jsinterp.c

来自「java script test programing source code」· C语言 代码 · 共 1,863 行 · 第 1/5 页

    fp->sp = oldsp;
    if (oldfp != fp)
        cx->fp = oldfp;

    return ok;
}

JSBool
js_InternalGetOrSet(JSContext *cx, JSObject *obj, jsid id, jsval fval,
                    JSAccessMode mode, uintN argc, jsval *argv, jsval *rval)
{
    int stackDummy;

    /*
     * js_InternalInvoke could result in another try to get or set the same id
     * again, see bug 355497.
     */
    if (!JS_CHECK_STACK_SIZE(cx, stackDummy)) {
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
                             JSMSG_OVER_RECURSED);
        return JS_FALSE;
    }
    /*
     * Check general (not object-ops/class-specific) access from the running
     * script to obj.id only if id has a scripted getter or setter that we're
     * about to invoke.  If we don't check this case, nothing else will -- no
     * other native code has the chance to check.
     *
     * Contrast this non-native (scripted) case with native getter and setter
     * accesses, where the native itself must do an access check, if security
     * policies requires it.  We make a checkAccess or checkObjectAccess call
     * back to the embedding program only in those cases where we're not going
     * to call an embedding-defined native function, getter, setter, or class
     * hook anyway.  Where we do call such a native, there's no need for the
     * engine to impose a separate access check callback on all embeddings --
     * many embeddings have no security policy at all.
     */
    JS_ASSERT(mode == JSACC_READ || mode == JSACC_WRITE);
    if (cx->runtime->checkObjectAccess &&
        VALUE_IS_FUNCTION(cx, fval) &&
        FUN_INTERPRETED((JSFunction *)
                        JS_GetPrivate(cx, JSVAL_TO_OBJECT(fval))) &&
        !cx->runtime->checkObjectAccess(cx, obj, ID_TO_VALUE(id), mode,
                                        &fval)) {
        return JS_FALSE;
    }

    return js_InternalCall(cx, obj, fval, argc, argv, rval);
}

JSBool
js_Execute(JSContext *cx, JSObject *chain, JSScript *script,
           JSStackFrame *down, uintN flags, jsval *result)
{
    JSInterpreterHook hook;
    void *hookData, *mark;
    JSStackFrame *oldfp, frame;
    JSObject *obj, *tmp;
    JSBool ok;

    hook = cx->runtime->executeHook;
    hookData = mark = NULL;
    oldfp = cx->fp;
    frame.script = script;
    if (down) {
        /* Propagate arg/var state for eval and the debugger API. */
        frame.callobj = down->callobj;
        frame.argsobj = down->argsobj;
        frame.varobj = down->varobj;
        frame.fun = down->fun;
        frame.thisp = down->thisp;
        frame.argc = down->argc;
        frame.argv = down->argv;
        frame.nvars = down->nvars;
        frame.vars = down->vars;
        frame.annotation = down->annotation;
        frame.sharpArray = down->sharpArray;
    } else {
        frame.callobj = frame.argsobj = NULL;
        obj = chain;
        if (cx->options & JSOPTION_VAROBJFIX) {
            while ((tmp = OBJ_GET_PARENT(cx, obj)) != NULL)
                obj = tmp;
        }
        frame.varobj = obj;
        frame.fun = NULL;
        frame.thisp = chain;
        frame.argc = 0;
        frame.argv = NULL;
        frame.nvars = script->numGlobalVars;
        if (frame.nvars) {
            frame.vars = js_AllocRawStack(cx, frame.nvars, &mark);
            if (!frame.vars)
                return JS_FALSE;
            memset(frame.vars, 0, frame.nvars * sizeof(jsval));
        } else {
            frame.vars = NULL;
        }
        frame.annotation = NULL;
        frame.sharpArray = NULL;
    }
    frame.rval = JSVAL_VOID;
    frame.down = down;
    frame.scopeChain = chain;
    frame.pc = NULL;
    frame.sp = oldfp ? oldfp->sp : NULL;
    frame.spbase = NULL;
    frame.sharpDepth = 0;
    frame.flags = flags;
    frame.dormantNext = NULL;
    frame.xmlNamespace = NULL;
    frame.blockChain = NULL;

