Merge pull request #3843 from Lakedaemon/refactoring

Transition 1 (nice diffs) Go, C++ and General generators with class

CMakeLists.txt

@@ -17,6 +17,7 @@ if(NOT FLATBUFFERS_BUILD_FLATC AND FLATBUFFERS_BUILD_TESTS)
 endif()
 
 set(FlatBuffers_Library_SRCS
+  include/flatbuffers/code_generators.h
   include/flatbuffers/flatbuffers.h
   include/flatbuffers/hash.h
   include/flatbuffers/idl.h

include/flatbuffers/code_generators.h

@@ -0,0 +1,39 @@
+/*
+ * 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.
+ */
+
+#ifndef FLATBUFFERS_CODE_GENERATORS_H_
+#define FLATBUFFERS_CODE_GENERATORS_H_
+
+namespace flatbuffers {
+
+class BaseGenerator {
+ public:
+  BaseGenerator(const Parser &parser, const std::string &path,
+                const std::string &file_name)
+      : parser_(parser), path_(path), file_name_(file_name){};
+  virtual bool generate() = 0;
+
+ protected:
+  virtual ~BaseGenerator(){};
+
+  const Parser &parser_;
+  const std::string &path_;
+  const std::string &file_name_;
+};
+
+}  // namespace flatbuffers
+
+#endif  // FLATBUFFERS_CODE_GENERATORS_H_

src/idl_gen_cpp.cpp

@@ -19,6 +19,7 @@
 #include "flatbuffers/flatbuffers.h"
 #include "flatbuffers/idl.h"
 #include "flatbuffers/util.h"
+#include "flatbuffers/code_generators.h"
 
 namespace flatbuffers {
 namespace cpp {
@@ -714,197 +715,205 @@ struct IsAlnum {
   }
 };
 
