Add m-esr52 at 52.6.0

9 files changed, 1190 insertions, 0 deletions

diff --git a/security/sandbox/chromium/base/synchronization/condition_variable.h b/security/sandbox/chromium/base/synchronization/condition_variable.h
new file mode 100644
index 000000000..a41b2ba5a
--- /dev/null
+++ b/security/sandbox/chromium/base/synchronization/condition_variable.h
@@ -0,0 +1,118 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// ConditionVariable wraps pthreads condition variable synchronization or, on
+// Windows, simulates it.  This functionality is very helpful for having
+// several threads wait for an event, as is common with a thread pool managed
+// by a master.  The meaning of such an event in the (worker) thread pool
+// scenario is that additional tasks are now available for processing.  It is
+// used in Chrome in the DNS prefetching system to notify worker threads that
+// a queue now has items (tasks) which need to be tended to.  A related use
+// would have a pool manager waiting on a ConditionVariable, waiting for a
+// thread in the pool to announce (signal) that there is now more room in a
+// (bounded size) communications queue for the manager to deposit tasks, or,
+// as a second example, that the queue of tasks is completely empty and all
+// workers are waiting.
+//
+// USAGE NOTE 1: spurious signal events are possible with this and
+// most implementations of condition variables.  As a result, be
+// *sure* to retest your condition before proceeding.  The following
+// is a good example of doing this correctly:
+//
+// while (!work_to_be_done()) Wait(...);
+//
+// In contrast do NOT do the following:
+//
+// if (!work_to_be_done()) Wait(...);  // Don't do this.
+//
+// Especially avoid the above if you are relying on some other thread only
+// issuing a signal up *if* there is work-to-do.  There can/will
+// be spurious signals.  Recheck state on waiting thread before
+// assuming the signal was intentional. Caveat caller ;-).
+//
+// USAGE NOTE 2: Broadcast() frees up all waiting threads at once,
+// which leads to contention for the locks they all held when they
+// called Wait().  This results in POOR performance.  A much better
+// approach to getting a lot of threads out of Wait() is to have each
+// thread (upon exiting Wait()) call Signal() to free up another
+// Wait'ing thread.  Look at condition_variable_unittest.cc for
+// both examples.
+//
+// Broadcast() can be used nicely during teardown, as it gets the job
+// done, and leaves no sleeping threads... and performance is less
+// critical at that point.
+//
+// The semantics of Broadcast() are carefully crafted so that *all*
+// threads that were waiting when the request was made will indeed
+// get signaled.  Some implementations mess up, and don't signal them
+// all, while others allow the wait to be effectively turned off (for
+// a while while waiting threads come around).  This implementation
+// appears correct, as it will not "lose" any signals, and will guarantee
+// that all threads get signaled by Broadcast().
+//
+// This implementation offers support for "performance" in its selection of
+// which thread to revive.  Performance, in direct contrast with "fairness,"
+// assures that the thread that most recently began to Wait() is selected by
+// Signal to revive.  Fairness would (if publicly supported) assure that the
+// thread that has Wait()ed the longest is selected. The default policy
+// may improve performance, as the selected thread may have a greater chance of
+// having some of its stack data in various CPU caches.
+//
+// For a discussion of the many very subtle implementation details, see the FAQ
+// at the end of condition_variable_win.cc.
+
+#ifndef BASE_SYNCHRONIZATION_CONDITION_VARIABLE_H_
+#define BASE_SYNCHRONIZATION_CONDITION_VARIABLE_H_
+
+#include "base/base_export.h"
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/synchronization/lock.h"
+#include "build/build_config.h"
+
+#if defined(OS_POSIX)
+#include <pthread.h>
+#endif
+
+namespace base {
+
+class ConditionVarImpl;
+class TimeDelta;
+
+class BASE_EXPORT ConditionVariable {
+ public:
+  // Construct a cv for use with ONLY one user lock.
+  explicit ConditionVariable(Lock* user_lock);
+
+  ~ConditionVariable();
+
+  // Wait() releases the caller's critical section atomically as it starts to
+  // sleep, and the reacquires it when it is signaled.
+  void Wait();
+  void TimedWait(const TimeDelta& max_time);
+
+  // Broadcast() revives all waiting threads.
+  void Broadcast();
+  // Signal() revives one waiting thread.
+  void Signal();
+
+ private:
+
+#if defined(OS_WIN)
+  ConditionVarImpl* impl_;
+#elif defined(OS_POSIX)
+  pthread_cond_t condition_;
+  pthread_mutex_t* user_mutex_;
+#if DCHECK_IS_ON()
+  base::Lock* user_lock_;     // Needed to adjust shadow lock state on wait.
+#endif
+
+#endif
+
+  DISALLOW_COPY_AND_ASSIGN(ConditionVariable);
+};
+
+}  // namespace base
+
+#endif  // BASE_SYNCHRONIZATION_CONDITION_VARIABLE_H_
diff --git a/security/sandbox/chromium/base/synchronization/condition_variable_posix.cc b/security/sandbox/chromium/base/synchronization/condition_variable_posix.cc
new file mode 100644
index 000000000..d86fd180e
--- /dev/null
+++ b/security/sandbox/chromium/base/synchronization/condition_variable_posix.cc
@@ -0,0 +1,137 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/synchronization/condition_variable.h"
+
+#include <errno.h>
+#include <stdint.h>
+#include <sys/time.h>
+
+#include "base/synchronization/lock.h"
+#include "base/threading/thread_restrictions.h"
+#include "base/time/time.h"
+#include "build/build_config.h"
+
+namespace base {
+
+ConditionVariable::ConditionVariable(Lock* user_lock)
+    : user_mutex_(user_lock->lock_.native_handle())
+#if DCHECK_IS_ON()
+    , user_lock_(user_lock)
+#endif
+{
+  int rv = 0;
+  // http://crbug.com/293736
+  // NaCl doesn't support monotonic clock based absolute deadlines.
