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// vim:set ts=4 sts=2 sw=2 et cin:
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* 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
#ifndef GFX_SHARED_MEMORYSURFACE_H
#define GFX_SHARED_MEMORYSURFACE_H
#include "mozilla/gfx/2D.h"
#include "mozilla/ipc/Shmem.h"
#include "mozilla/ipc/SharedMemory.h"
#include "gfxASurface.h"
#include "gfxImageSurface.h"
#include "pratom.h"
typedef struct _cairo_user_data_key cairo_user_data_key_t;
struct SharedImageInfo {
int32_t width;
int32_t height;
gfxImageFormat format;
int32_t readCount;
};
inline SharedImageInfo* GetShmInfoPtr(const mozilla::ipc::Shmem& aShmem) {
return reinterpret_cast<SharedImageInfo*>(
aShmem.get<char>() + aShmem.Size<char>() - sizeof(SharedImageInfo));
}
extern const cairo_user_data_key_t SHM_KEY;
template <typename Base, typename Sub>
class gfxBaseSharedMemorySurface : public Base {
typedef mozilla::ipc::SharedMemory SharedMemory;
typedef mozilla::ipc::Shmem Shmem;
protected:
virtual ~gfxBaseSharedMemorySurface() {
MOZ_COUNT_DTOR(gfxBaseSharedMemorySurface);
}
public:
/**
* Return a new gfxSharedImageSurface around a shmem segment newly
* allocated by this function. |aAllocator| is the object used to
* allocate the new shmem segment. Null is returned if creating
* the surface failed.
*
* NB: the *caller* is responsible for freeing the Shmem allocated
* by this function.
*/
template <class ShmemAllocator>
static already_AddRefed<Sub> Create(ShmemAllocator* aAllocator,
const mozilla::gfx::IntSize& aSize,
gfxImageFormat aFormat) {
return Create<ShmemAllocator, false>(aAllocator, aSize, aFormat);
}
/**
* Return a new gfxSharedImageSurface that wraps a shmem segment
* already created by the Create() above. Bad things will happen
* if an attempt is made to wrap any other shmem segment. Null is
* returned if creating the surface failed.
*/
static already_AddRefed<Sub> Open(const Shmem& aShmem) {
SharedImageInfo* shmInfo = GetShmInfoPtr(aShmem);
mozilla::gfx::IntSize size(shmInfo->width, shmInfo->height);
if (!mozilla::gfx::Factory::CheckSurfaceSize(size)) return nullptr;
gfxImageFormat format = shmInfo->format;
long stride = gfxImageSurface::ComputeStride(size, format);
RefPtr<Sub> s = new Sub(size, stride, format, aShmem);
// We didn't create this Shmem and so don't free it on errors
return (s->CairoStatus() != 0) ? nullptr : s.forget();
}
template <class ShmemAllocator>
static already_AddRefed<Sub> CreateUnsafe(ShmemAllocator* aAllocator,
const mozilla::gfx::IntSize& aSize,
gfxImageFormat aFormat) {
return Create<ShmemAllocator, true>(aAllocator, aSize, aFormat);
}
Shmem& GetShmem() { return mShmem; }
static bool IsSharedImage(gfxASurface* aSurface) {
return (aSurface && aSurface->GetType() == gfxSurfaceType::Image &&
aSurface->GetData(&SHM_KEY));
}
protected:
gfxBaseSharedMemorySurface(const mozilla::gfx::IntSize& aSize, long aStride,
gfxImageFormat aFormat, const Shmem& aShmem)
: Base(aShmem.get<unsigned char>(), aSize, aStride, aFormat) {
MOZ_COUNT_CTOR(gfxBaseSharedMemorySurface);
mShmem = aShmem;
this->SetData(&SHM_KEY, this, nullptr);
}
private:
void WriteShmemInfo() {
SharedImageInfo* shmInfo = GetShmInfoPtr(mShmem);
shmInfo->width = this->mSize.width;
shmInfo->height = this->mSize.height;
shmInfo->format = this->mFormat;
shmInfo->readCount = 0;
}
int32_t ReadLock() {
SharedImageInfo* shmInfo = GetShmInfoPtr(mShmem);
return PR_ATOMIC_INCREMENT(&shmInfo->readCount);
}
int32_t ReadUnlock() {
SharedImageInfo* shmInfo = GetShmInfoPtr(mShmem);
return PR_ATOMIC_DECREMENT(&shmInfo->readCount);
}
int32_t GetReadCount() {
SharedImageInfo* shmInfo = GetShmInfoPtr(mShmem);
return shmInfo->readCount;
}
static size_t GetAlignedSize(const mozilla::gfx::IntSize& aSize,
long aStride) {
#define MOZ_ALIGN_WORD(x) (((x) + 3) & ~3)
return MOZ_ALIGN_WORD(sizeof(SharedImageInfo) + aSize.height * aStride);
}
template <class ShmemAllocator, bool Unsafe>
static already_AddRefed<Sub> Create(ShmemAllocator* aAllocator,
const mozilla::gfx::IntSize& aSize,
gfxImageFormat aFormat) {
if (!mozilla::gfx::Factory::CheckSurfaceSize(aSize)) return nullptr;
Shmem shmem;
long stride = gfxImageSurface::ComputeStride(aSize, aFormat);
size_t size = GetAlignedSize(aSize, stride);
if (!Unsafe) {
if (!aAllocator->AllocShmem(size, &shmem)) return nullptr;
} else {
if (!aAllocator->AllocUnsafeShmem(size, &shmem)) return nullptr;
}
RefPtr<Sub> s = new Sub(aSize, stride, aFormat, shmem);
if (s->CairoStatus() != 0) {
aAllocator->DeallocShmem(shmem);
return nullptr;
}
s->WriteShmemInfo();
return s.forget();
}
Shmem mShmem;
// Calling these is very bad, disallow it
gfxBaseSharedMemorySurface(const gfxBaseSharedMemorySurface&);
gfxBaseSharedMemorySurface& operator=(const gfxBaseSharedMemorySurface&);
};
#endif /* GFX_SHARED_MEMORYSURFACE_H */