Merge pull request #11290 from Snuffleupagus/MessageHandler-rm-in
[MessageHandler] Re-factor and convert the code to a proper `class`
This commit is contained in:
Tim van der Meij
GitHub
commit
30ef05c161
@ -198,6 +198,7 @@
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"object-shorthand": ["error", "always", {
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"avoidQuotes": true,
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}],
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"prefer-const": "off",
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"rest-spread-spacing": ["error", "never"],
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"sort-imports": ["error", {
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"ignoreCase": true,
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@ -12,12 +12,19 @@
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/* eslint no-var: error, prefer-const: error */
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import {
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AbortException, assert, createPromiseCapability, MissingPDFException,
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ReadableStream, UnexpectedResponseException, UnknownErrorException
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} from './util';
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const CallbackKind = {
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UNKNOWN: 0,
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DATA: 1,
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ERROR: 2,
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};
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const StreamKind = {
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UNKNOWN: 0,
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CANCEL: 1,
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@ -54,50 +61,59 @@ function wrapReason(reason) {
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}
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}
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function MessageHandler(sourceName, targetName, comObj) {
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this.sourceName = sourceName;
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this.targetName = targetName;
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this.comObj = comObj;
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this.callbackId = 1;
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this.streamId = 1;
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this.postMessageTransfers = true;
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this.streamSinks = Object.create(null);
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this.streamControllers = Object.create(null);
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let callbacksCapabilities = this.callbacksCapabilities = Object.create(null);
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let ah = this.actionHandler = Object.create(null);
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class MessageHandler {
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constructor(sourceName, targetName, comObj) {
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this.sourceName = sourceName;
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this.targetName = targetName;
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this.comObj = comObj;
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this.callbackId = 1;
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this.streamId = 1;
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this.postMessageTransfers = true;
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this.streamSinks = Object.create(null);
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this.streamControllers = Object.create(null);
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this.callbackCapabilities = Object.create(null);
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this.actionHandler = Object.create(null);
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this._onComObjOnMessage = (event) => {
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let data = event.data;
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if (data.targetName !== this.sourceName) {
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return;
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}
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if (data.stream) {
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this._processStreamMessage(data);
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} else if (data.isReply) {
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let callbackId = data.callbackId;
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if (data.callbackId in callbacksCapabilities) {
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let callback = callbacksCapabilities[callbackId];
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delete callbacksCapabilities[callbackId];
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if ('reason' in data) {
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callback.reject(wrapReason(data.reason));
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} else {
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callback.resolve(data.data);
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}
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} else {
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throw new Error(`Cannot resolve callback ${callbackId}`);
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this._onComObjOnMessage = (event) => {
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const data = event.data;
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if (data.targetName !== this.sourceName) {
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return;
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}
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if (data.stream) {
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this._processStreamMessage(data);
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return;
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}
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if (data.callback) {
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const callbackId = data.callbackId;
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const capability = this.callbackCapabilities[callbackId];
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if (!capability) {
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throw new Error(`Cannot resolve callback ${callbackId}`);
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}
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delete this.callbackCapabilities[callbackId];
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if (data.callback === CallbackKind.DATA) {
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capability.resolve(data.data);
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} else if (data.callback === CallbackKind.ERROR) {
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capability.reject(wrapReason(data.reason));
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} else {
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throw new Error('Unexpected callback case');
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}
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return;
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}
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const action = this.actionHandler[data.action];
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if (!action) {
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throw new Error(`Unknown action from worker: ${data.action}`);
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}
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} else if (data.action in ah) {
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let action = ah[data.action];
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if (data.callbackId) {
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let sourceName = this.sourceName;
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let targetName = data.sourceName;