+  // On older Android platform versions, it's supported through the
+  // non-standard pthread_cond_timedwait_monotonic_np. Newer platform
+  // versions have pthread_condattr_setclock.
+  // Mac can use relative time deadlines.
+#if !defined(OS_MACOSX) && !defined(OS_NACL) && \
+      !(defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC))
+  pthread_condattr_t attrs;
+  rv = pthread_condattr_init(&attrs);
+  DCHECK_EQ(0, rv);
+  pthread_condattr_setclock(&attrs, CLOCK_MONOTONIC);
+  rv = pthread_cond_init(&condition_, &attrs);
+  pthread_condattr_destroy(&attrs);
+#else
+  rv = pthread_cond_init(&condition_, NULL);
+#endif
+  DCHECK_EQ(0, rv);
+}
+
+ConditionVariable::~ConditionVariable() {
+#if defined(OS_MACOSX)
+  // This hack is necessary to avoid a fatal pthreads subsystem bug in the
+  // Darwin kernel. http://crbug.com/517681.
+  {
+    base::Lock lock;
+    base::AutoLock l(lock);
+    struct timespec ts;
+    ts.tv_sec = 0;
+    ts.tv_nsec = 1;
+    pthread_cond_timedwait_relative_np(&condition_, lock.lock_.native_handle(),
+                                       &ts);
+  }
+#endif
+
+  int rv = pthread_cond_destroy(&condition_);
+  DCHECK_EQ(0, rv);
+}
+
+void ConditionVariable::Wait() {
+  base::ThreadRestrictions::AssertWaitAllowed();
+#if DCHECK_IS_ON()
+  user_lock_->CheckHeldAndUnmark();
+#endif
+  int rv = pthread_cond_wait(&condition_, user_mutex_);
+  DCHECK_EQ(0, rv);
+#if DCHECK_IS_ON()
+  user_lock_->CheckUnheldAndMark();
+#endif
+}
+
+void ConditionVariable::TimedWait(const TimeDelta& max_time) {
+  base::ThreadRestrictions::AssertWaitAllowed();
+  int64_t usecs = max_time.InMicroseconds();
+  struct timespec relative_time;
+  relative_time.tv_sec = usecs / Time::kMicrosecondsPerSecond;
+  relative_time.tv_nsec =
+      (usecs % Time::kMicrosecondsPerSecond) * Time::kNanosecondsPerMicrosecond;
+
+#if DCHECK_IS_ON()
+  user_lock_->CheckHeldAndUnmark();
+#endif
+
+#if defined(OS_MACOSX)
+  int rv = pthread_cond_timedwait_relative_np(
+      &condition_, user_mutex_, &relative_time);
+#else
+  // The timeout argument to pthread_cond_timedwait is in absolute time.
+  struct timespec absolute_time;
+#if defined(OS_NACL)
+  // See comment in constructor for why this is different in NaCl.
+  struct timeval now;
+  gettimeofday(&now, NULL);
+  absolute_time.tv_sec = now.tv_sec;
+  absolute_time.tv_nsec = now.tv_usec * Time::kNanosecondsPerMicrosecond;
+#else
+  struct timespec now;
+  clock_gettime(CLOCK_MONOTONIC, &now);
+  absolute_time.tv_sec = now.tv_sec;
+  absolute_time.tv_nsec = now.tv_nsec;
+#endif
+
+  absolute_time.tv_sec += relative_time.tv_sec;
+  absolute_time.tv_nsec += relative_time.tv_nsec;
+  absolute_time.tv_sec += absolute_time.tv_nsec / Time::kNanosecondsPerSecond;
+  absolute_time.tv_nsec %= Time::kNanosecondsPerSecond;
+  DCHECK_GE(absolute_time.tv_sec, now.tv_sec);  // Overflow paranoia
+
+#if defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC)
+  int rv = pthread_cond_timedwait_monotonic_np(
+      &condition_, user_mutex_, &absolute_time);
+#else
+  int rv = pthread_cond_timedwait(&condition_, user_mutex_, &absolute_time);
+#endif  // OS_ANDROID && HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
+#endif  // OS_MACOSX
+
+  DCHECK(rv == 0 || rv == ETIMEDOUT);
+#if DCHECK_IS_ON()
+  user_lock_->CheckUnheldAndMark();
+#endif
+}
+
+void ConditionVariable::Broadcast() {
+  int rv = pthread_cond_broadcast(&condition_);
+  DCHECK_EQ(0, rv);
+}
+
+void ConditionVariable::Signal() {
+  int rv = pthread_cond_signal(&condition_);
+  DCHECK_EQ(0, rv);
+}
+
+}  // namespace base
diff --git a/security/sandbox/chromium/base/synchronization/lock.cc b/security/sandbox/chromium/base/synchronization/lock.cc
new file mode 100644
index 000000000..03297ada5
--- /dev/null
+++ b/security/sandbox/chromium/base/synchronization/lock.cc
@@ -0,0 +1,38 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file is used for debugging assertion support.  The Lock class
+// is functionally a wrapper around the LockImpl class, so the only
+// real intelligence in the class is in the debugging logic.
