Mac: Fix tab view accessibility.

chrome/browser/ui/cocoa/tabs/tab_strip_view.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.
 
 #import "chrome/browser/ui/cocoa/tabs/tab_strip_view.h"
 
 #include <cmath>  // floor
 
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
@@ skipping 209 matching lines @@
 
 // (URLDropTarget protocol)
 - (BOOL)performDragOperation:(id<NSDraggingInfo>)sender {
   return [dropHandler_ performDragOperation:sender];
 }
 
 - (BOOL)accessibilityIsIgnored {
   return NO;
 }
 
+// Returns AX children (tabs and new tab button), sorted from left to right.
+- (NSArray*)accessibilityChildren {
+  NSArray* children =
+      [super accessibilityAttributeValue:NSAccessibilityChildrenAttribute];

[Avi (use Gerrit), 2014/09/23 20:44:21]

Oh, yikes, was it really returning them in Z order? :(

+  return [children sortedArrayUsingComparator:
+      ^NSComparisonResult(id first, id second) {
+          NSPoint firstPosition =
+              [[first accessibilityAttributeValue:
+                          NSAccessibilityPositionAttribute] pointValue];
+          NSPoint secondPosition =
+              [[second accessibilityAttributeValue:
+                           NSAccessibilityPositionAttribute] pointValue];
+          if (firstPosition.x < secondPosition.x)
+            return NSOrderedAscending;
+          else if (firstPosition.x > secondPosition.x)
+            return NSOrderedDescending;
+          else
+            return NSOrderedSame;
+      }];
+}
+
 - (id)accessibilityAttributeValue:(NSString*)attribute {
-  if ([attribute isEqual:NSAccessibilityRoleAttribute])
+  if ([attribute isEqual:NSAccessibilityRoleAttribute]) {
     return NSAccessibilityTabGroupRole;
-  if ([attribute isEqual:NSAccessibilityTabsAttribute]) {
-    NSMutableArray* tabs = [[[NSMutableArray alloc] init] autorelease];
-    NSArray* children =
-        [self accessibilityAttributeValue:NSAccessibilityChildrenAttribute];
+  } else if ([attribute isEqual:NSAccessibilityChildrenAttribute]) {
+    return [self accessibilityChildren];
+  } else if ([attribute isEqual:NSAccessibilityTabsAttribute]) {
+    NSArray* children = [self accessibilityChildren];
+    NSMutableArray* tabs = [NSMutableArray arrayWithCapacity:[children count]];
     for (id child in children) {
       if ([[child accessibilityAttributeValue:NSAccessibilityRoleAttribute]
           isEqual:NSAccessibilityRadioButtonRole]) {
         [tabs addObject:child];
       }
     }
     return tabs;

[Avi (use Gerrit), 2014/09/23 20:44:20]

If you're already introducing blocks code, you could do

NSIndexSet* indexes = [children indexesOfObjectsPassingTest:^(...){ return
attribute isEqual:buttonRole}];
return [children objectsAtIndexes:indexes];

which is a bit cleaner.

[Andre, 2014/09/23 21:41:55]

Done.
I love programming with higher order functions in place of loops.
In my previous job, I made utilities to make these things even neater.
Something like:
  return Filter(children, ^BOOL(id child) {
      ...
  });

In this case, it would have reduced #lines by 4 instead of by 2.

The filter function takes id<NSFastEnumeration> as argument, so it works with
arrays, sets and dictionaries.
Same with Map, Reduce, Reject, Find, Any.
Maybe we can add these to chromium someday?
I look forward to the day I can program in Swift :-D

[Avi (use Gerrit), 2014/09/23 23:24:54]

I was honestly shocked that Apple didn't already have a block equivalent to
-[NSArray filteredArrayUsingPredicate:]...

+  } else if ([attribute isEqual:NSAccessibilityContentsAttribute]) {
+    return [self accessibilityChildren];
+  } else if ([attribute isEqual:NSAccessibilityValueAttribute]) {
+    return [controller_ activeTabView];
   }
-  if ([attribute isEqual:NSAccessibilityContentsAttribute])
-    return [self accessibilityAttributeValue:NSAccessibilityChildrenAttribute];
-  if ([attribute isEqual:NSAccessibilityValueAttribute])
-    return [controller_ activeTabView];
 
   return [super accessibilityAttributeValue:attribute];
 }
 
 - (NSArray*)accessibilityAttributeNames {
   NSMutableArray* attributes =
       [[super accessibilityAttributeNames] mutableCopy];
   [attributes addObject:NSAccessibilityTabsAttribute];
   [attributes addObject:NSAccessibilityContentsAttribute];
   [attributes addObject:NSAccessibilityValueAttribute];
@@ skipping 11 matching lines @@
 
 - (void)setNewTabButton:(NewTabButton*)button {
   newTabButton_.reset([button retain]);
 }
 
 - (void)setController:(TabStripController*)controller {
   controller_ = controller;
 }
 
 @end