ui/shell_dialogs/base_shell_dialog_win.h

   1 // Copyright (c) 2013 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 UI_SHELL_DIALOGS_BASE_SHELL_DIALOG_WIN_H_
   6 #define UI_SHELL_DIALOGS_BASE_SHELL_DIALOG_WIN_H_
   7
   8 #include <shlobj.h>
   9 #include <set>
  10
  11 #include "ui/shell_dialogs/base_shell_dialog.h"
  12 #include "ui/shell_dialogs/shell_dialogs_export.h"
  13
  14 namespace base {
  15 class Thread;
  16 }
  17
  18 namespace ui {
  19
  20 ///////////////////////////////////////////////////////////////////////////////
  21 // A base class for all shell dialog implementations that handles showing a
  22 // shell dialog modally on its own thread.
  23 class SHELL_DIALOGS_EXPORT BaseShellDialogImpl {
  24  public:
  25   BaseShellDialogImpl();
  26   virtual ~BaseShellDialogImpl();
  27
  28  protected:
  29   // Represents a run of a dialog.
  30   struct RunState {
  31     // Owning HWND, may be null.
  32     HWND owner;
  33
  34     // Thread dialog is run on.
  35     base::Thread* dialog_thread;
  36   };
  37
  38   // Called at the beginning of a modal dialog run. Disables the owner window
  39   // and tracks it. Returns the message loop of the thread that the dialog will
  40   // be run on.
  41   RunState BeginRun(HWND owner);
  42
  43   // Cleans up after a dialog run. If the run_state has a valid HWND this makes
  44   // sure that the window is enabled. This is essential because BeginRun
  45   // aggressively guards against multiple modal dialogs per HWND. Must be called
  46   // on the UI thread after the result of the dialog has been determined.
  47   //
  48   // In addition this deletes the Thread in RunState.
  49   void EndRun(RunState run_state);
  50
  51   // Returns true if a modal shell dialog is currently active for the specified
  52   // owner. Must be called on the UI thread.
  53   bool IsRunningDialogForOwner(HWND owner) const;
  54
  55   // Disables the window |owner|. Can be run from either the ui or the dialog
  56   // thread. Can be called on either the UI or the dialog thread. This function
  57   // is called on the dialog thread after the modal Windows Common dialog
  58   // functions return because Windows automatically re-enables the owning
  59   // window when those functions return, but we don't actually want them to be
  60   // re-enabled until the response of the dialog propagates back to the UI
  61   // thread, so we disable the owner manually after the Common dialog function
  62   // returns.
  63   void DisableOwner(HWND owner);
  64
  65  private:
  66   typedef std::set<HWND> Owners;
  67
  68   // Creates a thread to run a shell dialog on. Each dialog requires its own
  69   // thread otherwise in some situations where a singleton owns a single
  70   // instance of this object we can have a situation where a modal dialog in
  71   // one window blocks the appearance of a modal dialog in another.
  72   static base::Thread* CreateDialogThread();
  73
  74   // Enables the window |owner_|. Can only be run from the ui thread.
  75   void EnableOwner(HWND owner);
  76
  77   // A list of windows that currently own active shell dialogs for this
  78   // instance. For example, if the DownloadManager owns an instance of this
  79   // object and there are two browser windows open both with Save As dialog
  80   // boxes active, this list will consist of the two browser windows' HWNDs.
  81   // The derived class must call EndRun once the dialog is done showing to
  82   // remove the owning HWND from this list.
  83   // This object is static since it is maintained for all instances of this
  84   // object - i.e. you can't have two file pickers open for the
  85   // same owner, even though they might be represented by different instances
  86   // of this object.
  87   // This set only contains non-null HWNDs. NULL hwnds are not added to this
  88   // list.
  89   static Owners owners_;
  90   static int instance_count_;
  91
  92   DISALLOW_COPY_AND_ASSIGN(BaseShellDialogImpl);
  93 };
  94
  95 }  // namespace ui
  96
  97 #endif  // UI_SHELL_DIALOGS_BASE_SHELL_DIALOG_WIN_H_
  98