+
+#include "base/synchronization/lock.h"
+
+#if DCHECK_IS_ON()
+
+namespace base {
+
+Lock::Lock() : lock_() {
+}
+
+Lock::~Lock() {
+  DCHECK(owning_thread_ref_.is_null());
+}
+
+void Lock::AssertAcquired() const {
+  DCHECK(owning_thread_ref_ == PlatformThread::CurrentRef());
+}
+
+void Lock::CheckHeldAndUnmark() {
+  DCHECK(owning_thread_ref_ == PlatformThread::CurrentRef());
+  owning_thread_ref_ = PlatformThreadRef();
+}
+
+void Lock::CheckUnheldAndMark() {
+  DCHECK(owning_thread_ref_.is_null());
+  owning_thread_ref_ = PlatformThread::CurrentRef();
+}
+
+}  // namespace base
+
+#endif  // DCHECK_IS_ON()
diff --git a/security/sandbox/chromium/base/synchronization/lock.h b/security/sandbox/chromium/base/synchronization/lock.h
new file mode 100644
index 000000000..f7dd35dcc
--- /dev/null
+++ b/security/sandbox/chromium/base/synchronization/lock.h
@@ -0,0 +1,140 @@
+// Copyright (c) 2011 The Chromium 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 BASE_SYNCHRONIZATION_LOCK_H_
+#define BASE_SYNCHRONIZATION_LOCK_H_
+
+#include "base/base_export.h"
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/synchronization/lock_impl.h"
+#include "base/threading/platform_thread.h"
+#include "build/build_config.h"
+
+namespace base {
+
+// A convenient wrapper for an OS specific critical section.  The only real
+// intelligence in this class is in debug mode for the support for the
+// AssertAcquired() method.
+class BASE_EXPORT Lock {
+ public:
+#if !DCHECK_IS_ON()
+   // Optimized wrapper implementation
+  Lock() : lock_() {}
+  ~Lock() {}
+  void Acquire() { lock_.Lock(); }
+  void Release() { lock_.Unlock(); }
+
+  // If the lock is not held, take it and return true. If the lock is already
+  // held by another thread, immediately return false. This must not be called
+  // by a thread already holding the lock (what happens is undefined and an
+  // assertion may fail).
+  bool Try() { return lock_.Try(); }
+
+  // Null implementation if not debug.
+  void AssertAcquired() const {}
+#else
+  Lock();
+  ~Lock();
+
+  // NOTE: Although windows critical sections support recursive locks, we do not
+  // allow this, and we will commonly fire a DCHECK() if a thread attempts to
+  // acquire the lock a second time (while already holding it).
+  void Acquire() {
+    lock_.Lock();
+    CheckUnheldAndMark();
+  }
+  void Release() {
+    CheckHeldAndUnmark();
+    lock_.Unlock();
+  }
+
+  bool Try() {
+    bool rv = lock_.Try();
+    if (rv) {
+      CheckUnheldAndMark();
+    }
+    return rv;
+  }
+
+  void AssertAcquired() const;
+#endif  // DCHECK_IS_ON()
+
+#if defined(OS_POSIX)
+  // The posix implementation of ConditionVariable needs to be able
+  // to see our lock and tweak our debugging counters, as it releases
+  // and acquires locks inside of pthread_cond_{timed,}wait.
+  friend class ConditionVariable;
+#elif defined(OS_WIN)
+  // The Windows Vista implementation of ConditionVariable needs the
+  // native handle of the critical section.
+  friend class WinVistaCondVar;
+#endif
+
+ private:
+#if DCHECK_IS_ON()
+  // Members and routines taking care of locks assertions.
+  // Note that this checks for recursive locks and allows them
+  // if the variable is set.  This is allowed by the underlying implementation
+  // on windows but not on Posix, so we're doing unneeded checks on Posix.
+  // It's worth it to share the code.
+  void CheckHeldAndUnmark();
+  void CheckUnheldAndMark();
+
+  // All private data is implicitly protected by lock_.
+  // Be VERY careful to only access members under that lock.
+  base::PlatformThreadRef owning_thread_ref_;
+#endif  // DCHECK_IS_ON()
+
+  // Platform specific underlying lock implementation.
+  internal::LockImpl lock_;
+
+  DISALLOW_COPY_AND_ASSIGN(Lock);
+};
+
+// A helper class that acquires the given Lock while the AutoLock is in scope.
+class AutoLock {
+ public:
+  struct AlreadyAcquired {};
+
+  explicit AutoLock(Lock& lock) : lock_(lock) {
+    lock_.Acquire();
+  }
+
+  AutoLock(Lock& lock, const AlreadyAcquired&) : lock_(lock) {
+    lock_.AssertAcquired();
+  }
+
+  ~AutoLock() {
+    lock_.AssertAcquired();
+    lock_.Release();
+  }
+
+ private:
+  Lock& lock_;
+  DISALLOW_COPY_AND_ASSIGN(AutoLock);
+};
+
+// AutoUnlock is a helper that will Release() the |lock| argument in the
+// constructor, and re-Acquire() it in the destructor.
+class AutoUnlock {
+ public:
+  explicit AutoUnlock(Lock& lock) : lock_(lock) {
+    // We require our caller to have the lock.
