mirror of
https://github.com/denoland/deno.git
synced 2024-10-31 09:14:20 -04:00
265 lines
8.6 KiB
JavaScript
265 lines
8.6 KiB
JavaScript
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// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
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((window) => {
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const base64 = window.__bootstrap.base64;
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const setTimeout = window.__bootstrap.timers.setTimeout;
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// ProgressEvent could also be used in other DOM progress event emits.
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// Current use is for FileReader.
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class ProgressEvent extends Event {
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constructor(type, eventInitDict = {}) {
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super(type, eventInitDict);
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this.lengthComputable = eventInitDict?.lengthComputable ?? false;
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this.loaded = eventInitDict?.loaded ?? 0;
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this.total = eventInitDict?.total ?? 0;
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}
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}
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window.__bootstrap.progressEvent = {
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ProgressEvent,
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};
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async function readOperation(fr, blob, readtype) {
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// Implementation from https://w3c.github.io/FileAPI/ notes
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// And body of deno blob.ts readBytes
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fr.aborting = false;
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// 1. If fr’s state is "loading", throw an InvalidStateError DOMException.
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if (fr.readyState === FileReader.LOADING) {
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throw new DOMException(
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"Invalid FileReader state.",
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"InvalidStateError",
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);
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}
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// 2. Set fr’s state to "loading".
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fr.readyState = FileReader.LOADING;
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// 3. Set fr’s result to null.
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fr.result = null;
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// 4. Set fr’s error to null.
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fr.error = null;
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// 5. Let stream be the result of calling get stream on blob.
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const stream /*: ReadableStream<ArrayBufferView>*/ = blob.stream();
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// 6. Let reader be the result of getting a reader from stream.
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const reader = stream.getReader();
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// 7. Let bytes be an empty byte sequence.
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//let bytes = new Uint8Array();
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const chunks /*: Uint8Array[]*/ = [];
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// 8. Let chunkPromise be the result of reading a chunk from stream with reader.
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let chunkPromise = reader.read();
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// 9. Let isFirstChunk be true.
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let isFirstChunk = true;
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// 10 in parallel while true
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while (!fr.aborting) {
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// 1. Wait for chunkPromise to be fulfilled or rejected.
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try {
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const chunk = await chunkPromise;
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// 2. If chunkPromise is fulfilled, and isFirstChunk is true, queue a task to fire a progress event called loadstart at fr.
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if (isFirstChunk) {
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setTimeout(() => {
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// fire a progress event for loadstart
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const ev = new ProgressEvent("loadstart", {});
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fr.dispatchEvent(ev);
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if (fr.onloadstart !== null) {
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fr.onloadstart(ev);
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}
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}, 0);
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}
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// 3. Set isFirstChunk to false.
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isFirstChunk = false;
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// 4. If chunkPromise is fulfilled with an object whose done property is false
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// and whose value property is a Uint8Array object, run these steps:
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if (!chunk.done && chunk.value instanceof Uint8Array) {
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chunks.push(chunk.value);
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// TODO: (only) If roughly 50ms have passed since last progress
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{
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const size = chunks.reduce((p, i) => p + i.byteLength, 0);
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const ev = new ProgressEvent("progress", {
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loaded: size,
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});
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fr.dispatchEvent(ev);
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if (fr.onprogress !== null) {
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fr.onprogress(ev);
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}
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}
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chunkPromise = reader.read();
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} // 5 Otherwise, if chunkPromise is fulfilled with an object whose done property is true, queue a task to run the following steps and abort this algorithm:
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else if (chunk.done === true) {
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setTimeout(() => {
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if (fr.aborting) {
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return;
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}
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// 1. Set fr’s state to "done".
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fr.readyState = FileReader.DONE;
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// 2. Let result be the result of package data given bytes, type, blob’s type, and encodingName.
