Use chrome/base synchronization primitives and threads instead of...

chrome/browser/sync/engine/syncer_thread.cc

Index: chrome/browser/sync/engine/syncer_thread.cc
===================================================================
--- chrome/browser/sync/engine/syncer_thread.cc	(revision 27084)
+++ chrome/browser/sync/engine/syncer_thread.cc	(working copy)
@@ -1,7 +1,6 @@
 // Copyright (c) 2009 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 "chrome/browser/sync/engine/syncer_thread.h"
 
 #include "build/build_config.h"
@@ -16,21 +15,24 @@
 #include <map>
 #include <queue>
 
+#include "base/command_line.h"
 #include "chrome/browser/sync/engine/auth_watcher.h"
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 #include "chrome/browser/sync/engine/net/server_connection_manager.h"
 #include "chrome/browser/sync/engine/syncer.h"
+#include "chrome/browser/sync/engine/syncer_thread_pthreads.h"
+#include "chrome/browser/sync/engine/syncer_thread_timed_stop.h"
 #include "chrome/browser/sync/notifier/listener/talk_mediator.h"
 #include "chrome/browser/sync/notifier/listener/talk_mediator_impl.h"
 #include "chrome/browser/sync/syncable/directory_manager.h"
+#include "chrome/common/chrome_switches.h"
 
 using std::priority_queue;
 using std::min;
+using base::Time;
+using base::TimeDelta;
+using base::TimeTicks;
 
-static inline bool operator < (const timespec& a, const timespec& b) {
-  return a.tv_sec == b.tv_sec ? a.tv_nsec < b.tv_nsec : a.tv_sec < b.tv_sec;
-}
-
 namespace {
 
 // Returns the amount of time since the user last interacted with the computer,
@@ -108,17 +110,56 @@
 
 namespace browser_sync {
 
+SyncerThread* SyncerThreadFactory::Create(
+    ClientCommandChannel* command_channel,
+    syncable::DirectoryManager* mgr,
+    ServerConnectionManager* connection_manager, AllStatus* all_status,
+    ModelSafeWorker* model_safe_worker) {
+  const CommandLine* cmd = CommandLine::ForCurrentProcess();
+  if (cmd->HasSwitch(switches::kSyncerThreadTimedStop)) {
+    return new SyncerThreadTimedStop(command_channel, mgr, connection_manager,
+        all_status, model_safe_worker);
+  } else if (cmd->HasSwitch(switches::kSyncerThreadPthreads)) {
+    return new SyncerThreadPthreads(command_channel, mgr, connection_manager,
+        all_status, model_safe_worker);
+  } else {
+    // The default SyncerThread implementation, which does not time-out when
+    // Stop is called.
+    return new SyncerThread(command_channel, mgr, connection_manager,
+        all_status, model_safe_worker);
+  }
+}
+
 bool SyncerThread::NudgeSyncer(int milliseconds_from_now, NudgeSource source) {
-  MutexLock lock(&mutex_);
-  if (syncer_ == NULL) {
+  AutoLock lock(lock_);
+  if (vault_.syncer_ == NULL) {
     return false;
   }
   NudgeSyncImpl(milliseconds_from_now, source);
   return true;
 }
 
-void* RunSyncerThread(void* syncer_thread) {
-  return (reinterpret_cast<SyncerThread*>(syncer_thread))->ThreadMain();
+SyncerThread::SyncerThread()
+    : thread_main_started_(false, false),
+      thread_("SyncEngine_SyncerThread"),
+      vault_field_changed_(&lock_),
+      p2p_authenticated_(false),
+      p2p_subscribed_(false),
+      client_command_hookup_(NULL),
+      conn_mgr_hookup_(NULL),
+      allstatus_(NULL),
+      dirman_(NULL),
+      scm_(NULL),
+      syncer_short_poll_interval_seconds_(kDefaultShortPollIntervalSeconds),
+      syncer_long_poll_interval_seconds_(kDefaultLongPollIntervalSeconds),
+      syncer_polling_interval_(kDefaultShortPollIntervalSeconds),
+      syncer_max_interval_(kDefaultMaxPollIntervalMs),
+      talk_mediator_hookup_(NULL),
+      command_channel_(NULL),
+      directory_manager_hookup_(NULL),
+      syncer_events_(NULL),
+      model_safe_worker_(NULL),
+      disable_idle_detection_(false) {
 }
 
