Move platform abstraction to base library

src/platform/mutex.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_MUTEX_H_
-#define V8_PLATFORM_MUTEX_H_
-
-#include "src/base/lazy-instance.h"
-#if V8_OS_WIN
-#include "src/base/win32-headers.h"
-#endif
-#include "src/checks.h"
-
-#if V8_OS_POSIX
-#include <pthread.h>  // NOLINT
-#endif
-
-namespace v8 {
-namespace internal {
-
-// ----------------------------------------------------------------------------
-// Mutex
-//
-// This class is a synchronization primitive that can be used to protect shared
-// data from being simultaneously accessed by multiple threads. A mutex offers
-// exclusive, non-recursive ownership semantics:
-// - A calling thread owns a mutex from the time that it successfully calls
-//   either |Lock()| or |TryLock()| until it calls |Unlock()|.
-// - When a thread owns a mutex, all other threads will block (for calls to
-//   |Lock()|) or receive a |false| return value (for |TryLock()|) if they
-//   attempt to claim ownership of the mutex.
-// A calling thread must not own the mutex prior to calling |Lock()| or
-// |TryLock()|. The behavior of a program is undefined if a mutex is destroyed
-// while still owned by some thread. The Mutex class is non-copyable.
-
-class Mutex V8_FINAL {
- public:
-  Mutex();
-  ~Mutex();
-
-  // Locks the given mutex. If the mutex is currently unlocked, it becomes
-  // locked and owned by the calling thread, and immediately. If the mutex
-  // is already locked by another thread, suspends the calling thread until
-  // the mutex is unlocked.
-  void Lock();
-
-  // Unlocks the given mutex. The mutex is assumed to be locked and owned by
-  // the calling thread on entrance.
-  void Unlock();
-
-  // Tries to lock the given mutex. Returns whether the mutex was
-  // successfully locked.
-  bool TryLock() V8_WARN_UNUSED_RESULT;
-
-  // The implementation-defined native handle type.
-#if V8_OS_POSIX
-  typedef pthread_mutex_t NativeHandle;
-#elif V8_OS_WIN
-  typedef CRITICAL_SECTION NativeHandle;
-#endif
-
-  NativeHandle& native_handle() {
-    return native_handle_;
-  }
-  const NativeHandle& native_handle() const {
-    return native_handle_;
-  }
-
- private:
-  NativeHandle native_handle_;
-#ifdef DEBUG
-  int level_;
-#endif
-
-  V8_INLINE void AssertHeldAndUnmark() {
-#ifdef DEBUG
-    ASSERT_EQ(1, level_);
-    level_--;
-#endif
-  }
-
-  V8_INLINE void AssertUnheldAndMark() {
-#ifdef DEBUG
-    ASSERT_EQ(0, level_);
-    level_++;
-#endif
-  }
-
-  friend class ConditionVariable;
-
-  DISALLOW_COPY_AND_ASSIGN(Mutex);
-};
-
-
-// POD Mutex initialized lazily (i.e. the first time Pointer() is called).
-// Usage:
-//   static LazyMutex my_mutex = LAZY_MUTEX_INITIALIZER;
-//
-//   void my_function() {
-//     LockGuard<Mutex> guard(my_mutex.Pointer());
-//     // Do something.
-//   }
-//
-typedef v8::base::LazyStaticInstance<
-    Mutex, v8::base::DefaultConstructTrait<Mutex>,
-    v8::base::ThreadSafeInitOnceTrait>::type LazyMutex;
-
-#define LAZY_MUTEX_INITIALIZER LAZY_STATIC_INSTANCE_INITIALIZER
-
-
-// -----------------------------------------------------------------------------
-// RecursiveMutex
-//
-// This class is a synchronization primitive that can be used to protect shared
-// data from being simultaneously accessed by multiple threads. A recursive
-// mutex offers exclusive, recursive ownership semantics:
-// - A calling thread owns a recursive mutex for a period of time that starts
-//   when it successfully calls either |Lock()| or |TryLock()|. During this
-//   period, the thread may make additional calls to |Lock()| or |TryLock()|.
-//   The period of ownership ends when the thread makes a matching number of
-//   calls to |Unlock()|.
-// - When a thread owns a recursive mutex, all other threads will block (for
-//   calls to |Lock()|) or receive a |false| return value (for |TryLock()|) if
-//   they attempt to claim ownership of the recursive mutex.
-// - The maximum number of times that a recursive mutex may be locked is
-//   unspecified, but after that number is reached, calls to |Lock()| will
-//   probably abort the process and calls to |TryLock()| return false.
-// The behavior of a program is undefined if a recursive mutex is destroyed
-// while still owned by some thread. The RecursiveMutex class is non-copyable.
-
-class RecursiveMutex V8_FINAL {
- public:
-  RecursiveMutex();
-  ~RecursiveMutex();
-
-  // Locks the mutex. If another thread has already locked the mutex, a call to
-  // |Lock()| will block execution until the lock is acquired. A thread may call
-  // |Lock()| on a recursive mutex repeatedly. Ownership will only be released
-  // after the thread makes a matching number of calls to |Unlock()|.
-  // The behavior is undefined if the mutex is not unlocked before being
-  // destroyed, i.e. some thread still owns it.
-  void Lock();
-
-  // Unlocks the mutex if its level of ownership is 1 (there was exactly one
-  // more call to |Lock()| than there were calls to unlock() made by this
-  // thread), reduces the level of ownership by 1 otherwise. The mutex must be
-  // locked by the current thread of execution, otherwise, the behavior is
-  // undefined.
-  void Unlock();
-
-  // Tries to lock the given mutex. Returns whether the mutex was
-  // successfully locked.
-  bool TryLock() V8_WARN_UNUSED_RESULT;
-
-  // The implementation-defined native handle type.
-  typedef Mutex::NativeHandle NativeHandle;
-
-  NativeHandle& native_handle() {
-    return native_handle_;
-  }
-  const NativeHandle& native_handle() const {
-    return native_handle_;
-  }
-
- private:
-  NativeHandle native_handle_;
-#ifdef DEBUG
-  int level_;
-#endif
-
-  DISALLOW_COPY_AND_ASSIGN(RecursiveMutex);
-};
-
-
-// POD RecursiveMutex initialized lazily (i.e. the first time Pointer() is
-// called).
-// Usage:
-//   static LazyRecursiveMutex my_mutex = LAZY_RECURSIVE_MUTEX_INITIALIZER;
-//
-//   void my_function() {
-//     LockGuard<RecursiveMutex> guard(my_mutex.Pointer());
-//     // Do something.
-//   }
-//
-typedef v8::base::LazyStaticInstance<
-    RecursiveMutex, v8::base::DefaultConstructTrait<RecursiveMutex>,
-    v8::base::ThreadSafeInitOnceTrait>::type LazyRecursiveMutex;
-
-#define LAZY_RECURSIVE_MUTEX_INITIALIZER LAZY_STATIC_INSTANCE_INITIALIZER
-
-
-// -----------------------------------------------------------------------------
-// LockGuard
-//
-// This class is a mutex wrapper that provides a convenient RAII-style mechanism
-// for owning a mutex for the duration of a scoped block.
-// When a LockGuard object is created, it attempts to take ownership of the
-// mutex it is given. When control leaves the scope in which the LockGuard
-// object was created, the LockGuard is destructed and the mutex is released.
-// The LockGuard class is non-copyable.
-
-template <typename Mutex>
-class LockGuard V8_FINAL {
- public:
-  explicit LockGuard(Mutex* mutex) : mutex_(mutex) { mutex_->Lock(); }
-  ~LockGuard() { mutex_->Unlock(); }
-
- private:
-  Mutex* mutex_;
-
-  DISALLOW_COPY_AND_ASSIGN(LockGuard);
-};
-
-} }  // namespace v8::internal
-
-#endif  // V8_PLATFORM_MUTEX_H_