Home | History | Annotate | Download | only in engine 
      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef SYNC_ENGINE_SYNCER_H_
      6 #define SYNC_ENGINE_SYNCER_H_
      7 
      8 #include <utility>
      9 #include <vector>
     10 
     11 #include "base/basictypes.h"
     12 #include "base/callback.h"
     13 #include "base/gtest_prod_util.h"
     14 #include "base/synchronization/lock.h"
     15 #include "sync/base/sync_export.h"
     16 #include "sync/engine/conflict_resolver.h"
     17 #include "sync/engine/syncer_types.h"
     18 #include "sync/internal_api/public/base/model_type.h"
     19 #include "sync/sessions/sync_session.h"
     20 #include "sync/util/extensions_activity.h"
     21 
     22 namespace syncer {
     23 
     24 class CancelationSignal;
     25 class CommitProcessor;
     26 class GetUpdatesProcessor;
     27 
     28 // A Syncer provides a control interface for driving the sync cycle.  These
     29 // cycles consist of downloading updates, parsing the response (aka. process
     30 // updates), applying updates while resolving conflicts, and committing local
     31 // changes.  Some of these steps may be skipped if they're deemed to be
     32 // unnecessary.
     33 //
     34 // A Syncer instance expects to run on a dedicated thread.  Calls to SyncShare()
     35 // may take an unbounded amount of time because it may block on network I/O, on
     36 // lock contention, or on tasks posted to other threads.
     37 class SYNC_EXPORT_PRIVATE Syncer {
     38  public:
     39   typedef std::vector<int64> UnsyncedMetaHandles;
     40 
     41   Syncer(CancelationSignal* cancelation_signal);
     42   virtual ~Syncer();
     43 
     44   bool ExitRequested();
     45 
     46   // Fetches and applies updates, resolves conflicts and commits local changes
     47   // for |request_types| as necessary until client and server states are in
     48   // sync.  The |nudge_tracker| contains state that describes why the client is
     49   // out of sync and what must be done to bring it back into sync.
     50   virtual bool NormalSyncShare(ModelTypeSet request_types,
     51                                const sessions::NudgeTracker& nudge_tracker,
     52                                sessions::SyncSession* session);
     53 
     54   // Performs an initial download for the |request_types|.  It is assumed that
     55   // the specified types have no local state, and that their associated change
     56   // processors are in "passive" mode, so none of the downloaded updates will be
     57   // applied to the model.  The |source| is sent up to the server for debug
     58   // purposes.  It describes the reson for performing this initial download.
     59   virtual bool ConfigureSyncShare(
     60       ModelTypeSet request_types,
     61       sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source,
     62       sessions::SyncSession* session);
     63 
     64   // Requests to download updates for the |request_types|.  For a well-behaved
     65   // client with a working connection to the invalidations server, this should
     66   // be unnecessary.  It may be invoked periodically to try to keep the client
     67   // in sync despite bugs or transient failures.
     68   virtual bool PollSyncShare(ModelTypeSet request_types,
     69                              sessions::SyncSession* session);
     70 
     71  private:
     72   bool DownloadAndApplyUpdates(
     73       ModelTypeSet request_types,
     74       sessions::SyncSession* session,
     75       GetUpdatesProcessor* get_updates_processor,
     76       bool create_mobile_bookmarks_folder);
     77 
     78   // This function will commit batches of unsynced items to the server until the
     79   // number of unsynced and ready to commit items reaches zero or an error is
     80   // encountered.  A request to exit early will be treated as an error and will
     81   // abort any blocking operations.
     82   SyncerError BuildAndPostCommits(
     83       ModelTypeSet request_types,
     84       sessions::SyncSession* session,
     85       CommitProcessor* commit_processor);
     86 
     87   void HandleCycleBegin(sessions::SyncSession* session);
     88   bool HandleCycleEnd(
     89       sessions::SyncSession* session,
     90       sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source);
     91 
     92   syncer::CancelationSignal* const cancelation_signal_;
     93 
     94   friend class SyncerTest;
     95   FRIEND_TEST_ALL_PREFIXES(SyncerTest, NameClashWithResolver);
     96   FRIEND_TEST_ALL_PREFIXES(SyncerTest, IllegalAndLegalUpdates);
     97   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingAndNewParent);
     98   FRIEND_TEST_ALL_PREFIXES(SyncerTest,
     99                            TestCommitListOrderingAndNewParentAndChild);
    100   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingCounterexample);
    101   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingWithNesting);
    102   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingWithNewItems);
    103   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestGetUnsyncedAndSimpleCommit);
    104   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestPurgeWhileUnsynced);
    105   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestPurgeWhileUnapplied);
    106   FRIEND_TEST_ALL_PREFIXES(SyncerTest, UnappliedUpdateDuringCommit);
    107   FRIEND_TEST_ALL_PREFIXES(SyncerTest, DeletingEntryInFolder);
    108   FRIEND_TEST_ALL_PREFIXES(SyncerTest,
    109                            LongChangelistCreatesFakeOrphanedEntries);
    110   FRIEND_TEST_ALL_PREFIXES(SyncerTest, QuicklyMergeDualCreatedHierarchy);
    111   FRIEND_TEST_ALL_PREFIXES(SyncerTest, LongChangelistWithApplicationConflict);
    112   FRIEND_TEST_ALL_PREFIXES(SyncerTest, DeletingEntryWithLocalEdits);
    113   FRIEND_TEST_ALL_PREFIXES(EntryCreatedInNewFolderTest,
    114                            EntryCreatedInNewFolderMidSync);
    115 
    116   DISALLOW_COPY_AND_ASSIGN(Syncer);
    117 };
    118 
    119 }  // namespace syncer
    120 
    121 #endif  // SYNC_ENGINE_SYNCER_H_
    122