gecko-dev/gfx/gl/SharedSurface.h

/* -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 4; -*- */
/* 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/. */

/* SharedSurface abstracts an actual surface (can be a GL texture, but
 * not necessarily) that handles sharing.
 * Its specializations are:
 *     SharedSurface_Basic (client-side bitmap, does readback)
 *     SharedSurface_GLTexture
 *     SharedSurface_EGLImage
 *     SharedSurface_ANGLEShareHandle
 */

#ifndef SHARED_SURFACE_H_
#define SHARED_SURFACE_H_

#include <queue>
#include <set>
#include <stdint.h>

#include "GLContextTypes.h"
#include "GLDefs.h"
#include "mozilla/Attributes.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/gfx/Point.h"
#include "mozilla/Mutex.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/WeakPtr.h"
#include "ScopedGLHelpers.h"
#include "SurfaceTypes.h"

class nsIThread;

namespace mozilla {
namespace gfx {
class DataSourceSurface;
class DrawTarget;
}  // namespace gfx

namespace layers {
class LayersIPCChannel;
class SharedSurfaceTextureClient;
enum class TextureFlags : uint32_t;
class SurfaceDescriptor;
class TextureClient;
}  // namespace layers

namespace gl {

class GLContext;
class SurfaceFactory;
class ShSurfHandle;

class SharedSurface {
 public:
  static bool ProdCopy(SharedSurface* src, SharedSurface* dest,
                       SurfaceFactory* factory);

  const SharedSurfaceType mType;
  const AttachmentType mAttachType;
  const WeakPtr<GLContext> mGL;
  const gfx::IntSize mSize;
  const bool mHasAlpha;
  const bool mCanRecycle;

 protected:
  bool mIsLocked;
  bool mIsProducerAcquired;

  SharedSurface(SharedSurfaceType type, AttachmentType attachType,
                GLContext* gl, const gfx::IntSize& size, bool hasAlpha,
                bool canRecycle);

 public:
  virtual ~SharedSurface();

  // Specifies to the TextureClient any flags which
  // are required by the SharedSurface backend.
  virtual layers::TextureFlags GetTextureFlags() const;

  bool IsLocked() const { return mIsLocked; }
  bool IsProducerAcquired() const { return mIsProducerAcquired; }

  // This locks the SharedSurface as the production buffer for the context.
  // This is needed by backends which use PBuffers and/or EGLSurfaces.
  void LockProd();

  // Unlocking is harmless if we're already unlocked.
  void UnlockProd();

  // This surface has been moved to the front buffer and will not be locked
  // again until it is recycled. Do any finalization steps here.
  virtual void Commit() {}

 protected:
  virtual void LockProdImpl() = 0;
  virtual void UnlockProdImpl() = 0;

  virtual void ProducerAcquireImpl() = 0;
  virtual void ProducerReleaseImpl() = 0;
  virtual void ProducerReadAcquireImpl() { ProducerAcquireImpl(); }
  virtual void ProducerReadReleaseImpl() { ProducerReleaseImpl(); }

 public:
  void ProducerAcquire() {
    MOZ_ASSERT(!mIsProducerAcquired);
    ProducerAcquireImpl();
    mIsProducerAcquired = true;
  }
  void ProducerRelease() {
    MOZ_ASSERT(mIsProducerAcquired);
    ProducerReleaseImpl();
    mIsProducerAcquired = false;
  }
  void ProducerReadAcquire() {
    MOZ_ASSERT(!mIsProducerAcquired);
    ProducerReadAcquireImpl();
    mIsProducerAcquired = true;
  }
  void ProducerReadRelease() {
    MOZ_ASSERT(mIsProducerAcquired);
    ProducerReadReleaseImpl();
    mIsProducerAcquired = false;
  }

  // This function waits until the buffer is no longer being used.
  // To optimize the performance, some implementaions recycle SharedSurfaces
  // even when its buffer is still being used.
  virtual void WaitForBufferOwnership() {}

  // Returns true if the buffer is available.
  // You can call WaitForBufferOwnership to wait for availability.
  virtual bool IsBufferAvailable() const { return true; }

