/****************************************************************************
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** This file is part of Qbs.
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
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****************************************************************************/

#ifndef QBS_EVALUATOR_H
#define QBS_EVALUATOR_H

#include "forward_decls.h"
#include "itemobserver.h"
#include "qualifiedid.h"

#include <QHash>
#include <QScriptValue>

namespace qbs {
namespace Internal {
class EvaluatorScriptClass;
class FileTags;
class Logger;
class ScriptEngine;

class Evaluator : private ItemObserver
{
    friend class SVConverter;

public:
    Evaluator(ScriptEngine *scriptEngine, Logger &logger);
    virtual ~Evaluator();

    ScriptEngine *engine() const { return m_scriptEngine; }
    QScriptValue property(const Item *item, const QString &name);

    QScriptValue value(const Item *item, const QString &name, bool *propertySet = 0);
    bool boolValue(const Item *item, const QString &name, bool defaultValue = false,
                   bool *propertyWasSet = 0);
    FileTags fileTagsValue(const Item *item, const QString &name, bool *propertySet = 0);
    QString stringValue(const Item *item, const QString &name,
                        const QString &defaultValue = QString(), bool *propertyWasSet = 0);
    QStringList stringListValue(const Item *item, const QString &name, bool *propertyWasSet = 0);

    QScriptValue scriptValue(const Item *item);
    QScriptValue fileScope(const FileContextConstPtr &file);
    QScriptValue importScope(const FileContextConstPtr &file);

    void setCachingEnabled(bool enabled);

    PropertyDependencies propertyDependencies() const;
    void clearPropertyDependencies();

    void handleEvaluationError(const Item *item, const QString &name,
            const QScriptValue &scriptValue);
private:
    void onItemPropertyChanged(Item *item);
    void onItemDestroyed(Item *item);
    bool evaluateProperty(QScriptValue *result, const Item *item, const QString &name,
            bool *propertyWasSet);

    ScriptEngine *m_scriptEngine;
    EvaluatorScriptClass *m_scriptClass;
    mutable QHash<const Item *, QScriptValue> m_scriptValueMap;
    mutable QHash<FileContextConstPtr, QScriptValue> m_fileScopeMap;
    mutable QHash<FileContextConstPtr, QScriptValue> m_importScopeMap;
};

class EvalCacheEnabler
{
public:
    EvalCacheEnabler(Evaluator *evaluator) : m_evaluator(evaluator)
    {
        m_evaluator->setCachingEnabled(true);
    }

    ~EvalCacheEnabler() { m_evaluator->setCachingEnabled(false); }

private:
    Evaluator * const m_evaluator;
};

} // namespace Internal
} // namespace qbs

#endif // QBS_EVALUATOR_H
