sqltransaction.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
 * Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
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 * 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
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 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
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#include "config.h"
#include "SQLTransaction.h"

#include "ChromeClient.h"
#include "Database.h"
#include "DatabaseAuthorizer.h"
#include "DatabaseDetails.h"
#include "DatabaseTracker.h"
#include "Document.h"
#include "ExceptionCode.h"
#include "Logging.h"
#include "OriginQuotaManager.h"
#include "Page.h"
#include "PlatformString.h"
#include "SecurityOrigin.h"
#include "SQLError.h"
#include "SQLiteTransaction.h"
#include "SQLResultSet.h"
#include "SQLStatement.h"
#include "SQLStatementCallback.h"
#include "SQLStatementErrorCallback.h"
#include "SQLValue.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)
{
    return adoptRef(new SQLTransaction(db, callback, errorCallback, successCallback, wrapper));
}

SQLTransaction::SQLTransaction(Database* db, PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback, PassRefPtr<VoidCallback> successCallback, 
                               PassRefPtr<SQLTransactionWrapper> wrapper)
    : m_nextStep(&SQLTransaction::openTransactionAndPreflight)
    , m_executeSqlAllowed(false)
    , m_database(db)
    , m_wrapper(wrapper)
    , m_callback(callback)
    , m_successCallback(successCallback)
    , m_errorCallback(errorCallback)
    , m_shouldRetryCurrentStatement(false)
    , m_shouldCommitAfterErrorCallback(true)
    , m_modifiedDatabase(false)
{
    ASSERT(m_database);
}

SQLTransaction::~SQLTransaction()
{
}

void SQLTransaction::executeSQL(const String& sqlStatement, const Vector<SQLValue>& arguments, PassRefPtr<SQLStatementCallback> callback, PassRefPtr<SQLStatementErrorCallback> callbackError, ExceptionCode& e)
{
    if (!m_executeSqlAllowed || m_database->stopped()) {
        e = INVALID_STATE_ERR;
        return;
    }
    
    RefPtr<SQLStatement> statement = SQLStatement::create(sqlStatement.copy(), arguments, callback, callbackError);

    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::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->stopped())
        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 current SQLite transaction should be stopped, as well
    if (m_sqliteTransaction) {
        m_sqliteTransaction->stop();
        m_sqliteTransaction.clear();
    }
}


bool SQLTransaction::performNextStep()
{
    LOG(StorageAPI, "Step %s\n", debugStepName(m_nextStep));

    ASSERT(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::openTransactionAndPreflight()
{
    ASSERT(!m_database->m_sqliteDatabase.transactionInProgress());

    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(0, "unable to open a transaction, because the user deleted the database");
        handleTransactionError(false);
        return;
    }

    // Set the maximum usage for this transaction
    m_database->m_sqliteDatabase.setMaximumSize(m_database->maximumSize());
    
    ASSERT(!m_sqliteTransaction);
    m_sqliteTransaction.set(new SQLiteTransaction(m_database->m_sqliteDatabase));
    
    m_database->m_databaseAuthorizer->disable();
    m_sqliteTransaction->begin();
    m_database->m_databaseAuthorizer->enable();    
    
    // 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->m_sqliteDatabase.transactionInProgress());
        m_sqliteTransaction.clear();
        m_transactionError = SQLError::create(0, "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->m_sqliteDatabase.transactionInProgress());
        m_sqliteTransaction.clear();
        m_transactionError = m_wrapper->sqlError();
        if (!m_transactionError)
            m_transactionError = SQLError::create(0, "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;
        m_callback->handleEvent(this, shouldDeliverErrorCallback);
        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(0, "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()
{
    // 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_shouldRetryCurrentStatement = false;
            // FIXME - Another place that needs fixing up after <rdar://problem/5628468> is addressed.
            // See ::openTransactionAndPreflight() for discussion