C++ JS_ClearPendingException函数代码示例

void
FetchStreamReader::ResolvedCallback(JSContext* aCx,
                                    JS::Handle<JS::Value> aValue)
{
  if (mStreamClosed) {
    return;
  }

  // This promise should be resolved with { done: boolean, value: something },
  // "value" is interesting only if done is false.

  // We don't want to play with JS api, let's WebIDL bindings doing it for us.
  // FetchReadableStreamReadDataDone is a dictionary with just a boolean, if the
  // parsing succeeded, we can proceed with the parsing of the "value", which it
  // must be a Uint8Array.
  FetchReadableStreamReadDataDone valueDone;
  if (!valueDone.Init(aCx, aValue)) {
    JS_ClearPendingException(aCx);
    CloseAndRelease(aCx, NS_ERROR_DOM_INVALID_STATE_ERR);
    return;
  }

  if (valueDone.mDone) {
    // Stream is completed.
    CloseAndRelease(aCx, NS_BASE_STREAM_CLOSED);
    return;
  }

  UniquePtr<FetchReadableStreamReadDataArray> value(
    new FetchReadableStreamReadDataArray);
  if (!value->Init(aCx, aValue) || !value->mValue.WasPassed()) {
    JS_ClearPendingException(aCx);
    CloseAndRelease(aCx, NS_ERROR_DOM_INVALID_STATE_ERR);
    return;
  }

  Uint8Array& array = value->mValue.Value();
  array.ComputeLengthAndData();
  uint32_t len = array.Length();

  if (len == 0) {
    // If there is nothing to read, let's do another reading.
    OnOutputStreamReady(mPipeOut);
    return;
  }

  MOZ_DIAGNOSTIC_ASSERT(!mBuffer);
  mBuffer = Move(value);

  mBufferOffset = 0;
  mBufferRemaining = len;

  nsresult rv = WriteBuffer();
  if (NS_FAILED(rv)) {
    // DOMException only understands errors from domerr.msg, so we normalize to
    // identifying an abort if the write fails.
    CloseAndRelease(aCx, NS_ERROR_DOM_ABORT_ERR);
  }
}

void
FileReader::OnLoadEndArrayBuffer()
{
  AutoJSAPI jsapi;
  if (!jsapi.Init(GetParentObject())) {
    FreeDataAndDispatchError(NS_ERROR_FAILURE);
    return;
  }

  RootResultArrayBuffer();

  JSContext* cx = jsapi.cx();

  mResultArrayBuffer = JS_NewArrayBufferWithContents(cx, mDataLen, mFileData);
  if (mResultArrayBuffer) {
    mFileData = nullptr; // Transfer ownership
    FreeDataAndDispatchSuccess();
    return;
  }

  // Let's handle the error status.

  JS::Rooted<JS::Value> exceptionValue(cx);
  if (!JS_GetPendingException(cx, &exceptionValue) ||
      // This should not really happen, exception should always be an object.
      !exceptionValue.isObject()) {
    JS_ClearPendingException(jsapi.cx());
    FreeDataAndDispatchError(NS_ERROR_OUT_OF_MEMORY);
    return;
  }

  JS_ClearPendingException(jsapi.cx());

  JS::Rooted<JSObject*> exceptionObject(cx, &exceptionValue.toObject());
  JSErrorReport* er = JS_ErrorFromException(cx, exceptionObject);
  if (!er || er->message()) {
    FreeDataAndDispatchError(NS_ERROR_OUT_OF_MEMORY);
    return;
  }

  nsAutoString errorName;
  JSFlatString* name = js::GetErrorTypeName(cx, er->exnType);
  if (name) {
    AssignJSFlatString(errorName, name);
  }

  nsAutoCString errorMsg(er->message().c_str());
  nsAutoCString errorNameC = NS_LossyConvertUTF16toASCII(errorName);
  // XXX Code selected arbitrarily
  mError =
    new DOMException(NS_ERROR_DOM_INVALID_STATE_ERR, errorMsg,
                     errorNameC, DOMException_Binding::INVALID_STATE_ERR);

  FreeDataAndDispatchError();
}

nsresult
MobileConnectionCallback::NotifySendCancelMmiSuccessWithStrings(const nsAString& aServiceCode,
                                                                const nsAString& aStatusMessage,
                                                                uint32_t aCount,
                                                                const char16_t** aAdditionalInformation)
{
  AutoJSAPI jsapi;
  if (NS_WARN_IF(!jsapi.Init(mWindow))) {
    return NS_ERROR_FAILURE;
  }

