Initial commit of sync engine code to browser/sync.

The code is not built on any platform yet.  That will arrive
as a subsequent checkin.

This is an implementation of the interface exposed earlier
through syncapi.h.  It is the client side of a sync
protocol that lets users sync their browser data
(currently, just bookmarks) with their Google Account.

Table of contents:

browser/sync/
  protocol - The protocol definition, and
             other definitions necessary to connect to
             the service.
  syncable/ - defines a data model for syncable objects,
              and provides a sqlite-based backing store
              for this model.
  engine/ - includes the core sync logic, including commiting
            changes to the server, downloading changes from
            the server, resolving conflicts, other parts of
            the sync algorithm.
  engine/net - parts of the sync engine focused on the
               business of talking to the server.  Some of
               this is binds a generic "server connection"
               interface to a concrete implementation
               provided by Chromium.
  notifier - the part of the syncer focused on the business
             of sending and receiving xmpp notifications.
             Notifications are used instead of polling to
             achieve very low latency change propagation.
  util - not necessarily sync specific utility code.  Much
         of this is scaffolding which should either be
         replaced by, or merged with, the utility code
         in base/.

BUG=none
TEST=this code includes its own suite of unit tests.

Review URL: http://codereview.chromium.org/194065

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@25850 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 558 insertions, 0 deletions

