Port FlatBuffers to Go.

Implement code generation and runtime library for Go, derived from the
Java implementation. Additionally, the test suite verifies:

 - the exact bytes in the Builder buffer during object construction,
 - vtable deduplication, and
 - table construction, via a fuzzer derived from the C++ implementation.

Change-Id: Ib95a019c684891def2b50281e570b4843fea7baa

src/idl_gen_go.cpp

@@ -0,0 +1,680 @@
+/*
+ * Copyright 2014 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.
+ */
+
+// independent from idl_parser, since this code is not needed for most clients
+
+#include <string>
+
+#include "flatbuffers/flatbuffers.h"
+#include "flatbuffers/idl.h"
+#include "flatbuffers/util.h"
+
+#ifdef _WIN32
+#include <direct.h>
+#define PATH_SEPARATOR "\\"
+#define mkdir(n, m) _mkdir(n)
+#else
+#include <sys/stat.h>
+#define PATH_SEPARATOR "/"
+#endif
+
+namespace flatbuffers {
+namespace go {
+
+static std::string GenGetter(const Type &type);
+static std::string GenMethod(const FieldDef &field);
+static void GenStructBuilder(const StructDef &struct_def,
+                             std::string *code_ptr);
+static void GenReceiver(const StructDef &struct_def, std::string *code_ptr);
+static std::string GenTypeBasic(const Type &type);
+static std::string GenTypeGet(const Type &type);
+static std::string TypeName(const FieldDef &field);
+
+
+// Write a comment.
+static void Comment(const std::string &dc,
+                       std::string *code_ptr,
+                       const char *prefix = "") {
+  std::string &code = *code_ptr;
+  if (dc.length()) {
+    code += std::string(prefix) + "///" + dc + "\n";
+  }
+}
+
+// Most field accessors need to retrieve and test the field offset first,
+// this is the prefix code for that.
+std::string OffsetPrefix(const FieldDef &field) {
+  return "{\n\to := flatbuffers.UOffsetT(rcv._tab.Offset(" +
+         NumToString(field.value.offset) +
+         "))\n\tif o != 0 {\n";
+}
+
+// Begin by declaring namespace and imports.
+static void BeginFile(const std::string name_space_name,
+                      const bool needs_imports,
+                      std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += "// automatically generated, do not modify\n\n";
+  code += "package " + name_space_name + "\n\n";
+  if (needs_imports) {
+    code += "import (\n";
+    code += "\tflatbuffers \"github.com/google/flatbuffers/go\"\n";
+    code += ")\n";
+  }
+}
+
+// Begin a class declaration.
+static void BeginClass(const StructDef &struct_def, std::string *code_ptr) {
+  std::string &code = *code_ptr;
+
+  code += "type " + struct_def.name + " struct {\n\t";
+
+  // _ is reserved in flatbuffers field names, so no chance of name conflict:
+  code += "_tab ";
+  code += struct_def.fixed ? "flatbuffers.Struct" : "flatbuffers.Table";
+  code += "\n}\n\n";
+}
+
+// Begin enum code with a class declaration.
+static void BeginEnum(std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += "const (\n";
+}
+
+// A single enum member.
+static void EnumMember(const EnumDef &enum_def, const EnumVal ev,
+                       std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += "\t";
+  code += enum_def.name;
+  code += ev.name;
+  code += " = ";
+  code += NumToString(ev.value) + "\n";
+}
+
+// End enum code.
+static void EndEnum(std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += ")\n";
+}
+
+// Initialize a new struct or table from existing data.
+static void NewRootTypeFromBuffer(const StructDef &struct_def,
+                                  std::string *code_ptr) {
+  std::string &code = *code_ptr;
+
+  code += "func GetRootAs";
+  code += struct_def.name;
+  code += "(buf []byte, offset flatbuffers.UOffsetT) ";
+  code += "*" + struct_def.name + "";
+  code += " {\n";
+  code += "\tn := flatbuffers.GetUOffsetT(buf[offset:])\n";
+  code += "\tx := &" + struct_def.name + "{}\n";
+  code += "\tx.Init(buf, n + offset)\n";
+  code += "\treturn x\n";
+  code += "}\n\n";
+}
+
+// Initialize an existing object with other data, to avoid an allocation.
