[Sync] Move //sync to //components/sync.

sync/syncable/directory_backing_store.h

Index: sync/syncable/directory_backing_store.h
diff --git a/sync/syncable/directory_backing_store.h b/sync/syncable/directory_backing_store.h
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index a2c8d9cc80bcfa7d92f13cf9e24ec92572173b2a..0000000000000000000000000000000000000000
--- a/sync/syncable/directory_backing_store.h
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-// Copyright 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.
-
-#ifndef SYNC_SYNCABLE_DIRECTORY_BACKING_STORE_H_
-#define SYNC_SYNCABLE_DIRECTORY_BACKING_STORE_H_
-
-#include <stdint.h>
-
-#include <memory>
-#include <string>
-
-#include "base/gtest_prod_util.h"
-#include "base/macros.h"
-#include "base/threading/non_thread_safe.h"
-#include "sql/connection.h"
-#include "sql/statement.h"
-#include "sync/base/sync_export.h"
-#include "sync/internal_api/public/base/model_type.h"
-#include "sync/syncable/dir_open_result.h"
-#include "sync/syncable/directory.h"
-#include "sync/syncable/metahandle_set.h"
-
-namespace sync_pb {
-class EntitySpecifics;
-}
-
-namespace syncer {
-namespace syncable {
-
-SYNC_EXPORT extern const int32_t kCurrentDBVersion;
-SYNC_EXPORT extern const int32_t kCurrentPageSizeKB;
-
-struct ColumnSpec;
-
-// Interface that provides persistence for a syncable::Directory object. You can
-// load all the persisted data to prime a syncable::Directory on startup by
-// invoking Load.  The only other thing you (or more correctly, a Directory) can
-// do here is save any changes that have occurred since calling Load, which can
-// be done periodically as often as desired.
-//
-// The DirectoryBackingStore will own an sqlite lock on its database for most of
-// its lifetime.  You must not have two DirectoryBackingStore objects accessing
-// the database simultaneously.  Because the lock exists at the database level,
-// not even two separate browser instances would be able to acquire it
-// simultaneously.
-//
-// This class is abstract so that we can extend it in interesting ways for use
-// in tests.  The concrete class used in non-test scenarios is
-// OnDiskDirectoryBackingStore.
-class SYNC_EXPORT DirectoryBackingStore : public base::NonThreadSafe {
- public:
-  explicit DirectoryBackingStore(const std::string& dir_name);
-  virtual ~DirectoryBackingStore();
-
-  // Loads and drops all currently persisted meta entries into |handles_map|
-  // and loads appropriate persisted kernel info into |kernel_load_info|.
-  // The function determines which entries can be safely dropped and inserts
-  // their keys into |metahandles_to_purge|. It is up to the caller to
-  // perform the actual cleanup.
-  //
-  // This function will migrate to the latest database version.
-  //
-  // NOTE: On success (return value of OPENED), the buckets are populated with
-  // newly allocated items, meaning ownership is bestowed upon the caller.
-  virtual DirOpenResult Load(Directory::MetahandlesMap* handles_map,
-                             JournalIndex* delete_journals,
-                             MetahandleSet* metahandles_to_purge,
-                             Directory::KernelLoadInfo* kernel_load_info) = 0;
-
-  // Updates the on-disk store with the input |snapshot| as a database
-  // transaction.  Does NOT open any syncable transactions as this would cause
-  // opening transactions elsewhere to block on synchronous I/O.
-  // DO NOT CALL THIS FROM MORE THAN ONE THREAD EVER.  Also, whichever thread
-  // calls SaveChanges *must* be the thread that owns/destroys |this|.
-  //
-  // Returns true if the changes were saved successfully. Returns false if an
-  // error (of any kind) occurred. See also |SetCatastrophicErrorHandler| for a
-  // systematic way of handling underlying DB errors.
-  virtual bool SaveChanges(const Directory::SaveChangesSnapshot& snapshot);
-
-  // Set the catastrophic error handler.
-  //
-  // When a catastrophic error is encountered while accessing the underlying DB,
-  // |catastrophic_error_handler| will be invoked (via PostTask) on the thread
-  // on which this DirectoryBackingStore object lives.
-  //
-  // For a definition of what's catastrophic, see sql::IsErrorCatastrophic.
-  //
-  // |catastrophic_error_handler| must be initialized (i.e. !is_null()).
-  //
-  // A single operation (like Load or SaveChanges) may result in the
-  // |catastrophic_error_handler| being invoked several times.
-  //
-  // There can be at most one handler. If this method is invoked when there is
-  // already a handler, the existing handler is overwritten with
-  // |catastrophic_error_handler|.
-  virtual void SetCatastrophicErrorHandler(
-      const base::Closure& catastrophic_error_handler);
-
-  // Returns true on success, false on error.
-  bool GetDatabasePageSize(int* page_size);
-
- protected:
-  // For test classes.
-  DirectoryBackingStore(const std::string& dir_name,
-                        sql::Connection* connection);
-
-  // An accessor for the underlying sql::Connection. Avoid using outside of
-  // tests.
-  sql::Connection* db();
-
-  // Return true if the DB is open.
-  bool IsOpen() const;
-
-  // Open the DB at |path|.
-  // Return true on success, false on failure.
-  bool Open(const base::FilePath& path);
-
-  // Open an in memory DB.
-  // Return true on success, false on failure.
-  bool OpenInMemory();
-
-  // Initialize database tables. Return true on success, false on error.
-  bool InitializeTables();
-
-  // Load helpers for entries and attributes. Return true on success, false on
-  // error.
-  bool LoadEntries(Directory::MetahandlesMap* handles_map,
-                   MetahandleSet* metahandles_to_purge);
-  bool LoadDeleteJournals(JournalIndex* delete_journals);
-  bool LoadInfo(Directory::KernelLoadInfo* info);
-
-  enum EntryTable {
-    METAS_TABLE,
-    DELETE_JOURNAL_TABLE,
-  };
-  // Removes each entry whose metahandle is in |handles| from the table
-  // specified by |from| table. Does synchronous I/O.  Returns false on error.
-  bool DeleteEntries(EntryTable from, const MetahandleSet& handles);
-
-  // Serialization helpers for ModelType.  These convert between
-  // the ModelType enum and the values we persist in the database to identify
-  // a model.  We persist a default instance of the specifics protobuf as the
-  // ID, rather than the enum value.
-  static ModelType ModelIdToModelTypeEnum(const void* data, int length);
-  static std::string ModelTypeEnumToModelId(ModelType model_type);
-
-  static std::string GenerateCacheGUID();
-
-  // Checks that the references between sync nodes is consistent.
-  static bool VerifyReferenceIntegrity(
-      const Directory::MetahandlesMap* handles_map);
-
-  // Migration utilities.
-  bool RefreshColumns();
-  bool SetVersion(int version);
-  int GetVersion();
-
-  // Individual version migrations.
-  bool MigrateVersion67To68();
-  bool MigrateVersion68To69();
-  bool MigrateVersion69To70();
-  bool MigrateVersion70To71();
-  bool MigrateVersion71To72();
-  bool MigrateVersion72To73();
-  bool MigrateVersion73To74();
-  bool MigrateVersion74To75();
-  bool MigrateVersion75To76();
-  bool MigrateVersion76To77();
-  bool MigrateVersion77To78();
-  bool MigrateVersion78To79();
-  bool MigrateVersion79To80();
-  bool MigrateVersion80To81();
-  bool MigrateVersion81To82();
-  bool MigrateVersion82To83();
-  bool MigrateVersion83To84();
-  bool MigrateVersion84To85();
-  bool MigrateVersion85To86();
-  bool MigrateVersion86To87();
-  bool MigrateVersion87To88();
-  bool MigrateVersion88To89();
-  bool MigrateVersion89To90();
-
-  // Accessor for needs_column_refresh_.  Used in tests.
-  bool needs_column_refresh() const;
-
-  // Destroys the existing Connection and creates a new one.
-  void ResetAndCreateConnection();
-
- private:
-  friend class DirectoryBackingStoreTest;
-  friend class TestDirectoryBackingStore;
-  FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest,
-                           IncreaseDatabasePageSizeFrom4KTo32K);
-  FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest,
-                           CatastrophicErrorHandler_KeptAcrossReset);
-  FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest,
-                           CatastrophicErrorHandler_InvocationDuringLoad);
-  FRIEND_TEST_ALL_PREFIXES(
-      DirectoryBackingStoreTest,
-      CatastrophicErrorHandler_InvocationDuringSaveChanges);
-  FRIEND_TEST_ALL_PREFIXES(MigrationTest, ToCurrentVersion);
-
-  // Drop all tables in preparation for reinitialization.
-  void DropAllTables();
-
-  bool SafeToPurgeOnLoading(const EntryKernel& entry) const;
-
-  // Drops a table if it exists, harmless if the table did not already exist.
-  bool SafeDropTable(const char* table_name);
-
-  bool CreateTables();
-
-  // Create 'share_info' or 'temp_share_info' depending on value of
-  // is_temporary. Returns true on success, false on error.
-  bool CreateShareInfoTable(bool is_temporary);
-  bool CreateShareInfoTableVersion71(bool is_temporary);
-
-  // Create 'metas' or 'temp_metas' depending on value of is_temporary. Also
-  // create a 'deleted_metas' table using same schema. Returns true on success,
-  // false on error.
-  bool CreateMetasTable(bool is_temporary);
-
-  // Returns true on success, false on error.
-  bool CreateModelsTable();
-  bool CreateV71ModelsTable();
-  bool CreateV75ModelsTable();
-  bool CreateV81ModelsTable();
-
-  // Returns true on success, false on error.
-  bool MigrateToSpecifics(const char* old_columns,
-                          const char* specifics_column,
-                          void(*handler_function) (
-                              sql::Statement* old_value_query,
-                              int old_value_column,
-                              sync_pb::EntitySpecifics* mutable_new_value));
-
-  // Returns true on success, false on error.
-  bool Vacuum();
-
-  // Returns true on success, false on error.
-  bool UpdatePageSizeIfNecessary();
-
-  // Prepares |save_statement| for saving entries in |table|.
-  void PrepareSaveEntryStatement(EntryTable table,
-                                 sql::Statement* save_statement);
-
-  const std::string dir_name_;
-  const int database_page_size_;
-
-  std::unique_ptr<sql::Connection> db_;
-  sql::Statement save_meta_statement_;
-  sql::Statement save_delete_journal_statement_;
-
-  // Set to true if migration left some old columns around that need to be
-  // discarded.
-  bool needs_metas_column_refresh_;
-  bool needs_share_info_column_refresh_;
-
-  // We keep a copy of the Closure so we reinstall it when the underlying
-  // sql::Connection is destroyed/recreated.
-  base::Closure catastrophic_error_handler_;
-
-  DISALLOW_COPY_AND_ASSIGN(DirectoryBackingStore);
-};
-
-}  // namespace syncable
-}  // namespace syncer
-
-#endif  // SYNC_SYNCABLE_DIRECTORY_BACKING_STORE_H_