 SyncerThread::SyncerThread(
@@ -127,18 +168,26 @@
     ServerConnectionManager* connection_manager,
     AllStatus* all_status,
     ModelSafeWorker* model_safe_worker)
-    : dirman_(mgr), scm_(connection_manager),
-      syncer_(NULL), syncer_events_(NULL), thread_running_(false),
+    : thread_main_started_(false, false),
+      thread_("SyncEngine_SyncerThread"),
+      vault_field_changed_(&lock_),
+      p2p_authenticated_(false),
+      p2p_subscribed_(false),
+      client_command_hookup_(NULL),
+      conn_mgr_hookup_(NULL),
+      allstatus_(all_status),
+      dirman_(mgr),
+      scm_(connection_manager),
       syncer_short_poll_interval_seconds_(kDefaultShortPollIntervalSeconds),
       syncer_long_poll_interval_seconds_(kDefaultLongPollIntervalSeconds),
       syncer_polling_interval_(kDefaultShortPollIntervalSeconds),
       syncer_max_interval_(kDefaultMaxPollIntervalMs),
-      stop_syncer_thread_(false), connected_(false), conn_mgr_hookup_(NULL),
-      p2p_authenticated_(false), p2p_subscribed_(false),
-      allstatus_(all_status), talk_mediator_hookup_(NULL),
-      command_channel_(command_channel), directory_manager_hookup_(NULL),
+      talk_mediator_hookup_(NULL),
+      command_channel_(command_channel),
+      directory_manager_hookup_(NULL),
+      syncer_events_(NULL),
       model_safe_worker_(model_safe_worker),
-      client_command_hookup_(NULL), disable_idle_detection_(false) {
+      disable_idle_detection_(false) {
 
   SyncerEvent shutdown = { SyncerEvent::SHUTDOWN_USE_WITH_CARE };
   syncer_event_channel_.reset(new SyncerEventChannel(shutdown));
@@ -163,55 +212,76 @@
   syncer_event_channel_.reset();
   directory_manager_hookup_.reset();
   syncer_events_.reset();
-  delete syncer_;
+  delete vault_.syncer_;
   talk_mediator_hookup_.reset();
-  CHECK(!thread_running_);
+  CHECK(!thread_.IsRunning());
 }
 
 // Creates and starts a syncer thread.
 // Returns true if it creates a thread or if there's currently a thread running
 // and false otherwise.
 bool SyncerThread::Start() {
-  MutexLock lock(&mutex_);
-  if (thread_running_) {
-    return true;
+  {
+    AutoLock lock(lock_);
+    if (thread_.IsRunning()) {
+      return true;
+    }
+
+    if (!thread_.Start()) {
+      return false;
+    }
   }
-  thread_running_ =
-    (0 == pthread_create(&thread_, NULL, RunSyncerThread, this));
-  if (thread_running_) {
-    pthread_detach(thread_);
-  }
-  return thread_running_;
+
+  thread_.message_loop()->PostTask(FROM_HERE, NewRunnableMethod(this,
+      &SyncerThread::ThreadMain));
+
+  // Wait for notification that our task makes it safely onto the message
+  // loop before returning, so the caller can't call Stop before we're
+  // actually up and running.  This is for consistency with the old pthread
+  // impl because pthread_create would do this in one step.
+  thread_main_started_.Wait();
+  LOG(INFO) << "SyncerThread started.";
+  return true;
 }
 
