components/history/core/browser/history_database.h - chromium/src - Git at Google

 // Copyright (c) 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 COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_DATABASE_H_
 #define COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_DATABASE_H_

 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/raw_ptr.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "components/history/core/browser/download_database.h"
 #include "components/history/core/browser/history_types.h"
 #include "components/history/core/browser/sync/typed_url_sync_metadata_database.h"
 #include "components/history/core/browser/url_database.h"
 #include "components/history/core/browser/visit_annotations_database.h"
 #include "components/history/core/browser/visit_database.h"
 #include "components/history/core/browser/visitsegment_database.h"
 #include "sql/database.h"
 #include "sql/init_status.h"
 #include "sql/meta_table.h"

 #if BUILDFLAG(IS_ANDROID)
 #include "components/history/core/browser/android/android_cache_database.h"
 #include "components/history/core/browser/android/android_urls_database.h"
 #endif

 namespace base {
 class FilePath;
 }

 class InMemoryURLIndexTest;

 namespace history {

 // 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,
 #if BUILDFLAG(IS_ANDROID)
                         public AndroidURLsDatabase,
                         public AndroidCacheDatabase,
 #endif
                         public TypedURLSyncMetadataDatabase,
                         public URLDatabase,
                         public VisitDatabase,
                         public VisitAnnotationsDatabase,
                         public VisitSegmentDatabase {
  public:
   // 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(DownloadInterruptReason download_interrupt_reason_none,
                   DownloadInterruptReason download_interrupt_reason_crash);

   HistoryDatabase(const HistoryDatabase&) = delete;
   HistoryDatabase& operator=(const HistoryDatabase&) = delete;

   ~HistoryDatabase() override;

   // Call before Init() to set the error callback to be used for the
   // underlying database connection.
   void set_error_callback(const sql::Database::ErrorCallback& error_callback) {
     db_.set_error_callback(error_callback);
   }
   void reset_error_callback() { db_.reset_error_callback(); }

   // Must call this function to complete initialization. Will return
   // sql::INIT_OK on success. Otherwise, no other function should be called. You
   // may want to call BeginExclusiveMode after this when you are ready.
   sql::InitStatus Init(const base::FilePath& history_name);

   // Computes and records various metrics for the database. Should only be
   // called once and only upon successful Init.
   void ComputeDatabaseMetrics(const base::FilePath& filename);

   // Counts the number of unique Hosts visited in the last month.
   int CountUniqueHostsVisitedLastMonth();

   // Counts the number of unique domains (eLTD+1) visited within
   // [`begin_time`, `end_time`).
   int CountUniqueDomainsVisited(base::Time begin_time, base::Time end_time);

   // 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();
   }
   void RollbackTransaction();

   // 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:
   // content::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();

   // Release all non-essential memory associated with this database connection.
   void TrimMemory();

   // Razes the database. Returns true if successful.
   bool Raze();

   std::string GetDiagnosticInfo(int extended_error, sql::Statement* statement);

   // 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:
 #if BUILDFLAG(IS_ANDROID)
   // AndroidProviderBackend uses the `db_`.
   friend class AndroidProviderBackend;
   FRIEND_TEST_ALL_PREFIXES(AndroidURLsMigrationTest, MigrateToVersion22);
 #endif
   friend class ::InMemoryURLIndexTest;

   // Overridden from URLDatabase, DownloadDatabase, VisitDatabase,
   // VisitSegmentDatabase and TypedURLSyncMetadataDatabase.
   sql::Database& GetDB() override;

   // Overridden from TypedURLSyncMetadataDatabase.
   sql::MetaTable& GetMetaTable() override;

   // 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. Returns
   // sql::INIT_OK iff the DB 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();

 #if !BUILDFLAG(IS_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::Database db_;
   sql::MetaTable meta_table_;

   base::Time cached_early_expiration_threshold_;
 };

 }  // namespace history

 #endif  // COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_DATABASE_H_
	// Copyright (c) 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 COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_DATABASE_H_
	#define COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_DATABASE_H_

