third_party/WebKit/Source/modules/webdatabase/Database.cpp

/*
 * Copyright (C) 2013 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "modules/webdatabase/Database.h"

#include "core/dom/ExceptionCode.h"
#include "core/dom/ExecutionContext.h"
#include "core/dom/ExecutionContextTask.h"
#include "core/dom/TaskRunnerHelper.h"
#include "core/html/VoidCallback.h"
#include "core/inspector/ConsoleMessage.h"
#include "modules/webdatabase/ChangeVersionData.h"
#include "modules/webdatabase/ChangeVersionWrapper.h"
#include "modules/webdatabase/DatabaseAuthorizer.h"
#include "modules/webdatabase/DatabaseContext.h"
#include "modules/webdatabase/DatabaseManager.h"
#include "modules/webdatabase/DatabaseTask.h"
#include "modules/webdatabase/DatabaseThread.h"
#include "modules/webdatabase/DatabaseTracker.h"
#include "modules/webdatabase/SQLError.h"
#include "modules/webdatabase/SQLTransaction.h"
#include "modules/webdatabase/SQLTransactionBackend.h"
#include "modules/webdatabase/SQLTransactionCallback.h"
#include "modules/webdatabase/SQLTransactionClient.h"
#include "modules/webdatabase/SQLTransactionCoordinator.h"
#include "modules/webdatabase/SQLTransactionErrorCallback.h"
#include "modules/webdatabase/StorageLog.h"
#include "modules/webdatabase/sqlite/SQLiteStatement.h"
#include "modules/webdatabase/sqlite/SQLiteTransaction.h"
#include "platform/WaitableEvent.h"
#include "platform/heap/SafePoint.h"
#include "public/platform/Platform.h"
#include "public/platform/WebDatabaseObserver.h"
#include "public/platform/WebSecurityOrigin.h"
#include "wtf/Atomics.h"
#include "wtf/CurrentTime.h"
#include <memory>

// Registering "opened" databases with the DatabaseTracker
// =======================================================
// The DatabaseTracker maintains a list of databases that have been
// "opened" so that the client can call interrupt or delete on every database
// associated with a DatabaseContext.
//
// We will only call DatabaseTracker::addOpenDatabase() to add the database
// to the tracker as opened when we've succeeded in opening the database,
// and will set m_opened to true. Similarly, we only call
// DatabaseTracker::removeOpenDatabase() to remove the database from the
// tracker when we set m_opened to false in closeDatabase(). This sets up
// a simple symmetry between open and close operations, and a direct
// correlation to adding and removing databases from the tracker's list,
// thus ensuring that we have a correct list for the interrupt and
// delete operations to work on.
//
// The only databases instances not tracked by the tracker's open database
// list are the ones that have not been added yet, or the ones that we
// attempted an open on but failed to. Such instances only exist in the
// DatabaseServer's factory methods for creating database backends.
//
// The factory methods will either call openAndVerifyVersion() or
// performOpenAndVerify(). These methods will add the newly instantiated
// database backend if they succeed in opening the requested database.
// In the case of failure to open the database, the factory methods will
// simply discard the newly instantiated database backend when they return.
// The ref counting mechanims will automatically destruct the un-added
// (and un-returned) databases instances.

namespace blink {

// Defines static local variable after making sure that guid lock is held.
// (We can't use DEFINE_STATIC_LOCAL for this because it asserts thread
// safety, which is externally guaranteed by the guideMutex lock)
#define DEFINE_STATIC_LOCAL_WITH_LOCK(type, name, arguments) \
  ASSERT(guidMutex().locked());                              \
  static type& name = *new type arguments

static const char versionKey[] = "WebKitDatabaseVersionKey";
static const char infoTableName[] = "__WebKitDatabaseInfoTable__";

static String formatErrorMessage(const char* message,
                                 int sqliteErrorCode,
                                 const char* sqliteErrorMessage) {
  return String::format("%s (%d %s)", message, sqliteErrorCode,
                        sqliteErrorMessage);
}

static bool retrieveTextResultFromDatabase(SQLiteDatabase& db,
                                           const String& query,
                                           String& resultString) {
  SQLiteStatement statement(db, query);
  int result = statement.prepare();

  if (result != SQLResultOk) {
    DLOG(ERROR) << "Error (" << result
                << ") preparing statement to read text result from database ("
                << query << ")";
    return false;
  }

  result = statement.step();
  if (result == SQLResultRow) {
    resultString = statement.getColumnText(0);
    return true;
  }
  if (result == SQLResultDone) {
    resultString = String();
    return true;
  }

