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

chrome/browser/sync/engine/syncer.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 entry.
+
+#ifndef CHROME_BROWSER_SYNC_ENGINE_SYNCER_H_
+#define CHROME_BROWSER_SYNC_ENGINE_SYNCER_H_
+
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/scoped_ptr.h"
+#include "chrome/browser/sync/engine/client_command_channel.h"
+#include "chrome/browser/sync/engine/conflict_resolver.h"
+#include "chrome/browser/sync/engine/syncer_types.h"
+#include "chrome/browser/sync/engine/syncproto.h"
+#include "chrome/browser/sync/syncable/directory_event.h"
+#include "chrome/browser/sync/util/event_sys-inl.h"
+#include "chrome/browser/sync/util/event_sys.h"
+#include "chrome/browser/sync/util/pthread_helpers.h"
+#include "testing/gtest/include/gtest/gtest_prod.h"  // For FRIEND_TEST
+
+namespace syncable {
+class Directory;
+class DirectoryManager;
+class Entry;
+class Id;
+class MutableEntry;
+class WriteTransaction;
+}  // namespace syncable
+
+namespace browser_sync {
+
+class ModelSafeWorker;
+class ServerConnectionManager;
+class SyncProcessState;
+class SyncerSession;
+class URLFactory;
+struct HttpResponse;
+
+static const int kDefaultMaxCommitBatchSize = 25;
+
+enum SyncerStep {
+  SYNCER_BEGIN,
+  DOWNLOAD_UPDATES,
+  PROCESS_CLIENT_COMMAND,
+  VERIFY_UPDATES,
+  PROCESS_UPDATES,
+  APPLY_UPDATES,
+  BUILD_COMMIT_REQUEST,
+  POST_COMMIT_MESSAGE,
+  PROCESS_COMMIT_RESPONSE,
+  BUILD_AND_PROCESS_CONFLICT_SETS,
+  RESOLVE_CONFLICTS,
+  APPLY_UPDATES_TO_RESOLVE_CONFLICTS,
+  SYNCER_END
+};
+
+// A Syncer provides a control interface for driving the individual steps
+// of the sync cycle.  Each cycle (hopefully) moves the client into closer
+// synchronization with the server.  The individual steps are modeled
+// as SyncerCommands, and the ordering of the steps is expressed using
+// the SyncerStep enum.
+//
+// A Syncer instance expects to run on a dedicated thread.  Calls
+// to SyncShare() may take an unbounded amount of time, as SyncerCommands
+// may block on network i/o, on lock contention, or on tasks posted to
+// other threads.
+class Syncer {
+ public:
+  typedef std::vector<int64> UnsyncedMetaHandles;
+  typedef void (*TestCallbackFunction)(syncable::Directory* dir);
+
+  // The constructor may be called from a thread that is not the Syncer's
+  // dedicated thread, to allow some flexibility in the setup.
+  Syncer(
+      syncable::DirectoryManager* dirman,
+      const PathString &account_name,
+      ServerConnectionManager* connection_manager,
+      ModelSafeWorker* model_safe_worker);
+
+  ~Syncer();
+
+  // Called by other threads to tell the syncer to stop what it's doing
+  // and return early from SyncShare, if possible.
+  bool ExitRequested() { return early_exit_requested_; }
+  void RequestEarlyExit() { early_exit_requested_ = true; }
+
+  // SyncShare(...) variants cause one sync cycle to occur.  The return value
+  // indicates whether we should sync again.
+  // The zero-argument version of SyncShare is provided for unit tests.
+  // When |sync_process_state| is provided, it is used as the syncer state
+  // for the sync cycle.  It is treated as an input/output parameter.
+  // When |first_step| and |last_step| are provided, this means to perform
+  // a partial sync cycle, stopping after |last_step| is performed.
+  bool SyncShare();
+  bool SyncShare(SyncProcessState *sync_process_state);
+  bool SyncShare(SyncerStep first_step, SyncerStep last_step);
+
+  // Limit the batch size of commit operations to a specified number of items.
+  void set_max_commit_batch_size(int x) { max_commit_batch_size_ = x; }
+
+  ConflictResolver* conflict_resolver() { return &resolver_; }
+
+  PathString account_name() { return account_name_; }
+
+  SyncerEventChannel* channel() const { return syncer_event_channel_.get(); }
+
+  ShutdownChannel* shutdown_channel() const { return shutdown_channel_.get(); }
+
+  ModelSafeWorker* model_safe_worker() { return model_safe_worker_; }
+
+  // Syncer will take ownership of this channel and it will be destroyed along
+  // with the Syncer instance.
