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const Preloader = /** @constructor */ function () { // eslint-disable-line no-unused-vars
function getTrackedResponse(response, load_status) {
let clen = 0;
let compressed = false;
response.headers.forEach(function (value, header) {
const h = header.toLowerCase().trim();
// We can't accurately compute compressed stream length.
if (h === 'content-encoding') {
compressed = true;
} else if (h === 'content-length') {
const length = parseInt(value, 10);
if (!Number.isNaN(length) && length > 0) {
clen = length;
}
}
});
if (!compressed && clen) {
load_status.total = clen;
}
function onloadprogress(reader, controller) {
return reader.read().then(function (result) {
if (load_status.done) {
return Promise.resolve();
}
if (result.value) {
controller.enqueue(result.value);
load_status.loaded += result.value.length;
}
if (!result.done) {
return onloadprogress(reader, controller);
}
load_status.done = true;
return Promise.resolve();
});
}
const reader = response.body.getReader();
return new Response(new ReadableStream({
start: function (controller) {
onloadprogress(reader, controller).then(function () {
controller.close();
});
},
}), { headers: response.headers });
}
function loadFetch(file, tracker, fileSize, raw) {
tracker[file] = {
total: fileSize || 0,
loaded: 0,
done: false,
};
return fetch(file).then(function (response) {
if (!response.ok) {
return Promise.reject(new Error(`Failed loading file '${file}'`));
}
const tr = getTrackedResponse(response, tracker[file]);
if (raw) {
return Promise.resolve(tr);
}
return tr.arrayBuffer();
});
}
function retry(func, attempts = 1) {
function onerror(err) {
if (attempts <= 1) {
return Promise.reject(err);
}
return new Promise(function (resolve, reject) {
setTimeout(function () {
retry(func, attempts - 1).then(resolve).catch(reject);
}, 1000);
});
}
return func().catch(onerror);
}
const DOWNLOAD_ATTEMPTS_MAX = 4;
const loadingFiles = {};
const lastProgress = { loaded: 0, total: 0 };
let progressFunc = null;
const animateProgress = function () {
let loaded = 0;
let total = 0;
let totalIsValid = true;
let progressIsFinal = true;
Object.keys(loadingFiles).forEach(function (file) {
const stat = loadingFiles[file];
if (!stat.done) {
progressIsFinal = false;
}
if (!totalIsValid || stat.total === 0) {
totalIsValid = false;
total = 0;
} else {
total += stat.total;
}
loaded += stat.loaded;
});
if (loaded !== lastProgress.loaded || total !== lastProgress.total) {
lastProgress.loaded = loaded;
lastProgress.total = total;
if (typeof progressFunc === 'function') {
progressFunc(loaded, total);
}
}
if (!progressIsFinal) {
requestAnimationFrame(animateProgress);
}
};
this.animateProgress = animateProgress;
this.setProgressFunc = function (callback) {
progressFunc = callback;
};
this.loadPromise = function (file, fileSize, raw = false) {
return retry(loadFetch.bind(null, file, loadingFiles, fileSize, raw), DOWNLOAD_ATTEMPTS_MAX);
};
this.preloadedFiles = [];
this.preload = function (pathOrBuffer, destPath, fileSize) {
let buffer = null;
if (typeof pathOrBuffer === 'string') {
const me = this;
return this.loadPromise(pathOrBuffer, fileSize).then(function (buf) {
me.preloadedFiles.push({
path: destPath || pathOrBuffer,
buffer: buf,
});
return Promise.resolve();
});
} else if (pathOrBuffer instanceof ArrayBuffer) {
buffer = new Uint8Array(pathOrBuffer);
} else if (ArrayBuffer.isView(pathOrBuffer)) {
buffer = new Uint8Array(pathOrBuffer.buffer);
}
if (buffer) {
this.preloadedFiles.push({
path: destPath,
buffer: pathOrBuffer,
});
return Promise.resolve();
}
return Promise.reject(new Error('Invalid object for preloading'));
};
};
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