Drag and drop of buttons/folders from bar to bar.

Does not include DnD to/from menus.
No animations of drop destination yet.

BUG=http://crbug.com/17608

TEST=Do some draggin and droppin.
Confirm click still works on the marks and folders.
Confirm "other bookmarks" canNOT be moved.
Confirm NTP / detached bar also works for DnD.

Review URL: http://codereview.chromium.org/395031

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@32341 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 130 insertions, 0 deletions

diff --git a/chrome/browser/cocoa/bookmark_button.mm b/chrome/browser/cocoa/bookmark_button.mm
new file mode 100644
index 0000000..8ef0682
--- /dev/null
+++ b/chrome/browser/cocoa/bookmark_button.mm
@@ -0,0 +1,130 @@
+// 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.
+
+#import "base/scoped_nsobject.h"
+#import "chrome/browser/cocoa/bookmark_button.h"
+
+NSString* kBookmarkButtonDragType = @"ChromiumBookmarkButtonDragType";
+
+// http://codereview.chromium.org/180036/diff/3001/3004
+namespace {
+const CGFloat kWebDragStartHysteresisX = 5.0;
+const CGFloat kWebDragStartHysteresisY = 5.0;
+}
+
+@implementation BookmarkButton
+
+@synthesize draggable = draggable_;
+
+- (id)initWithFrame:(NSRect)frame {
+  if ((self = [super initWithFrame:frame])) {
+    draggable_ = YES;
+  }
+  return self;
+}
+
+// By default, NSButton ignores middle-clicks.
+- (void)otherMouseUp:(NSEvent*)event {
+  [self performClick:self];
+}
+
+- (void)beginDrag:(NSEvent*)event {
+  NSSize dragOffset = NSMakeSize(0.0, 0.0);
+  NSPasteboard* pboard = [NSPasteboard pasteboardWithName:NSDragPboard];
+  [pboard declareTypes:[NSArray arrayWithObject:kBookmarkButtonDragType]
+                 owner:self];
+
+  // This NSData is no longer referenced once the function ends so
+  // there is no need to retain/release when placing in here as an
+  // opaque pointer.
+  [pboard setData:[NSData dataWithBytes:&self length:sizeof(self)]
+          forType:kBookmarkButtonDragType];
+
+  // This won't work if the source view is clipped.  Fortunately, we
+  // don't display clipped bookmark buttons.
+  [[self superview] lockFocus];
+  scoped_nsobject<NSBitmapImageRep>
+      bitmapImage([[NSBitmapImageRep alloc]
+                    initWithFocusedViewRect:[self frame]]);
+
+  [[self superview] unlockFocus];
+  scoped_nsobject<NSImage> imageDrag([[NSImage alloc]
+                                       initWithSize:[bitmapImage size]]);
+  [imageDrag addRepresentation:bitmapImage];
+
+  // At the moment, moving bookmarks causes their buttons (like me!)
+  // to be destroyed and rebuilt.  Make sure we don't go away while on
+  // the stack.
+  [self retain];
+
+  CGFloat yAt = [self bounds].size.height;
+  [self dragImage:imageDrag at:NSMakePoint(0, yAt) offset:dragOffset
+            event:event pasteboard:pboard source:self slideBack:YES];
+
+  // And we're done.
+  [self autorelease];
+}
+
+- (void)draggedImage:(NSImage*)anImage
+             endedAt:(NSPoint)aPoint
+           operation:(NSDragOperation)operation {
+  beingDragged_ = NO;
+  [[self cell] setHighlighted:NO];
+}
+
+- (NSDragOperation)draggingSourceOperationMaskForLocal:(BOOL)isLocal {
+  return isLocal ? NSDragOperationMove : NSDragOperationNone;
+}
+
+- (void)mouseUp:(NSEvent*)theEvent {
+  // This conditional is never true (DnD loops in Cocoa eat the mouse
+  // up) but I added it in case future versions of Cocoa do unexpected
+  // things.
+  if (beingDragged_)
+    return [super mouseUp:theEvent];
+
+  // There are non-drag cases where a mouseUp: may happen
+  // (e.g. mouse-down, cmd-tab to another application, move mouse,
+  // mouse-up).  So we check.
+  NSPoint viewLocal = [self convertPoint:[theEvent locationInWindow]
+                                fromView:[[self window] contentView]];
+  if (NSPointInRect(viewLocal, [self bounds])) {
+    [self performClick:self];
+  } else {
+    [[self cell] setHighlighted:NO];
+  }
+}
+
+// Mimic "begin a click" operation visually.  Do NOT follow through
+// with normal button event handling.
+- (void)mouseDown:(NSEvent*)theEvent {
+  [[self cell] setHighlighted:YES];
+  initialMouseDownLocation_ = [theEvent locationInWindow];
+}
+
+// Return YES if we have crossed a threshold of movement after
+// mouse-down when we should begin a drag.  Else NO.
+- (BOOL)hasCrossedDragThreshold:(NSEvent*)theEvent {
+  NSPoint currentLocation = [theEvent locationInWindow];
+  if ((abs(currentLocation.x - initialMouseDownLocation_.x) >
+       kWebDragStartHysteresisX) ||
+      (abs(currentLocation.y - initialMouseDownLocation_.y) >
+       kWebDragStartHysteresisY)) {
+    return YES;
+  } else {
+    return NO;
+  }
+}
+
+- (void)mouseDragged:(NSEvent*)theEvent {
+  if (beingDragged_)
+    [super mouseDragged:theEvent];
+  else {
+    if (draggable_ && [self hasCrossedDragThreshold:theEvent]) {
+      [self beginDrag:theEvent];
+    }
+  }
+}
+
+@end