  JSContext* cx = jsapi.cx();
  RootedDictionary<MozMMIResult> result(cx);

  result.mServiceCode.Assign(aServiceCode);
  result.mStatusMessage.Assign(aStatusMessage);

  nsTArray<nsString> additionalInformation;
  for (uint32_t i = 0; i < aCount; i++) {
    additionalInformation.AppendElement(nsDependentString(aAdditionalInformation[i]));
  }

  JS::Rooted<JS::Value> jsAdditionalInformation(cx);
  if (!ToJSValue(cx, additionalInformation, &jsAdditionalInformation)) {
    JS_ClearPendingException(cx);
    return NS_ERROR_TYPE_ERR;
  }

  result.mAdditionalInformation.Construct().SetAsObject() =
    &jsAdditionalInformation.toObject();

  return NotifySendCancelMmiSuccess(result);
}

NS_IMETHODIMP
MobileConnectionCallback::NotifyGetNetworksSuccess(uint32_t aCount,
                                                   nsIMobileNetworkInfo** aNetworks)
{
  nsTArray<nsRefPtr<MobileNetworkInfo>> results;
  for (uint32_t i = 0; i < aCount; i++)
  {
    nsRefPtr<MobileNetworkInfo> networkInfo = new MobileNetworkInfo(mWindow);
    networkInfo->Update(aNetworks[i]);
    results.AppendElement(networkInfo);
  }

  AutoJSAPI jsapi;
  if (NS_WARN_IF(!jsapi.Init(mWindow))) {
    return NS_ERROR_FAILURE;
  }

  JSContext* cx = jsapi.cx();
  JS::Rooted<JS::Value> jsResult(cx);

  if (!ToJSValue(cx, results, &jsResult)) {
    JS_ClearPendingException(cx);
    return NS_ERROR_TYPE_ERR;
  }

  return NotifySuccess(jsResult);
}

void JSWindowActor::QueryHandler::ResolvedCallback(
    JSContext* aCx, JS::Handle<JS::Value> aValue) {
  if (!mActor) {
    return;
  }

  ipc::StructuredCloneData data;
  data.InitScope(JS::StructuredCloneScope::DifferentProcess);

  IgnoredErrorResult error;
  data.Write(aCx, aValue, error);
  if (NS_WARN_IF(error.Failed())) {
    // We failed to serialize the message over IPC. Report this error to the
    // console, and send a reject reply.
    nsAutoString msg;
    msg.Append(mActor->Name());
    msg.Append(':');
    msg.Append(mMessageName);
    msg.Append(NS_LITERAL_STRING(": message reply cannot be cloned."));
    nsContentUtils::LogSimpleConsoleError(msg, "chrome", false, true);

    JS_ClearPendingException(aCx);

    SendReply(aCx, JSWindowActorMessageKind::QueryReject,
              ipc::StructuredCloneData());
    return;
  }

  SendReply(aCx, JSWindowActorMessageKind::QueryResolve, std::move(data));
}

bool ScriptInterface::ParseJSON(const std::string& string_utf8, JS::MutableHandleValue out)
{
	JSAutoRequest rq(m->m_cx);
	std::wstring attrsW = wstring_from_utf8(string_utf8);
 	utf16string string(attrsW.begin(), attrsW.end());
	if (JS_ParseJSON(m->m_cx, reinterpret_cast<const jschar*>(string.c_str()), (u32)string.size(), out))
		return true;

	LOGERROR("JS_ParseJSON failed!");
	if (!JS_IsExceptionPending(m->m_cx))
		return false;

	JS::RootedValue exc(m->m_cx);
	if (!JS_GetPendingException(m->m_cx, &exc))
		return false;

	JS_ClearPendingException(m->m_cx);
	// We expect an object of type SyntaxError
	if (!exc.isObject())
		return false;

