From 883b1acc1b630844df1d746d575f96a0dd6b3ccd Mon Sep 17 00:00:00 2001
From: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Date: Sat, 20 Mar 2021 14:07:23 -0700
Subject: [PATCH] protoc-c: add no_generate option

Allows suppression of .pb-c.{c,h} file generation on a .proto file
basis.

protobuf-c.proto: Use the new option in itself, because the options are
never used by protobuf-c runtime, only by the protoc-gen-c compiler.

t/test-full.proto: import protobuf-c.proto to test that
protobuf-c.pb-c.h dependency does not get included in test-full.pb-c.h.
---
 Makefile.am                 |  3 ++-
 protobuf-c/protobuf-c.proto |  6 ++++++
 protoc-c/c_file.cc          | 10 +++++++---
 protoc-c/c_generator.cc     |  3 +++
 t/test-full.proto           |  2 ++
 5 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index d8feb0d..1e1e1df 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -164,7 +164,8 @@ noinst_PROGRAMS += \
 
 t_generated_code2_cxx_generate_packed_data_SOURCES = \
 	t/generated-code2/cxx-generate-packed-data.cc \
-	t/test-full.pb.cc
+	t/test-full.pb.cc \
+	protobuf-c/protobuf-c.pb.cc
 $(t_generated_code2_cxx_generate_packed_data_OBJECTS): t/test-full.pb.h
 t_generated_code2_cxx_generate_packed_data_CXXFLAGS = \
 	$(AM_CXXFLAGS) \
diff --git a/protobuf-c/protobuf-c.proto b/protobuf-c/protobuf-c.proto
index 1c54cf8..66de032 100644
--- a/protobuf-c/protobuf-c.proto
+++ b/protobuf-c/protobuf-c.proto
@@ -30,7 +30,13 @@
 syntax = "proto2";
 import "google/protobuf/descriptor.proto";
 
+// We never need to generate protobuf-c.pb-c.{c,h}, the options are used
+// only by protoc-gen-c, never by the protobuf-c runtime itself
+option (pb_c_file).no_generate = true;
+
 message ProtobufCFileOptions {
+    // Suppresses pb-c.{c,h} file output completely.
+    optional bool no_generate = 1 [default = false];
 }
 
 extend google.protobuf.FileOptions {
diff --git a/protoc-c/c_file.cc b/protoc-c/c_file.cc
index f291679..9ea788b 100644
--- a/protoc-c/c_file.cc
+++ b/protoc-c/c_file.cc
@@ -157,9 +157,13 @@ void FileGenerator::GenerateHeader(io::Printer* printer) {
     "protoc_version", SimpleItoa(PROTOBUF_C_VERSION_NUMBER));
 
   for (int i = 0; i < file_->dependency_count(); i++) {
-    printer->Print(
-      "#include \"$dependency$.pb-c.h\"\n",
-      "dependency", StripProto(file_->dependency(i)->name()));
+    const ProtobufCFileOptions opt =
+	    file_->dependency(i)->options().GetExtension(pb_c_file);
+    if (!opt.no_generate()) {
+      printer->Print(
+        "#include \"$dependency$.pb-c.h\"\n",
+	"dependency", StripProto(file_->dependency(i)->name()));
+    }
   }
 
   printer->Print("\n");
diff --git a/protoc-c/c_generator.cc b/protoc-c/c_generator.cc
index e30cf7b..e2fccdf 100644
--- a/protoc-c/c_generator.cc
+++ b/protoc-c/c_generator.cc
@@ -106,6 +106,9 @@ bool CGenerator::Generate(const FileDescriptor* file,
                             const std::string& parameter,
                             OutputDirectory* output_directory,
                             std::string* error) const {
+  if (file->options().GetExtension(pb_c_file).no_generate())
+    return true;
+
   std::vector<std::pair<std::string, std::string> > options;
   ParseOptions(parameter, &options);
 
diff --git a/t/test-full.proto b/t/test-full.proto
index c04fce7..2ebd690 100644
--- a/t/test-full.proto
+++ b/t/test-full.proto
@@ -1,5 +1,7 @@
 package foo;
 
+import "protobuf-c/protobuf-c.proto";
+
 message SubMess {
   required int32 test = 4;