diff --git a/chrome/browser/sync/engine/syncer_thread.cc b/chrome/browser/sync/engine/syncer_thread.cc
new file mode 100644
index 0000000..e0832a7
--- /dev/null
+++ b/chrome/browser/sync/engine/syncer_thread.cc
@@ -0,0 +1,558 @@
+// 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"
+
+#ifdef OS_MACOSX
+#include <CoreFoundation/CFNumber.h>
+#include <IOKit/IOTypes.h>
+#include <IOKit/IOKitLib.h>
+#endif
+
+#include <algorithm>
+#include <map>
+#include <queue>
+
+#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/notifier/listener/talk_mediator.h"
+#include "chrome/browser/sync/notifier/listener/talk_mediator_impl.h"
+#include "chrome/browser/sync/syncable/directory_manager.h"
+
+using std::priority_queue;
+using std::min;
+
+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, in milliseconds
+int UserIdleTime() {
+#ifdef OS_WINDOWS
+  LASTINPUTINFO last_input_info;
+  last_input_info.cbSize = sizeof(LASTINPUTINFO);
+
+  // get time in windows ticks since system start of last activity
+  BOOL b = ::GetLastInputInfo(&last_input_info);
+  if (b == TRUE)
+    return ::GetTickCount() - last_input_info.dwTime;
+#elif defined(OS_MACOSX)
+  // It would be great to do something like:
+  //
+  // return 1000 *
+  //     CGEventSourceSecondsSinceLastEventType(
+  //         kCGEventSourceStateCombinedSessionState,
+  //         kCGAnyInputEventType);
+  //
+  // Unfortunately, CGEvent* lives in ApplicationServices, and we're a daemon
+  // and can't link that high up the food chain. Thus this mucking in IOKit.
+
+  io_service_t hid_service =
+      IOServiceGetMatchingService(kIOMasterPortDefault,
+                                  IOServiceMatching("IOHIDSystem"));
+  if (!hid_service) {
+    LOG(WARNING) << "Could not obtain IOHIDSystem";
+    return 0;
+  }
+
+  CFTypeRef object = IORegistryEntryCreateCFProperty(hid_service,
+                                                     CFSTR("HIDIdleTime"),
+                                                     kCFAllocatorDefault,
+                                                     0);
+  if (!object) {
+    LOG(WARNING) << "Could not get IOHIDSystem's HIDIdleTime property";
+    IOObjectRelease(hid_service);
+    return 0;
+  }
+
+  int64 idle_time;  // in nanoseconds
+  Boolean success;
+  if (CFGetTypeID(object) == CFNumberGetTypeID()) {
+    success = CFNumberGetValue((CFNumberRef)object,
+                               kCFNumberSInt64Type,
+                               &idle_time);
+  } else {
+    LOG(WARNING) << "IOHIDSystem's HIDIdleTime property isn't a number!";
+  }
+
+  CFRelease(object);
+  IOObjectRelease(hid_service);
+
+  if (!success) {
+    LOG(WARNING) << "Could not get IOHIDSystem's HIDIdleTime property's value";
+    return 0;
+  } else {
+    return idle_time / 1000000;  // nano to milli
+  }
+#else
+  static bool was_logged = false;
+  if (!was_logged) {
+    was_logged = true;
+    LOG(INFO) << "UserIdleTime unimplemented on this platform, "
+        "synchronization will not throttle when user idle";
+  }
+#endif
+
+  return 0;
+}
+
+}  // namespace
+
+namespace browser_sync {
+
+bool SyncerThread::NudgeSyncer(int milliseconds_from_now, NudgeSource source) {
+  MutexLock lock(&mutex_);
+  if (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(
+    ClientCommandChannel* command_channel,
+    syncable::DirectoryManager* mgr,
+    ServerConnectionManager* connection_manager,
+    AllStatus* all_status,
+    ModelSafeWorker* model_safe_worker)
+    : dirman_(mgr), scm_(connection_manager),
+      syncer_(NULL), syncer_events_(NULL), thread_running_(false),
+      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),
+      model_safe_worker_(model_safe_worker),
+      client_command_hookup_(NULL), disable_idle_detection_(false) {
+
+  SyncerEvent shutdown = { SyncerEvent::SHUTDOWN_USE_WITH_CARE };
+  syncer_event_channel_.reset(new SyncerEventChannel(shutdown));
+
+  if (dirman_) {
+    directory_manager_hookup_.reset(NewEventListenerHookup(
+        dirman_->channel(), this, &SyncerThread::HandleDirectoryManagerEvent));
+  }
+
+  if (scm_) {
+    WatchConnectionManager(scm_);
+  }
+
+  if (command_channel_) {
+    WatchClientCommands(command_channel_);
+  }
+}
+
+SyncerThread::~SyncerThread() {
+  client_command_hookup_.reset();
+  conn_mgr_hookup_.reset();
+  syncer_event_channel_.reset();
+  directory_manager_hookup_.reset();
+  syncer_events_.reset();
+  delete syncer_;
+  talk_mediator_hookup_.reset();
+  CHECK(!thread_running_);
+}
+
+// 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;
+  }
+  thread_running_ =
+    (0 == pthread_create(&thread_, NULL, RunSyncerThread, this));
+  if (thread_running_) {
+    pthread_detach(thread_);
+  }
+  return thread_running_;
+}
+
+// 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();
+  }
+  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_);
+  return true;
+}
+
+void SyncerThread::WatchClientCommands(ClientCommandChannel* channel) {
+  PThreadScopedLock<PThreadMutex> lock(&mutex_);
+  client_command_hookup_.reset(NewEventListenerHookup(channel, this,
+      &SyncerThread::HandleClientCommand));
+}
+
+void SyncerThread::HandleClientCommand(ClientCommandChannel::EventType
+                                       event) {
