yomichan/ext/js/language/dictionary-worker-media-loader.js
toasted-nutbread 3e350bd563
Dictionary worker refactor (#1894)
* Rename dictionary worker files

* Rename classes

* Rename file

* Rename class

* Generalize the _invoke method

* Rename 'import' to 'importDictionary'

* Improve DictionaryImporterMediaLoader usage

* Refactor message handler

* Generalize onProgress event
2021-08-14 11:46:26 -04:00

66 lines
2.2 KiB
JavaScript

/*
* Copyright (C) 2021 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
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/**
* Class used for loading and validating media from a worker thread
* during the dictionary import process.
*/
class DictionaryWorkerMediaLoader {
/**
* Creates a new instance of the media loader.
*/
constructor() {
this._requests = new Map();
}
/**
* Handles a response message posted to the worker thread.
* @param params Details of the response.
*/
handleMessage(params) {
const {id} = params;
const request = this._requests.get(id);
if (typeof request === 'undefined') { return; }
this._requests.delete(id);
const {error} = params;
if (typeof error !== 'undefined') {
request.reject(deserializeError(error));
} else {
request.resolve(params.result);
}
}
/**
* Attempts to load an image using a base64 encoded content and a media type
* and returns its resolution.
* @param mediaType The media type for the image content.
* @param content The binary content for the image, encoded in base64.
* @returns A Promise which resolves with {width, height} on success,
* otherwise an error is thrown.
*/
getImageResolution(mediaType, content) {
return new Promise((resolve, reject) => {
const id = generateId(16);
this._requests.set(id, {resolve, reject});
self.postMessage({
action: 'getImageResolution',
params: {id, mediaType, content}
});
});
}
}