/*

 * Copyright (C) 2010 Google 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.

 * 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.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "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 OR ITS 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 "config.h"

#include "AbstractDatabase.h"

#if ENABLE(DATABASE)

#include "DatabaseAuthorizer.h"

#include "DatabaseTracker.h"

#include "Logging.h"

#include "SQLiteStatement.h"

#include "ScriptExecutionContext.h"

#include "SecurityOrigin.h"

#include "StringHash.h"

#include <wtf/HashMap.h>

#include <wtf/HashSet.h>

#include <wtf/PassRefPtr.h>

#include <wtf/RefPtr.h>

#include <wtf/StdLibExtras.h>

namespace WebCore {

static bool retrieveTextResultFromDatabase(SQLiteDatabase& db, const String& query, String& resultString)

{

    SQLiteStatement statement(db, query);

    int result = statement.prepare();

    if (result != SQLResultOk) {

        LOG_ERROR("Error (%i) preparing statement to read text result from database (%s)", result, query.ascii().data());

        return false;

    }

    result = statement.step();

    if (result == SQLResultRow) {

        resultString = statement.getColumnText(0);

        return true;

    }

    if (result == SQLResultDone) {

        resultString = String();

        return true;

    }

    LOG_ERROR("Error (%i) reading text result from database (%s)", result, query.ascii().data());

    return false;

}

static bool setTextValueInDatabase(SQLiteDatabase& db, const String& query, const String& value)

{

    SQLiteStatement statement(db, query);

    int result = statement.prepare();

    if (result != SQLResultOk) {

        LOG_ERROR("Failed to prepare statement to set value in database (%s)", query.ascii().data());

        return false;

    }

    statement.bindText(1, value);

    result = statement.step();

    if (result != SQLResultDone) {

        LOG_ERROR("Failed to step statement to set value in database (%s)", query.ascii().data());

        return false;

    }

    return true;

}

// FIXME: move all guid-related functions to a DatabaseVersionTracker class.

static Mutex& guidMutex()

{

    // Note: We don't have to use AtomicallyInitializedStatic here because

    // this function is called once in the constructor on the main thread

    // before any other threads that call this function are used.

    DEFINE_STATIC_LOCAL(Mutex, mutex, ());

    return mutex;

}

typedef HashMap<int, String> GuidVersionMap;

static GuidVersionMap& guidToVersionMap()

{

    DEFINE_STATIC_LOCAL(GuidVersionMap, map, ());

    return map;

}

// NOTE: Caller must lock guidMutex().

static inline void updateGuidVersionMap(int guid, String newVersion)

{

    // Ensure the the mutex is locked.

    ASSERT(!guidMutex().tryLock());

    // 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.threadsafeCopy());

}

typedef HashMap<int, HashSet<AbstractDatabase*>*> GuidDatabaseMap;

static GuidDatabaseMap& guidToDatabaseMap()

{

    DEFINE_STATIC_LOCAL(GuidDatabaseMap, map, ());

    return map;

}

static int guidForOriginAndName(const String& origin, const String& name)

{

    String stringID = origin + "/" + name;

    // Note: We don't have to use AtomicallyInitializedStatic here because

    // this function is called once in the constructor on the main thread

    // before any other threads that call this function are used.

    DEFINE_STATIC_LOCAL(Mutex, stringIdentifierMutex, ());

    MutexLocker locker(stringIdentifierMutex);

    typedef HashMap<String, int> IDGuidMap;

    DEFINE_STATIC_LOCAL(IDGuidMap, stringIdentifierToGUIDMap, ());

    int guid = stringIdentifierToGUIDMap.get(stringID);

    if (!guid) {

        static int currentNewGUID = 1;

        guid = currentNewGUID++;

        stringIdentifierToGUIDMap.set(stringID, guid);

    }

    return guid;

}

static bool isDatabaseAvailable = true;

bool AbstractDatabase::isAvailable()

{

    return isDatabaseAvailable;

}

void AbstractDatabase::setIsAvailable(bool available)

{

    isDatabaseAvailable = available;

}

// static

const String& AbstractDatabase::databaseInfoTableName()

{

    DEFINE_STATIC_LOCAL(String, name, ("__WebKitDatabaseInfoTable__"));

    return name;

}

AbstractDatabase::AbstractDatabase(ScriptExecutionContext* context, const String& name, const String& expectedVersion,

                                   const String& displayName, unsigned long estimatedSize)

    : m_scriptExecutionContext(context)

    , m_name(name.crossThreadString())

    , m_expectedVersion(expectedVersion.crossThreadString())

    , m_displayName(displayName.crossThreadString())

    , m_estimatedSize(estimatedSize)

    , m_guid(0)

    , m_opened(false)

    , m_new(false)

{

    ASSERT(context->isContextThread());

    m_contextThreadSecurityOrigin = m_scriptExecutionContext->securityOrigin();

    m_databaseAuthorizer = DatabaseAuthorizer::create(databaseInfoTableName());

    if (m_name.isNull())

        m_name = "";

    m_guid = guidForOriginAndName(securityOrigin()->toString(), name);