 // Stop processing. A max wait of at least 2*server RTT time is recommended.
 // Returns true if we stopped, false otherwise.
 bool SyncerThread::Stop(int max_wait) {
-  MutexLock lock(&mutex_);
-  if (!thread_running_)
-    return true;
-  stop_syncer_thread_ = true;
-  if (NULL != syncer_) {
-    // Try to early exit the syncer.
-    syncer_->RequestEarlyExit();
+  {
+    AutoLock lock(lock_);
+    // If the thread has been started, then we either already have or are about
+    // to enter ThreadMainLoop so we have to proceed with shutdown and wait for
+    // it to finish.  If the thread has not been started --and we now own the
+    // lock-- then we can early out because the caller has not called Start().
+    if (!thread_.IsRunning())
+      return true;
+
+    LOG(INFO) << "SyncerThread::Stop - setting ThreadMain exit condition to "
+              << "true (vault_.stop_syncer_thread_)";
+    // Exit the ThreadMainLoop once the syncer finishes (we tell it to exit
+    // below).
+    vault_.stop_syncer_thread_ = true;
+    if (NULL != vault_.syncer_) {
+      // Try to early exit the syncer itself, which could be looping inside
+      // SyncShare.
+      vault_.syncer_->RequestEarlyExit();
+    }
+
+    // stop_syncer_thread_ is now true and the Syncer has been told to exit.
+    // We want to wake up all waiters so they can re-examine state. We signal,
+    // causing all waiters to try to re-acquire the lock, and then we release
+    // the lock, and join on our internal thread which should soon run off the
+    // end of ThreadMain.
+    vault_field_changed_.Broadcast();
   }
-  pthread_cond_broadcast(&changed_.condvar_);
-  timespec deadline = { time(NULL) + (max_wait / 1000), 0 };
-  do {
-    const int wait_result = max_wait < 0 ?
-      pthread_cond_wait(&changed_.condvar_, &mutex_.mutex_) :
-      pthread_cond_timedwait(&changed_.condvar_, &mutex_.mutex_,
-                             &deadline);
-    if (ETIMEDOUT == wait_result) {
-      LOG(ERROR) << "SyncerThread::Stop timed out. Problems likely.";
-      return false;
-    }
-  } while (thread_running_);
+
+  // This will join, and finish when ThreadMain terminates.
+  thread_.Stop();
   return true;
 }
 
 void SyncerThread::WatchClientCommands(ClientCommandChannel* channel) {
-  PThreadScopedLock<PThreadMutex> lock(&mutex_);
+  AutoLock lock(lock_);
   client_command_hookup_.reset(NewEventListenerHookup(channel, this,
       &SyncerThread::HandleClientCommand));
 }
@@ -232,67 +302,89 @@
 }
 
 void SyncerThread::ThreadMainLoop() {
+  // This is called with lock_ acquired.
+  lock_.AssertAcquired();
+  LOG(INFO) << "In thread main loop.";
+
   // Use the short poll value by default.
-  int poll_seconds = syncer_short_poll_interval_seconds_;
+  TimeDelta poll_seconds =
+      TimeDelta::FromSeconds(syncer_short_poll_interval_seconds_);
   int user_idle_milliseconds = 0;
-  timespec last_sync_time = { 0 };
+  TimeTicks last_sync_time;
   bool initial_sync_for_thread = true;
   bool continue_sync_cycle = false;
 
-  while (!stop_syncer_thread_) {
-    if (!connected_) {
+  while (!vault_.stop_syncer_thread_) {
+    // The Wait()s in these conditionals using |vault_| are not TimedWait()s (as
+    // below) because we cannot poll until these conditions are met, so we wait
+    // indefinitely.
+    if (!vault_.connected_) {
       LOG(INFO) << "Syncer thread waiting for connection.";
-      while (!connected_ && !stop_syncer_thread_)
-        pthread_cond_wait(&changed_.condvar_, &mutex_.mutex_);
-      LOG_IF(INFO, connected_) << "Syncer thread found connection.";
+      while (!vault_.connected_ && !vault_.stop_syncer_thread_)
+        vault_field_changed_.Wait();
+      LOG_IF(INFO, vault_.connected_) << "Syncer thread found connection.";
       continue;
     }
 