+  void set_shutdown_channel(ShutdownChannel* channel) {
+    shutdown_channel_.reset(channel);
+  }
+
+  void set_command_channel(ClientCommandChannel* channel) {
+    command_channel_ = channel;
+  }
+
+  // Volatile reader for the source member of the syncer session object.  The
+  // value is set to the SYNC_CYCLE_CONTINUATION value to signal that it has
+  // been read.
+  sync_pb::GetUpdatesCallerInfo::GET_UPDATES_SOURCE TestAndSetUpdatesSource() {
+    sync_pb::GetUpdatesCallerInfo::GET_UPDATES_SOURCE old_source =
+        updates_source_;
+    set_updates_source(sync_pb::GetUpdatesCallerInfo::SYNC_CYCLE_CONTINUATION);
+    return old_source;
+  }
+
+  void set_updates_source(
+      sync_pb::GetUpdatesCallerInfo::GET_UPDATES_SOURCE source) {
+    updates_source_ = source;
+  }
+
+  bool notifications_enabled() const {
+    return notifications_enabled_;
+  }
+
+  void set_notifications_enabled(bool state) {
+    notifications_enabled_ = state;
+  }
+
+ private:
+  void RequestNudge(int milliseconds);
+
+  // Implements the PROCESS_CLIENT_COMMAND syncer step.
+  void ProcessClientCommand(SyncerSession *session);
+
+  void SyncShare(SyncerSession* session);
+  void SyncShare(SyncerSession* session,
+                 SyncerStep first_step,
+                 SyncerStep last_step);
+
+  PathString account_name_;
+  bool early_exit_requested_;
+
+  int32 max_commit_batch_size_;
+
+  ServerConnectionManager* connection_manager_;
+
+  ConflictResolver resolver_;
+  syncable::DirectoryManager* const dirman_;
+
+  // When we're over bandwidth quota, we don't update until past this time.
+  time_t silenced_until_;
+
+  scoped_ptr<SyncerEventChannel> syncer_event_channel_;
+  scoped_ptr<ShutdownChannel> shutdown_channel_;
+  ClientCommandChannel* command_channel_;
+
+  // A worker capable of processing work closures on a thread that is
+  // guaranteed to be safe for model modifications. This is created and owned
+  // by the SyncerThread that created us.
+  ModelSafeWorker* model_safe_worker_;
+
+  // The source of the last nudge.
+  sync_pb::GetUpdatesCallerInfo::GET_UPDATES_SOURCE updates_source_;
+
+  // True only if the notification channel is authorized and open.
+  bool notifications_enabled_;
+
+  // A callback hook used in unittests to simulate changes between conflict set
+  // building and conflict resolution.
+  TestCallbackFunction pre_conflict_resolution_function_;
+
+  FRIEND_TEST(SyncerTest, NewServerItemInAFolderHierarchyWeHaveDeleted3);
+  FRIEND_TEST(SyncerTest, TestCommitListOrderingAndNewParent);
+  FRIEND_TEST(SyncerTest, TestCommitListOrderingAndNewParentAndChild);
+  FRIEND_TEST(SyncerTest, TestCommitListOrderingCounterexample);
+  FRIEND_TEST(SyncerTest, TestCommitListOrderingWithNesting);
+  FRIEND_TEST(SyncerTest, TestCommitListOrderingWithNewItems);
+  FRIEND_TEST(SyncerTest, TestGetUnsyncedAndSimpleCommit);
+
+  DISALLOW_COPY_AND_ASSIGN(Syncer);
+};
+
+// Inline utility functions.
+
+// Given iterator ranges from two collections sorted according to a
+// common strict weak ordering, return true if the two ranges contain
+// any common items, and false if they do not.
+// This function is in this header so that it can be tested.
+template <class Iterator1, class Iterator2>
+bool SortedCollectionsIntersect(Iterator1 begin1, Iterator1 end1,
+                                Iterator2 begin2, Iterator2 end2) {
+  Iterator1 i1 = begin1;
+  Iterator2 i2 = begin2;
+  while (i1 != end1 && i2 != end2) {
+    if (*i1 == *i2)
+      return true;
+    if (*i1 > *i2)
+      ++i2;
+    else
+      ++i1;
+  }
+  return false;
+}
+// Utility function declarations.
+void SplitServerInformationIntoNewEntry(syncable::WriteTransaction* trans,
+                                        syncable::MutableEntry* entry);
+void CopyServerFields(syncable::Entry* src, syncable::MutableEntry* dest);
+void ClearServerData(syncable::MutableEntry* entry);
+
+// Get update contents as a string. Intended for logging, and intended
+// to have a smaller footprint than the protobuf's built-in pretty printer.
+std::string SyncEntityDebugString(const sync_pb::SyncEntity& entry);
+
+}  // namespace browser_sync
+
+#endif  // CHROME_BROWSER_SYNC_ENGINE_SYNCER_H_