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Diffstat (limited to 'toolkit/modules/PromiseMessage.jsm')
-rw-r--r-- | toolkit/modules/PromiseMessage.jsm | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/toolkit/modules/PromiseMessage.jsm b/toolkit/modules/PromiseMessage.jsm new file mode 100644 index 000000000..f232d074b --- /dev/null +++ b/toolkit/modules/PromiseMessage.jsm @@ -0,0 +1,33 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public ++ * License, v. 2.0. If a copy of the MPL was not distributed with this ++ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +"use strict"; + +this.EXPORTED_SYMBOLS = ["PromiseMessage"]; + +var msgId = 0; + +var PromiseMessage = { + send(messageManager, name, data = {}) { + const id = `${name}_${msgId++}`; + + // Make a copy of data so that the caller doesn't see us setting 'id': + // To a new object, assign data's props, and then override the id. + const dataCopy = Object.assign({}, data, {id}); + + // Send the message. + messageManager.sendAsyncMessage(name, dataCopy); + + // Return a promise that resolves when we get a reply (a message of the same name). + return new Promise(resolve => { + messageManager.addMessageListener(name, function listener(reply) { + if (reply.data.id !== id) { + return; + } + messageManager.removeMessageListener(name, listener); + resolve(reply); + }); + }); + } +}; |