-    if (syncer_ == NULL) {
+    if (vault_.syncer_ == NULL) {
       LOG(INFO) << "Syncer thread waiting for database initialization.";
-      while (syncer_ == NULL && !stop_syncer_thread_)
-        pthread_cond_wait(&changed_.condvar_, &mutex_.mutex_);
-      LOG_IF(INFO, !(syncer_ == NULL)) << "Syncer was found after DB started.";
+      while (vault_.syncer_ == NULL && !vault_.stop_syncer_thread_)
+        vault_field_changed_.Wait();
+      LOG_IF(INFO, !(vault_.syncer_ == NULL))
+          << "Syncer was found after DB started.";
       continue;
     }
 
-    timespec const next_poll = { last_sync_time.tv_sec + poll_seconds,
-                                 last_sync_time.tv_nsec };
-    const timespec wake_time =
-      !nudge_queue_.empty() && nudge_queue_.top().first < next_poll ?
-      nudge_queue_.top().first : next_poll;
-    LOG(INFO) << "wake time is " << wake_time.tv_sec;
-    LOG(INFO) << "next poll is " << next_poll.tv_sec;
+    const TimeTicks next_poll = last_sync_time + poll_seconds;
+    const TimeTicks end_wait =
+        !vault_.nudge_queue_.empty() &&
+        vault_.nudge_queue_.top().first < next_poll ?
+        vault_.nudge_queue_.top().first : next_poll;
+    LOG(INFO) << "end_wait is " << end_wait.ToInternalValue();
+    LOG(INFO) << "next_poll is " << next_poll.ToInternalValue();
 
-    const int error = pthread_cond_timedwait(&changed_.condvar_, &mutex_.mutex_,
-                                             &wake_time);
-    if (ETIMEDOUT != error) {
-      continue;  // Check all the conditions again.
+    // We block until the CV is signaled (e.g a control field changed, loss of
+    // network connection, nudge, spurious, etc), or the poll interval elapses.
+    TimeDelta sleep_time = end_wait - TimeTicks::Now();
+    if (sleep_time > TimeDelta::FromSeconds(0)) {
+      vault_field_changed_.TimedWait(sleep_time);
+
+      if (TimeTicks::Now() < end_wait) {
+        // Didn't timeout. Could be a spurious signal, or a signal corresponding
+        // to an actual change in one of our control fields.  By continuing here
+        // we perform the typical "always recheck conditions when signaled",
+        // (typically handled by a while(condition_not_met) cv.wait() construct)
+        // because we jump to the top of the loop.  The main difference is we
+        // recalculate the wait interval, but last_sync_time won't have changed.
+        // So if we were signaled by a nudge (for ex.) we'll grab the new nudge
+        // off the queue and wait for that delta.  If it was a spurious signal,
+        // we'll keep waiting for the same moment in time as we just were.
+        continue;
+       }
     }
 
-    const timespec now = GetPThreadAbsoluteTime(0);
-
     // Handle a nudge, caused by either a notification or a local bookmark
     // event.  This will also update the source of the following SyncMain call.
-    UpdateNudgeSource(now, &continue_sync_cycle, &initial_sync_for_thread);
+    UpdateNudgeSource(&continue_sync_cycle, &initial_sync_for_thread);
 
-    LOG(INFO) << "Calling Sync Main at time " << now.tv_sec;
-    SyncMain(syncer_);
-    last_sync_time = now;
+    LOG(INFO) << "Calling Sync Main at time " << Time::Now().ToInternalValue();
+    SyncMain(vault_.syncer_);
+    last_sync_time = TimeTicks::Now();
 
     LOG(INFO) << "Updating the next polling time after SyncMain";
-    poll_seconds = CalculatePollingWaitTime(allstatus_->status(),
-                                            poll_seconds,
-                                            &user_idle_milliseconds,
-                                            &continue_sync_cycle);
+    poll_seconds = TimeDelta::FromSeconds(CalculatePollingWaitTime(
+        allstatus_->status(), static_cast<int>(poll_seconds.InSeconds()),
+        &user_idle_milliseconds, &continue_sync_cycle));
   }
+
 }
 
