155 lines
3.1 KiB
JavaScript
155 lines
3.1 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @providesModule FileReader
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* @flow
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* @format
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*/
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'use strict';
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const EventTarget = require('event-target-shim');
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const Blob = require('Blob');
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const {FileReaderModule} = require('NativeModules');
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type ReadyState =
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| 0 // EMPTY
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| 1 // LOADING
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| 2; // DONE
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type ReaderResult = string | ArrayBuffer;
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const READER_EVENTS = [
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'abort',
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'error',
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'load',
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'loadstart',
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'loadend',
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'progress',
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];
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const EMPTY = 0;
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const LOADING = 1;
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const DONE = 2;
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class FileReader extends EventTarget(...READER_EVENTS) {
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static EMPTY = EMPTY;
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static LOADING = LOADING;
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static DONE = DONE;
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EMPTY = EMPTY;
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LOADING = LOADING;
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DONE = DONE;
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_readyState: ReadyState;
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_error: ?Error;
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_result: ?ReaderResult;
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_aborted: boolean = false;
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_subscriptions: Array<*> = [];
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constructor() {
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super();
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this._reset();
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}
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_reset(): void {
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this._readyState = EMPTY;
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this._error = null;
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this._result = null;
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}
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_clearSubscriptions(): void {
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this._subscriptions.forEach(sub => sub.remove());
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this._subscriptions = [];
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}
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_setReadyState(newState: ReadyState) {
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this._readyState = newState;
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this.dispatchEvent({type: 'readystatechange'});
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if (newState === DONE) {
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if (this._aborted) {
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this.dispatchEvent({type: 'abort'});
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} else if (this._error) {
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this.dispatchEvent({type: 'error'});
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} else {
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this.dispatchEvent({type: 'load'});
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}
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this.dispatchEvent({type: 'loadend'});
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}
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}
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readAsArrayBuffer() {
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throw new Error('FileReader.readAsArrayBuffer is not implemented');
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}
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readAsDataURL(blob: Blob) {
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this._aborted = false;
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FileReaderModule.readAsDataURL(blob.data).then(
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(text: string) => {
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if (this._aborted) {
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return;
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}
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this._result = text;
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this._setReadyState(DONE);
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},
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error => {
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if (this._aborted) {
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return;
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}
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this._error = error;
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this._setReadyState(DONE);
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},
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);
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}
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readAsText(blob: Blob, encoding: string = 'UTF-8') {
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this._aborted = false;
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FileReaderModule.readAsText(blob.data, encoding).then(
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(text: string) => {
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if (this._aborted) {
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return;
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}
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this._result = text;
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this._setReadyState(DONE);
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},
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error => {
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if (this._aborted) {
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return;
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}
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this._error = error;
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this._setReadyState(DONE);
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},
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);
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}
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abort() {
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this._aborted = true;
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// only call onreadystatechange if there is something to abort, as per spec
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if (this._readyState !== EMPTY && this._readyState !== DONE) {
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this._reset();
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this._setReadyState(DONE);
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}
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// Reset again after, in case modified in handler
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this._reset();
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}
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get readyState(): ReadyState {
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return this._readyState;
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}
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get error(): ?Error {
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return this._error;
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}
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get result(): ?ReaderResult {
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return this._result;
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}
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}
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module.exports = FileReader;
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