FileURLToFilePath: Don't unescape '/' and '\\'.

net/base/filename_util_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/filename_util.h"
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 221 matching lines @@
   FileCase url_cases[] = {
 #if defined(OS_WIN)
     {L"C:\\foo\\bar.txt", "file:c|/foo\\bar.txt"},
     {L"C:\\foo\\bar.txt", "file:/c:/foo/bar.txt"},
     {L"\\\\foo\\bar.txt", "file://foo\\bar.txt"},
     {L"C:\\foo\\bar.txt", "file:///c:/foo/bar.txt"},
     {L"\\\\foo\\bar.txt", "file:////foo\\bar.txt"},
     {L"\\\\foo\\bar.txt", "file:/foo/bar.txt"},
     {L"\\\\foo\\bar.txt", "file://foo\\bar.txt"},
     {L"C:\\foo\\bar.txt", "file:\\\\\\c:/foo/bar.txt"},
+    // %2f ('/') and %5c ('\\') are left alone by both GURL and
+    // FileURLToFilePath.
+    {L"C:\\foo%2f..%5cbar", "file:///C:\\foo%2f..%5cbar"},

[eroman, 2016/02/18 19:37:28]

What are the unescaping rules for %2e   (dot) ?

[mmenke, 2016/02/18 20:30:22]

Dots are unescaped in paths, since they have no magic meaning http or file URLs
(They may have a magic meaning to the OS for how to handle opening, but that's
another matter).

The periods removed in the other test I added are removed because of magic code
to sanitize a file name for download.

[eroman, 2016/02/18 21:17:22]

But dots do have a magical meaning, which is no less magical than slashes and
backslashes IMO.

GURL will collapse paths during canonicalization, so for instance
   foo/bar/../x ---> foo/x

Right?

This will also occur when the dots are percent escaped, as in %2e%2e.

So from a policy perspective I still don't really understand why we would choose
to unescape dots, but not slashes and backslashes.

Both have implications for how file paths are opened on disk.

I get that this CL is trying to at least match the consistency from the point of
view of GURL, and LGTM from that side. But as a larger policy I don't quite
understand why special preference for slashes but not dots.

 #elif defined(OS_POSIX)
     {L"/c:/foo/bar.txt", "file:/c:/foo/bar.txt"},
     {L"/c:/foo/bar.txt", "file:///c:/foo/bar.txt"},
     {L"/foo/bar.txt", "file:/foo/bar.txt"},
     {L"/c:/foo/bar.txt", "file:\\\\\\c:/foo/bar.txt"},
     {L"/foo/bar.txt", "file:foo/bar.txt"},
     {L"/bar.txt", "file://foo/bar.txt"},
     {L"/foo/bar.txt", "file:///foo/bar.txt"},
     {L"/foo/bar.txt", "file:////foo/bar.txt"},
     {L"/foo/bar.txt", "file:////foo//bar.txt"},
     {L"/foo/bar.txt", "file:////foo///bar.txt"},
     {L"/foo/bar.txt", "file:////foo////bar.txt"},
     {L"/c:/foo/bar.txt", "file:\\\\\\c:/foo/bar.txt"},
     {L"/c:/foo/bar.txt", "file:c:/foo/bar.txt"},
+    // %2f ('/') and %5c ('\\') are left alone by both GURL and
+    // FileURLToFilePath.
+    {L"/foo%2f..%5cbar", "file:///foo%2f..%5cbar"},
 //  We get these wrong because GURL turns back slashes into forward
 //  slashes.
 //  {L"/foo%5Cbar.txt", "file://foo\\bar.txt"},
 //  {L"/c|/foo%5Cbar.txt", "file:c|/foo\\bar.txt"},
 //  {L"/foo%5Cbar.txt", "file://foo\\bar.txt"},
 //  {L"/foo%5Cbar.txt", "file:////foo\\bar.txt"},
 //  {L"/foo%5Cbar.txt", "file://foo\\bar.txt"},
 #endif
   };
   for (size_t i = 0; i < arraysize(url_cases); i++) {
@@ skipping 512 matching lines @@
      L"\uc608\uc220 \uc608\uc220.jpg"},
     {// Invalid C-D. No filename from URL. Falls back to 'download'.
      __LINE__,
      "http://www.google.com/path1/path2/",
      "attachment; filename==?iso88591?Q?caf=E3?",
      "",
      "",
      "image/jpeg",
      L"download",
      L"download" JPEG_EXT},
+    {// Escaped slash, backslash, and leading periods in file name. The periods
+     // should be removed, both slashes replaced with dashes.
+     __LINE__,
+     "http://www.google.com/..%2f%5ctest.html",
+     "",
+     "",
+     "",
+     "",
+     L"",
+     L"--test.html"},
   };
 
   // Tests filename generation.  Once the correct filename is
   // selected, they should be passed through the validation steps and
   // a correct extension should be added if necessary.
   const GenerateFilenameCase generation_tests[] = {
     // Dotfiles. Ensures preceeding period(s) stripped.
     {__LINE__, "http://www.google.com/.test.html", "", "", "", "", L"",
      L"test.html"},
     {__LINE__, "http://www.google.com/.test", "", "", "", "", L"", L"test"},
@@ skipping 269 matching lines @@
   }
 
   for (size_t i = 0; i < arraysize(kUnsafePortableBasenamesForWindows); ++i) {
     EXPECT_TRUE(IsReservedNameOnWindows(
         base::FilePath(kUnsafePortableBasenamesForWindows[i]).value()))
         << kUnsafePortableBasenamesForWindows[i];
   }
 }
 
 }  // namespace net