jsfun.c

一个基于alice开发的机器人

        if (slot < JS_MAX(fp->argc, fp->fun->nargs) &&
            !ArgWasDeleted(cx, fp, slot)) {
            /* XXX ECMA specs DontEnum, contrary to other array-like objects */
            if (!js_DefineProperty(cx, obj, (jsid) id, fp->argv[slot],
                                   args_getProperty, args_setProperty,
                                   JSVERSION_IS_ECMA(cx->version)
                                   ? 0
                                   : JSPROP_ENUMERATE,
                                   NULL)) {
                return JS_FALSE;
            }
            *objp = obj;
        }
    } else {
        str = JSVAL_TO_STRING(id);
        atom = cx->runtime->atomState.lengthAtom;
        if (str == ATOM_TO_STRING(atom)) {
            tinyid = ARGS_LENGTH;
            value = INT_TO_JSVAL(fp->argc);
        } else {
            atom = cx->runtime->atomState.calleeAtom;
            if (str == ATOM_TO_STRING(atom)) {
                tinyid = ARGS_CALLEE;
                value = fp->argv ? fp->argv[-2]
                                 : OBJECT_TO_JSVAL(fp->fun->object);
            } else {
                atom = NULL;

                /* Quell GCC overwarnings. */
                tinyid = 0;
                value = JSVAL_NULL;
            }
        }

        if (atom && !TEST_OVERRIDE_BIT(fp, tinyid)) {
            if (!js_DefineNativeProperty(cx, obj, (jsid) atom, value,
                                         args_getProperty, args_setProperty, 0,
                                         SPROP_HAS_SHORTID, tinyid, NULL)) {
                return JS_FALSE;
            }
            *objp = obj;
        }
    }

    return JS_TRUE;
}

static JSBool
args_enumerate(JSContext *cx, JSObject *obj)
{
    JSStackFrame *fp;
    JSObject *pobj;
    JSProperty *prop;
    uintN slot, nargs;

    fp = (JSStackFrame *)
         JS_GetInstancePrivate(cx, obj, &js_ArgumentsClass, NULL);
    if (!fp)
        return JS_TRUE;
    JS_ASSERT(fp->argsobj);
    JS_ASSERT(fp->fun);

    /*
     * Trigger reflection with value snapshot in args_resolve using a series
     * of js_LookupProperty calls.  We handle length, callee, and the indexed
     * argument properties.  We know that args_resolve covers all these cases
     * and creates direct properties of obj, but that it may fail to resolve
     * length or callee if overridden.
     */
    if (!js_LookupProperty(cx, obj, (jsid) cx->runtime->atomState.lengthAtom,
                           &pobj, &prop)) {
        return JS_FALSE;
    }
    if (prop)
        OBJ_DROP_PROPERTY(cx, pobj, prop);

    if (!js_LookupProperty(cx, obj, (jsid) cx->runtime->atomState.calleeAtom,
                           &pobj, &prop)) {
        return JS_FALSE;
    }
    if (prop)
        OBJ_DROP_PROPERTY(cx, pobj, prop);

    nargs = JS_MAX(fp->argc, fp->fun->nargs);
    for (slot = 0; slot < nargs; slot++) {
        if (!js_LookupProperty(cx, obj, (jsid) INT_TO_JSVAL((jsint)slot),
                               &pobj, &prop)) {
            return JS_FALSE;
        }
        if (prop)
            OBJ_DROP_PROPERTY(cx, pobj, prop);
    }
    return JS_TRUE;
}

/*
 * The Arguments class is not initialized via JS_InitClass, and must not be,
 * because its name is "Object".  Per ECMA, that causes instances of it to
 * delegate to the object named by Object.prototype.  It also ensures that
 * arguments.toString() returns "[object Object]".
 *
 * The JSClass functions below collaborate to lazily reflect and synchronize
 * actual argument values, argument count, and callee function object stored
 * in a JSStackFrame with their corresponding property values in the frame's
 * arguments object.
 */
JSClass js_ArgumentsClass = {
    js_Object_str,
    JSCLASS_HAS_PRIVATE | JSCLASS_NEW_RESOLVE | JSCLASS_HAS_RESERVED_SLOTS(1),
    JS_PropertyStub,  args_delProperty,
    args_getProperty, args_setProperty,
    args_enumerate,   (JSResolveOp) args_resolve,
    JS_ConvertStub,   JS_FinalizeStub,
    JSCLASS_NO_OPTIONAL_MEMBERS
};

#endif /* JS_HAS_ARGS_OBJECT */

#if JS_HAS_CALL_OBJECT

JSObject *
js_GetCallObject(JSContext *cx, JSStackFrame *fp, JSObject *parent)
{
    JSObject *callobj, *funobj;