+  if (!event) {
+    return;
+  }
+
+  // mutex not really necessary for these
+  if (event->has_set_sync_poll_interval()) {
+    syncer_short_poll_interval_seconds_ = event->set_sync_poll_interval();
+  }
+
+  if (event->has_set_sync_long_poll_interval()) {
+    syncer_long_poll_interval_seconds_ = event->set_sync_long_poll_interval();
+  }
+}
+
+void SyncerThread::ThreadMainLoop() {
+  // Use the short poll value by default.
+  int poll_seconds = syncer_short_poll_interval_seconds_;
+  int user_idle_milliseconds = 0;
+  timespec last_sync_time = { 0 };
+  bool initial_sync_for_thread = true;
+  bool continue_sync_cycle = false;
+
+  while (!stop_syncer_thread_) {
+    if (!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.";
+      continue;
+    }
+
+    if (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.";
+      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 int error = pthread_cond_timedwait(&changed_.condvar_, &mutex_.mutex_,
+                                             &wake_time);
+    if (ETIMEDOUT != error) {
+      continue;  // Check all the conditions again.
+    }
+
+    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);
+
+    LOG(INFO) << "Calling Sync Main at time " << now.tv_sec;
+    SyncMain(syncer_);
+    last_sync_time = now;
+
+    LOG(INFO) << "Updating the next polling time after SyncMain";
+    poll_seconds = CalculatePollingWaitTime(allstatus_->status(),
+                                            poll_seconds,
+                                            &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.
+int SyncerThread::CalculatePollingWaitTime(
+    const AllStatus::Status& status,
+    int last_poll_wait,  // in s
+    int* user_idle_milliseconds,
+    bool* continue_sync_cycle) {
+  bool is_continuing_sync_cyle = *continue_sync_cycle;
+  *continue_sync_cycle = false;
+
+  // Determine if the syncer has unfinished work to do from allstatus_.
+  const bool syncer_has_work_to_do =
+    status.updates_available > status.updates_received
+    || status.unsynced_count > 0;
+  LOG(INFO) << "syncer_has_work_to_do is " << syncer_has_work_to_do;
+
+  // First calculate the expected wait time, figuring in any backoff because of
+  // user idle time.  next_wait is in seconds
+  syncer_polling_interval_ = (!status.notifications_enabled) ?
+      syncer_short_poll_interval_seconds_ :
+      syncer_long_poll_interval_seconds_;
+  int default_next_wait = syncer_polling_interval_;
+  int actual_next_wait = default_next_wait;
+
+  if (syncer_has_work_to_do) {
+    // Provide exponential backoff due to consecutive errors, else attempt to
+    // complete the work as soon as possible.
+    if (!is_continuing_sync_cyle) {
+      actual_next_wait = AllStatus::GetRecommendedDelaySeconds(0);
+    } else {
+      actual_next_wait = AllStatus::GetRecommendedDelaySeconds(last_poll_wait);
+    }
+    *continue_sync_cycle = true;
+  } else if (!status.notifications_enabled) {
+    // Ensure that we start exponential backoff from our base polling
+    // interval when we are not continuing a sync cycle.
+    last_poll_wait = std::max(last_poll_wait, syncer_polling_interval_);
+
+    // Did the user start interacting with the computer again?
+    // If so, revise our idle time (and probably next_sync_time) downwards
+    int new_idle_time = disable_idle_detection_ ? 0 : UserIdleTime();
+    if (new_idle_time < *user_idle_milliseconds) {
+      *user_idle_milliseconds = new_idle_time;
+    }
+    actual_next_wait = CalculateSyncWaitTime(last_poll_wait * 1000,
+                                              *user_idle_milliseconds) / 1000;
+    DCHECK_GE(actual_next_wait, default_next_wait);
+  }
+
+  LOG(INFO) << "Sync wait: idle " << default_next_wait
+            << " non-idle or backoff " << actual_next_wait << ".";
+
+  return actual_next_wait;
+}
+
+void* SyncerThread::ThreadMain() {
+  NameCurrentThreadForDebugging("SyncEngine_SyncerThread");
+  mutex_.Lock();
+  ThreadMainLoop();
+  thread_running_ = false;
+  pthread_cond_broadcast(&changed_.condvar_);
+  mutex_.Unlock();
+  LOG(INFO) << "Syncer thread exiting.";
+  return 0;
+}
+
+void SyncerThread::SyncMain(Syncer* syncer) {
+  CHECK(syncer);
+  mutex_.Unlock();
+  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,
+                                     bool* initial_sync) {
+  bool nudged = false;
+  NudgeSource nudge_source = kUnknown;
+  // Has the previous sync cycle completed?
+  if (continue_sync_cycle) {
+    nudge_source = kContinuation;
+  }
+  // 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)) {
+    if (!nudged) {
+      nudge_source = nudge_queue_.top().second;
+      *continue_sync_cycle = false;  //  Reset the continuation token on nudge.
+      nudged = true;
+    }
+    nudge_queue_.pop();
+  }
+  SetUpdatesSource(nudged, nudge_source, initial_sync);
+}
+
+void SyncerThread::SetUpdatesSource(bool nudged, NudgeSource nudge_source,
+                                    bool* initial_sync) {
+  sync_pb::GetUpdatesCallerInfo::GET_UPDATES_SOURCE updates_source =
+      sync_pb::GetUpdatesCallerInfo::UNKNOWN;
+  if (*initial_sync) {
+    updates_source = sync_pb::GetUpdatesCallerInfo::FIRST_UPDATE;
+    *initial_sync = false;
+  } else if (!nudged) {
