Option added to protobuf build for import directories

third_party/protobuf/proto_library.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Compile a protocol buffer.
 #
 # Protobuf parameters:
 #
 #   proto_in_dir (optional)
 #       Specifies the path relative to the current BUILD.gn file where
@@ skipping 45 matching lines @@
 #   generator_plugin_options (optional)
 #       Extra flags passed to the plugin. See cc_generator_options.
 #
 #   deps (optional)
 #       Additional dependencies.
 #
 #   use_protobuf_full (optional)
 #       If adding protobuf library would be required, adds protobuf_full to deps
 #       instead of protobuf_lite.
 #
+#   import_dirs (optional)
+#       A list of extra import directories to be passed to protoc compiler. The
+#       default case is just the source directory.

[xyzzyz, 2017/01/20 18:27:40]

The "source directory" here is pretty ambiguous. I think what you mean (and what
you should put here instead) is proto_in_dir.

[Ramin Halavati, 2017/01/23 14:27:06]

Done.

+#
 # Parameters for compiling the generated code:
 #
 #   component_build_force_source_set (Default=false)
 #       When set true the generated code will be compiled as a source set in
 #       the component build. This does not affect static builds.  If you are
 #       exporting symbols from a component, this is required to prevent those
 #       symbols from being stripped. If you're not using dllexports in
 #       cc_generator_options, it's usually best to leave this false.
 #
 #   defines (optional)
@@ skipping 194 matching lines @@
         rel_cc_out_dir,
       ]
       if (defined(invoker.generator_plugin_options)) {
         args += [
           "--plugin-options",
           invoker.generator_plugin_options,
         ]
       }
     }
 
+    if (defined(invoker.import_dirs)) {

[xyzzyz, 2017/01/20 18:27:40]

The comment and the name of the variable say it's a list of directories, but it
looks like it only supports a single directory.

[Ramin Halavati, 2017/01/23 14:27:06]

If one specifies several directories in import_dirs, rebase_path creates a list
of rebased paths and they are added to arguments with one single --import-dir
switch and protoc_wrapper accepts it this way.

+      args += ["--import-dir"]
+      args += rebase_path(invoker.import_dirs, proto_in_dir)

[xyzzyz, 2017/01/20 18:27:40]

Are you sure you want to rebase it on proto_in_dir? I think importing protos
that are in a subdirectory of proto_in_dir works already.

[Ramin Halavati, 2017/01/23 14:27:06]

I didn't find any documentations on this but it seems that all paths should be
specified relative to the directory of current BUILD.gn file. So I had to rebase
it to root_build_dir. I should note that this new change should also work for
directories which are not subdirectory of protos_in_dir.

+    }
+
     # System protoc is not used so it's necessary to build a chromium one.
     inputs = [
       protoc_path,
     ]
     deps = [
       protoc_label,
     ]
 
     if (generate_with_plugin) {
       inputs += [ plugin_path ]
@@ skipping 78 matching lines @@
       ":$action_name",
     ]
 
     # This will link any libraries in the deps (the use of invoker.deps in the
     # action won't link it).
     if (defined(invoker.deps)) {
       deps += invoker.deps
     }
   }
 }