-// Iterate through all definitions we haven't generate code for (enums, structs,
-// and tables) and output them to a single file.
-std::string GenerateCPP(const Parser &parser,
-                        const std::string &file_name) {
-  // Check if we have any code to generate at all, to avoid an empty header.
-  for (auto it = parser.enums_.vec.begin(); it != parser.enums_.vec.end();
-       ++it) {
-    if (!(*it)->generated) goto generate_code;
-  }
-  for (auto it = parser.structs_.vec.begin(); it != parser.structs_.vec.end();
-       ++it) {
-    if (!(*it)->generated) goto generate_code;
-  }
-  // No code to generate, exit:
-  return std::string();
-
-  generate_code:
-
-  using namespace cpp;
-
-  std::string code;
-  code = "// automatically generated by the FlatBuffers compiler,"
-         " do not modify\n\n";
-
-  // Generate include guard.
-  std::string include_guard_ident = file_name;
-  // Remove any non-alpha-numeric characters that may appear in a filename.
-  include_guard_ident.erase(
-    std::remove_if(include_guard_ident.begin(),
-                   include_guard_ident.end(),
-                   IsAlnum()),
-    include_guard_ident.end());
-  std::string include_guard = "FLATBUFFERS_GENERATED_" + include_guard_ident;
-  include_guard += "_";
-  // For further uniqueness, also add the namespace.
-  auto name_space = parser.namespaces_.back();
-  for (auto it = name_space->components.begin();
-           it != name_space->components.end(); ++it) {
-    include_guard += *it + "_";
-  }
-  include_guard += "H_";
-  std::transform(include_guard.begin(), include_guard.end(),
-                 include_guard.begin(), ::toupper);
-  code += "#ifndef " + include_guard + "\n";
-  code += "#define " + include_guard + "\n\n";
-
-  code += "#include \"flatbuffers/flatbuffers.h\"\n\n";
-
-  if (parser.opts.include_dependence_headers) {
-    int num_includes = 0;
-    for (auto it = parser.included_files_.begin();
-         it != parser.included_files_.end(); ++it) {
-      auto basename = flatbuffers::StripPath(
-                        flatbuffers::StripExtension(it->first));
-      if (basename != file_name) {
-        code += "#include \"" + basename + "_generated.h\"\n";
-        num_includes++;
-      }
-    }
-    if (num_includes) code += "\n";
-  }
-
-  assert(!code_generator_cur_name_space);
-
-  // Generate forward declarations for all structs/tables, since they may
-  // have circular references.
-  for (auto it = parser.structs_.vec.begin();
-       it != parser.structs_.vec.end(); ++it) {
-    auto &struct_def = **it;
-    if (!struct_def.generated) {
-      CheckNameSpace(struct_def, &code);
-      code += "struct " + struct_def.name + ";\n\n";
-    }
-  }
-
-  // Generate code for all the enum declarations.
-  for (auto it = parser.enums_.vec.begin();
-       it != parser.enums_.vec.end(); ++it) {
-    auto &enum_def = **it;
-    if (!enum_def.generated) {
-      CheckNameSpace(**it, &code);
-      GenEnum(parser, **it, &code);
-    }
-  }
-
-  // Generate code for all structs, then all tables.
-  for (auto it = parser.structs_.vec.begin();
-       it != parser.structs_.vec.end(); ++it) {
-    auto &struct_def = **it;
-    if (struct_def.fixed && !struct_def.generated) {
-      CheckNameSpace(struct_def, &code);
-      GenStruct(parser, struct_def, &code);
-    }
-  }
-  for (auto it = parser.structs_.vec.begin();
-       it != parser.structs_.vec.end(); ++it) {
-    auto &struct_def = **it;
-    if (!struct_def.fixed && !struct_def.generated) {
-      CheckNameSpace(struct_def, &code);
-      GenTable(parser, struct_def, &code);
-    }
-  }
-
-  // Generate code for union verifiers.
-  for (auto it = parser.enums_.vec.begin();
-       it != parser.enums_.vec.end(); ++it) {
-    auto &enum_def = **it;
-    if (enum_def.is_union && !enum_def.generated) {
-      CheckNameSpace(enum_def, &code);
-      GenEnumPost(parser, enum_def, &code);
-    }
-  }
-
-  // Generate convenient global helper functions:
-  if (parser.root_struct_def_) {
-    CheckNameSpace(*parser.root_struct_def_, &code);
-    auto &name = parser.root_struct_def_->name;
-    std::string qualified_name =
-        parser.namespaces_.back()->GetFullyQualifiedName(name);
-    std::string cpp_qualified_name = TranslateNameSpace(qualified_name);
-
-    // The root datatype accessor:
-    code += "inline const " + cpp_qualified_name + " *Get";
-    code += name;
-    code += "(const void *buf) { return flatbuffers::GetRoot<";
-    code += cpp_qualified_name + ">(buf); }\n\n";
-    if (parser.opts.mutable_buffer) {
-      code += "inline " + name + " *GetMutable";
-      code += name;
-      code += "(void *buf) { return flatbuffers::GetMutableRoot<";
-      code += name + ">(buf); }\n\n";
-    }
-
-    // The root verifier:
-    code += "inline bool Verify";
-    code += name;
-    code += "Buffer(flatbuffers::Verifier &verifier) { "
-            "return verifier.VerifyBuffer<";
-    code += cpp_qualified_name + ">(); }\n\n";
-
-    if (parser.file_identifier_.length()) {
-      // Return the identifier
-      code += "inline const char *" + name;
-      code += "Identifier() { return \"" + parser.file_identifier_;
-      code += "\"; }\n\n";
-
-      // Check if a buffer has the identifier.
-      code += "inline bool " + name;
-      code += "BufferHasIdentifier(const void *buf) { return flatbuffers::";
-      code += "BufferHasIdentifier(buf, ";
-      code += name + "Identifier()); }\n\n";
-    }
-
-    if (parser.file_extension_.length()) {
-      // Return the extension
-      code += "inline const char *" + name;
-      code += "Extension() { return \"" + parser.file_extension_;
-      code += "\"; }\n\n";
-    }
-
-    // Finish a buffer with a given root object:
-    code += "inline void Finish" + name;
-    code += "Buffer(flatbuffers::FlatBufferBuilder &fbb, flatbuffers::Offset<";
-    code += cpp_qualified_name + "> root) { fbb.Finish(root";
-    if (parser.file_identifier_.length())
-      code += ", " + name + "Identifier()";
-    code += "); }\n\n";
-  }
-
-  assert(code_generator_cur_name_space);
-  CloseNestedNameSpaces(code_generator_cur_name_space, &code);
-
-  code_generator_cur_name_space = nullptr;
-
-  // Close the include guard.
-  code += "\n#endif  // " + include_guard + "\n";
-
-  return code;
-}
-
 static std::string GeneratedFileName(const std::string &path,
                                      const std::string &file_name) {
   return path + file_name + "_generated.h";
 }
 
