sync/engine/syncer.h

   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
  26 // A Syncer provides a control interface for driving the individual steps
  27 // of the sync cycle.  Each cycle (hopefully) moves the client into closer
  28 // synchronization with the server.  The individual steps are modeled
  29 // as SyncerCommands, and the ordering of the steps is expressed using
  30 // the SyncerStep enum.
  31 //
  32 // A Syncer instance expects to run on a dedicated thread.  Calls
  33 // to SyncShare() may take an unbounded amount of time, as SyncerCommands
  34 // may block on network i/o, on lock contention, or on tasks posted to
  35 // other threads.
  36 class SYNC_EXPORT_PRIVATE Syncer {
  37  public:
  38   typedef std::vector<int64> UnsyncedMetaHandles;
  39
  40   Syncer(CancelationSignal* cancelation_signal);
  41   virtual ~Syncer();
  42
  43   bool ExitRequested();
  44
  45   // Fetches and applies updates, resolves conflicts and commits local changes
  46   // for |request_types| as necessary until client and server states are in
  47   // sync.  The |nudge_tracker| contains state that describes why the client is
  48   // out of sync and what must be done to bring it back into sync.
  49   virtual bool NormalSyncShare(ModelTypeSet request_types,
  50                                const sessions::NudgeTracker& nudge_tracker,
  51                                sessions::SyncSession* session);
  52
  53   // Performs an initial download for the |request_types|.  It is assumed that
  54   // the specified types have no local state, and that their associated change
  55   // processors are in "passive" mode, so none of the downloaded updates will be
  56   // applied to the model.  The |source| is sent up to the server for debug
  57   // purposes.  It describes the reson for performing this initial download.
  58   virtual bool ConfigureSyncShare(
  59       ModelTypeSet request_types,
  60       sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source,
  61       sessions::SyncSession* session);
  62
  63   // Requests to download updates for the |request_types|.  For a well-behaved
  64   // client with a working connection to the invalidations server, this should
  65   // be unnecessary.  It may be invoked periodically to try to keep the client
  66   // in sync despite bugs or transient failures.
  67   virtual bool PollSyncShare(ModelTypeSet request_types,
  68                              sessions::SyncSession* session);
  69
  70  private:
  71   void ApplyUpdates(sessions::SyncSession* session);
  72   bool DownloadAndApplyUpdates(
  73       sessions::SyncSession* session,
  74       base::Callback<void(sync_pb::ClientToServerMessage*)> build_fn);
  75
  76   // This function will commit batches of unsynced items to the server until the
  77   // number of unsynced and ready to commit items reaches zero or an error is
  78   // encountered.  A request to exit early will be treated as an error and will
  79   // abort any blocking operations.
  80   SyncerError BuildAndPostCommits(
  81       ModelTypeSet request_types,
  82       sessions::SyncSession* session);
  83
  84   void HandleCycleBegin(sessions::SyncSession* session);
  85   bool HandleCycleEnd(
  86       sessions::SyncSession* session,
  87       sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source);
  88
  89   syncer::CancelationSignal* const cancelation_signal_;
  90
  91   friend class SyncerTest;
  92   FRIEND_TEST_ALL_PREFIXES(SyncerTest, NameClashWithResolver);
  93   FRIEND_TEST_ALL_PREFIXES(SyncerTest, IllegalAndLegalUpdates);
  94   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingAndNewParent);
  95   FRIEND_TEST_ALL_PREFIXES(SyncerTest,
  96                            TestCommitListOrderingAndNewParentAndChild);
  97   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingCounterexample);
  98   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingWithNesting);
  99   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingWithNewItems);
 100   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestGetUnsyncedAndSimpleCommit);
 101   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestPurgeWhileUnsynced);
 102   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestPurgeWhileUnapplied);
 103   FRIEND_TEST_ALL_PREFIXES(SyncerTest, UnappliedUpdateDuringCommit);
 104   FRIEND_TEST_ALL_PREFIXES(SyncerTest, DeletingEntryInFolder);
 105   FRIEND_TEST_ALL_PREFIXES(SyncerTest,
 106                            LongChangelistCreatesFakeOrphanedEntries);
 107   FRIEND_TEST_ALL_PREFIXES(SyncerTest, QuicklyMergeDualCreatedHierarchy);
 108   FRIEND_TEST_ALL_PREFIXES(SyncerTest, LongChangelistWithApplicationConflict);
 109   FRIEND_TEST_ALL_PREFIXES(SyncerTest, DeletingEntryWithLocalEdits);
 110   FRIEND_TEST_ALL_PREFIXES(EntryCreatedInNewFolderTest,
 111                            EntryCreatedInNewFolderMidSync);
 112
 113   DISALLOW_COPY_AND_ASSIGN(Syncer);
 114 };
 115
 116 }  // namespace syncer
 117
 118 #endif  // SYNC_ENGINE_SYNCER_H_