	JS::RootedValue rval(m->m_cx);
	JS::RootedObject excObj(m->m_cx, &exc.toObject());
	if (!JS_CallFunctionName(m->m_cx, excObj, "toString", JS::HandleValueArray::empty(), &rval))
		return false;

	std::wstring error;
	ScriptInterface::FromJSVal(m->m_cx, rval, error);
	LOGERROR("%s", utf8_from_wstring(error));
	return false;
}

static void
error_reporter(JSContext *ctx, const char *message, JSErrorReport *report)
{
	unsigned char *strict, *exception, *warning, *error;
	struct string msg;

	if (!init_string(&msg)) goto reported;

	strict	  = JSREPORT_IS_STRICT(report->flags) ? " strict" : "";
	exception = JSREPORT_IS_EXCEPTION(report->flags) ? " exception" : "";
	warning   = JSREPORT_IS_WARNING(report->flags) ? " warning" : "";
	error	  = !report->flags ? " error" : "";

	add_format_to_string(&msg, "A client script raised the following%s%s%s%s",
			strict, exception, warning, error);

	add_to_string(&msg, ":\n\n");
	add_to_string(&msg, message);

	if (report->linebuf && report->tokenptr) {
		int pos = report->tokenptr - report->linebuf;

		add_format_to_string(&msg, "\n\n%s\n.%*s^%*s.",
			       report->linebuf,
			       pos - 2, " ",
			       strlen(report->linebuf) - pos - 1, " ");
	}

	alert_smjs_error(msg.source);
	done_string(&msg);

reported:
	JS_ClearPendingException(ctx);
}

JSBool
gjs_move_exception(JSContext      *src_context,
                   JSContext      *dest_context)
{
    JSBool success;

    JS_BeginRequest(src_context);
    JS_BeginRequest(dest_context);

    /* NOTE: src and dest could be the same. */
    jsval exc;
    if (JS_GetPendingException(src_context, &exc)) {
        if (src_context != dest_context) {
            /* try to add the current stack of dest_context to the
             * stack trace of exc */
            try_to_chain_stack_trace(src_context, dest_context, exc);
            /* move the exception to dest_context */
            JS_SetPendingException(dest_context, exc);
            JS_ClearPendingException(src_context);
        }
        success = JS_TRUE;
    } else {
        success = JS_FALSE;
    }

    JS_EndRequest(dest_context);
    JS_EndRequest(src_context);

    return success;
}

  virtual bool
  MainThreadRun() override
  {
    AssertIsOnMainThread();

    // Initialise an AutoJSAPI with the target window.
    AutoJSAPI jsapi;
    if (NS_WARN_IF(!jsapi.Init(mBackingStore->GetParentObject()))) {
      mRv.Throw(NS_ERROR_UNEXPECTED);
      return true;
    }
    JSContext* cx = jsapi.cx();

    JS::Rooted<JS::Value> value(cx);
    if (!mObjBuffer.read(cx, &value)) {
      JS_ClearPendingException(cx);
      mRv.Throw(NS_ERROR_DOM_DATA_CLONE_ERR);
      return true;
    }

    nsRefPtr<Promise> promise = mBackingStore->Add(cx,
                                                   value,
                                                   mId,
                                                   mRevisionId,
                                                   mRv);
    promise->AppendNativeHandler(mPromiseWorkerProxy);
    return true;
  }

static JSString *
ValueToShortSource(JSContext *cx, jsval v)
{
    JSString *str;

    /* Avoid toSource bloat and fallibility for object types. */
    if (JSVAL_IS_PRIMITIVE(v)) {
        str = js_ValueToSource(cx, v);
    } else if (VALUE_IS_FUNCTION(cx, v)) {
        /*
         * XXX Avoid function decompilation bloat for now.
         */
        str = JS_GetFunctionId(JS_ValueToFunction(cx, v));
        if (!str && !(str = js_ValueToSource(cx, v))) {
            /*
             * Continue to soldier on if the function couldn't be
             * converted into a string.
             */
            JS_ClearPendingException(cx);
            str = JS_NewStringCopyZ(cx, "[unknown function]");
        }
    } else {
        /*
         * XXX Avoid toString on objects, it takes too long and uses too much
         * memory, for too many classes (see Mozilla bug 166743).
         */
        char buf[100];
        JS_snprintf(buf, sizeof buf, "[object %s]",
                    OBJ_GET_CLASS(cx, JSVAL_TO_OBJECT(v))->name);
        str = JS_NewStringCopyZ(cx, buf);
    }
    return str;
}

static void ReportException(JSContext *cx)
{
    if (JS_IsExceptionPending(cx)) {
        if (!JS_ReportPendingException(cx)) {
            JS_ClearPendingException(cx);
        }
    }
}

static JSBool
jsd_DebugErrorHook(JSContext *cx, const char *message,
                   JSErrorReport *report, void *closure)
{
    JSDContext* jsdc = (JSDContext*) closure;
    JSD_ErrorReporter errorReporter;
    void*             errorReporterData;
    
    if( ! jsdc )
    {
        JS_ASSERT(0);
        return JS_TRUE;
    }
    if( JSD_IS_DANGEROUS_THREAD(jsdc) )
        return JS_TRUE;