-bool GenerateCPP(const Parser &parser,
+namespace cpp {
-                 const std::string &path,
+class CppGenerator : public BaseGenerator {
+ public:
+  CppGenerator(const Parser &parser, const std::string &path,
+               const std::string &file_name)
+      : BaseGenerator(parser, path, file_name){};
+  // Iterate through all definitions we haven't generate code for (enums,
+  // structs,
+  // and tables) and output them to a single file.
+  bool generate() {
+    // Check if we have any code to generate at all, to avoid an empty header.
+    for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
+         ++it) {
+      if (!(*it)->generated) goto generate_code;
+    }
+    for (auto it = parser_.structs_.vec.begin(); it != parser_.structs_.vec.end();
+         ++it) {
+      if (!(*it)->generated) goto generate_code;
+    }
+    // No code to generate, exit:
+    return true;
+
+  generate_code:
+
+    using namespace cpp;
+
+    std::string code;
+    code =
+        "// automatically generated by the FlatBuffers compiler,"
+        " do not modify\n\n";
+
+    // Generate include guard.
+    std::string include_guard_ident = file_name_;
+    // Remove any non-alpha-numeric characters that may appear in a filename.
+    include_guard_ident.erase(
+        std::remove_if(include_guard_ident.begin(), include_guard_ident.end(),
+                       IsAlnum()),
+        include_guard_ident.end());
+    std::string include_guard = "FLATBUFFERS_GENERATED_" + include_guard_ident;
+    include_guard += "_";
+    // For further uniqueness, also add the namespace.
+    auto name_space = parser_.namespaces_.back();
+    for (auto it = name_space->components.begin();
+         it != name_space->components.end(); ++it) {
+      include_guard += *it + "_";
+    }
+    include_guard += "H_";
+    std::transform(include_guard.begin(), include_guard.end(),
+                   include_guard.begin(), ::toupper);
+    code += "#ifndef " + include_guard + "\n";
+    code += "#define " + include_guard + "\n\n";
+
+    code += "#include \"flatbuffers/flatbuffers.h\"\n\n";
+
+    if (parser_.opts.include_dependence_headers) {
+      int num_includes = 0;
+      for (auto it = parser_.included_files_.begin();
+           it != parser_.included_files_.end(); ++it) {
+        auto basename =
+            flatbuffers::StripPath(flatbuffers::StripExtension(it->first));
+        if (basename != file_name_) {
+          code += "#include \"" + basename + "_generated.h\"\n";
+          num_includes++;
+        }
+      }
+      if (num_includes) code += "\n";
+    }
+
+    assert(!code_generator_cur_name_space);
+
+    // Generate forward declarations for all structs/tables, since they may
+    // have circular references.
+    for (auto it = parser_.structs_.vec.begin(); it != parser_.structs_.vec.end();
+         ++it) {
+      auto &struct_def = **it;
+      if (!struct_def.generated) {
+        CheckNameSpace(struct_def, &code);
+        code += "struct " + struct_def.name + ";\n\n";
+      }
+    }
+
+    // Generate code for all the enum declarations.
+    for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
+         ++it) {
+      auto &enum_def = **it;
+      if (!enum_def.generated) {
+        CheckNameSpace(**it, &code);
+        GenEnum(parser_, **it, &code);
+      }
+    }
+
+    // Generate code for all structs, then all tables.
+    for (auto it = parser_.structs_.vec.begin(); it != parser_.structs_.vec.end();
+         ++it) {
+      auto &struct_def = **it;
+      if (struct_def.fixed && !struct_def.generated) {
+        CheckNameSpace(struct_def, &code);
