yomichan/ext/fg/js/frontend-api-sender.js

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/*
* Copyright (C) 2019-2020 Yomichan Authors
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
class FrontendApiSender {
constructor() {
this._senderId = yomichan.generateId(16);
this._ackTimeout = 3000; // 3 seconds
this._responseTimeout = 10000; // 10 seconds
this._callbacks = new Map();
this._disconnected = false;
this._nextId = 0;
this._port = null;
}
invoke(action, params, target) {
if (this._disconnected) {
// attempt to reconnect the next time
this._disconnected = false;
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return Promise.reject(new Error('Disconnected'));
}
if (this._port === null) {
this._createPort();
}
const id = `${this._nextId}`;
++this._nextId;
return new Promise((resolve, reject) => {
const info = {id, resolve, reject, ack: false, timer: null};
this._callbacks.set(id, info);
info.timer = setTimeout(() => this._onError(id, 'Timeout (ack)'), this._ackTimeout);
this._port.postMessage({id, action, params, target, senderId: this._senderId});
});
}
_createPort() {
this._port = chrome.runtime.connect(null, {name: 'backend-api-forwarder'});
this._port.onDisconnect.addListener(this._onDisconnect.bind(this));
this._port.onMessage.addListener(this._onMessage.bind(this));
}
_onMessage({type, id, data, senderId}) {
if (senderId !== this._senderId) { return; }
switch (type) {
case 'ack':
this._onAck(id);
break;
case 'result':
this._onResult(id, data);
break;
}
}
_onDisconnect() {
this._disconnected = true;
this._port = null;
for (const id of this._callbacks.keys()) {
this._onError(id, 'Disconnected');
}
}
_onAck(id) {
const info = this._callbacks.get(id);
if (typeof info === 'undefined') {
yomichan.logWarning(new Error(`ID ${id} not found for ack`));
return;
}
if (info.ack) {
yomichan.logWarning(new Error(`Request ${id} already ack'd`));
return;
}
info.ack = true;
clearTimeout(info.timer);
info.timer = setTimeout(() => this._onError(id, 'Timeout (response)'), this._responseTimeout);
}
_onResult(id, data) {
const info = this._callbacks.get(id);
if (typeof info === 'undefined') {
yomichan.logWarning(new Error(`ID ${id} not found`));
return;
}
if (!info.ack) {
yomichan.logWarning(new Error(`Request ${id} not ack'd`));
return;
}
this._callbacks.delete(id);
clearTimeout(info.timer);
info.timer = null;
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if (typeof data.error !== 'undefined') {
info.reject(jsonToError(data.error));
} else {
info.resolve(data.result);
}
}
_onError(id, reason) {
const info = this._callbacks.get(id);
if (typeof info === 'undefined') { return; }
this._callbacks.delete(id);
info.timer = null;
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info.reject(new Error(reason));
}
}