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-rw-r--r--lib/stdlib/src/filename.erl37
1 files changed, 36 insertions, 1 deletions
diff --git a/lib/stdlib/src/filename.erl b/lib/stdlib/src/filename.erl
index 2a2f25dcd2..b5df5c9d37 100644
--- a/lib/stdlib/src/filename.erl
+++ b/lib/stdlib/src/filename.erl
@@ -37,7 +37,8 @@
-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, flatten/1, nativename/1]).
+ rootname/1, rootname/2, split/1, flatten/1, nativename/1,
+ safe_relative_path/1]).
-export([find_src/1, find_src/2]). % deprecated
-export([basedir/2, basedir/3]).
@@ -753,12 +754,46 @@ separators() ->
_ -> {false, false}
end.
+-spec safe_relative_path(Filename) -> 'unsafe' | SafeFilename when
+ Filename :: file:name_all(),
+ SafeFilename :: file:name_all().
+
+safe_relative_path(Path) ->
+ case pathtype(Path) of
+ relative ->
+ Cs0 = split(Path),
+ safe_relative_path_1(Cs0, []);
+ _ ->
+ unsafe
+ end.
+
+safe_relative_path_1(["."|T], Acc) ->
+ safe_relative_path_1(T, Acc);
+safe_relative_path_1([<<".">>|T], Acc) ->
+ safe_relative_path_1(T, Acc);
+safe_relative_path_1([".."|T], Acc) ->
+ climb(T, Acc);
+safe_relative_path_1([<<"..">>|T], Acc) ->
+ climb(T, Acc);
+safe_relative_path_1([H|T], Acc) ->
+ safe_relative_path_1(T, [H|Acc]);
+safe_relative_path_1([], []) ->
+ [];
+safe_relative_path_1([], Acc) ->
+ join(lists:reverse(Acc)).
+
+climb(_, []) ->
+ unsafe;
+climb(T, [_|Acc]) ->
+ safe_relative_path_1(T, Acc).
+
%% 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) --
%%