Allow windows with a single tab to be merged into other windows with drag and...

chrome/browser/cocoa/tab_view.mm

 // Copyright (c) 2009 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 "chrome/browser/cocoa/tab_view.h"
+#import "chrome/browser/cocoa/tab_view.h"
 
+#include "base/logging.h"
 #include "chrome/browser/cocoa/nsimage_cache.h"
-#include "chrome/browser/cocoa/tab_controller.h"
-#include "chrome/browser/cocoa/tab_window_controller.h"
+#import "chrome/browser/cocoa/tab_controller.h"
+#import "chrome/browser/cocoa/tab_window_controller.h"
 
 // Constants for inset and control points for tab shape.
 static const CGFloat kInsetMultiplier = 2.0/3.0;
 static const CGFloat kControlPoint1Multiplier = 1.0/3.0;
 static const CGFloat kControlPoint2Multiplier = 3.0/8.0;
 
 static const NSTimeInterval kAnimationShowDuration = 0.2;
 static const NSTimeInterval kAnimationHideDuration = 0.4;
 
 @implementation TabView
@@ skipping 115 matching lines @@
 - (BOOL)canBeDragged {
   NSWindowController *controller = [sourceWindow_ windowController];
   if ([controller isKindOfClass:[TabWindowController class]]) {
     TabWindowController* realController =
         static_cast<TabWindowController*>(controller);
     return [realController isTabDraggable:self];
   }
   return YES;
 }
 
+// Find all the windows that could be a target. It has to be of the
+// appropriate class, and visible (obviously). Note that the window cannot be
+// a target for itself.
+- (NSArray*)dropTargetsForController:(TabWindowController*)dragController {
+  NSMutableArray* targets = [NSMutableArray array];
+  NSWindow* dragWindow = [dragController window];
+  for (NSWindow* window in [NSApp windows]) {
+    if (window == dragWindow) continue;
+    if (![window isVisible]) continue;
+    NSWindowController *controller = [window windowController];
+    if ([controller isKindOfClass:[TabWindowController class]]) {
+      TabWindowController* realController =
+          static_cast<TabWindowController*>(controller);
+      if ([realController canReceiveFrom:dragController]) {
+        [targets addObject:controller];
+      }
+    }
+  }
+  return targets;
+}
+
 // Handle clicks and drags in this button. We get here because we have
 // overridden acceptsFirstMouse: and the click is within our bounds.
 // TODO(pinkerton/alcor): This routine needs *a lot* of work to marry Cole's
 // ideas of dragging cocoa views between windows and how the Browser and
 // TabStrip models want to manage tabs.
 
 static const CGFloat kTearDistance = 36.0;
 static const NSTimeInterval kTearDuration = 0.333;
 
 // This is used to judge whether the mouse has moved during rapid closure; if it
@@ skipping 31 matching lines @@
   sourceTabFrame_ = [self frame];
   sourceController_ = [sourceWindow_ windowController];
   draggedController_ = nil;
   dragWindow_ = nil;
   dragOverlay_ = nil;
   targetController_ = nil;
   tabWasDragged_ = NO;
   tearTime_ = 0.0;
   draggingWithinTabStrip_ = YES;
 
-  // We don't want to "tear off" a tab if there's only one in the window. Treat
-  // it like we're dragging around a tab we've already detached. Note that
-  // unit tests might have |-numberOfTabs| reporting zero since the model
-  // won't be fully hooked up. We need to be prepared for that and not send
-  // them into the "magnetic" codepath.
+  // If there's more than one potential window to be a drop target, we want to
+  // treat a drag of a tab just like dragging around a tab that's already
+  // detached. Note that unit tests might have |-numberOfTabs| reporting zero
+  // since the model won't be fully hooked up. We need to be prepared for that
+  // and not send them into the "magnetic" codepath.
+  NSArray* targets = [self dropTargetsForController:sourceController_];
   moveWindowOnDrag_ =
-      [sourceController_ numberOfTabs] <= 1 || ![self canBeDragged];
+      ([sourceController_ numberOfTabs] < 2 && ![targets count]) ||
+          ![self canBeDragged];

[rohitrao (ping after 24h), 2009/09/10 19:03:56]

Should this be in line with the "(" above?

[pink (ping after 24hrs), 2009/09/10 19:05:55]

No, the first two should bind together, or'd with the last expression.

[pink (ping after 24hrs), 2009/09/10 19:06:31]

Oops, my bad, yes. Misunderstood.

+  // If we are dragging a tab, a window with a single tab should immediately
+  // snap off and not drag within the tab strip.
+  if (!moveWindowOnDrag_)
+    draggingWithinTabStrip_ = [sourceController_ numberOfTabs] > 1;
 
   dragOrigin_ = [NSEvent mouseLocation];
 
   // Because we move views between windows, we need to handle the event loop
   // ourselves. Ideally we should use the standard event loop.
   while (1) {
     theEvent =
     [NSApp nextEventMatchingMask:NSLeftMouseUpMask | NSLeftMouseDraggedMask
                        untilDate:[NSDate distantFuture]
                           inMode:NSDefaultRunLoopMode dequeue:YES];
@@ skipping 66 matching lines @@
     } else {
       return;
     }
   }
 
   NSPoint lastPoint =
     [[theEvent window] convertBaseToScreen:[theEvent locationInWindow]];
 
   // Do not start dragging until the user has "torn" the tab off by
   // moving more than 3 pixels.
-  NSDate* targetDwellDate = nil; // The date this target was first chosen
-  NSMutableArray* targets = [NSMutableArray array];
+  NSDate* targetDwellDate = nil;  // The date this target was first chosen.
 