+    lock_.AssertAcquired();
+    lock_.Release();
+  }
+
+  ~AutoUnlock() {
+    lock_.Acquire();
+  }
+
+ private:
+  Lock& lock_;
+  DISALLOW_COPY_AND_ASSIGN(AutoUnlock);
+};
+
+}  // namespace base
+
+#endif  // BASE_SYNCHRONIZATION_LOCK_H_
diff --git a/security/sandbox/chromium/base/synchronization/lock_impl.h b/security/sandbox/chromium/base/synchronization/lock_impl.h
new file mode 100644
index 000000000..ed85987b3
--- /dev/null
+++ b/security/sandbox/chromium/base/synchronization/lock_impl.h
@@ -0,0 +1,60 @@
+// Copyright (c) 2011 The Chromium 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 BASE_SYNCHRONIZATION_LOCK_IMPL_H_
+#define BASE_SYNCHRONIZATION_LOCK_IMPL_H_
+
+#include "base/base_export.h"
+#include "base/macros.h"
+#include "build/build_config.h"
+
+#if defined(OS_WIN)
+#include <windows.h>
+#elif defined(OS_POSIX)
+#include <pthread.h>
+#endif
+
+namespace base {
+namespace internal {
+
+// This class implements the underlying platform-specific spin-lock mechanism
+// used for the Lock class.  Most users should not use LockImpl directly, but
+// should instead use Lock.
+class BASE_EXPORT LockImpl {
+ public:
+#if defined(OS_WIN)
+  typedef CRITICAL_SECTION NativeHandle;
+#elif defined(OS_POSIX)
+  typedef pthread_mutex_t NativeHandle;
+#endif
+
+  LockImpl();
+  ~LockImpl();
+
+  // If the lock is not held, take it and return true.  If the lock is already
+  // held by something else, immediately return false.
+  bool Try();
+
+  // Take the lock, blocking until it is available if necessary.
+  void Lock();
+
+  // Release the lock.  This must only be called by the lock's holder: after
+  // a successful call to Try, or a call to Lock.
+  void Unlock();
+
+  // Return the native underlying lock.
+  // TODO(awalker): refactor lock and condition variables so that this is
+  // unnecessary.
+  NativeHandle* native_handle() { return &native_handle_; }
+
+ private:
+  NativeHandle native_handle_;
+
+  DISALLOW_COPY_AND_ASSIGN(LockImpl);
+};
+
+}  // namespace internal
+}  // namespace base
+
+#endif  // BASE_SYNCHRONIZATION_LOCK_IMPL_H_
diff --git a/security/sandbox/chromium/base/synchronization/lock_impl_posix.cc b/security/sandbox/chromium/base/synchronization/lock_impl_posix.cc
new file mode 100644
index 000000000..5619adaf5
--- /dev/null
+++ b/security/sandbox/chromium/base/synchronization/lock_impl_posix.cc
@@ -0,0 +1,55 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/synchronization/lock_impl.h"
+
+#include <errno.h>
+#include <string.h>
+
+#include "base/logging.h"
+
+namespace base {
+namespace internal {
+
+LockImpl::LockImpl() {
+#ifndef NDEBUG
+  // In debug, setup attributes for lock error checking.
+  pthread_mutexattr_t mta;
+  int rv = pthread_mutexattr_init(&mta);
+  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
+  rv = pthread_mutexattr_settype(&mta, PTHREAD_MUTEX_ERRORCHECK);
+  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
+  rv = pthread_mutex_init(&native_handle_, &mta);
+  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
+  rv = pthread_mutexattr_destroy(&mta);
+  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
+#else
+  // In release, go with the default lock attributes.
+  pthread_mutex_init(&native_handle_, NULL);
+#endif
+}
+
+LockImpl::~LockImpl() {
+  int rv = pthread_mutex_destroy(&native_handle_);
+  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
+}
+
+bool LockImpl::Try() {
+  int rv = pthread_mutex_trylock(&native_handle_);
+  DCHECK(rv == 0 || rv == EBUSY) << ". " << strerror(rv);
+  return rv == 0;
+}
+
+void LockImpl::Lock() {
+  int rv = pthread_mutex_lock(&native_handle_);
+  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
+}
+
+void LockImpl::Unlock() {
+  int rv = pthread_mutex_unlock(&native_handle_);
+  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
+}
+
+}  // namespace internal
+}  // namespace base
diff --git a/security/sandbox/chromium/base/synchronization/lock_impl_win.cc b/security/sandbox/chromium/base/synchronization/lock_impl_win.cc
new file mode 100644
index 000000000..fbc1bdd46
--- /dev/null
+++ b/security/sandbox/chromium/base/synchronization/lock_impl_win.cc
@@ -0,0 +1,36 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/synchronization/lock_impl.h"
+
+namespace base {
+namespace internal {
+
+LockImpl::LockImpl() {
+  // The second parameter is the spin count, for short-held locks it avoid the
+  // contending thread from going to sleep which helps performance greatly.
