C++ JSString::getChars方法代码示例

JSBool
EvalScriptVersion16(JSContext *cx, uintN argc, jsval *vp)
{
    JS_ASSERT(argc == 1);
    jsval *argv = JS_ARGV(cx, vp);
    JS_ASSERT(JSVAL_IS_STRING(argv[0]));
    JSString *str = JSVAL_TO_STRING(argv[0]);
    const jschar *chars = str->getChars(cx);
    JS_ASSERT(chars);
    size_t len = str->length();
    return callbackData->evalVersion(chars, len, JSVERSION_1_6);
}

/**
 * Handles an assertion failure in self-hosted code just like an assertion
 * failure in C++ code. Information about the failure can be provided in args[0].
 */
static bool
intrinsic_AssertionFailed(JSContext *cx, unsigned argc, Value *vp)
{
#ifdef DEBUG
    CallArgs args = CallArgsFromVp(argc, vp);
    if (args.length() > 0) {
        // try to dump the informative string
        JSString *str = ToString<CanGC>(cx, args[0]);
        if (str) {
            const jschar *chars = str->getChars(cx);
            if (chars) {
                fprintf(stderr, "Self-hosted JavaScript assertion info: ");
                JSString::dumpChars(chars, str->length());
                fputc('\n', stderr);
            }
        }
    }
#endif
    JS_ASSERT(false);
    return false;
}

//.........这里部分代码省略.........
            vp->setObject(*obj);
            if (obj->compartment() == this)
                return true;

            if (cx->runtime->preWrapObjectCallback) {
                obj = cx->runtime->preWrapObjectCallback(cx, global, obj, flags);
                if (!obj)
                    return false;
            }

            vp->setObject(*obj);
            if (obj->compartment() == this)
                return true;
        } else {
            if (cx->runtime->preWrapObjectCallback) {
                obj = cx->runtime->preWrapObjectCallback(cx, global, obj, flags);
                if (!obj)
                    return false;
            }

            JS_ASSERT(!obj->isWrapper() || obj->getClass()->ext.innerObject);
            vp->setObject(*obj);
        }

#ifdef DEBUG
        {
            JSObject *outer = obj;
            OBJ_TO_OUTER_OBJECT(cx, outer);
            JS_ASSERT(outer && outer == obj);
        }
#endif
    }

    /* If we already have a wrapper for this value, use it. */
    if (WrapperMap::Ptr p = crossCompartmentWrappers.lookup(*vp)) {
        *vp = p->value;
        if (vp->isObject()) {
            JSObject *obj = &vp->toObject();
            JS_ASSERT(obj->isCrossCompartmentWrapper());
            if (global->getClass() != &dummy_class && obj->getParent() != global) {
                do {
                    if (!obj->setParent(cx, global))
                        return false;
                    obj = obj->getProto();
                } while (obj && obj->isCrossCompartmentWrapper());
            }
        }
        return true;
    }

    if (vp->isString()) {
        Value orig = *vp;
        JSString *str = vp->toString();
        const jschar *chars = str->getChars(cx);
        if (!chars)
            return false;
        JSString *wrapped = js_NewStringCopyN(cx, chars, str->length());
        if (!wrapped)
            return false;
        vp->setString(wrapped);
        return crossCompartmentWrappers.put(orig, *vp);
    }

    JSObject *obj = &vp->toObject();

    /*
     * Recurse to wrap the prototype. Long prototype chains will run out of
     * stack, causing an error in CHECK_RECURSE.
     *
     * Wrapping the proto before creating the new wrapper and adding it to the
     * cache helps avoid leaving a bad entry in the cache on OOM. But note that
     * if we wrapped both proto and parent, we would get infinite recursion
     * here (since Object.prototype->parent->proto leads to Object.prototype
     * itself).
     */
    JSObject *proto = obj->getProto();
    if (!wrap(cx, &proto))
        return false;

    /*
     * We hand in the original wrapped object into the wrap hook to allow
     * the wrap hook to reason over what wrappers are currently applied
     * to the object.
     */
    JSObject *wrapper = cx->runtime->wrapObjectCallback(cx, obj, proto, global, flags);
    if (!wrapper)
        return false;

    vp->setObject(*wrapper);

    if (wrapper->getProto() != proto && !SetProto(cx, wrapper, proto, false))
        return false;

    if (!crossCompartmentWrappers.put(GetProxyPrivate(wrapper), *vp))
        return false;

    if (!wrapper->setParent(cx, global))
        return false;
    return true;
}

static JSBool
JO(JSContext *cx, Value *vp, StringifyContext *scx)
{
    JSObject *obj = &vp->toObject();

    CycleDetector detect(scx, obj);
    if (!detect.init(cx))
        return JS_FALSE;

    if (!scx->sb.append('{'))
        return JS_FALSE;

    Value vec[3] = { NullValue(), NullValue(), NullValue() };
    AutoArrayRooter tvr(cx, JS_ARRAY_LENGTH(vec), vec);
    Value& outputValue = vec[0];
    Value& whitelistElement = vec[1];
    AutoIdRooter idr(cx);
    jsid& id = *idr.addr();

    Value *keySource = vp;
    bool usingWhitelist = false;

    // if the replacer is an array, we use the keys from it
    if (scx->replacer && JS_IsArrayObject(cx, scx->replacer)) {
        usingWhitelist = true;
        vec[2].setObject(*scx->replacer);
        keySource = &vec[2];
    }

