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// Copyright (c) 2012 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 <stdint.h>
#include <utility>
#include <vector>
#include "base/callback.h"
#include "base/gtest_prod_util.h"
#include "base/macros.h"
#include "base/synchronization/lock.h"
#include "sync/base/sync_export.h"
#include "sync/engine/conflict_resolver.h"
#include "sync/engine/syncer_types.h"
#include "sync/internal_api/public/base/model_type.h"
#include "sync/sessions/sync_session.h"
#include "sync/util/extensions_activity.h"
namespace syncer {
class CancelationSignal;
class CommitProcessor;
class GetUpdatesProcessor;
// A Syncer provides a control interface for driving the sync cycle. These
// cycles consist of downloading updates, parsing the response (aka. process
// updates), applying updates while resolving conflicts, and committing local
// changes. Some of these steps may be skipped if they're deemed to be
// unnecessary.
// A Syncer instance expects to run on a dedicated thread. Calls to SyncShare()
// may take an unbounded amount of time because it may block on network I/O, on
// lock contention, or on tasks posted to other threads.
class SYNC_EXPORT Syncer {
typedef std::vector<int64_t> UnsyncedMetaHandles;
explicit Syncer(CancelationSignal* cancelation_signal);
virtual ~Syncer();
// Whether an early exist was requested due to a cancelation signal.
bool ExitRequested();
// Whether the syncer is in the middle of a sync cycle.
bool IsSyncing() const;
// Fetches and applies updates, resolves conflicts and commits local changes
// for |request_types| as necessary until client and server states are in
// sync. The |nudge_tracker| contains state that describes why the client is
// out of sync and what must be done to bring it back into sync.
// Returns: false if an error occurred and retries should backoff, true
// otherwise.
virtual bool NormalSyncShare(ModelTypeSet request_types,
sessions::NudgeTracker* nudge_tracker,
sessions::SyncSession* session);
// Performs an initial download for the |request_types|. It is assumed that
// the specified types have no local state, and that their associated change
// processors are in "passive" mode, so none of the downloaded updates will be
// applied to the model. The |source| is sent up to the server for debug
// purposes. It describes the reson for performing this initial download.
// Returns: false if an error occurred and retries should backoff, true
// otherwise.
virtual bool ConfigureSyncShare(
ModelTypeSet request_types,
sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source,
sessions::SyncSession* session);
// Requests to download updates for the |request_types|. For a well-behaved
// client with a working connection to the invalidations server, this should
// be unnecessary. It may be invoked periodically to try to keep the client
// in sync despite bugs or transient failures.
// Returns: false if an error occurred and retries should backoff, true
// otherwise.
virtual bool PollSyncShare(ModelTypeSet request_types,
sessions::SyncSession* session);
// Posts a ClearServerData command.
// Returns: false if an error occurred and retries should backoff, true
// otherwise.
virtual bool PostClearServerData(sessions::SyncSession* session);
friend class SyncerTest;
FRIEND_TEST_ALL_PREFIXES(SyncerTest, NameClashWithResolver);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, IllegalAndLegalUpdates);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingAndNewParent);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingCounterexample);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingWithNesting);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingWithNewItems);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestGetUnsyncedAndSimpleCommit);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestPurgeWhileUnsynced);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestPurgeWhileUnapplied);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, UnappliedUpdateDuringCommit);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, DeletingEntryInFolder);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, QuicklyMergeDualCreatedHierarchy);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, LongChangelistWithApplicationConflict);
FRIEND_TEST_ALL_PREFIXES(SyncerTest, DeletingEntryWithLocalEdits);
bool DownloadAndApplyUpdates(
ModelTypeSet* request_types,
sessions::SyncSession* session,
GetUpdatesProcessor* get_updates_processor,
bool create_mobile_bookmarks_folder);
// This function will commit batches of unsynced items to the server until the
// number of unsynced and ready to commit items reaches zero or an error is
// encountered. A request to exit early will be treated as an error and will
// abort any blocking operations.
SyncerError BuildAndPostCommits(ModelTypeSet request_types,
sessions::NudgeTracker* nudge_tracker,
sessions::SyncSession* session,
CommitProcessor* commit_processor);
void HandleCycleBegin(sessions::SyncSession* session);
bool HandleCycleEnd(
sessions::SyncSession* session,
sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source);
syncer::CancelationSignal* const cancelation_signal_;
// Whether the syncer is in the middle of a sync attempt.
bool is_syncing_;
} // namespace syncer