  // For use when AttachType is correct.
  virtual GLenum ProdTextureTarget() const {
    MOZ_ASSERT(mAttachType == AttachmentType::GLTexture);
    return LOCAL_GL_TEXTURE_2D;
  }

  virtual GLuint ProdTexture() {
    MOZ_ASSERT(mAttachType == AttachmentType::GLTexture);
    MOZ_CRASH("GFX: Did you forget to override this function?");
  }

  virtual GLuint ProdRenderbuffer() {
    MOZ_ASSERT(mAttachType == AttachmentType::GLRenderbuffer);
    MOZ_CRASH("GFX: Did you forget to override this function?");
  }

  virtual bool CopyTexImage2D(GLenum target, GLint level, GLenum internalformat,
                              GLint x, GLint y, GLsizei width, GLsizei height,
                              GLint border) {
    return false;
  }

  virtual bool ReadPixels(GLint x, GLint y, GLsizei width, GLsizei height,
                          GLenum format, GLenum type, GLvoid* pixels) {
    return false;
  }

  virtual bool NeedsIndirectReads() const { return false; }

  virtual bool ToSurfaceDescriptor(
      layers::SurfaceDescriptor* const out_descriptor) = 0;

  virtual bool ReadbackBySharedHandle(gfx::DataSourceSurface* out_surface) {
    return false;
  }
};

template <typename T>
class RefSet {
  std::set<T*> mSet;

 public:
  ~RefSet() { clear(); }

  auto begin() -> decltype(mSet.begin()) { return mSet.begin(); }

  void clear() {
    for (auto itr = mSet.begin(); itr != mSet.end(); ++itr) {
      (*itr)->Release();
    }
    mSet.clear();
  }

  bool empty() const { return mSet.empty(); }

  bool insert(T* x) {
    if (mSet.insert(x).second) {
      x->AddRef();
      return true;
    }

    return false;
  }

  bool erase(T* x) {
    if (mSet.erase(x)) {
      x->Release();
      return true;
    }

    return false;
  }
};

template <typename T>
class RefQueue {
  std::queue<T*> mQueue;

 public:
  ~RefQueue() { clear(); }

  void clear() {
    while (!empty()) {
      pop();
    }
  }

  bool empty() const { return mQueue.empty(); }

  size_t size() const { return mQueue.size(); }

  void push(T* x) {
    mQueue.push(x);
    x->AddRef();
  }

  T* front() const { return mQueue.front(); }

  void pop() {
    T* x = mQueue.front();
    x->Release();
    mQueue.pop();
  }
};

class SurfaceFactory : public SupportsWeakPtr<SurfaceFactory> {
 public:
  // Should use the VIRTUAL version, but it's currently incompatible
  // with SupportsWeakPtr. (bug 1049278)
  MOZ_DECLARE_WEAKREFERENCE_TYPENAME(SurfaceFactory)

  const SharedSurfaceType mType;
  GLContext* const mGL;
  const SurfaceCaps mCaps;
  const RefPtr<layers::LayersIPCChannel> mAllocator;
  const layers::TextureFlags mFlags;
  const GLFormats mFormats;
  Mutex mMutex;

 protected:
  SurfaceCaps mDrawCaps;
  SurfaceCaps mReadCaps;
  RefQueue<layers::SharedSurfaceTextureClient> mRecycleFreePool;
  RefSet<layers::SharedSurfaceTextureClient> mRecycleTotalPool;

  SurfaceFactory(SharedSurfaceType type, GLContext* gl, const SurfaceCaps& caps,
                 const RefPtr<layers::LayersIPCChannel>& allocator,
                 const layers::TextureFlags& flags);

 public:
  virtual ~SurfaceFactory();

  const SurfaceCaps& DrawCaps() const { return mDrawCaps; }

  const SurfaceCaps& ReadCaps() const { return mReadCaps; }

 protected:
  virtual UniquePtr<SharedSurface> CreateShared(const gfx::IntSize& size) = 0;

  void StartRecycling(layers::SharedSurfaceTextureClient* tc);
  void SetRecycleCallback(layers::SharedSurfaceTextureClient* tc);
  void StopRecycling(layers::SharedSurfaceTextureClient* tc);

 public:
  UniquePtr<SharedSurface> NewSharedSurface(const gfx::IntSize& size);
  // already_AddRefed<ShSurfHandle> NewShSurfHandle(const gfx::IntSize& size);
  already_AddRefed<layers::SharedSurfaceTextureClient> NewTexClient(
      const gfx::IntSize& size);

  static void RecycleCallback(layers::TextureClient* tc, void* /*closure*/);

  // Auto-deletes surfs of the wrong type.
  bool Recycle(layers::SharedSurfaceTextureClient* texClient);
};

class ScopedReadbackFB final {
  GLContext* const mGL;
  ScopedBindFramebuffer mAutoFB;
  GLuint mTempFB = 0;
  GLuint mTempTex = 0;
  SharedSurface* mSurfToUnlock = nullptr;
  SharedSurface* mSurfToLock = nullptr;

 public:
  explicit ScopedReadbackFB(SharedSurface* src);
  ~ScopedReadbackFB();
};

bool ReadbackSharedSurface(SharedSurface* src, gfx::DrawTarget* dst);
uint32_t ReadPixel(SharedSurface* src);

}  // namespace gl
}  // namespace mozilla

#endif  // SHARED_SURFACE_H_