Update monet.

mojo/message_pump/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 "mojo/message_pump/message_pump_mojo.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/debug/alias.h"
-#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/threading/thread_local.h"
 #include "base/time/time.h"
-#include "mojo/common/message_pump_mojo_handler.h"
-#include "mojo/common/time_helper.h"
+#include "mojo/message_pump/message_pump_mojo_handler.h"
+#include "mojo/message_pump/time_helper.h"
+#include "mojo/public/cpp/system/message_pipe.h"
+#include "mojo/public/cpp/system/wait.h"
 
 namespace mojo {
 namespace common {
 namespace {
 
-base::LazyInstance<base::ThreadLocalPointer<MessagePumpMojo> >::Leaky
-    g_tls_current_pump = LAZY_INSTANCE_INITIALIZER;
+base::ThreadLocalPointer<MessagePumpMojo>* CurrentPump() {
+  static auto* tls = new base::ThreadLocalPointer<MessagePumpMojo>;
+  return tls;
+}
 
 MojoDeadline TimeTicksToMojoDeadline(base::TimeTicks time_ticks,
                                      base::TimeTicks now) {
   // The is_null() check matches that of HandleWatcher as well as how
   // |delayed_work_time| is used.
   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) {
-    CreateMessagePipe(NULL, &read_handle, &write_handle);
+    CreateMessagePipe(nullptr, &read_handle, &write_handle);
   }
 
   base::TimeTicks delayed_work_time;
 
   // Used to wake up WaitForWork().
   ScopedMessagePipeHandle read_handle;
   ScopedMessagePipeHandle write_handle;
 
+  // Cached structures to avoid the heap allocation cost of std::vector<>.
+  scoped_ptr<WaitState> wait_state;
+  scoped_ptr<HandleToHandlerList> cloned_handlers;
+
   bool should_quit;
 };
 
-MessagePumpMojo::MessagePumpMojo() : run_state_(NULL), next_handler_id_(0) {
+MessagePumpMojo::MessagePumpMojo() : run_state_(nullptr), next_handler_id_(0) {
   DCHECK(!current())
       << "There is already a MessagePumpMojo instance on this thread.";
-  g_tls_current_pump.Pointer()->Set(this);
+  CurrentPump()->Set(this);
 }
 
 MessagePumpMojo::~MessagePumpMojo() {
   DCHECK_EQ(this, current());
-  g_tls_current_pump.Pointer()->Set(NULL);
+  CurrentPump()->Set(nullptr);
 }
 
 // static
 scoped_ptr<base::MessagePump> MessagePumpMojo::Create() {
   return scoped_ptr<MessagePump>(new MessagePumpMojo());
 }
 
 // static
 MessagePumpMojo* MessagePumpMojo::current() {
-  return g_tls_current_pump.Pointer()->Get();
+  return CurrentPump()->Get();
 }
 
 void MessagePumpMojo::AddHandler(MessagePumpMojoHandler* handler,
                                  const Handle& handle,
                                  MojoHandleSignals wait_signals,
                                  base::TimeTicks deadline) {
   CHECK(handler);
   DCHECK(handle.is_valid());
   // Assume it's an error if someone tries to reregister an existing handle.
   CHECK_EQ(0u, handlers_.count(handle));
@@ skipping 15 matching lines @@
 
 void MessagePumpMojo::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
 void MessagePumpMojo::Run(Delegate* delegate) {
   RunState run_state;
   // TODO: better deal with error handling.
   CHECK(run_state.read_handle.is_valid());
   CHECK(run_state.write_handle.is_valid());
-  RunState* old_state = NULL;
+  RunState* old_state = nullptr;
   {
     base::AutoLock auto_lock(run_state_lock_);
     old_state = run_state_;
     run_state_ = &run_state;
   }
   DoRunLoop(&run_state, delegate);
   {
     base::AutoLock auto_lock(run_state_lock_);
     run_state_ = old_state;
   }
@@ skipping 41 matching lines @@
       continue;
 
     more_work_is_plausible = delegate->DoIdleWork();
     if (run_state->should_quit)
       break;
   }
 }
 
 bool MessagePumpMojo::DoInternalWork(const RunState& run_state, bool block) {
   const MojoDeadline deadline = block ? GetDeadlineForWait(run_state) : 0;
-  const WaitState wait_state = GetWaitState(run_state);
+  if (!run_state_->wait_state)
+    run_state_->wait_state.reset(new WaitState);
+  GetWaitState(run_state, run_state_->wait_state.get());
 