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const size = chunks.reduce((p, i) => p + i.byteLength, 0);
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const bytes = new Uint8Array(size);
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let offs = 0;
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for (const chunk of chunks) {
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bytes.set(chunk, offs);
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offs += chunk.byteLength;
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}
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switch (readtype.kind) {
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case "ArrayBuffer": {
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fr.result = bytes.buffer;
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break;
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}
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case "Text": {
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const decoder = new TextDecoder(readtype.encoding);
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fr.result = decoder.decode(bytes.buffer);
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break;
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}
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case "DataUrl": {
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fr.result = "data:application/octet-stream;base64," +
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base64.fromByteArray(bytes);
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break;
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}
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}
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// 4.2 Fire a progress event called load at the fr.
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{
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const ev = new ProgressEvent("load", {
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lengthComputable: true,
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loaded: size,
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total: size,
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});
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fr.dispatchEvent(ev);
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if (fr.onload !== null) {
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fr.onload(ev);
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}
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}
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// 5. If fr’s state is not "loading", fire a progress event called loadend at the fr.
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//Note: Event handler for the load or error events could have started another load, if that happens the loadend event for this load is not fired.
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if (fr.readyState !== FileReader.LOADING) {
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const ev = new ProgressEvent("loadend", {
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lengthComputable: true,
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loaded: size,
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total: size,
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});
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fr.dispatchEvent(ev);
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if (fr.onloadend !== null) {
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fr.onloadend(ev);
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}
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}
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}, 0);
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break;
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}
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} catch (err) {
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if (fr.aborting) {
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break;
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}
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// chunkPromise rejected
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fr.readyState = FileReader.DONE;
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fr.error = err;
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{
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const ev = new ProgressEvent("error", {});
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fr.dispatchEvent(ev);
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if (fr.onerror !== null) {
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fr.onerror(ev);
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}
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}
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//If fr’s state is not "loading", fire a progress event called loadend at fr.
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//Note: Event handler for the error event could have started another load, if that happens the loadend event for this load is not fired.
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if (fr.readyState !== FileReader.LOADING) {
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const ev = new ProgressEvent("loadend", {});
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fr.dispatchEvent(ev);
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if (fr.onloadend !== null) {
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fr.onloadend(ev);
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}
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}
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break;
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}
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}
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}
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class FileReader extends EventTarget {
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error = null;
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onabort = null;
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onerror = null;
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onload = null;
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onloadend = null;
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onloadstart = null;
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onprogress = null;
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readyState = FileReader.EMPTY;
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result = null;
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aborting = false;
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constructor() {
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super();
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}
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abort() {
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// If context object's state is "empty" or if context object's state is "done" set context object's result to null and terminate this algorithm.
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if (
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this.readyState === FileReader.EMPTY ||
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this.readyState === FileReader.DONE
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) {
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this.result = null;
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return;
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}
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// If context object's state is "loading" set context object's state to "done" and set context object's result to null.
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if (this.readyState === FileReader.LOADING) {
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this.readyState = FileReader.DONE;
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this.result = null;
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}
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// If there are any tasks from the context object on the file reading task source in an affiliated task queue, then remove those tasks from that task queue.
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// Terminate the algorithm for the read method being processed.
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this.aborting = true;
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// Fire a progress event called abort at the context object.
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const ev = new ProgressEvent("abort", {});
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this.dispatchEvent(ev);
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if (this.onabort !== null) {
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this.onabort(ev);
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}
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// If context object's state is not "loading", fire a progress event called loadend at the context object.
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if (this.readyState !== FileReader.LOADING) {
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const ev = new ProgressEvent("loadend", {});
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this.dispatchEvent(ev);
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if (this.onloadend !== null) {
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this.onloadend(ev);
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}
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}
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}
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readAsArrayBuffer(blob) {
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readOperation(this, blob, { kind: "ArrayBuffer" });
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}
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readAsBinaryString(blob) {
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// alias for readAsArrayBuffer
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readOperation(this, blob, { kind: "ArrayBuffer" });
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}
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readAsDataURL(blob) {
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readOperation(this, blob, { kind: "DataUrl" });
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}
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readAsText(blob, encoding) {
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readOperation(this, blob, { kind: "Text", encoding });
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}
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}
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FileReader.EMPTY = 0;
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FileReader.LOADING = 1;
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FileReader.DONE = 2;
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window.__bootstrap.fileReader = {
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FileReader,
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};
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})(this);
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