qv4context_p.h

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// 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 QMLJS_ENVIRONMENT_H
#define QMLJS_ENVIRONMENT_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 "qv4global_p.h"
#include "qv4managed_p.h"
 
QT_BEGIN_NAMESPACE
 
namespace QV4 {
 
 
namespace Heap {
 
#define ExecutionContextMembers(class, Member) \
    Member(class, Pointer, ExecutionContext *, outer) \
    Member(class, Pointer, Object *, activation)
 
DECLARE_HEAP_OBJECT(ExecutionContext, Base) {
    DECLARE_MARKOBJECTS(ExecutionContext)
 
    enum ContextType {
        Type_GlobalContext = 0x1,
        Type_WithContext = 0x2,
        Type_QmlContext = 0x3,
        Type_BlockContext = 0x4,
        Type_CallContext = 0x5
    };
 
    void init(ContextType t)
    {
        Base::init();
 
        type = t;
    }
 
    const VTable *vtable() const {
        return internalClass->vtable;
    }
 
    quint32 type : 8;
    quint32 nArgs : 24;
#if QT_POINTER_SIZE == 8
    quint8 padding_[4];
#endif
};
Q_STATIC_ASSERT(std::is_trivial_v<ExecutionContext>);
Q_STATIC_ASSERT(sizeof(ExecutionContext) == sizeof(Base) + sizeof(ExecutionContextData) + QT_POINTER_SIZE);
 
Q_STATIC_ASSERT(std::is_standard_layout<ExecutionContextData>::value);
Q_STATIC_ASSERT(offsetof(ExecutionContextData, outer) == 0);
Q_STATIC_ASSERT(offsetof(ExecutionContextData, activation) == offsetof(ExecutionContextData, outer) + QT_POINTER_SIZE);
 
#define CallContextMembers(class, Member) \
    Member(class, Pointer, JavaScriptFunctionObject *, function) \
    Member(class, ValueArray, ValueArray, locals)
 
DECLARE_HEAP_OBJECT(CallContext, ExecutionContext) {
    DECLARE_MARKOBJECTS(CallContext)
 
    void init()
    {
        ExecutionContext::init(Type_CallContext);
    }
 
    int argc() const {
        return static_cast<int>(nArgs);
    }
    const Value *args() const {
        return locals.data() + locals.size;
    }
    void setArg(uint index, Value v);
 
    template <typename BlockOrFunction>
    void setupLocalTemporalDeadZone(BlockOrFunction *bof) {
        for (uint i = bof->nLocals - bof->sizeOfLocalTemporalDeadZone; i < bof->nLocals; ++i)
            locals.values[i] = Value::emptyValue();
    }
};
Q_STATIC_ASSERT(std::is_trivial_v<CallContext>);
Q_STATIC_ASSERT(std::is_standard_layout<CallContextData>::value);
Q_STATIC_ASSERT(offsetof(CallContextData, function) == 0);
//### The following size check fails on Win8. With the ValueArray at the end of the
// CallContextMembers, it doesn't look very useful.
//#if defined(Q_PROCESSOR_ARM_32) && !defined(Q_OS_IOS)
//Q_STATIC_ASSERT(sizeof(CallContext) == sizeof(ExecutionContext) + sizeof(CallContextData) + QT_POINTER_SIZE);
//#else
//Q_STATIC_ASSERT(sizeof(CallContext) == sizeof(ExecutionContext) + sizeof(CallContextData));
//#endif
 
 
}
 
struct Q_QML_EXPORT ExecutionContext : public Managed
{
    enum {
        IsExecutionContext = true
    };
 
    V4_MANAGED(ExecutionContext, Managed)
    Q_MANAGED_TYPE(ExecutionContext)
    V4_INTERNALCLASS(ExecutionContext)
 
    static Heap::CallContext *newBlockContext(QV4::CppStackFrame *frame, int blockIndex);
    static Heap::CallContext *cloneBlockContext(ExecutionEngine *engine,
                                                Heap::CallContext *callContext);
    static Heap::CallContext *newCallContext(JSTypesStackFrame *frame);
    Heap::ExecutionContext *newWithContext(Heap::Object *with) const;
    static Heap::ExecutionContext *newCatchContext(CppStackFrame *frame, int blockIndex, Heap::String *exceptionVarName);
 
    void createMutableBinding(String *name, bool deletable);
 
    enum Error {
        NoError,
        TypeError,
        RangeError
    };
 
    Error setProperty(String *name, const Value &value);
 
    ReturnedValue getProperty(String *name);
    ReturnedValue getPropertyAndBase(String *name, Value *base);
    bool deleteProperty(String *name);
 
    inline CallContext *asCallContext();
    inline const CallContext *asCallContext() const;
 
protected:
    // vtable method required for compilation
    static bool virtualDeleteProperty(Managed *, PropertyKey) {
        Q_UNREACHABLE();
    }
};
 
struct Q_QML_EXPORT CallContext : public ExecutionContext
{
    V4_MANAGED(CallContext, ExecutionContext)
    V4_INTERNALCLASS(CallContext)
 
    int argc() const {
        return d()->argc();
    }
    const Value *args() const {
        return d()->args();
    }
};
 
inline CallContext *ExecutionContext::asCallContext()
{
    return d()->type == Heap::ExecutionContext::Type_CallContext ? static_cast<CallContext *>(this) : nullptr;
}
 
inline const CallContext *ExecutionContext::asCallContext() const
{
    return d()->type == Heap::ExecutionContext::Type_CallContext ? static_cast<const CallContext *>(this) : nullptr;
}
 
} // namespace QV4
 
QT_END_NAMESPACE
 
#endif