michael@0: // vim:set ts=4 sts=4 sw=4 et cin:
michael@0: /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef GFX_SHARED_MEMORYSURFACE_H
michael@0: #define GFX_SHARED_MEMORYSURFACE_H
michael@0: 
michael@0: #include "mozilla/ipc/Shmem.h"
michael@0: #include "mozilla/ipc/SharedMemory.h"
michael@0: 
michael@0: #include "gfxASurface.h"
michael@0: #include "gfxImageSurface.h"
michael@0: #include "pratom.h"
michael@0: 
michael@0: typedef struct _cairo_user_data_key cairo_user_data_key_t;
michael@0: 
michael@0: struct SharedImageInfo {
michael@0:     int32_t width;
michael@0:     int32_t height;
michael@0:     gfxImageFormat format;
michael@0:     int32_t readCount;
michael@0: };
michael@0: 
michael@0: inline SharedImageInfo*
michael@0: GetShmInfoPtr(const mozilla::ipc::Shmem& aShmem)
michael@0: {
michael@0:     return reinterpret_cast<SharedImageInfo*>
michael@0:         (aShmem.get<char>() + aShmem.Size<char>() - sizeof(SharedImageInfo));
michael@0: }
michael@0: 
michael@0: extern const cairo_user_data_key_t SHM_KEY;
michael@0: 
michael@0: template <typename Base, typename Sub>
michael@0: class gfxBaseSharedMemorySurface : public Base {
michael@0:     typedef mozilla::ipc::SharedMemory SharedMemory;
michael@0:     typedef mozilla::ipc::Shmem Shmem;
michael@0:     friend class gfxReusableSharedImageSurfaceWrapper;
michael@0: 
michael@0: public:
michael@0:     virtual ~gfxBaseSharedMemorySurface()
michael@0:     {
michael@0:         MOZ_COUNT_DTOR(gfxBaseSharedMemorySurface);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Return a new gfxSharedImageSurface around a shmem segment newly
michael@0:      * allocated by this function.  |aAllocator| is the object used to
michael@0:      * allocate the new shmem segment.  Null is returned if creating
michael@0:      * the surface failed.
michael@0:      *
michael@0:      * NB: the *caller* is responsible for freeing the Shmem allocated
michael@0:      * by this function.
michael@0:      */
michael@0:     template<class ShmemAllocator>
michael@0:     static already_AddRefed<Sub>
michael@0:     Create(ShmemAllocator* aAllocator,
michael@0:            const gfxIntSize& aSize,
michael@0:            gfxImageFormat aFormat,
michael@0:            SharedMemory::SharedMemoryType aShmType = SharedMemory::TYPE_BASIC)
michael@0:     {
michael@0:         return Create<ShmemAllocator, false>(aAllocator, aSize, aFormat, aShmType);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Return a new gfxSharedImageSurface that wraps a shmem segment
michael@0:      * already created by the Create() above.  Bad things will happen
michael@0:      * if an attempt is made to wrap any other shmem segment.  Null is
michael@0:      * returned if creating the surface failed.
michael@0:      */
michael@0:     static already_AddRefed<Sub>
michael@0:     Open(const Shmem& aShmem)
michael@0:     {
michael@0:         SharedImageInfo* shmInfo = GetShmInfoPtr(aShmem);
michael@0:         gfxIntSize size(shmInfo->width, shmInfo->height);
michael@0:         if (!gfxASurface::CheckSurfaceSize(size))
michael@0:             return nullptr;
michael@0:        
michael@0:         gfxImageFormat format = (gfxImageFormat)shmInfo->format;
michael@0:         long stride = gfxImageSurface::ComputeStride(size, format);
michael@0: 
michael@0:         nsRefPtr<Sub> s =
michael@0:             new Sub(size,
michael@0:                     stride,
michael@0:                     format,
michael@0:                     aShmem);
michael@0:         // We didn't create this Shmem and so don't free it on errors
michael@0:         return (s->CairoStatus() != 0) ? nullptr : s.forget();
michael@0:     }
michael@0: 
michael@0:     template<class ShmemAllocator>
michael@0:     static already_AddRefed<Sub>
michael@0:     CreateUnsafe(ShmemAllocator* aAllocator,
michael@0:                  const gfxIntSize& aSize,
michael@0:                  gfxImageFormat aFormat,
michael@0:                  SharedMemory::SharedMemoryType aShmType = SharedMemory::TYPE_BASIC)