+  ::InitializeCriticalSectionAndSpinCount(&native_handle_, 2000);
+}
+
+LockImpl::~LockImpl() {
+  ::DeleteCriticalSection(&native_handle_);
+}
+
+bool LockImpl::Try() {
+  if (::TryEnterCriticalSection(&native_handle_) != FALSE) {
+    return true;
+  }
+  return false;
+}
+
+void LockImpl::Lock() {
+  ::EnterCriticalSection(&native_handle_);
+}
+
+void LockImpl::Unlock() {
+  ::LeaveCriticalSection(&native_handle_);
+}
+
+}  // namespace internal
+}  // namespace base
diff --git a/security/sandbox/chromium/base/synchronization/waitable_event.h b/security/sandbox/chromium/base/synchronization/waitable_event.h
new file mode 100644
index 000000000..b5d91d00b
--- /dev/null
+++ b/security/sandbox/chromium/base/synchronization/waitable_event.h
@@ -0,0 +1,189 @@
+// Copyright (c) 2012 The Chromium 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 BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_
+#define BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_
+
+#include <stddef.h>
+
+#include "base/base_export.h"
+#include "base/macros.h"
+#include "build/build_config.h"
+
+#if defined(OS_WIN)
+#include "base/win/scoped_handle.h"
+#endif
+
+#if defined(OS_POSIX)
+#include <list>
+#include <utility>
+#include "base/memory/ref_counted.h"
+#include "base/synchronization/lock.h"
+#endif
+
+namespace base {
+
+class TimeDelta;
+
+// A WaitableEvent can be a useful thread synchronization tool when you want to
+// allow one thread to wait for another thread to finish some work. For
+// non-Windows systems, this can only be used from within a single address
+// space.
+//
+// Use a WaitableEvent when you would otherwise use a Lock+ConditionVariable to
+// protect a simple boolean value.  However, if you find yourself using a
+// WaitableEvent in conjunction with a Lock to wait for a more complex state
+// change (e.g., for an item to be added to a queue), then you should probably
+// be using a ConditionVariable instead of a WaitableEvent.
+//
+// NOTE: On Windows, this class provides a subset of the functionality afforded
+// by a Windows event object.  This is intentional.  If you are writing Windows
+// specific code and you need other features of a Windows event, then you might
+// be better off just using an Windows event directly.
+class BASE_EXPORT WaitableEvent {
+ public:
+  // If manual_reset is true, then to set the event state to non-signaled, a
+  // consumer must call the Reset method.  If this parameter is false, then the
+  // system automatically resets the event state to non-signaled after a single
+  // waiting thread has been released.
+  WaitableEvent(bool manual_reset, bool initially_signaled);
+
+#if defined(OS_WIN)
+  // Create a WaitableEvent from an Event HANDLE which has already been
+  // created. This objects takes ownership of the HANDLE and will close it when
+  // deleted.
+  explicit WaitableEvent(win::ScopedHandle event_handle);
+#endif
+
+  ~WaitableEvent();
+
+  // Put the event in the un-signaled state.
+  void Reset();
+
+  // Put the event in the signaled state.  Causing any thread blocked on Wait
+  // to be woken up.
+  void Signal();
+
+  // Returns true if the event is in the signaled state, else false.  If this
+  // is not a manual reset event, then this test will cause a reset.
+  bool IsSignaled();
+
+  // Wait indefinitely for the event to be signaled. Wait's return "happens
+  // after" |Signal| has completed. This means that it's safe for a
+  // WaitableEvent to synchronise its own destruction, like this:
+  //
+  //   WaitableEvent *e = new WaitableEvent;
+  //   SendToOtherThread(e);
+  //   e->Wait();
+  //   delete e;
+  void Wait();
+
+  // Wait up until max_time has passed for the event to be signaled.  Returns
+  // true if the event was signaled.  If this method returns false, then it
+  // does not necessarily mean that max_time was exceeded.
+  //
+  // TimedWait can synchronise its own destruction like |Wait|.
+  bool TimedWait(const TimeDelta& max_time);
+
+#if defined(OS_WIN)
+  HANDLE handle() const { return handle_.Get(); }
+#endif
+
+  // Wait, synchronously, on multiple events.
+  //   waitables: an array of WaitableEvent pointers
+  //   count: the number of elements in @waitables
+  //
+  // returns: the index of a WaitableEvent which has been signaled.
+  //
+  // You MUST NOT delete any of the WaitableEvent objects while this wait is
+  // happening, however WaitMany's return "happens after" the |Signal| call
+  // that caused it has completed, like |Wait|.
+  static size_t WaitMany(WaitableEvent** waitables, size_t count);
+
+  // For asynchronous waiting, see WaitableEventWatcher
+
+  // This is a private helper class. It's here because it's used by friends of
+  // this class (such as WaitableEventWatcher) to be able to enqueue elements
+  // of the wait-list
+  class Waiter {
+   public:
+    // Signal the waiter to wake up.
+    //
+    // Consider the case of a Waiter which is in multiple WaitableEvent's
+    // wait-lists. Each WaitableEvent is automatic-reset and two of them are
+    // signaled at the same time. Now, each will wake only the first waiter in
+    // the wake-list before resetting. However, if those two waiters happen to
+    // be the same object (as can happen if another thread didn't have a chance
+    // to dequeue the waiter from the other wait-list in time), two auto-resets
+    // will have happened, but only one waiter has been signaled!
+    //
+    // Because of this, a Waiter may "reject" a wake by returning false. In
+    // this case, the auto-reset WaitableEvent shouldn't act as if anything has
+    // been notified.
+    virtual bool Fire(WaitableEvent* signaling_event) = 0;
+
+    // Waiters may implement this in order to provide an extra condition for
+    // two Waiters to be considered equal. In WaitableEvent::Dequeue, if the
+    // pointers match then this function is called as a final check. See the
+    // comments in ~Handle for why.
+    virtual bool Compare(void* tag) = 0;
+
+   protected:
+    virtual ~Waiter() {}
+  };
+
+ private:
+  friend class WaitableEventWatcher;
+
+#if defined(OS_WIN)
+  win::ScopedHandle handle_;
+#else
+  // On Windows, one can close a HANDLE which is currently being waited on. The
+  // MSDN documentation says that the resulting behaviour is 'undefined', but
+  // it doesn't crash. However, if we were to include the following members
+  // directly then, on POSIX, one couldn't use WaitableEventWatcher to watch an
+  // event which gets deleted. This mismatch has bitten us several times now,
+  // so we have a kernel of the WaitableEvent, which is reference counted.