    {

        MutexLocker locker(guidMutex());

        HashSet<AbstractDatabase*>* hashSet = guidToDatabaseMap().get(m_guid);

        if (!hashSet) {

            hashSet = new HashSet<AbstractDatabase*>;

            guidToDatabaseMap().set(m_guid, hashSet);

        }

        hashSet->add(this);

    }

    m_filename = DatabaseTracker::tracker().fullPathForDatabase(securityOrigin(), m_name);

    DatabaseTracker::tracker().addOpenDatabase(this);

}

AbstractDatabase::~AbstractDatabase()

{

}

void AbstractDatabase::closeDatabase()

{

    if (!m_opened)

        return;

    m_sqliteDatabase.close();

    m_opened = false;

    {

        MutexLocker locker(guidMutex());

        HashSet<AbstractDatabase*>* hashSet = guidToDatabaseMap().get(m_guid);

        ASSERT(hashSet);

        ASSERT(hashSet->contains(this));

        hashSet->remove(this);

        if (hashSet->isEmpty()) {

            guidToDatabaseMap().remove(m_guid);

            delete hashSet;

            guidToVersionMap().remove(m_guid);

        }

    }

}

String AbstractDatabase::version() const

{

    MutexLocker locker(guidMutex());

    return guidToVersionMap().get(m_guid).threadsafeCopy();

}

static const int maxSqliteBusyWaitTime = 30000;

bool AbstractDatabase::performOpenAndVerify(bool shouldSetVersionInNewDatabase, ExceptionCode& ec)

{

    if (!m_sqliteDatabase.open(m_filename, true)) {

        LOG_ERROR("Unable to open database at path %s", m_filename.ascii().data());

        ec = INVALID_STATE_ERR;

        return false;

    }

    if (!m_sqliteDatabase.turnOnIncrementalAutoVacuum())

        LOG_ERROR("Unable to turn on incremental auto-vacuum for database %s", m_filename.ascii().data());

    ASSERT(m_databaseAuthorizer);

    m_sqliteDatabase.setAuthorizer(m_databaseAuthorizer);

    m_sqliteDatabase.setBusyTimeout(maxSqliteBusyWaitTime);

    String currentVersion;

    {

        MutexLocker locker(guidMutex());

        GuidVersionMap::iterator entry = guidToVersionMap().find(m_guid);

        if (entry != guidToVersionMap().end()) {

            // Map null string to empty string (see updateGuidVersionMap()).

            currentVersion = entry->second.isNull() ? String("") : entry->second;

            LOG(StorageAPI, "Current cached version for guid %i is %s", m_guid, currentVersion.ascii().data());

        } else {

            LOG(StorageAPI, "No cached version for guid %i", m_guid);

            if (!m_sqliteDatabase.tableExists(databaseInfoTableName())) {

                m_new = true;

                if (!m_sqliteDatabase.executeCommand("CREATE TABLE " + databaseInfoTableName() + " (key TEXT NOT NULL ON CONFLICT FAIL UNIQUE ON CONFLICT REPLACE,value TEXT NOT NULL ON CONFLICT FAIL);")) {

                    LOG_ERROR("Unable to create table %s in database %s", databaseInfoTableName().ascii().data(), databaseDebugName().ascii().data());

                    ec = INVALID_STATE_ERR;

                    // Close the handle to the database file.

                    m_sqliteDatabase.close();

                    return false;

                }

            }

            if (!getVersionFromDatabase(currentVersion)) {

                LOG_ERROR("Failed to get current version from database %s", databaseDebugName().ascii().data());

                ec = INVALID_STATE_ERR;

                // Close the handle to the database file.

                m_sqliteDatabase.close();

                return false;

            }

            if (currentVersion.length()) {

                LOG(StorageAPI, "Retrieved current version %s from database %s", currentVersion.ascii().data(), databaseDebugName().ascii().data());

            } else if (!m_new || shouldSetVersionInNewDatabase) {

                LOG(StorageAPI, "Setting version %s in database %s that was just created", m_expectedVersion.ascii().data(), databaseDebugName().ascii().data());

                if (!setVersionInDatabase(m_expectedVersion)) {

                    LOG_ERROR("Failed to set version %s in database %s", m_expectedVersion.ascii().data(), databaseDebugName().ascii().data());

                    ec = INVALID_STATE_ERR;

                    // Close the handle to the database file.

                    m_sqliteDatabase.close();

                    return false;

                }

                currentVersion = m_expectedVersion;

            }

            updateGuidVersionMap(m_guid, currentVersion);

        }

    }

    if (currentVersion.isNull()) {

        LOG(StorageAPI, "Database %s does not have its version set", databaseDebugName().ascii().data());

