C++ JSString::ensureFlat方法代码示例

/* |callee| requires a usage string provided by JS_DefineFunctionsWithHelp. */
void
js::ReportUsageError(JSContext *cx, HandleObject callee, const char *msg)
{
    const char *usageStr = "usage";
    PropertyName *usageAtom = Atomize(cx, usageStr, strlen(usageStr))->asPropertyName();
    RootedId id(cx, NameToId(usageAtom));
    DebugOnly<Shape *> shape = static_cast<Shape *>(callee->as<NativeObject>().lookup(cx, id));
    MOZ_ASSERT(!shape->configurable());
    MOZ_ASSERT(!shape->writable());
    MOZ_ASSERT(shape->hasDefaultGetter());

    RootedValue usage(cx);
    if (!JS_LookupProperty(cx, callee, "usage", &usage))
        return;

    if (usage.isUndefined()) {
        JS_ReportError(cx, "%s", msg);
    } else {
        JSString *str = usage.toString();
        if (!str->ensureFlat(cx))
            return;
        AutoStableStringChars chars(cx);
        if (!chars.initTwoByte(cx, str))
            return;

        JS_ReportError(cx, "%s. Usage: %hs", msg, chars.twoByteRange().start().get());
    }
}

bool
SecurityWrapper<Base>::defineProperty(JSContext *cx, HandleObject wrapper,
                                      HandleId id, MutableHandle<PropertyDescriptor> desc) const
{
    if (desc.getter() || desc.setter()) {
        JSString *str = IdToString(cx, id);
        AutoStableStringChars chars(cx);
        const jschar *prop = nullptr;
        if (str->ensureFlat(cx) && chars.initTwoByte(cx, str))
            prop = chars.twoByteChars();
        JS_ReportErrorNumberUC(cx, js_GetErrorMessage, nullptr,
                               JSMSG_ACCESSOR_DEF_DENIED, prop);
        return false;
    }

    return Base::defineProperty(cx, wrapper, id, desc);
}

void
js::AutoEnterPolicy::reportErrorIfExceptionIsNotPending(JSContext *cx, jsid id)
{
    if (JS_IsExceptionPending(cx))
        return;

    if (JSID_IS_VOID(id)) {
        JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr,
                             JSMSG_OBJECT_ACCESS_DENIED);
    } else {
        JSString *str = IdToString(cx, id);
        AutoStableStringChars chars(cx);
        const char16_t *prop = nullptr;
        if (str->ensureFlat(cx) && chars.initTwoByte(cx, str))
            prop = chars.twoByteChars();

        JS_ReportErrorNumberUC(cx, js_GetErrorMessage, nullptr, JSMSG_PROPERTY_ACCESS_DENIED,
                               prop);
    }
}

bool
SecurityWrapper<Base>::defineProperty(JSContext *cx, HandleObject wrapper,
                                      HandleId id, MutableHandle<PropertyDescriptor> desc,
                                      ObjectOpResult &result) const
{
    if (desc.getter() || desc.setter()) {
        RootedValue idVal(cx, IdToValue(id));
        JSString *str = ValueToSource(cx, idVal);
        if (!str)
            return false;
        AutoStableStringChars chars(cx);
        const char16_t *prop = nullptr;
        if (str->ensureFlat(cx) && chars.initTwoByte(cx, str))
            prop = chars.twoByteChars();
        JS_ReportErrorNumberUC(cx, GetErrorMessage, nullptr,
                               JSMSG_ACCESSOR_DEF_DENIED, prop);
        return false;
    }

    return Base::defineProperty(cx, wrapper, id, desc, result);
}

void
js::AutoEnterPolicy::reportErrorIfExceptionIsNotPending(JSContext* cx, jsid id)
{
    if (JS_IsExceptionPending(cx))
        return;

    if (JSID_IS_VOID(id)) {
        ReportAccessDenied(cx);
    } else {
        RootedValue idVal(cx, IdToValue(id));
        JSString* str = ValueToSource(cx, idVal);
        if (!str) {
            return;
        }
        AutoStableStringChars chars(cx);
        const char16_t* prop = nullptr;
        if (str->ensureFlat(cx) && chars.initTwoByte(cx, str))
            prop = chars.twoByteChars();

        JS_ReportErrorNumberUC(cx, GetErrorMessage, nullptr, JSMSG_PROPERTY_ACCESS_DENIED,
                               prop);
    }
}

static bool
InvokeInterruptCallback(JSContext* cx)
{
    MOZ_ASSERT(cx->runtime()->requestDepth >= 1);

    cx->runtime()->gc.gcIfRequested();

    // A worker thread may have requested an interrupt after finishing an Ion
    // compilation.
    jit::AttachFinishedCompilations(cx);

    // Important: Additional callbacks can occur inside the callback handler
    // if it re-enters the JS engine. The embedding must ensure that the
    // callback is disconnected before attempting such re-entry.
    JSInterruptCallback cb = cx->runtime()->interruptCallback;
    if (!cb)
        return true;

    if (cb(cx)) {
        // Debugger treats invoking the interrupt callback as a "step", so
        // invoke the onStep handler.
        if (cx->compartment()->isDebuggee()) {
            ScriptFrameIter iter(cx);
            if (!iter.done() && iter.script()->stepModeEnabled()) {
                RootedValue rval(cx);
                switch (Debugger::onSingleStep(cx, &rval)) {
                  case JSTRAP_ERROR:
                    return false;
                  case JSTRAP_CONTINUE:
                    return true;
                  case JSTRAP_RETURN:
                    // See note in Debugger::propagateForcedReturn.
                    Debugger::propagateForcedReturn(cx, iter.abstractFramePtr(), rval);
                    return false;
                  case JSTRAP_THROW:
                    cx->setPendingException(rval);
                    return false;
                  default:;
                }
            }
        }

        return true;
    }

    // No need to set aside any pending exception here: ComputeStackString
    // already does that.
    JSString* stack = ComputeStackString(cx);
    JSFlatString* flat = stack ? stack->ensureFlat(cx) : nullptr;

    const char16_t* chars;
    AutoStableStringChars stableChars(cx);
    if (flat && stableChars.initTwoByte(cx, flat))
        chars = stableChars.twoByteRange().start().get();
    else
        chars = MOZ_UTF16("(stack not available)");
    JS_ReportErrorFlagsAndNumberUC(cx, JSREPORT_WARNING, GetErrorMessage, nullptr,
                                   JSMSG_TERMINATED, chars);

    return false;
}