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#include <QtCore/qobject.h>
#include <qmlengine.h>
#include "qmlengine_p.h"
#include <QtScript/qscriptvalue.h>
#include <QtScript/qscriptvalueiterator.h>
#include <QtScript/qscriptcontext.h>
#include <QtScript/qscriptengine.h>
#include <QtScript/qscriptclasspropertyiterator.h>
#include <QtSql/qsqldatabase.h>
#include <QtSql/qsqlquery.h>
#include <QtSql/qsqlerror.h>
#include <QtSql/qsqlrecord.h>
#include "qmlrefcount_p.h"
#include "qmlengine_p.h"
#include <QtCore/qstack.h>
#include <QtCore/qcryptographichash.h>
#include "qmlsqldatabase_p.h"
#include <QtCore/qsettings.h>
#include <QtCore/qdir.h>
#include <QtCore/qdebug.h>

Q_DECLARE_METATYPE(QSqlDatabase)
Q_DECLARE_METATYPE(QSqlQuery)

class QmlSqlQueryScriptClass: public QScriptClass {
public:
    QmlSqlQueryScriptClass(QScriptEngine *engine) : QScriptClass(engine)
    {
        str_length = engine->toStringHandle(QLatin1String("length"));
        str_forwardOnly = engine->toStringHandle(QLatin1String("forwardOnly")); // not in HTML5 (an optimization)
    }

    QueryFlags queryProperty(const QScriptValue &,
                             const QScriptString &name,
                             QueryFlags flags, uint *)
    {
        if (flags & HandlesReadAccess) {
            if (name == str_length) {
                return HandlesReadAccess;
            } else if (name == str_forwardOnly) {
                return flags;
            }
        }
        if (flags & HandlesWriteAccess)
            if (name == str_forwardOnly)
                return flags;
        return 0;
    }

    QScriptValue property(const QScriptValue &object,
                          const QScriptString &name, uint)
    {
        QSqlQuery query = qscriptvalue_cast<QSqlQuery>(object.data());
        if (name == str_length) {
            int s = query.size();
            if (s<0) {
                // Inefficient.
                if (query.last()) {
                    return query.at()+1;
                } else {
                    return 0;
                }
            } else {
                return s;
            }
        } else if (name == str_forwardOnly) {
            return query.isForwardOnly();
        }
        return engine()->undefinedValue();
    }

    void setProperty(QScriptValue &object,
                      const QScriptString &name, uint, const QScriptValue & value)
    {
        if (name == str_forwardOnly) {
            QSqlQuery query = qscriptvalue_cast<QSqlQuery>(object.data());
            query.setForwardOnly(value.toBool());
        }
    }

    QScriptValue::PropertyFlags propertyFlags(const QScriptValue &/*object*/, const QScriptString &name, uint /*id*/)
    {
        if (name == str_length) {
            return QScriptValue::Undeletable
                | QScriptValue::SkipInEnumeration;
        }
        return QScriptValue::Undeletable;
    }

private:
    QScriptString str_length;
    QScriptString str_forwardOnly;
};

// If the spec changes to allow iteration, check git history...
// class QmlSqlQueryScriptClassPropertyIterator : public QScriptClassPropertyIterator



enum SqlException {
    UNKNOWN_ERR,
    DATABASE_ERR,
    VERSION_ERR,
    TOO_LARGE_ERR,
    QUOTA_ERR,
    SYNTAX_ERR,
    CONSTRAINT_ERR,
    TIMEOUT_ERR
};

static const char* sqlerror[] = {
    "UNKNOWN_ERR",
    "DATABASE_ERR",
    "VERSION_ERR",
    "TOO_LARGE_ERR",
    "QUOTA_ERR",
    "SYNTAX_ERR",
    "CONSTRAINT_ERR",
    "TIMEOUT_ERR",
    0
};

#define THROW_SQL(error, desc) \
{ \
    QScriptValue errorValue = context->throwError(desc); \
    errorValue.setProperty(QLatin1String("code"), error); \
    return errorValue; \
}


static QString databaseFile(const QString& connectionName, QScriptEngine *engine)
{
    QString basename = QmlEnginePrivate::get(engine)->offlineStoragePath
                + QDir::separator() + QLatin1String("Databases") + QDir::separator();
    basename += connectionName;
    return basename;
}



static QScriptValue qmlsqldatabase_item(QScriptContext *context, QScriptEngine *engine)
{
    QSqlQuery query = qscriptvalue_cast<QSqlQuery>(context->thisObject().data());
    int i = context->argument(0).toNumber();
    if (query.at() == i || query.seek(i)) { // Qt 4.6 doesn't optimize seek(at())
        QSqlRecord r = query.record();
        QScriptValue row = engine->newObject();
        for (int j=0; j<r.count(); ++j) {
            row.setProperty(r.fieldName(j), QScriptValue(engine,r.value(j).toString()));
        }
        return row;
    }
    return engine->undefinedValue();
}

static QScriptValue qmlsqldatabase_executeSql(QScriptContext *context, QScriptEngine *engine)
{
    QSqlDatabase db = qscriptvalue_cast<QSqlDatabase>(context->thisObject());
    QString sql = context->argument(0).toString();
    QSqlQuery query(db);
    bool err = false;