+static void InitializeExisting(const StructDef &struct_def,
+                               std::string *code_ptr) {
+  std::string &code = *code_ptr;
+
+  GenReceiver(struct_def, code_ptr);
+  code += " Init(buf []byte, i flatbuffers.UOffsetT) ";
+  code += "{\n";
+  code += "\trcv._tab.Bytes = buf\n";
+  code += "\trcv._tab.Pos = i\n";
+  code += "}\n\n";
+}
+
+// Get the length of a vector.
+static void GetVectorLen(const StructDef &struct_def,
+                         const FieldDef &field,
+                         std::string *code_ptr) {
+  std::string &code = *code_ptr;
+
+  GenReceiver(struct_def, code_ptr);
+  code += " " + MakeCamel(field.name) + "Length(";
+  code += ") int " + OffsetPrefix(field);
+  code += "\t\treturn rcv._tab.VectorLen(o)\n\t}\n";
+  code += "\treturn 0\n}\n\n";
+}
+
+// Get the value of a struct's scalar.
+static void GetScalarFieldOfStruct(const StructDef &struct_def,
+                                   const FieldDef &field,
+                                   std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  std::string getter = GenGetter(field.value.type);
+  GenReceiver(struct_def, code_ptr);
+  code += " " + MakeCamel(field.name);
+  code += "() " + TypeName(field) + " { return " + getter;
+  code += "(rcv._tab.Pos + flatbuffers.UOffsetT(";
+  code += NumToString(field.value.offset) + ")) }\n";
+}
+
+// Get the value of a table's scalar.
+static void GetScalarFieldOfTable(const StructDef &struct_def,
+                                  const FieldDef &field,
+                                  std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  std::string getter = GenGetter(field.value.type);
+  GenReceiver(struct_def, code_ptr);
+  code += " " + MakeCamel(field.name);
+  code += "() " + TypeName(field) + " ";
+  code += OffsetPrefix(field) + "\t\treturn " + getter;
+  code += "(o + rcv._tab.Pos)\n\t}\n";
+  code += "\treturn " + field.value.constant + "\n";
+  code += "}\n\n";
+}
+
+// Get a struct by initializing an existing struct.
+// Specific to Struct.
+static void GetStructFieldOfStruct(const StructDef &struct_def,
+                                   const FieldDef &field,
+                                   std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  GenReceiver(struct_def, code_ptr);
+  code += " " + MakeCamel(field.name);
+  code += "(obj *" + TypeName(field);
+  code += ") *" + TypeName(field);
+  code += " {\n";
+  code += "\tif obj == nil {\n";
+  code += "\t\tobj = new(" + TypeName(field) + ")\n";
+  code += "\t}\n";
+  code += "\tobj.Init(rcv._tab.Bytes, rcv._tab.Pos + ";
+  code += NumToString(field.value.offset) + ")";
+  code += "\n\treturn obj\n";
+  code += "}\n";
+}
+
+// Get a struct by initializing an existing struct.
+// Specific to Table.
+static void GetStructFieldOfTable(const StructDef &struct_def,
+                                  const FieldDef &field,
+                                  std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  GenReceiver(struct_def, code_ptr);
+  code += " " + MakeCamel(field.name);
+  code += "(obj *";
+  code += TypeName(field);
+  code += ") *" + TypeName(field) + " " + OffsetPrefix(field);
+  if (field.value.type.struct_def->fixed) {
+    code += "\t\tx := o + rcv._tab.Pos\n";
+  } else {
+    code += "\t\tx := rcv._tab.Indirect(o + rcv._tab.Pos)\n";
+  }
+  code += "\t\tif obj == nil {\n";
+  code += "\t\t\tobj = new(" + TypeName(field) + ")\n";
+  code += "\t\t}\n";
+  code += "\t\tobj.Init(rcv._tab.Bytes, x)\n";
+  code += "\t\treturn obj\n\t}\n\treturn nil\n";
+  code += "}\n\n";
+}
+
+// Get the value of a string.