 // We check how long the user's been idle and sync less often if the machine is
 // not in use. The aim is to reduce server load.
+// TODO(timsteele): Should use Time(Delta).
 int SyncerThread::CalculatePollingWaitTime(
     const AllStatus::Status& status,
-    int last_poll_wait,  // in s
+    int last_poll_wait,  // Time in seconds.
     int* user_idle_milliseconds,
     bool* continue_sync_cycle) {
   bool is_continuing_sync_cyle = *continue_sync_cycle;
@@ -343,30 +435,25 @@
   return actual_next_wait;
 }
 
-void* SyncerThread::ThreadMain() {
-  NameCurrentThreadForDebugging("SyncEngine_SyncerThread");
-  mutex_.Lock();
+void SyncerThread::ThreadMain() {
+  AutoLock lock(lock_);
+  // Signal Start() to let it know we've made it safely onto the message loop,
+  // and unblock it's caller.
+  thread_main_started_.Signal();
   ThreadMainLoop();
-  thread_running_ = false;
-  pthread_cond_broadcast(&changed_.condvar_);
-  mutex_.Unlock();
-  LOG(INFO) << "Syncer thread exiting.";
-  return 0;
+  LOG(INFO) << "Syncer thread ThreadMain is done.";
 }
 
 void SyncerThread::SyncMain(Syncer* syncer) {
   CHECK(syncer);
-  mutex_.Unlock();
+  AutoUnlock unlock(lock_);
   while (syncer->SyncShare()) {
     LOG(INFO) << "Looping in sync share";
   }
   LOG(INFO) << "Done looping in sync share";
-
-  mutex_.Lock();
 }
 
-void SyncerThread::UpdateNudgeSource(const timespec& now,
-                                     bool* continue_sync_cycle,
+void SyncerThread::UpdateNudgeSource(bool* continue_sync_cycle,
                                      bool* initial_sync) {
   bool nudged = false;
   NudgeSource nudge_source = kUnknown;
@@ -376,13 +463,14 @@
   }
   // Update the nudge source if a new nudge has come through during the
   // previous sync cycle.
-  while (!nudge_queue_.empty() && !(now < nudge_queue_.top().first)) {
+  while (!vault_.nudge_queue_.empty() &&
+         TimeTicks::Now() >= vault_.nudge_queue_.top().first) {
     if (!nudged) {
-      nudge_source = nudge_queue_.top().second;
+      nudge_source = vault_.nudge_queue_.top().second;
       *continue_sync_cycle = false;  //  Reset the continuation token on nudge.
       nudged = true;
     }
-    nudge_queue_.pop();
+    vault_.nudge_queue_.pop();
   }
   SetUpdatesSource(nudged, nudge_source, initial_sync);
 }
@@ -413,11 +501,11 @@
         break;
     }
   }
-  syncer_->set_updates_source(updates_source);
+  vault_.syncer_->set_updates_source(updates_source);
 }
 
 void SyncerThread::HandleSyncerEvent(const SyncerEvent& event) {
-  MutexLock lock(&mutex_);
+  AutoLock lock(lock_);
   channel()->NotifyListeners(event);
   if (SyncerEvent::REQUEST_SYNC_NUDGE != event.what_happened) {
     return;
@@ -429,33 +517,33 @@
     const syncable::DirectoryManagerEvent& event) {
   LOG(INFO) << "Handling a directory manager event";
   if (syncable::DirectoryManagerEvent::OPENED == event.what_happened) {
-    MutexLock lock(&mutex_);
+    AutoLock lock(lock_);
     LOG(INFO) << "Syncer starting up for: " << event.dirname;
     // The underlying database structure is ready, and we should create
     // the syncer.
-    CHECK(syncer_ == NULL);
-    syncer_ =
+    CHECK(vault_.syncer_ == NULL);
+    vault_.syncer_ =
         new Syncer(dirman_, event.dirname, scm_, model_safe_worker_.get());
 