+  // WaitableEventWatchers may then take a reference and thus match the Windows
+  // behaviour.
+  struct WaitableEventKernel :
+      public RefCountedThreadSafe<WaitableEventKernel> {
+   public:
+    WaitableEventKernel(bool manual_reset, bool initially_signaled);
+
+    bool Dequeue(Waiter* waiter, void* tag);
+
+    base::Lock lock_;
+    const bool manual_reset_;
+    bool signaled_;
+    std::list<Waiter*> waiters_;
+
+   private:
+    friend class RefCountedThreadSafe<WaitableEventKernel>;
+    ~WaitableEventKernel();
+  };
+
+  typedef std::pair<WaitableEvent*, size_t> WaiterAndIndex;
+
+  // When dealing with arrays of WaitableEvent*, we want to sort by the address
+  // of the WaitableEvent in order to have a globally consistent locking order.
+  // In that case we keep them, in sorted order, in an array of pairs where the
+  // second element is the index of the WaitableEvent in the original,
+  // unsorted, array.
+  static size_t EnqueueMany(WaiterAndIndex* waitables,
+                            size_t count, Waiter* waiter);
+
+  bool SignalAll();
+  bool SignalOne();
+  void Enqueue(Waiter* waiter);
+
+  scoped_refptr<WaitableEventKernel> kernel_;
+#endif
+
+  DISALLOW_COPY_AND_ASSIGN(WaitableEvent);
+};
+
+}  // namespace base
+
+#endif  // BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_
diff --git a/security/sandbox/chromium/base/synchronization/waitable_event_posix.cc b/security/sandbox/chromium/base/synchronization/waitable_event_posix.cc
new file mode 100644
index 000000000..64d4376fe
--- /dev/null
+++ b/security/sandbox/chromium/base/synchronization/waitable_event_posix.cc
@@ -0,0 +1,417 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <stddef.h>
+
+#include <algorithm>
+#include <vector>
+
+#include "base/logging.h"
+#include "base/synchronization/condition_variable.h"
+#include "base/synchronization/lock.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/threading/thread_restrictions.h"
+
+// -----------------------------------------------------------------------------
+// A WaitableEvent on POSIX is implemented as a wait-list. Currently we don't
+// support cross-process events (where one process can signal an event which
+// others are waiting on). Because of this, we can avoid having one thread per
+// listener in several cases.
+//
+// The WaitableEvent maintains a list of waiters, protected by a lock. Each
+// waiter is either an async wait, in which case we have a Task and the
+// MessageLoop to run it on, or a blocking wait, in which case we have the
+// condition variable to signal.
+//
+// Waiting involves grabbing the lock and adding oneself to the wait list. Async
+// waits can be canceled, which means grabbing the lock and removing oneself
+// from the list.
+//
+// Waiting on multiple events is handled by adding a single, synchronous wait to
+// the wait-list of many events. An event passes a pointer to itself when
+// firing a waiter and so we can store that pointer to find out which event
+// triggered.
+// -----------------------------------------------------------------------------
+
+namespace base {
+
+// -----------------------------------------------------------------------------
+// This is just an abstract base class for waking the two types of waiters
+// -----------------------------------------------------------------------------
+WaitableEvent::WaitableEvent(bool manual_reset, bool initially_signaled)
+    : kernel_(new WaitableEventKernel(manual_reset, initially_signaled)) {
+}
+
+WaitableEvent::~WaitableEvent() {
+}
+
+void WaitableEvent::Reset() {
+  base::AutoLock locked(kernel_->lock_);
+  kernel_->signaled_ = false;
+}
+
+void WaitableEvent::Signal() {
+  base::AutoLock locked(kernel_->lock_);
+
+  if (kernel_->signaled_)
+    return;
+
+  if (kernel_->manual_reset_) {
+    SignalAll();
+    kernel_->signaled_ = true;
+  } else {
+    // In the case of auto reset, if no waiters were woken, we remain
+    // signaled.
+    if (!SignalOne())
+      kernel_->signaled_ = true;
+  }
+}
+
+bool WaitableEvent::IsSignaled() {
+  base::AutoLock locked(kernel_->lock_);
+
+  const bool result = kernel_->signaled_;
+  if (result && !kernel_->manual_reset_)
+    kernel_->signaled_ = false;
+  return result;
+}
+
+// -----------------------------------------------------------------------------
+// Synchronous waits
+
+// -----------------------------------------------------------------------------
+// This is a synchronous waiter. The thread is waiting on the given condition
+// variable and the fired flag in this object.
+// -----------------------------------------------------------------------------
+class SyncWaiter : public WaitableEvent::Waiter {
+ public:
+  SyncWaiter()
+      : fired_(false),
+        signaling_event_(NULL),
+        lock_(),
+        cv_(&lock_) {
+  }
+
+  bool Fire(WaitableEvent* signaling_event) override {
+    base::AutoLock locked(lock_);
+
+    if (fired_)
+      return false;
+
+    fired_ = true;
+    signaling_event_ = signaling_event;
+
+    cv_.Broadcast();
+
+    // Unlike AsyncWaiter objects, SyncWaiter objects are stack-allocated on
+    // the blocking thread's stack.  There is no |delete this;| in Fire.  The
+    // SyncWaiter object is destroyed when it goes out of scope.