+static void GetStringField(const StructDef &struct_def,
+                           const FieldDef &field,
+                           std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  GenReceiver(struct_def, code_ptr);
+  code += " " +  MakeCamel(field.name);
+  code += "() " + TypeName(field) + " ";
+  code += OffsetPrefix(field) + "\t\treturn " + GenGetter(field.value.type);
+  code += "(o)\n\t}\n\treturn \"\"\n";
+  code += "}\n\n";
+}
+
+// Get the value of a union from an object.
+static void GetUnionField(const StructDef &struct_def,
+                          const FieldDef &field,
+                          std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  GenReceiver(struct_def, code_ptr);
+  code += " " + MakeCamel(field.name) + "(";
+  code += "obj " + TypeName(field) + ") bool ";
+  code += OffsetPrefix(field);
+  code += "\t\t" + GenGetter(field.value.type);
+  code += "(obj, o)\n\t\treturn true\n\t}\n";
+  code += "\treturn false\n";
+  code += "}\n\n";
+}
+
+// Get the value of a vector's struct member.
+static void GetMemberOfVectorOfStruct(const StructDef &struct_def,
+                                      const FieldDef &field,
+                                      std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  auto vectortype = field.value.type.VectorType();
+
+  GenReceiver(struct_def, code_ptr);
+  code += " " + MakeCamel(field.name);
+  code += "(obj *" + TypeName(field);
+  code += ", j int) bool " + OffsetPrefix(field);
+  code += "\t\tx := rcv._tab.Vector(o)\n";
+  code += "\t\tx += flatbuffers.UOffsetT(j) * ";
+  code += NumToString(InlineSize(vectortype)) + "\n";
+  if (!(vectortype.struct_def->fixed)) {
+    code += "\t\tx = rcv._tab.Indirect(x)\n";
+  }
+  code += "\tif obj == nil {\n";
+  code += "\t\tobj = new(" + TypeName(field) + ")\n";
+  code += "\t}\n";
+  code += "\t\tobj.Init(rcv._tab.Bytes, x)\n";
+  code += "\t\treturn true\n\t}\n";
+  code += "\treturn false\n";
+  code += "}\n\n";
+}
+
+// Get the value of a vector's non-struct member. Uses a named return
+// argument to conveniently set the zero value for the result.
+static void GetMemberOfVectorOfNonStruct(const StructDef &struct_def,
+                                         const FieldDef &field,
+                                         std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  auto vectortype = field.value.type.VectorType();
+
+  GenReceiver(struct_def, code_ptr);
+  code += " " + MakeCamel(field.name);
+  code += "(j int) " + TypeName(field) + " ";
+  code += OffsetPrefix(field);
+  code += "\t\ta := rcv._tab.Vector(o)\n";
+  code += "\t\treturn " + GenGetter(field.value.type) + "(";
+  code += "a + flatbuffers.UOffsetT(j * ";
+  code += NumToString(InlineSize(vectortype)) + "))\n";
+  code += "\t}\n";
+  if (vectortype.base_type == BASE_TYPE_STRING) {
+    code += "\treturn \"\"\n";
+  } else {
+    code += "\treturn 0\n";
+  }
+  code += "}\n\n";
+}
+
+// Begin the creator function signature.
+static void BeginBuilderArgs(const StructDef &struct_def,
+                             std::string *code_ptr) {
+  std::string &code = *code_ptr;
+
+  code += "\n";
+  code += "func Create" + struct_def.name;
+  code += "(builder *flatbuffers.Builder";
+}
+
+// Recursively generate arguments for a constructor, to deal with nested
+// structs.
+static void StructBuilderArgs(const StructDef &struct_def,
+                              const char *nameprefix,
+                              std::string *code_ptr) {
+  for (auto it = struct_def.fields.vec.begin();
+       it != struct_def.fields.vec.end();
+       ++it) {
+    auto &field = **it;
+    if (IsStruct(field.value.type)) {
+      // Generate arguments for a struct inside a struct. To ensure names
+      // don't clash, and to make it obvious these arguments are constructing
+      // a nested struct, prefix the name with the struct name.
