// 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_COMPOSITOR_LAYER_OWNER_H_ #define UI_COMPOSITOR_LAYER_OWNER_H_ #include "base/compiler_specific.h" #include "base/memory/scoped_ptr.h" #include "ui/compositor/compositor_export.h" #include "ui/compositor/layer.h" namespace ui { class LayerOwnerDelegate; class COMPOSITOR_EXPORT LayerOwner { public: LayerOwner(); virtual ~LayerOwner(); void SetLayer(Layer* layer); // Releases the owning reference to its layer, and returns it. // This is used when you need to animate the presentation of the owner just // prior to destroying it. The Owner can be destroyed soon after calling this // function, and the caller is then responsible for disposing of the layer // once any animation completes. Note that layer() will remain valid until the // end of ~LayerOwner(). Layer* AcquireLayer() WARN_UNUSED_RESULT; // Asks the owner to recreate the layer, returning the old Layer. NULL is // returned if there is no existing layer, or recreate is not supported. // // This does not recurse. Existing children of the layer are moved to the new // layer. scoped_ptr<Layer> RecreateLayer(); ui::Layer* layer() { return layer_; } const ui::Layer* layer() const { return layer_; } void set_layer_owner_delegate(LayerOwnerDelegate* delegate) { layer_owner_delegate_ = delegate; } protected: void DestroyLayer(); bool OwnsLayer() const; private: // The LayerOwner owns its layer unless ownership is relinquished via a call // to AcquireLayer(). After that moment |layer_| will still be valid but // |layer_owner_| will be NULL. The reason for releasing ownership is that // the client may wish to animate the layer beyond the lifetime of the owner, // e.g. fading it out when it is destroyed. scoped_ptr<Layer> layer_owner_; Layer* layer_; LayerOwnerDelegate* layer_owner_delegate_; DISALLOW_COPY_AND_ASSIGN(LayerOwner); }; } // namespace ui #endif // UI_COMPOSITOR_LAYER_OWNER_H_