/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * This file is part of the LibreOffice project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   Licensed to the Apache Software Foundation (ASF) under one or more

 *   contributor license agreements. See the NOTICE file distributed

 *   with this work for additional information regarding copyright

 *   ownership. The ASF licenses this file to you under the Apache

 *   License, Version 2.0 (the "License"); you may not use this file

 *   except in compliance with the License. You may obtain a copy of

 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .

 */

#pragma once

#include <rtl/ustring.hxx>

#include <com/sun/star/uno/Sequence.hxx>

#include <memory>

#include <span>

namespace com::sun::star

{

namespace beans

{

class XMultiPropertySet;

}

namespace beans

{

class XPropertySet;

}

namespace beans

{

class XPropertySetInfo;

}

}

/**

 * The MultiPropertySetHelper performs the following functions:

 *

 * Given a list of property names (as char** or OUString*), it can

 * query an XMultiPropertySet (or XPropertySet) which of these properties

 * it supports (method hasProperties(...)). The properties *MUST* be

 * sorted alphabetically.

 *

 * Then, the X(Multi)PropertySet can be queried for values, and only

 * the supported properties are queried. (method getValues(...)) The

 * values are stored in the helper itself.

 *

 * Finally, each property can be queried for existence

 * (method hasProperty(...)) or its value (method (getValue(...))).

 *

 * After some initial preparation (hasProperties, getValues) the

 * MultiPropertySetHelper can be used similarly to an

 * XPropertySet in that you can query the values in the places where you

 * need them. However, if an XMultiPropertySet is supplied, the queries

 * are more efficient, often significantly so.

 */

class MultiPropertySetHelper

{

    /// names of all properties

    std::span<const OUString> pPropertyNames;

    /// the sequence of property names that the current (multi)

    /// property set implementation supports

    css::uno::Sequence<OUString> aPropertySequence;

    /// an array of indices that maps from pPropertyNames indices to

    /// aPropertySequence indices

    std::unique_ptr<sal_Int16[]> pSequenceIndex;

    /// the last set of values retrieved by getValues

    css::uno::Sequence<css::uno::Any> aValues;

    /// result of aValues.getConstArray()

    const css::uno::Any* pValues;

    /// an empty Any

    css::uno::Any aEmptyAny;

public:

    MultiPropertySetHelper(std::span<const OUString> pNames);

    ~MultiPropertySetHelper();

    /**

     * Call hasPropertiesByName for the provided XPropertySetInfo and build

     * list of allowed properties.

     */

    void hasProperties(const css::uno::Reference<css::beans::XPropertySetInfo>&);

    /**

     * Return whether hasProperties was called

     * (i.e. if we are ready to call getValues)

     */

    bool checkedProperties();

    /**

     * Get values from the XMultiPropertySet.

     *

     * May only be called after hasProperties() was called for the

     * appropriate XPropertySetInfo.

     */

    void getValues(const css::uno::Reference<css::beans::XMultiPropertySet>&);

    /**

     * Get values from the XPropertySet. This can be much slower than

     * getValues( const Reference<XMultiPropertySet& ) and hence

     * should be avoided.

     *

     * May only be called after hasProperties() was called for the

     * appropriate XPropertySetInfo.

     */

    void getValues(const css::uno::Reference<css::beans::XPropertySet>&);

    /**

     * Get a value from the values array.

     *

     * May only be called after getValues() was called.

     */

    inline const css::uno::Any& getValue(sal_Int16 nIndex);

    /**

     * Find out if this property is supported.

     *

     * May only be called after hasProperties() was called.

     */

    inline bool hasProperty(sal_Int16 nIndex);

    /**

     * Get a value from the XPropertySet on demand.

     *

     * If neither getValues nor getValueOnDemand has been called already

     * after the last call to resetValues, the values are retrieved

     * using getValues. Otherwise the value already retrieved is returned.

     * In case XMultiPropertySet is supported by the XPropertySet and

     * bTryMult is set, the XMultiPropertySet is used to get the values.

     *

     */

    const css::uno::Any& getValue(sal_Int16 nIndex,

                                  const css::uno::Reference<css::beans::XPropertySet>&,

                                  bool bTryMulti = false);

    /**

     * Get a value from the XMultiPropertySet on demand.

     *

     * If neither getValues nor getValueOnDemand has been called already

     * after the last call to resetValues, the values are retrieved

     * using getValues. Otherwise the value already retrieved is returned.

     * In case XMultiPropertySet is supported by the XPropertySet,

     * XMultiPropertySet is used to get the values.

     *

     */

    const css::uno::Any& getValue(sal_Int16 nIndex,

                                  const css::uno::Reference<css::beans::XMultiPropertySet>&);

    void resetValues() { pValues = nullptr; }

};

// inline implementations of the often-called methods getValue and hasProperty:

const css::uno::Any& MultiPropertySetHelper::getValue(sal_Int16 nValueNo)

{

    assert(pValues && "called getValue() without calling getValues()");

    assert(pSequenceIndex && "called getValue() without calling hasProperties()");

    assert(o3tl::make_unsigned(nValueNo) < pPropertyNames.size());

    sal_Int16 nIndex = pSequenceIndex[nValueNo];

    return (nIndex != -1) ? pValues[nIndex] : aEmptyAny;

}

bool MultiPropertySetHelper::hasProperty(sal_Int16 nValueNo)

{

    assert(pSequenceIndex && "called hasProperty() without calling hasProperties()");

    assert(o3tl::make_unsigned(nValueNo) < pPropertyNames.size());

    return pSequenceIndex[nValueNo] != -1;

}

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