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// Copyright (c) 2012 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.
#ifndef UI_VIEWS_CONTROLS_MENU_MENU_RUNNER_H_
#define UI_VIEWS_CONTROLS_MENU_MENU_RUNNER_H_
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "ui/views/controls/menu/menu_item_view.h"
namespace views {
class MenuButton;
class Widget;
namespace internal {
class DisplayChangeListener;
class MenuRunnerImpl;
}
// MenuRunner is responsible for showing (running) the menu and additionally
// owning the MenuItemView. RunMenuAt() runs a nested message loop. It is safe
// to delete MenuRunner at any point, but MenuRunner internally only deletes the
// MenuItemView *after* the nested message loop completes. If MenuRunner is
// deleted while the menu is showing the delegate of the menu is reset. This is
// done to ensure delegates aren't notified after they may have been deleted.
//
// NOTE: while you can delete a MenuRunner at any point, the nested message loop
// won't return immediately. This means if you delete the object that owns
// the MenuRunner while the menu is running, your object is effectively still
// on the stack. A return value of MENU_DELETED indicated this. In most cases
// if RunMenuAt() returns MENU_DELETED, you should return immediately.
//
// Similarly you should avoid creating MenuRunner on the stack. Doing so means
// MenuRunner may not be immediately destroyed if your object is destroyed,
// resulting in possible callbacks to your now deleted object. Instead you
// should define MenuRunner as a scoped_ptr in your class so that when your
// object is destroyed MenuRunner initiates the proper cleanup and ensures your
// object isn't accessed again.
class VIEWS_EXPORT MenuRunner {
public:
enum RunTypes {
// The menu has mnemonics.
HAS_MNEMONICS = 1 << 0,
// The menu is a nested context menu. For example, click a folder on the
// bookmark bar, then right click an entry to get its context menu.
IS_NESTED = 1 << 1,
// Used for showing a menu during a drop operation. This does NOT block the
// caller, instead the delegate is notified when the menu closes via the
// DropMenuClosed method.
FOR_DROP = 1 << 2,
// The menu is a context menu (not necessarily nested), for example right
// click on a link on a website in the browser.
CONTEXT_MENU = 1 << 3,
};
enum RunResult {
// Indicates RunMenuAt is returning because the MenuRunner was deleted.
MENU_DELETED,
// Indicates RunMenuAt returned and MenuRunner was not deleted.
NORMAL_EXIT
};
// Creates a new MenuRunner. MenuRunner owns the supplied menu.
explicit MenuRunner(MenuItemView* menu);
~MenuRunner();
// Returns the menu.
MenuItemView* GetMenu();
// Takes ownership of |menu|, deleting it when MenuRunner is deleted. You
// only need call this if you create additional menus from
// MenuDelegate::GetSiblingMenu.
void OwnMenu(MenuItemView* menu);
// Runs the menu. |types| is a bitmask of RunTypes. If this returns
// MENU_DELETED the method is returning because the MenuRunner was deleted.
// Typically callers should NOT do any processing if this returns
// MENU_DELETED.
RunResult RunMenuAt(Widget* parent,
MenuButton* button,
const gfx::Rect& bounds,
MenuItemView::AnchorPosition anchor,
int32 types) WARN_UNUSED_RESULT;
// Returns true if we're in a nested message loop running the menu.
bool IsRunning() const;
// Hides and cancels the menu. This does nothing if the menu is not open.
void Cancel();
private:
internal::MenuRunnerImpl* holder_;
scoped_ptr<internal::DisplayChangeListener> display_change_listener_;
DISALLOW_COPY_AND_ASSIGN(MenuRunner);
};
namespace internal {
// DisplayChangeListener is intended to listen for changes in the display size
// and cancel the menu. DisplayChangeListener is created when the menu is
// shown.
class DisplayChangeListener {
public:
virtual ~DisplayChangeListener() {}
// Creates the platform specified DisplayChangeListener, or NULL if there
// isn't one. Caller owns the returned value.
static DisplayChangeListener* Create(Widget* parent,
MenuRunner* runner);
protected:
DisplayChangeListener() {}
};
}
} // namespace views
#endif // UI_VIEWS_CONTROLS_MENU_MENU_RUNNER_H_
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