add support for plugins as pre and post hooks

src/rebar_provider.erl

@@ -66,7 +66,17 @@ new(ModuleName, State0) when is_atom(ModuleName) ->
 -spec do(Provider::t(), rebar_state:t()) ->
                 {ok, rebar_state:t()}.
 do(Provider, State) ->
-    (Provider#provider.provider_impl):do(State).
+    {PreHooks, PostHooks} = rebar_state:hooks(State, Provider#provider.name),
+    {ok, State1} = run_hook_plugins(PreHooks, State),
+    {ok, State2} = (Provider#provider.provider_impl):do(State1),
+    run_hook_plugins(PostHooks, State2).
+
+run_hook_plugins(Hooks, State) ->
+    State1 = lists:foldl(fun(Hook, StateAcc) ->
+                                 {ok, StateAcc1} = rebar_provider:do(Hook, StateAcc),
+                                 StateAcc1
+                         end, State, Hooks),
+    {ok, State1}.
 
 %%% @doc get the name of the module that implements the provider
 %%% @param Provider the provider object

src/rebar_prv_shell.erl

@@ -50,7 +50,7 @@ init(State) ->
                                                         deps = ?DEPS,
                                                         example = "rebar shell",
                                                         short_desc = "Run shell with project apps and deps in path.",
-                                                        desc = "",
+                                                        desc = info(),
                                                         opts = []}),
     {ok, State1}.
 
@@ -91,12 +91,8 @@ shell() ->
     %% this call never returns (until user quits shell)
     timer:sleep(infinity).
 
-info(help, shell) ->
-    ?CONSOLE(
-        "Start a shell with project and deps preloaded similar to~n"
-        "'erl -pa ebin -pa deps/*/ebin'.~n",
-        []
-    ).
+info() ->
+    "Start a shell with project and deps preloaded similar to~n'erl -pa ebin -pa deps/*/ebin'.~n".
 
 remove_error_handler(0) ->
     ?WARN("Unable to remove simple error_logger handler~n", []);

src/rebar_prv_tar.erl

@@ -31,6 +31,5 @@ init(State) ->
 
 -spec do(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().
 do(Config) ->
-    RelxConfig = rebar_state:get_local(Config, relx, []),
     relx:main("release tar"),
     {ok, Config}.

src/rebar_prv_version.erl

@@ -27,6 +27,7 @@ init(State) ->
                                                        short_desc = "Print version for rebar and current Erlang.",
                                                        desc = "",
                                                        opts = []}),
+
     {ok, State1}.
 
 -spec do(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().

src/rebar_state.erl

@@ -14,6 +14,7 @@
          binary_deps/1, binary_deps/2,
          src_deps/1, src_deps/2,
 
+         prepend_hook/3, append_hook/3, hooks/2,
          providers/1, providers/2, add_provider/2]).
 
 -include("rebar.hrl").
@@ -39,6 +40,7 @@
                   project_apps = ordsets:new() :: ordsets:ordset(rebar_app_info:t()),
 
                   providers = [],
+                  hooks = [],
                   skip_dirs = new_skip_dirs() :: rebar_dict() }).
 
 -export_type([t/0]).
@@ -160,6 +162,17 @@ create_logic_providers(ProviderModules, State0) ->
                         State1
                 end, State0, ProviderModules).
 
+prepend_hook(State=#state_t{hooks=Hooks}, Target, Hook) ->
+    {PreHooks, PostHooks} = proplists:get_value(Target, Hooks, {[], []}),
+    State#state_t{hooks=[{Target, {[Hook | PreHooks], PostHooks}} | proplists:delete(Target, Hooks)]}.
+
+append_hook(State=#state_t{hooks=Hooks}, Target, Hook) ->
+    {PreHooks, PostHooks} = proplists:get_value(Target, Hooks, {[], []}),
+    State#state_t{hooks=[{Target, {PreHooks, [Hook | PostHooks]}} | proplists:delete(Target, Hooks)]}.
+
+hooks(#state_t{hooks=Hooks}, Target) ->
+    proplists:get_value(Target, Hooks, {[], []}).
+
 %% ===================================================================
 %% Internal functions
 %% ===================================================================