From 57aaf7d0c7c75cfd8c6b55c21d977b695f460022 Mon Sep 17 00:00:00 2001
From: Richard Carlsson <richardc@klarna.com>
Date: Wed, 18 Jan 2017 18:28:47 +0100
Subject: Add filelib:find_file/2/3 and filelib:find_source/1/2/3

This moves, extends and exports functionality that previously existed only
internally in filename:find_src/1/2, adding the ability to automatically
substitute file suffixes and use different rules for different suffixes.
---
 lib/stdlib/src/filename.erl | 74 ++++++++++-----------------------------------
 1 file changed, 16 insertions(+), 58 deletions(-)

(limited to 'lib/stdlib/src/filename.erl')

diff --git a/lib/stdlib/src/filename.erl b/lib/stdlib/src/filename.erl
index 51d5ca711d..0ff22f876a 100644
--- a/lib/stdlib/src/filename.erl
+++ b/lib/stdlib/src/filename.erl
@@ -34,8 +34,8 @@
 -export([absname/1, absname/2, absname_join/2, 
 	 basename/1, basename/2, dirname/1,
 	 extension/1, join/1, join/2, pathtype/1,
-	 rootname/1, rootname/2, split/1, nativename/1]).
--export([find_src/1, find_src/2, flatten/1]).
+	 rootname/1, rootname/2, split/1, flatten/1, nativename/1]).
+-export([find_src/1, find_src/2]). % deprecated
 -export([basedir/2, basedir/3]).
 
 %% Undocumented and unsupported exports.
@@ -750,8 +750,12 @@ separators() ->
 	_ -> {false, false}
     end.
 
-
-
+%% NOTE: The find_src/1/2 functions are deprecated; they try to do too much
+%% at once and are not a good fit for this module. Parts of the code have
+%% been moved to filelib:find_file/2 instead. Only this part of this
+%% module is allowed to call the filelib module; such mutual dependency
+%% should otherwise be avoided! This code should eventually be removed.
+%%
 %% find_src(Module) --
 %% find_src(Module, Rules) --
 %%
@@ -815,26 +819,27 @@ find_src(ModOrFile, Rules) when is_list(ModOrFile) ->
     case code:which(Mod) of
 	Possibly_Rel_Path when is_list(Possibly_Rel_Path) ->
             {ok, Cwd} = file:get_cwd(),
-            Dir = dirname(make_abs_path(Cwd, Possibly_Rel_Path)),
-            find_src_1(ModOrFile, Dir, Mod, Extension, Rules);
+            ObjPath = make_abs_path(Cwd, Possibly_Rel_Path),
+            find_src_1(ModOrFile, ObjPath, Mod, Extension, Rules);
 	Ecode when is_atom(Ecode) -> % Ecode :: ecode()
 	    {error, {Ecode, Mod}}
     end.
 
 %% At this point, the Mod is known to be valid.
 %% If the source name is not known, find it.
-find_src_1(ModOrFile, Dir, Mod, Extension, Rules) ->
+find_src_1(ModOrFile, ObjPath, Mod, Extension, Rules) ->
     %% The documentation says this function must return the found path
     %% without extension in all cases. Also, ModOrFile could be given with
     %% or without extension. Hence the calls to rootname below.
     ModOrFileRoot = rootname(ModOrFile, Extension),
-    case readable_file(ModOrFileRoot++Extension) of
+    case filelib:is_regular(ModOrFileRoot++Extension) of
         true  ->
             find_src_2(ModOrFileRoot, Mod);
         false ->
-            case get_source_file(Dir, atom_to_list(Mod)++Extension, Rules) of
-                {ok, Src} ->
-                    find_src_2(rootname(Src, Extension), Mod);
+            SrcName = basename(ObjPath, code:objfile_extension()) ++ Extension,
+            case filelib:find_file(SrcName, dirname(ObjPath), Rules) of
+                {ok, SrcFile} ->
+                    find_src_2(rootname(SrcFile, Extension), Mod);
                 Error ->
                     Error
             end
@@ -879,53 +884,6 @@ filter_options(Base, [_|Rest], Result) ->
 filter_options(_Base, [], Result) ->
     Result.
 
-%% Gets the source file given the object directory.
-
-get_source_file(Dir, Filename, []) ->
-    Rules =
-	case application:get_env(kernel, source_search_rules) of
-	    undefined -> default_source_search_rules();
-	    {ok, []} -> default_source_search_rules();
-	    {ok, R} when is_list(R) -> R
-	end,
-    get_source_file(Dir, Filename, Rules);
-get_source_file(Dir, Filename, Rules) ->
-    source_by_rules(Dir, Filename, Rules).
-
-default_source_search_rules() ->
-    [{"", ""}, {"ebin", "src"}, {"ebin", "esrc"}].
-
-source_by_rules(Dir, Filename, [{From, To}|Rest]) ->
-    case try_rule(Dir, Filename, From, To) of
-	{ok, File} -> {ok, File};
-	error      -> source_by_rules(Dir, Filename, Rest)
-    end;
-source_by_rules(_Dir, _Filename, []) ->
-    {error, source_file_not_found}.
-
-try_rule(Dir, Filename, From, To) ->
-    case lists:suffix(From, Dir) of
-	true -> 
-	    NewDir = lists:sublist(Dir, 1, length(Dir)-length(From))++To,
-	    Src = join(NewDir, Filename),
-	    case readable_file(Src) of
-		true -> {ok, Src};
-		false -> error
-	    end;
-	false ->
-	    error
-    end.
-
-readable_file(File) ->
-    case file:read_file_info(File) of
-	{ok, #file_info{type=regular, access=read}} ->
-	    true;
-	{ok, #file_info{type=regular, access=read_write}} ->
-	    true;
-	_Other ->
-	    false
-    end.
-
 make_abs_path(BasePath, Path) ->
     join(BasePath, Path).
 
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