- Add assertions in MutexLocker/MonitorLocker to ensure that the code enclosed

runtime/vm/os_thread.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_OS_THREAD_H_
 #define VM_OS_THREAD_H_
 
 #include "platform/globals.h"
 #include "vm/allocation.h"
 #include "vm/globals.h"
@@ skipping 249 matching lines @@
   OSThread* next_;
 };
 
 
 class Mutex {
  public:
   Mutex();
   ~Mutex();
 
   void Lock();
-  bool TryLock();
+  bool TryLock();  // Returns false if lock is busy and locking failed.
   void Unlock();
 
 #if defined(DEBUG)
   bool IsOwnedByCurrentThread() const {
     return owner_ == OSThread::GetCurrentThreadId();
   }
 #else
   bool IsOwnedByCurrentThread() const {
     UNREACHABLE();
     return false;
@@ skipping 15 matching lines @@
   enum WaitResult {
     kNotified,
     kTimedOut
   };
 
   static const int64_t kNoTimeout = 0;
 
   Monitor();
   ~Monitor();
 
+  bool TryEnter();  // Returns false if lock is busy and locking failed.
   void Enter();
   void Exit();
 
   // Wait for notification or timeout.
   WaitResult Wait(int64_t millis);
   WaitResult WaitMicros(int64_t micros);
 
   // Notify waiting threads.
   void Notify();
   void NotifyAll();
@@ skipping 16 matching lines @@
 #endif  // defined(DEBUG)
 
   DISALLOW_COPY_AND_ASSIGN(Monitor);
 };
 
 
 }  // namespace dart
 
 
 #endif  // VM_OS_THREAD_H_