Made MessagePump a non-thread safe class.

base/message_loop/message_loop.cc

Index: base/message_loop/message_loop.cc
diff --git a/base/message_loop/message_loop.cc b/base/message_loop/message_loop.cc
index bd3542a664a261fc917ca77894dca4f4aa19f121..d2eafbd8489fd32c0822ebe9b740c2f560f1c3a2 100644
--- a/base/message_loop/message_loop.cc
+++ b/base/message_loop/message_loop.cc
@@ -13,7 +13,6 @@
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/message_loop/message_loop_proxy_impl.h"
 #include "base/message_loop/message_pump_default.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/statistics_recorder.h"
@@ -89,14 +88,6 @@ bool enable_histogrammer_ = false;
 
 MessageLoop::MessagePumpFactory* message_pump_for_ui_factory_ = NULL;
 
-// Create a process-wide unique ID to represent this task in trace events. This
-// will be mangled with a Process ID hash to reduce the likelyhood of colliding
-// with MessageLoop pointers on other processes.
-uint64 GetTaskTraceID(const PendingTask& task, MessageLoop* loop) {
-  return (static_cast<uint64>(task.sequence_num) << 32) |
-         static_cast<uint64>(reinterpret_cast<intptr_t>(loop));
-}
-
 // Returns true if MessagePump::ScheduleWork() must be called one
 // time for every task that is added to the MessageLoop incoming queue.
 bool AlwaysNotifyPump(MessageLoop::Type type) {
@@ -146,18 +137,19 @@ MessageLoop::DestructionObserver::~DestructionObserver() {
 
 MessageLoop::MessageLoop(Type type)
     : type_(type),
-      nestable_tasks_allowed_(true),
       exception_restoration_(false),
-      message_histogram_(NULL),
-      run_loop_(NULL),
+      nestable_tasks_allowed_(true),
 #if defined(OS_WIN)
       os_modal_loop_(false),
 #endif  // OS_WIN
-      next_sequence_num_(0) {
+      message_histogram_(NULL),
+      run_loop_(NULL) {
   DCHECK(!current()) << "should only have one message loop per thread";
   lazy_tls_ptr.Pointer()->Set(this);
 
-  message_loop_proxy_ = new MessageLoopProxyImpl();
+  incoming_task_queue_ = new internal::IncomingTaskQueue(this);
+  message_loop_proxy_ =
+      new internal::MessageLoopProxyImpl(incoming_task_queue_);
   thread_task_runner_handle_.reset(
       new ThreadTaskRunnerHandle(message_loop_proxy_));
 
@@ -177,7 +169,7 @@ MessageLoop::MessageLoop(Type type)
 #define MESSAGE_PUMP_UI NULL
 // ipc_channel_nacl.cc uses a worker thread to do socket reads currently, and
 // doesn't require extra support for watching file descriptors.
-#define MESSAGE_PUMP_IO new MessagePumpDefault();
+#define MESSAGE_PUMP_IO new MessagePumpDefault()
 #elif defined(OS_POSIX)  // POSIX but not MACOSX.
 #define MESSAGE_PUMP_UI new MessagePumpForUI()
 #define MESSAGE_PUMP_IO new MessagePumpLibevent()
@@ -187,14 +179,14 @@ MessageLoop::MessageLoop(Type type)
 
   if (type_ == TYPE_UI) {
     if (message_pump_for_ui_factory_)
-      pump_ = message_pump_for_ui_factory_();
+      pump_.reset(message_pump_for_ui_factory_());
     else
-      pump_ = MESSAGE_PUMP_UI;
+      pump_.reset(MESSAGE_PUMP_UI);
   } else if (type_ == TYPE_IO) {
-    pump_ = MESSAGE_PUMP_IO;
+    pump_.reset(MESSAGE_PUMP_IO);
   } else {
     DCHECK_EQ(TYPE_DEFAULT, type_);
-    pump_ = new MessagePumpDefault();
+    pump_.reset(new MessagePumpDefault());
   }
 }
 
@@ -226,23 +218,13 @@ MessageLoop::~MessageLoop() {
 
   thread_task_runner_handle_.reset();
 
-  // Tell the message_loop_proxy that we are dying.
-  static_cast<MessageLoopProxyImpl*>(message_loop_proxy_.get())->
-      WillDestroyCurrentMessageLoop();
+  // Tell the incoming queue that we are dying.
+  incoming_task_queue_->WillDestroyCurrentMessageLoop();
+  incoming_task_queue_ = NULL;
   message_loop_proxy_ = NULL;
 
   // OK, now make it so that no one can find us.
   lazy_tls_ptr.Pointer()->Set(NULL);
-
-#if defined(OS_WIN)
-  // If we left the high-resolution timer activated, deactivate it now.
-  // Doing this is not-critical, it is mainly to make sure we track
-  // the high resolution timer activations properly in our unit tests.
-  if (!high_resolution_timer_expiration_.is_null()) {
-    Time::ActivateHighResolutionTimer(false);
-    high_resolution_timer_expiration_ = TimeTicks();
-  }
-#endif
 }
 