+        GenStruct(parser_, struct_def, &code);
+      }
+    }
+    for (auto it = parser_.structs_.vec.begin(); it != parser_.structs_.vec.end();
+         ++it) {
+      auto &struct_def = **it;
+      if (!struct_def.fixed && !struct_def.generated) {
+        CheckNameSpace(struct_def, &code);
+        GenTable(parser_, struct_def, &code);
+      }
+    }
+
+    // Generate code for union verifiers.
+    for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
+         ++it) {
+      auto &enum_def = **it;
+      if (enum_def.is_union && !enum_def.generated) {
+        CheckNameSpace(enum_def, &code);
+        GenEnumPost(parser_, enum_def, &code);
+      }
+    }
+
+    // Generate convenient global helper functions:
+    if (parser_.root_struct_def_) {
+      CheckNameSpace(*parser_.root_struct_def_, &code);
+      auto &name = parser_.root_struct_def_->name;
+      std::string qualified_name =
+          parser_.namespaces_.back()->GetFullyQualifiedName(name);
+      std::string cpp_qualified_name = TranslateNameSpace(qualified_name);
+
+      // The root datatype accessor:
+      code += "inline const " + cpp_qualified_name + " *Get";
+      code += name;
+      code += "(const void *buf) { return flatbuffers::GetRoot<";
+      code += cpp_qualified_name + ">(buf); }\n\n";
+      if (parser_.opts.mutable_buffer) {
+        code += "inline " + name + " *GetMutable";
+        code += name;
+        code += "(void *buf) { return flatbuffers::GetMutableRoot<";
+        code += name + ">(buf); }\n\n";
+      }
+
+      // The root verifier:
+      code += "inline bool Verify";
+      code += name;
+      code +=
+          "Buffer(flatbuffers::Verifier &verifier) { "
+          "return verifier.VerifyBuffer<";
+      code += cpp_qualified_name + ">(); }\n\n";
+
+      if (parser_.file_identifier_.length()) {
+        // Return the identifier
+        code += "inline const char *" + name;
+        code += "Identifier() { return \"" + parser_.file_identifier_;
+        code += "\"; }\n\n";
+
+        // Check if a buffer has the identifier.
+        code += "inline bool " + name;
+        code += "BufferHasIdentifier(const void *buf) { return flatbuffers::";
+        code += "BufferHasIdentifier(buf, ";
+        code += name + "Identifier()); }\n\n";
+      }
+
+      if (parser_.file_extension_.length()) {
+        // Return the extension
+        code += "inline const char *" + name;
+        code += "Extension() { return \"" + parser_.file_extension_;
+        code += "\"; }\n\n";
+      }
+
+      // Finish a buffer with a given root object:
+      code += "inline void Finish" + name;
+      code +=
+          "Buffer(flatbuffers::FlatBufferBuilder &fbb, flatbuffers::Offset<";
+      code += cpp_qualified_name + "> root) { fbb.Finish(root";
+      if (parser_.file_identifier_.length())
+        code += ", " + name + "Identifier()";
+      code += "); }\n\n";
+    }
+
+    assert(code_generator_cur_name_space);
+    CloseNestedNameSpaces(code_generator_cur_name_space, &code);
+
+    code_generator_cur_name_space = nullptr;
+
+    // Close the include guard.
+    code += "\n#endif  // " + include_guard + "\n";
+
+    return SaveFile(GeneratedFileName(path_, file_name_).c_str(), code, false);
+  }
+};
+}  // namespace cpp
+
+bool GenerateCPP(const Parser &parser, const std::string &path,
                  const std::string &file_name) {
-    auto code = GenerateCPP(parser, file_name);
+  cpp::CppGenerator generator(parser, path, file_name);
-    return !code.length() ||
+  return generator.generate();
-           SaveFile(GeneratedFileName(path, file_name).c_str(), code, false);
 }
 
