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 *     notice, this list of conditions and the following disclaimer.

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#include "config.h"

#include "SQLTransaction.h"

#if ENABLE(DATABASE)

#include "Database.h"

#include "DatabaseThread.h"

#include "Logging.h"

#include "PlatformString.h"

#include "ScriptExecutionContext.h"

#include "SQLError.h"

#include "SQLiteTransaction.h"

#include "SQLStatement.h"

#include "SQLStatementCallback.h"

#include "SQLStatementErrorCallback.h"

#include "SQLTransactionCallback.h"

#include "SQLTransactionClient.h"

#include "SQLTransactionCoordinator.h"

#include "SQLTransactionErrorCallback.h"

#include "SQLValue.h"

#include "VoidCallback.h"

#include <wtf/OwnPtr.h>

#include <wtf/PassRefPtr.h>

#include <wtf/RefPtr.h>

// There's no way of knowing exactly how much more space will be required when a statement hits the quota limit.

// For now, we'll arbitrarily choose currentQuota + 1mb.

// In the future we decide to track if a size increase wasn't enough, and ask for larger-and-larger increases until its enough.

static const int DefaultQuotaSizeIncrease = 1048576;

namespace WebCore {

PassRefPtr<SQLTransaction> SQLTransaction::create(Database* db, PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback,

                                                  PassRefPtr<VoidCallback> successCallback, PassRefPtr<SQLTransactionWrapper> wrapper, bool readOnly)

{

    return adoptRef(new SQLTransaction(db, callback, errorCallback, successCallback, wrapper, readOnly));

}

SQLTransaction::SQLTransaction(Database* db, PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback,

                               PassRefPtr<VoidCallback> successCallback, PassRefPtr<SQLTransactionWrapper> wrapper, bool readOnly)

    : m_nextStep(&SQLTransaction::acquireLock)

    , m_executeSqlAllowed(false)

    , m_database(db)

    , m_wrapper(wrapper)

    , m_callback(callback)

    , m_successCallback(successCallback)

    , m_errorCallback(errorCallback)

    , m_shouldRetryCurrentStatement(false)

    , m_modifiedDatabase(false)

    , m_lockAcquired(false)

    , m_readOnly(readOnly)

{

    ASSERT(m_database);

}

SQLTransaction::~SQLTransaction()

{

    ASSERT(!m_sqliteTransaction);

}

void SQLTransaction::executeSQL(const String& sqlStatement, const Vector<SQLValue>& arguments, PassRefPtr<SQLStatementCallback> callback, PassRefPtr<SQLStatementErrorCallback> callbackError, ExceptionCode& e)

{

    if (!m_executeSqlAllowed || !m_database->opened()) {

        e = INVALID_STATE_ERR;

        return;

    }

    bool readOnlyMode = m_readOnly;

    if (!readOnlyMode) {

        if (m_database->scriptExecutionContext()->isDatabaseReadOnly())

            readOnlyMode = true;

    }

    RefPtr<SQLStatement> statement = SQLStatement::create(sqlStatement, arguments, callback, callbackError, readOnlyMode);

    if (m_database->deleted())

        statement->setDatabaseDeletedError();

    if (!m_database->versionMatchesExpected())

        statement->setVersionMismatchedError();

    enqueueStatement(statement);

}

void SQLTransaction::enqueueStatement(PassRefPtr<SQLStatement> statement)

{

    MutexLocker locker(m_statementMutex);

    m_statementQueue.append(statement);

}

#ifndef NDEBUG

const char* SQLTransaction::debugStepName(SQLTransaction::TransactionStepMethod step)