	#include "base/compiler_specific.h"
	#include "base/gtest_prod_util.h"
	#include "base/memory/raw_ptr.h"
	#include "base/time/time.h"
	#include "build/build_config.h"
	#include "components/history/core/browser/download_database.h"
	#include "components/history/core/browser/history_types.h"
	#include "components/history/core/browser/sync/typed_url_sync_metadata_database.h"
	#include "components/history/core/browser/url_database.h"
	#include "components/history/core/browser/visit_annotations_database.h"
	#include "components/history/core/browser/visit_database.h"
	#include "components/history/core/browser/visitsegment_database.h"
	#include "sql/database.h"
	#include "sql/init_status.h"
	#include "sql/meta_table.h"

	#if BUILDFLAG(IS_ANDROID)
	#include "components/history/core/browser/android/android_cache_database.h"
	#include "components/history/core/browser/android/android_urls_database.h"
	#endif

	namespace base {
	class FilePath;
	}

	class InMemoryURLIndexTest;

	namespace history {

	// 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,
	#if BUILDFLAG(IS_ANDROID)
	public AndroidURLsDatabase,
	public AndroidCacheDatabase,
	#endif
	public TypedURLSyncMetadataDatabase,
	public URLDatabase,
	public VisitDatabase,
	public VisitAnnotationsDatabase,
	public VisitSegmentDatabase {
	public:
	// 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(DownloadInterruptReason download_interrupt_reason_none,
	DownloadInterruptReason download_interrupt_reason_crash);

	HistoryDatabase(const HistoryDatabase&) = delete;
	HistoryDatabase& operator=(const HistoryDatabase&) = delete;

	~HistoryDatabase() override;

	// Call before Init() to set the error callback to be used for the
	// underlying database connection.
	void set_error_callback(const sql::Database::ErrorCallback& error_callback) {
	db_.set_error_callback(error_callback);
	}
	void reset_error_callback() { db_.reset_error_callback(); }

	// Must call this function to complete initialization. Will return
	// sql::INIT_OK on success. Otherwise, no other function should be called. You
	// may want to call BeginExclusiveMode after this when you are ready.
	sql::InitStatus Init(const base::FilePath& history_name);

	// Computes and records various metrics for the database. Should only be
	// called once and only upon successful Init.
	void ComputeDatabaseMetrics(const base::FilePath& filename);

	// Counts the number of unique Hosts visited in the last month.
	int CountUniqueHostsVisitedLastMonth();

	// Counts the number of unique domains (eLTD+1) visited within
	// [`begin_time`, `end_time`).
	int CountUniqueDomainsVisited(base::Time begin_time, base::Time end_time);

	// 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();
	}
	void RollbackTransaction();

	// 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:
	// content::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();

	// Release all non-essential memory associated with this database connection.
	void TrimMemory();

	// Razes the database. Returns true if successful.
	bool Raze();

	std::string GetDiagnosticInfo(int extended_error, sql::Statement* statement);

	// 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:
	#if BUILDFLAG(IS_ANDROID)
	// AndroidProviderBackend uses the `db_`.
	friend class AndroidProviderBackend;
	FRIEND_TEST_ALL_PREFIXES(AndroidURLsMigrationTest, MigrateToVersion22);
	#endif
	friend class ::InMemoryURLIndexTest;

	// Overridden from URLDatabase, DownloadDatabase, VisitDatabase,
	// VisitSegmentDatabase and TypedURLSyncMetadataDatabase.
	sql::Database& GetDB() override;

	// Overridden from TypedURLSyncMetadataDatabase.
	sql::MetaTable& GetMetaTable() override;

	// 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. Returns
	// sql::INIT_OK iff the DB 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();

	#if !BUILDFLAG(IS_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::Database db_;
	sql::MetaTable meta_table_;

	base::Time cached_early_expiration_threshold_;
	};

	} // namespace history

	#endif // COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_DATABASE_H_