Allow proto-path in the proto_library target

tools/protoc_wrapper/protoc_wrapper.py

Index: tools/protoc_wrapper/protoc_wrapper.py
diff --git a/tools/protoc_wrapper/protoc_wrapper.py b/tools/protoc_wrapper/protoc_wrapper.py
index 8eac88409c676381924f822e3d2fe924e696663a..534b32799756b757cf446b7af7cb20f21e2ed36e 100755
--- a/tools/protoc_wrapper/protoc_wrapper.py
+++ b/tools/protoc_wrapper/protoc_wrapper.py
@@ -74,6 +74,8 @@ def main(argv):
 
   parser.add_argument("--proto-in-dir",
                       help="Base directory with source protos.")
+  parser.add_argument("--proto-path",

[sdefresne, 2016/10/04 11:29:55]

I would make this an argument that can be passed multiple time (ie.
action="append").

parser.add_argument("--proto-path", action="append",
                       help="Base directory with imported protos.")

[Olivier, 2016/10/04 12:44:31]

Done.

+                      help="Base directory with imported protos.")
   parser.add_argument("--cc-out-dir",
                       help="Output directory for standard C++ generator.")
   parser.add_argument("--py-out-dir",
@@ -121,6 +123,9 @@ def main(argv):
     ]
 
   protoc_cmd += ["--proto_path", proto_dir]
+  if options.proto_path:

[sdefresne, 2016/10/04 11:29:55]

If you change the argument to one that accept multiple items, then you need to
change this to a loop (note that the if before the for is there because the
value will be None if the option is not used, it is possible to remove the need
for the if by adding default=[] to the add_argument call):

if options.proto_path:
  for extra_proto_dir in options.proto_path:
    proto_cmd.extend(["--proto_path", os.path.relpath(extra_proto_dir)]

[Olivier, 2016/10/04 12:44:31]

Done.
Kept the + [] instead of extend for file consistency.

+    protoc_cmd += ["--proto_path", os.path.relpath(options.proto_path)]
+
   protoc_cmd += [os.path.join(proto_dir, name) for name in protos]
   ret = subprocess.call(protoc_cmd)
   if ret != 0: