FileReader-impl.js
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"use strict";
const whatwgEncoding = require("whatwg-encoding");
const MIMEType = require("whatwg-mimetype");
const DOMException = require("domexception/webidl2js-wrapper");
const EventTargetImpl = require("../events/EventTarget-impl").implementation;
const ProgressEvent = require("../generated/ProgressEvent");
const { setupForSimpleEventAccessors } = require("../helpers/create-event-accessor");
const { fireAnEvent } = require("../helpers/events");
const { copyToArrayBufferInNewRealm } = require("../helpers/binary-data");
const READY_STATES = Object.freeze({
EMPTY: 0,
LOADING: 1,
DONE: 2
});
const events = ["loadstart", "progress", "load", "abort", "error", "loadend"];
class FileReaderImpl extends EventTargetImpl {
constructor(globalObject, args, privateData) {
super(globalObject, args, privateData);
this.error = null;
this.readyState = READY_STATES.EMPTY;
this.result = null;
this._globalObject = globalObject;
this._ownerDocument = globalObject.document;
this._terminated = false;
}
readAsArrayBuffer(file) {
this._readFile(file, "buffer");
}
readAsBinaryString(file) {
this._readFile(file, "binaryString");
}
readAsDataURL(file) {
this._readFile(file, "dataURL");
}
readAsText(file, encoding) {
this._readFile(file, "text", whatwgEncoding.labelToName(encoding) || "UTF-8");
}
abort() {
if (this.readyState === READY_STATES.EMPTY || this.readyState === READY_STATES.DONE) {
this.result = null;
return;
}
if (this.readyState === READY_STATES.LOADING) {
this.readyState = READY_STATES.DONE;
this.result = null;
}
this._terminated = true;
this._fireProgressEvent("abort");
this._fireProgressEvent("loadend");
}
_fireProgressEvent(name, props) {
fireAnEvent(name, this, ProgressEvent, props);
}
_readFile(file, format, encoding) {
if (this.readyState === READY_STATES.LOADING) {
throw DOMException.create(this._globalObject, [
"The object is in an invalid state.",
"InvalidStateError"
]);
}
this.readyState = READY_STATES.LOADING;
setImmediate(() => {
if (this._terminated) {
this._terminated = false;
return;
}
this._fireProgressEvent("loadstart");
let data = file._buffer;
if (!data) {
data = Buffer.alloc(0);
}
this._fireProgressEvent("progress", {
lengthComputable: !isNaN(file.size),
total: file.size,
loaded: data.length
});
setImmediate(() => {
if (this._terminated) {
this._terminated = false;
return;
}
switch (format) {
default:
case "buffer": {
this.result = copyToArrayBufferInNewRealm(data, this._globalObject);
break;
}
case "binaryString": {
this.result = data.toString("binary");
break;
}
case "dataURL": {
// Spec seems very unclear here; see https://github.com/w3c/FileAPI/issues/104.
const contentType = MIMEType.parse(file.type) || "application/octet-stream";
this.result = `data:${contentType};base64,${data.toString("base64")}`;
break;
}
case "text": {
this.result = whatwgEncoding.decode(data, encoding);
break;
}
}
this.readyState = READY_STATES.DONE;
this._fireProgressEvent("load");
this._fireProgressEvent("loadend");
});
});
}
}
setupForSimpleEventAccessors(FileReaderImpl.prototype, events);
exports.implementation = FileReaderImpl;