scriptruntime.java

java中比较著名的js引擎当属mozilla开源的rhino

                    (oldIndex > (Integer.MIN_VALUE / 10) ||
                     (oldIndex == (Integer.MIN_VALUE / 10) &&
                      c <= (negate ? -(Integer.MIN_VALUE % 10)
                                   : (Integer.MAX_VALUE % 10)))))
                {
                    return 0xFFFFFFFFL & (negate ? index : -index);
                }
            }
        }
        return -1L;
    }

    /**
     * If str is a decimal presentation of Uint32 value, return it as long.
     * Othewise return -1L;
     */
    public static long testUint32String(String str)
    {
        // The length of the decimal string representation of
        //  UINT32_MAX_VALUE, 4294967296
        final int MAX_VALUE_LENGTH = 10;

        int len = str.length();
        if (1 <= len && len <= MAX_VALUE_LENGTH) {
            int c = str.charAt(0);
            c -= '0';
            if (c == 0) {
                // Note that 00,01 etc. are not valid Uint32 presentations
                return (len == 1) ? 0L : -1L;
            }
            if (1 <= c && c <= 9) {
                long v = c;
                for (int i = 1; i != len; ++i) {
                    c = str.charAt(i) - '0';
                    if (!(0 <= c && c <= 9)) {
                        return -1;
                    }
                    v = 10 * v + c;
                }
                // Check for overflow
                if ((v >>> 32) == 0) {
                    return v;
                }
            }
        }
        return -1;
    }

    /**
     * If s represents index, then return index value wrapped as Integer
     * and othewise return s.
     */
    static Object getIndexObject(String s)
    {
        long indexTest = indexFromString(s);
        if (indexTest >= 0) {
            return new Integer((int)indexTest);
        }
        return s;
    }

    /**
     * If d is exact int value, return its value wrapped as Integer
     * and othewise return d converted to String.
     */
    static Object getIndexObject(double d)
    {
        int i = (int)d;
        if ((double)i == d) {
            return new Integer((int)i);
        }
        return toString(d);
    }

    /**
     * If toString(id) is a decimal presentation of int32 value, then id
     * is index. In this case return null and make the index available
     * as ScriptRuntime.lastIndexResult(cx). Otherwise return toString(id).
     */
    static String toStringIdOrIndex(Context cx, Object id)
    {
        if (id instanceof Number) {
            double d = ((Number)id).doubleValue();
            int index = (int)d;
            if (((double)index) == d) {
                storeIndexResult(cx, index);
                return null;
            }
            return toString(id);
        } else {
            String s;
            if (id instanceof String) {
                s = (String)id;
            } else {
                s = toString(id);
            }
            long indexTest = indexFromString(s);
            if (indexTest >= 0) {
                storeIndexResult(cx, (int)indexTest);
                return null;
            }
            return s;
        }
    }

    /**
     * Call obj.[[Get]](id)
     */
    public static Object getObjectElem(Object obj, Object elem, Context cx)
    {
        Scriptable sobj = toObjectOrNull(cx, obj);
        if (sobj == null) {
            throw undefReadError(obj, elem);
        }
        return getObjectElem(sobj, elem, cx);
    }

    public static Object getObjectElem(Scriptable obj, Object elem,
                                       Context cx)
    {
        if (obj instanceof XMLObject) {
            XMLObject xmlObject = (XMLObject)obj;
            return xmlObject.ecmaGet(cx, elem);
        }

        Object result;

        String s = toStringIdOrIndex(cx, elem);
        if (s == null) {
            int index = lastIndexResult(cx);
            result = ScriptableObject.getProperty(obj, index);
        } else {
            result = ScriptableObject.getProperty(obj, s);
        }

        if (result == Scriptable.NOT_FOUND) {
            result = Undefined.instance;
        }

        return result;
    }

    /**
     * Version of getObjectElem when elem is a valid JS identifier name.
     */
    public static Object getObjectProp(Object obj, String property,
                                       Context cx)
    {
        Scriptable sobj = toObjectOrNull(cx, obj);
        if (sobj == null) {
            throw undefReadError(obj, property);
        }
        return getObjectProp(sobj, property, cx);
    }

    public static Object getObjectProp(Scriptable obj, String property,
                                       Context cx)
    {
        if (obj instanceof XMLObject) {
            XMLObject xmlObject = (XMLObject)obj;
            return xmlObject.ecmaGet(cx, property);
        }

        Object result = ScriptableObject.getProperty(obj, property);
        if (result == Scriptable.NOT_FOUND) {
            result = Undefined.instance;
        }

        return result;
    }

    /*
     * A cheaper and less general version of the above for well-known argument
     * types.
     */
    public static Object getObjectIndex(Object obj, double dblIndex,
                                        Context cx)
    {
        Scriptable sobj = toObjectOrNull(cx, obj);
        if (sobj == null) {
            throw undefReadError(obj, toString(dblIndex));
        }

        int index = (int)dblIndex;
        if ((double)index == dblIndex) {
            return getObjectIndex(sobj, index, cx);
        } else {
            String s = toString(dblIndex);
            return getObjectProp(sobj, s, cx);
        }
    }

    public static Object getObjectIndex(Scriptable obj, int index,
                                        Context cx)
    {
        if (obj instanceof XMLObject) {
            XMLObject xmlObject = (XMLObject)obj;
            return xmlObject.ecmaGet(cx, new Integer(index));
        }