    /* Create a call object for fp only if it lacks one. */
    JS_ASSERT(fp->fun);
    callobj = fp->callobj;
    if (callobj)
        return callobj;
    JS_ASSERT(fp->fun);

    /* The default call parent is its function's parent (static link). */
    if (!parent) {
        funobj = fp->argv ? JSVAL_TO_OBJECT(fp->argv[-2]) : fp->fun->object;
        if (funobj)
            parent = OBJ_GET_PARENT(cx, funobj);
    }

    /* Create the call object and link it to its stack frame. */
    callobj = js_NewObject(cx, &js_CallClass, NULL, parent);
    if (!callobj || !JS_SetPrivate(cx, callobj, fp)) {
        cx->newborn[GCX_OBJECT] = NULL;
        return NULL;
    }
    fp->callobj = callobj;

    /* Make callobj be the scope chain and the variables object. */
    fp->scopeChain = callobj;
    fp->varobj = callobj;
    return callobj;
}

static JSBool
call_enumerate(JSContext *cx, JSObject *obj);

JSBool
js_PutCallObject(JSContext *cx, JSStackFrame *fp)
{
    JSObject *callobj;
    JSBool ok;
    jsid argsid;
    jsval aval;

    /*
     * Reuse call_enumerate here to reflect all actual args and vars into the
     * call object from fp.
     */
    callobj = fp->callobj;
    if (!callobj)
        return JS_TRUE;
    ok = call_enumerate(cx, callobj);

    /*
     * Get the arguments object to snapshot fp's actual argument values.
     */
    if (fp->argsobj) {
        argsid = (jsid) cx->runtime->atomState.argumentsAtom;
        ok &= js_GetProperty(cx, callobj, argsid, &aval);
        ok &= js_SetProperty(cx, callobj, argsid, &aval);
        ok &= js_PutArgsObject(cx, fp);
    }

    /*
     * Clear the private pointer to fp, which is about to go away (js_Invoke).
     * Do this last because the call_enumerate and js_GetProperty calls above
     * need to follow the private slot to find fp.
     */
    ok &= JS_SetPrivate(cx, callobj, NULL);
    fp->callobj = NULL;
    return ok;
}

static JSPropertySpec call_props[] = {
    {js_arguments_str,  CALL_ARGUMENTS, JSPROP_PERMANENT,0,0},
    {"__callee__",      CALL_CALLEE,    0,0,0},
    {0,0,0,0,0}
};

static JSBool
call_getProperty(JSContext *cx, JSObject *obj, jsval id, jsval *vp)
{
    JSStackFrame *fp;
    jsint slot;

    if (!JSVAL_IS_INT(id))
        return JS_TRUE;
    fp = (JSStackFrame *) JS_GetPrivate(cx, obj);
    if (!fp)
        return JS_TRUE;
    JS_ASSERT(fp->fun);

    slot = JSVAL_TO_INT(id);
    switch (slot) {
      case CALL_ARGUMENTS:
        if (!TEST_OVERRIDE_BIT(fp, slot)) {
            JSObject *argsobj = js_GetArgsObject(cx, fp);
            if (!argsobj)
                return JS_FALSE;
            *vp = OBJECT_TO_JSVAL(argsobj);
        }
        break;

      case CALL_CALLEE:
        if (!TEST_OVERRIDE_BIT(fp, slot))
            *vp = fp->argv ? fp->argv[-2] : OBJECT_TO_JSVAL(fp->fun->object);
        break;

      default:
        if ((uintN)slot < JS_MAX(fp->argc, fp->fun->nargs))
            *vp = fp->argv[slot];
        break;
    }
    return JS_TRUE;
}

static JSBool
call_setProperty(JSContext *cx, JSObject *obj, jsval id, jsval *vp)
{
    JSStackFrame *fp;
    jsint slot;

    if (!JSVAL_IS_INT(id))
        return JS_TRUE;
    fp = (JSStackFrame *) JS_GetPrivate(cx, obj);
    if (!fp)
        return JS_TRUE;
    JS_ASSERT(fp->fun);

    slot = JSVAL_TO_INT(id);
    switch (slot) {
      case CALL_ARGUMENTS:
      case CALL_CALLEE:
        SET_OVERRIDE_BIT(fp, slot);
        break;

      default:
        if ((uintN)slot < JS_MAX(fp->argc, fp->fun->nargs))
            fp->argv[slot] = *vp;
        break;
    }
    return JS_TRUE;
}

JSBool
js_GetCallVariable(JSContext *cx, JSObject *obj, jsval id, jsval *vp)
{
    JSStackFrame *fp;

    JS_ASSERT(JSVAL_IS_INT(id));
    fp = (JSStackFrame *) JS_GetPrivate(cx, obj);
    if (fp) {
        /* XXX no jsint slot commoning here to avoid MSVC1.52 crashes */
        if ((uintN)JSVAL_TO_INT(id) < fp->nvars)
            *vp = fp->vars[JSVAL_TO_INT(id)];
    }
    return JS_TRUE;
}