{

    if (step == &SQLTransaction::acquireLock)

        return "acquireLock";

    else if (step == &SQLTransaction::openTransactionAndPreflight)

        return "openTransactionAndPreflight";

    else if (step == &SQLTransaction::runStatements)

        return "runStatements";

    else if (step == &SQLTransaction::postflightAndCommit)

        return "postflightAndCommit";

    else if (step == &SQLTransaction::cleanupAfterTransactionErrorCallback)

        return "cleanupAfterTransactionErrorCallback";

    else if (step == &SQLTransaction::deliverTransactionCallback)

        return "deliverTransactionCallback";

    else if (step == &SQLTransaction::deliverTransactionErrorCallback)

        return "deliverTransactionErrorCallback";

    else if (step == &SQLTransaction::deliverStatementCallback)

        return "deliverStatementCallback";

    else if (step == &SQLTransaction::deliverQuotaIncreaseCallback)

        return "deliverQuotaIncreaseCallback";

    else if (step == &SQLTransaction::deliverSuccessCallback)

        return "deliverSuccessCallback";

    else if (step == &SQLTransaction::cleanupAfterSuccessCallback)

        return "cleanupAfterSuccessCallback";

    else

        return "UNKNOWN";

}

#endif

void SQLTransaction::checkAndHandleClosedDatabase()

{

    if (m_database->opened())

        return;

    // If the database was stopped, don't do anything and cancel queued work

    LOG(StorageAPI, "Database was stopped - cancelling work for this transaction");

    MutexLocker locker(m_statementMutex);

    m_statementQueue.clear();

    m_nextStep = 0;

    // The next steps should be executed only if we're on the DB thread.

    if (currentThread() != database()->scriptExecutionContext()->databaseThread()->getThreadID())

        return;

    // The current SQLite transaction should be stopped, as well

    if (m_sqliteTransaction) {

        m_sqliteTransaction->stop();

        m_sqliteTransaction.clear();

    }

    if (m_lockAcquired)

        m_database->transactionCoordinator()->releaseLock(this);

}

bool SQLTransaction::performNextStep()

{

    LOG(StorageAPI, "Step %s\n", debugStepName(m_nextStep));

    ASSERT(m_nextStep == &SQLTransaction::acquireLock ||

           m_nextStep == &SQLTransaction::openTransactionAndPreflight ||

           m_nextStep == &SQLTransaction::runStatements ||

           m_nextStep == &SQLTransaction::postflightAndCommit ||

           m_nextStep == &SQLTransaction::cleanupAfterSuccessCallback ||

           m_nextStep == &SQLTransaction::cleanupAfterTransactionErrorCallback);

    checkAndHandleClosedDatabase();

    if (m_nextStep)

        (this->*m_nextStep)();

    // If there is no nextStep after performing the above step, the transaction is complete

    return !m_nextStep;

}

void SQLTransaction::performPendingCallback()

{

    LOG(StorageAPI, "Callback %s\n", debugStepName(m_nextStep));

    ASSERT(m_nextStep == &SQLTransaction::deliverTransactionCallback ||

           m_nextStep == &SQLTransaction::deliverTransactionErrorCallback ||

           m_nextStep == &SQLTransaction::deliverStatementCallback ||

           m_nextStep == &SQLTransaction::deliverQuotaIncreaseCallback ||

           m_nextStep == &SQLTransaction::deliverSuccessCallback);

    checkAndHandleClosedDatabase();

    if (m_nextStep)

        (this->*m_nextStep)();

}

void SQLTransaction::notifyDatabaseThreadIsShuttingDown()

{

    ASSERT(currentThread() == database()->scriptExecutionContext()->databaseThread()->getThreadID());

    // If the transaction is in progress, we should roll it back here, since this is our last

    // oportunity to do something related to this transaction on the DB thread.

