move app discovery to a dedicated module

2 files changed, 234 insertions, 178 deletions

diff --git a/src/rcl_app_discovery.erl b/src/rcl_app_discovery.erl
new file mode 100644
index 0000000..20df1cf
--- /dev/null
+++ b/src/rcl_app_discovery.erl
@@ -0,0 +1,223 @@
+%% -*- erlang-indent-level: 4; indent-tabs-mode: nil; fill-column: 80 -*-
+%%% Copyright 2012 Erlware, LLC. All Rights Reserved.
+%%%
+%%% This file is provided to you under the Apache License,
+%%% Version 2.0 (the "License"); you may not use this file
+%%% except in compliance with the License.  You may obtain
+%%% a copy of the License at
+%%%
+%%%   http://www.apache.org/licenses/LICENSE-2.0
+%%%
+%%% Unless required by applicable law or agreed to in writing,
+%%% software distributed under the License is distributed on an
+%%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+%%% KIND, either express or implied.  See the License for the
+%%% specific language governing permissions and limitations
+%%% under the License.
+%%%---------------------------------------------------------------------------
+%%% @author Eric Merritt <[email protected]>
+%%% @copyright (C) 2012 Erlware, LLC.
+%%%
+%%% @doc This provider uses the lib_dir setting of the state. It searches the
+%%% Lib Dirs looking for all OTP Applications that are available. When it finds
+%%% those OTP Applications it loads the information about them and adds them to
+%%% the state of available apps. This implements the rcl_provider behaviour.
+-module(rcl_app_discovery).
+
+-export([do/2,
+         format_error/1]).
+
+-include_lib("relcool/include/relcool.hrl").
+
+%%============================================================================
+%% API
+%%============================================================================
+
+%% @doc recursively dig down into the library directories specified in the state
+%% looking for OTP Applications
+-spec do(rcl_state:t(), [filename:name()]) -> {ok, [rcl_app_info:t()]} | relcool:error().
+do(State, LibDirs) ->
+    rcl_log:info(rcl_state:log(State),
+                 fun() ->
+                          ["Resolving OTP Applications from directories:\n",
+                           [[rcl_util:indent(1), LibDir, "\n"] || LibDir <- LibDirs]]
+                 end),
+    resolve_app_metadata(State, LibDirs).
+
+-spec format_error([ErrorDetail::term()]) -> iolist().
+format_error(ErrorDetails)
+  when erlang:is_list(ErrorDetails) ->
+    [[format_detail(ErrorDetail), "\n"] || ErrorDetail <- ErrorDetails].
+
+%%%===================================================================
+%%% Internal Functions
+%%%===================================================================
+resolve_app_metadata(State, LibDirs) ->
+    AppMeta0 = lists:flatten(ec_plists:map(fun(LibDir) ->
+                                               discover_dir([], LibDir)
+                                           end, LibDirs)),
+    AppMeta1 = setup_overrides(State, AppMeta0),
+
+    Errors = [case El of
+                  {error, Ret} -> Ret;
+                  _ -> El
+              end
+              || El <- AppMeta1,
+                 case El of
+                     {error, _} ->
+                         true;
+                     _ ->
+                         false
+                 end],
+
+    case Errors of
+        [] ->
+            AppMeta2 = lists:flatten(AppMeta1),
+            rcl_log:debug(rcl_state:log(State),
+                          fun() ->
+                                  ["Resolved the following OTP Applications from the system: \n",
+                                   [[rcl_app_info:format(1, App), "\n"] || App <- AppMeta2]]
+                          end),
+            {ok, AppMeta2};
+        _ ->
+            ?RCL_ERROR(Errors)
+    end.
+
+app_name({error, _}) ->
+    undefined;
+app_name(AppMeta) ->
+    rcl_app_info:name(AppMeta).
+
+setup_overrides(State, AppMetas0) ->
+    Overrides = rcl_state:overrides(State),
+    AppMetas1 = [AppMeta || AppMeta <- AppMetas0,
+                            not lists:keymember(app_name(AppMeta), 1, Overrides)],
+    [case is_valid_otp_app(filename:join([FileName, "ebin",
+                                         erlang:atom_to_list(AppName) ++ ".app"])) of
+         [] ->
+             {error, {invalid_override, AppName, FileName}};
+         Error = {error, _} ->
+             Error;
+         App ->
+             rcl_app_info:link(App, true)
+     end || {AppName, FileName} <- Overrides] ++ AppMetas1.
+
+
+
+-spec format_detail(ErrorDetail::term()) -> iolist().
