Mac: Elides the beginning of tab titles that have common prefixes

chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm

Index: chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
===================================================================
--- chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm	(revision 78685)
+++ chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -37,6 +37,7 @@
 #import "chrome/browser/ui/cocoa/tracking_area.h"
 #include "chrome/browser/ui/find_bar/find_bar.h"
 #include "chrome/browser/ui/find_bar/find_bar_controller.h"
+#include "chrome/browser/ui/title_prefix_matcher.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "content/browser/tab_contents/navigation_controller.h"
 #include "content/browser/tab_contents/navigation_entry.h"
@@ -143,6 +144,7 @@
             givesIndex:(NSInteger*)index
            disposition:(WindowOpenDisposition*)disposition;
 - (void)setNewTabButtonHoverState:(BOOL)showHover;
+- (void)updateCommonTitlePrefix;
 @end
 
 // A simple view class that prevents the Window Server from dragging the area
@@ -1023,6 +1025,8 @@
   // else.
   [self updateFaviconForContents:contents->tab_contents() atIndex:modelIndex];
 
+  [self updateCommonTitlePrefix];
+
   // Send a broadcast that the number of tabs have changed.
   [[NSNotificationCenter defaultCenter]
       postNotificationName:kTabStripNumberOfTabsChanged
@@ -1142,6 +1146,8 @@
 
   // Once we're totally done with the tab, delete its controller
   [tabArray_ removeObjectAtIndex:index];
+
+  [self updateCommonTitlePrefix];
 }
 
 // Called by the CAAnimation delegate when the tab completes the closing
@@ -1337,6 +1343,8 @@
   TabContentsController* updatedController =
       [tabContentsArray_ objectAtIndex:index];
   [updatedController tabDidChange:contents->tab_contents()];
+
+  [self updateCommonTitlePrefix];
 }
 
 // Called when a tab is moved (usually by drag&drop). Keep our parallel arrays
@@ -1388,6 +1396,8 @@
   // the tab has already been rendered, so re-layout the tabstrip. In all other
   // cases, the state is set before the tab is rendered so this isn't needed.
   [self layoutTabs];
+
+  [self updateCommonTitlePrefix];
 }
 
 - (void)setFrameOfSelectedTab:(NSRect)frame {
@@ -1906,4 +1916,38 @@
   }
 }
 
+// Update the lengths of common title prefixes for all tabs. This needs
+// to be done every time tabs are added/removed or when titles change.
+- (void)updateCommonTitlePrefix {
+  DCHECK_EQ([tabArray_ count], [tabArray_ count]);
+
+  std::vector<TitlePrefixMatcher::TitleInfo> tabTitleInfos;
+  ScopedVector<string16> titles;
+  size_t tabIndex;
+  size_t tabCount = [tabArray_ count];
+
+  // Add all tab titles to |tabTitleInfos|.
+  for (tabIndex = 0; tabIndex < tabCount; ++tabIndex) {
+    TabController* tabController = [tabArray_ objectAtIndex:tabIndex];
+    string16 title = base::SysNSStringToUTF16([tabController title]);
+    if (!title.empty() && ![tabController mini]) {
+      titles.push_back(new string16(title));
+      tabTitleInfos.push_back(TitlePrefixMatcher::TitleInfo(
+          titles[titles.size() - 1], tabIndex));
+    }
+  }
+
+  // Calculate the prefix length.
+  TitlePrefixMatcher::CalculatePrefixLengths(&tabTitleInfos);
+
+  // Update the prefix length for each tab.
+  for (size_t infoIndex = 0; infoIndex < tabTitleInfos.size(); ++infoIndex) {
+    tabIndex = tabTitleInfos[infoIndex].caller_value;
+    DCHECK(tabIndex < [tabArray_ count]);
+    TabController* tabController = [tabArray_ objectAtIndex:tabIndex];
+    [tabController setTitleCommonPrefixLength:
+        tabTitleInfos[infoIndex].prefix_length];
+  }
+}
+
 @end