From 961c95b419ca0aa1e1c8ff6520450fe8e3368de5 Mon Sep 17 00:00:00 2001
From: Dave Smith <dizzyd@dizzyd.com>
Date: Mon, 30 Nov 2009 09:57:28 -0700
Subject: [PATCH] Add protobuffs compiler module

---
 ebin/rebar.app                    |   3 +-
 src/rebar_protobuffs_compiler.erl | 132 ++++++++++++++++++++++++++++++
 2 files changed, 134 insertions(+), 1 deletion(-)
 create mode 100644 src/rebar_protobuffs_compiler.erl

diff --git a/ebin/rebar.app b/ebin/rebar.app
index 2127297..e900fbf 100644
--- a/ebin/rebar.app
+++ b/ebin/rebar.app
@@ -17,7 +17,8 @@
          %% Key/value list of base/default configuration used by
          %% rebar_config during initialization
          {default_config, [
-                           {app_modules, [ rebar_erlc_compiler,
+                           {app_modules, [ rebar_protobuffs_compiler,
+                                           rebar_erlc_compiler,
                                            rebar_app_installer ]}
                            ]}
         ]}
diff --git a/src/rebar_protobuffs_compiler.erl b/src/rebar_protobuffs_compiler.erl
new file mode 100644
index 0000000..540df9f
--- /dev/null
+++ b/src/rebar_protobuffs_compiler.erl
@@ -0,0 +1,132 @@
+%% -------------------------------------------------------------------
+%%
+%% rebar: Erlang Build Tools
+%%
+%% Copyright (c) 2009 Dave Smith (dizzyd@dizzyd.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_protobuffs_compiler).
+
+-export([compile/2,
+         clean/2]).
+
+-include("rebar.hrl").
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
+
+compile(_Config, _AppFile) ->
+    case filelib:wildcard("src/*.proto") of
+        [] ->
+            ok;
+        FoundFiles ->
+            %% Check for protobuffs library -- if it's not present, fail since we have
+            %% .proto files that need building
+            case protobuffs_is_present() of
+                true ->
+                    %% Build a list of output files - { Proto, Beam, Hrl }
+                    Targets = [{Proto, beam_file(Proto), hrl_file(Proto)} || Proto <- FoundFiles],
+
+                    %% Compile each proto file
+                    compile_each(Targets);
+                false ->
+                    ?ERROR("Protobuffs library not present in code path!\n", []),
+                    ?FAIL
+            end
+    end.
+
+
+clean(_Config, _AppFile) ->
+    %% Get a list of generated .beam and .hrl files and then delete them
+    Protos = filelib:wildcard("src/*.proto"),
+    Targets = [fq_beam_file(F) || F <- Protos] ++ [fq_hrl_file(F) || F <- Protos],
+    case Targets of
+        [] ->
+            ok;
+        _ ->
+            delete_each(Targets)
+    end.
+
+
+%% ===================================================================
+%% Internal functions
+%% ===================================================================
+
+protobuffs_is_present() ->
+    case code:which(protobuffs_compile) of
+        non_existing ->
+            false;
+        _ ->
+            true
+    end.
+
+
+beam_file(Proto) ->
+    filename:basename(Proto, ".proto") ++ "_pb.beam".
+
+hrl_file(Proto) ->
+    filename:basename(Proto, ".proto") ++ "_pb.hrl".
+
+fq_beam_file(Proto) ->
+    filename:join(["ebin", filename:basename(Proto, ".proto") ++ "_pb.beam"]).
+
+fq_hrl_file(Proto) ->
+    filename:join(["include", filename:basename(Proto, ".proto") ++ "_pb.hrl"]).
+
+needs_compile(Proto, Beam) ->
+    ActualBeam = filename:join(["ebin", filename:basename(Beam)]),
+    filelib:last_modified(ActualBeam) < filelib:last_modified(Proto).
+
+compile_each([]) ->
+    ok;
+compile_each([{Proto, Beam, Hrl} | Rest]) ->
+    case needs_compile(Proto, Beam) of
+        true ->
+            ?CONSOLE("Compiling ~s\n", [Proto]),
+            case protobuffs_compile:scan_file(Proto) of
+                ok ->
+                    %% Compilation worked, but we need to move the .beam and .hrl file
+                    %% into the ebin/ and include/ directories respectively
+                    %% TODO: Protobuffs really needs to be better about this...sigh.
+                    [] = os:cmd(?FMT("mv ~s ebin", [Beam])),
+                    [] = os:cmd(?FMT("mv ~s include", [Hrl])),
+                    ok;
+                Other ->
+                    ?ERROR("Protobuff compile of ~s failed: ~p\n", [Proto, Other]),
+                    ?FAIL
+            end;
+        false ->
+            ok
+    end,
+    compile_each(Rest).
+
+delete_each([]) ->
+    ok;
+delete_each([File | Rest]) ->
+    case file:delete(File) of
+        ok ->
+            ok;
+        {error, enoent} ->
+            ok;
+        {error, Reason} ->
+            ?ERROR("Failed to delete ~s: ~p\n", [File, Reason])
+    end,
+    delete_each(Rest).