   const WaitManyResult wait_many_result =
-      WaitMany(wait_state.handles, wait_state.wait_signals, deadline, nullptr);
+      WaitMany(run_state_->wait_state->handles,
+               run_state_->wait_state->wait_signals, deadline, nullptr);
   const MojoResult result = wait_many_result.result;
   bool did_work = true;
   if (result == MOJO_RESULT_OK) {
     if (wait_many_result.index == 0) {
       // Control pipe was written to.
-      ReadMessageRaw(run_state.read_handle.get(), NULL, NULL, NULL, NULL,
-                     MOJO_READ_MESSAGE_FLAG_MAY_DISCARD);
+      ReadMessageRaw(run_state.read_handle.get(), nullptr, nullptr, nullptr,
+                     nullptr, MOJO_READ_MESSAGE_FLAG_MAY_DISCARD);
     } else {
-      DCHECK(handlers_.find(wait_state.handles[wait_many_result.index]) !=
+      DCHECK(handlers_.find(
+                 run_state_->wait_state->handles[wait_many_result.index]) !=
              handlers_.end());
       WillSignalHandler();
-      handlers_[wait_state.handles[wait_many_result.index]]
-          .handler->OnHandleReady(wait_state.handles[wait_many_result.index]);
+      handlers_[run_state_->wait_state->handles[wait_many_result.index]]
+          .handler->OnHandleReady(
+              run_state_->wait_state->handles[wait_many_result.index]);
       DidSignalHandler();
     }
   } else {
     switch (result) {
-      case MOJO_RESULT_CANCELLED:
       case MOJO_RESULT_FAILED_PRECONDITION:
-        RemoveInvalidHandle(wait_state, result, wait_many_result.index);
+        RemoveInvalidHandle(*run_state_->wait_state, result,
+                            wait_many_result.index);
         break;
       case MOJO_RESULT_DEADLINE_EXCEEDED:
         did_work = false;
         break;
+      case MOJO_RESULT_INVALID_ARGUMENT:
+      case MOJO_RESULT_CANCELLED:
+      case MOJO_RESULT_BUSY:
+        // These results indicate a bug in "our" code (e.g., race conditions).
+        // Fall through.
       default:
         base::debug::Alias(&result);
         // Unexpected result is likely fatal, crash so we can determine cause.
         CHECK(false);
     }
   }
+  // To keep memory usage under control, delete the WaitState object at the end
+  // if it's vectors are too big by a factor of 2. Pre-C++11 doesn't have a way
+  // to shrink vectors, so just get rid of them and re-create on the next round.
+  if (run_state_->wait_state->handles.capacity() >
+      2 * run_state_->wait_state->handles.size()) {
+    // NOTE: |handles| and |wait_signals| are always in sync, so it's reasonable
+    // to only check one of those.
+    run_state_->wait_state.reset();
+  }
 
   // Notify and remove any handlers whose time has expired. Make a copy in case
   // someone tries to add/remove new handlers from notification.
-  const HandleToHandler cloned_handlers(handlers_);
+  if (!run_state_->cloned_handlers) {
+    run_state_->cloned_handlers.reset(new HandleToHandlerList);
+  } else {
+    run_state_->cloned_handlers->clear();
+  }
+  run_state_->cloned_handlers->reserve(handlers_.size());
+  for (const auto& handler : handlers_) {
+    run_state_->cloned_handlers->push_back(handler);
+  }
   const base::TimeTicks now(internal::NowTicks());
-  for (HandleToHandler::const_iterator i = cloned_handlers.begin();
-       i != cloned_handlers.end(); ++i) {
+  for (HandleToHandlerList::const_iterator i =
+           run_state_->cloned_handlers->begin();
+       i != run_state_->cloned_handlers->end(); ++i) {
     // Since we're iterating over a clone of the handlers, verify the handler is
     // still valid before notifying.
     if (!i->second.deadline.is_null() && i->second.deadline < now &&
         handlers_.find(i->first) != handlers_.end() &&
         handlers_[i->first].id == i->second.id) {
       WillSignalHandler();
       i->second.handler->OnHandleError(i->first, MOJO_RESULT_DEADLINE_EXCEEDED);
       DidSignalHandler();
       handlers_.erase(i->first);
       did_work = true;
     }
   }
+  if (run_state_->cloned_handlers->capacity() >
+      2 * run_state_->cloned_handlers->size()) {
+    run_state_->cloned_handlers.reset();
+  }
   return did_work;
 }
 
 void MessagePumpMojo::RemoveInvalidHandle(const WaitState& wait_state,
                                           MojoResult result,
                                           uint32_t index) {
   // TODO(sky): deal with control pipe going bad.
   CHECK(result == MOJO_RESULT_FAILED_PRECONDITION ||
         result == MOJO_RESULT_CANCELLED);
   CHECK_NE(index, 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.
   CHECK(handlers_.find(wait_state.handles[index]) != handlers_.end());
   MessagePumpMojoHandler* handler =
       handlers_[wait_state.handles[index]].handler;
   handlers_.erase(wait_state.handles[index]);
   WillSignalHandler();
   handler->OnHandleError(wait_state.handles[index], result);
   DidSignalHandler();
 }
 
 void MessagePumpMojo::SignalControlPipe(const RunState& run_state) {
   const MojoResult result =
-      WriteMessageRaw(run_state.write_handle.get(), NULL, 0, NULL, 0,
+      WriteMessageRaw(run_state.write_handle.get(), nullptr, 0, nullptr, 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);
+void MessagePumpMojo::GetWaitState(
+    const RunState& run_state,
+    MessagePumpMojo::WaitState* wait_state) const {
+  const size_t num_handles = handlers_.size() + 1;
+  wait_state->handles.clear();
+  wait_state->handles.reserve(num_handles);
+  wait_state->wait_signals.clear();
+  wait_state->wait_signals.reserve(num_handles);
+  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);
+    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 {
   const base::TimeTicks now(internal::NowTicks());
   MojoDeadline deadline = TimeTicksToMojoDeadline(run_state.delayed_work_time,
                                                   now);
   for (HandleToHandler::const_iterator i = handlers_.begin();
        i != handlers_.end(); ++i) {
     deadline = std::min(
         TimeTicksToMojoDeadline(i->second.deadline, now), deadline);
   }
   return deadline;
 }
 
 void MessagePumpMojo::WillSignalHandler() {
   FOR_EACH_OBSERVER(Observer, observers_, WillSignalHandler());
 }
 
 void MessagePumpMojo::DidSignalHandler() {
   FOR_EACH_OBSERVER(Observer, observers_, DidSignalHandler());
 }
 
 }  // namespace common
 }  // namespace mojo