protoc-c: add options for function generation

Add options controller helper function generation. Preserve existing
behavior of not generating pack/unpack functions for sub-messages if
option is not explicitly set.

Fixes #240
Fixes #442

protobuf-c/protobuf-c.proto

@@ -37,6 +37,14 @@ option (pb_c_file).no_generate = true;
 message ProtobufCFileOptions {
     // Suppresses pb-c.{c,h} file output completely.
     optional bool no_generate = 1 [default = false];
+
+    // Generate helper pack/unpack functions?
+    // For backwards compatibility, if this field is not explicitly set,
+    // only top-level message pack/unpack functions will be generated
+    optional bool gen_pack_helpers = 2 [default = true];
+
+    // Generate helper init message functions?
+    optional bool gen_init_helpers = 3 [default = true];
 }
 
 extend google.protobuf.FileOptions {
@@ -44,6 +52,11 @@ extend google.protobuf.FileOptions {
 }
 
 message ProtobufCMessageOptions {
+    // Overrides the parent setting only if present
+    optional bool gen_pack_helpers = 1 [default = false];
+
+    // Overrides the parent setting only if present
+    optional bool gen_init_helpers = 2 [default = true];
 }
 
 extend google.protobuf.MessageOptions {

protoc-c/c_file.cc

@@ -191,7 +191,13 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
   }
 
   for (int i = 0; i < file_->message_type_count(); i++) {
-    message_generators_[i]->GenerateHelperFunctionDeclarations(printer, false);
+    const ProtobufCFileOptions opt = file_->options().GetExtension(pb_c_file);
+
+    message_generators_[i]->GenerateHelperFunctionDeclarations(
+						printer,
+						opt.has_gen_pack_helpers(),
+						opt.gen_pack_helpers(),
+						opt.gen_init_helpers());
   }
 
   printer->Print("/* --- per-message closures --- */\n\n");
@@ -265,11 +271,18 @@ void FileGenerator::GenerateSource(io::Printer* printer) {
   }
 #endif
 
+  const ProtobufCFileOptions opt = file_->options().GetExtension(pb_c_file);
+
   for (int i = 0; i < file_->message_type_count(); i++) {
-    message_generators_[i]->GenerateHelperFunctionDefinitions(printer, false);
+    message_generators_[i]->GenerateHelperFunctionDefinitions(
+						printer,
+						opt.has_gen_pack_helpers(),
+						opt.gen_pack_helpers(),
+						opt.gen_init_helpers());
   }
   for (int i = 0; i < file_->message_type_count(); i++) {
-    message_generators_[i]->GenerateMessageDescriptor(printer);
+    message_generators_[i]->GenerateMessageDescriptor(printer,
+						      opt.gen_init_helpers());
   }
   for (int i = 0; i < file_->enum_type_count(); i++) {
     enum_generators_[i]->GenerateEnumDescriptor(printer);

protoc-c/c_message.cc

@@ -252,21 +252,38 @@ GenerateStructDefinition(io::Printer* printer) {
 }
 
 void MessageGenerator::
-GenerateHelperFunctionDeclarations(io::Printer* printer, bool is_submessage)
+GenerateHelperFunctionDeclarations(io::Printer* printer,
+				   bool is_pack_deep,
+				   bool gen_pack,
+				   bool gen_init)
 {
+  const ProtobufCMessageOptions opt =
+	  descriptor_->options().GetExtension(pb_c_msg);
+
+  // Override parent settings, if needed
+  if (opt.has_gen_pack_helpers())
+    gen_pack = opt.gen_pack_helpers();
+  if (opt.has_gen_init_helpers())
+    gen_init = opt.gen_init_helpers();
+
   for (int i = 0; i < descriptor_->nested_type_count(); i++) {
-    nested_generators_[i]->GenerateHelperFunctionDeclarations(printer, true);
+    bool nested_pack = !is_pack_deep ? opt.gen_pack_helpers() : gen_pack;
+    nested_generators_[i]->GenerateHelperFunctionDeclarations(printer, true,
+							      nested_pack,
+							      gen_init);
   }
 