JSBool
js_SetCallVariable(JSContext *cx, JSObject *obj, jsval id, jsval *vp)
{
    JSStackFrame *fp;

    JS_ASSERT(JSVAL_IS_INT(id));
    fp = (JSStackFrame *) JS_GetPrivate(cx, obj);
    if (fp) {
        /* XXX jsint slot is block-local here to avoid MSVC1.52 crashes */
        jsint slot = JSVAL_TO_INT(id);
        if ((uintN)slot < fp->nvars)
            fp->vars[slot] = *vp;
    }
    return JS_TRUE;
}

static JSBool
call_enumerate(JSContext *cx, JSObject *obj)
{
    JSStackFrame *fp;
    JSObject *funobj;
    JSScope *scope;
    JSScopeProperty *sprop, *cprop;
    JSPropertyOp getter;
    jsval *vec;
    JSProperty *prop;

    fp = (JSStackFrame *) JS_GetPrivate(cx, obj);
    if (!fp)
        return JS_TRUE;

    /*
     * Do not enumerate a cloned function object at fp->argv[-2], it may have
     * gained its own (mutable) scope (e.g., a brutally-shared XUL script sets
     * the clone's prototype property).  We must enumerate the function object
     * that was decorated with parameter and local variable properties by the
     * compiler when the compiler created fp->fun, namely fp->fun->object.
     *
     * Contrast with call_resolve, where we prefer fp->argv[-2], because we'll
     * use js_LookupProperty to find any overridden properties in that object,
     * if it was a mutated clone; and if not, we will search its prototype,
     * fp->fun->object, to find compiler-created params and locals.
     */
    funobj = fp->fun->object;
    if (!funobj)
        return JS_TRUE;

    /*
     * Reflect actual args from fp->argv for formal parameters, and local vars
     * and functions in fp->vars for declared variables and nested-at-top-level
     * local functions.
     */
    scope = OBJ_SCOPE(funobj);
    for (sprop = SCOPE_LAST_PROP(scope); sprop; sprop = sprop->parent) {
        getter = sprop->getter;
        if (getter == js_GetArgument)
            vec = fp->argv;
        else if (getter == js_GetLocalVariable)
            vec = fp->vars;
        else
            continue;

        /* Trigger reflection in call_resolve by doing a lookup. */
        if (!js_LookupProperty(cx, obj, sprop->id, &obj, &prop))
            return JS_FALSE;
        JS_ASSERT(obj && prop);
        cprop = (JSScopeProperty *)prop;
        LOCKED_OBJ_SET_SLOT(obj, cprop->slot, vec[sprop->shortid]);
        OBJ_DROP_PROPERTY(cx, obj, prop);
    }

    return JS_TRUE;
}

static JSBool
call_resolve(JSContext *cx, JSObject *obj, jsval id, uintN flags,
             JSObject **objp)
{
    JSStackFrame *fp;
    JSObject *funobj;
    JSString *str;
    JSAtom *atom;
    JSObject *obj2;
    JSScopeProperty *sprop;
    jsid propid;
    JSPropertyOp getter, setter;
    uintN attrs, slot, nslots, spflags;
    jsval *vp, value;
    intN shortid;

    fp = (JSStackFrame *) JS_GetPrivate(cx, obj);
    if (!fp)
        return JS_TRUE;
    JS_ASSERT(fp->fun);

    if (!JSVAL_IS_STRING(id))
        return JS_TRUE;

    funobj = fp->argv ? JSVAL_TO_OBJECT(fp->argv[-2]) : fp->fun->object;
    if (!funobj)
        return JS_TRUE;

    str = JSVAL_TO_STRING(id);
    atom = js_AtomizeString(cx, str, 0);
    if (!atom)
        return JS_FALSE;
    if (!js_LookupProperty(cx, funobj, (jsid)atom, &obj2,
                           (JSProperty **)&sprop)) {
        return JS_FALSE;
    }

    if (sprop && OBJ_IS_NATIVE(obj2)) {
        propid = sprop->id;
        getter = sprop->getter;
        attrs = sprop->attrs & ~JSPROP_SHARED;
        slot = (uintN) sprop->shortid;
        OBJ_DROP_PROPERTY(cx, obj2, (JSProperty *)sprop);
        if (getter == js_GetArgument || getter == js_GetLocalVariable) {
            if (getter == js_GetArgument) {
                vp = fp->argv;
                nslots = JS_MAX(fp->argc, fp->fun->nargs);
                getter = setter = NULL;
            } else {
                vp = fp->vars;
                nslots = fp->nvars;
                getter = js_GetCallVariable;
                setter = js_SetCallVariable;
            }
            if (slot < nslots) {