  DLOG(ERROR) << "Error (" << result << ") reading text result from database ("
              << query << ")";
  return false;
}

static bool setTextValueInDatabase(SQLiteDatabase& db,
                                   const String& query,
                                   const String& value) {
  SQLiteStatement statement(db, query);
  int result = statement.prepare();

  if (result != SQLResultOk) {
    DLOG(ERROR) << "Failed to prepare statement to set value in database ("
                << query << ")";
    return false;
  }

  statement.bindText(1, value);

  result = statement.step();
  if (result != SQLResultDone) {
    DLOG(ERROR) << "Failed to step statement to set value in database ("
                << query << ")";
    return false;
  }

  return true;
}

// FIXME: move all guid-related functions to a DatabaseVersionTracker class.
static RecursiveMutex& guidMutex() {
  DEFINE_THREAD_SAFE_STATIC_LOCAL(RecursiveMutex, mutex, new RecursiveMutex);
  return mutex;
}

typedef HashMap<DatabaseGuid, String> GuidVersionMap;
static GuidVersionMap& guidToVersionMap() {
  DEFINE_STATIC_LOCAL_WITH_LOCK(GuidVersionMap, map, ());
  return map;
}

// NOTE: Caller must lock guidMutex().
static inline void updateGuidVersionMap(DatabaseGuid guid, String newVersion) {
  // Ensure the the mutex is locked.
  ASSERT(guidMutex().locked());

  // Note: It is not safe to put an empty string into the guidToVersionMap()
  // map. That's because the map is cross-thread, but empty strings are
  // per-thread. The copy() function makes a version of the string you can
  // use on the current thread, but we need a string we can keep in a
  // cross-thread data structure.
  // FIXME: This is a quite-awkward restriction to have to program with.

  // Map null string to empty string (see comment above).
  guidToVersionMap().set(
      guid, newVersion.isEmpty() ? String() : newVersion.isolatedCopy());
}

static HashCountedSet<DatabaseGuid>& guidCount() {
  DEFINE_STATIC_LOCAL_WITH_LOCK(HashCountedSet<DatabaseGuid>, guidCount, ());
  return guidCount;
}

static DatabaseGuid guidForOriginAndName(const String& origin,
                                         const String& name) {
  // Ensure the the mutex is locked.
  ASSERT(guidMutex().locked());

  String stringID = origin + "/" + name;

  typedef HashMap<String, int> IDGuidMap;
  DEFINE_STATIC_LOCAL_WITH_LOCK(IDGuidMap, stringIdentifierToGUIDMap, ());
  DatabaseGuid guid = stringIdentifierToGUIDMap.get(stringID);
  if (!guid) {
    static int currentNewGUID = 1;
    guid = currentNewGUID++;
    stringIdentifierToGUIDMap.set(stringID, guid);
  }

  return guid;
}

Database::Database(DatabaseContext* databaseContext,
                   const String& name,
                   const String& expectedVersion,
                   const String& displayName,
                   unsigned estimatedSize)
    : m_databaseContext(databaseContext),
      m_name(name.isolatedCopy()),
      m_expectedVersion(expectedVersion.isolatedCopy()),
      m_displayName(displayName.isolatedCopy()),
      m_estimatedSize(estimatedSize),
      m_guid(0),
      m_opened(0),
      m_new(false),
      m_transactionInProgress(false),
      m_isTransactionQueueEnabled(true) {
  DCHECK(isMainThread());
  m_contextThreadSecurityOrigin =
      m_databaseContext->getSecurityOrigin()->isolatedCopy();

  m_databaseAuthorizer = DatabaseAuthorizer::create(infoTableName);

  if (m_name.isNull())
    m_name = "";

  {
    SafePointAwareMutexLocker locker(guidMutex());
    m_guid = guidForOriginAndName(getSecurityOrigin()->toString(), name);
    guidCount().add(m_guid);
  }

  m_filename = DatabaseManager::manager().fullPathForDatabase(
      getSecurityOrigin(), m_name);

  m_databaseThreadSecurityOrigin =
      m_contextThreadSecurityOrigin->isolatedCopy();
  ASSERT(m_databaseContext->databaseThread());
  ASSERT(m_databaseContext->isContextThread());
}

Database::~Database() {
  // SQLite is "multi-thread safe", but each database handle can only be used
  // on a single thread at a time.
  //
  // For Database, we open the SQLite database on the DatabaseThread, and
  // hence we should also close it on that same thread. This means that the
  // SQLite database need to be closed by another mechanism (see
  // DatabaseContext::stopDatabases()). By the time we get here, the SQLite
  // database should have already been closed.

