Implement dropping of tabs into an existing tab strip from another window.

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"
 #include "chrome/browser/cocoa/tab_window_controller.h"
 
 @implementation TabView
 
 - (id)initWithFrame:(NSRect)frame {
@@ skipping 52 matching lines @@
   TabWindowController* sourceController = [sourceWindow windowController];
 
   // 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.
   BOOL isLastRemainingTab = [sourceController numberOfTabs] <= 1;
 
   BOOL dragging = YES;
-  BOOL moved = NO;
+  BOOL moveBetweenWindows = NO;
 
   NSPoint lastPoint =
     [[theEvent window] convertBaseToScreen:[theEvent locationInWindow]];
 
   // First, go through the magnetic drag cycle. We break out of this if
   // "stretchiness" ever exceeds the a set amount.
   NSRect frame = [self frame];
   if (!isLastRemainingTab) {
     while (dragging) {
       theEvent =
@@ skipping 12 matching lines @@
       CGFloat tearForce = fabs(thisPoint.y - lastPoint.y);
       if (tearForce > kTearDistance) break;
       if ([theEvent type] == NSLeftMouseUp) {
         // Mouse up, break out of the drag event tracking loop
         dragging = NO;
         break;
       }
     }
   }
 
-  [sourceController removePlaceholder];
+  if (dragging)
+    [sourceController removePlaceholder];
 
   TabWindowController* draggedController = nil;
   TabWindowController* targetController = nil;
 
   NSWindow* dragWindow = nil;
   NSWindow* dragOverlay = nil;
 
   // Do not start dragging until the user has "torn" the tab off by
   // moving more than 3 pixels.
   BOOL torn = NO;
@@ skipping 54 matching lines @@
     // 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;
     }
 
     NSEventType type = [theEvent type];
     if (type == NSLeftMouseDragged) {
-      moved = YES;
+      moveBetweenWindows = YES;
       if (!draggedController) {
         if (isLastRemainingTab) {
           draggedController = sourceController;
           dragWindow = [draggedController window];
         } else {
           // Detach from the current window and put it in a new window.
           draggedController = [sourceController detachTabToNewWindow:self];
           dragWindow = [draggedController window];
           [dragWindow setAlphaValue:0.0];
         }
@@ skipping 58 matching lines @@
        setAlphaValue:targetController ? 0.85 : 1.0];
     } else if (type == NSLeftMouseUp) {
       // Mouse up, break out of the drag event tracking loop
       dragging = NO;
     }
     lastPoint = thisPoint;
   }  // while tracking mouse
 
   // The drag/click is done. If the user dragged the mouse, finalize the drag
   // and clean up.
-  if (moved) {
-    TabWindowController *dropController = targetController;
-#if 1
-    dropController = nil; // Don't allow drops on other windows for now
-#endif
+  if (moveBetweenWindows) {
+    // Move between windows. If |targetController| is nil, we're not dropping
+    // into any existing window.
+    TabWindowController* dropController = targetController;
     if (dropController) {
-      // TODO(alcor/pinkerton): hookup drops on existing windows
-      NSRect adjustedFrame = [self bounds];
-      NSRect dropTabFrame =  [[dropController tabStripView] frame];
-      adjustedFrame.origin = [self convertPointToBase:NSZeroPoint];
-      adjustedFrame.origin =
-      [sourceWindow convertBaseToScreen:adjustedFrame.origin];
-      adjustedFrame.origin.x = adjustedFrame.origin.x - dropTabFrame.origin.x;
-      //adjustedFrame.origin.y = adjustedFrame.origin.y - dropTabFrame.origin.y;
-      //adjustedFrame.size.height += adjustedFrame.origin.y;
-      adjustedFrame.origin.y = 0;
-      // TODO(alcor): get add tab stuff working
-      // [dropController addTab:tab_];
-      [self setFrame:adjustedFrame];
-      [dropController layoutTabs];
-      [draggedController close];
+      // The ordering here is important. We need to be able to get from the
+      // TabView in the |draggedController| to whatever is needed by the tab
+      // model. To do so, it still has to be in the model, so we have to call
+      // "drop" before we call "detach".
+      NSView* draggedTabView = [draggedController selectedTabView];
+      [draggedController removeOverlay];
+      [dropController dropTabView:draggedTabView
+                   fromController:draggedController];
+      [draggedController detachTabView:draggedTabView];
       [dropController showWindow:nil];
     } else {
       [targetController removePlaceholder];
       [[dragWindow animator] setAlphaValue:1.0];
       [dragOverlay setHasShadow:NO];
       [dragWindow setHasShadow:YES];
       [draggedController removeOverlay];
       [dragWindow makeKeyAndOrderFront:nil];
 
       [[draggedController window] setLevel:NSNormalWindowLevel];
       [draggedController layoutTabs];
     }
     [sourceController layoutTabs];
+  } else {
+    // Move or click within a window. We need to differentiate between a
+    // click on the tab and a drag by checking against the initial x position.
+    NSPoint currentPoint = [NSEvent mouseLocation];
+    BOOL wasDrag = fabs(currentPoint.x - lastPoint.x) > kDragStartDistance;
+    if (wasDrag) {
+      // Move tab to new location.
+      TabWindowController* dropController = sourceController;
+      [dropController dropTabView:[dropController selectedTabView]
+                   fromController:nil];
+    }
   }
+
+  [sourceController removePlaceholder];
 }
 
 @end