Initial commit of sync engine code to browser/sync....

chrome/browser/sync/engine/syncer_thread.h

+// 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.
+//
+// A class to run the syncer on a thread.
+//
+
+#ifndef CHROME_BROWSER_SYNC_ENGINE_SYNCER_THREAD_H_
+#define CHROME_BROWSER_SYNC_ENGINE_SYNCER_THREAD_H_
+
+#include <list>
+#include <map>
+#include <queue>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/scoped_ptr.h"
+#include "chrome/browser/sync/engine/all_status.h"
+#include "chrome/browser/sync/engine/client_command_channel.h"
+#include "chrome/browser/sync/util/event_sys-inl.h"
+#include "chrome/browser/sync/util/pthread_helpers.h"
+#include "testing/gtest/include/gtest/gtest_prod.h"  // For FRIEND_TEST
+
+class EventListenerHookup;
+
+namespace syncable {
+class DirectoryManager;
+struct DirectoryManagerEvent;
+}
+
+namespace browser_sync {
+
+class ModelSafeWorker;
+class ServerConnectionManager;
+class Syncer;
+class TalkMediator;
+class URLFactory;
+struct ServerConnectionEvent;
+struct SyncerEvent;
+struct SyncerShutdownEvent;
+struct TalkMediatorEvent;
+
+class SyncerThread {
+  FRIEND_TEST(SyncerThreadTest, CalculateSyncWaitTime);
+  FRIEND_TEST(SyncerThreadTest, CalculatePollingWaitTime);
+
+ public:
+  friend class SyncerThreadTest;
+
+  enum NudgeSource {
+    kUnknown = 0,
+    kNotification,
+    kLocal,
+    kContinuation
+  };
+
+  // Server can overwrite these values via client commands.
+  // Standard short poll. This is used when XMPP is off.
+  static const int kDefaultShortPollIntervalSeconds = 60;
+  // Long poll is used when XMPP is on.
+  static const int kDefaultLongPollIntervalSeconds = 3600;
+  // 30 minutes by default. If exponential backoff kicks in, this is
+  // the longest possible poll interval.
+  static const int kDefaultMaxPollIntervalMs = 30 * 60 * 1000;
+
+  SyncerThread(
+      ClientCommandChannel* command_channel,
+      syncable::DirectoryManager* mgr,
+      ServerConnectionManager* connection_manager,
+      AllStatus* all_status,
+      ModelSafeWorker* model_safe_worker);
+  ~SyncerThread();
+
+  void WatchConnectionManager(ServerConnectionManager* conn_mgr);
+  // 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 Start();
+
+  // Stop processing. A max wait of at least 2*server RTT time is recommended.
+  // returns true if we stopped, false otherwise.
+  bool Stop(int max_wait);
+
+  // Nudges the syncer to sync with a delay specified.  This API is for access
+  // from the SyncerThread's controller and will cause a mutex lock.
+  bool NudgeSyncer(int milliseconds_from_now, NudgeSource source);
+
+  // Registers this thread to watch talk mediator events.
+  void WatchTalkMediator(TalkMediator* talk_mediator);
+
+  void WatchClientCommands(ClientCommandChannel* channel);
+
+  SyncerEventChannel* channel();
+
+ private:
+  // A few members to gate the rate at which we nudge the syncer.
+  enum {
+    kNudgeRateLimitCount = 6,
+    kNudgeRateLimitTime = 180,
+  };
+
+  // A queue of all scheduled nudges.  One insertion for every call to
+  // NudgeQueue().
+  typedef std::pair<timespec, NudgeSource> NudgeObject;
+
+  struct IsTimeSpecGreater {
+    inline bool operator() (const NudgeObject& lhs, const NudgeObject& rhs) {
+      return lhs.first.tv_sec == rhs.first.tv_sec ?
+          lhs.first.tv_nsec > rhs.first.tv_nsec :
+          lhs.first.tv_sec > rhs.first.tv_sec;
+    }
+  };
+
+  typedef std::priority_queue<NudgeObject,
+                              std::vector<NudgeObject>, IsTimeSpecGreater>
+    NudgeQueue;
+
+  // Threshold multipler for how long before user should be considered idle.
