| /* |
| * Copyright 2013 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include <unistd.h> |
| #include <sys/mman.h> |
| #include "SkDiscardableMemory.h" |
| #include "SkTypes.h" |
| #include "android/ashmem.h" |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| namespace { |
| /** |
| * DiscardableMemory implementation that uses the Android kernel's |
| * ashmem (Android shared memory). |
| */ |
| class SkAshmemDiscardableMemory : public SkDiscardableMemory { |
| public: |
| SkAshmemDiscardableMemory(int fd, void* address, size_t size); |
| virtual ~SkAshmemDiscardableMemory(); |
| virtual bool lock() SK_OVERRIDE; |
| virtual void* data() SK_OVERRIDE; |
| virtual void unlock() SK_OVERRIDE; |
| private: |
| bool fLocked; |
| int fFd; |
| void* fMemory; |
| const size_t fSize; |
| }; |
| |
| SkAshmemDiscardableMemory::SkAshmemDiscardableMemory(int fd, |
| void* address, |
| size_t size) |
| : fLocked(true) // Ashmem pages are pinned by default. |
| , fFd(fd) |
| , fMemory(address) |
| , fSize(size) { |
| SkASSERT(fFd >= 0); |
| SkASSERT(fMemory != NULL); |
| SkASSERT(fSize > 0); |
| } |
| |
| SkAshmemDiscardableMemory::~SkAshmemDiscardableMemory() { |
| SkASSERT(!fLocked); |
| if (NULL != fMemory) { |
| munmap(fMemory, fSize); |
| } |
| if (fFd != -1) { |
| close(fFd); |
| } |
| } |
| |
| bool SkAshmemDiscardableMemory::lock() { |
| SkASSERT(!fLocked); |
| if (-1 == fFd) { |
| fLocked = false; |
| return false; |
| } |
| SkASSERT(fMemory != NULL); |
| if (fLocked || (ASHMEM_NOT_PURGED == ashmem_pin_region(fFd, 0, 0))) { |
| fLocked = true; |
| return true; |
| } else { |
| munmap(fMemory, fSize); |
| fMemory = NULL; |
| |
| close(fFd); |
| fFd = -1; |
| fLocked = false; |
| return false; |
| } |
| } |
| |
| void* SkAshmemDiscardableMemory::data() { |
| SkASSERT(fLocked); |
| return fLocked ? fMemory : NULL; |
| } |
| |
| void SkAshmemDiscardableMemory::unlock() { |
| SkASSERT(fLocked); |
| if (fLocked && (fFd != -1)) { |
| ashmem_unpin_region(fFd, 0, 0); |
| } |
| fLocked = false; |
| } |
| } // namespace |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| SkDiscardableMemory* SkDiscardableMemory::Create(size_t bytes) { |
| // ashmem likes lengths on page boundaries. |
| const size_t mask = getpagesize() - 1; |
| size_t size = (bytes + mask) & ~mask; |
| |
| static const char name[] = "Skia_Ashmem_Discardable_Memory"; |
| int fd = ashmem_create_region(name, size); |
| if (fd < 0) { |
| return NULL; |
| } |
| if (0 != ashmem_set_prot_region(fd, PROT_READ | PROT_WRITE)) { |
| close(fd); |
| return NULL; |
| } |
| void* addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); |
| if ((MAP_FAILED == addr) || (NULL == addr)) { |
| close(fd); |
| return NULL; |
| } |
| |
| return SkNEW_ARGS(SkAshmemDiscardableMemory, (fd, addr, size)); |
| } |