1 // Copyright 2013 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_SYNCABLE_SYNCABLE_DELETE_JOURNAL_H_ 6 #define SYNC_SYNCABLE_SYNCABLE_DELETE_JOURNAL_H_ 7 8 #include <set> 9 10 #include "base/gtest_prod_util.h" 11 #include "base/synchronization/lock.h" 12 #include "sync/base/sync_export.h" 13 #include "sync/syncable/metahandle_set.h" 14 #include "sync/syncable/syncable-inl.h" 15 16 namespace syncer { 17 namespace syncable { 18 19 class BaseTransaction; 20 struct EntryKernel; 21 22 typedef std::set<const EntryKernel*, LessField<IdField, ID> > JournalIndex; 23 24 // DeleteJournal manages deleted entries that are not in sync directory until 25 // it's safe to drop them after the deletion is confirmed with native models. 26 // DeleteJournal is thread-safe and can be accessed on any thread. Has to hold 27 // a valid transaction object when calling methods of DeleteJournal, thus each 28 // method requires a non-null |trans| parameter. 29 class SYNC_EXPORT_PRIVATE DeleteJournal { 30 public: 31 FRIEND_TEST_ALL_PREFIXES(SyncableDirectoryTest, ManageDeleteJournals); 32 33 // Initialize |delete_journals_| using |intitial_journal|, whose content is 34 // destroyed during initialization. 35 explicit DeleteJournal(JournalIndex* initial_journal); 36 ~DeleteJournal(); 37 38 // For testing only. 39 size_t GetDeleteJournalSize(BaseTransaction* trans) const; 40 41 // Add/remove |entry| to/from |delete_journals_| according to its 42 // SERVER_IS_DEL field and |was_deleted|. Called on sync thread. 43 void UpdateDeleteJournalForServerDelete(BaseTransaction* trans, 44 bool was_deleted, 45 const EntryKernel& entry); 46 47 // Return entries of specified type in |delete_journals_|. This should be 48 // called ONCE in model association. |deleted_entries| can be used to 49 // detect deleted sync data that's not persisted in native model to 50 // prevent back-from-dead problem. |deleted_entries| are only valid during 51 // lifetime of |trans|. |type| is added to |passive_delete_journal_types_| to 52 // enable periodically saving/clearing of delete journals of |type| because 53 // new journals added later are not needed until next model association. 54 // Can be called on any thread. 55 void GetDeleteJournals(BaseTransaction* trans, ModelType type, 56 EntryKernelSet* deleted_entries); 57 58 // Purge entries of specified type in |delete_journals_| if their handles are 59 // in |to_purge|. This should be called after model association and 60 // |to_purge| should contain handles of the entries whose deletions are 61 // confirmed in native model. Can be called on any thread. 62 void PurgeDeleteJournals(BaseTransaction* trans, 63 const MetahandleSet& to_purge); 64 65 // Move entries in |delete_journals_| whose types are in 66 // |passive_delete_journal_types_| to |journal_entries|. Move handles in 67 // |delete_journals_to_purge_| to |journals_to_purge|. Called on sync thread. 68 void TakeSnapshotAndClear(BaseTransaction* trans, 69 EntryKernelSet* journal_entries, 70 MetahandleSet* journals_to_purge); 71 72 // Add |entries| to |delete_journals_| regardless of their SERVER_IS_DEL 73 // value. This is used to: 74 // * restore delete journals from snapshot if snapshot failed to save. 75 // * batch add entries of a data type with unrecoverable error to delete 76 // journal before purging them. 77 // Called on sync thread. 78 void AddJournalBatch(BaseTransaction* trans, const EntryKernelSet& entries); 79 80 // Return true if delete journals of |type| are maintained. 81 static bool IsDeleteJournalEnabled(ModelType type); 82 83 private: 84 // Contains deleted entries that may not be persisted in native models. And 85 // in case of unrecoverable error, all purged entries are moved here for 86 // bookkeeping to prevent back-from-dead entries that are deleted elsewhere 87 // when sync's down. 88 JournalIndex delete_journals_; 89 90 // Contains meta handles of deleted entries that have been persisted or 91 // undeleted, thus can be removed from database. 92 MetahandleSet delete_journals_to_purge_; 93 94 // Delete journals of these types can be cleared from memory after being 95 // saved to database. 96 ModelTypeSet passive_delete_journal_types_; 97 98 DISALLOW_COPY_AND_ASSIGN(DeleteJournal); 99 }; 100 101 } // namespace syncable 102 } // namespace syncer 103 104 #endif // SYNC_SYNCABLE_SYNCABLE_DELETE_JOURNAL_H_ 105