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const sourceName = this.sourceName;
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const targetName = data.sourceName;
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new Promise(function(resolve) {
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resolve(action(data.data));
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}).then(function(result) {
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comObj.postMessage({
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sourceName,
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targetName,
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isReply: true,
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callback: CallbackKind.DATA,
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callbackId: data.callbackId,
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data: result,
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});
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@ -105,31 +121,35 @@ function MessageHandler(sourceName, targetName, comObj) {
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comObj.postMessage({
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sourceName,
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targetName,
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isReply: true,
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callback: CallbackKind.ERROR,
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callbackId: data.callbackId,
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reason: wrapReason(reason),
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});
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});
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} else if (data.streamId) {
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this._createStreamSink(data);
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} else {
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action(data.data);
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return;
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}
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} else {
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throw new Error(`Unknown action from worker: ${data.action}`);
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}
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};
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comObj.addEventListener('message', this._onComObjOnMessage);
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}
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if (data.streamId) {
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this._createStreamSink(data);
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return;
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}
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action(data.data);
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};
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comObj.addEventListener('message', this._onComObjOnMessage);
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}
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MessageHandler.prototype = {
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on(actionName, handler) {
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var ah = this.actionHandler;
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if (typeof PDFJSDev === 'undefined' ||
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PDFJSDev.test('!PRODUCTION || TESTING')) {
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assert(typeof handler === 'function',
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'MessageHandler.on: Expected "handler" to be a function.');
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}
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const ah = this.actionHandler;
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if (ah[actionName]) {
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throw new Error(`There is already an actionName called "${actionName}"`);
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}
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ah[actionName] = handler;
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},
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}
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/**
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* Sends a message to the comObj to invoke the action with the supplied data.
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* @param {string} actionName - Action to call.
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@ -137,13 +157,14 @@ MessageHandler.prototype = {
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* @param {Array} [transfers] - List of transfers/ArrayBuffers.
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*/
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send(actionName, data, transfers) {
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this.postMessage({
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this._postMessage({
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sourceName: this.sourceName,
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targetName: this.targetName,
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action: actionName,
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data,
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}, transfers);
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},
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}
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/**
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* Sends a message to the comObj to invoke the action with the supplied data.
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* Expects that the other side will callback with the response.
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@ -153,11 +174,11 @@ MessageHandler.prototype = {
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* @returns {Promise} Promise to be resolved with response data.
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*/
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sendWithPromise(actionName, data, transfers) {
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var callbackId = this.callbackId++;
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var capability = createPromiseCapability();
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this.callbacksCapabilities[callbackId] = capability;
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const callbackId = this.callbackId++;
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const capability = createPromiseCapability();
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this.callbackCapabilities[callbackId] = capability;
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try {
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this.postMessage({
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this._postMessage({
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sourceName: this.sourceName,
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targetName: this.targetName,
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action: actionName,
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@ -168,7 +189,8 @@ MessageHandler.prototype = {
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capability.reject(ex);
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}
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return capability.promise;
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},
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}
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/**
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* Sends a message to the comObj to invoke the action with the supplied data.
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* Expect that the other side will callback to signal 'start_complete'.
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@ -180,14 +202,14 @@ MessageHandler.prototype = {
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* @returns {ReadableStream} ReadableStream to read data in chunks.