    /*
     * Here we wrap the call to js_Interpret with code to (conditionally)
     * save and restore the old stack frame chain into a chain of 'dormant'
     * frame chains.  Since we are replacing cx->fp, we were running into
     * the problem that if GC was called under this frame, some of the GC
     * things associated with the old frame chain (available here only in
     * the C variable 'oldfp') were not rooted and were being collected.
     *
     * So, now we preserve the links to these 'dormant' frame chains in cx
     * before calling js_Interpret and cleanup afterwards.  The GC walks
     * these dormant chains and marks objects in the same way that it marks
     * objects in the primary cx->fp chain.
     */
    if (oldfp && oldfp != down) {
        JS_ASSERT(!oldfp->dormantNext);
        oldfp->dormantNext = cx->dormantFrameChain;
        cx->dormantFrameChain = oldfp;
    }

    cx->fp = &frame;
    if (hook)
        hookData = hook(cx, &frame, JS_TRUE, 0, cx->runtime->executeHookData);

    /*
     * Use frame.rval, not result, so the last result stays rooted across any
     * GC activations nested within this js_Interpret.
     */
    ok = js_Interpret(cx, script->code, &frame.rval);
    *result = frame.rval;

    if (hookData) {
        hook = cx->runtime->executeHook;
        if (hook)
            hook(cx, &frame, JS_FALSE, &ok, hookData);
    }
    if (mark)
        js_FreeRawStack(cx, mark);
    cx->fp = oldfp;

    if (oldfp && oldfp != down) {
        JS_ASSERT(cx->dormantFrameChain == oldfp);
        cx->dormantFrameChain = oldfp->dormantNext;
        oldfp->dormantNext = NULL;
    }

    return ok;
}

#if JS_HAS_EXPORT_IMPORT
/*
 * If id is JSVAL_VOID, import all exported properties from obj.
 */
static JSBool
ImportProperty(JSContext *cx, JSObject *obj, jsid id)
{
    JSBool ok;
    JSIdArray *ida;
    JSProperty *prop;
    JSObject *obj2, *target, *funobj, *closure;
    JSString *str;
    uintN attrs;
    jsint i;
    jsval value;

    if (JSVAL_IS_VOID(id)) {
        ida = JS_Enumerate(cx, obj);
        if (!ida)
            return JS_FALSE;
        ok = JS_TRUE;
        if (ida->length == 0)
            goto out;
    } else {
        ida = NULL;
        if (!OBJ_LOOKUP_PROPERTY(cx, obj, id, &obj2, &prop))
            return JS_FALSE;
        if (!prop) {
            str = js_DecompileValueGenerator(cx, JSDVG_IGNORE_STACK,
                                             ID_TO_VALUE(id), NULL);
            if (str)
                js_ReportIsNotDefined(cx, JS_GetStringBytes(str));
            return JS_FALSE;
        }
        ok = OBJ_GET_ATTRIBUTES(cx, obj, id, prop, &attrs);
        OBJ_DROP_PROPERTY(cx, obj2, prop);
        if (!ok)
            return JS_FALSE;
        if (!(attrs & JSPROP_EXPORTED)) {
            str = js_DecompileValueGenerator(cx, JSDVG_IGNORE_STACK,
                                             ID_TO_VALUE(id), NULL);
            if (str) {
                JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
                                     JSMSG_NOT_EXPORTED,
                                     JS_GetStringBytes(str));
            }
            return JS_FALSE;
        }
    }

    target = cx->fp->varobj;
    i = 0;
    do {
        if (ida) {
            id = ida->vector[i];
            ok = OBJ_GET_ATTRIBUTES(cx, obj, id, NULL, &attrs);
            if (!ok)
                goto out;
            if (!(attrs & JSPROP_EXPORTED))
                continue;
        }
        ok = OBJ_CHECK_ACCESS(cx, obj, id, JSACC_IMPORT, &value, &attrs);
        if (!ok)
            goto out;
        if (VALUE_IS_FUNCTION(cx, value)) {
            funobj = JSVAL_TO_OBJECT(value);
            closure = js_CloneFunctionObject(cx, funobj, obj);
            if (!closure) {
                ok = JS_FALSE;
                goto out;
            }
            value = OBJECT_TO_JSVAL(closure);
        }

