Add FilePath::FinalExtension() to avoid double extensions (.tar.gz) for file selector

ui/base/dialogs/select_file_dialog_mac.mm

 // Copyright (c) 2012 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 "ui/base/dialogs/select_file_dialog.h"
 
 #import <Cocoa/Cocoa.h>
 #include <CoreServices/CoreServices.h>
 
 #include <map>
@@ skipping 17 matching lines @@
 
 const int kFileTypePopupTag = 1234;
 
 CFStringRef CreateUTIFromExtension(const FilePath::StringType& ext) {
   base::mac::ScopedCFTypeRef<CFStringRef> ext_cf(
       base::SysUTF8ToCFStringRef(ext));
   return UTTypeCreatePreferredIdentifierForTag(
       kUTTagClassFilenameExtension, ext_cf.get(), NULL);
 }
 
+FilePath::StringType LastExtension(const FilePath::StringType& ext) {
+  size_t last_dot = ext.rfind('.');
+  if (last_dot == std::string::npos)
+    return ext;
+  return ext.substr(last_dot + 1);

[Avi (use Gerrit), 2012/11/13 20:41:00]

Isn't there something on FilePath that would do this?

[davidben, 2012/11/13 20:53:28]

There is FilePath::Extension() and friends, but it's the thing producing the
double-extensions in the first place. Maybe it shouldn't do that on OS X? That
would change a lot of things though.

http://code.google.com/p/chromium/source/search?q=kCommonDoubleExtensionSuffixes

+}
+
 }  // namespace
 
 class SelectFileDialogImpl;
 
 // A bridge class to act as the modal delegate to the save/open sheet and send
 // the results to the C++ class.
 @interface SelectFileDialogBridge : NSObject<NSOpenSavePanelDelegate> {
  @private
   SelectFileDialogImpl* selectFileDialogImpl_;  // WEAK; owns us
 }
@@ skipping 169 matching lines @@
       // it is not always the case that the given extensions in one of the sub-
       // lists are all synonyms. In fact, in the case of a <select> element with
       // multiple "accept" types, all the extensions allowed for all the types
       // will be part of one list. To be safe, allow the types of all the
       // specified extensions.
       NSMutableSet* file_type_set = [NSMutableSet set];
       for (size_t i = 0; i < file_types->extensions.size(); ++i) {
         const std::vector<FilePath::StringType>& ext_list =
             file_types->extensions[i];
         for (size_t j = 0; j < ext_list.size(); ++j) {
+          // NSSavePanel cannot handle extensions like tar.gz, so we

[Avi (use Gerrit), 2012/11/13 20:41:00]

It's not an NSSavePanel issue, but a UTI issue; a UTI cannot represent more than
one extension.

+          // remove all but the last component.
+          std::string ext = LastExtension(ext_list[j]);
           base::mac::ScopedCFTypeRef<CFStringRef> uti(
-              CreateUTIFromExtension(ext_list[j]));
+              CreateUTIFromExtension(ext));
           [file_type_set addObject:base::mac::CFToNSCast(uti.get())];
 
           // Always allow the extension itself, in case the UTI doesn't map
           // back to the original extension correctly. This occurs with dynamic
           // UTIs on 10.7 and 10.8.
           // See http://crbug.com/148840, http://openradar.me/12316273
           base::mac::ScopedCFTypeRef<CFStringRef> ext_cf(
-              base::SysUTF8ToCFStringRef(ext_list[j]));
+              base::SysUTF8ToCFStringRef(ext));
           [file_type_set addObject:base::mac::CFToNSCast(ext_cf.get())];
         }
       }
       allowed_file_types = [file_type_set allObjects];
     }
     if (type == SELECT_SAVEAS_FILE)
       [dialog setAllowedFileTypes:allowed_file_types];
     // else we'll pass it in when we run the open panel
 
     if (file_types->include_all_files || file_types->extensions.empty())
       [dialog setAllowsOtherFileTypes:YES];
 
     if (file_types->extension_description_overrides.size() > 1) {
       NSView* accessory_view = GetAccessoryView(file_types, file_type_index);
       [dialog setAccessoryView:accessory_view];
     }
   } else {
     // If no type info is specified, anything goes.
     [dialog setAllowsOtherFileTypes:YES];
   }
   hasMultipleFileTypeChoices_ =
       file_types ? file_types->extensions.size() > 1 : true;
 
   if (!default_extension.empty())
-    [dialog setAllowedFileTypes:@[base::SysUTF8ToNSString(default_extension)]];
+    [dialog setAllowedFileTypes:@[base::SysUTF8ToNSString(
+        LastExtension(default_extension))]];
 
   params_map_[dialog] = params;
   type_map_[dialog] = type;
 
   if (type == SELECT_SAVEAS_FILE) {
     [dialog setCanSelectHiddenExtension:YES];
   } else {
     NSOpenPanel* open_dialog = (NSOpenPanel*)dialog;
 
     if (type == SELECT_OPEN_MULTI_FILE)
@@ skipping 143 matching lines @@
 
 namespace ui {
 
 SelectFileDialog* CreateMacSelectFileDialog(
     SelectFileDialog::Listener* listener,
     SelectFilePolicy* policy) {
   return new SelectFileDialogImpl(listener, policy);
 }
 
 }  // namespace ui