   NSPoint thisPoint = [NSEvent mouseLocation];
 
-  // Find all the windows that could be a target. It has to be of the
-  // appropriate class, and visible (obviously).
-  if (![targets count]) {
-    for (NSWindow* window in [NSApp windows]) {
-      if (window == dragWindow_) continue;
-      if (![window isVisible]) continue;
-      NSWindowController *controller = [window windowController];
-      if ([controller isKindOfClass:[TabWindowController class]]) {
-        TabWindowController* realController =
-            static_cast<TabWindowController*>(controller);
-        if ([realController canReceiveFrom:sourceController_]) {
-          [targets addObject:controller];
-        }
-      }
-    }
-  }
-
   // Iterate over possible targets checking for the one the mouse is in.
   // The mouse can be in either the tab or window frame.
+  NSArray* targets = [self dropTargetsForController:draggedController_];
   TabWindowController* newTarget = nil;
   for (TabWindowController* target in targets) {
     NSRect windowFrame = [[target window] frame];
     if (NSPointInRect(thisPoint, windowFrame)) {
       NSRect tabStripFrame = [[target tabStripView] frame];
       tabStripFrame.origin = [[target window]
                               convertBaseToScreen:tabStripFrame.origin];
       if (NSPointInRect(thisPoint, tabStripFrame)) {
         newTarget = target;
       }
       break;
     }
   }
 
   // If we're now targeting a new window, re-layout the tabs in the old
   // target and reset how long we've been hovering over this new one.
   if (targetController_ != newTarget) {
     targetDwellDate = [NSDate date];
     [targetController_ removePlaceholder];
     targetController_ = newTarget;
     if (!newTarget) {
       tearTime_ = [NSDate timeIntervalSinceReferenceDate];
       tearOrigin_ = [dragWindow_ frame].origin;
     }
   }
 
   // Create or identify the dragged controller.
   if (!draggedController_) {
-    // Detach from the current window and put it in a new window.
+    // Detach from the current window and put it in a new window. If there are
+    // no more tabs remaining after detaching, the source window is about to
+    // go away (it's been autoreleased) so we need to ensure we don't reference
+    // it any more. In that case the new controller becomes our source
+    // controller.
     draggedController_ = [sourceController_ detachTabToNewWindow:self];
     dragWindow_ = [draggedController_ window];
     [dragWindow_ setAlphaValue:0.0];
+    if (![sourceController_ numberOfTabs]) {
+      sourceController_ = draggedController_;
+      sourceWindow_ = dragWindow_;
+    }
 
     // If dragging the tab only moves the current window, do not show overlay
     // so that sheets stay on top of the window.
     // Bring the target window to the front and make sure it has a border.
     [dragWindow_ setLevel:NSFloatingWindowLevel];
     [dragWindow_ orderFront:nil];
     [dragWindow_ makeMainWindow];
     [draggedController_ showOverlay];
     dragOverlay_ = [draggedController_ overlayWindow];
     // Force the new tab button to be hidden. We'll reset it on mouse up.
@@ skipping 36 matching lines @@
   }
   [dragWindow_ setFrameOrigin:NSMakePoint(origin.x, origin.y)];
 
   // If we're not hovering over any window, make the window is fully
   // opaque. Otherwise, find where the tab might be dropped and insert
   // a placeholder so it appears like it's part of that window.
   if (targetController_) {
     if (![[targetController_ window] isKeyWindow]) {
       // && ([targetDwellDate timeIntervalSinceNow] < -REQUIRED_DWELL)) {
       [[targetController_ window] orderFront:nil];
-      [targets removeAllObjects];

[rohitrao (ping after 24h), 2009/09/10 19:03:56]

This is ok to delete because targets is never referenced again?

[pink (ping after 24hrs), 2009/09/10 19:05:55]

Correct. It must have been leftover from something else.

       targetDwellDate = nil;
     }
 
     // Compute where placeholder should go and insert it into the
     // destination tab strip.
     NSRect dropTabFrame = [[targetController_ tabStripView] frame];
     TabView *draggedTabView = (TabView *)[draggedController_ selectedTabView];
     NSRect tabFrame = [draggedTabView frame];
     tabFrame.origin = [dragWindow_ convertBaseToScreen:tabFrame.origin];
     tabFrame.origin = [[targetController_ window]
@@ skipping 39 matching lines @@
     return;
 
   // We are now free to re-display the new tab button in the window we're
   // dragging. It will show when the next call to -layoutTabs (which happens
   // indrectly by several of the calls below, such as removing the placeholder).
   [draggedController_ showNewTabButton:YES];
 
   if (draggingWithinTabStrip_) {
     if (tabWasDragged_) {
       // Move tab to new location.
+      DCHECK([sourceController_ numberOfTabs]);
       TabWindowController* dropController = sourceController_;
       [dropController moveTabView:[dropController selectedTabView]
                    fromController:nil];
     }
   } else if (targetController_) {
     // Move between windows. If |targetController_| is nil, we're not dropping
     // into any existing window.
     NSView* draggedTabView = [draggedController_ selectedTabView];
     [draggedController_ removeOverlay];
     [targetController_ moveTabView:draggedTabView
@@ skipping 181 matching lines @@
   [[NSGraphicsContext currentContext] restoreGraphicsState];
 }
 
 // Called when the user hits the right mouse button (or control-clicks) to
 // show a context menu.
 - (void)rightMouseDown:(NSEvent*)theEvent {
   [NSMenu popUpContextMenu:[self menu] withEvent:theEvent forView:self];
 }
 
 @end