+format_detail({error, {invalid_override, AppName, FileName}}) ->
+    io_lib:format("Override {~p, ~p} is not a valid OTP App. Perhaps you forgot to build it?",
+                  [AppName, FileName]);
+format_detail({accessing, File, eaccess}) ->
+    io_lib:format("permission denied accessing file ~s", [File]);
+format_detail({accessing, File, Type}) ->
+    io_lib:format("error (~p) accessing file ~s", [Type, File]);
+format_detail({no_beam_files, EbinDir}) ->
+    io_lib:format("no beam files found in directory ~s", [EbinDir]);
+format_detail({not_a_directory, EbinDir}) ->
+    io_lib:format("~s is not a directory when it should be a directory", [EbinDir]);
+format_detail({unable_to_load_app, AppDir, _}) ->
+    io_lib:format("Unable to load the application metadata from ~s", [AppDir]);
+format_detail({invalid_app_file, File}) ->
+    io_lib:format("Application metadata file exists but is malformed: ~s",
+                  [File]);
+format_detail({unversioned_app, AppDir, _AppName}) ->
+    io_lib:format("Application metadata exists but version is not available: ~s",
+                  [AppDir]);
+format_detail({app_info_error, {Module, Detail}}) ->
+    Module:format_error(Detail).
+
+-spec discover_dir([file:name()],
+                   file:name()) ->
+                          [rcl_app_info:t() | {error, Reason::term()}] |
+                          rcl_app_info:t() | {error, Reason::term()}.
+discover_dir(IgnoreDirs, File) ->
+    case (not lists:member(File, IgnoreDirs))
+        andalso filelib:is_dir(File) of
+        true ->
+            case file:list_dir(File) of
+                {error, Reason} ->
+                    {error, {accessing, File, Reason}};
+                {ok, List} ->
+                    ec_plists:map(fun(LibDir) ->
+                                     discover_dir(IgnoreDirs, LibDir)
+                                  end, [filename:join([File, Dir]) || Dir <- List])
+            end;
+        false ->
+            is_valid_otp_app(File)
+    end.
+
+-spec is_valid_otp_app(file:name()) -> rcl_app_info:t() | {error, Reason::term()} | [].
+is_valid_otp_app(File) ->
+    %% Is this an ebin dir?
+    EbinDir = filename:dirname(File),
+    case filename:basename(EbinDir) of
+        "ebin" ->
+            case lists:suffix(".app", File) of
+                true ->
+                    has_at_least_one_beam(EbinDir, File);
+                false ->
+                    []
+            end;
+        _ ->
+            []
+    end.
+
+-spec has_at_least_one_beam(file:name(), file:filename()) ->
+                                   rcl_app_info:t() | {error, Reason::term()}.
+has_at_least_one_beam(EbinDir, File) ->
+    case file:list_dir(EbinDir) of
+        {ok, List} ->
+            case lists:any(fun(NFile) -> lists:suffix(".beam", NFile) end, List) of
+                true ->
+                    gather_application_info(EbinDir, File);
+                false ->
+                    {error, {no_beam_files, EbinDir}}
+            end;
+        _ ->
+            {error, {not_a_directory, EbinDir}}
+    end.
+
+-spec gather_application_info(file:name(), file:filename()) ->
+                                     rcl_app_info:t() | {error, Reason::term()}.
+gather_application_info(EbinDir, File) ->
+    AppDir = filename:dirname(EbinDir),
+    case file:consult(File) of
+        {ok, [{application, AppName, AppDetail}]} ->
+            get_vsn(AppDir, AppName, AppDetail);
+        {error, Reason} ->
+            {error, {unable_to_load_app, AppDir, Reason}};
+        _ ->
+            {error, {invalid_app_file, File}}
+    end.
+
+-spec get_vsn(file:name(), atom(), proplists:proplist()) ->
+                     rcl_app_info:t() | {error, Reason::term()}.
+get_vsn(AppDir, AppName, AppDetail) ->
+    case proplists:get_value(vsn, AppDetail) of
+        undefined ->
+            {error, {unversioned_app, AppDir, AppName}};
+        AppVsn ->
+            case get_deps(AppDir, AppName, AppVsn, AppDetail) of
+                {ok, App} ->
+                    App;
+                {error, Detail} ->
+                    {error, {app_info_error, Detail}}
+            end
+    end.
+
+-spec get_deps(file:name(), atom(), string(), proplists:proplist()) ->
+                      {ok, rcl_app_info:t()} | {error, Reason::term()}.
