/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim:set ts=2 sw=2 sts=2 et cindent: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef MOZILLA_DOM_OFFSCREENCANVAS_H_

#define MOZILLA_DOM_OFFSCREENCANVAS_H_

#include "gfxTypes.h"

#include "mozilla/DOMEventTargetHelper.h"

#include "mozilla/dom/DOMPrefs.h"

#include "mozilla/layers/LayersTypes.h"

#include "mozilla/RefPtr.h"

#include "CanvasRenderingContextHelper.h"

#include "nsCycleCollectionParticipant.h"

struct JSContext;

namespace mozilla {

class ErrorResult;

namespace layers {

class AsyncCanvasRenderer;

class CanvasClient;

} // namespace layers

namespace dom {

class Blob;

class ImageBitmap;

// This is helper class for transferring OffscreenCanvas to worker thread.

// Because OffscreenCanvas is not thread-safe. So we cannot pass Offscreen-

// Canvas to worker thread directly. Thus, we create this helper class and

// store necessary data in it then pass it to worker thread.

struct OffscreenCanvasCloneData final

{

  OffscreenCanvasCloneData(layers::AsyncCanvasRenderer* aRenderer,

                           uint32_t aWidth, uint32_t aHeight,

                           layers::LayersBackend aCompositorBackend,

                           bool aNeutered, bool aIsWriteOnly);

  ~OffscreenCanvasCloneData();

  RefPtr<layers::AsyncCanvasRenderer> mRenderer;

  uint32_t mWidth;

  uint32_t mHeight;

  layers::LayersBackend mCompositorBackendType;

  bool mNeutered;

  bool mIsWriteOnly;

};

class OffscreenCanvas final : public DOMEventTargetHelper

                            , public CanvasRenderingContextHelper

{

public:

  NS_DECL_ISUPPORTS_INHERITED

  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(OffscreenCanvas, DOMEventTargetHelper)

  OffscreenCanvas(nsIGlobalObject* aGlobal,

                  uint32_t aWidth,

                  uint32_t aHeight,

                  layers::LayersBackend aCompositorBackend,

                  layers::AsyncCanvasRenderer* aRenderer);

  nsCOMPtr<nsIGlobalObject> GetParentObject() const { return GetOwnerGlobal(); }

  virtual JSObject* WrapObject(JSContext* aCx,

                               JS::Handle<JSObject*> aGivenProto) override;

  static already_AddRefed<OffscreenCanvas>

  Constructor(const GlobalObject& aGlobal,

              uint32_t aWidth,

              uint32_t aHeight,

              ErrorResult& aRv);

  void ClearResources();

  uint32_t Width() const

  {

    return mWidth;

  }

  uint32_t Height() const

  {

    return mHeight;

  }

  void SetWidth(uint32_t aWidth, ErrorResult& aRv)

  {

    if (mNeutered) {

      aRv.Throw(NS_ERROR_FAILURE);

      return;

    }

    if (mWidth != aWidth) {

      mWidth = aWidth;

      CanvasAttrChanged();

    }

  }

  void SetHeight(uint32_t aHeight, ErrorResult& aRv)

  {

    if (mNeutered) {

      aRv.Throw(NS_ERROR_FAILURE);

      return;

    }

    if (mHeight != aHeight) {

      mHeight = aHeight;

      CanvasAttrChanged();

    }

  }

  already_AddRefed<ImageBitmap>

  TransferToImageBitmap(ErrorResult& aRv);

  already_AddRefed<Promise>

  ToBlob(JSContext* aCx,

         const nsAString& aType,

         JS::Handle<JS::Value> aParams,

         ErrorResult& aRv);

  nsICanvasRenderingContextInternal* GetContext() const

  {

    return mCurrentContext;

  }

  already_AddRefed<gfx::SourceSurface> GetSurfaceSnapshot(gfxAlphaType* aOutAlphaType = nullptr);

  static already_AddRefed<OffscreenCanvas>

  CreateFromCloneData(nsIGlobalObject* aGlobal, OffscreenCanvasCloneData* aData);

  // Return true on main-thread, and return gfx.offscreencanvas.enabled

  // on worker thread.

  static bool PrefEnabledOnWorkerThread(JSContext* aCx, JSObject* aObj);

  OffscreenCanvasCloneData* ToCloneData();

  void CommitFrameToCompositor();

  virtual bool GetOpaqueAttr() override

  {

    return false;

  }

  virtual nsIntSize GetWidthHeight() override

  {

    return nsIntSize(mWidth, mHeight);

  }

  virtual already_AddRefed<nsICanvasRenderingContextInternal>

  CreateContext(CanvasContextType aContextType) override;

  virtual already_AddRefed<nsISupports>

  GetContext(JSContext* aCx,

             const nsAString& aContextId,

             JS::Handle<JS::Value> aContextOptions,

             ErrorResult& aRv) override;

  void SetNeutered()

  {

    mNeutered = true;

  }

  bool IsNeutered() const

  {

    return mNeutered;

  }

  void SetWriteOnly()

  {

    mIsWriteOnly = true;

  }

  bool IsWriteOnly() const

  {

    return mIsWriteOnly;

  }

  layers::LayersBackend GetCompositorBackendType() const

  {

    return mCompositorBackendType;

  }

private:

  ~OffscreenCanvas();

  nsCOMPtr<nsIGlobalObject> GetGlobalObject();

  void CanvasAttrChanged()

  {

    mAttrDirty = true;

    ErrorResult dummy;

    UpdateContext(nullptr, JS::NullHandleValue, dummy);

  }

  bool mAttrDirty;

  bool mNeutered;

  bool mIsWriteOnly;

  uint32_t mWidth;

  uint32_t mHeight;

  layers::LayersBackend mCompositorBackendType;

  RefPtr<layers::CanvasClient> mCanvasClient;

  RefPtr<layers::AsyncCanvasRenderer> mCanvasRenderer;

};

} // namespace dom

} // namespace mozilla

#endif // MOZILLA_DOM_OFFSCREENCANVAS_H_