  ASSERT(!m_opened);
}

DEFINE_TRACE(Database) {
  visitor->trace(m_databaseContext);
  visitor->trace(m_sqliteDatabase);
  visitor->trace(m_databaseAuthorizer);
}

bool Database::openAndVerifyVersion(bool setVersionInNewDatabase,
                                    DatabaseError& error,
                                    String& errorMessage) {
  WaitableEvent event;
  if (!getDatabaseContext()->databaseThreadAvailable())
    return false;

  DatabaseTracker::tracker().prepareToOpenDatabase(this);
  bool success = false;
  std::unique_ptr<DatabaseOpenTask> task = DatabaseOpenTask::create(
      this, setVersionInNewDatabase, &event, error, errorMessage, success);
  getDatabaseContext()->databaseThread()->scheduleTask(std::move(task));
  event.wait();

  return success;
}

void Database::close() {
  ASSERT(getDatabaseContext()->databaseThread());
  ASSERT(getDatabaseContext()->databaseThread()->isDatabaseThread());

  {
    MutexLocker locker(m_transactionInProgressMutex);

    // Clean up transactions that have not been scheduled yet:
    // Transaction phase 1 cleanup. See comment on "What happens if a
    // transaction is interrupted?" at the top of SQLTransactionBackend.cpp.
    SQLTransactionBackend* transaction = nullptr;
    while (!m_transactionQueue.isEmpty()) {
      transaction = m_transactionQueue.takeFirst();
      transaction->notifyDatabaseThreadIsShuttingDown();
    }

    m_isTransactionQueueEnabled = false;
    m_transactionInProgress = false;
  }

  closeDatabase();
  getDatabaseContext()->databaseThread()->recordDatabaseClosed(this);
}

SQLTransactionBackend* Database::runTransaction(SQLTransaction* transaction,
                                                bool readOnly,
                                                const ChangeVersionData* data) {
  MutexLocker locker(m_transactionInProgressMutex);
  if (!m_isTransactionQueueEnabled)
    return nullptr;

  SQLTransactionWrapper* wrapper = nullptr;
  if (data)
    wrapper =
        ChangeVersionWrapper::create(data->oldVersion(), data->newVersion());

  SQLTransactionBackend* transactionBackend =
      SQLTransactionBackend::create(this, transaction, wrapper, readOnly);
  m_transactionQueue.append(transactionBackend);
  if (!m_transactionInProgress)
    scheduleTransaction();

  return transactionBackend;
}

void Database::inProgressTransactionCompleted() {
  MutexLocker locker(m_transactionInProgressMutex);
  m_transactionInProgress = false;
  scheduleTransaction();
}

void Database::scheduleTransaction() {
  ASSERT(!m_transactionInProgressMutex.tryLock());  // Locked by caller.
  SQLTransactionBackend* transaction = nullptr;

  if (m_isTransactionQueueEnabled && !m_transactionQueue.isEmpty())
    transaction = m_transactionQueue.takeFirst();

  if (transaction && getDatabaseContext()->databaseThreadAvailable()) {
    std::unique_ptr<DatabaseTransactionTask> task =
        DatabaseTransactionTask::create(transaction);
    STORAGE_DVLOG(1) << "Scheduling DatabaseTransactionTask " << task.get()
                     << " for transaction " << task->transaction();
    m_transactionInProgress = true;
    getDatabaseContext()->databaseThread()->scheduleTask(std::move(task));
  } else {
    m_transactionInProgress = false;
  }
}

void Database::scheduleTransactionStep(SQLTransactionBackend* transaction) {
  if (!getDatabaseContext()->databaseThreadAvailable())
    return;

  std::unique_ptr<DatabaseTransactionTask> task =
      DatabaseTransactionTask::create(transaction);
  STORAGE_DVLOG(1) << "Scheduling DatabaseTransactionTask " << task.get()
                   << " for the transaction step";
  getDatabaseContext()->databaseThread()->scheduleTask(std::move(task));
}