   std::map<std::string, std::string> vars;
   vars["classname"] = FullNameToC(descriptor_->full_name());
   vars["lcclassname"] = FullNameToLower(descriptor_->full_name());
-  printer->Print(vars,
+  if (gen_init) {
+    printer->Print(vars,
 		 "/* $classname$ methods */\n"
 		 "void   $lcclassname$__init\n"
 		 "                     ($classname$         *message);\n"
 		);
-  if (!is_submessage) {
+  }
+  if (gen_pack) {
     printer->Print(vars,
 		 "size_t $lcclassname$__get_packed_size\n"
 		 "                     (const $classname$   *message);\n"
@@ -325,24 +342,41 @@ compare_pfields_by_number (const void *a, const void *b)
 }
 
 void MessageGenerator::
-GenerateHelperFunctionDefinitions(io::Printer* printer, bool is_submessage)
+GenerateHelperFunctionDefinitions(io::Printer* printer,
+				  bool is_pack_deep,
+				  bool gen_pack,
+				  bool gen_init)
 {
+  const ProtobufCMessageOptions opt =
+	  descriptor_->options().GetExtension(pb_c_msg);
+
+  // Override parent settings, if needed
+  if (opt.has_gen_pack_helpers())
+    gen_pack = opt.gen_pack_helpers();
+  if (opt.has_gen_init_helpers())
+    gen_init = opt.gen_init_helpers();
+
   for (int i = 0; i < descriptor_->nested_type_count(); i++) {
-    nested_generators_[i]->GenerateHelperFunctionDefinitions(printer, true);
+    bool nested_pack = !is_pack_deep ? opt.gen_pack_helpers() : gen_pack;
+    nested_generators_[i]->GenerateHelperFunctionDefinitions(printer, true,
+							     nested_pack,
+							     gen_init);
   }
 
   std::map<std::string, std::string> vars;
   vars["classname"] = FullNameToC(descriptor_->full_name());
   vars["lcclassname"] = FullNameToLower(descriptor_->full_name());
   vars["ucclassname"] = FullNameToUpper(descriptor_->full_name());
-  printer->Print(vars,
+  if (gen_init) {
+    printer->Print(vars,
 		 "void   $lcclassname$__init\n"
 		 "                     ($classname$         *message)\n"
 		 "{\n"
 		 "  static const $classname$ init_value = $ucclassname$__INIT;\n"
 		 "  *message = init_value;\n"
 		 "}\n");
-  if (!is_submessage) {
+  }
+  if (gen_pack) {
     printer->Print(vars,
 		 "size_t $lcclassname$__get_packed_size\n"
 		 "                     (const $classname$ *message)\n"
@@ -388,7 +422,7 @@ GenerateHelperFunctionDefinitions(io::Printer* printer, bool is_submessage)
 }
 
 void MessageGenerator::
-GenerateMessageDescriptor(io::Printer* printer) {
+GenerateMessageDescriptor(io::Printer* printer, bool gen_init) {
     std::map<std::string, std::string> vars;
     vars["fullname"] = descriptor_->full_name();
     vars["classname"] = FullNameToC(descriptor_->full_name());
@@ -401,8 +435,14 @@ GenerateMessageDescriptor(io::Printer* printer) {
         descriptor_->file()->options().optimize_for() ==
         FileOptions_OptimizeMode_CODE_SIZE;
 
