134 lines
3.4 KiB
JavaScript
134 lines
3.4 KiB
JavaScript
const Preloader = /** @constructor */ function () { // eslint-disable-line no-unused-vars
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function getTrackedResponse(response, load_status) {
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function onloadprogress(reader, controller) {
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return reader.read().then(function (result) {
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if (load_status.done) {
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return Promise.resolve();
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}
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if (result.value) {
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controller.enqueue(result.value);
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load_status.loaded += result.value.length;
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}
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if (!result.done) {
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return onloadprogress(reader, controller);
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}
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load_status.done = true;
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return Promise.resolve();
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});
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}
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const reader = response.body.getReader();
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return new Response(new ReadableStream({
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start: function (controller) {
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onloadprogress(reader, controller).then(function () {
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controller.close();
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});
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},
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}), { headers: response.headers });
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}
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function loadFetch(file, tracker, fileSize, raw) {
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tracker[file] = {
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total: fileSize || 0,
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loaded: 0,
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done: false,
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};
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return fetch(file).then(function (response) {
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if (!response.ok) {
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return Promise.reject(new Error(`Failed loading file '${file}'`));
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}
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const tr = getTrackedResponse(response, tracker[file]);
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if (raw) {
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return Promise.resolve(tr);
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}
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return tr.arrayBuffer();
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});
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}
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function retry(func, attempts = 1) {
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function onerror(err) {
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if (attempts <= 1) {
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return Promise.reject(err);
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}
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return new Promise(function (resolve, reject) {
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setTimeout(function () {
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retry(func, attempts - 1).then(resolve).catch(reject);
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}, 1000);
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});
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}
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return func().catch(onerror);
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}
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const DOWNLOAD_ATTEMPTS_MAX = 4;
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const loadingFiles = {};
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const lastProgress = { loaded: 0, total: 0 };
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let progressFunc = null;
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const animateProgress = function () {
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let loaded = 0;
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let total = 0;
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let totalIsValid = true;
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let progressIsFinal = true;
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Object.keys(loadingFiles).forEach(function (file) {
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const stat = loadingFiles[file];
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if (!stat.done) {
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progressIsFinal = false;
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}
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if (!totalIsValid || stat.total === 0) {
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totalIsValid = false;
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total = 0;
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} else {
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total += stat.total;
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}
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loaded += stat.loaded;
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});
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if (loaded !== lastProgress.loaded || total !== lastProgress.total) {
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lastProgress.loaded = loaded;
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lastProgress.total = total;
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if (typeof progressFunc === 'function') {
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progressFunc(loaded, total);
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}
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}
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if (!progressIsFinal) {
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requestAnimationFrame(animateProgress);
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}
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};
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this.animateProgress = animateProgress;
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this.setProgressFunc = function (callback) {
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progressFunc = callback;
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};
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this.loadPromise = function (file, fileSize, raw = false) {
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return retry(loadFetch.bind(null, file, loadingFiles, fileSize, raw), DOWNLOAD_ATTEMPTS_MAX);
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};
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this.preloadedFiles = [];
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this.preload = function (pathOrBuffer, destPath, fileSize) {
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let buffer = null;
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if (typeof pathOrBuffer === 'string') {
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const me = this;
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return this.loadPromise(pathOrBuffer, fileSize).then(function (buf) {
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me.preloadedFiles.push({
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path: destPath || pathOrBuffer,
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buffer: buf,
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});
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return Promise.resolve();
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});
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} else if (pathOrBuffer instanceof ArrayBuffer) {
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buffer = new Uint8Array(pathOrBuffer);
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} else if (ArrayBuffer.isView(pathOrBuffer)) {
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buffer = new Uint8Array(pathOrBuffer.buffer);
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}
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if (buffer) {
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this.preloadedFiles.push({
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path: destPath,
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buffer: pathOrBuffer,
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});
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return Promise.resolve();
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}
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return Promise.reject(new Error('Invalid object for preloading'));
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};
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};
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