SQLTransactionClient* Database::transactionClient() const {
  return getDatabaseContext()->databaseThread()->transactionClient();
}

SQLTransactionCoordinator* Database::transactionCoordinator() const {
  return getDatabaseContext()->databaseThread()->transactionCoordinator();
}

// static
const char* Database::databaseInfoTableName() {
  return infoTableName;
}

void Database::closeDatabase() {
  if (!m_opened)
    return;

  releaseStore(&m_opened, 0);
  m_sqliteDatabase.close();
  // See comment at the top this file regarding calling removeOpenDatabase().
  DatabaseTracker::tracker().removeOpenDatabase(this);
  {
    SafePointAwareMutexLocker locker(guidMutex());

    ASSERT(guidCount().contains(m_guid));
    if (guidCount().remove(m_guid)) {
      guidToVersionMap().remove(m_guid);
    }
  }
}

String Database::version() const {
  // Note: In multi-process browsers the cached value may be accurate, but we
  // cannot read the actual version from the database without potentially
  // inducing a deadlock.
  // FIXME: Add an async version getter to the DatabaseAPI.
  return getCachedVersion();
}

class DoneCreatingDatabaseOnExitCaller {
  STACK_ALLOCATED();

 public:
  DoneCreatingDatabaseOnExitCaller(Database* database)
      : m_database(database), m_openSucceeded(false) {}
  ~DoneCreatingDatabaseOnExitCaller() {
    if (!m_openSucceeded)
      DatabaseTracker::tracker().failedToOpenDatabase(m_database);
  }

  void setOpenSucceeded() { m_openSucceeded = true; }

 private:
  CrossThreadPersistent<Database> m_database;
  bool m_openSucceeded;
};

bool Database::performOpenAndVerify(bool shouldSetVersionInNewDatabase,
                                    DatabaseError& error,
                                    String& errorMessage) {
  double callStartTime = WTF::monotonicallyIncreasingTime();
  DoneCreatingDatabaseOnExitCaller onExitCaller(this);
  ASSERT(errorMessage.isEmpty());
  ASSERT(error == DatabaseError::None);  // Better not have any errors already.
  // Presumed failure. We'll clear it if we succeed below.
  error = DatabaseError::InvalidDatabaseState;

  const int maxSqliteBusyWaitTime = 30000;

  if (!m_sqliteDatabase.open(m_filename)) {
    reportOpenDatabaseResult(
        1, InvalidStateError, m_sqliteDatabase.lastError(),
        WTF::monotonicallyIncreasingTime() - callStartTime);
    errorMessage = formatErrorMessage("unable to open database",
                                      m_sqliteDatabase.lastError(),
                                      m_sqliteDatabase.lastErrorMsg());
    return false;
  }
  if (!m_sqliteDatabase.turnOnIncrementalAutoVacuum())
    DLOG(ERROR) << "Unable to turn on incremental auto-vacuum ("
                << m_sqliteDatabase.lastError() << " "
                << m_sqliteDatabase.lastErrorMsg() << ")";

  m_sqliteDatabase.setBusyTimeout(maxSqliteBusyWaitTime);

  String currentVersion;
  {
    SafePointAwareMutexLocker locker(guidMutex());

    GuidVersionMap::iterator entry = guidToVersionMap().find(m_guid);
    if (entry != guidToVersionMap().end()) {
      // Map null string to empty string (see updateGuidVersionMap()).
      currentVersion =
          entry->value.isNull() ? emptyString() : entry->value.isolatedCopy();
      STORAGE_DVLOG(1) << "Current cached version for guid " << m_guid << " is "
                       << currentVersion;

      // Note: In multi-process browsers the cached value may be
      // inaccurate, but we cannot read the actual version from the
      // database without potentially inducing a form of deadlock, a
      // busytimeout error when trying to access the database. So we'll
      // use the cached value if we're unable to read the value from the
      // database file without waiting.
      // FIXME: Add an async openDatabase method to the DatabaseAPI.
      const int noSqliteBusyWaitTime = 0;
      m_sqliteDatabase.setBusyTimeout(noSqliteBusyWaitTime);
      String versionFromDatabase;
      if (getVersionFromDatabase(versionFromDatabase, false)) {
        currentVersion = versionFromDatabase;
        updateGuidVersionMap(m_guid, currentVersion);
      }
      m_sqliteDatabase.setBusyTimeout(maxSqliteBusyWaitTime);
    } else {
      STORAGE_DVLOG(1) << "No cached version for guid " << m_guid;