+      StructBuilderArgs(*field.value.type.struct_def,
+                        (field.value.type.struct_def->name + "_").c_str(),
+                        code_ptr);
+    } else {
+      std::string &code = *code_ptr;
+      code += (std::string)", " + nameprefix;
+      code += MakeCamel(field.name, false);
+      code += " " + GenTypeBasic(field.value.type);
+    }
+  }
+}
+
+// End the creator function signature.
+static void EndBuilderArgs(std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += ") flatbuffers.UOffsetT {\n";
+}
+
+// Recursively generate struct construction statements and instert manual
+// padding.
+static void StructBuilderBody(const StructDef &struct_def,
+                              const char *nameprefix,
+                              std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += "    builder.Prep(" + NumToString(struct_def.minalign) + ", ";
+  code += NumToString(struct_def.bytesize) + ")\n";
+  for (auto it = struct_def.fields.vec.rbegin();
+       it != struct_def.fields.vec.rend();
+       ++it) {
+    auto &field = **it;
+    if (field.padding)
+      code += "    builder.Pad(" + NumToString(field.padding) + ")\n";
+    if (IsStruct(field.value.type)) {
+      StructBuilderBody(*field.value.type.struct_def,
+                        (field.value.type.struct_def->name + "_").c_str(),
+                        code_ptr);
+    } else {
+      code += "    builder.Prepend" + GenMethod(field) + "(";
+      code += nameprefix + MakeCamel(field.name, false) + ")\n";
+    }
+  }
+}
+
+static void EndBuilderBody(std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += "    return builder.Offset()\n";
+  code += "}\n";
+}
+
+// Get the value of a table's starting offset.
+static void GetStartOfTable(const StructDef &struct_def,
+                            std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += "func " + struct_def.name + "Start";
+  code += "(builder *flatbuffers.Builder) { ";
+  code += "builder.StartObject(";
+  code += NumToString(struct_def.fields.vec.size());
+  code += ") }\n";
+}
+
+// Set the value of a table's field.
+static void BuildFieldOfTable(const StructDef &struct_def,
+                              const FieldDef &field,
+                              const size_t offset,
+                              std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += "func " + struct_def.name + "Add" + MakeCamel(field.name);
+  code += "(builder *flatbuffers.Builder, ";
+  code += MakeCamel(field.name, false) + " ";
+  if (!IsScalar(field.value.type.base_type) && (!struct_def.fixed)) {
+    code += "flatbuffers.UOffsetT";
+  } else {
+    code += GenTypeBasic(field.value.type);
+  }
+  code += ") ";
+  code += "{ builder.Prepend";
+  code += GenMethod(field) + "Slot(";
+  code += NumToString(offset) + ", ";
+  if (!IsScalar(field.value.type.base_type) && (!struct_def.fixed)) {
+    code += "flatbuffers.UOffsetT";
+    code += "(";
+    code += MakeCamel(field.name, false) + ")";
+  } else {
+    code += MakeCamel(field.name, false);
+  }
+  code += ", " + field.value.constant;
+  code += ") }\n";
+}
+
+// Set the value of one of the members of a table's vector.
+static void BuildVectorOfTable(const StructDef &struct_def,
+                               const FieldDef &field,
+                               std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += "func " + struct_def.name + "Start";
+  code += MakeCamel(field.name);
+  code += "Vector(builder *flatbuffers.Builder, numElems int) ";
+  code += "flatbuffers.UOffsetT { return builder.StartVector(";
+  code += NumToString(InlineSize(field.value.type.VectorType()));
+  code += ", numElems) }\n";
+}
+
+// Get the offset of the end of a table.
+static void GetEndOffsetOnTable(const StructDef &struct_def,
+                                std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += "func " + struct_def.name + "End";
+  code += "(builder *flatbuffers.Builder) flatbuffers.UOffsetT ";
+  code += "{ return builder.EndObject() }\n";
+}
+
+// Generate the receiver for function signatures.
+static void GenReceiver(const StructDef &struct_def, std::string *code_ptr) {
+  std::string &code = *code_ptr;
+  code += "func (rcv *" + struct_def.name + ")";
+}
+
+// Generate a struct field, conditioned on its child type(s).