        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) {

        LOG(StorageAPI, "page expects version %s from database %s, which actually has version name %s - openDatabase() call will fail", m_expectedVersion.ascii().data(),

            databaseDebugName().ascii().data(), currentVersion.ascii().data());

        ec = INVALID_STATE_ERR;

        // Close the handle to the database file.

        m_sqliteDatabase.close();

        return false;

    }

    m_opened = true;

    return true;

}

ScriptExecutionContext* AbstractDatabase::scriptExecutionContext() const

{

    return m_scriptExecutionContext.get();

}

SecurityOrigin* AbstractDatabase::securityOrigin() const

{

    return m_contextThreadSecurityOrigin.get();

}

String AbstractDatabase::stringIdentifier() const

{

    // Return a deep copy for ref counting thread safety

    return m_name.threadsafeCopy();

}

String AbstractDatabase::displayName() const

{

    // Return a deep copy for ref counting thread safety

    return m_displayName.threadsafeCopy();

}

unsigned long AbstractDatabase::estimatedSize() const

{

    return m_estimatedSize;

}

String AbstractDatabase::fileName() const

{

    // Return a deep copy for ref counting thread safety

    return m_filename.threadsafeCopy();

}

// static

const String& AbstractDatabase::databaseVersionKey()

{

    DEFINE_STATIC_LOCAL(String, key, ("WebKitDatabaseVersionKey"));

    return key;

}

bool AbstractDatabase::getVersionFromDatabase(String& version)

{

    DEFINE_STATIC_LOCAL(String, getVersionQuery, ("SELECT value FROM " + databaseInfoTableName() + " WHERE key = '" + databaseVersionKey() + "';"));

    m_databaseAuthorizer->disable();

    bool result = retrieveTextResultFromDatabase(m_sqliteDatabase, getVersionQuery.threadsafeCopy(), version);

    if (!result)

        LOG_ERROR("Failed to retrieve version from database %s", databaseDebugName().ascii().data());

    m_databaseAuthorizer->enable();

    return result;

}

bool AbstractDatabase::setVersionInDatabase(const String& version)

{

    // 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()).

    DEFINE_STATIC_LOCAL(String, setVersionQuery, ("INSERT INTO " + databaseInfoTableName() + " (key, value) VALUES ('" + databaseVersionKey() + "', ?);"));

    m_databaseAuthorizer->disable();

    bool result = setTextValueInDatabase(m_sqliteDatabase, setVersionQuery.threadsafeCopy(), version);

    if (!result)

        LOG_ERROR("Failed to set version %s in database (%s)", version.ascii().data(), setVersionQuery.ascii().data());

    m_databaseAuthorizer->enable();

    return result;

}

bool AbstractDatabase::versionMatchesExpected() const

{

    if (!m_expectedVersion.isEmpty()) {

        MutexLocker locker(guidMutex());

        return m_expectedVersion == guidToVersionMap().get(m_guid);

    }

    return true;

}

void AbstractDatabase::setExpectedVersion(const String& version)

{

    m_expectedVersion = version.threadsafeCopy();

    // Update the in memory database version map.

    MutexLocker locker(guidMutex());

    updateGuidVersionMap(m_guid, version);

}

void AbstractDatabase::disableAuthorizer()

{

    ASSERT(m_databaseAuthorizer);

    m_databaseAuthorizer->disable();

}

void AbstractDatabase::enableAuthorizer()

{

    ASSERT(m_databaseAuthorizer);

    m_databaseAuthorizer->enable();

}

void AbstractDatabase::setAuthorizerReadOnly()

{

    ASSERT(m_databaseAuthorizer);

    m_databaseAuthorizer->setReadOnly();

}

bool AbstractDatabase::lastActionChangedDatabase()

{

    ASSERT(m_databaseAuthorizer);

    return m_databaseAuthorizer->lastActionChangedDatabase();

}

bool AbstractDatabase::lastActionWasInsert()

{

    ASSERT(m_databaseAuthorizer);

    return m_databaseAuthorizer->lastActionWasInsert();

}

void AbstractDatabase::resetDeletes()

{

    ASSERT(m_databaseAuthorizer);

    m_databaseAuthorizer->resetDeletes();

}

bool AbstractDatabase::hadDeletes()

{

    ASSERT(m_databaseAuthorizer);

    return m_databaseAuthorizer->hadDeletes();

}

void AbstractDatabase::resetAuthorizer()

{

    if (m_databaseAuthorizer)

        m_databaseAuthorizer->reset();

}

unsigned long long AbstractDatabase::maximumSize() const

{

    return DatabaseTracker::tracker().getMaxSizeForDatabase(this);

}

void AbstractDatabase::incrementalVacuumIfNeeded()

{

    int64_t freeSpaceSize = m_sqliteDatabase.freeSpaceSize();

    int64_t totalSize = m_sqliteDatabase.totalSize();

    if (totalSize <= 10 * freeSpaceSize)

        m_sqliteDatabase.runIncrementalVacuumCommand();

}

} // namespace WebCore

#endif // ENABLE(DATABASE)