        /*
         * Handle the case of importing a property that refers to a local
         * variable or formal parameter of a function activation.  These
         * properties are accessed by opcodes using stack slot numbers
         * generated by the compiler rather than runtime name-lookup.  These
         * local references, therefore, bypass the normal scope chain lookup.
         * So, instead of defining a new property in the activation object,
         * modify the existing value in the stack slot.
         */
        if (OBJ_GET_CLASS(cx, target) == &js_CallClass) {
            ok = OBJ_LOOKUP_PROPERTY(cx, target, id, &obj2, &prop);
            if (!ok)
                goto out;
        } else {
            prop = NULL;
        }
        if (prop && target == obj2) {
            ok = OBJ_SET_PROPERTY(cx, target, id, &value);
        } else {
            ok = OBJ_DEFINE_PROPERTY(cx, target, id, value, NULL, NULL,
                                     attrs & ~(JSPROP_EXPORTED |
                                               JSPROP_GETTER |
                                               JSPROP_SETTER),
                                     NULL);
        }
        if (prop)
            OBJ_DROP_PROPERTY(cx, obj2, prop);
        if (!ok)
            goto out;
    } while (ida && ++i < ida->length);

out:
    if (ida)
        JS_DestroyIdArray(cx, ida);
    return ok;
}
#endif /* JS_HAS_EXPORT_IMPORT */

JSBool
js_CheckRedeclaration(JSContext *cx, JSObject *obj, jsid id, uintN attrs,
                      JSObject **objp, JSProperty **propp)
{
    JSObject *obj2;
    JSProperty *prop;
    uintN oldAttrs, report;
    JSBool isFunction;
    jsval value;
    const char *type, *name;

    if (!OBJ_LOOKUP_PROPERTY(cx, obj, id, &obj2, &prop))
        return JS_FALSE;
    if (propp) {
        *objp = obj2;
        *propp = prop;
    }
    if (!prop)
        return JS_TRUE;

    /*
     * Use prop as a speedup hint to OBJ_GET_ATTRIBUTES, but drop it on error.
     * An assertion at label bad: will insist that it is null.
     */
    if (!OBJ_GET_ATTRIBUTES(cx, obj2, id, prop, &oldAttrs)) {
        OBJ_DROP_PROPERTY(cx, obj2, prop);
#ifdef DEBUG
        prop = NULL;
#endif
        goto bad;
    }

    /*
     * From here, return true, or else goto bad on failure to null out params.
     * If our caller doesn't want prop, drop it (we don't need it any longer).
     */
    if (!propp) {
        OBJ_DROP_PROPERTY(cx, obj2, prop);
        prop = NULL;
    }

    /* If either property is readonly, we have an error. */
    report = ((oldAttrs | attrs) & JSPROP_READONLY)
             ? JSREPORT_ERROR
             : JSREPORT_WARNING | JSREPORT_STRICT;

    if (report != JSREPORT_ERROR) {
        /*
         * Allow redeclaration of variables and functions, but insist that the
         * new value is not a getter if the old value was, ditto for setters --
         * unless prop is impermanent (in which case anyone could delete it and
         * redefine it, willy-nilly).
         */
        if (!(attrs & (JSPROP_GETTER | JSPROP_SETTER)))
            return JS_TRUE;
        if ((~(oldAttrs ^ attrs) & (JSPROP_GETTER | JSPROP_SETTER)) == 0)
            return JS_TRUE;
        if (!(oldAttrs & JSPROP_PERMANENT))
            return JS_TRUE;
        report = JSREPORT_ERROR;
    }

    isFunction = (oldAttrs & (JSPROP_GETTER | JSPROP_SETTER)) != 0;
    if (!isFunction) {
        if (!OBJ_GET_PROPERTY(cx, obj, id, &value))
            goto bad;
        isFunction = VALUE_IS_FUNCTION(cx, value);
    }
    type = (oldAttrs & attrs & JSPROP_GETTER)
           ? js_getter_str
           : (oldAttrs & attrs & JSPROP_SETTER)
           ? js_setter_str
           : (oldAttrs & JSPROP_READONLY)
           ? js_const_str
           : isFunction
           ? js_function_str
           : js_var_str;
    name = js_AtomToPrintableString(cx, JSID_TO_ATOM(id));
    if (!name)
        goto bad;
    return JS_ReportErrorFlagsAndNumber(cx, report,
                                        js_GetErrorMessage, NULL,
                                        JSMSG_REDECLARED_VAR,
                                        type, name);

bad:
    if (propp) {
        *objp = NULL;
        *propp = NULL;
    }
    JS_ASSERT(!prop);
    return JS_FALSE;
}

JSBool
js_StrictlyEqual(jsval lval, jsval rval)
{
    jsval ltag = JSVAL_TAG(lval), rt