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*/
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sendWithStream(actionName, data, queueingStrategy, transfers) {
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let streamId = this.streamId++;
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let sourceName = this.sourceName;
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let targetName = this.targetName;
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const streamId = this.streamId++;
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const sourceName = this.sourceName;
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const targetName = this.targetName;
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const comObj = this.comObj;
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return new ReadableStream({
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start: (controller) => {
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let startCapability = createPromiseCapability();
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const startCapability = createPromiseCapability();
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this.streamControllers[streamId] = {
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controller,
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startCall: startCapability,
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@ -195,7 +217,7 @@ MessageHandler.prototype = {
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cancelCall: null,
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isClosed: false,
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};
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this.postMessage({
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this._postMessage({
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sourceName,
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targetName,
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action: actionName,
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@ -208,7 +230,7 @@ MessageHandler.prototype = {
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},
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pull: (controller) => {
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let pullCapability = createPromiseCapability();
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const pullCapability = createPromiseCapability();
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this.streamControllers[streamId].pullCall = pullCapability;
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comObj.postMessage({
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sourceName,
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@ -224,7 +246,7 @@ MessageHandler.prototype = {
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cancel: (reason) => {
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assert(reason instanceof Error, 'cancel must have a valid reason');
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let cancelCapability = createPromiseCapability();
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const cancelCapability = createPromiseCapability();
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this.streamControllers[streamId].cancelCall = cancelCapability;
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this.streamControllers[streamId].isClosed = true;
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comObj.postMessage({
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@ -238,24 +260,25 @@ MessageHandler.prototype = {
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return cancelCapability.promise;
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},
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}, queueingStrategy);
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},
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}
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/**
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* @private
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*/
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_createStreamSink(data) {
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let self = this;
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let action = this.actionHandler[data.action];
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let streamId = data.streamId;
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let desiredSize = data.desiredSize;
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let sourceName = this.sourceName;
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let targetName = data.sourceName;
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let capability = createPromiseCapability();
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const self = this;
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const action = this.actionHandler[data.action];
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const streamId = data.streamId;
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const sourceName = this.sourceName;
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const targetName = data.sourceName;
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const comObj = this.comObj;
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let streamSink = {
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const streamSink = {
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enqueue(chunk, size = 1, transfers) {
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if (this.isCancelled) {
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return;
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}
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let lastDesiredSize = this.desiredSize;
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const lastDesiredSize = this.desiredSize;
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this.desiredSize -= size;
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// Enqueue decreases the desiredSize property of sink,
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// so when it changes from positive to negative,
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@ -264,7 +287,7 @@ MessageHandler.prototype = {
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this.sinkCapability = createPromiseCapability();
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this.ready = this.sinkCapability.promise;
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}
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self.postMessage({
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self._postMessage({
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sourceName,
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targetName,
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stream: StreamKind.ENQUEUE,
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@ -302,11 +325,11 @@ MessageHandler.prototype = {
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});
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},
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sinkCapability: capability,
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sinkCapability: createPromiseCapability(),
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onPull: null,
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onCancel: null,
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isCancelled: false,
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desiredSize,
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desiredSize: data.desiredSize,
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ready: null,
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};
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@ -332,12 +355,15 @@ MessageHandler.prototype = {
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reason: wrapReason(reason),
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});
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});
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},
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}
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/**
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* @private
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*/
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_processStreamMessage(data) {
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let sourceName = this.sourceName;
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let targetName = data.sourceName;
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const streamId = data.streamId;
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const sourceName = this.sourceName;
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const targetName = data.sourceName;
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const comObj = this.comObj;
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switch (data.stream) {
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@ -465,8 +491,11 @@ MessageHandler.prototype = {
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default:
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throw new Error('Unexpected stream case');
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}
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},
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}
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/**
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* @private
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*/
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async _deleteStreamController(streamId) {
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// Delete the `streamController` only when the start, pull, and cancel
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// capabilities have settled, to prevent `TypeError`s.
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@ -478,26 +507,26 @@ MessageHandler.prototype = {
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return capability && capability.promise.catch(function() { });
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}));
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delete this.streamControllers[streamId];
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},
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}
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/**
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* Sends raw message to the comObj.
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* @private
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* @param {Object} message - Raw message.
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* @param transfers List of transfers/ArrayBuffers, or undefined.
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* @private
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*/
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postMessage(message, transfers) {
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_postMessage(message, transfers) {
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if (transfers && this.postMessageTransfers) {
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this.comObj.postMessage(message, transfers);
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} else {
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this.comObj.postMessage(message);
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}
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},
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}
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destroy() {
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this.comObj.removeEventListener('message', this._onComObjOnMessage);
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},
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};
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}
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}
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export {
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MessageHandler,
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