+static void GenStructAccessor(const StructDef &struct_def,
+                              const FieldDef &field,
+                              std::string *code_ptr) {
+  Comment(field.doc_comment, code_ptr, "");
+  if (IsScalar(field.value.type.base_type)) {
+    if (struct_def.fixed) {
+      GetScalarFieldOfStruct(struct_def, field, code_ptr);
+    } else {
+      GetScalarFieldOfTable(struct_def, field, code_ptr);
+    }
+  } else {
+    switch (field.value.type.base_type) {
+      case BASE_TYPE_STRUCT:
+        if (struct_def.fixed) {
+          GetStructFieldOfStruct(struct_def, field, code_ptr);
+        } else {
+          GetStructFieldOfTable(struct_def, field, code_ptr);
+        }
+        break;
+      case BASE_TYPE_STRING:
+        GetStringField(struct_def, field, code_ptr);
+        break;
+      case BASE_TYPE_VECTOR: {
+        auto vectortype = field.value.type.VectorType();
+        if (vectortype.base_type == BASE_TYPE_STRUCT) {
+          GetMemberOfVectorOfStruct(struct_def, field, code_ptr);
+        } else {
+          GetMemberOfVectorOfNonStruct(struct_def, field, code_ptr);
+        }
+        break;
+      }
+      case BASE_TYPE_UNION:
+        GetUnionField(struct_def, field, code_ptr);
+        break;
+      default:
+        assert(0);
+    }
+  }
+  if (field.value.type.base_type == BASE_TYPE_VECTOR) {
+    GetVectorLen(struct_def, field, code_ptr);
+  }
+}
+
+// Generate table constructors, conditioned on its members' types.
+static void GenTableBuilders(const StructDef &struct_def,
+                             std::string *code_ptr) {
+  GetStartOfTable(struct_def, code_ptr);
+
+  for (auto it = struct_def.fields.vec.begin();
+       it != struct_def.fields.vec.end();
+       ++it) {
+    auto &field = **it;
+    if (field.deprecated) continue;
+
+    auto offset = it - struct_def.fields.vec.begin();
+    BuildFieldOfTable(struct_def, field, offset, code_ptr);
+    if (field.value.type.base_type == BASE_TYPE_VECTOR) {
+      BuildVectorOfTable(struct_def, field, code_ptr);
+    }
+  }
+
+  GetEndOffsetOnTable(struct_def, code_ptr);
+}
+
+// Generate struct or table methods.
+static void GenStruct(const StructDef &struct_def,
+                      std::string *code_ptr,
+                      StructDef *root_struct_def) {
+  if (struct_def.generated) return;
+
+  Comment(struct_def.doc_comment, code_ptr);
+  BeginClass(struct_def, code_ptr);
+  if (&struct_def == root_struct_def) {
+    // Generate a special accessor for the table that has been declared as
+    // the root type.
+    NewRootTypeFromBuffer(struct_def, code_ptr);
+  }
+  // Generate the Init method that sets the field in a pre-existing
+  // accessor object. This is to allow object reuse.
+  InitializeExisting(struct_def, code_ptr);
+  for (auto it = struct_def.fields.vec.begin();
+       it != struct_def.fields.vec.end();
+       ++it) {
+    auto &field = **it;
+    if (field.deprecated) continue;
+
+    GenStructAccessor(struct_def, field, code_ptr);
+  }
+
+  if (struct_def.fixed) {
+    // create a struct constructor function
+    GenStructBuilder(struct_def, code_ptr);
+  } else {
+    // Create a set of functions that allow table construction.
+    GenTableBuilders(struct_def, code_ptr);
+  }
+}
+
+// Generate enum declarations.
+static void GenEnum(const EnumDef &enum_def, std::string *code_ptr) {
+  if (enum_def.generated) return;
+
+  Comment(enum_def.doc_comment, code_ptr);
+  BeginEnum(code_ptr);
+  for (auto it = enum_def.vals.vec.begin();
+       it != enum_def.vals.vec.end();
+       ++it) {
+    auto &ev = **it;
+    Comment(ev.doc_comment, code_ptr, "  ");
+    EnumMember(enum_def, ev, code_ptr);
+  }
+  EndEnum(code_ptr);
+}
+
+// Returns the function name that is able to read a value of the given type.