 std::string CPPMakeRule(const Parser &parser,

src/idl_gen_general.cpp

@@ -19,6 +19,7 @@
 #include "flatbuffers/flatbuffers.h"
 #include "flatbuffers/idl.h"
 #include "flatbuffers/util.h"
+#include "flatbuffers/code_generators.h"
 #include <algorithm>
 
 namespace flatbuffers {
@@ -1148,44 +1149,56 @@ static bool SaveClass(const LanguageParameters &lang, const Parser &parser,
   return SaveFile(filename.c_str(), code, false);
 }
 
-bool GenerateGeneral(const Parser &parser,
+namespace general {
-                     const std::string &path,
+class GeneralGenerator : public BaseGenerator {
-                     const std::string & file_name) {
+ public:
+  GeneralGenerator(const Parser &parser, const std::string &path,
+                   const std::string &file_name)
+      : BaseGenerator(parser, path, file_name){};
+  bool generate() {
+    assert(parser_.opts.lang <= IDLOptions::kMAX);
+    auto lang = language_parameters[parser_.opts.lang];
+    std::string one_file_code;
 
-  assert(parser.opts.lang <= IDLOptions::kMAX);
+    for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
-  auto lang = language_parameters[parser.opts.lang];
+         ++it) {
-  std::string one_file_code;
+      std::string enumcode;
+      GenEnum(lang, parser_, **it, &enumcode);
+      if (parser_.opts.one_file) {
+        one_file_code += enumcode;
+      } else {
+        if (!SaveClass(lang, parser_, (**it).name, enumcode, path_, false,
+                       false))
+          return false;
+      }
+    }
 
-  for (auto it = parser.enums_.vec.begin();
+    for (auto it = parser_.structs_.vec.begin();
-       it != parser.enums_.vec.end(); ++it) {
+         it != parser_.structs_.vec.end(); ++it) {
-    std::string enumcode;
+      std::string declcode;
-    GenEnum(lang, parser, **it, &enumcode);
+      GenStruct(lang, parser_, **it, &declcode);
-    if (parser.opts.one_file) {
+      if (parser_.opts.one_file) {
-      one_file_code += enumcode;
+        one_file_code += declcode;
+      } else {
+        if (!SaveClass(lang, parser_, (**it).name, declcode, path_, true,
+                       false))
+          return false;
+      }
     }
-    else {
+
-      if (!SaveClass(lang, parser, (**it).name, enumcode, path, false, false))
+    if (parser_.opts.one_file) {
-        return false;
+      return SaveClass(lang, parser_, file_name_, one_file_code, path_, true,
+                       true);
     }
+    return true;
   }
+};
+}  // namespace general
 
-  for (auto it = parser.structs_.vec.begin();
+bool GenerateGeneral(const Parser &parser, const std::string &path,
-       it != parser.structs_.vec.end(); ++it) {
+                     const std::string &file_name) {
-    std::string declcode;
+  general::GeneralGenerator generator(parser, path, file_name);
-    GenStruct(lang, parser, **it, &declcode);
+  return generator.generate();
-    if (parser.opts.one_file) {
-      one_file_code += declcode;
-    }
-    else {
-      if (!SaveClass(lang, parser, (**it).name, declcode, path, true, false))
-        return false;
-    }
-  }
-
-  if (parser.opts.one_file) {
-    return SaveClass(lang, parser, file_name, one_file_code,path, true, true);
-  }
-  return true;
 }
 
 static std::string ClassFileName(const LanguageParameters &lang,

src/idl_gen_go.cpp

@@ -21,6 +21,7 @@
 #include "flatbuffers/flatbuffers.h"
 #include "flatbuffers/idl.h"
 #include "flatbuffers/util.h"
+#include "flatbuffers/code_generators.h"
 
 #ifdef _WIN32
 #include <direct.h>
@@ -660,28 +661,35 @@ static void GenStructBuilder(const StructDef &struct_def,
   EndBuilderBody(code_ptr);
 }
 
+class GoGenerator : public BaseGenerator {
+ public:
+  GoGenerator(const Parser &parser, const std::string &path,
+              const std::string &file_name)
+      : BaseGenerator(parser, path, file_name){};
+  bool generate() {
+    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 go
 
-bool GenerateGo(const Parser &parser,
+bool GenerateGo(const Parser &parser, const std::string &path,
-                const std::string &path,
+                const std::string &file_name) {
-                const std::string & /*file_name*/) {
+  go::GoGenerator generator(parser, path, file_name);
-  for (auto it = parser.enums_.vec.begin();
+  return generator.generate();
-       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

src/idl_gen_js.cpp

@@ -19,6 +19,7 @@
 #include "flatbuffers/flatbuffers.h"
 #include "flatbuffers/idl.h"
 #include "flatbuffers/util.h"
+#include "flatbuffers/code_generators.h"
 
 namespace flatbuffers {
 namespace js {
@@ -661,60 +662,76 @@ static void GenStruct(const Parser &parser, StructDef &struct_def,
 