michael@0:     {
michael@0:         return Create<ShmemAllocator, true>(aAllocator, aSize, aFormat, aShmType);
michael@0:     }
michael@0: 
michael@0:     Shmem& GetShmem() { return mShmem; }
michael@0: 
michael@0:     static bool IsSharedImage(gfxASurface *aSurface)
michael@0:     {
michael@0:         return (aSurface
michael@0:                 && aSurface->GetType() == gfxSurfaceType::Image
michael@0:                 && aSurface->GetData(&SHM_KEY));
michael@0:     }
michael@0: 
michael@0: protected:
michael@0:     gfxBaseSharedMemorySurface(const gfxIntSize& aSize, long aStride, 
michael@0:                                gfxImageFormat aFormat, 
michael@0:                                const Shmem& aShmem)
michael@0:       : Base(aShmem.get<unsigned char>(), aSize, aStride, aFormat)
michael@0:     {
michael@0:         MOZ_COUNT_CTOR(gfxBaseSharedMemorySurface);
michael@0: 
michael@0:         mShmem = aShmem;
michael@0:         this->SetData(&SHM_KEY, this, nullptr);
michael@0:     }
michael@0: 
michael@0: private:
michael@0:     void WriteShmemInfo()
michael@0:     {
michael@0:         SharedImageInfo* shmInfo = GetShmInfoPtr(mShmem);
michael@0:         shmInfo->width = this->mSize.width;
michael@0:         shmInfo->height = this->mSize.height;
michael@0:         shmInfo->format = this->mFormat;
michael@0:         shmInfo->readCount = 0;
michael@0:     }
michael@0: 
michael@0:     int32_t
michael@0:     ReadLock()
michael@0:     {
michael@0:         SharedImageInfo* shmInfo = GetShmInfoPtr(mShmem);
michael@0:         return PR_ATOMIC_INCREMENT(&shmInfo->readCount);
michael@0:     }
michael@0: 
michael@0:     int32_t
michael@0:     ReadUnlock()
michael@0:     {
michael@0:         SharedImageInfo* shmInfo = GetShmInfoPtr(mShmem);
michael@0:         return PR_ATOMIC_DECREMENT(&shmInfo->readCount);
michael@0:     }
michael@0: 
michael@0:     int32_t
michael@0:     GetReadCount()
michael@0:     {
michael@0:         SharedImageInfo* shmInfo = GetShmInfoPtr(mShmem);
michael@0:         return shmInfo->readCount;
michael@0:     }
michael@0: 
michael@0:     static size_t GetAlignedSize(const gfxIntSize& aSize, long aStride)
michael@0:     {
michael@0:         #define MOZ_ALIGN_WORD(x) (((x) + 3) & ~3)
michael@0:         return MOZ_ALIGN_WORD(sizeof(SharedImageInfo) + aSize.height * aStride);
michael@0:     }
michael@0: 
michael@0:     template<class ShmemAllocator, bool Unsafe>
michael@0:     static already_AddRefed<Sub>
michael@0:     Create(ShmemAllocator* aAllocator,
michael@0:            const gfxIntSize& aSize,
michael@0:            gfxImageFormat aFormat,
michael@0:            SharedMemory::SharedMemoryType aShmType)
michael@0:     {
michael@0:         if (!gfxASurface::CheckSurfaceSize(aSize))
michael@0:             return nullptr;
michael@0: 
michael@0:         Shmem shmem;
michael@0:         long stride = gfxImageSurface::ComputeStride(aSize, aFormat);
michael@0:         size_t size = GetAlignedSize(aSize, stride);
michael@0:         if (!Unsafe) {
michael@0:             if (!aAllocator->AllocShmem(size, aShmType, &shmem))
michael@0:                 return nullptr;
michael@0:         } else {
michael@0:             if (!aAllocator->AllocUnsafeShmem(size, aShmType, &shmem))
michael@0:                 return nullptr;
michael@0:         }
michael@0: 
michael@0:         nsRefPtr<Sub> s =
michael@0:             new Sub(aSize, stride, aFormat, shmem);
michael@0:         if (s->CairoStatus() != 0) {
michael@0:             aAllocator->DeallocShmem(shmem);
michael@0:             return nullptr;
michael@0:         }
michael@0:         s->WriteShmemInfo();
michael@0:         return s.forget();
michael@0:     }
michael@0: 
michael@0:     Shmem mShmem;
michael@0: 
michael@0:     // Calling these is very bad, disallow it
michael@0:     gfxBaseSharedMemorySurface(const gfxBaseSharedMemorySurface&);
michael@0:     gfxBaseSharedMemorySurface& operator=(const gfxBaseSharedMemorySurface&);
michael@0: };
michael@0: 
michael@0: #endif /* GFX_SHARED_MEMORYSURFACE_H */