Move platform abstraction to base library

src/platform/semaphore.h

-// Copyright 2013 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef V8_PLATFORM_SEMAPHORE_H_
-#define V8_PLATFORM_SEMAPHORE_H_
-
-#include "src/base/lazy-instance.h"
-#if V8_OS_WIN
-#include "src/base/win32-headers.h"
-#endif
-
-#if V8_OS_MACOSX
-#include <mach/semaphore.h>  // NOLINT
-#elif V8_OS_POSIX
-#include <semaphore.h>  // NOLINT
-#endif
-
-namespace v8 {
-namespace internal {
-
-// Forward declarations.
-class TimeDelta;
-
-// ----------------------------------------------------------------------------
-// Semaphore
-//
-// A semaphore object is a synchronization object that maintains a count. The
-// count is decremented each time a thread completes a wait for the semaphore
-// object and incremented each time a thread signals the semaphore. When the
-// count reaches zero,  threads waiting for the semaphore blocks until the
-// count becomes non-zero.
-
-class Semaphore V8_FINAL {
- public:
-  explicit Semaphore(int count);
-  ~Semaphore();
-
-  // Increments the semaphore counter.
-  void Signal();
-
-  // Suspends the calling thread until the semaphore counter is non zero
-  // and then decrements the semaphore counter.
-  void Wait();
-
-  // Suspends the calling thread until the counter is non zero or the timeout
-  // time has passed. If timeout happens the return value is false and the
-  // counter is unchanged. Otherwise the semaphore counter is decremented and
-  // true is returned.
-  bool WaitFor(const TimeDelta& rel_time) V8_WARN_UNUSED_RESULT;
-
-#if V8_OS_MACOSX
-  typedef semaphore_t NativeHandle;
-#elif V8_OS_POSIX
-  typedef sem_t NativeHandle;
-#elif V8_OS_WIN
-  typedef HANDLE NativeHandle;
-#endif
-
-  NativeHandle& native_handle() {
-    return native_handle_;
-  }
-  const NativeHandle& native_handle() const {
-    return native_handle_;
-  }
-
- private:
-  NativeHandle native_handle_;
-
-  DISALLOW_COPY_AND_ASSIGN(Semaphore);
-};
-
-
-// POD Semaphore initialized lazily (i.e. the first time Pointer() is called).
-// Usage:
-//   // The following semaphore starts at 0.
-//   static LazySemaphore<0>::type my_semaphore = LAZY_SEMAPHORE_INITIALIZER;
-//
-//   void my_function() {
-//     // Do something with my_semaphore.Pointer().
-//   }
-//
-
-template <int N>
-struct CreateSemaphoreTrait {
-  static Semaphore* Create() {
-    return new Semaphore(N);
-  }
-};
-
-template <int N>
-struct LazySemaphore {
-  typedef typename v8::base::LazyDynamicInstance<
-      Semaphore,
-      CreateSemaphoreTrait<N>,
-      v8::base::ThreadSafeInitOnceTrait>::type type;
-};
-
-#define LAZY_SEMAPHORE_INITIALIZER LAZY_DYNAMIC_INSTANCE_INITIALIZER
-
-} }  // namespace v8::internal
-
-#endif  // V8_PLATFORM_SEMAPHORE_H_