[ObjC] Move generation options out to their own file.

This will make it easier to pass the option down in the future to the other
parts (message, enum, extension, etc. generators) as needed.

src/file_lists.cmake

@@ -456,6 +456,7 @@ set(libprotoc_hdrs
   ${protobuf_SOURCE_DIR}/src/google/protobuf/compiler/objectivec/objectivec_message_field.h
   ${protobuf_SOURCE_DIR}/src/google/protobuf/compiler/objectivec/objectivec_nsobject_methods.h
   ${protobuf_SOURCE_DIR}/src/google/protobuf/compiler/objectivec/objectivec_oneof.h
+  ${protobuf_SOURCE_DIR}/src/google/protobuf/compiler/objectivec/objectivec_options.h
   ${protobuf_SOURCE_DIR}/src/google/protobuf/compiler/objectivec/objectivec_primitive_field.h
   ${protobuf_SOURCE_DIR}/src/google/protobuf/compiler/php/php_generator.h
   ${protobuf_SOURCE_DIR}/src/google/protobuf/compiler/plugin.h

src/google/protobuf/compiler/objectivec/BUILD.bazel

@@ -35,6 +35,7 @@ cc_library(
         "objectivec_message_field.h",
         "objectivec_nsobject_methods.h",
         "objectivec_oneof.h",
+        "objectivec_options.h",
         "objectivec_primitive_field.h",
     ],
     copts = COPTS,

src/google/protobuf/compiler/objectivec/objectivec_file.h

@@ -35,6 +35,7 @@
 #include <unordered_map>
 #include <unordered_set>
 #include <vector>
+#include "google/protobuf/compiler/objectivec/objectivec_options.h"
 #include "google/protobuf/descriptor.h"
 #include "google/protobuf/io/printer.h"
 
@@ -49,17 +50,6 @@ class MessageGenerator;
 
 class FileGenerator {
  public:
-  struct GenerationOptions {
-    GenerationOptions()
-      // TODO(thomasvl): Eventually flip this default to false for better
-      // interop with Swift if proto usages span modules made from ObjC sources.
-      : headers_use_forward_declarations(true) {}
-    std::string generate_for_named_framework;
-    std::string named_framework_to_proto_path_mappings_path;
-    std::string runtime_import_prefix;
-    bool headers_use_forward_declarations;
-  };
-
   // Wrapper for some common state that is shared between file generations to
   // improve performance when more than one file is generated at a time.
   struct CommonState {

src/google/protobuf/compiler/objectivec/objectivec_generator.cc

@@ -100,7 +100,7 @@ bool ObjectiveCGenerator::GenerateAll(
   // e.g. protoc ... --objc_opt=expected_prefixes=file.txt,generate_for_named_framework=MyFramework
 
   Options validation_options;
-  FileGenerator::GenerationOptions generation_options;
+  GenerationOptions generation_options;
 
   std::vector<std::pair<std::string, std::string> > options;
   ParseGeneratorParameter(parameter, &options);

src/google/protobuf/compiler/objectivec/objectivec_options.h

@@ -0,0 +1,56 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef GOOGLE_PROTOBUF_COMPILER_OBJECTIVEC_OPTIONS_H__
+#define GOOGLE_PROTOBUF_COMPILER_OBJECTIVEC_OPTIONS_H__
+
+#include <string>
+
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace objectivec {
+
+// Generation options, documented within objectivec_generator.cc.
+struct GenerationOptions {
+  std::string generate_for_named_framework;
+  std::string named_framework_to_proto_path_mappings_path;
+  std::string runtime_import_prefix;
+  // TODO(thomasvl): Eventually flip this default to false for better interop
+  // with Swift if proto usages span modules made from ObjC sources.
+  bool headers_use_forward_declarations = true;
+};
+
+}  // namespace objectivec
+}  // namespace compiler
+}  // namespace protobuf
+}  // namespace google
+
+#endif  // GOOGLE_PROTOBUF_COMPILER_OBJECTIVEC_OPTIONS_H__