From faddc82d3c8c25fbddb1074d511582b8ac020c38 Mon Sep 17 00:00:00 2001
From: Bikram Chatterjee <chatterjee@bluewin.ch>
Date: Mon, 23 Oct 2017 12:06:51 +0200
Subject: fix win32 share filename join/split (#1604)

Handle UNC (shared) path on win32, previously  "//dir/.." and "\\\\dir\.." was cleaned up to
"/dir/.." which was not correct.

OTP-14693
---
 lib/stdlib/src/filename.erl | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

(limited to 'lib/stdlib/src')

diff --git a/lib/stdlib/src/filename.erl b/lib/stdlib/src/filename.erl
index 9bf4290916..ee807dfd09 100644
--- a/lib/stdlib/src/filename.erl
+++ b/lib/stdlib/src/filename.erl
@@ -439,6 +439,10 @@ join(Name1, Name2) when is_atom(Name2) ->
 join1([UcLetter, $:|Rest], RelativeName, [], win32)
 when is_integer(UcLetter), UcLetter >= $A, UcLetter =< $Z ->
     join1(Rest, RelativeName, [$:, UcLetter+$a-$A], win32);
+join1([$\\,$\\|Rest], RelativeName, [], win32) ->
+    join1([$/,$/|Rest], RelativeName, [], win32);
+join1([$/,$/|Rest], RelativeName, [], win32) ->
+    join1(Rest, RelativeName, [$/,$/], win32);
 join1([$\\|Rest], RelativeName, Result, win32) ->
     join1([$/|Rest], RelativeName, Result, win32);
 join1([$/|Rest], RelativeName, [$., $/|Result], OsType) ->
@@ -467,6 +471,10 @@ join1([Atom|Rest], RelativeName, Result, OsType) when is_atom(Atom) ->
 join1b(<<UcLetter, $:, Rest/binary>>, RelativeName, [], win32)
 when is_integer(UcLetter), UcLetter >= $A, UcLetter =< $Z ->
     join1b(Rest, RelativeName, [$:, UcLetter+$a-$A], win32);
+join1b(<<$\\,$\\,Rest/binary>>, RelativeName, [], win32) ->
+    join1b(<<$/,$/,Rest/binary>>, RelativeName, [], win32);
+join1b(<<$/,$/,Rest/binary>>, RelativeName, [], win32) ->
+    join1b(Rest, RelativeName, [$/,$/], win32);
 join1b(<<$\\,Rest/binary>>, RelativeName, Result, win32) ->
     join1b(<<$/,Rest/binary>>, RelativeName, Result, win32);
 join1b(<<$/,Rest/binary>>, RelativeName, [$., $/|Result], OsType) ->
@@ -477,6 +485,8 @@ join1b(<<>>, <<>>, Result, OsType) ->
     list_to_binary(maybe_remove_dirsep(Result, OsType));
 join1b(<<>>, RelativeName, [$:|Rest], win32) ->
     join1b(RelativeName, <<>>, [$:|Rest], win32);
+join1b(<<>>, RelativeName, [$/,$/|Result], win32) ->
+    join1b(RelativeName, <<>>, [$/,$/|Result], win32);
 join1b(<<>>, RelativeName, [$/|Result], OsType) ->
     join1b(RelativeName, <<>>, [$/|Result], OsType);
 join1b(<<>>, RelativeName, [$., $/|Result], OsType) ->
@@ -490,6 +500,8 @@ maybe_remove_dirsep([$/, $:, Letter], win32) ->
     [Letter, $:, $/];
 maybe_remove_dirsep([$/], _) ->
     [$/];
+maybe_remove_dirsep([$/,$/], win32) ->
+    [$/,$/];
 maybe_remove_dirsep([$/|Name], _) ->
     lists:reverse(Name);
 maybe_remove_dirsep(Name, _) ->
@@ -679,6 +691,9 @@ win32_splitb(<<Letter0,$:,Rest/binary>>) when ?IS_DRIVELETTER(Letter0) ->
     Letter = fix_driveletter(Letter0),
     L = binary:split(Rest,[<<"/">>,<<"\\">>],[global]),
     [<<Letter,$:>> | [ X || X <- L, X =/= <<>> ]];
+win32_splitb(<<Slash,Slash,Rest/binary>>) when ((Slash =:= $\\) orelse (Slash =:= $/)) ->
+    L = binary:split(Rest,[<<"/">>,<<"\\">>],[global]),
+    [<<"//">> | [ X || X <- L, X =/= <<>> ]];
 win32_splitb(<<Slash,Rest/binary>>) when ((Slash =:= $\\) orelse (Slash =:= $/)) ->
     L = binary:split(Rest,[<<"/">>,<<"\\">>],[global]),
     [<<$/>> | [ X || X <- L, X =/= <<>> ]];
@@ -690,6 +705,8 @@ win32_splitb(Name) ->
 unix_split(Name) ->
     split(Name, [], unix).
 
+win32_split([Slash,Slash|Rest]) when ((Slash =:= $\\) orelse (Slash =:= $/)) ->
+    split(Rest, [[$/,$/]], win32);
 win32_split([$\\|Rest]) ->
     win32_split([$/|Rest]);
 win32_split([X, $\\|Rest]) when is_integer(X) ->
-- 
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