/
suspension-manager.js
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/
suspension-manager.js
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/*
This file is part of Talkie -- text-to-speech browser extension button.
<https://joelpurra.com/projects/talkie/>
Copyright (c) 2016, 2017, 2018, 2019 Joel Purra <https://joelpurra.com/>
Talkie 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.
Talkie 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
along with Talkie. If not, see <https://www.gnu.org/licenses/>.
*/
import {
promiseTry,
promiseSleep,
} from "../shared/promise";
import {
logDebug,
logInfo,
} from "../shared/log";
export default class SuspensionManager {
constructor(suspensionConnectorManager) {
// NOTE: the iframe takes care of the SuspensionListenerManager.
this.suspensionConnectorManager = suspensionConnectorManager;
this.stayAliveElementId = "stay-alive-iframe";
this.stayAliveHtmlPath = "/src/stay-alive/stay-alive.html";
}
_getExistingIframe() {
return promiseTry(
() => {
const existingIframe = document.getElementById(this.stayAliveElementId);
return existingIframe;
}
);
}
_isInitialized() {
return this._getExistingIframe()
.then((existingIframe) => existingIframe !== null);
}
_ensureIsInitialized() {
return this._isInitialized()
.then((isInitialized) => {
if (isInitialized === true) {
return undefined;
}
throw new Error("this.stayAliveElementId did not exist.");
});
}
_ensureIsNotInitialized() {
return this._isInitialized()
.then((isInitialized) => {
if (isInitialized === false) {
return undefined;
}
throw new Error("this.stayAliveElementId exists.");
});
}
_injectBackgroundFrame() {
return this._ensureIsNotInitialized()
.then(() => {
const iframe = document.createElement("iframe");
iframe.id = this.stayAliveElementId;
/* eslint-disable no-sync */
iframe.src = this.stayAliveHtmlPath;
/* eslint-enable no-sync */
document.body.appendChild(iframe);
return undefined;
});
}
_removeBackgroundFrame() {
return this._ensureIsInitialized()
.then(() => this._getExistingIframe())
.then((existingIframe) => {
// NOTE: trigger onunload.
// https://stackoverflow.com/questions/8677113/how-to-trigger-onunload-event-when-removing-iframe
existingIframe.src = "about:blank";
existingIframe.src = "the-id-does-not-matter-now";
// NOTE: ensure the src change has time to take effect.
return promiseSleep(() => {
existingIframe.parentNode.removeChild(existingIframe);
}, 10);
});
}
initialize() {
return promiseTry(
() => {
logDebug("Start", "SuspensionManager.initialize");
return this._injectBackgroundFrame()
.then(() => {
logDebug("Done", "SuspensionManager.initialize");
return undefined;
});
}
);
}
unintialize() {
return promiseTry(
() => {
logDebug("Start", "SuspensionManager.unintialize");
return this._removeBackgroundFrame()
.then(() => {
logDebug("Done", "SuspensionManager.unintialize");
return undefined;
});
}
);
}
preventExtensionSuspend() {
return promiseTry(
() => {
logInfo("SuspensionManager.preventExtensionSuspend");
return this._ensureIsInitialized()
.then(() => this.suspensionConnectorManager._connectToStayAlive());
}
);
}
allowExtensionSuspend() {
return promiseTry(
() => {
logInfo("SuspensionManager.allowExtensionSuspend");
return this._ensureIsInitialized()
.then(() => this.suspensionConnectorManager._disconnectToDie());
}
);
}
}