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      1 // Copyright (c) 2012 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 #ifndef CHROME_BROWSER_UI_APP_MODAL_DIALOGS_APP_MODAL_DIALOG_QUEUE_H_
      6 #define CHROME_BROWSER_UI_APP_MODAL_DIALOGS_APP_MODAL_DIALOG_QUEUE_H_
      7 
      8 #include <deque>
      9 
     10 #include "base/basictypes.h"
     11 
     12 class AppModalDialog;
     13 
     14 template <typename T> struct DefaultSingletonTraits;
     15 
     16 // Keeps a queue of AppModalDialogs, making sure only one app modal
     17 // dialog is shown at a time.
     18 // This class is a singleton.
     19 class AppModalDialogQueue {
     20  public:
     21   typedef std::deque<AppModalDialog*>::iterator iterator;
     22 
     23   // Returns the singleton instance.
     24   static AppModalDialogQueue* GetInstance();
     25 
     26   // Adds a modal dialog to the queue. If there are no other dialogs in the
     27   // queue, the dialog will be shown immediately. Once it is shown, the
     28   // most recently active browser window (or whichever is currently active)
     29   // will be app modal, meaning it will be activated if the user tries to
     30   // activate any other browser windows.
     31   // Note: The AppModalDialog |dialog| must be window modal before it
     32   // can be added as app modal.
     33   void AddDialog(AppModalDialog* dialog);
     34 
     35   // Removes the current dialog in the queue (the one that is being shown).
     36   // Shows the next dialog in the queue, if any is present. This does not
     37   // ensure that the currently showing dialog is closed, it just makes it no
     38   // longer app modal.
     39   void ShowNextDialog();
     40 
     41   // Activates and shows the current dialog, if the user clicks on one of the
     42   // windows disabled by the presence of an app modal dialog. This forces
     43   // the window to be visible on the display even if desktop manager software
     44   // opened the dialog on another virtual desktop. Assumes there is currently a
     45   // dialog being shown. (Call BrowserList::IsShowingAppModalDialog to test
     46   // this condition).
     47   void ActivateModalDialog();
     48 
     49   // Returns true if there is currently an active app modal dialog box.
     50   bool HasActiveDialog() const;
     51 
     52   AppModalDialog* active_dialog() { return active_dialog_; }
     53 
     54   // Iterators to walk the queue. The queue does not include the currently
     55   // active app modal dialog box.
     56   iterator begin() { return app_modal_dialog_queue_.begin(); }
     57   iterator end() { return app_modal_dialog_queue_.end(); }
     58 
     59  private:
     60   friend struct DefaultSingletonTraits<AppModalDialogQueue>;
     61 
     62   AppModalDialogQueue();
     63   ~AppModalDialogQueue();
     64 
     65   // Shows |dialog| and notifies the BrowserList that a modal dialog is showing.
     66   void ShowModalDialog(AppModalDialog* dialog);
     67 
     68   // Returns the next dialog to show. This removes entries from
     69   // app_modal_dialog_queue_ until one is valid or the queue is empty. This
     70   // returns NULL if there are no more dialogs, or all the dialogs in the queue
     71   // are not valid.
     72   AppModalDialog* GetNextDialog();
     73 
     74   // Contains all app modal dialogs which are waiting to be shown. The currently
     75   // active modal dialog is not included.
     76   std::deque<AppModalDialog*> app_modal_dialog_queue_;
     77 
     78   // The currently active app-modal dialog box's delegate. NULL if there is no
     79   // active app-modal dialog box.
     80   AppModalDialog* active_dialog_;
     81 
     82   // Stores if |ShowModalDialog()| is currently being called on an app-modal
     83   // dialog.
     84   bool showing_modal_dialog_;
     85 
     86   DISALLOW_COPY_AND_ASSIGN(AppModalDialogQueue);
     87 };
     88 
     89 #endif  // CHROME_BROWSER_UI_APP_MODAL_DIALOGS_APP_MODAL_DIALOG_QUEUE_H_
     90