Rethink the filelib:wildcard() functions

Commit 70b5e24c9498225fadc08d19503269c8aad851bf broke
filelib:wildcard(Pattern, ".").

Over the years, the logic for filelib:wilcard() has become a mess
of special cases.

Probably because of premature optimization, filelib:wildcard(Pattern)
and filelib:wildcard(Pattern, Cwd) are handled differently.
They can be consolidated if we use a "." as the default Cwd argument.

We can also simplify things by compiling the Cwd argument into the
wildcard. We did not that in the initial implementation because it
used to be possible to pre-compile a wildcard and pass it to
filelib:wildcard/{1,2}. Since that is no longer possible, there is
no point in keeping the compiled wildcard "portable" (not dependent
on the Cwd argument).

1 files changed, 55 insertions, 69 deletions

diff --git a/lib/stdlib/src/filelib.erl b/lib/stdlib/src/filelib.erl
index fec9d0ac23..b1a5b7a8a9 100644
--- a/lib/stdlib/src/filelib.erl
+++ b/lib/stdlib/src/filelib.erl
@@ -19,13 +19,14 @@
 -module(filelib).
 
 %% File utilities.
--export([wildcard/1, wildcard/2, is_dir/1, is_file/1, is_regular/1, 
-	 compile_wildcard/1]).
+-export([wildcard/1, wildcard/2, is_dir/1, is_file/1, is_regular/1]).
 -export([fold_files/5, last_modified/1, file_size/1, ensure_dir/1]).
-
 -export([wildcard/3, is_dir/2, is_file/2, is_regular/2]).
 -export([fold_files/6, last_modified/2, file_size/2]).
 
+%% For debugging/testing.
+-export([compile_wildcard/1]).
+
 -include_lib("kernel/include/file.hrl").
 
 -define(HANDLE_ERROR(Expr),
@@ -45,7 +46,7 @@
 -spec wildcard(Wildcard) -> [file:filename()] when
       Wildcard :: filename() | dirname().
 wildcard(Pattern) when is_list(Pattern) ->
-    ?HANDLE_ERROR(do_wildcard(Pattern, file)).
+    ?HANDLE_ERROR(do_wildcard(Pattern, ".", file)).
 
 -spec wildcard(Wildcard, Cwd) -> [file:filename()] when
       Wildcard :: filename() | dirname(),
@@ -53,7 +54,7 @@ wildcard(Pattern) when is_list(Pattern) ->
 wildcard(Pattern, Cwd) when is_list(Pattern), is_list(Cwd) ->
     ?HANDLE_ERROR(do_wildcard(Pattern, Cwd, file));
 wildcard(Pattern, Mod) when is_list(Pattern), is_atom(Mod) ->
-    ?HANDLE_ERROR(do_wildcard(Pattern, Mod)).
+    ?HANDLE_ERROR(do_wildcard(Pattern, ".", Mod)).
 
 -spec wildcard(file:name(), file:name(), atom()) -> [file:filename()].
 wildcard(Pattern, Cwd, Mod)
@@ -121,47 +122,6 @@ file_size(File, Mod) when is_atom(Mod) ->
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-do_wildcard(Pattern, Mod) when is_list(Pattern) ->
-    do_wildcard_comp(do_compile_wildcard(Pattern), Mod).
-
-do_wildcard_comp({compiled_wildcard,{exists,File}}, Mod) ->
-    case eval_read_file_info(File, Mod) of
-	{ok,_} -> [File];
-	_ -> []
-    end;
-do_wildcard_comp({compiled_wildcard,[cwd,Base|Rest]}, Mod) ->
-    do_wildcard_1([Base], Rest, Mod);
-do_wildcard_comp({compiled_wildcard,[Base|Rest]}, Mod) ->
-    do_wildcard_1([Base], Rest, Mod).
-
-do_wildcard(Pattern, Cwd, Mod) when is_list(Pattern), (is_list(Cwd) or is_binary(Cwd)) ->
-    do_wildcard_comp(do_compile_wildcard(Pattern), Cwd, Mod).
-
-do_wildcard_comp({compiled_wildcard,{exists,File}}, Cwd, Mod) ->
-    case eval_read_file_info(filename:absname(File, Cwd), Mod) of
-	{ok,_} -> [File];
-	_ -> []
-    end;
-do_wildcard_comp({compiled_wildcard,[cwd|Rest0]}, Cwd0, Mod) ->
-    case Rest0 of
-	[current|Rest] -> ok;
-	Rest -> ok
-    end,
-    {Cwd,PrefixLen} = case filename:join([Cwd0]) of
-	      Bin when is_binary(Bin) -> {Bin,byte_size(Bin)+1};
-	      Other -> {Other,length(Other)+1}
-	  end,		%Slash away redundant slashes.
-    [
-     if 
-	 is_binary(N) ->
-	     <<_:PrefixLen/binary,Res/binary>> = N,
-	     Res;
-	 true ->
-	     lists:nthtail(PrefixLen, N)
-     end || N <- do_wildcard_1([Cwd], Rest, Mod)];
-do_wildcard_comp({compiled_wildcard,[Base|Rest]}, _Cwd, Mod) ->
-    do_wildcard_1([Base], Rest, Mod).
-
 do_is_dir(Dir, Mod) ->
     case eval_read_file_info(Dir, Mod) of
 	{ok, #file_info{type=directory}} ->
@@ -290,8 +250,23 @@ ensure_dir(F) ->
 %%% Pattern matching using a compiled wildcard.
 %%%
 