+get_deps(AppDir, AppName, AppVsn, AppDetail) ->
+    ActiveApps = proplists:get_value(applications, AppDetail, []),
+    LibraryApps = proplists:get_value(included_applications, AppDetail, []),
+    rcl_app_info:new(AppName, AppVsn, AppDir, ActiveApps, LibraryApps).
+
+%%%===================================================================
+%%% Test Functions
+%%%===================================================================
+
+-ifndef(NOTEST).
+-include_lib("eunit/include/eunit.hrl").
+
+-endif.
diff --git a/src/rcl_prv_discover.erl b/src/rcl_prv_discover.erl
index 862bd6e..1ffbece 100644
--- a/src/rcl_prv_discover.erl
+++ b/src/rcl_prv_discover.erl
@@ -43,71 +43,22 @@ init(State) ->
 -spec do(rcl_state:t()) -> {ok, rcl_state:t()} | relcool:error().
 do(State) ->
     LibDirs = get_lib_dirs(State),
-    rcl_log:info(rcl_state:log(State),
-                  fun() ->
-                          ["Resolving OTP Applications from directories:\n",
-                           [[rcl_util:indent(1), LibDir, "\n"] || LibDir <- LibDirs]]
-                  end),
-    resolve_app_metadata(State, LibDirs).
+    case rcl_app_discovery:do(State, LibDirs) of
+        {ok, AppMeta} ->
+            {ok, rcl_state:available_apps(State, AppMeta)};
+        Error ->
+            Error
+    end.
 
--spec format_error([ErrorDetail::term()]) -> iolist().
-format_error(ErrorDetails)
-  when erlang:is_list(ErrorDetails) ->
-    [[format_detail(ErrorDetail), "\n"] || ErrorDetail <- ErrorDetails].
+%% @doc this is here to comply with the signature. However, we do not actually
+%% produce any errors and so simply return an empty string.
+-spec format_error(any()) -> iolist().
+format_error(_) ->
+    "".
 
 %%%===================================================================
 %%% Internal Functions
 %%%===================================================================
-resolve_app_metadata(State, LibDirs) ->
-    AppMeta0 = lists:flatten(ec_plists:map(fun(LibDir) ->
-                                               discover_dir([], LibDir)
-                                           end, LibDirs)),
-    AppMeta1 = setup_overrides(State, AppMeta0),
-
-    Errors = [case El of
-                  {error, Ret} -> Ret;
-                  _ -> El
-              end
-              || El <- AppMeta1,
-                 case El of
-                     {error, _} ->
-                         true;
-                     _ ->
-                         false
-                 end],
-
-    case Errors of
-        [] ->
-            AppMeta2 = lists:flatten(AppMeta1),
-            rcl_log:debug(rcl_state:log(State),
-                          fun() ->
-                                  ["Resolved the following OTP Applications from the system: \n",
-                                   [[rcl_app_info:format(1, App), "\n"] || App <- AppMeta2]]
-                          end),
-            {ok, rcl_state:available_apps(State, AppMeta2)};
-        _ ->
-            ?RCL_ERROR(Errors)
-    end.
-
-app_name({error, _}) ->
-    undefined;
-app_name(AppMeta) ->
-    rcl_app_info:name(AppMeta).
-
-setup_overrides(State, AppMetas0) ->
-    Overrides = rcl_state:overrides(State),
-    AppMetas1 = [AppMeta || AppMeta <- AppMetas0,
-                            not lists:keymember(app_name(AppMeta), 1, Overrides)],
-    [case is_valid_otp_app(filename:join([FileName, "ebin",
-                                         erlang:atom_to_list(AppName) ++ ".app"])) of
-         [] ->
-             {error, {invalid_override, AppName, FileName}};
-         Error = {error, _} ->
-             Error;
-         App ->
-             rcl_app_info:link(App, true)
-     end || {AppName, FileName} <- Overrides] ++ AppMetas1.
-
 get_lib_dirs(State) ->
     LibDirs0 = rcl_state:lib_dirs(State),
     case rcl_state:get(State, disable_default_libs, false) of
@@ -140,121 +91,3 @@ add_system_lib_dir(State, LibDirs) ->
                     LibDirs
             end
     end.
-
--spec format_detail(ErrorDetail::term()) -> iolist().
