1 files changed, 83 insertions, 0 deletions
diff --git a/gfx/skia/skia/src/base/SkSemaphore.cpp b/gfx/skia/skia/src/base/SkSemaphore.cpp
new file mode 100644
index 0000000000..cb85fa9745
--- /dev/null
+++ b/gfx/skia/skia/src/base/SkSemaphore.cpp
@@ -0,0 +1,83 @@
+/*
+ * 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/base/SkSemaphore.h"
+
+#include "include/private/base/SkFeatures.h" // IWYU pragma: keep
+
+#if 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)
+#include "src/base/SkLeanWindows.h"
+
+    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;
+}