+
+    return true;
+  }
+
+  WaitableEvent* signaling_event() const {
+    return signaling_event_;
+  }
+
+  // ---------------------------------------------------------------------------
+  // These waiters are always stack allocated and don't delete themselves. Thus
+  // there's no problem and the ABA tag is the same as the object pointer.
+  // ---------------------------------------------------------------------------
+  bool Compare(void* tag) override { return this == tag; }
+
+  // ---------------------------------------------------------------------------
+  // Called with lock held.
+  // ---------------------------------------------------------------------------
+  bool fired() const {
+    return fired_;
+  }
+
+  // ---------------------------------------------------------------------------
+  // During a TimedWait, we need a way to make sure that an auto-reset
+  // WaitableEvent doesn't think that this event has been signaled between
+  // unlocking it and removing it from the wait-list. Called with lock held.
+  // ---------------------------------------------------------------------------
+  void Disable() {
+    fired_ = true;
+  }
+
+  base::Lock* lock() {
+    return &lock_;
+  }
+
+  base::ConditionVariable* cv() {
+    return &cv_;
+  }
+
+ private:
+  bool fired_;
+  WaitableEvent* signaling_event_;  // The WaitableEvent which woke us
+  base::Lock lock_;
+  base::ConditionVariable cv_;
+};
+
+void WaitableEvent::Wait() {
+  bool result = TimedWait(TimeDelta::FromSeconds(-1));
+  DCHECK(result) << "TimedWait() should never fail with infinite timeout";
+}
+
+bool WaitableEvent::TimedWait(const TimeDelta& max_time) {
+  base::ThreadRestrictions::AssertWaitAllowed();
+  const TimeTicks end_time(TimeTicks::Now() + max_time);
+  const bool finite_time = max_time.ToInternalValue() >= 0;
+
+  kernel_->lock_.Acquire();
+  if (kernel_->signaled_) {
+    if (!kernel_->manual_reset_) {
+      // In this case we were signaled when we had no waiters. Now that
+      // someone has waited upon us, we can automatically reset.
+      kernel_->signaled_ = false;
+    }
+
+    kernel_->lock_.Release();
+    return true;
+  }
+
+  SyncWaiter sw;
+  sw.lock()->Acquire();
+
+  Enqueue(&sw);
+  kernel_->lock_.Release();
+  // We are violating locking order here by holding the SyncWaiter lock but not
+  // the WaitableEvent lock. However, this is safe because we don't lock @lock_
+  // again before unlocking it.
+
+  for (;;) {
+    const TimeTicks current_time(TimeTicks::Now());
+
+    if (sw.fired() || (finite_time && current_time >= end_time)) {
+      const bool return_value = sw.fired();
+
+      // We can't acquire @lock_ before releasing the SyncWaiter lock (because
+      // of locking order), however, in between the two a signal could be fired
+      // and @sw would accept it, however we will still return false, so the
+      // signal would be lost on an auto-reset WaitableEvent. Thus we call
+      // Disable which makes sw::Fire return false.
+      sw.Disable();
+      sw.lock()->Release();
+
+      // This is a bug that has been enshrined in the interface of
+      // WaitableEvent now: |Dequeue| is called even when |sw.fired()| is true,
+      // even though it'll always return false in that case. However, taking
+      // the lock ensures that |Signal| has completed before we return and
+      // means that a WaitableEvent can synchronise its own destruction.
+      kernel_->lock_.Acquire();
+      kernel_->Dequeue(&sw, &sw);
+      kernel_->lock_.Release();
+
+      return return_value;
+    }
+
+    if (finite_time) {
+      const TimeDelta max_wait(end_time - current_time);
+      sw.cv()->TimedWait(max_wait);
+    } else {
+      sw.cv()->Wait();
+    }
+  }
+}
+
+// -----------------------------------------------------------------------------
+// Synchronous waiting on multiple objects.
+
+static bool  // StrictWeakOrdering
+cmp_fst_addr(const std::pair<WaitableEvent*, unsigned> &a,
+             const std::pair<WaitableEvent*, unsigned> &b) {
+  return a.first < b.first;
+}
+
+// static
+size_t WaitableEvent::WaitMany(WaitableEvent** raw_waitables,
+                               size_t count) {
+  base::ThreadRestrictions::AssertWaitAllowed();
+  DCHECK(count) << "Cannot wait on no events";
+
+  // We need to acquire the locks in a globally consistent order. Thus we sort
+  // the array of waitables by address. We actually sort a pairs so that we can
+  // map back to the original index values later.
+  std::vector<std::pair<WaitableEvent*, size_t> > waitables;
+  waitables.reserve(count);
+  for (size_t i = 0; i < count; ++i)
+    waitables.push_back(std::make_pair(raw_waitables[i], i));
+
+  DCHECK_EQ(count, waitables.size());
+
+  sort(waitables.begin(), waitables.end(), cmp_fst_addr);
+
+  // The set of waitables must be distinct. Since we have just sorted by
+  // address, we can check this cheaply by comparing pairs of consecutive
+  // elements.
+  for (size_t i = 0; i < waitables.size() - 1; ++i) {
+    DCHECK(waitables[i].first != waitables[i+1].first);
+  }
+
+  SyncWaiter sw;
+
+  const size_t r = EnqueueMany(&waitables[0], count, &sw);
+  if (r) {
+    // One of the events is already signaled. The SyncWaiter has not been
+    // enqueued anywhere. EnqueueMany returns the count of remaining waitables
+    // when the signaled one was seen, so the index of the signaled event is
+    // @count - @r.