+    updates_source = sync_pb::GetUpdatesCallerInfo::PERIODIC;
+  } else {
+    switch (nudge_source) {
+      case kNotification:
+        updates_source = sync_pb::GetUpdatesCallerInfo::NOTIFICATION;
+        break;
+      case kLocal:
+        updates_source = sync_pb::GetUpdatesCallerInfo::LOCAL;
+        break;
+      case kContinuation:
+        updates_source = sync_pb::GetUpdatesCallerInfo::SYNC_CYCLE_CONTINUATION;
+        break;
+      case kUnknown:
+      default:
+        updates_source = sync_pb::GetUpdatesCallerInfo::UNKNOWN;
+        break;
+    }
+  }
+  syncer_->set_updates_source(updates_source);
+}
+
+void SyncerThread::HandleSyncerEvent(const SyncerEvent& event) {
+  MutexLock lock(&mutex_);
+  channel()->NotifyListeners(event);
+  if (SyncerEvent::REQUEST_SYNC_NUDGE != event.what_happened) {
+    return;
+  }
+  NudgeSyncImpl(event.nudge_delay_milliseconds, kUnknown);
+}
+
+void SyncerThread::HandleDirectoryManagerEvent(
+    const syncable::DirectoryManagerEvent& event) {
+  LOG(INFO) << "Handling a directory manager event";
+  if (syncable::DirectoryManagerEvent::OPENED == event.what_happened) {
+    MutexLock lock(&mutex_);
+    LOG(INFO) << "Syncer starting up for: " << event.dirname;
+    // The underlying database structure is ready, and we should create
+    // the syncer.
+    CHECK(syncer_ == NULL);
+    syncer_ =
+        new Syncer(dirman_, event.dirname, scm_, model_safe_worker_.get());
+
+    syncer_->set_command_channel(command_channel_);
+    syncer_events_.reset(NewEventListenerHookup(
+        syncer_->channel(), this, &SyncerThread::HandleSyncerEvent));
+    pthread_cond_broadcast(&changed_.condvar_);
+  }
+}
+
+static inline void CheckConnected(bool* connected,
+                                  HttpResponse::ServerConnectionCode code,
+                                  pthread_cond_t* condvar) {
+  if (*connected) {
+    if (HttpResponse::CONNECTION_UNAVAILABLE == code) {
+      *connected = false;
+      pthread_cond_broadcast(condvar);
+    }
+  } else {
+    if (HttpResponse::SERVER_CONNECTION_OK == code) {
+      *connected = true;
+      pthread_cond_broadcast(condvar);
+    }
+  }
+}
+
+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_);
+}
+
+void SyncerThread::HandleServerConnectionEvent(
+    const ServerConnectionEvent& event) {
+  if (ServerConnectionEvent::STATUS_CHANGED == event.what_happened) {
+    MutexLock lock(&mutex_);
+    CheckConnected(&connected_, event.connection_code,
+                   &changed_.condvar_);
+  }
+}
+
+SyncerEventChannel* SyncerThread::channel() {
+  return syncer_event_channel_.get();
+}
+
+// inputs and return value in milliseconds
+int SyncerThread::CalculateSyncWaitTime(int last_interval, int user_idle_ms) {
+  // syncer_polling_interval_ is in seconds
+  int syncer_polling_interval_ms = syncer_polling_interval_ * 1000;
+
+  // This is our default and lower bound.
+  int next_wait = syncer_polling_interval_ms;
+
+  // Get idle time, bounded by max wait.
+  int idle = min(user_idle_ms, syncer_max_interval_);
+
+  // If the user has been idle for a while,
+  // we'll start decreasing the poll rate.
+  if (idle >= kPollBackoffThresholdMultiplier * syncer_polling_interval_ms) {
+    next_wait = std::min(AllStatus::GetRecommendedDelaySeconds(
+        last_interval / 1000), syncer_max_interval_ / 1000) * 1000;
+  }
+
+  return next_wait;
+}
+
+// Called with mutex_ already locked
+void SyncerThread::NudgeSyncImpl(int milliseconds_from_now,
+                                 NudgeSource source) {
+  const timespec nudge_time = GetPThreadAbsoluteTime(milliseconds_from_now);
+  NudgeObject nudge_object(nudge_time, source);
+  nudge_queue_.push(nudge_object);
+  pthread_cond_broadcast(&changed_.condvar_);
+}
+
+void SyncerThread::WatchTalkMediator(TalkMediator* mediator) {
+  talk_mediator_hookup_.reset(
+      NewEventListenerHookup(
+          mediator->channel(),
+          this,
+          &SyncerThread::HandleTalkMediatorEvent));
+}
+
+void SyncerThread::HandleTalkMediatorEvent(const TalkMediatorEvent& event) {
+  MutexLock lock(&mutex_);
+  switch (event.what_happened) {
+    case TalkMediatorEvent::LOGIN_SUCCEEDED:
+      LOG(INFO) << "P2P: Login succeeded.";
+      p2p_authenticated_ = true;
+      break;
+    case TalkMediatorEvent::LOGOUT_SUCCEEDED:
+      LOG(INFO) << "P2P: Login succeeded.";
+      p2p_authenticated_ = false;
+      break;
+    case TalkMediatorEvent::SUBSCRIPTIONS_ON:
+      LOG(INFO) << "P2P: Subscriptions successfully enabled.";
+      p2p_subscribed_ = true;
+      if (NULL != syncer_) {
+        LOG(INFO) << "Subscriptions on.  Nudging syncer for initial push.";
+        NudgeSyncImpl(0, kLocal);
+      }
+      break;
+    case TalkMediatorEvent::SUBSCRIPTIONS_OFF:
+      LOG(INFO) << "P2P: Subscriptions are not enabled.";
+      p2p_subscribed_ = false;
+      break;
+    case TalkMediatorEvent::NOTIFICATION_RECEIVED:
+      LOG(INFO) << "P2P: Updates on server, pushing syncer";
+      if (NULL != syncer_) {
+        NudgeSyncImpl(0, kNotification);
+      }
+      break;
+    default:
+      break;
+  }
+
+  if (NULL != syncer_) {
+    syncer_->set_notifications_enabled(p2p_authenticated_ && p2p_subscribed_);
+  }
+}
+
+}  // namespace browser_sync