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/* 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/. */
let EXPORTED_SYMBOLS = [
"AsyncRunner",
];
const { interfaces: Ci, classes: Cc } = Components;
function AsyncRunner(callbacks) {
this._callbacks = callbacks;
this._iteratorQueue = [];
// This catches errors reported to the console, e.g., via Cu.reportError.
Cc["@mozilla.org/consoleservice;1"].
getService(Ci.nsIConsoleService).
registerListener(this);
}
AsyncRunner.prototype = {
appendIterator: function AR_appendIterator(iter) {
this._iteratorQueue.push(iter);
},
next: function AR_next(/* ... */) {
if (!this._iteratorQueue.length) {
this.destroy();
this._callbacks.done();
return;
}
// send() discards all arguments after the first, so there's no choice here
// but to send only one argument to the yielder.
let args = [arguments.length <= 1 ? arguments[0] : Array.slice(arguments)];
try {
var val = this._iteratorQueue[0].send.apply(this._iteratorQueue[0], args);
}
catch (err if err instanceof StopIteration) {
this._iteratorQueue.shift();
this.next();
return;
}
catch (err) {
this._callbacks.error(err);
}
// val is truthy => call next
// val is an iterator => prepend it to the queue and start on it
if (val) {
if (typeof(val) != "boolean")
this._iteratorQueue.unshift(val);
this.next();
}
},
destroy: function AR_destroy() {
Cc["@mozilla.org/consoleservice;1"].
getService(Ci.nsIConsoleService).
unregisterListener(this);
this.destroy = function AR_alreadyDestroyed() {};
},
observe: function AR_consoleServiceListener(msg) {
if (msg instanceof Ci.nsIScriptError)
this._callbacks.consoleError(msg);
},
};
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