// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QV4FUNCTION_H
#define QV4FUNCTION_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include <qqmlprivate.h>
#include "qv4global_p.h"
#include <private/qv4executablecompilationunit_p.h>
#include <private/qv4context_p.h>
#include <private/qv4string_p.h>

namespace JSC {
class MacroAssemblerCodeRef;
}

QT_BEGIN_NAMESPACE

struct QQmlSourceLocation;

namespace QV4 {

struct Q_QML_EXPORT FunctionData
{
    WriteBarrier::HeapObjectWrapper<CompilationUnitRuntimeData, 1> compilationUnit;

    // Intentionally require an ExecutableCompilationUnit but save only a pointer to
    // CompilationUnitBase. This is so that we can take advantage of the standard layout
    // of CompilationUnitBase in the JIT. Furthermore we can safely static_cast to
    // ExecutableCompilationUnit where we need it.
    FunctionData(EngineBase *engine, ExecutableCompilationUnit *compilationUnit_);
};
// Make sure this class can be accessed through offsetof (done by the assemblers):
Q_STATIC_ASSERT(std::is_standard_layout< FunctionData >::value);

struct Q_QML_EXPORT Function : public FunctionData {
protected:
    Function(ExecutionEngine *engine, ExecutableCompilationUnit *unit,
             const CompiledData::Function *function, const QQmlPrivate::AOTCompiledFunction *aotFunction);
    ~Function();

public:
    struct JSTypedFunction {
        QVarLengthArray<QQmlType, 4> types;
    };

    struct AOTCompiledFunction {
        QVarLengthArray<QMetaType, 4> types;
    };

    QV4::ExecutableCompilationUnit *executableCompilationUnit() const
    {
        // This is safe: We require an ExecutableCompilationUnit in the ctor.
        return static_cast<QV4::ExecutableCompilationUnit *>(compilationUnit.get());
    }

    QV4::Heap::String *runtimeString(uint i) const
    {
        return compilationUnit->runtimeStrings[i];
    }

    bool call(QObject *thisObject, void **a, const QMetaType *types, int argc,
              ExecutionContext *context);
    ReturnedValue call(const Value *thisObject, const Value *argv, int argc,
                       ExecutionContext *context);

    const CompiledData::Function *compiledFunction = nullptr;
    const char *codeData = nullptr;
    JSC::MacroAssemblerCodeRef *codeRef = nullptr;

    typedef ReturnedValue (*JittedCode)(CppStackFrame *, ExecutionEngine *);
    typedef void (*AotCompiledCode)(const QQmlPrivate::AOTCompiledContext *context, void **argv);

    union {
        void *noFunction = nullptr;
        JSTypedFunction jsTypedFunction;
        AOTCompiledFunction aotCompiledFunction;
    };

    union {
        JittedCode jittedCode = nullptr;
        AotCompiledCode aotCompiledCode;
    };

    // first nArguments names in internalClass are the actual arguments
    QV4::WriteBarrier::Pointer<Heap::InternalClass> internalClass;
    int interpreterCallCount = 0;
    quint16 nFormals = 0;
    enum Kind : quint8 { JsUntyped, JsTyped, AotCompiled, Eval };
    Kind kind = JsUntyped;
    bool detectedInjectedParameters = false;

    static Function *create(ExecutionEngine *engine, ExecutableCompilationUnit *unit,
                            const CompiledData::Function *function,
                            const QQmlPrivate::AOTCompiledFunction *aotFunction);
    void destroy();

    void mark(QV4::MarkStack *ms);

    // used when dynamically assigning signal handlers (QQmlConnection)
    void updateInternalClass(ExecutionEngine *engine, const QList<QByteArray> &parameters);

    inline Heap::String *name() const {
        return runtimeString(compiledFunction->nameIndex);
    }

    static QString prettyName(const Function *function, const void *address);

    inline QString sourceFile() const { return executableCompilationUnit()->fileName(); }
    inline QUrl finalUrl() const { return executableCompilationUnit()->finalUrl(); }

    inline bool isStrict() const { return compiledFunction->flags & CompiledData::Function::IsStrict; }
    inline bool isArrowFunction() const { return compiledFunction->flags & CompiledData::Function::IsArrowFunction; }
    inline bool isGenerator() const { return compiledFunction->flags & CompiledData::Function::IsGenerator; }
    inline bool isClosureWrapper() const { return compiledFunction->flags & CompiledData::Function::IsClosureWrapper; }

    QQmlSourceLocation sourceLocation() const;

    Function *nestedFunction() const
    {
        if (compiledFunction->nestedFunctionIndex == std::numeric_limits<uint32_t>::max())
            return nullptr;
        return executableCompilationUnit()->runtimeFunctions[compiledFunction->nestedFunctionIndex];
    }

    bool isJittable() const { return kind != Function::AotCompiled && !isGenerator(); }
};

}

QT_END_NAMESPACE

#endif