 // static
@@ -283,18 +265,14 @@ void MessageLoop::PostTask(
     const tracked_objects::Location& from_here,
     const Closure& task) {
   DCHECK(!task.is_null()) << from_here.ToString();
-  PendingTask pending_task(
-      from_here, task, CalculateDelayedRuntime(TimeDelta()), true);
-  AddToIncomingQueue(&pending_task, false);
+  incoming_task_queue_->AddToIncomingQueue(from_here, task, TimeDelta(), true);
 }
 
 bool MessageLoop::TryPostTask(
     const tracked_objects::Location& from_here,
     const Closure& task) {
   DCHECK(!task.is_null()) << from_here.ToString();
-  PendingTask pending_task(
-      from_here, task, CalculateDelayedRuntime(TimeDelta()), true);
-  return AddToIncomingQueue(&pending_task, true);
+  return incoming_task_queue_->TryAddToIncomingQueue(from_here, task);
 }
 
 void MessageLoop::PostDelayedTask(
@@ -302,18 +280,14 @@ void MessageLoop::PostDelayedTask(
     const Closure& task,
     TimeDelta delay) {
   DCHECK(!task.is_null()) << from_here.ToString();
-  PendingTask pending_task(
-      from_here, task, CalculateDelayedRuntime(delay), true);
-  AddToIncomingQueue(&pending_task, false);
+  incoming_task_queue_->AddToIncomingQueue(from_here, task, delay, true);
 }
 
 void MessageLoop::PostNonNestableTask(
     const tracked_objects::Location& from_here,
     const Closure& task) {
   DCHECK(!task.is_null()) << from_here.ToString();
-  PendingTask pending_task(
-      from_here, task, CalculateDelayedRuntime(TimeDelta()), false);
-  AddToIncomingQueue(&pending_task, false);
+  incoming_task_queue_->AddToIncomingQueue(from_here, task, TimeDelta(), false);
 }
 
 void MessageLoop::PostNonNestableDelayedTask(
@@ -321,9 +295,7 @@ void MessageLoop::PostNonNestableDelayedTask(
     const Closure& task,
     TimeDelta delay) {
   DCHECK(!task.is_null()) << from_here.ToString();
-  PendingTask pending_task(
-      from_here, task, CalculateDelayedRuntime(delay), false);
-  AddToIncomingQueue(&pending_task, false);
+  incoming_task_queue_->AddToIncomingQueue(from_here, task, delay, false);
 }
 
 void MessageLoop::Run() {
@@ -395,17 +367,26 @@ void MessageLoop::RemoveTaskObserver(TaskObserver* task_observer) {
   task_observers_.RemoveObserver(task_observer);
 }
 
-void MessageLoop::AssertIdle() const {
-  // We only check |incoming_queue_|, since we don't want to lock |work_queue_|.
-  AutoLock lock(incoming_queue_lock_);
-  DCHECK(incoming_queue_.empty());
-}
-
 bool MessageLoop::is_running() const {
   DCHECK_EQ(this, current());
   return run_loop_ != NULL;
 }
 
+bool MessageLoop::IsHighResolutionTimerEnabledForTesting() {
+  return incoming_task_queue_->IsHighResolutionTimerEnabledForTesting();
+}
+
+bool MessageLoop::IsIdleForTesting() {
+  // We only check the imcoming queue|, since we don't want to lock the work
+  // queue.
+  return incoming_task_queue_->IsIdleForTesting();
+}
+
+void MessageLoop::LockWaitUnLockForTesting(WaitableEvent* caller_wait,
+                                           WaitableEvent* caller_signal) {
+  incoming_task_queue_->LockWaitUnLockForTesting(caller_wait, caller_signal);
+}
+
 //------------------------------------------------------------------------------
 
 // Runs the loop in two different SEH modes:
@@ -470,7 +451,7 @@ void MessageLoop::RunTask(const PendingTask& pending_task) {
       tracked_objects::ThreadData::NowForStartOfRun(pending_task.birth_tally);
 
   TRACE_EVENT_FLOW_END1("task", "MessageLoop::PostTask",
-      TRACE_ID_MANGLE(GetTaskTraceID(pending_task, this)),
+      TRACE_ID_MANGLE(GetTaskTraceID(pending_task)),
       "queue_duration",
       (start_time - pending_task.EffectiveTimePosted()).InMilliseconds());
   TRACE_EVENT2("task", "MessageLoop::RunTask",
@@ -523,24 +504,6 @@ void MessageLoop::AddToDelayedWorkQueue(const PendingTask& pending_task) {
   delayed_work_queue_.push(pending_task);
 }
 
