Merge pull request #1567 from bjorng/bjorn/stdlib/wildcard-escaping/ERL-451/OTP-14577

Implement escaping of special characters in wildcards

3 files changed, 76 insertions, 4 deletions

diff --git a/lib/stdlib/doc/src/filelib.xml b/lib/stdlib/doc/src/filelib.xml
index 57c4348745..1b69e84d31 100644
--- a/lib/stdlib/doc/src/filelib.xml
+++ b/lib/stdlib/doc/src/filelib.xml
@@ -217,6 +217,11 @@
         <p>Other characters represent themselves. Only filenames that
           have exactly the same character in the same position match.
           Matching is case-sensitive, for example, "a" does not match "A".</p>
+	<p>Directory separators must always be written as <c>/</c>, even on
+	Windows.</p>
+	<p>A character preceded by <c>\</c> loses its special meaning. Note
+	that <c>\</c> must be written as <c>\\</c> in a string literal.
+	For example, "\\?*" will match any filename starting with <c>?</c>.</p>
         <p>Notice that multiple "*" characters are allowed
           (as in Unix wildcards, but opposed to Windows/DOS wildcards).</p>
         <p><em>Examples:</em></p>
diff --git a/lib/stdlib/src/filelib.erl b/lib/stdlib/src/filelib.erl
index d7c313f214..0f90b3fc33 100644
--- a/lib/stdlib/src/filelib.erl
+++ b/lib/stdlib/src/filelib.erl
@@ -365,11 +365,18 @@ do_list_dir(Dir, Mod) ->     eval_list_dir(Dir, Mod).
 	    
 %%% Compiling a wildcard.
 
+
+%% Define characters used for escaping a \.
+-define(ESCAPE_PREFIX, $@).
+-define(ESCAPE_CHARACTER, [?ESCAPE_PREFIX,$e]).
+-define(ESCAPED_ESCAPE_PREFIX, [?ESCAPE_PREFIX,?ESCAPE_PREFIX]).
+
 %% Only for debugging.
 compile_wildcard(Pattern) when is_list(Pattern) ->
     {compiled_wildcard,?HANDLE_ERROR(compile_wildcard(Pattern, "."))}.
 
-compile_wildcard(Pattern, Cwd0) ->
+compile_wildcard(Pattern0, Cwd0) ->
+    Pattern = convert_escapes(Pattern0),
     [Root|Rest] = filename:split(Pattern),
     case filename:pathtype(Root) of
 	relative ->
@@ -409,7 +416,8 @@ compile_join({cwd,Cwd}, File0) ->
 compile_join({root,PrefixLen,Root}, File) ->
     {root,PrefixLen,filename:join(Root, File)}.
 
-compile_part(Part) ->
+compile_part(Part0) ->
+    Part = wrap_escapes(Part0),
     compile_part(Part, false, []).
 
 compile_part_to_sep(Part) ->
@@ -445,6 +453,8 @@ compile_part([${|Rest], Upto, Result) ->
 	error ->
 	    compile_part(Rest, Upto, [${|Result])
     end;
+compile_part([{escaped,X}|Rest], Upto, Result) ->
+    compile_part(Rest, Upto, [X|Result]);
 compile_part([X|Rest], Upto, Result) ->
     compile_part(Rest, Upto, [X|Result]);
 compile_part([], _Upto, Result) ->
@@ -461,6 +471,8 @@ compile_charset1([Lower, $-, Upper|Rest], Ordset) when Lower =< Upper ->
     compile_charset1(Rest, compile_range(Lower, Upper, Ordset));
 compile_charset1([$]|Rest], Ordset) ->
     {ok, {one_of, gb_sets:from_ordset(Ordset)}, Rest};
+compile_charset1([{escaped,X}|Rest], Ordset) ->
+    compile_charset1(Rest, ordsets:add_element(X, Ordset));
 compile_charset1([X|Rest], Ordset) ->
     compile_charset1(Rest, ordsets:add_element(X, Ordset));
 compile_charset1([], _Ordset) ->
@@ -486,6 +498,32 @@ compile_alt(Pattern, Result) ->
 	    error
     end.
 
+%% Convert backslashes to an illegal Unicode character to
+%% protect in from filename:split/1.
+
+convert_escapes([?ESCAPE_PREFIX|T]) ->
+    ?ESCAPED_ESCAPE_PREFIX ++ convert_escapes(T);
+convert_escapes([$\\|T]) ->
+    ?ESCAPE_CHARACTER ++ convert_escapes(T);
+convert_escapes([H|T]) ->
+    [H|convert_escapes(T)];
+convert_escapes([]) ->
+    [].
+
+%% Wrap each escape in a tuple to remove the special meaning for
+%% the character that follows.
+
+wrap_escapes(?ESCAPED_ESCAPE_PREFIX ++ T) ->
+    [?ESCAPE_PREFIX|wrap_escapes(T)];
+wrap_escapes(?ESCAPE_CHARACTER ++ [C|T]) ->
+    [{escaped,C}|wrap_escapes(T)];
+wrap_escapes(?ESCAPE_CHARACTER) ->
+    [];
+wrap_escapes([H|T]) ->
+    [H|wrap_escapes(T)];
+wrap_escapes([]) ->
+    [].
+
 badpattern(Reason) ->
     error({badpattern,Reason}).
 
diff --git a/lib/stdlib/test/filelib_SUITE.erl b/lib/stdlib/test/filelib_SUITE.erl
index c94821bc75..1236fe45f4 100644
--- a/lib/stdlib/test/filelib_SUITE.erl
+++ b/lib/stdlib/test/filelib_SUITE.erl
@@ -120,7 +120,7 @@ wcc(Wc, Error) ->
 do_wildcard_1(Dir, Wcf0) ->
     do_wildcard_2(Dir, Wcf0),
     Wcf = fun(Wc0) ->
-		  Wc = filename:join(Dir, Wc0),
+		  Wc = Dir ++ "/" ++ Wc0,
 		  L = Wcf0(Wc),
 		  [subtract_dir(N, Dir) || N <- L]
 	  end,
@@ -268,8 +268,37 @@ do_wildcard_9(Dir, Wcf) ->
     %% Cleanup.
     del(Files),
     [ok = file:del_dir(D) || D <- lists:reverse(Dirs)],
-    ok.
+    do_wildcard_10(Dir, Wcf).
+
+%% ERL-451/OTP-14577: Escape characters using \\.
+do_wildcard_10(Dir, Wcf) ->
+    All0 = ["{abc}","abc","def","---","z--","@a,b","@c"],
+    All = case os:type() of
+              {unix,_} ->
+                  %% '?' is allowed in file names on Unix, but
+                  %% not on Windows.
+                  ["?q"|All0];
+              _ ->
+                  All0
+          end,
+    Files = mkfiles(lists:reverse(All), Dir),
+
+    ["{abc}"] = Wcf("\\{a*"),
+    ["{abc}"] = Wcf("\\{abc}"),
+    ["abc","def","z--"] = Wcf("[a-z]*"),
+    ["---","abc","z--"] = Wcf("[a\\-z]*"),
+    ["@a,b","@c"] = Wcf("@{a\\,b,c}"),
+    ["@c"] = Wcf("@{a,b,c}"),
+
+    case os:type() of
+        {unix,_} ->
+            ["?q"] = Wcf("\\?q");
+        _ ->
+            [] = Wcf("\\?q")
+    end,
 
+    del(Files),
+    ok.
 
 fold_files(Config) when is_list(Config) ->
     Dir = filename:join(proplists:get_value(priv_dir, Config), "fold_files"),