+  static const int kPollBackoffThresholdMultiplier = 10;
+
+  friend void* RunSyncerThread(void* syncer_thread);
+  void* Run();
+  void HandleDirectoryManagerEvent(
+      const syncable::DirectoryManagerEvent& event);
+  void HandleSyncerEvent(const SyncerEvent& event);
+  void HandleClientCommand(ClientCommandChannel::EventType event);
+
+  void HandleServerConnectionEvent(const ServerConnectionEvent& event);
+
+  void HandleTalkMediatorEvent(const TalkMediatorEvent& event);
+
+  void* ThreadMain();
+  void ThreadMainLoop();
+
+  void SyncMain(Syncer* syncer);
+
+  // Calculates the next sync wait time in seconds.  last_poll_wait is the time
+  // duration of the previous polling timeout which was used.
+  // user_idle_milliseconds is updated by this method, and is a report of the
+  // full amount of time since the last period of activity for the user.  The
+  // continue_sync_cycle parameter is used to determine whether or not we are
+  // calculating a polling wait time that is a continuation of an sync cycle
+  // which terminated while the syncer still had work to do.
+  int CalculatePollingWaitTime(
+      const AllStatus::Status& status,
+      int last_poll_wait,  // in s
+      int* user_idle_milliseconds,
+      bool* continue_sync_cycle);
+  // Helper to above function, considers effect of user idle time.
+  int CalculateSyncWaitTime(int last_wait, int user_idle_ms);
+
+  // Sets the source value of the controlled syncer's updates_source value.
+  // The initial sync boolean is updated if read as a sentinel.  The following
+  // two methods work in concert to achieve this goal.
+  void UpdateNudgeSource(const timespec& now, bool* continue_sync_cycle,
+                         bool* initial_sync);
+  void SetUpdatesSource(bool nudged, NudgeSource nudge_source,
+                        bool* initial_sync);
+
+  // for unit tests only
+  void DisableIdleDetection() { disable_idle_detection_ = true; }
+
+  // false when we want to stop the thread.
+  bool stop_syncer_thread_;
+
+  // we use one mutex for all members except the channel.
+  PThreadMutex mutex_;
+  typedef PThreadScopedLock<PThreadMutex> MutexLock;
+
+  // Handle of the running thread.
+  pthread_t thread_;
+  bool thread_running_;
+
+  // Gets signaled whenever a thread outside of the syncer thread
+  // changes a member variable.
+  PThreadCondVar changed_;
+
+  // State of the server connection
+  bool connected_;
+
+  // State of the notification framework is tracked by these values.
+  bool p2p_authenticated_;
+  bool p2p_subscribed_;
+
+  scoped_ptr<EventListenerHookup> client_command_hookup_;
+  scoped_ptr<EventListenerHookup> conn_mgr_hookup_;
+  const AllStatus* allstatus_;
+
+  Syncer* syncer_;
+
+  syncable::DirectoryManager* dirman_;
+  ServerConnectionManager* scm_;
+
+  // Modifiable versions of kDefaultLongPollIntervalSeconds which can be
+  // updated by the server.
+  int syncer_short_poll_interval_seconds_;
+  int syncer_long_poll_interval_seconds_;
+
+  // The time we wait between polls in seconds. This is used as lower bound on
+  // our wait time. Updated once per loop from the command line flag.
+  int syncer_polling_interval_;
+
+  // The upper bound on the nominal wait between polls in seconds. Note that
+  // this bounds the "nominal" poll interval, while the the actual interval
+  // also takes previous failures into account.
+  int syncer_max_interval_;
+
+  scoped_ptr<SyncerEventChannel> syncer_event_channel_;
+
+  // This causes syncer to start syncing ASAP. If the rate of requests is
+  // too high the request will be silently dropped.  mutex_ should be held when
+  // this is called.
+  void NudgeSyncImpl(int milliseconds_from_now, NudgeSource source);
+
+  NudgeQueue nudge_queue_;
+
+  scoped_ptr<EventListenerHookup> talk_mediator_hookup_;
+  ClientCommandChannel* const command_channel_;
+  scoped_ptr<EventListenerHookup> directory_manager_hookup_;
+  scoped_ptr<EventListenerHookup> syncer_events_;
+
+  // Handles any tasks that will result in model changes (modifications of
+  // syncable::Entries). Pass this to the syncer created and managed by |this|.
+  // Only non-null in syncapi case.
+  scoped_ptr<ModelSafeWorker> model_safe_worker_;
+
+  // Useful for unit tests
+  bool disable_idle_detection_;
+
+  DISALLOW_COPY_AND_ASSIGN(SyncerThread);
+};
+
+}  // namespace browser_sync
+
+#endif  // CHROME_BROWSER_SYNC_ENGINE_SYNCER_THREAD_H_