+    return waitables[count - r].second;
+  }
+
+  // At this point, we hold the locks on all the WaitableEvents and we have
+  // enqueued our waiter in them all.
+  sw.lock()->Acquire();
+    // Release the WaitableEvent locks in the reverse order
+    for (size_t i = 0; i < count; ++i) {
+      waitables[count - (1 + i)].first->kernel_->lock_.Release();
+    }
+
+    for (;;) {
+      if (sw.fired())
+        break;
+
+      sw.cv()->Wait();
+    }
+  sw.lock()->Release();
+
+  // The address of the WaitableEvent which fired is stored in the SyncWaiter.
+  WaitableEvent *const signaled_event = sw.signaling_event();
+  // This will store the index of the raw_waitables which fired.
+  size_t signaled_index = 0;
+
+  // Take the locks of each WaitableEvent in turn (except the signaled one) and
+  // remove our SyncWaiter from the wait-list
+  for (size_t i = 0; i < count; ++i) {
+    if (raw_waitables[i] != signaled_event) {
+      raw_waitables[i]->kernel_->lock_.Acquire();
+        // There's no possible ABA issue with the address of the SyncWaiter here
+        // because it lives on the stack. Thus the tag value is just the pointer
+        // value again.
+        raw_waitables[i]->kernel_->Dequeue(&sw, &sw);
+      raw_waitables[i]->kernel_->lock_.Release();
+    } else {
+      // By taking this lock here we ensure that |Signal| has completed by the
+      // time we return, because |Signal| holds this lock. This matches the
+      // behaviour of |Wait| and |TimedWait|.
+      raw_waitables[i]->kernel_->lock_.Acquire();
+      raw_waitables[i]->kernel_->lock_.Release();
+      signaled_index = i;
+    }
+  }
+
+  return signaled_index;
+}
+
+// -----------------------------------------------------------------------------
+// If return value == 0:
+//   The locks of the WaitableEvents have been taken in order and the Waiter has
+//   been enqueued in the wait-list of each. None of the WaitableEvents are
+//   currently signaled
+// else:
+//   None of the WaitableEvent locks are held. The Waiter has not been enqueued
+//   in any of them and the return value is the index of the first WaitableEvent
+//   which was signaled, from the end of the array.
+// -----------------------------------------------------------------------------
+// static
+size_t WaitableEvent::EnqueueMany
+    (std::pair<WaitableEvent*, size_t>* waitables,
+     size_t count, Waiter* waiter) {
+  if (!count)
+    return 0;
+
+  waitables[0].first->kernel_->lock_.Acquire();
+    if (waitables[0].first->kernel_->signaled_) {
+      if (!waitables[0].first->kernel_->manual_reset_)
+        waitables[0].first->kernel_->signaled_ = false;
+      waitables[0].first->kernel_->lock_.Release();
+      return count;
+    }
+
+    const size_t r = EnqueueMany(waitables + 1, count - 1, waiter);
+    if (r) {
+      waitables[0].first->kernel_->lock_.Release();
+    } else {
+      waitables[0].first->Enqueue(waiter);
+    }
+
+    return r;
+}
+
+// -----------------------------------------------------------------------------
+
+
+// -----------------------------------------------------------------------------
+// Private functions...
+
+WaitableEvent::WaitableEventKernel::WaitableEventKernel(bool manual_reset,
+                                                        bool initially_signaled)
+    : manual_reset_(manual_reset),
+      signaled_(initially_signaled) {
+}
+
+WaitableEvent::WaitableEventKernel::~WaitableEventKernel() {
+}
+
+// -----------------------------------------------------------------------------
+// Wake all waiting waiters. Called with lock held.
+// -----------------------------------------------------------------------------
+bool WaitableEvent::SignalAll() {
+  bool signaled_at_least_one = false;
+
+  for (std::list<Waiter*>::iterator
+       i = kernel_->waiters_.begin(); i != kernel_->waiters_.end(); ++i) {
+    if ((*i)->Fire(this))
+      signaled_at_least_one = true;
+  }
+
+  kernel_->waiters_.clear();
+  return signaled_at_least_one;
+}
+
+// ---------------------------------------------------------------------------
+// Try to wake a single waiter. Return true if one was woken. Called with lock
+// held.
+// ---------------------------------------------------------------------------
+bool WaitableEvent::SignalOne() {
+  for (;;) {
+    if (kernel_->waiters_.empty())
+      return false;
+
+    const bool r = (*kernel_->waiters_.begin())->Fire(this);
+    kernel_->waiters_.pop_front();
+    if (r)
+      return true;
+  }
+}
+
+// -----------------------------------------------------------------------------
+// Add a waiter to the list of those waiting. Called with lock held.
+// -----------------------------------------------------------------------------
+void WaitableEvent::Enqueue(Waiter* waiter) {
+  kernel_->waiters_.push_back(waiter);
+}
+
+// -----------------------------------------------------------------------------
+// Remove a waiter from the list of those waiting. Return true if the waiter was
+// actually removed. Called with lock held.
+// -----------------------------------------------------------------------------
+bool WaitableEvent::WaitableEventKernel::Dequeue(Waiter* waiter, void* tag) {
+  for (std::list<Waiter*>::iterator
+       i = waiters_.begin(); i != waiters_.end(); ++i) {
+    if (*i == waiter && (*i)->Compare(tag)) {
+      waiters_.erase(i);
+      return true;
+    }
+  }
+
+  return false;
+}
+
+// -----------------------------------------------------------------------------
+
+}  // namespace base