        Object result = ScriptableObject.getProperty(obj, index);
        if (result == Scriptable.NOT_FOUND) {
            result = Undefined.instance;
        }

        return result;
    }

    /*
     * Call obj.[[Put]](id, value)
     */
    public static Object setObjectElem(Object obj, Object elem, Object value,
                                       Context cx)
    {
        Scriptable sobj = toObjectOrNull(cx, obj);
        if (sobj == null) {
            throw undefWriteError(obj, elem, value);
        }
        return setObjectElem(sobj, elem, value, cx);
    }

    public static Object setObjectElem(Scriptable obj, Object elem,
                                       Object value, Context cx)
    {
        if (obj instanceof XMLObject) {
            XMLObject xmlObject = (XMLObject)obj;
            xmlObject.ecmaPut(cx, elem, value);
            return value;
        }

        String s = toStringIdOrIndex(cx, elem);
        if (s == null) {
            int index = lastIndexResult(cx);
            ScriptableObject.putProperty(obj, index, value);
        } else {
            ScriptableObject.putProperty(obj, s, value);
        }

        return value;
    }

    /**
     * Version of setObjectElem when elem is a valid JS identifier name.
     */
    public static Object setObjectProp(Object obj, String property,
                                       Object value, Context cx)
    {
        Scriptable sobj = toObjectOrNull(cx, obj);
        if (sobj == null) {
            throw undefWriteError(obj, property, value);
        }
        return setObjectProp(sobj, property, value, cx);
    }

    public static Object setObjectProp(Scriptable obj, String property,
                                       Object value, Context cx)
    {
        if (obj instanceof XMLObject) {
            XMLObject xmlObject = (XMLObject)obj;
            xmlObject.ecmaPut(cx, property, value);
        } else {
            ScriptableObject.putProperty(obj, property, value);
        }
        return value;
    }

    /*
     * A cheaper and less general version of the above for well-known argument
     * types.
     */
    public static Object setObjectIndex(Object obj, double dblIndex,
                                        Object value, Context cx)
    {
        Scriptable sobj = toObjectOrNull(cx, obj);
        if (sobj == null) {
            throw undefWriteError(obj, String.valueOf(dblIndex), value);
        }

        int index = (int)dblIndex;
        if ((double)index == dblIndex) {
            return setObjectIndex(sobj, index, value, cx);
        } else {
            String s = toString(dblIndex);
            return setObjectProp(sobj, s, value, cx);
        }
    }

    public static Object setObjectIndex(Scriptable obj, int index, Object value,
                                        Context cx)
    {
        if (obj instanceof XMLObject) {
            XMLObject xmlObject = (XMLObject)obj;
            xmlObject.ecmaPut(cx, new Integer(index), value);
        } else {
            ScriptableObject.putProperty(obj, index, value);
        }
        return value;
    }

    public static boolean deleteObjectElem(Scriptable target, Object elem,
                                           Context cx)
    {
        boolean result;
        if (target instanceof XMLObject) {
            XMLObject xmlObject = (XMLObject)target;
            result = xmlObject.ecmaDelete(cx, elem);
        } else {
            String s = toStringIdOrIndex(cx, elem);
            if (s == null) {
                int index = lastIndexResult(cx);
                result = ScriptableObject.deleteProperty(target, index);
            } else {
                result = ScriptableObject.deleteProperty(target, s);
            }
        }
        return result;
    }

    public static boolean hasObjectElem(Scriptable target, Object elem,
                                        Context cx)
    {
        boolean result;

        if (target instanceof XMLObject) {
            XMLObject xmlObject = (XMLObject)target;
            result = xmlObject.ecmaHas(cx, elem);
        } else {
            String s = toStringIdOrIndex(cx, elem);
            if (s == null) {
                int index = lastIndexResult(cx);
                result = ScriptableObject.hasProperty(target, index);
            } else {
                result = ScriptableObject.hasProperty(target, s);
            }
        }

        return result;
    }

    public static Object refGet(Ref ref, Context cx)
    {
        return ref.get(cx);
    }

    public static Object refSet(Ref ref, Object value, Context cx)
    {
        return ref.set(cx, value);
    }

    public static Object refDel(Ref ref, Context cx)
    {
        return wrapBoolean(ref.delete(cx));
    }

    static boolean isSpecialProperty(String s)
    {
        return s.equals("__proto__") || s.equals("__parent__");
    }

    public static Ref specialRef(Object obj, String specialProperty,
                                 Context cx)
    {
        return SpecialRef.createSpecial(cx, obj, specialProperty);
    }

    /**
     * The delete operator
     *
     * See ECMA 11.4.1
     *
     * In ECMA 0.19, the description of the delete operator (11.4.1)
     * assumes that the [[Delete]] method returns a value. However,
     * the definition of the [[Delete]] operator (8.6.2.5) does not
     * define a return value. Here we assume that the [[Delete]]
     * method doesn't return a value.
     */
    public static Object delete(Object obj, Object id, Context cx)
    {
        Scriptable sobj = toObjectOrNull(cx, obj);
        if (sobj == null) {
            String idStr = (id == null) ? "null" : id.toString();
            throw typeError2("msg.undef.prop.delete", toString(obj), idStr);
        }
        boolean result = deleteObjectElem(sobj, id, cx);
        return wrapBoolean(result);
    }

    /**
     * Looks up a name in the scope chain and returns its value.
     */
    public static Object name(Context cx, Scriptable scope, String name)