-do_wildcard_1(Files, Pattern, Mod) ->
-    do_wildcard_2(Files, Pattern, [], Mod).
+do_wildcard(Pattern, Cwd, Mod) ->
+    {Compiled,PrefixLen} = compile_wildcard(Pattern, Cwd),
+    Files = do_wildcard_1(Compiled, Mod),
+    if
+	PrefixLen =:= 0 ->
+	    Files;
+	true ->
+	    [lists:nthtail(PrefixLen, File) || File <- Files]
+    end.
+
+do_wildcard_1({exists,File}, Mod) ->
+    case eval_read_file_info(File, Mod) of
+	{ok,_} -> [File];
+	_ -> []
+    end;
+do_wildcard_1([Base|Rest], Mod) ->
+    do_wildcard_2([Base], Rest, [], Mod).
 
 do_wildcard_2([File|Rest], Pattern, Result, Mod) ->
     do_wildcard_2(Rest, Pattern, do_wildcard_3(File, Pattern, Result, Mod), Mod);
@@ -299,7 +274,7 @@ do_wildcard_2([], _, Result, _Mod) ->
     Result.
 
 do_wildcard_3(Base, [[double_star]|Rest], Result, Mod) ->
-    lists:sort(do_double_star(current, [Base], Rest, Result, Mod, true));
+    lists:sort(do_double_star(".", [Base], Rest, Result, Mod, true));
 do_wildcard_3(Base, [Pattern|Rest], Result, Mod) ->
     case do_list_dir(Base, Mod) of
 	{ok, Files0} ->
@@ -315,7 +290,7 @@ do_wildcard_3(Base, [], Result, _Mod) ->
 wildcard_4(Pattern, [File|Rest], Base, Result) ->
     case wildcard_5(Pattern, File) of
 	true ->
-	    wildcard_4(Pattern, Rest, Base, [join(Base, File)|Result]);
+	    wildcard_4(Pattern, Rest, Base, [filename:join(Base, File)|Result]);
 	false ->
 	    wildcard_4(Pattern, Rest, Base, Result)
     end;
@@ -349,7 +324,10 @@ wildcard_5([_|_], []) ->
     false.
 
 do_double_star(Base, [H|T], Rest, Result, Mod, Root) ->
-    Full = join(Base, H),
+    Full = case Root of
+	       false -> filename:join(Base, H);
+	       true -> H
+	   end,
     Result1 = case do_list_dir(Full, Mod) of
         {ok, Files} ->
             do_double_star(Full, Files, Rest, Result, Mod, false);
@@ -379,46 +357,54 @@ do_alt([Alt|Rest], File) ->
 do_alt([], _File) ->
     false.
 
-do_list_dir(current, Mod) -> eval_list_dir(".", Mod);
 do_list_dir(Dir, Mod) ->     eval_list_dir(Dir, Mod).
 
-join(current, File) -> File;
-join(Base, File) -> filename:join(Base, File).
-
 	    
 %%% Compiling a wildcard.
 
-compile_wildcard(Pattern) ->
-    ?HANDLE_ERROR(do_compile_wildcard(Pattern)).
-
-do_compile_wildcard(Pattern) ->
-    {compiled_wildcard,compile_wildcard_1(Pattern)}.
+%% Only for debugging.
+compile_wildcard(Pattern) when is_list(Pattern) ->
+    {compiled_wildcard,?HANDLE_ERROR(compile_wildcard(Pattern, "."))}.
 
-compile_wildcard_1(Pattern) ->
+compile_wildcard(Pattern, Cwd0) ->
     [Root|Rest] = filename:split(Pattern),
     case filename:pathtype(Root) of
 	relative ->
-	    case compile_wildcard_2([Root|Rest], current) of
-		{exists,_}=Wc -> Wc;
-		[_|_]=Wc -> [cwd|Wc]
-	    end;
+	    Cwd = filename:join([Cwd0]),
+	    compile_wildcard_2([Root|Rest], {cwd,Cwd});
 	_ ->
-	    compile_wildcard_2(Rest, [Root])
+	    compile_wildcard_2(Rest, {root,0,Root})
     end.
 
 compile_wildcard_2([Part|Rest], Root) ->
     case compile_part(Part) of
 	Part ->
-	    compile_wildcard_2(Rest, join(Root, Part));
+	    compile_wildcard_2(Rest, compile_join(Root, Part));
 	Pattern ->
 	    compile_wildcard_3(Rest, [Pattern,Root])
     end;
-compile_wildcard_2([], Root) -> {exists,Root}.
+compile_wildcard_2([], {root,PrefixLen,Root}) ->
+    {{exists,Root},PrefixLen}.
 
 compile_wildcard_3([Part|Rest], Result) ->
     compile_wildcard_3(Rest, [compile_part(Part)|Result]);
 compile_wildcard_3([], Result) ->
-    lists:reverse(Result).
+    case lists:reverse(Result) of
+	[{root,PrefixLen,Root}|Compiled] ->
+	    {[Root|Compiled],PrefixLen};
+	[{cwd,Root}|Compiled] ->
+	    {[Root|Compiled],length(filename:join(Root, "x"))-1}
+    end.
+
+compile_join({cwd,"."}, File) ->
+    {root,0,File};
+compile_join({cwd,Cwd}, File0) ->
+    File = filename:join([File0]),
+    Root = filename:join(Cwd, File),
+    PrefixLen = length(Root) - length(File),
+    {root,PrefixLen,Root};
+compile_join({root,PrefixLen,Root}, File) ->
+    {root,PrefixLen,filename:join(Root, File)}.
 
 compile_part(Part) ->
     compile_part(Part, false, []).