 }  // namespace js
 
-// Iterate through all definitions we haven't generate code for (enums, structs,
-// and tables) and output them to a single file.
-std::string GenerateJS(const Parser &parser) {
-  using namespace js;
-
-  // Generate code for all the enum declarations.
-  std::string enum_code, exports_code;
-  for (auto it = parser.enums_.vec.begin();
-       it != parser.enums_.vec.end(); ++it) {
-    GenEnum(**it, &enum_code, &exports_code);
-  }
-
-  // Generate code for all structs, then all tables.
-  std::string decl_code;
-  for (auto it = parser.structs_.vec.begin();
-       it != parser.structs_.vec.end(); ++it) {
-    GenStruct(parser, **it, &decl_code, &exports_code);
-  }
-
-  // Only output file-level code if there were any declarations.
-  if (enum_code.length() || decl_code.length()) {
-    std::string code;
-    code = "// automatically generated by the FlatBuffers compiler,"
-           " do not modify\n\n";
-
-    // Generate code for all the namespace declarations.
-    GenNamespaces(parser, &code, &exports_code);
-
-    // Output the main declaration code from above.
-    code += enum_code;
-    code += decl_code;
-
-    if (!exports_code.empty() && !parser.opts.skip_js_exports) {
-      code += "// Exports for Node.js and RequireJS\n";
-      code += exports_code;
-    }
-
-    return code;
-  }
-
-  return std::string();
-}
-
 static std::string GeneratedFileName(const std::string &path,
                                      const std::string &file_name) {
   return path + file_name + "_generated.js";
 }
 
-bool GenerateJS(const Parser &parser,
+namespace js {
-                const std::string &path,
+// Iterate through all definitions we haven't generate code for (enums, structs,
-                const std::string &file_name) {
+// and tables) and output them to a single file.
-    auto code = GenerateJS(parser);
+class JsGenerator : public BaseGenerator {
+ public:
+  JsGenerator(const Parser &parser, const std::string &path,
+              const std::string &file_name)
+      : BaseGenerator(parser, path, file_name){};
+  // Iterate through all definitions we haven't generate code for (enums,
+  // structs, and tables) and output them to a single file.
+  bool generate() {
+    std::string enum_code, struct_code, exports_code, code;
+    generateEnums(&enum_code, &exports_code);
+    generateStructs(&struct_code, &exports_code);
+
+    // Only output file-level code if there were any declarations.
+    if (enum_code.length() || struct_code.length()) {
+      code +=
+          "// automatically generated by the FlatBuffers compiler, do not "
+          "modify\n\n";
+
+      // Generate code for all the namespace declarations.
+      GenNamespaces(parser_, &code, &exports_code);
+
+      // Output the main declaration code from above.
+      code += enum_code;
+      code += struct_code;
+
+      if (!exports_code.empty() && !parser_.opts.skip_js_exports) {
+        code += "// Exports for Node.js and RequireJS\n";
+        code += exports_code;
+      }
+    }
+
     return !code.length() ||
-           SaveFile(GeneratedFileName(path, file_name).c_str(), code, false);
+           SaveFile(GeneratedFileName(path_, file_name_).c_str(), code, false);
+  }
+
+ private:
+  // Generate code for all enums.
+  void generateEnums(std::string *enum_code_ptr,
+                     std::string *exports_code_ptr) {
+    for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
+         ++it) {
+      auto &enum_def = **it;
+      GenEnum(enum_def, enum_code_ptr, exports_code_ptr);
+    }
+  }
+
+  // Generate code for all structs.
+  void generateStructs(std::string *decl_code_ptr,
+                       std::string *exports_code_ptr) {
+    for (auto it = parser_.structs_.vec.begin();
+         it != parser_.structs_.vec.end(); ++it) {
+      auto &struct_def = **it;
+      GenStruct(parser_, struct_def, decl_code_ptr, exports_code_ptr);
+    }
+  }
+};
+}  // namespace js
+
+bool GenerateJS(const Parser &parser, const std::string &path,
+                const std::string &file_name) {
+  js::JsGenerator generator(parser, path, file_name);
+  return generator.generate();
 }
 
 std::string JSMakeRule(const Parser &parser,

src/idl_gen_php.cpp

@@ -21,6 +21,7 @@
 #include "flatbuffers/flatbuffers.h"
 #include "flatbuffers/idl.h"
 #include "flatbuffers/util.h"
+#include "flatbuffers/code_generators.h"
 
 namespace flatbuffers {
 namespace php {
@@ -974,29 +975,47 @@ namespace php {
       code += Indent + "}\n";
     }
 
-}  // namespace php
+    class PhpGenerator : public BaseGenerator {
+     public:
+      PhpGenerator(const Parser &parser, const std::string &path,
+                   const std::string &file_name)
+          : BaseGenerator(parser, path, file_name){};
+      bool generate() {
+        if (!generateEnums()) return false;
+        if (!generateStructs()) return false;
+        return true;
+      }
 
