Adds some CHECKs to MessagePumpMojo

mojo/common/message_pump_mojo.cc

 // Copyright 2013 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 "mojo/common/message_pump_mojo.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/debug/alias.h"
 #include "base/logging.h"
 #include "base/time/time.h"
 #include "mojo/common/message_pump_mojo_handler.h"
 #include "mojo/common/time_helper.h"
 
 namespace mojo {
 namespace common {
+namespace {
+
+MojoDeadline TimeTicksToMojoDeadline(base::TimeTicks time_ticks,
+                                     base::TimeTicks now) {
+  // The is_null() check matches that of HandleWatcher.
+  if (time_ticks.is_null())
+    return MOJO_DEADLINE_INDEFINITE;
+  const int64_t delta = (time_ticks - now).InMicroseconds();
+  return delta < 0 ? static_cast<MojoDeadline>(0) :
+                     static_cast<MojoDeadline>(delta);
+}
+
+}  // namespace
 
 // State needed for one iteration of WaitMany. The first handle and flags
 // corresponds to that of the control pipe.
 struct MessagePumpMojo::WaitState {
   std::vector<Handle> handles;
   std::vector<MojoHandleSignals> wait_signals;
 };
 
 struct MessagePumpMojo::RunState {
   RunState() : should_quit(false) {
@@ skipping 17 matching lines @@
 
 // static
 scoped_ptr<base::MessagePump> MessagePumpMojo::Create() {
   return scoped_ptr<MessagePump>(new MessagePumpMojo());
 }
 
 void MessagePumpMojo::AddHandler(MessagePumpMojoHandler* handler,
                                  const Handle& handle,
                                  MojoHandleSignals wait_signals,
                                  base::TimeTicks deadline) {
-  DCHECK(handler);
+  CHECK(handler);
   DCHECK(handle.is_valid());
   // Assume it's an error if someone tries to reregister an existing handle.
-  DCHECK_EQ(0u, handlers_.count(handle));
+  CHECK_EQ(0u, handlers_.count(handle));
   Handler handler_data;
   handler_data.handler = handler;
   handler_data.wait_signals = wait_signals;
   handler_data.deadline = deadline;
   handler_data.id = next_handler_id_++;
   handlers_[handle] = handler_data;
 }
 
 void MessagePumpMojo::RemoveHandler(const Handle& handle) {
   handlers_.erase(handle);
@@ skipping 28 matching lines @@
   if (run_state_)
     SignalControlPipe(*run_state_);
 }
 
 void MessagePumpMojo::ScheduleDelayedWork(
     const base::TimeTicks& delayed_work_time) {
   base::AutoLock auto_lock(run_state_lock_);
   if (!run_state_)
     return;
   run_state_->delayed_work_time = delayed_work_time;
   SignalControlPipe(*run_state_);

[sky, 2014/08/13 17:06:33]

This isn't needed as ScheduleDelayedWork is only invoked on the same thread as
Run is invoked on and when we're not in a wait call.

 }
 
 void MessagePumpMojo::DoRunLoop(RunState* run_state, Delegate* delegate) {
   bool more_work_is_plausible = true;
   for (;;) {
     const bool block = !more_work_is_plausible;
     DoInternalWork(*run_state, block);
 
     // There isn't a good way to know if there are more handles ready, we assume
     // not.
@@ skipping 61 matching lines @@
     if (!i->second.deadline.is_null() && i->second.deadline < now &&
         handlers_.find(i->first) != handlers_.end() &&
         handlers_[i->first].id == i->second.id) {
       i->second.handler->OnHandleError(i->first, MOJO_RESULT_DEADLINE_EXCEEDED);
     }
   }
 }
 
 void MessagePumpMojo::RemoveFirstInvalidHandle(const WaitState& wait_state) {
   // TODO(sky): deal with control pipe going bad.
-  for (size_t i = 1; i < wait_state.handles.size(); ++i) {
+  for (size_t i = 0; i < wait_state.handles.size(); ++i) {
     const MojoResult result =
         Wait(wait_state.handles[i], wait_state.wait_signals[i], 0);
     if (result == MOJO_RESULT_INVALID_ARGUMENT) {
       // We should never have an invalid argument. If we do it indicates
       // RemoveHandler() was not invoked and is likely to cause problems else
       // where in the stack if we ignore it.
       CHECK(false);
     } else if (result == MOJO_RESULT_FAILED_PRECONDITION ||
                result == MOJO_RESULT_CANCELLED) {
+      CHECK_NE(i, 0u);  // Indicates the control pipe went bad.
+
       // Remove the handle first, this way if OnHandleError() tries to remove
       // the handle our iterator isn't invalidated.
-      DCHECK(handlers_.find(wait_state.handles[i]) != handlers_.end());
+      CHECK(handlers_.find(wait_state.handles[i]) != handlers_.end());
       MessagePumpMojoHandler* handler =
           handlers_[wait_state.handles[i]].handler;
       handlers_.erase(wait_state.handles[i]);
       handler->OnHandleError(wait_state.handles[i], result);
       return;
     }
   }
 }
 
 void MessagePumpMojo::SignalControlPipe(const RunState& run_state) {
-  // TODO(sky): deal with error?
-  WriteMessageRaw(run_state.write_handle.get(), NULL, 0, NULL, 0,
-                  MOJO_WRITE_MESSAGE_FLAG_NONE);
+  const MojoResult result =
+      WriteMessageRaw(run_state.write_handle.get(), NULL, 0, NULL, 0,
+                      MOJO_WRITE_MESSAGE_FLAG_NONE);
+  // If we can't write we likely won't wake up the thread and there is a strong
+  // chance we'll deadlock.
+  CHECK_EQ(MOJO_RESULT_OK, result);
 }
 
 MessagePumpMojo::WaitState MessagePumpMojo::GetWaitState(
     const RunState& run_state) const {
   WaitState wait_state;
   wait_state.handles.push_back(run_state.read_handle.get());
   wait_state.wait_signals.push_back(MOJO_HANDLE_SIGNAL_READABLE);
 
   for (HandleToHandler::const_iterator i = handlers_.begin();
        i != handlers_.end(); ++i) {
     wait_state.handles.push_back(i->first);
     wait_state.wait_signals.push_back(i->second.wait_signals);
   }
   return wait_state;
 }
 
 MojoDeadline MessagePumpMojo::GetDeadlineForWait(
     const RunState& run_state) const {
-  base::TimeTicks min_time = run_state.delayed_work_time;
+  const base::TimeTicks now(internal::NowTicks());
+  MojoDeadline deadline = static_cast<MojoDeadline>(0);
+  if (!run_state.delayed_work_time.is_null())
+    deadline = TimeTicksToMojoDeadline(run_state.delayed_work_time, now);
   for (HandleToHandler::const_iterator i = handlers_.begin();
        i != handlers_.end(); ++i) {
-    if (min_time.is_null() && i->second.deadline < min_time)
-      min_time = i->second.deadline;
+    deadline = std::min(
+        TimeTicksToMojoDeadline(i->second.deadline, now), deadline);
   }
-  return min_time.is_null() ? MOJO_DEADLINE_INDEFINITE :
-      std::max(static_cast<MojoDeadline>(0),
-               static_cast<MojoDeadline>(
-                   (min_time - internal::NowTicks()).InMicroseconds()));
+  return deadline;
 }
 
 }  // namespace common
 }  // namespace mojo