    // Clearing m_sqliteTransaction invokes SQLiteTransaction's destructor which does just that.

    m_sqliteTransaction.clear();

}

void SQLTransaction::acquireLock()

{

    m_database->transactionCoordinator()->acquireLock(this);

}

void SQLTransaction::lockAcquired()

{

    m_lockAcquired = true;

    m_nextStep = &SQLTransaction::openTransactionAndPreflight;

    LOG(StorageAPI, "Scheduling openTransactionAndPreflight immediately for transaction %p\n", this);

    m_database->scheduleTransactionStep(this, true);

}

void SQLTransaction::openTransactionAndPreflight()

{

    ASSERT(!m_database->sqliteDatabase().transactionInProgress());

    ASSERT(m_lockAcquired);

    LOG(StorageAPI, "Opening and preflighting transaction %p", this);

    // If the database was deleted, jump to the error callback

    if (m_database->deleted()) {

        m_transactionError = SQLError::create(SQLError::UNKNOWN_ERR, "unable to open a transaction, because the user deleted the database");

        handleTransactionError(false);

        return;

    }

    // Set the maximum usage for this transaction if this transactions is not read-only

    if (!m_readOnly)

        m_database->sqliteDatabase().setMaximumSize(m_database->maximumSize());

    ASSERT(!m_sqliteTransaction);

    m_sqliteTransaction.set(new SQLiteTransaction(m_database->sqliteDatabase(), m_readOnly));

    m_database->resetDeletes();

    m_database->disableAuthorizer();

    m_sqliteTransaction->begin();

    m_database->enableAuthorizer();

    // Transaction Steps 1+2 - Open a transaction to the database, jumping to the error callback if that fails

    if (!m_sqliteTransaction->inProgress()) {

        ASSERT(!m_database->sqliteDatabase().transactionInProgress());

        m_sqliteTransaction.clear();

        m_transactionError = SQLError::create(SQLError::DATABASE_ERR, "unable to open a transaction to the database");

        handleTransactionError(false);

        return;

    }

    // Transaction Steps 3 - Peform preflight steps, jumping to the error callback if they fail

    if (m_wrapper && !m_wrapper->performPreflight(this)) {

        ASSERT(!m_database->sqliteDatabase().transactionInProgress());

        m_sqliteTransaction.clear();

        m_transactionError = m_wrapper->sqlError();

        if (!m_transactionError)

            m_transactionError = SQLError::create(SQLError::UNKNOWN_ERR, "unknown error occured setting up transaction");

        handleTransactionError(false);

        return;

    }

    // Transaction Step 4 - Invoke the transaction callback with the new SQLTransaction object

    m_nextStep = &SQLTransaction::deliverTransactionCallback;

    LOG(StorageAPI, "Scheduling deliverTransactionCallback for transaction %p\n", this);

    m_database->scheduleTransactionCallback(this);

}

void SQLTransaction::deliverTransactionCallback()

{

    bool shouldDeliverErrorCallback = false;

    if (m_callback) {

        m_executeSqlAllowed = true;

        shouldDeliverErrorCallback = !m_callback->handleEvent(m_database->scriptExecutionContext(), this);

        m_executeSqlAllowed = false;

    } else

        shouldDeliverErrorCallback = true;

    // Transaction Step 5 - If the transaction callback was null or raised an exception, jump to the error callback

    if (shouldDeliverErrorCallback) {

        m_transactionError = SQLError::create(SQLError::UNKNOWN_ERR, "the SQLTransactionCallback was null or threw an exception");

        deliverTransactionErrorCallback();

    } else

        scheduleToRunStatements();

}

void SQLTransaction::scheduleToRunStatements()

{

    m_nextStep = &SQLTransaction::runStatements;

    LOG(StorageAPI, "Scheduling runStatements for transaction %p\n", this);

    m_database->scheduleTransactionStep(this);

}

void SQLTransaction::runStatements()

{

    ASSERT(m_lockAcquired);

    // If there is a series of statements queued up that are all successful and have no associated

    // SQLStatementCallback objects, then we can burn through the queue

    do {

        if (m_shouldRetryCurrentStatement && !m_sqliteTransaction->wasRolledBackBySqlite()) {

            m_shouldRetryCurrentStatement = false;

            // FIXME - Another place that needs fixing up after <rdar://problem/5628468> is addressed.

            // See ::openTransactionAndPreflight() for discussion

            // Reset the maximum size here, as it was increased to allow us to retry this statement.

            // m_shouldRetryCurrentStatement is set to true only when a statement exceeds

            // the quota, which can happen only in a read-write transaction. Therefore, there

            // is no need to check here if the transaction is read-write.

            m_database->sqliteDatabase().setMaximumSize(m_database->maximumSize());

        } else {

            // If the current statement has already been run, failed due to quota constraints, and we're not retrying it,

            // that means it ended in an error.  Handle it now

            if (m_currentStatement && m_currentStatement->lastExecutionFailedDueToQuota()) {

                handleCurrentStatementError();

                break;

            }

            // Otherwise, advance to the next statement

            getNextStatement();

        }

    } while (runCurrentStatement());

    // If runCurrentStatement() returned false, that means either there was no current statement to run,

    // or the current statement requires a callback to complete.  In the later case, it also scheduled

    // the callback or performed any other additional work so we can return

    if (!m_currentStatement)

        postflightAndCommit();

}

void SQLTransaction::getNextStatement()

{

    m_currentStatement = 0;

    MutexLocker locker(m_statementMutex);

    if (!m_statementQueue.isEmpty()) {

        m_currentStatement = m_statementQueue.takeFirst();

    }

}

bool SQLTransaction::runCurrentStatement()

{

    if (!m_currentStatement)

        return false;

    m_database->resetAuthorizer();

    if (m_currentStatement->execute(m_database.get())) {

        if (m_database->lastActionChangedDatabase()) {

            // Flag this transaction as having changed the database for later delegate notification

            m_modifiedDatabase = true;

            // Also dirty the size of this database file for calculating quota usage

            m_database->transactionClient()->didExecuteStatement(database());

        }

        if (m_currentStatement->hasStatementCallback()) {

            m_nextStep = &SQLTransaction::deliverStatementCallback;

            LOG(StorageAPI, "Scheduling deliverStatementCallback for transaction %p\n", this);

            m_database->scheduleTransactionCallback(this);

            return false;

        }

        return true;

    }

    if (m_currentStatement->lastExecutionFailedDueToQuota()) {

        m_nextStep = &SQLTransaction::deliverQuotaIncreaseCallback;

        LOG(StorageAPI, "Scheduling deliverQuotaIncreaseCallback for transaction %p\n", this);

        m_database->scheduleTransactionCallback(this);

        return false;

    }

    handleCurrentStatementError();

    return false;

}

void SQLTransaction::handleCurrentStatementError()

{

    // Transaction Steps 6.error - Call the statement's error callback, but if there was no error callback,

    // or the transaction was rolled back, jump to the transaction error callback

    if (m_currentStatement->hasStatementErrorCallback() && !m_sqliteTransaction->wasRolledBackBySqlite()) {

        m_nextStep = &SQLTransaction::deliverStatementCallback;

        LOG(StorageAPI, "Scheduling deliverStatementCallback for transaction %p\n", this);

        m_database->scheduleTransactionCallback(this);

    } else {

        m_transactionError = m_currentStatement->sqlError();

        if (!m_transactionError)

            m_transactionError = SQLError::create(SQLError::DATABASE_ERR, "the statement failed to execute");

        handleTransactionError(false);

    }

}

void SQLTransaction::deliverStatementCallback()

{

    ASSERT(m_currentStatement);

    // Transaction Step 6.6 and 6.3(error) - If the statement callback went wrong, jump to the transaction error callback

    // Otherwise, continue to loop through the statement queue

    m_executeSqlAllowed = true;

    bool result = m_currentStatement->performCallback(this);

    m_executeSqlAllowed = false;

    if (result) {

      m_transactionError = SQLError::create(SQLError::UNKNOWN_ERR, "the statement callback raised an exception or statement error callback did not return false");

        handleTransactionError(true);

    } else

        scheduleToRunStatements();

}

void SQLTransaction::deliverQuotaIncreaseCallback()

{

    ASSERT(m_currentStatement);

    ASSERT(!m_shouldRetryCurrentStatement);

    m_shouldRetryCurrentStatement = m_database->transactionClient()->didExceedQuota(database());

    m_nextStep = &SQLTransaction::runStatements;

    LOG(StorageAPI, "Scheduling runStatements for transaction %p\n", this);

    m_database->scheduleTransactionStep(this);

}

void SQLTransaction::postflightAndCommit()

{

    ASSERT(m_lockAcquired);

    // Transaction Step 7 - Peform postflight steps, jumping to the error callback if they fail

    if (m_wrapper && !m_wrapper->performPostflight(this)) {

        m_transactionError = m_wrapper->sqlError();

        if (!m_transactionError)

            m_transactionError = SQLError::create(SQLError::UNKNOWN_ERR, "unknown error occured setting up transaction");

        handleTransactionError(false);

        return;

    }

    // Transacton Step 8+9 - Commit the transaction, jumping to the error callback if that fails

    ASSERT(m_sqliteTransaction);

    m_database->disableAuthorizer();

    m_sqliteTransaction->commit();

    m_database->enableAuthorizer();

    // If the commit failed, the transaction will still be marked as "in progress"

    if (m_sqliteTransaction->inProgress()) {

        m_transactionError = SQLError::create(SQLError::DATABASE_ERR, "failed to commit the transaction");

        handleTransactionError(false);

        return;

    }

    // Vacuum the database if anything was deleted.

    if (m_database->hadDeletes())

        m_database->incrementalVacuumIfNeeded();

    // The commit was successful. If the transaction modified this database, notify the delegates.

    if (m_modifiedDatabase)

        m_database->transactionClient()->didCommitWriteTransaction(database());

    // Now release our unneeded callbacks, to break reference cycles.

    m_callback = 0;

    m_errorCallback = 0;

    // Transaction Step 10 - Deliver success callback, if there is one

    if (m_successCallback) {

        m_nextStep = &SQLTransaction::deliverSuccessCallback;

        LOG(StorageAPI, "Scheduling deliverSuccessCallback for transaction %p\n", this);

        m_database->scheduleTransactionCallback(this);

    } else

        cleanupAfterSuccessCallback();

}

void SQLTransaction::deliverSuccessCallback()

{

    // Transaction Step 10 - Deliver success callback

    ASSERT(m_successCallback);

    m_successCallback->handleEvent();

    // Release the last callback to break reference cycle

    m_successCallback = 0;

    // Schedule a "post-success callback" step to return control to the database thread in case there

    // are further transactions queued up for this Database

    m_nextStep = &SQLTransaction::cleanupAfterSuccessCallback;

    LOG(StorageAPI, "Scheduling cleanupAfterSuccessCallback for transaction %p\n", this);

    m_database->scheduleTransactionStep(this);

}

void SQLTransaction::cleanupAfterSuccessCallback()

{

    ASSERT(m_lockAcquired);

    // Transaction Step 11 - End transaction steps

    // There is no next step

    LOG(StorageAPI, "Transaction %p is complete\n", this);

    ASSERT(!m_database->sqliteDatabase().transactionInProgress());

    m_sqliteTransaction.clear();

    m_nextStep = 0;

    // Release the lock on this database

    m_database->transactionCoordinator()->releaseLock(this);

}

void SQLTransaction::handleTransactionError(bool inCallback)

{

    if (m_errorCallback) {

        if (inCallback)

            deliverTransactionErrorCallback();

        else {

            m_nextStep = &SQLTransaction::deliverTransactionErrorCallback;

            LOG(StorageAPI, "Scheduling deliverTransactionErrorCallback for transaction %p\n", this);

            m_database->scheduleTransactionCallback(this);