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lib/jsdom/living/file-api/FileReader-impl.js 3.58 KB
858f2bdf5   Boyan Georgiev   fixes
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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;