chrome/browser/ui/cocoa/bookmarks/bookmark_bar_folder_hover_state.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #import <Cocoa/Cocoa.h>
   6
   7 #include "base/mac/scoped_nsobject.h"
   8 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_button.h"
   9
  10 // Hover state machine.  Encapsulates the hover state for
  11 // BookmarkBarFolderController.
  12 // A strict call order is implied with these calls.  It is ONLY valid to make
  13 // the following state transitions:
  14 // From:            To:               Via:
  15 // closed           opening           scheduleOpen...:
  16 // opening          closed            cancelPendingOpen...: or
  17 //                  open              scheduleOpen...: completes.
  18 // open             closing           scheduleClose...:
  19 // closing          open              cancelPendingClose...: or
  20 //                  closed            scheduleClose...: completes.
  21 //
  22 @interface BookmarkBarFolderHoverState : NSObject {
  23  @private
  24   // Enumeration of the valid states that the |hoverButton_| member can be in.
  25   // Because the opening and closing of hover views can be done asyncronously
  26   // there are periods where the hover state is in transtion between open and
  27   // closed.  During those times of transition the opening or closing operation
  28   // can be cancelled.  We serialize the opening and closing of the
  29   // |hoverButton_| using this state information.  This serialization is to
  30   // avoid race conditions where one hover button is being opened while another
  31   // is closing.
  32   enum HoverState {
  33     kHoverStateClosed = 0,
  34     kHoverStateOpening = 1,
  35     kHoverStateOpen = 2,
  36     kHoverStateClosing = 3
  37   };
  38
  39   // Like normal menus, hovering over a folder button causes it to
  40   // open.  This variable is set when a hover is initiated (but has
  41   // not necessarily fired yet).
  42   base::scoped_nsobject<BookmarkButton> hoverButton_;
  43
  44   // We model hover state as a state machine with specific allowable
  45   // transitions.  |hoverState_| is the state of this machine at any
  46   // given time.
  47   HoverState hoverState_;
  48 }
  49
  50 // Designated initializer.
  51 - (id)init;
  52
  53 // The BookmarkBarFolderHoverState decides when it is appropriate to hide
  54 // and show the button that the BookmarkBarFolderController drags over.
  55 - (NSDragOperation)draggingEnteredButton:(BookmarkButton*)button;
  56
  57 // The BookmarkBarFolderHoverState decides the fate of the hover button
  58 // when the BookmarkBarFolderController's view is exited.
  59 - (void)draggingExited;
  60
  61 @end
  62
  63 // Exposing these for unit testing purposes.  They are used privately in the
  64 // implementation as well.
  65 @interface BookmarkBarFolderHoverState(PrivateAPI)
  66 // State change APIs.
  67 - (void)scheduleCloseBookmarkFolderOnHoverButton;
  68 - (void)cancelPendingCloseBookmarkFolderOnHoverButton;
  69 - (void)scheduleOpenBookmarkFolderOnHoverButton:(BookmarkButton*)hoverButton;
  70 - (void)cancelPendingOpenBookmarkFolderOnHoverButton;
  71 @end
  72
  73 // Exposing these for unit testing purposes.  They are used only in tests.
  74 @interface BookmarkBarFolderHoverState(TestingAPI)
  75 // Accessors and setters for button and hover state.
  76 - (BookmarkButton*)hoverButton;
  77 - (HoverState)hoverState;
  78 @end