-format_detail({error, {invalid_override, AppName, FileName}}) ->
-    io_lib:format("Override {~p, ~p} is not a valid OTP App. Perhaps you forgot to build it?",
-                  [AppName, FileName]);
-format_detail({accessing, File, eaccess}) ->
-    io_lib:format("permission denied accessing file ~s", [File]);
-format_detail({accessing, File, Type}) ->
-    io_lib:format("error (~p) accessing file ~s", [Type, File]);
-format_detail({no_beam_files, EbinDir}) ->
-    io_lib:format("no beam files found in directory ~s", [EbinDir]);
-format_detail({not_a_directory, EbinDir}) ->
-    io_lib:format("~s is not a directory when it should be a directory", [EbinDir]);
-format_detail({unable_to_load_app, AppDir, _}) ->
-    io_lib:format("Unable to load the application metadata from ~s", [AppDir]);
-format_detail({invalid_app_file, File}) ->
-    io_lib:format("Application metadata file exists but is malformed: ~s",
-                  [File]);
-format_detail({unversioned_app, AppDir, _AppName}) ->
-    io_lib:format("Application metadata exists but version is not available: ~s",
-                  [AppDir]);
-format_detail({app_info_error, {Module, Detail}}) ->
-    Module:format_error(Detail).
-
--spec discover_dir([file:name()],
-                   file:name()) ->
-                          [rcl_app_info:t() | {error, Reason::term()}] |
-                          rcl_app_info:t() | {error, Reason::term()}.
-discover_dir(IgnoreDirs, File) ->
-    case (not lists:member(File, IgnoreDirs))
-        andalso filelib:is_dir(File) of
-        true ->
-            case file:list_dir(File) of
-                {error, Reason} ->
-                    {error, {accessing, File, Reason}};
-                {ok, List} ->
-                    ec_plists:map(fun(LibDir) ->
-                                     discover_dir(IgnoreDirs, LibDir)
-                                  end, [filename:join([File, Dir]) || Dir <- List])
-            end;
-        false ->
-            is_valid_otp_app(File)
-    end.
-
--spec is_valid_otp_app(file:name()) -> rcl_app_info:t() | {error, Reason::term()} | [].
-is_valid_otp_app(File) ->
-    %% Is this an ebin dir?
-    EbinDir = filename:dirname(File),
-    case filename:basename(EbinDir) of
-        "ebin" ->
-            case lists:suffix(".app", File) of
-                true ->
-                    has_at_least_one_beam(EbinDir, File);
-                false ->
-                    []
-            end;
-        _ ->
-            []
-    end.
-
--spec has_at_least_one_beam(file:name(), file:filename()) ->
-                                   rcl_app_info:t() | {error, Reason::term()}.
-has_at_least_one_beam(EbinDir, File) ->
-    case file:list_dir(EbinDir) of
-        {ok, List} ->
-            case lists:any(fun(NFile) -> lists:suffix(".beam", NFile) end, List) of
-                true ->
-                    gather_application_info(EbinDir, File);
-                false ->
-                    {error, {no_beam_files, EbinDir}}
-            end;
-        _ ->
-            {error, {not_a_directory, EbinDir}}
-    end.
-
--spec gather_application_info(file:name(), file:filename()) ->
-                                     rcl_app_info:t() | {error, Reason::term()}.
-gather_application_info(EbinDir, File) ->
-    AppDir = filename:dirname(EbinDir),
-    case file:consult(File) of
-        {ok, [{application, AppName, AppDetail}]} ->
-            get_vsn(AppDir, AppName, AppDetail);
-        {error, Reason} ->
-            {error, {unable_to_load_app, AppDir, Reason}};
-        _ ->
-            {error, {invalid_app_file, File}}
-    end.
-
--spec get_vsn(file:name(), atom(), proplists:proplist()) ->
-                     rcl_app_info:t() | {error, Reason::term()}.
-get_vsn(AppDir, AppName, AppDetail) ->
-    case proplists:get_value(vsn, AppDetail) of
-        undefined ->
-            {error, {unversioned_app, AppDir, AppName}};
-        AppVsn ->
-            case get_deps(AppDir, AppName, AppVsn, AppDetail) of
-                {ok, App} ->
-                    App;
-                {error, Detail} ->
-                    {error, {app_info_error, Detail}}
-            end
-    end.
-
--spec get_deps(file:name(), atom(), string(), proplists:proplist()) ->
-                      {ok, rcl_app_info:t()} | {error, Reason::term()}.
-get_deps(AppDir, AppName, AppVsn, AppDetail) ->
-    ActiveApps = proplists:get_value(applications, AppDetail, []),
-    LibraryApps = proplists:get_value(included_applications, AppDetail, []),
-    rcl_app_info:new(AppName, AppVsn, AppDir, ActiveApps, LibraryApps).
-
-%%%===================================================================
-%%% Test Functions
-%%%===================================================================
-
--ifndef(NOTEST).
--include_lib("eunit/include/eunit.hrl").
-
--endif.