expval, val);
+  TEST_OUTPUT_LINE("VALUE: \"%s\"", expval);
+  TEST_OUTPUT_LINE("EXPECTED: \"%s\"", val);
+  TEST_OUTPUT_LINE("TEST FAILED: %s:%d, %s", file, line, exp);
   assert(0);
   testing_fails++;
 }
@@ -561,11 +563,7 @@ void ParseAndGenerateTextTest() {
   std::string jsongen;
   auto result = GenerateText(parser, parser.builder_.GetBufferPointer(), &jsongen);
   TEST_EQ(result, true);
-
-  if (jsongen != jsonfile) {
-    TEST_OUTPUT_LINE("%s----------------\n%s", jsongen.c_str(), jsonfile.c_str());
-    TEST_NOTNULL(NULL);
-  }
+  TEST_EQ_STR(jsongen.c_str(), jsonfile.c_str());
 
   // We can also do the above using the convenient Registry that knows about
   // a set of file_identifiers mapped to schemas.
@@ -772,6 +770,34 @@ void ReflectionTest(uint8_t *flatbuf, size_t length) {
                               fbb.GetBufferPointer(), fbb.GetSize()), true);
 }
 
+void MiniReflectFlatBuffersTest(uint8_t *flatbuf) {
+  auto s = flatbuffers::FlatBufferToString(flatbuf, MonsterTypeTable());
+  TEST_EQ_STR(s.c_str(),
+    "{ "
+    "pos: { x: 1.0, y: 2.0, z: 3.0, test1: 0.0, test2: Red, test3: "
+      "{ a: 10, b: 20 } }, "
+    "hp: 80, "
+    "name: \"MyMonster\", "
+    "inventory: [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ], "
+    "test_type: Monster, "
+    "test: { name: \"Fred\" }, "
+    "test4: [ { a: 10, b: 20 }, { a: 30, b: 40 } ], "
+    "testarrayofstring: [ \"bob\", \"fred\", \"bob\", \"fred\" ], "
+    "testarrayoftables: [ { hp: 1000, name: \"Barney\" }, { name: \"Fred\" }, "
+      "{ name: \"Wilma\" } ], "
+    // TODO(wvo): should really print this nested buffer correctly.
+    "testnestedflatbuffer: [ 20, 0, 0, 0, 77, 79, 78, 83, 12, 0, 12, 0, 0, 0, "
+      "4, 0, 6, 0, 8, 0, 12, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 13, 0, 0, 0, 78, "
+      "101, 115, 116, 101, 100, 77, 111, 110, 115, 116, 101, 114, 0, 0, 0 ], "
+    "testarrayofstring2: [ \"jane\", \"mary\" ], "
+    "testarrayofsortedstruct: [ { id: 1, distance: 10 }, "
+      "{ id: 2, distance: 20 }, { id: 3, distance: 30 }, "
+      "{ id: 4, distance: 40 } ], "
+    "flex: [ 210, 4, 5, 2 ], "
+    "test5: [ { a: 10, b: 20 }, { a: 30, b: 40 } ] "
+    "}");
+}
+
 // Parse a .proto schema, output as .fbs
 void ParseProtoTest() {
   // load the .proto and the golden file from disk
@@ -800,11 +826,7 @@ void ParseProtoTest() {
   // Ensure generated file is parsable.
   flatbuffers::Parser parser2;
   TEST_EQ(parser2.Parse(fbs.c_str(), nullptr), true);
-
-  if (fbs != goldenfile) {
-    TEST_OUTPUT_LINE("%s----------------\n%s", fbs.c_str(), goldenfile.c_str());
-    TEST_NOTNULL(NULL);
-  }
+  TEST_EQ_STR(fbs.c_str(), goldenfile.c_str());
 }
 
 template<typename T> void CompareTableFieldValue(flatbuffers::Table *table,
@@ -1248,10 +1270,9 @@ void UnicodeTest() {
   parser.opts.indent_step = -1;
   auto result = GenerateText(parser, parser.builder_.GetBufferPointer(), &jsongen);
   TEST_EQ(result, true);
-  TEST_EQ(jsongen,
-          std::string(
+  TEST_EQ_STR(jsongen.c_str(),
             "{F: \"\\u20AC\\u00A2\\u30E6\\u30FC\\u30B6\\u30FC"
-            "\\u5225\\u30B5\\u30A4\\u30C8\\u20AC\\u0080\\uD83D\\uDE0E\"}"));
+            "\\u5225\\u30B5\\u30A4\\u30C8\\u20AC\\u0080\\uD83D\\uDE0E\"}");
 }
 
 void UnicodeTestAllowNonUTF8() {
@@ -1265,10 +1286,9 @@ void UnicodeTestAllowNonUTF8() {
   parser.opts.indent_step = -1;
   auto result = GenerateText(parser, parser.builder_.GetBufferPointer(), &jsongen);
   TEST_EQ(result, true);
-  TEST_EQ(jsongen,
-          std::string(
+  TEST_EQ_STR(jsongen.c_str(),
             "{F: \"\\u20AC\\u00A2\\u30E6\\u30FC\\u30B6\\u30FC"
-            "\\u5225\\u30B5\\u30A4\\u30C8\\u0001\\x80\\u0080\\uD83D\\uDE0E\"}"));
+            "\\u5225\\u30B5\\u30A4\\u30C8\\u0001\\x80\\u0080\\uD83D\\uDE0E\"}");
 }
 
 void UnicodeTestGenerateTextFailsOnNonUTF8() {
@@ -1300,7 +1320,7 @@ void UnicodeSurrogatesTest() {
     parser.builder_.GetBufferPointer());
   auto string = root->GetPointer<flatbuffers::String *>(
     flatbuffers::FieldIndexToOffset(0));
-  TEST_EQ(strcmp(string->c_str(), "\xF0\x9F\x92\xA9"), 0);
+  TEST_EQ_STR(string->c_str(), "\xF0\x9F\x92\xA9");
 }
 
 void UnicodeInvalidSurrogatesTest() {
@@ -1437,7 +1457,7 @@ void UnknownFieldsTest() {
   parser.opts.indent_step = -1;
   auto result = GenerateText(parser, parser.builder_.GetBufferPointer(), &jsongen);
   TEST_EQ(result, true);
-  TEST_EQ(jsongen == "{str: \"test\",i: 10}", true);
+  TEST_EQ_STR(jsongen.c_str(), "{str: \"test\",i: 10}");
 }
 
 void ParseUnionTest() {
@@ -1548,6 +1568,14 @@ void UnionVectorTest() {
   auto repacked_movie = GetMovie(fbb.GetBufferPointer());
 
   TestMovie(repacked_movie);
+
+  auto s = flatbuffers::FlatBufferToString(fbb.GetBufferPointer(),
+                                           MovieTypeTable());
+  TEST_EQ_STR(s.c_str(),
+    "{ main_character_type: Rapunzel, main_character: { hair_length: 6 }, "
+    "characters_type: [ Belle, MuLan, BookFan, Other, Unused ], "
+    "characters: [ { books_read: 7 }, { sword_attack_damage: 5 }, "
+    "{ books_read: 2 }, \"Other\", \"Unused\" ] }");
 }
 
 void ConformTest() {
@@ -1774,6 +1802,8 @@ int main(int /*argc*/, const char * /*argv*/[]) {
 
   ObjectFlatBuffersTest(flatbuf.data());
 
+  MiniReflectFlatBuffersTest(flatbuf.data());
+
   SizePrefixedTest();
 
   #ifndef FLATBUFFERS_NO_FILE_TESTS

tests/union_vector/union_vector_generated.h

@@ -600,6 +600,107 @@ inline void CharacterUnion::Reset() {
   type = Character_NONE;
 }
 
+flatbuffers::TypeTable *AttackerTypeTable();
+
+flatbuffers::TypeTable *RapunzelTypeTable();
+
+flatbuffers::TypeTable *BookReaderTypeTable();
+
+flatbuffers::TypeTable *MovieTypeTable();
+
+flatbuffers::TypeTable *CharacterTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_SEQUENCE, 0, -1 },
+    { flatbuffers::ET_SEQUENCE, 0, 0 },
+    { flatbuffers::ET_SEQUENCE, 0, 1 },
+    { flatbuffers::ET_SEQUENCE, 0, 2 },
+    { flatbuffers::ET_SEQUENCE, 0, 2 },
+    { flatbuffers::ET_STRING, 0, -1 },
+    { flatbuffers::ET_STRING, 0, -1 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    AttackerTypeTable,
+    RapunzelTypeTable,
+    BookReaderTypeTable
+  };
+  static const char *names[] = {
+    "NONE",
+    "MuLan",
+    "Rapunzel",
+    "Belle",
+    "BookFan",
+    "Other",
+    "Unused"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_UNION, 7, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *AttackerTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_INT, 0, -1 }
+  };
+  static const char *names[] = {
+    "sword_attack_damage"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 1, type_codes, nullptr, nullptr, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *RapunzelTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_INT, 0, -1 }
+  };
+  static const int32_t values[] = { 0, 4 };
+  static const char *names[] = {
+    "hair_length"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_STRUCT, 1, type_codes, nullptr, values, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *BookReaderTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_INT, 0, -1 }
+  };
+  static const int32_t values[] = { 0, 4 };
+  static const char *names[] = {
+    "books_read"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_STRUCT, 1, type_codes, nullptr, values, names
+  };
+  return &tt;
+}
+
+flatbuffers::TypeTable *MovieTypeTable() {
+  static flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_UTYPE, 0, 0 },
+    { flatbuffers::ET_SEQUENCE, 0, 0 },
+    { flatbuffers::ET_UTYPE, 1, 0 },
+    { flatbuffers::ET_SEQUENCE, 1, 0 }
+  };
+  static flatbuffers::TypeFunction type_refs[] = {
+    CharacterTypeTable
+  };
+  static const char *names[] = {
+    "main_character_type",
+    "main_character",
+    "characters_type",
+    "characters"
+  };
+  static flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 4, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
 inline const Movie *GetMovie(const void *buf) {
   return flatbuffers::GetRoot<Movie>(buf);
 }