| /* |
| * Copyright 2015 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "include/private/SkSemaphore.h" |
| #include "src/core/SkLeanWindows.h" |
| |
| #if defined(STARBOARD) |
| #include "starboard/common/semaphore.h" |
| |
| struct SkSemaphore::OSSemaphore { |
| starboard::Semaphore fSemaphore; |
| |
| OSSemaphore(): fSemaphore(0/*initial count*/) {} |
| |
| void signal(int n) { while (n -- > 0) { fSemaphore.Put(); } } |
| void wait() { fSemaphore.Take(); } |
| }; |
| #elif defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS) |
| #include <dispatch/dispatch.h> |
| |
| struct SkSemaphore::OSSemaphore { |
| dispatch_semaphore_t fSemaphore; |
| |
| OSSemaphore() { fSemaphore = dispatch_semaphore_create(0/*initial count*/); } |
| ~OSSemaphore() { dispatch_release(fSemaphore); } |
| |
| void signal(int n) { while (n --> 0) { dispatch_semaphore_signal(fSemaphore); } } |
| void wait() { dispatch_semaphore_wait(fSemaphore, DISPATCH_TIME_FOREVER); } |
| }; |
| #elif defined(SK_BUILD_FOR_WIN) |
| struct SkSemaphore::OSSemaphore { |
| HANDLE fSemaphore; |
| |
| OSSemaphore() { |
| fSemaphore = CreateSemaphore(nullptr /*security attributes, optional*/, |
| 0 /*initial count*/, |
| MAXLONG /*max count*/, |
| nullptr /*name, optional*/); |
| } |
| ~OSSemaphore() { CloseHandle(fSemaphore); } |
| |
| void signal(int n) { |
| ReleaseSemaphore(fSemaphore, n, nullptr/*returns previous count, optional*/); |
| } |
| void wait() { WaitForSingleObject(fSemaphore, INFINITE/*timeout in ms*/); } |
| }; |
| #else |
| // It's important we test for Mach before this. This code will compile but not work there. |
| #include <errno.h> |
| #include <semaphore.h> |
| struct SkSemaphore::OSSemaphore { |
| sem_t fSemaphore; |
| |
| OSSemaphore() { sem_init(&fSemaphore, 0/*cross process?*/, 0/*initial count*/); } |
| ~OSSemaphore() { sem_destroy(&fSemaphore); } |
| |
| void signal(int n) { while (n --> 0) { sem_post(&fSemaphore); } } |
| void wait() { |
| // Try until we're not interrupted. |
| while(sem_wait(&fSemaphore) == -1 && errno == EINTR); |
| } |
| }; |
| #endif |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| SkSemaphore::~SkSemaphore() { |
| delete fOSSemaphore; |
| } |
| |
| void SkSemaphore::osSignal(int n) { |
| fOSSemaphoreOnce([this] { fOSSemaphore = new OSSemaphore; }); |
| fOSSemaphore->signal(n); |
| } |
| |
| void SkSemaphore::osWait() { |
| fOSSemaphoreOnce([this] { fOSSemaphore = new OSSemaphore; }); |
| fOSSemaphore->wait(); |
| } |
| |
| bool SkSemaphore::try_wait() { |
| int count = fCount.load(std::memory_order_relaxed); |
| if (count > 0) { |
| return fCount.compare_exchange_weak(count, count-1, std::memory_order_acquire); |
| } |
| return false; |
| } |