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      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/memory/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   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
     79