+    const ProtobufCMessageOptions opt =
+	    descriptor_->options().GetExtension(pb_c_msg);
+    // Override parent settings, if needed
+    if (opt.has_gen_init_helpers())
+      gen_init = opt.gen_init_helpers();
+
     for (int i = 0; i < descriptor_->nested_type_count(); i++) {
-      nested_generators_[i]->GenerateMessageDescriptor(printer);
+      nested_generators_[i]->GenerateMessageDescriptor(printer, gen_init);
     }
 
     for (int i = 0; i < descriptor_->enum_type_count(); i++) {
@@ -568,8 +608,15 @@ GenerateMessageDescriptor(io::Printer* printer) {
   }
   printer->Print(vars,
       "  $n_ranges$,"
-      "  $lcclassname$__number_ranges,\n"
-      "  (ProtobufCMessageInit) $lcclassname$__init,\n"
+      "  $lcclassname$__number_ranges,\n");
+  if (gen_init) {
+    printer->Print(vars,
+      "  (ProtobufCMessageInit) $lcclassname$__init,\n");
+  } else {
+    printer->Print(vars,
+      "  NULL, /* gen_init_helpers = false */\n");
+  }
+  printer->Print(vars,
       "  NULL,NULL,NULL    /* reserved[123] */\n"
       "};\n");
 }

protoc-c/c_message.h

@@ -111,14 +111,20 @@ class MessageGenerator {
   void GenerateStructStaticInitMacro(io::Printer* printer);
 
   // Generate standard helper functions declarations for this message.
-  void GenerateHelperFunctionDeclarations(io::Printer* printer, bool is_submessage);
+  void GenerateHelperFunctionDeclarations(io::Printer* printer,
+					  bool is_pack_deep,
+					  bool gen_pack,
+					  bool gen_init);
 
   // Source file stuff.
 
   // Generate code that initializes the global variable storing the message's
   // descriptor.
-  void GenerateMessageDescriptor(io::Printer* printer);
-  void GenerateHelperFunctionDefinitions(io::Printer* printer, bool is_submessage);
+  void GenerateMessageDescriptor(io::Printer* printer, bool gen_init);
+  void GenerateHelperFunctionDefinitions(io::Printer* printer,
+					 bool is_pack_deep,
+					 bool gen_pack,
+					 bool gen_init);
 
  private:
 

t/generated-code2/test-generated-code2.c

@@ -432,6 +432,39 @@ static void test_required_SubMess (void)
 #undef DO_TEST
 }
 
+static size_t foo__test_mess_optional__get_packed_size
+                     (const Foo__TestMessOptional *message)
+{
+  assert(message->base.descriptor == &foo__test_mess_optional__descriptor);
+  return protobuf_c_message_get_packed_size ((const ProtobufCMessage*)(message));
+}
+static size_t foo__test_mess_optional__pack
+                     (const Foo__TestMessOptional *message,
+                      uint8_t       *out)
+{
+  assert(message->base.descriptor == &foo__test_mess_optional__descriptor);
+  return protobuf_c_message_pack ((const ProtobufCMessage*)message, out);
+}
+static Foo__TestMessOptional *
+       foo__test_mess_optional__unpack
+                     (ProtobufCAllocator  *allocator,
+                      size_t               len,
+                      const uint8_t       *data)
+{
+  return (Foo__TestMessOptional *)
+     protobuf_c_message_unpack (&foo__test_mess_optional__descriptor,
+                                allocator, len, data);
+}
+static void   foo__test_mess_optional__free_unpacked
+                     (Foo__TestMessOptional *message,
+                      ProtobufCAllocator *allocator)
+{
+  if(!message)
+    return;
+  assert(message->base.descriptor == &foo__test_mess_optional__descriptor);
+  protobuf_c_message_free_unpacked ((ProtobufCMessage*)message, allocator);
+}
+
 /* === Optional type fields === */
 static void test_empty_optional (void)
 {

t/test-full.proto

@@ -117,6 +117,8 @@ message TestMessPacked {
 }
 
 message TestMessOptional {
+  option (pb_c_msg).gen_pack_helpers = false;
+  option (pb_c_msg).gen_init_helpers = false;
   optional int32 test_int32 = 1;
   optional sint32 test_sint32 = 2;
   optional sfixed32 test_sfixed32 = 3;