      SQLiteTransaction transaction(m_sqliteDatabase);
      transaction.begin();
      if (!transaction.inProgress()) {
        reportOpenDatabaseResult(
            2, InvalidStateError, m_sqliteDatabase.lastError(),
            WTF::monotonicallyIncreasingTime() - callStartTime);
        errorMessage = formatErrorMessage(
            "unable to open database, failed to start transaction",
            m_sqliteDatabase.lastError(), m_sqliteDatabase.lastErrorMsg());
        m_sqliteDatabase.close();
        return false;
      }

      String tableName(infoTableName);
      if (!m_sqliteDatabase.tableExists(tableName)) {
        m_new = true;

        if (!m_sqliteDatabase.executeCommand(
                "CREATE TABLE " + tableName +
                " (key TEXT NOT NULL ON CONFLICT FAIL UNIQUE ON CONFLICT "
                "REPLACE,value TEXT NOT NULL ON CONFLICT FAIL);")) {
          reportOpenDatabaseResult(
              3, InvalidStateError, m_sqliteDatabase.lastError(),
              WTF::monotonicallyIncreasingTime() - callStartTime);
          errorMessage = formatErrorMessage(
              "unable to open database, failed to create 'info' table",
              m_sqliteDatabase.lastError(), m_sqliteDatabase.lastErrorMsg());
          transaction.rollback();
          m_sqliteDatabase.close();
          return false;
        }
      } else if (!getVersionFromDatabase(currentVersion, false)) {
        reportOpenDatabaseResult(
            4, InvalidStateError, m_sqliteDatabase.lastError(),
            WTF::monotonicallyIncreasingTime() - callStartTime);
        errorMessage = formatErrorMessage(
            "unable to open database, failed to read current version",
            m_sqliteDatabase.lastError(), m_sqliteDatabase.lastErrorMsg());
        transaction.rollback();
        m_sqliteDatabase.close();
        return false;
      }

      if (currentVersion.length()) {
        STORAGE_DVLOG(1) << "Retrieved current version " << currentVersion
                         << " from database " << databaseDebugName();
      } else if (!m_new || shouldSetVersionInNewDatabase) {
        STORAGE_DVLOG(1) << "Setting version " << m_expectedVersion
                         << " in database " << databaseDebugName()
                         << " that was just created";
        if (!setVersionInDatabase(m_expectedVersion, false)) {
          reportOpenDatabaseResult(
              5, InvalidStateError, m_sqliteDatabase.lastError(),
              WTF::monotonicallyIncreasingTime() - callStartTime);
          errorMessage = formatErrorMessage(
              "unable to open database, failed to write current version",
              m_sqliteDatabase.lastError(), m_sqliteDatabase.lastErrorMsg());
          transaction.rollback();
          m_sqliteDatabase.close();
          return false;
        }
        currentVersion = m_expectedVersion;
      }
      updateGuidVersionMap(m_guid, currentVersion);
      transaction.commit();
    }
  }

  if (currentVersion.isNull()) {
    STORAGE_DVLOG(1) << "Database " << databaseDebugName()
                     << " does not have its version set";
    currentVersion = "";
  }

  // If the expected version isn't the empty string, ensure that the current
  // database version we have matches that version. Otherwise, set an
  // exception.
  // If the expected version is the empty string, then we always return with
  // whatever version of the database we have.
  if ((!m_new || shouldSetVersionInNewDatabase) && m_expectedVersion.length() &&
      m_expectedVersion != currentVersion) {
    reportOpenDatabaseResult(
        6, InvalidStateError, 0,
        WTF::monotonicallyIncreasingTime() - callStartTime);
    errorMessage =
        "unable to open database, version mismatch, '" + m_expectedVersion +
        "' does not match the currentVersion of '" + currentVersion + "'";
    m_sqliteDatabase.close();
    return false;
  }

  ASSERT(m_databaseAuthorizer);
  m_sqliteDatabase.setAuthorizer(m_databaseAuthorizer.get());

  // See comment at the top this file regarding calling addOpenDatabase().
  DatabaseTracker::tracker().addOpenDatabase(this);
  m_opened = 1;

  // Declare success:
  error = DatabaseError::None;  // Clear the presumed error from above.
  onExitCaller.setOpenSucceeded();

  if (m_new && !shouldSetVersionInNewDatabase) {
    // The caller provided a creationCallback which will set the expected
    // version.
    m_expectedVersion = "";
  }

  reportOpenDatabaseResult(
      0, -1, 0, WTF::monotonicallyIncreasingTime() - callStartTime);  // OK

  if (getDatabaseContext()->databaseThread())
    getDatabaseContext()->databaseThread()->recordDatabaseOpen(this);
  return true;
}

String Database::stringIdentifier() const {
  // Return a deep copy for ref counting thread safety
  return m_name.isolatedCopy();
}

String Database::displayName() const {
  // Return a deep copy for ref counting thread safety
  return m_displayName.isolatedCopy();
}

unsigned Database::estimatedSize() const {
  return m_estimatedSize;
}

String Database::fileName() const {
  // Return a deep copy for ref counting thread safety
  return m_filename.isolatedCopy();
}

bool Database::getVersionFromDatabase(String& version,
                                      bool shouldCacheVersion) {
  String query(String("SELECT value FROM ") + infoTableName + " WHERE key = '" +
               versionKey + "';");

  m_databaseAuthorizer->disable();

  bool result =
      retrieveTextResultFromDatabase(m_sqliteDatabase, query, version);
  if (result) {
    if (shouldCacheVersion)
      setCachedVersion(version);
  } else {
    DLOG(ERROR) << "Failed to retrieve version from database "
                << databaseDebugName();
  }

  m_databaseAuthorizer->enable();

  return result;
}

bool Database::setVersionInDatabase(const String& version,
                                    bool shouldCacheVersion) {
  // The INSERT will replace an existing entry for the database with the new
  // version number, due to the UNIQUE ON CONFLICT REPLACE clause in the
  // CREATE statement (see Database::performOpenAndVerify()).
  String query(String("INSERT INTO ") + infoTableName +
               " (key, value) VALUES ('" + versionKey + "', ?);");

  m_databaseAuthorizer->disable();

  bool result = setTextValueInDatabase(m_sqliteDatabase, query, version);
  if (result) {
    if (shouldCacheVersion)
      setCachedVersion(version);
  } else {
    DLOG(ERROR) << "Failed to set version " << version << " in database ("
                << query << ")";
  }

  m_databaseAuthorizer->enable();

  return result;
}

void Database::setExpectedVersion(const String& version) {
  m_expectedVersion = version.isolatedCopy();
}

String Database::getCachedVersion() const {
  SafePointAwareMutexLocker locker(guidMutex());
  return guidToVersionMap().get(m_guid).isolatedCopy();
}

void Database::setCachedVersion(const String& actualVersion) {
  // Update the in memory database version map.
  SafePointAwareMutexLocker locker(guidMutex());
  updateGuidVersionMap(m_guid, actualVersion);
}

bool Database::getActualVersionForTransaction(String& actualVersion) {
  ASSERT(m_sqliteDatabase.transactionInProgress());
  // Note: In multi-process browsers the cached value may be inaccurate. So we
  // retrieve the value from the database and update the cached value here.
  return getVersionFromDatabase(actualVersion, true);
}

void Database::disableAuthorizer() {
  ASSERT(m_databaseAuthorizer);
  m_databaseAuthorizer->disable();
}

void Database::enableAuthorizer() {
  ASSERT(m_databaseAuthorizer);
  m_databaseAuthorizer->enable();
}

void Database::setAuthorizerPermissions(int permissions) {
  ASSERT(m_databaseAuthorizer);
  m_databaseAuthorizer->setPermissions(permissions);
}

bool Database::lastActionChangedDatabase() {
  ASSERT(m_databaseAuthorizer);
  return m_databaseAuthorizer->lastActionChangedDatabase();
}

bool Database::lastActionWasInsert() {
  ASSERT(m_databaseAuthorizer);
  return m_databaseAuthorizer->lastActionWasInsert();
}

void Database::resetDeletes() {
  ASSERT(m_databaseAuthorizer);
  m_databaseAuthorizer->resetDeletes();
}

bool Database::hadDeletes() {
  ASSERT(m_databaseAuthorizer);
  return m_databaseAuthorizer->hadDeletes();
}

void Database::resetAuthorizer() {
  if (m_databaseAuthorizer)
    m_databaseAuthorizer->reset();
}

