// Copyright 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 CC_OUTPUT_OUTPUT_SURFACE_H_
#define CC_OUTPUT_OUTPUT_SURFACE_H_

#include <deque>

#include "base/basictypes.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/weak_ptr.h"
#include "cc/base/cc_export.h"
#include "cc/output/context_provider.h"
#include "cc/output/overlay_candidate_validator.h"
#include "cc/output/software_output_device.h"

namespace base { class SingleThreadTaskRunner; }

namespace ui { struct LatencyInfo; }

namespace gfx {
class Rect;
class Size;
class Transform;
}

namespace cc {

class CompositorFrame;
class CompositorFrameAck;
struct ManagedMemoryPolicy;
class OutputSurfaceClient;

// Represents the output surface for a compositor. The compositor owns
// and manages its destruction. Its lifetime is:
//   1. Created on the main thread by the LayerTreeHost through its client.
//   2. Passed to the compositor thread and bound to a client via BindToClient.
//      From here on, it will only be used on the compositor thread.
//   3. If the 3D context is lost, then the compositor will delete the output
//      surface (on the compositor thread) and go back to step 1.
class CC_EXPORT OutputSurface {
 public:
  enum {
    DEFAULT_MAX_FRAMES_PENDING = 2
  };

  OutputSurface(const scoped_refptr<ContextProvider>& context_provider,
                const scoped_refptr<ContextProvider>& worker_context_provider,
                scoped_ptr<SoftwareOutputDevice> software_device);
  OutputSurface(const scoped_refptr<ContextProvider>& context_provider,
                const scoped_refptr<ContextProvider>& worker_context_provider);
  explicit OutputSurface(
      const scoped_refptr<ContextProvider>& context_provider);

  explicit OutputSurface(scoped_ptr<SoftwareOutputDevice> software_device);

  OutputSurface(const scoped_refptr<ContextProvider>& context_provider,
                scoped_ptr<SoftwareOutputDevice> software_device);

  virtual ~OutputSurface();

  struct Capabilities {
    Capabilities()
        : delegated_rendering(false),
          max_frames_pending(0),
          draw_and_swap_full_viewport_every_frame(false),
          adjust_deadline_for_parent(true),
          uses_default_gl_framebuffer(true),
          flipped_output_surface(false),
          can_force_reclaim_resources(false),
          delegated_sync_points_required(true) {}
    bool delegated_rendering;
    int max_frames_pending;
    bool draw_and_swap_full_viewport_every_frame;
    // This doesn't handle the <webview> case, but once BeginFrame is
    // supported natively, we shouldn't need adjust_deadline_for_parent.
    bool adjust_deadline_for_parent;
    // Whether this output surface renders to the default OpenGL zero
    // framebuffer or to an offscreen framebuffer.
    bool uses_default_gl_framebuffer;
    // Whether this OutputSurface is flipped or not.
    bool flipped_output_surface;
    // Whether ForceReclaimResources can be called to reclaim all resources
    // from the OutputSurface.
    bool can_force_reclaim_resources;
    // True if sync points for resources are needed when swapping delegated
    // frames.
    bool delegated_sync_points_required;
  };

  const Capabilities& capabilities() const {
    return capabilities_;
  }

  virtual bool HasExternalStencilTest() const;

  // Obtain the 3d context or the software device associated with this output
  // surface. Either of these may return a null pointer, but not both.
  // In the event of a lost context, the entire output surface should be
  // recreated.
  ContextProvider* context_provider() const { return context_provider_.get(); }
  ContextProvider* worker_context_provider() const {
    return worker_context_provider_.get();
  }
  SoftwareOutputDevice* software_device() const {
    return software_device_.get();
  }

  // Called by the compositor on the compositor thread. This is a place where
  // thread-specific data for the output surface can be initialized, since from
  // this point on the output surface will only be used on the compositor
  // thread.
  virtual bool BindToClient(OutputSurfaceClient* client);

  virtual void EnsureBackbuffer();
  virtual void DiscardBackbuffer();

  virtual void Reshape(const gfx::Size& size, float scale_factor);
  virtual gfx::Size SurfaceSize() const;

  // If supported, this causes a ReclaimResources for all resources that are
  // currently in use.
  virtual void ForceReclaimResources() {}

  virtual void BindFramebuffer();

  // The implementation may destroy or steal the contents of the CompositorFrame
  // passed in (though it will not take ownership of the CompositorFrame
  // itself). For successful swaps, the implementation must call
  // OutputSurfaceClient::DidSwapBuffers() and eventually
  // DidSwapBuffersComplete().
  virtual void SwapBuffers(CompositorFrame* frame) = 0;
  virtual void OnSwapBuffersComplete();

  // Notifies frame-rate smoothness preference. If true, all non-critical
  // processing should be stopped, or lowered in priority.
  virtual void UpdateSmoothnessTakesPriority(bool prefer_smoothness) {}

  bool HasClient() { return !!client_; }

  // Get the class capable of informing cc of hardware overlay capability.
  virtual OverlayCandidateValidator* GetOverlayCandidateValidator() const;

  void DidLoseOutputSurface();
  void SetMemoryPolicy(const ManagedMemoryPolicy& policy);

  // Support for a pull-model where draws are requested by the output surface.
  //
  // OutputSurface::Invalidate is called by the compositor to notify that
  // there's new content.
  virtual void Invalidate() {}

  // Updates the worker context provider's visibility, freeing GPU resources if
  // appropriate.
  virtual void SetWorkerContextShouldAggressivelyFreeResources(bool is_visible);

 protected:
  OutputSurfaceClient* client_;

  void PostSwapBuffersComplete();

  struct OutputSurface::Capabilities capabilities_;
  scoped_refptr<ContextProvider> context_provider_;
  scoped_refptr<ContextProvider> worker_context_provider_;
  scoped_ptr<SoftwareOutputDevice> software_device_;
  gfx::Size surface_size_;
  float device_scale_factor_;

  void CommitVSyncParameters(base::TimeTicks timebase,
                             base::TimeDelta interval);

  void SetNeedsRedrawRect(const gfx::Rect& damage_rect);
  void ReclaimResources(const CompositorFrameAck* ack);
  void SetExternalStencilTest(bool enabled);
  void SetExternalDrawConstraints(
      const gfx::Transform& transform,
      const gfx::Rect& viewport,
      const gfx::Rect& clip,
      const gfx::Rect& viewport_rect_for_tile_priority,
      const gfx::Transform& transform_for_tile_priority,
      bool resourceless_software_draw);

 private:
  bool external_stencil_test_enabled_;

  base::WeakPtrFactory<OutputSurface> weak_ptr_factory_;

  DISALLOW_COPY_AND_ASSIGN(OutputSurface);
};

}  // namespace cc

#endif  // CC_OUTPUT_OUTPUT_SURFACE_H_