Move runtime import writing into a helper.

File and ImportWriter duplicated the logic, so move it to a helper (on
ImportWriter), and share the impl instead of duplicating it since it
includes some conditional logic around Framework based import support.

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

@@ -209,15 +209,15 @@ FileGenerator::FileGenerator(const FileDescriptor *file, const Options& options)
 FileGenerator::~FileGenerator() {}
 
 void FileGenerator::GenerateHeader(io::Printer *printer) {
-  std::set<string> headers;
+  std::vector<string> headers;
   // Generated files bundled with the library get minimal imports, everything
   // else gets the wrapper so everything is usable.
   if (is_bundled_proto_) {
-    headers.insert("GPBRootObject.h");
-    headers.insert("GPBMessage.h");
-    headers.insert("GPBDescriptor.h");
+    headers.push_back("GPBDescriptor.h");
+    headers.push_back("GPBMessage.h");
+    headers.push_back("GPBRootObject.h");
   } else {
-    headers.insert("GPBProtocolBuffers.h");
+    headers.push_back("GPBProtocolBuffers.h");
   }
   PrintFileRuntimePreamble(printer, headers);
 
@@ -337,8 +337,8 @@ void FileGenerator::GenerateHeader(io::Printer *printer) {
 
 void FileGenerator::GenerateSource(io::Printer *printer) {
   // #import the runtime support.
-  std::set<string> headers;
-  headers.insert("GPBProtocolBuffers_RuntimeSupport.h");
+  std::vector<string> headers;
+  headers.push_back("GPBProtocolBuffers_RuntimeSupport.h");
   PrintFileRuntimePreamble(printer, headers);
 
   // Enums use atomic in the generated code, so add the system import as needed.
@@ -590,48 +590,14 @@ void FileGenerator::GenerateSource(io::Printer *printer) {
 // files. This currently only supports the runtime coming from a framework
 // as defined by the official CocoaPod.
 void FileGenerator::PrintFileRuntimePreamble(
-    io::Printer* printer, const std::set<string>& headers_to_import) const {
+    io::Printer* printer, const std::vector<string>& headers_to_import) const {
   printer->Print(
       "// Generated by the protocol buffer compiler.  DO NOT EDIT!\n"
       "// source: $filename$\n"
       "\n",
       "filename", file_->name());
-
-  const string framework_name(ProtobufLibraryFrameworkName);
-  const string cpp_symbol(ProtobufFrameworkImportSymbol(framework_name));
-
-  printer->Print(
-      "// This CPP symbol can be defined to use imports that match up to the framework\n"
-      "// imports needed when using CocoaPods.\n"
-      "#if !defined($cpp_symbol$)\n"
-      " #define $cpp_symbol$ 0\n"
-      "#endif\n"
-      "\n"
-      "#if $cpp_symbol$\n",
-      "cpp_symbol", cpp_symbol);
-
-
-  for (std::set<string>::const_iterator iter = headers_to_import.begin();
-       iter != headers_to_import.end(); ++iter) {
-    printer->Print(
-        " #import <$framework_name$/$header$>\n",
-        "header", *iter,
-        "framework_name", framework_name);
-  }
-
-  printer->Print(
-      "#else\n");
-
-  for (std::set<string>::const_iterator iter = headers_to_import.begin();
-       iter != headers_to_import.end(); ++iter) {
-    printer->Print(
-        " #import \"$header$\"\n",
-        "header", *iter);
-  }
-
-  printer->Print(
-      "#endif\n"
-      "\n");
+  ImportWriter::PrintRuntimeImports(printer, headers_to_import, true);
+  printer->Print("\n");
 }
 
 }  // namespace objectivec

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

@@ -72,7 +72,7 @@ class FileGenerator {
   const Options options_;
 
   void PrintFileRuntimePreamble(
-      io::Printer* printer, const std::set<string>& headers_to_import) const;
+      io::Printer* printer, const std::vector<string>& headers_to_import) const;
 };
 
 }  // namespace objectivec

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

@@ -1618,30 +1618,7 @@ void ImportWriter::Print(io::Printer* printer) const {
   bool add_blank_line = false;
 
   if (!protobuf_imports_.empty()) {
-    const string framework_name(ProtobufLibraryFrameworkName);
-    const string cpp_symbol(ProtobufFrameworkImportSymbol(framework_name));
-
-    printer->Print(
-        "#if $cpp_symbol$\n",
-        "cpp_symbol", cpp_symbol);
-    for (std::vector<string>::const_iterator iter = protobuf_imports_.begin();
-         iter != protobuf_imports_.end(); ++iter) {
-      printer->Print(
-          " #import <$framework_name$/$header$>\n",
-          "framework_name", framework_name,
-          "header", *iter);
-    }
-    printer->Print(
-        "#else\n");
-    for (std::vector<string>::const_iterator iter = protobuf_imports_.begin();
-         iter != protobuf_imports_.end(); ++iter) {
-      printer->Print(
-          " #import \"$header$\"\n",
-          "header", *iter);
-    }
-    printer->Print(
-        "#endif\n");
-
+    PrintRuntimeImports(printer, protobuf_imports_);
     add_blank_line = true;
   }
 
@@ -1674,6 +1651,44 @@ void ImportWriter::Print(io::Printer* printer) const {
   }
 }
 
+void ImportWriter::PrintRuntimeImports(
+    io::Printer* printer,
+    const std::vector<string>& header_to_import,
+    bool default_cpp_symbol) {
+  const string framework_name(ProtobufLibraryFrameworkName);
+  const string cpp_symbol(ProtobufFrameworkImportSymbol(framework_name));
+
+  if (default_cpp_symbol) {
+    printer->Print(
+        "// This CPP symbol can be defined to use imports that match up to the framework\n"
+        "// imports needed when using CocoaPods.\n"
+        "#if !defined($cpp_symbol$)\n"
+        " #define $cpp_symbol$ 0\n"
+        "#endif\n"
+        "\n",
+        "cpp_symbol", cpp_symbol);
+  }
+
+  printer->Print(
+      "#if $cpp_symbol$\n",
+      "cpp_symbol", cpp_symbol);
+  for (const auto& header : header_to_import) {
+    printer->Print(
+        " #import <$framework_name$/$header$>\n",
+        "framework_name", framework_name,
+        "header", header);
+  }
+  printer->Print(
+      "#else\n");
+  for (const auto& header : header_to_import) {
+    printer->Print(
+        " #import \"$header$\"\n",
+        "header", header);
+  }
+  printer->Print(
+      "#endif\n");
+}
+
 void ImportWriter::ParseFrameworkMappings() {
   need_to_parse_mapping_file_ = false;
   if (named_framework_to_proto_path_mappings_path_.empty()) {

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

@@ -285,6 +285,10 @@ class PROTOC_EXPORT ImportWriter {
   void AddFile(const FileDescriptor* file, const string& header_extension);
   void Print(io::Printer *printer) const;
 
+  static void PrintRuntimeImports(io::Printer *printer,
+                                  const std::vector<string>& header_to_import,
+                                  bool default_cpp_symbol = false);
+
  private:
   class ProtoFrameworkCollector : public LineConsumer {
    public: