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Diffstat (limited to 'chrome/browser/history/history_database.h')
| -rw-r--r-- | chrome/browser/history/history_database.h | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/chrome/browser/history/history_database.h b/chrome/browser/history/history_database.h new file mode 100644 index 0000000..3b3414a --- /dev/null +++ b/chrome/browser/history/history_database.h @@ -0,0 +1,188 @@ +// Copyright (c) 2009 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 CHROME_BROWSER_HISTORY_HISTORY_DATABASE_H_ +#define CHROME_BROWSER_HISTORY_HISTORY_DATABASE_H_ + +#include "app/sql/connection.h" +#include "app/sql/init_status.h" +#include "app/sql/meta_table.h" +#include "build/build_config.h" +#include "chrome/browser/history/download_database.h" +#include "chrome/browser/history/history_types.h" +#include "chrome/browser/history/starred_url_database.h" +#include "chrome/browser/history/url_database.h" +#include "chrome/browser/history/visit_database.h" +#include "chrome/browser/history/visitsegment_database.h" + +class FilePath; + +namespace history { + +// Forward declaration for the temporary migration code in Init(). +class TextDatabaseManager; + +// Encapsulates the SQL connection for the history database. This class holds +// the database connection and has methods the history system (including full +// text search) uses for writing and retrieving information. +// +// We try to keep most logic out of the history database; this should be seen +// as the storage interface. Logic for manipulating this storage layer should +// be in HistoryBackend.cc. +class HistoryDatabase : public DownloadDatabase, + // TODO(sky): See if we can nuke StarredURLDatabase and just create on the + // stack for migration. Then HistoryDatabase would directly descend from + // URLDatabase. + public StarredURLDatabase, + public VisitDatabase, + public VisitSegmentDatabase { + public: + // A simple class for scoping a history database transaction. This does not + // support rollback since the history database doesn't, either. + class TransactionScoper { + public: + explicit TransactionScoper(HistoryDatabase* db) : db_(db) { + db_->BeginTransaction(); + } + ~TransactionScoper() { + db_->CommitTransaction(); + } + private: + HistoryDatabase* db_; + }; + + // Must call Init() to complete construction. Although it can be created on + // any thread, it must be destructed on the history thread for proper + // database cleanup. + HistoryDatabase(); + + virtual ~HistoryDatabase(); + + // Must call this function to complete initialization. Will return true on + // success. On false, no other function should be called. You may want to call + // BeginExclusiveMode after this when you are ready. + sql::InitStatus Init(const FilePath& history_name, + const FilePath& tmp_bookmarks_path); + + // Call to set the mode on the database to exclusive. The default locking mode + // is "normal" but we want to run in exclusive mode for slightly better + // performance since we know nobody else is using the database. This is + // separate from Init() since the in-memory database attaches to slurp the + // data out, and this can't happen in exclusive mode. + void BeginExclusiveMode(); + + // Returns the current version that we will generate history databases with. + static int GetCurrentVersion(); + + // Transactions on the history database. Use the Transaction object above + // for most work instead of these directly. We support nested transactions + // and only commit when the outermost transaction is committed. This means + // that it is impossible to rollback a specific transaction. We could roll + // back the outermost transaction if any inner one is rolled back, but it + // turns out we don't really need this type of integrity for the history + // database, so we just don't support it. + void BeginTransaction(); + void CommitTransaction(); + int transaction_nesting() const { // for debugging and assertion purposes + return db_.transaction_nesting(); + } + + // Drops all tables except the URL, and download tables, and recreates them + // from scratch. This is done to rapidly clean up stuff when deleting all + // history. It is faster and less likely to have problems that deleting all + // rows in the tables. + // + // We don't delete the downloads table, since there may be in progress + // downloads. We handle the download history clean up separately in: + // DownloadManager::RemoveDownloadsFromHistoryBetween. + // + // Returns true on success. On failure, the caller should assume that the + // database is invalid. There could have been an error recreating a table. + // This should be treated the same as an init failure, and the database + // should not be used any more. + // + // This will also recreate the supplementary URL indices, since these + // indices won't be created automatically when using the temporary URL + // table (what the caller does right before calling this). + bool RecreateAllTablesButURL(); + + // Vacuums the database. This will cause sqlite to defragment and collect + // unused space in the file. It can be VERY SLOW. + void Vacuum(); + + // Returns true if the history backend should erase the full text search + // and archived history files as part of version 16 -> 17 migration. The + // time format changed in this revision, and these files would be much slower + // to migrate. Since the data is less important, they should be deleted. + // + // This flag will be valid after Init() is called. It will always be false + // when running on Windows. + bool needs_version_17_migration() const { + return needs_version_17_migration_; + } + + // Returns true if the Thumbnails database should be renamed to + // Favicons database. 17 -> 18 is migration to TopSites. ThumbnailsDatabase + // doesn't store the thumbnails any more, only the favicons. Hence, its file + // is renamed from Thumbnails to Favicons. + bool needs_version_18_migration() const { + return needs_version_18_migration_; + } + + // Update the database version after the TopSites migration. + void MigrationToTopSitesDone(); + + // Visit table functions ---------------------------------------------------- + + // Update the segment id of a visit. Return true on success. + bool SetSegmentID(VisitID visit_id, SegmentID segment_id); + + // Query the segment ID for the provided visit. Return 0 on failure or if the + // visit id wasn't found. + SegmentID GetSegmentID(VisitID visit_id); + + // Retrieves/Updates early expiration threshold, which specifies the earliest + // known point in history that may possibly to contain visits suitable for + // early expiration (AUTO_SUBFRAMES). + virtual base::Time GetEarlyExpirationThreshold(); + virtual void UpdateEarlyExpirationThreshold(base::Time threshold); + + private: + // Implemented for URLDatabase. + virtual sql::Connection& GetDB(); + + // Migration ----------------------------------------------------------------- + + // Makes sure the version is up-to-date, updating if necessary. If the + // database is too old to migrate, the user will be notified. In this case, or + // for other errors, false will be returned. True means it is up-to-date and + // ready for use. + // + // This assumes it is called from the init function inside a transaction. It + // may commit the transaction and start a new one if migration requires it. + sql::InitStatus EnsureCurrentVersion(const FilePath& tmp_bookmarks_path); + +#if !defined(OS_WIN) + // Converts the time epoch in the database from being 1970-based to being + // 1601-based which corresponds to the change in Time.internal_value_. + void MigrateTimeEpoch(); +#endif + + // --------------------------------------------------------------------------- + + sql::Connection db_; + sql::MetaTable meta_table_; + + base::Time cached_early_expiration_threshold_; + + // See the getters above. + bool needs_version_17_migration_; + bool needs_version_18_migration_; + + DISALLOW_COPY_AND_ASSIGN(HistoryDatabase); +}; + +} // history + +#endif // CHROME_BROWSER_HISTORY_HISTORY_DATABASE_H_ |