    /* local in case hook gets cleared on another thread */
    JSD_LOCK();
    errorReporter     = jsdc->errorReporter;
    errorReporterData = jsdc->errorReporterData;
    JSD_UNLOCK();

    if(!errorReporter)
        return JS_TRUE;

    switch(errorReporter(jsdc, cx, message, report, errorReporterData))
    {
        case JSD_ERROR_REPORTER_PASS_ALONG:
            return JS_TRUE;
        case JSD_ERROR_REPORTER_RETURN:
            return JS_FALSE;
        case JSD_ERROR_REPORTER_DEBUG:
        {
            jsval rval;
            JSD_ExecutionHookProc   hook;
            void*                   hookData;

            /* local in case hook gets cleared on another thread */
            JSD_LOCK();
            hook = jsdc->debugBreakHook;
            hookData = jsdc->debugBreakHookData;
            JSD_UNLOCK();

            jsd_CallExecutionHook(jsdc, cx, JSD_HOOK_DEBUG_REQUESTED,
                                  hook, hookData, &rval);
            /* XXX Should make this dependent on ExecutionHook retval */
            return JS_TRUE;
        }
        case JSD_ERROR_REPORTER_CLEAR_RETURN:
            if(report && JSREPORT_IS_EXCEPTION(report->flags))
                JS_ClearPendingException(cx);
            return JS_FALSE;
        default:
            JS_ASSERT(0);
            break;
    }
    return JS_TRUE;
}

bool
AutoJSAPI::StealException(JS::MutableHandle<JS::Value> aVal)
{
  if (!PeekException(aVal)) {
    return false;
  }
  JS_ClearPendingException(cx());
  return true;
}

void
AutoEntryScript::DocshellEntryMonitor::Entry(JSContext* aCx, JSFunction* aFunction,
                                             JSScript* aScript, JS::Handle<JS::Value> aAsyncStack,
                                             JS::Handle<JSString*> aAsyncCause)
{
  JS::Rooted<JSFunction*> rootedFunction(aCx);
  if (aFunction) {
    rootedFunction = aFunction;
  }
  JS::Rooted<JSScript*> rootedScript(aCx);
  if (aScript) {
    rootedScript = aScript;
  }

  nsCOMPtr<nsPIDOMWindowInner> window =
    do_QueryInterface(xpc::NativeGlobal(JS::CurrentGlobalOrNull(aCx)));
  if (!window || !window->GetDocShell() ||
      !window->GetDocShell()->GetRecordProfileTimelineMarkers()) {
    return;
  }

  nsCOMPtr<nsIDocShell> docShellForJSRunToCompletion = window->GetDocShell();
  nsString filename;
  uint32_t lineNumber = 0;

  js::AutoStableStringChars functionName(aCx);
  if (rootedFunction) {
    JS::Rooted<JSString*> displayId(aCx, JS_GetFunctionDisplayId(rootedFunction));
    if (displayId) {
      if (!functionName.initTwoByte(aCx, displayId)) {
        JS_ClearPendingException(aCx);
        return;
      }
    }
  }

  if (!rootedScript) {
    rootedScript = JS_GetFunctionScript(aCx, rootedFunction);
  }
  if (rootedScript) {
    filename = NS_ConvertUTF8toUTF16(JS_GetScriptFilename(rootedScript));
    lineNumber = JS_GetScriptBaseLineNumber(aCx, rootedScript);
  }

  if (!filename.IsEmpty() || functionName.isTwoByte()) {
    const char16_t* functionNameChars = functionName.isTwoByte() ?
      functionName.twoByteChars() : nullptr;

    JS::Rooted<JS::Value> asyncCauseValue(aCx, aAsyncCause ? StringValue(aAsyncCause) :
                                          JS::NullValue());
    docShellForJSRunToCompletion->NotifyJSRunToCompletionStart(mReason,
                                                               functionNameChars,
                                                               filename.BeginReading(),
                                                               lineNumber, aAsyncStack,
                                                               asyncCauseValue);
  }
}

RuntimeContext::~RuntimeContext()
{
	JS_SetContextThread(_context);
	JS_ClearNewbornRoots(_context);
	JS_ClearRegExpStatics(_context);
	JS_ClearPendingException(_context);
	JS_MaybeGC(_context);
	JS_DestroyContext(_context);
}