-void MessageLoop::ReloadWorkQueue() {
-  // We can improve performance of our loading tasks from incoming_queue_ to
-  // work_queue_ by waiting until the last minute (work_queue_ is empty) to
-  // load.  That reduces the number of locks-per-task significantly when our
-  // queues get large.
-  if (!work_queue_.empty())
-    return;  // Wait till we *really* need to lock and load.
-
-  // Acquire all we can from the inter-thread queue with one lock acquisition.
-  {
-    AutoLock lock(incoming_queue_lock_);
-    if (incoming_queue_.empty())
-      return;
-    incoming_queue_.Swap(&work_queue_);  // Constant time
-    DCHECK(incoming_queue_.empty());
-  }
-}
-
 bool MessageLoop::DeletePendingTasks() {
   bool did_work = !work_queue_.empty();
   while (!work_queue_.empty()) {
@@ -570,87 +533,25 @@ bool MessageLoop::DeletePendingTasks() {
   return did_work;
 }
 
-TimeTicks MessageLoop::CalculateDelayedRuntime(TimeDelta delay) {
-  TimeTicks delayed_run_time;
-  if (delay > TimeDelta()) {
-    delayed_run_time = TimeTicks::Now() + delay;
-
-#if defined(OS_WIN)
-    if (high_resolution_timer_expiration_.is_null()) {
-      // Windows timers are granular to 15.6ms.  If we only set high-res
-      // timers for those under 15.6ms, then a 18ms timer ticks at ~32ms,
-      // which as a percentage is pretty inaccurate.  So enable high
-      // res timers for any timer which is within 2x of the granularity.
-      // This is a tradeoff between accuracy and power management.
-      bool needs_high_res_timers = delay.InMilliseconds() <
-          (2 * Time::kMinLowResolutionThresholdMs);
-      if (needs_high_res_timers) {
-        if (Time::ActivateHighResolutionTimer(true)) {
-          high_resolution_timer_expiration_ = TimeTicks::Now() +
-              TimeDelta::FromMilliseconds(kHighResolutionTimerModeLeaseTimeMs);
-        }
-      }
-    }
-#endif
-  } else {
-    DCHECK_EQ(delay.InMilliseconds(), 0) << "delay should not be negative";
-  }
-
-#if defined(OS_WIN)
-  if (!high_resolution_timer_expiration_.is_null()) {
-    if (TimeTicks::Now() > high_resolution_timer_expiration_) {
-      Time::ActivateHighResolutionTimer(false);
-      high_resolution_timer_expiration_ = TimeTicks();
-    }
-  }
-#endif
-
-  return delayed_run_time;
+uint64 MessageLoop::GetTaskTraceID(const PendingTask& task) {
+  return (static_cast<uint64>(task.sequence_num) << 32) |
+         static_cast<uint64>(reinterpret_cast<intptr_t>(this));
 }
 
-// Possibly called on a background thread!
-bool MessageLoop::AddToIncomingQueue(PendingTask* pending_task,
-                                     bool use_try_lock) {
-  // Warning: Don't try to short-circuit, and handle this thread's tasks more
-  // directly, as it could starve handling of foreign threads.  Put every task
-  // into this queue.
-
-  scoped_refptr<MessagePump> pump;
-  {
-    if (use_try_lock) {
-      if (!incoming_queue_lock_.Try()) {
-        pending_task->task.Reset();
-        return false;
-      }
-    } else {
-      incoming_queue_lock_.Acquire();
-    }
-    AutoLock locked(incoming_queue_lock_, AutoLock::AlreadyAcquired());
-    // Initialize the sequence number. The sequence number is used for delayed
-    // tasks (to faciliate FIFO sorting when two tasks have the same
-    // delayed_run_time value) and for identifying the task in about:tracing.
-    pending_task->sequence_num = next_sequence_num_++;
-
-    TRACE_EVENT_FLOW_BEGIN0("task", "MessageLoop::PostTask",
-        TRACE_ID_MANGLE(GetTaskTraceID(*pending_task, this)));
-
-    bool was_empty = incoming_queue_.empty();
-    incoming_queue_.push(*pending_task);
-    pending_task->task.Reset();
-    // The Android UI message loop needs to get notified each time
-    // a task is added to the incoming queue.
-    if (!was_empty && !AlwaysNotifyPump(type_))
-      return true;  // Someone else should have started the sub-pump.
-
-    pump = pump_;
-  }
-  // Since the incoming_queue_ may contain a task that destroys this message
-  // loop, we cannot exit incoming_queue_lock_ until we are done with |this|.
-  // We use a stack-based reference to the message pump so that we can call
-  // ScheduleWork outside of incoming_queue_lock_.
+void MessageLoop::ReloadWorkQueue() {
+  // We can improve performance of our loading tasks from the incoming queue to
+  // |*work_queue| by waiting until the last minute (|*work_queue| is empty) to
+  // load. That reduces the number of locks-per-task significantly when our
+  // queues get large.
+  if (work_queue_.empty())
+    incoming_task_queue_->ReloadWorkQueue(&work_queue_);
+}
 
-  pump->ScheduleWork();
-  return true;
+void MessageLoop::ScheduleWork(bool was_empty) {
+  // The Android UI message loop needs to get notified each time
+  // a task is added to the incoming queue.
+  if (was_empty || AlwaysNotifyPump(type_))
+    pump_->ScheduleWork();
 }
 
 //------------------------------------------------------------------------------