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: #include "VolatileBuffer.h"
michael@0: #include "mozilla/Assertions.h"
michael@0: #include "mozilla/NullPtr.h"
michael@0: #include "mozilla/mozalloc.h"
michael@0: 
michael@0: #include <fcntl.h>
michael@0: #include <linux/ashmem.h>
michael@0: #include <sys/mman.h>
michael@0: #include <sys/stat.h>
michael@0: #include <sys/types.h>
michael@0: #include <unistd.h>
michael@0: 
michael@0: #ifdef MOZ_MEMORY
michael@0: #ifdef MOZ_WIDGET_ANDROID
michael@0: extern "C" int __wrap_posix_memalign(void** memptr, size_t alignment, size_t size);
michael@0: #else
michael@0: extern "C" int posix_memalign(void** memptr, size_t alignment, size_t size);
michael@0: #endif
michael@0: #endif
michael@0: 
michael@0: #define MIN_VOLATILE_ALLOC_SIZE 8192
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: VolatileBuffer::VolatileBuffer()
michael@0:   : mBuf(nullptr)
michael@0:   , mSize(0)
michael@0:   , mLockCount(0)
michael@0:   , mFd(-1)
michael@0: {
michael@0: }
michael@0: 
michael@0: bool
michael@0: VolatileBuffer::Init(size_t aSize, size_t aAlignment)
michael@0: {
michael@0:   MOZ_ASSERT(!mSize && !mBuf, "Init called twice");
michael@0:   MOZ_ASSERT(!(aAlignment % sizeof(void *)),
michael@0:          "Alignment must be multiple of pointer size");
michael@0: 
michael@0:   mSize = aSize;
michael@0:   if (aSize < MIN_VOLATILE_ALLOC_SIZE) {
michael@0:     goto heap_alloc;
michael@0:   }
michael@0: 
michael@0:   mFd = open("/" ASHMEM_NAME_DEF, O_RDWR);
michael@0:   if (mFd < 0) {
michael@0:     goto heap_alloc;
michael@0:   }
michael@0: 
michael@0:   if (ioctl(mFd, ASHMEM_SET_SIZE, mSize) < 0) {
michael@0:     close(mFd);
michael@0:     mFd = -1;
michael@0:     goto heap_alloc;
michael@0:   }
michael@0: 
michael@0:   mBuf = mmap(nullptr, mSize, PROT_READ | PROT_WRITE, MAP_SHARED, mFd, 0);
michael@0:   if (mBuf != MAP_FAILED) {
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0: heap_alloc:
michael@0: #ifdef MOZ_MEMORY
michael@0: #ifdef MOZ_WIDGET_ANDROID
michael@0:   __wrap_posix_memalign(&mBuf, aAlignment, aSize);
michael@0: #else
michael@0:   posix_memalign(&mBuf, aAlignment, aSize);
michael@0: #endif
michael@0: #else
michael@0:   mBuf = memalign(aAlignment, aSize);
michael@0: #endif
michael@0:   return !!mBuf;
michael@0: }
michael@0: 
michael@0: VolatileBuffer::~VolatileBuffer()
michael@0: {
michael@0:   if (OnHeap()) {
michael@0:     free(mBuf);
michael@0:   } else {
michael@0:     munmap(mBuf, mSize);
michael@0:     close(mFd);
michael@0:   }
michael@0: }
michael@0: 
michael@0: bool
michael@0: VolatileBuffer::Lock(void** aBuf)
michael@0: {
michael@0:   MOZ_ASSERT(mBuf, "Attempting to lock an uninitialized VolatileBuffer");
michael@0: 
michael@0:   *aBuf = mBuf;
michael@0:   if (++mLockCount > 1 || OnHeap()) {
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   // Zero offset and zero length means we want to pin/unpin the entire thing.
michael@0:   struct ashmem_pin pin = { 0, 0 };
michael@0:   return ioctl(mFd, ASHMEM_PIN, &pin) == ASHMEM_NOT_PURGED;
michael@0: }
michael@0: 
michael@0: void
michael@0: VolatileBuffer::Unlock()
michael@0: {
michael@0:   MOZ_ASSERT(mLockCount > 0, "VolatileBuffer unlocked too many times!");
michael@0:   if (--mLockCount || OnHeap()) {
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   struct ashmem_pin pin = { 0, 0 };
michael@0:   ioctl(mFd, ASHMEM_UNPIN, &pin);
michael@0: }
michael@0: 
michael@0: bool
michael@0: VolatileBuffer::OnHeap() const
michael@0: {
michael@0:   return mFd < 0;
michael@0: }
michael@0: 
michael@0: size_t
michael@0: VolatileBuffer::HeapSizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
michael@0: {
michael@0:   return OnHeap() ? aMallocSizeOf(mBuf) : 0;
michael@0: }
michael@0: 
michael@0: size_t
michael@0: VolatileBuffer::NonHeapSizeOfExcludingThis() const
michael@0: {
michael@0:   if (OnHeap()) {
michael@0:     return 0;
michael@0:   }
michael@0: 
michael@0:   return (mSize + (PAGE_SIZE - 1)) & PAGE_MASK;
michael@0: }
michael@0: 
michael@0: } // namespace mozilla