unsigned long long Database::maximumSize() const {
  return DatabaseTracker::tracker().getMaxSizeForDatabase(this);
}

void Database::incrementalVacuumIfNeeded() {
  int64_t freeSpaceSize = m_sqliteDatabase.freeSpaceSize();
  int64_t totalSize = m_sqliteDatabase.totalSize();
  if (totalSize <= 10 * freeSpaceSize) {
    int result = m_sqliteDatabase.runIncrementalVacuumCommand();
    reportVacuumDatabaseResult(result);
    if (result != SQLResultOk)
      logErrorMessage(formatErrorMessage("error vacuuming database", result,
                                         m_sqliteDatabase.lastErrorMsg()));
  }
}

// These are used to generate histograms of errors seen with websql.
// See about:histograms in chromium.
void Database::reportOpenDatabaseResult(int errorSite,
                                        int webSqlErrorCode,
                                        int sqliteErrorCode,
                                        double duration) {
  if (Platform::current()->databaseObserver()) {
    Platform::current()->databaseObserver()->reportOpenDatabaseResult(
        WebSecurityOrigin(getSecurityOrigin()), stringIdentifier(), errorSite,
        webSqlErrorCode, sqliteErrorCode, duration);
  }
}

void Database::reportChangeVersionResult(int errorSite,
                                         int webSqlErrorCode,
                                         int sqliteErrorCode) {
  if (Platform::current()->databaseObserver()) {
    Platform::current()->databaseObserver()->reportChangeVersionResult(
        WebSecurityOrigin(getSecurityOrigin()), stringIdentifier(), errorSite,
        webSqlErrorCode, sqliteErrorCode);
  }
}

void Database::reportStartTransactionResult(int errorSite,
                                            int webSqlErrorCode,
                                            int sqliteErrorCode) {
  if (Platform::current()->databaseObserver()) {
    Platform::current()->databaseObserver()->reportStartTransactionResult(
        WebSecurityOrigin(getSecurityOrigin()), stringIdentifier(), errorSite,
        webSqlErrorCode, sqliteErrorCode);
  }
}

void Database::reportCommitTransactionResult(int errorSite,
                                             int webSqlErrorCode,
                                             int sqliteErrorCode) {
  if (Platform::current()->databaseObserver()) {
    Platform::current()->databaseObserver()->reportCommitTransactionResult(
        WebSecurityOrigin(getSecurityOrigin()), stringIdentifier(), errorSite,
        webSqlErrorCode, sqliteErrorCode);
  }
}

void Database::reportExecuteStatementResult(int errorSite,
                                            int webSqlErrorCode,
                                            int sqliteErrorCode) {
  if (Platform::current()->databaseObserver()) {
    Platform::current()->databaseObserver()->reportExecuteStatementResult(
        WebSecurityOrigin(getSecurityOrigin()), stringIdentifier(), errorSite,
        webSqlErrorCode, sqliteErrorCode);
  }
}

void Database::reportVacuumDatabaseResult(int sqliteErrorCode) {
  if (Platform::current()->databaseObserver()) {
    Platform::current()->databaseObserver()->reportVacuumDatabaseResult(
        WebSecurityOrigin(getSecurityOrigin()), stringIdentifier(),
        sqliteErrorCode);
  }
}

void Database::logErrorMessage(const String& message) {
  getExecutionContext()->addConsoleMessage(
      ConsoleMessage::create(StorageMessageSource, ErrorMessageLevel, message));
}

ExecutionContext* Database::getExecutionContext() const {
  return getDatabaseContext()->getExecutionContext();
}

void Database::closeImmediately() {
  ASSERT(getExecutionContext()->isContextThread());
  if (getDatabaseContext()->databaseThreadAvailable() && opened()) {
    logErrorMessage("forcibly closing database");
    getDatabaseContext()->databaseThread()->scheduleTask(
        DatabaseCloseTask::create(this, 0));
  }
}

void Database::changeVersion(const String& oldVersion,
                             const String& newVersion,
                             SQLTransactionCallback* callback,
                             SQLTransactionErrorCallback* errorCallback,
                             VoidCallback* successCallback) {
  ChangeVersionData data(oldVersion, newVersion);
  runTransaction(callback, errorCallback, successCallback, false, &data);
}

void Database::transaction(SQLTransactionCallback* callback,
                           SQLTransactionErrorCallback* errorCallback,
                           VoidCallback* successCallback) {
  runTransaction(callback, errorCallback, successCallback, false);
}

void Database::readTransaction(SQLTransactionCallback* callback,
                               SQLTransactionErrorCallback* errorCallback,
                               VoidCallback* successCallback) {
  runTransaction(callback, errorCallback, successCallback, true);
}

static void callTransactionErrorCallback(
    SQLTransactionErrorCallback* callback,
    std::unique_ptr<SQLErrorData> errorData) {
  callback->handleEvent(SQLError::create(*errorData));
}

void Database::runTransaction(SQLTransactionCallback* callback,
                              SQLTransactionErrorCallback* errorCallback,
                              VoidCallback* successCallback,
                              bool readOnly,
                              const ChangeVersionData* changeVersionData) {
  if (!getExecutionContext())
    return;

  ASSERT(getExecutionContext()->isContextThread());
// FIXME: Rather than passing errorCallback to SQLTransaction and then
// sometimes firing it ourselves, this code should probably be pushed down
// into Database so that we only create the SQLTransaction if we're
// actually going to run it.
#if DCHECK_IS_ON()
  SQLTransactionErrorCallback* originalErrorCallback = errorCallback;
#endif
  SQLTransaction* transaction = SQLTransaction::create(
      this, callback, successCallback, errorCallback, readOnly);
  SQLTransactionBackend* transactionBackend =
      runTransaction(transaction, readOnly, changeVersionData);
  if (!transactionBackend) {
    SQLTransactionErrorCallback* callback = transaction->releaseErrorCallback();
    ASSERT(callback == originalErrorCallback);
    if (callback) {
      std::unique_ptr<SQLErrorData> error = SQLErrorData::create(
          SQLError::kUnknownErr, "database has been closed");
      getExecutionContext()->postTask(
          TaskType::DatabaseAccess, BLINK_FROM_HERE,
          createSameThreadTask(&callTransactionErrorCallback,
                               wrapPersistent(callback),
                               WTF::passed(std::move(error))));
    }
  }
}

void Database::scheduleTransactionCallback(SQLTransaction* transaction) {
  // The task is constructed in a database thread, and destructed in the
  // context thread.
  getExecutionContext()->postTask(
      TaskType::DatabaseAccess, BLINK_FROM_HERE,
      createCrossThreadTask(&SQLTransaction::performPendingCallback,
                            wrapCrossThreadPersistent(transaction)));
}

Vector<String> Database::performGetTableNames() {
  disableAuthorizer();

  SQLiteStatement statement(
      sqliteDatabase(), "SELECT name FROM sqlite_master WHERE type='table';");
  if (statement.prepare() != SQLResultOk) {
    DLOG(ERROR) << "Unable to retrieve list of tables for database "
                << databaseDebugName();
    enableAuthorizer();
    return Vector<String>();
  }

  Vector<String> tableNames;
  int result;
  while ((result = statement.step()) == SQLResultRow) {
    String name = statement.getColumnText(0);
    if (name != databaseInfoTableName())
      tableNames.push_back(name);
  }

  enableAuthorizer();

  if (result != SQLResultDone) {
    DLOG(ERROR) << "Error getting tables for database " << databaseDebugName();
    return Vector<String>();
  }

  return tableNames;
}

Vector<String> Database::tableNames() {
  // FIXME: Not using isolatedCopy on these strings looks ok since threads
  // take strict turns in dealing with them. However, if the code changes,
  // this may not be true anymore.
  Vector<String> result;
  WaitableEvent event;
  if (!getDatabaseContext()->databaseThreadAvailable())
    return result;

  std::unique_ptr<DatabaseTableNamesTask> task =
      DatabaseTableNamesTask::create(this, &event, result);
  getDatabaseContext()->databaseThread()->scheduleTask(std::move(task));
  event.wait();

  return result;
}

SecurityOrigin* Database::getSecurityOrigin() const {
  if (!getExecutionContext())
    return nullptr;
  if (getExecutionContext()->isContextThread())
    return m_contextThreadSecurityOrigin.get();
  if (getDatabaseContext()->databaseThread()->isDatabaseThread())
    return m_databaseThreadSecurityOrigin.get();
  return nullptr;
}

bool Database::opened() {
  return static_cast<bool>(acquireLoad(&m_opened));
}

}  // namespace blink