    JSBool memberWritten = JS_FALSE;
    AutoIdVector props(cx);
    if (!GetPropertyNames(cx, &keySource->toObject(), JSITER_OWNONLY, &props))
        return JS_FALSE;

    for (size_t i = 0, len = props.length(); i < len; i++) {
        outputValue.setUndefined();

        if (!usingWhitelist) {
            if (!js_ValueToStringId(cx, IdToValue(props[i]), &id))
                return JS_FALSE;
        } else {
            // skip non-index properties
            jsuint index = 0;
            if (!js_IdIsIndex(props[i], &index))
                continue;

            if (!scx->replacer->getProperty(cx, props[i], &whitelistElement))
                return JS_FALSE;

            if (!js_ValueToStringId(cx, whitelistElement, &id))
                return JS_FALSE;
        }

        // We should have a string id by this point. Either from 
        // JS_Enumerate's id array, or by converting an element
        // of the whitelist.
        JS_ASSERT(JSID_IS_ATOM(id));

        if (!JS_GetPropertyById(cx, obj, id, Jsvalify(&outputValue)))
            return JS_FALSE;

        if (outputValue.isObjectOrNull() && !js_TryJSON(cx, &outputValue))
            return JS_FALSE;

        // call this here, so we don't write out keys if the replacer function
        // wants to elide the value.
        if (!CallReplacerFunction(cx, id, obj, scx, &outputValue))
            return JS_FALSE;

        JSType type = JS_TypeOfValue(cx, Jsvalify(outputValue));

        // elide undefined values and functions and XML
        if (outputValue.isUndefined() || type == JSTYPE_FUNCTION || type == JSTYPE_XML)
            continue;

        // output a comma unless this is the first member to write
        if (memberWritten && !scx->sb.append(','))
            return JS_FALSE;
        memberWritten = JS_TRUE;

        if (!WriteIndent(cx, scx, scx->depth))
            return JS_FALSE;

        // Be careful below, this string is weakly rooted
        JSString *s = js_ValueToString(cx, IdToValue(id));
        if (!s)
            return JS_FALSE;

        JS::Anchor<JSString *> anchor(s);
        size_t length = s->length();
        const jschar *chars = s->getChars(cx);
        if (!chars)
            return JS_FALSE;

        if (!write_string(cx, scx->sb, chars, length) ||
            !scx->sb.append(':') ||
            !(scx->gap.empty() || scx->sb.append(' ')) ||
            !Str(cx, id, obj, scx, &outputValue, true)) {
            return JS_FALSE;
        }
//.........这里部分代码省略.........

//.........这里部分代码省略.........
        /* Translate StopIteration singleton. */
        if (obj->isStopIteration()) {
            RootedValue vvp(cx, *vp);
            bool result = js_FindClassObject(cx, JSProto_StopIteration, &vvp);
            *vp = vvp;
            return result;
        }

        /* Unwrap the object, but don't unwrap outer windows. */
        obj = UnwrapObject(&vp->toObject(), /* stopAtOuter = */ true, &flags);

        if (obj->compartment() == this)
            return WrapForSameCompartment(cx, obj, vp);

        if (cx->runtime->preWrapObjectCallback) {
            obj = cx->runtime->preWrapObjectCallback(cx, global, obj, flags);
            if (!obj)
                return false;
        }

        if (obj->compartment() == this)
            return WrapForSameCompartment(cx, obj, vp);
        vp->setObject(*obj);

#ifdef DEBUG
        {
            JSObject *outer = GetOuterObject(cx, obj);
            JS_ASSERT(outer && outer == obj);
        }
#endif
    }

    RootedValue key(cx, *vp);

    /* If we already have a wrapper for this value, use it. */
    if (WrapperMap::Ptr p = crossCompartmentWrappers.lookup(key)) {
        *vp = p->value;
        if (vp->isObject()) {
            RootedObject obj(cx, &vp->toObject());
            JS_ASSERT(obj->isCrossCompartmentWrapper());
            if (obj->getParent() != global) {
                do {
                    if (!JSObject::setParent(cx, obj, global))
                        return false;
                    obj = obj->getProto();
                } while (obj && obj->isCrossCompartmentWrapper());
            }
        }
        return true;
    }

    if (vp->isString()) {
        RootedValue orig(cx, *vp);
        JSString *str = vp->toString();
        const jschar *chars = str->getChars(cx);
        if (!chars)
            return false;
        JSString *wrapped = js_NewStringCopyN(cx, chars, str->length());
        if (!wrapped)
            return false;
        vp->setString(wrapped);
        return crossCompartmentWrappers.put(orig, *vp);
    }

    RootedObject obj(cx, &vp->toObject());

    /*
     * Recurse to wrap the prototype. Long prototype chains will run out of
     * stack, causing an error in CHECK_RECURSE.
     *
     * Wrapping the proto before creating the new wrapper and adding it to the
     * cache helps avoid leaving a bad entry in the cache on OOM. But note that
     * if we wrapped both proto and parent, we would get infinite recursion
     * here (since Object.prototype->parent->proto leads to Object.prototype
     * itself).
     */
    RootedObject proto(cx, obj->getProto());
    if (!wrap(cx, proto.address()))
        return false;

    /*
     * We hand in the original wrapped object into the wrap hook to allow
     * the wrap hook to reason over what wrappers are currently applied
     * to the object.
     */
    RootedObject wrapper(cx, cx->runtime->wrapObjectCallback(cx, obj, proto, global, flags));
    if (!wrapper)
        return false;

    // We maintain the invariant that the key in the cross-compartment wrapper
    // map is always directly wrapped by the value.
    JS_ASSERT(Wrapper::wrappedObject(wrapper) == &key.get().toObject());

    vp->setObject(*wrapper);

    if (!crossCompartmentWrappers.put(key, *vp))
        return false;

    return true;
}