    QScriptValue result;

    if (query.prepare(sql)) {
        if (context->argumentCount() > 1) {
            QScriptValue values = context->argument(1);
            if (values.isObject()) {
                for (QScriptValueIterator it(values); it.hasNext();) {
                    it.next();
                    query.bindValue(it.name(),it.value().toVariant());
                }
            } else {
                query.bindValue(0,values.toVariant());
            }
        }
        if (query.exec()) {
            result = engine->newObject();
            if (!QmlEnginePrivate::get(engine)->sqlQueryClass)
                QmlEnginePrivate::get(engine)->sqlQueryClass= new QmlSqlQueryScriptClass(engine);
            QScriptValue rows = engine->newObject(QmlEnginePrivate::get(engine)->sqlQueryClass);
            rows.setData(engine->newVariant(qVariantFromValue(query)));
            rows.setProperty(QLatin1String("item"), engine->newFunction(qmlsqldatabase_item,1), QScriptValue::SkipInEnumeration);
            result.setProperty(QLatin1String("rows"),rows);
            result.setProperty(QLatin1String("rowsAffected"),query.numRowsAffected());
            result.setProperty(QLatin1String("insertId"),query.lastInsertId().toString());
        } else {
            err = true;
        }
    } else {
        err = true;
    }
    if (err)
        THROW_SQL(DATABASE_ERR,query.lastError().text());
    return result;
}

static QScriptValue qmlsqldatabase_executeSql_readonly(QScriptContext *context, QScriptEngine *engine)
{
    QString sql = context->argument(0).toString();
    if (sql.startsWith(QLatin1String("SELECT"),Qt::CaseInsensitive)) {
        return qmlsqldatabase_executeSql(context,engine);
    } else {
        THROW_SQL(SYNTAX_ERR,QmlEngine::tr("Read-only Transaction"))
    }
}

static QScriptValue qmlsqldatabase_change_version(QScriptContext *context, QScriptEngine *engine)
{
    if (context->argumentCount() < 2)
        return engine->undefinedValue();

    QSqlDatabase db = qscriptvalue_cast<QSqlDatabase>(context->thisObject());
    QString from_version = context->argument(0).toString();
    QString to_version = context->argument(1).toString();
    QScriptValue callback = context->argument(2);

    QScriptValue instance = engine->newObject();
    instance.setProperty(QLatin1String("executeSql"), engine->newFunction(qmlsqldatabase_executeSql,1));
    QScriptValue tx = engine->newVariant(instance,qVariantFromValue(db));

    if (from_version!=context->thisObject().property(QLatin1String("version")).toString()) {
        THROW_SQL(2,QmlEngine::tr("Version mismatch"));
        return engine->undefinedValue();
    }

    bool ok = true;
    if (callback.isFunction()) {
        ok = false;
        db.transaction();
        callback.call(QScriptValue(), QScriptValueList() << tx);
        if (engine->hasUncaughtException()) {
            db.rollback();
        } else {
            if (!db.commit()) {
                db.rollback();
                THROW_SQL(0,QmlEngine::tr("SQL transaction failed"));
            } else {
                ok = true;
            }
        }
    }

    if (ok) {
        context->thisObject().setProperty(QLatin1String("version"), to_version, QScriptValue::ReadOnly);
        QSettings ini(databaseFile(db.connectionName(),engine)+QLatin1String(".ini"),QSettings::IniFormat);
        ini.setValue(QLatin1String("Version"), to_version);
    }

    return engine->undefinedValue();
}

static QScriptValue qmlsqldatabase_transaction_shared(QScriptContext *context, QScriptEngine *engine, bool readOnly)
{
    QSqlDatabase db = qscriptvalue_cast<QSqlDatabase>(context->thisObject());
    QScriptValue callback = context->argument(0);
    if (!callback.isFunction())
        THROW_SQL(UNKNOWN_ERR,QmlEngine::tr("transaction: missing callback"));