-    syncer_->set_command_channel(command_channel_);
+    vault_.syncer_->set_command_channel(command_channel_);
     syncer_events_.reset(NewEventListenerHookup(
-        syncer_->channel(), this, &SyncerThread::HandleSyncerEvent));
-    pthread_cond_broadcast(&changed_.condvar_);
+        vault_.syncer_->channel(), this, &SyncerThread::HandleSyncerEvent));
+    vault_field_changed_.Broadcast();
   }
 }
 
 static inline void CheckConnected(bool* connected,
                                   HttpResponse::ServerConnectionCode code,
-                                  pthread_cond_t* condvar) {
+                                  ConditionVariable* condvar) {
   if (*connected) {
     if (HttpResponse::CONNECTION_UNAVAILABLE == code) {
       *connected = false;
-      pthread_cond_broadcast(condvar);
+      condvar->Broadcast();
     }
   } else {
     if (HttpResponse::SERVER_CONNECTION_OK == code) {
       *connected = true;
-      pthread_cond_broadcast(condvar);
+      condvar->Broadcast();
     }
   }
 }
@@ -463,16 +551,16 @@
 void SyncerThread::WatchConnectionManager(ServerConnectionManager* conn_mgr) {
   conn_mgr_hookup_.reset(NewEventListenerHookup(conn_mgr->channel(), this,
                          &SyncerThread::HandleServerConnectionEvent));
-  CheckConnected(&connected_, conn_mgr->server_status(),
-                 &changed_.condvar_);
+  CheckConnected(&vault_.connected_, conn_mgr->server_status(),
+                 &vault_field_changed_);
 }
 
 void SyncerThread::HandleServerConnectionEvent(
     const ServerConnectionEvent& event) {
   if (ServerConnectionEvent::STATUS_CHANGED == event.what_happened) {
-    MutexLock lock(&mutex_);
-    CheckConnected(&connected_, event.connection_code,
-                   &changed_.condvar_);
+    AutoLock lock(lock_);
+    CheckConnected(&vault_.connected_, event.connection_code,
+                   &vault_field_changed_);
   }
 }
 
@@ -504,10 +592,11 @@
 // Called with mutex_ already locked.
 void SyncerThread::NudgeSyncImpl(int milliseconds_from_now,
                                  NudgeSource source) {
-  const timespec nudge_time = GetPThreadAbsoluteTime(milliseconds_from_now);
+  const TimeTicks nudge_time = TimeTicks::Now() +
+      TimeDelta::FromMilliseconds(milliseconds_from_now);
   NudgeObject nudge_object(nudge_time, source);
-  nudge_queue_.push(nudge_object);
-  pthread_cond_broadcast(&changed_.condvar_);
+  vault_.nudge_queue_.push(nudge_object);
+  vault_field_changed_.Broadcast();
 }
 
 void SyncerThread::WatchTalkMediator(TalkMediator* mediator) {
@@ -519,7 +608,7 @@
 }
 
 void SyncerThread::HandleTalkMediatorEvent(const TalkMediatorEvent& event) {
-  MutexLock lock(&mutex_);
+  AutoLock lock(lock_);
   switch (event.what_happened) {
     case TalkMediatorEvent::LOGIN_SUCCEEDED:
       LOG(INFO) << "P2P: Login succeeded.";
@@ -532,7 +621,7 @@
     case TalkMediatorEvent::SUBSCRIPTIONS_ON:
       LOG(INFO) << "P2P: Subscriptions successfully enabled.";
       p2p_subscribed_ = true;
-      if (NULL != syncer_) {
+      if (NULL != vault_.syncer_) {
         LOG(INFO) << "Subscriptions on.  Nudging syncer for initial push.";
         NudgeSyncImpl(0, kLocal);
       }
@@ -543,7 +632,7 @@
       break;
     case TalkMediatorEvent::NOTIFICATION_RECEIVED:
       LOG(INFO) << "P2P: Updates on server, pushing syncer";
-      if (NULL != syncer_) {
+      if (NULL != vault_.syncer_) {
         NudgeSyncImpl(0, kNotification);
       }
       break;
@@ -551,8 +640,9 @@
       break;
   }
 
-  if (NULL != syncer_) {
-    syncer_->set_notifications_enabled(p2p_authenticated_ && p2p_subscribed_);
+  if (NULL != vault_.syncer_) {
+    vault_.syncer_->set_notifications_enabled(
+        p2p_authenticated_ && p2p_subscribed_);
   }
 }