Add support for compiling proto files using gpb

This adds the config option {proto_compiler,gpb} for selecting gpb
as the compiler for protocol buffer files. When gpb is used as
compiler, it reads the gpb_opts config item for options.

ebin/rebar.app

@@ -30,6 +30,7 @@
               rebar_port_compiler,
               rebar_proto_compiler,
               rebar_protobuffs_compiler,
+              rebar_proto_gpb_compiler,
               rebar_qc,
               rebar_rel_utils,
               rebar_reltool,
@@ -70,6 +71,7 @@
                                rebar_abnfc_compiler,
                                rebar_proto_compiler,
                                rebar_protobuffs_compiler,
+                               rebar_proto_gpb_compiler,
                                rebar_neotoma_compiler,
                                rebar_asn1_compiler,
                                rebar_dia_compiler,

rebar.config

@@ -24,6 +24,7 @@
       - (\"lfe_comp\":\"file\"/\"2\")
       - (\"neotoma\":\"file\"/\"2\")
       - (\"protobuffs_compile\":\"scan_file\"/\"2\")
+      - (\"gpb_compile\":\"file\"/\"2\")
       - (\"diameter_codegen\":\"from_dict\"/\"4\")
       - (\"diameter_dict_util\":\"format_error\"/\"1\")
       - (\"diameter_dict_util\":\"parse\"/\"2\"))",

rebar.config.sample

@@ -93,7 +93,11 @@
 {proto_compiler, protobuffs}.
 %% Available compilers for protocol buffer files (*.proto):
 %%   protobuffs  (default)
+%%   gpb
 
+%% Options for the gpb protocol buffer compiler,
+%% if selected by the proto_compiler option
+{gpb_opts, []}.
 
 %% == EUnit ==
 

src/rebar_proto_gpb_compiler.erl

@@ -0,0 +1,119 @@
+%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
+%% ex: ts=4 sw=4 et
+%% -------------------------------------------------------------------
+%%
+%% rebar: Erlang Build Tools
+%%
+%% Copyright (c) 2014 Tomas Abrahamsson (tomas.abrahamsson@gmail.com)
+%%
+%% Permission is hereby granted, free of charge, to any person obtaining a copy
+%% of this software and associated documentation files (the "Software"), to deal
+%% in the Software without restriction, including without limitation the rights
+%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+%% copies of the Software, and to permit persons to whom the Software is
+%% furnished to do so, subject to the following conditions:
+%%
+%% The above copyright notice and this permission notice shall be included in
+%% all copies or substantial portions of the Software.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+%% THE SOFTWARE.
+%% -------------------------------------------------------------------
+-module(rebar_proto_gpb_compiler).
+
+-export([key/0,
+         proto_compile/3,
+         proto_clean/3]).
+
+%% for internal use only
+-export([proto_info/2]).
+
+-include("rebar.hrl").
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
+
+key() ->
+    gpb.
+
+proto_compile(Config, _AppFile, _ProtoFiles) ->
+    %% Check for gpb library -- if it's not present, fail
+    %% since we have.proto files that need building
+    case gpb_is_present() of
+        true ->
+            rebar_base_compiler:run(Config, [],
+                                    "src", ".proto",
+                                    "src", ".erl",
+                                    fun compile_gpb/3,
+                                    [{check_last_mod, true}]);
+        false ->
+            ?ERROR("The gpb library is not present in code path!\n", []),
+            ?FAIL
+    end.
+
+proto_clean(Config, _AppFile, ProtoFiles) ->
+    GpbOpts = gpb_opts(Config),
+    MPrefix = proplists:get_value(module_name_prefix, GpbOpts, ""),
+    MSuffix = proplists:get_value(module_name_suffix, GpbOpts, ""),
+    rebar_file_utils:delete_each(
+      [beam_relpath(MPrefix, F, MSuffix) || F <- ProtoFiles]
+      ++ [erl_relpath(MPrefix, F, MSuffix) || F <- ProtoFiles]
+      ++ [hrl_relpath(MPrefix, F, MSuffix) || F <- ProtoFiles]),
+    ok.
+
+%% ===================================================================
+%% Internal functions
+%% ===================================================================
+
+proto_info(help, compile) ->
+    ?CONSOLE(
+       "  gpb_opts is passed as options to gpb_compile:file/2.~n"
+       "  erl_opts is used when compiling the generated erlang files,~n"
+       "    so you might want to add an include path to gpb here,~n"
+       "    for gpb.hrl, or else use the include_as_lib gpb_opts option,~n"
+       "    or the defs_as_proplists gpb_opts option.~n",
+       []);
+proto_info(help, clean) ->
+    ?CONSOLE("", []).
+
+gpb_opts(Config) ->
+    rebar_config:get_local(Config, gpb_opts, []).
+
+gpb_is_present() ->
+    code:which(gpb) =/= non_existing.
+
+compile_gpb(Source, _Target, Config) ->
+    SourceFullPath = filename:absname(Source),
+    DefaultDestOpts = [{o_erl, "src"}, {o_hrl, "include"}],
+    SelfIncludeOpt = [{i,filename:dirname(SourceFullPath)}],
+    GpbOpts = gpb_opts(Config) ++ DefaultDestOpts ++ SelfIncludeOpt,
+    ok = filelib:ensure_dir(filename:join("ebin", "dummy")),
+    ok = filelib:ensure_dir(filename:join("include", "dummy")),
+    ?CONSOLE("Compiling ~s\n", [Source]),
+    case gpb_compile:file(SourceFullPath, GpbOpts) of
+        ok ->
+            ok;
+        {error, _Reason} ->
+            ?ERROR("Failed to compile ~s~n", [Source]),
+            ?FAIL
+    end.
+
+beam_relpath(Prefix, Proto, Suffix) ->
+    proto_filename_to_relpath("ebin", Prefix, Proto, Suffix, ".beam").
+
+erl_relpath(Prefix, Proto, Suffix) ->
+    proto_filename_to_relpath("src", Prefix, Proto, Suffix, ".erl").
+
+hrl_relpath(Prefix, Proto, Suffix) ->
+    proto_filename_to_relpath("include", Prefix, Proto, Suffix, ".hrl").
+
+proto_filename_to_relpath(Dir, Prefix, Proto, Suffix, NewExt) ->
+    BaseNoExt = filename:basename(Proto, ".proto"),
+    filename:join([Dir, Prefix ++ BaseNoExt ++ Suffix ++ NewExt]).
+