+static std::string GenGetter(const Type &type) {
+  switch (type.base_type) {
+    case BASE_TYPE_STRING: return "rcv._tab.String";
+    case BASE_TYPE_UNION: return "rcv._tab.Union";
+    case BASE_TYPE_VECTOR: return GenGetter(type.VectorType());
+    default:
+      return "rcv._tab.Get" + MakeCamel(GenTypeGet(type));
+  }
+}
+
+// Returns the method name for use with add/put calls.
+static std::string GenMethod(const FieldDef &field) {
+  return IsScalar(field.value.type.base_type)
+    ? MakeCamel(GenTypeBasic(field.value.type))
+    : (IsStruct(field.value.type) ? "Struct" : "UOffsetT");
+}
+
+
+// Save out the generated code for a Go Table type.
+static bool SaveType(const Parser &parser, const Definition &def,
+                     const std::string &classcode, const std::string &path,
+                     bool needs_imports) {
+  if (!classcode.length()) return true;
+
+  std::string name_space_name;
+  std::string name_space_dir = path;
+  for (auto it = parser.name_space_.begin();
+        it != parser.name_space_.end(); ++it) {
+    if (name_space_name.length()) {
+      name_space_name += ".";
+      name_space_dir += PATH_SEPARATOR;
+    }
+    name_space_name = *it;
+    name_space_dir += *it;
+    mkdir(name_space_dir.c_str(), S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
+  }
+
+
+  std::string code = "";
+  BeginFile(name_space_name, needs_imports, &code);
+  code += classcode;
+  std::string filename = name_space_dir + PATH_SEPARATOR + def.name + ".go";
+  return SaveFile(filename.c_str(), code, false);
+}
+
+static std::string GenTypeBasic(const Type &type) {
+  static const char *ctypename[] = {
+    #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE) #GTYPE,
+      FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+    #undef FLATBUFFERS_TD
+  };
+  return ctypename[type.base_type];
+}
+
+static std::string GenTypePointer(const Type &type) {
+  switch (type.base_type) {
+    case BASE_TYPE_STRING:
+      return "string";
+    case BASE_TYPE_VECTOR:
+      return GenTypeGet(type.VectorType());
+    case BASE_TYPE_STRUCT:
+      return type.struct_def->name;
+    case BASE_TYPE_UNION:
+      // fall through
+    default:
+      return "*flatbuffers.Table";
+  }
+}
+
+static std::string GenTypeGet(const Type &type) {
+  return IsScalar(type.base_type)
+    ? GenTypeBasic(type)
+    : GenTypePointer(type);
+}
+
+static std::string TypeName(const FieldDef &field) {
+  return GenTypeGet(field.value.type);
+}
+
+// Create a struct with a builder and the struct's arguments.
+static void GenStructBuilder(const StructDef &struct_def,
+                             std::string *code_ptr) {
+  BeginBuilderArgs(struct_def, code_ptr);
+  StructBuilderArgs(struct_def, "", code_ptr);
+  EndBuilderArgs(code_ptr);
+
+  StructBuilderBody(struct_def, "", code_ptr);
+  EndBuilderBody(code_ptr);
+}
+
+}  // namespace go
+
+bool GenerateGo(const Parser &parser,
+                const std::string &path,
+                const std::string & /*file_name*/,
+                const GeneratorOptions & /*opts*/) {
+  for (auto it = parser.enums_.vec.begin();
+       it != parser.enums_.vec.end(); ++it) {
+    std::string enumcode;
+    go::GenEnum(**it, &enumcode);
+    if (!go::SaveType(parser, **it, enumcode, path, false))
+      return false;
+  }
+
+  for (auto it = parser.structs_.vec.begin();
+       it != parser.structs_.vec.end(); ++it) {
+    std::string declcode;
+    go::GenStruct(**it, &declcode, parser.root_struct_def);
+    if (!go::SaveType(parser, **it, declcode, path, true))
+      return false;
+  }
+
+  return true;
+}
+
+}  // namespace flatbuffers
+