-  bool GeneratePhp(const Parser &parser,
+     private:
-    const std::string &path,
+      bool generateEnums() {
-    const std::string & /*file_name*/) {
+        for (auto it = parser_.enums_.vec.begin();
-    for (auto it = parser.enums_.vec.begin();
+             it != parser_.enums_.vec.end(); ++it) {
-    it != parser.enums_.vec.end(); ++it) {
+          auto &enum_def = **it;
-      std::string enumcode;
+          std::string enumcode;
-      php::GenEnum(**it, &enumcode);
+          GenEnum(enum_def, &enumcode);
+          if (!SaveType(parser_, enum_def, enumcode, path_, false))
+            return false;
+        }
+        return true;
+      }
 
-      if (!php::SaveType(parser, **it, enumcode, path, false))
+      bool generateStructs() {
-        return false;
+        for (auto it = parser_.structs_.vec.begin();
+             it != parser_.structs_.vec.end(); ++it) {
+          auto &struct_def = **it;
+          std::string declcode;
+          GenStruct(parser_, struct_def, &declcode);
+          if (!SaveType(parser_, struct_def, declcode, path_, true))
+            return false;
+        }
+        return true;
+      }
+    };
+    }  // namespace php
+
+    bool GeneratePhp(const Parser &parser, const std::string &path,
+                     const std::string &file_name) {
+      php::PhpGenerator generator(parser, path, file_name);
+      return generator.generate();
     }
-
+    }  // namespace flatbuffers
-    for (auto it = parser.structs_.vec.begin();
-    it != parser.structs_.vec.end(); ++it) {
-      std::string declcode;
-      php::GenStruct(parser, **it, &declcode);
-
-      if (!php::SaveType(parser, **it, declcode, path, true))
-        return false;
-    }
-
-    return true;
-}
-}  // namespace flatbuffers

src/idl_gen_python.cpp

@@ -21,6 +21,7 @@
 #include "flatbuffers/flatbuffers.h"
 #include "flatbuffers/idl.h"
 #include "flatbuffers/util.h"
+#include "flatbuffers/code_generators.h"
 
 namespace flatbuffers {
 namespace python {
@@ -634,28 +635,47 @@ static void GenStructBuilder(const StructDef &struct_def,
   EndBuilderBody(code_ptr);
 }
 
+class PythonGenerator : public BaseGenerator {
+ public:
+  PythonGenerator(const Parser &parser, const std::string &path,
+                  const std::string &file_name)
+      : BaseGenerator(parser, path, file_name){};
+  bool generate() {
+    if (!generateEnums()) return false;
+    if (!generateStructs()) return false;
+    return true;
+  }
+
+ private:
+  bool generateEnums() {
+    for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
+         ++it) {
+      auto &enum_def = **it;
+      std::string enumcode;
+      GenEnum(enum_def, &enumcode);
+      if (!SaveType(parser_, enum_def, enumcode, path_, false)) return false;
+    }
+    return true;
+  }
+
+  bool generateStructs() {
+    for (auto it = parser_.structs_.vec.begin();
+         it != parser_.structs_.vec.end(); ++it) {
+      auto &struct_def = **it;
+      std::string declcode;
+      GenStruct(struct_def, &declcode, parser_.root_struct_def_);
+      if (!SaveType(parser_, struct_def, declcode, path_, true)) return false;
+    }
+    return true;
+  }
+};
+
 }  // namespace python
 
-bool GeneratePython(const Parser &parser,
+bool GeneratePython(const Parser &parser, const std::string &path,
-                    const std::string &path,
+                    const std::string &file_name) {
-                    const std::string & /*file_name*/) {
+  python::PythonGenerator generator(parser, path, file_name);
-  for (auto it = parser.enums_.vec.begin();
+  return generator.generate();
-       it != parser.enums_.vec.end(); ++it) {
-    std::string enumcode;
-    python::GenEnum(**it, &enumcode);
-    if (!python::SaveType(parser, **it, enumcode, path, false))
-      return false;
-  }
-
-  for (auto it = parser.structs_.vec.begin();
-       it != parser.structs_.vec.end(); ++it) {
-    std::string declcode;
-    python::GenStruct(**it, &declcode, parser.root_struct_def_);
-    if (!python::SaveType(parser, **it, declcode, path, true))
-      return false;
-  }
-
-  return true;
 }
 
 }  // namespace flatbuffers