    QScriptValue instance = engine->newObject();
    instance.setProperty(QLatin1String("executeSql"),
        engine->newFunction(readOnly ? qmlsqldatabase_executeSql_readonly : qmlsqldatabase_executeSql,1));
    QScriptValue tx = engine->newVariant(instance,qVariantFromValue(db));

    db.transaction();
    callback.call(QScriptValue(), QScriptValueList() << tx);
    if (engine->hasUncaughtException()) {
        db.rollback();
    } else {
        if (!db.commit())
            db.rollback();
    }
    return engine->undefinedValue();
}

static QScriptValue qmlsqldatabase_transaction(QScriptContext *context, QScriptEngine *engine)
{
    return qmlsqldatabase_transaction_shared(context,engine,false);
}
static QScriptValue qmlsqldatabase_read_transaction(QScriptContext *context, QScriptEngine *engine)
{
    return qmlsqldatabase_transaction_shared(context,engine,true);
}

/*
    Currently documented in doc/src/declarastive/globalobject.qdoc
*/
static QScriptValue qmlsqldatabase_open_sync(QScriptContext *context, QScriptEngine *engine)
{
    QSqlDatabase database;

    QString dbname = context->argument(0).toString();
    QString dbversion = context->argument(1).toString();
    QString dbdescription = context->argument(2).toString();
    int dbestimatedsize = context->argument(3).toNumber();
    QScriptValue dbcreationCallback = context->argument(4);

    QCryptographicHash md5(QCryptographicHash::Md5);
    md5.addData(dbname.toUtf8());
    QString dbid(QLatin1String(md5.result().toHex()));

    QString basename = databaseFile(dbid,engine);
    bool created = false;
    QString version = dbversion;

    {
        QSettings ini(basename+QLatin1String(".ini"),QSettings::IniFormat);

        if (QSqlDatabase::connectionNames().contains(dbid)) {
            database = QSqlDatabase::database(dbid);
            version = ini.value(QLatin1String("Version")).toString();
            if (version != dbversion && !dbversion.isEmpty() && !version.isEmpty())
                THROW_SQL(VERSION_ERR,QmlEngine::tr("SQL: database version mismatch"));
        } else {
            created = !QFile::exists(basename+QLatin1String(".sqlite"));
            database = QSqlDatabase::addDatabase(QLatin1String("QSQLITE"), dbid);
            QDir().mkpath(basename);
            if (created) {
                ini.setValue(QLatin1String("Name"), dbname);
                if (dbcreationCallback.isFunction())
                    version = QString();
                ini.setValue(QLatin1String("Version"), version);
                ini.setValue(QLatin1String("Description"), dbdescription);
                ini.setValue(QLatin1String("EstimatedSize"), dbestimatedsize);
                ini.setValue(QLatin1String("Driver"), QLatin1String("QSQLITE"));
            } else {
                if (!dbversion.isEmpty() && ini.value(QLatin1String("Version")) != dbversion) {
                    // Incompatible
                    THROW_SQL(VERSION_ERR,QmlEngine::tr("SQL: database version mismatch"));
                }
                version = ini.value(QLatin1String("Version")).toString();
            }
            database.setDatabaseName(basename+QLatin1String(".sqlite"));
        }
        if (!database.isOpen())
            database.open();
    }

    QScriptValue instance = engine->newObject();
    instance.setProperty(QLatin1String("transaction"), engine->newFunction(qmlsqldatabase_transaction,1));
    instance.setProperty(QLatin1String("readTransaction"), engine->newFunction(qmlsqldatabase_read_transaction,1));
    instance.setProperty(QLatin1String("version"), version, QScriptValue::ReadOnly);
    instance.setProperty(QLatin1String("changeVersion"), engine->newFunction(qmlsqldatabase_change_version,3));

    QScriptValue result = engine->newVariant(instance,qVariantFromValue(database));

    if (created && dbcreationCallback.isFunction()) {
        dbcreationCallback.call(QScriptValue(), QScriptValueList() << result);
    }

    return result;
}

void qt_add_qmlsqldatabase(QScriptEngine *engine)
{
    QScriptValue openDatabase = engine->newFunction(qmlsqldatabase_open_sync, 4);
    engine->globalObject().setProperty(QLatin1String("openDatabaseSync"), openDatabase);

    QScriptValue sqlExceptionPrototype = engine->newObject();
    for (int i=0; sqlerror[i]; ++i)
        sqlExceptionPrototype.setProperty(QLatin1String(sqlerror[i]),
            i,QScriptValue::ReadOnly | QScriptValue::Undeletable | QScriptValue::SkipInEnumeration);

    engine->globalObject().setProperty(QLatin1String("SQLException"), sqlExceptionPrototype);
}

/*
HTML5 "spec" says "rs.rows[n]", but WebKit only impelments "rs.rows.item(n)". We do both (and property iterator).
We add a "forwardOnly" property that stops Qt caching results (code promises to only go forward
through the data.
*/