Enable/disable buttons when the corresponding command updates in the model.

Review URL: http://codereview.chromium.org/21128

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@9318 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 96 insertions, 2 deletions

diff --git a/chrome/browser/cocoa/tab_contents_controller.mm b/chrome/browser/cocoa/tab_contents_controller.mm
index 5ef5a4d..f31047a 100644
--- a/chrome/browser/cocoa/tab_contents_controller.mm
+++ b/chrome/browser/cocoa/tab_contents_controller.mm
@@ -4,11 +4,40 @@
 
 #include "chrome/browser/cocoa/tab_contents_controller.h"
 
+#import "chrome/app/chrome_dll_resource.h"
+#import "chrome/browser/command_updater.h"
+
+@interface TabContentsController(CommandUpdates)
+- (void)enabledStateChangedForCommand:(NSInteger)command enabled:(BOOL)enabled;
+@end
+
+// A C++ bridge class that handles listening for updates to commands and
+// passing them back to the controller.
+class TabContentsCommandObserver : public CommandUpdater::CommandObserver {
+ public:
+  TabContentsCommandObserver(TabContentsController* controller,
+                             CommandUpdater* commands);
+  ~TabContentsCommandObserver();
+
+  // Overridden from CommandUpdater::CommandObserver
+  void EnabledStateChangedForCommand(int command, bool enabled);
+
+ private:
+  TabContentsController* controller_;  // weak, owns us
+  CommandUpdater* commands_;  // weak
+};
+
+
 @implementation TabContentsController
 
-- (id)initWithNibName:(NSString*)name bundle:(NSBundle*)bundle {
+- (id)initWithNibName:(NSString*)name 
+               bundle:(NSBundle*)bundle
+             contents:(TabContents*)contents
+             commands:(CommandUpdater*)commands {
   if ((self = [super initWithNibName:name bundle:bundle])) {
-    // nothing to do
+    commands_ = commands;
+    if (commands_)
+      observer_ = new TabContentsCommandObserver(self, commands);
   }
   return self;
 }
@@ -16,6 +45,7 @@
 - (void)dealloc {
   // make sure our contents have been removed from the window
   [[self view] removeFromSuperview];
+  delete observer_;
   [super dealloc];
 }
 
@@ -23,6 +53,41 @@
   [locationBar_ setStringValue:@"http://dev.chromium.org"];
 }
 
+// Returns YES if the tab represented by this controller is the front-most.
+- (BOOL)isCurrentTab {
+  // We're the current tab if we're in the view hierarchy, otherwise some other
+  // tab is.
+  return [[self view] superview] ? YES : NO;
+}
+
+// Called when the state for a command changes to |enabled|. Update the
+// corresponding UI element.
+- (void)enabledStateChangedForCommand:(NSInteger)command enabled:(BOOL)enabled {
+  // We don't need to update anything if we're not the frontmost tab.
+  // TODO(pinkerton): i'm worried that observer ordering could cause the
+  // notification to be sent before we've been put into the view, but we
+  // appear to be called in the right order so far.
+  if (![self isCurrentTab])
+    return;
+
+  NSButton* button = nil;
+  switch (command) {
+    case IDC_BACK:
+    button = backButton_;
+    break;
+    case IDC_FORWARD:
+    button = forwardButton_;
+    break;
+    case IDC_HOME:
+    // TODO(pinkerton): add home button
+    break;
+    case IDC_STAR:
+    button = starButton_;
+    break;
+  }
+  [button setEnabled:enabled];
+}
+
 - (IBAction)fullScreen:(id)sender {
   if ([[self view] isInFullScreenMode]) {
     [[self view] exitFullScreenModeWithOptions:nil];
@@ -32,3 +97,32 @@
 }
 
 @end
+
+//--------------------------------------------------------------------------
+
+TabContentsCommandObserver::TabContentsCommandObserver(
+    TabContentsController* controller, CommandUpdater* commands)
+        : controller_(controller), commands_(commands) {
+  DCHECK(controller_ && commands);
+  // Register for notifications about state changes for the toolbar buttons
+  commands_->AddCommandObserver(IDC_BACK, this);
+  commands_->AddCommandObserver(IDC_FORWARD, this);
+  commands_->AddCommandObserver(IDC_RELOAD, this);
+  commands_->AddCommandObserver(IDC_HOME, this);
+  commands_->AddCommandObserver(IDC_STAR, this);
+}
+
+TabContentsCommandObserver::~TabContentsCommandObserver() {
+  // Unregister the notifications
+  commands_->RemoveCommandObserver(IDC_BACK, this);
+  commands_->RemoveCommandObserver(IDC_FORWARD, this);
+  commands_->RemoveCommandObserver(IDC_RELOAD, this);
+  commands_->RemoveCommandObserver(IDC_HOME, this);
+  commands_->RemoveCommandObserver(IDC_STAR, this);
+}
+
+void TabContentsCommandObserver::EnabledStateChangedForCommand(int command, 
+                                                               bool enabled) {
+  [controller_ enabledStateChangedForCommand:command 
+                                     enabled:enabled ? YES : NO];
+}