libs/Blob.js

/**
 * @license
 * Blob.js
 * A Blob, File, FileReader & URL implementation.
 * 2018-08-09
 *
 * By Eli Grey, http://eligrey.com
 * By Jimmy Wärting, https://github.com/jimmywarting
 * License: MIT
 *   See https://github.com/eligrey/Blob.js/blob/master/LICENSE.md
 */

import { globalObject as global } from "./globalObject.js";

var BlobBuilder =
  global.BlobBuilder ||
  global.WebKitBlobBuilder ||
  global.MSBlobBuilder ||
  global.MozBlobBuilder;

global.URL =
  global.URL ||
  global.webkitURL ||
  function(href, a) {
    a = document.createElement("a");
    a.href = href;
    return a;
  };

var origBlob = global.Blob;
var createObjectURL = URL.createObjectURL;
var revokeObjectURL = URL.revokeObjectURL;
var strTag = global.Symbol && global.Symbol.toStringTag;
var blobSupported = false;
var blobSupportsArrayBufferView = false;
var arrayBufferSupported = !!global.ArrayBuffer;
var blobBuilderSupported =
  BlobBuilder && BlobBuilder.prototype.append && BlobBuilder.prototype.getBlob;

try {
  // Check if Blob constructor is supported
  blobSupported = new Blob(["ä"]).size === 2;

  // Check if Blob constructor supports ArrayBufferViews
  // Fails in Safari 6, so we need to map to ArrayBuffers there.
  blobSupportsArrayBufferView = new Blob([new Uint8Array([1, 2])]).size === 2;
} catch (e) {}

/**
 * Helper function that maps ArrayBufferViews to ArrayBuffers
 * Used by BlobBuilder constructor and old browsers that didn't
 * support it in the Blob constructor.
 */
function mapArrayBufferViews(ary) {
  return ary.map(function(chunk) {
    if (chunk.buffer instanceof ArrayBuffer) {
      var buf = chunk.buffer;

      // if this is a subarray, make a copy so we only
      // include the subarray region from the underlying buffer
      if (chunk.byteLength !== buf.byteLength) {
        var copy = new Uint8Array(chunk.byteLength);
        copy.set(new Uint8Array(buf, chunk.byteOffset, chunk.byteLength));
        buf = copy.buffer;
      }

      return buf;
    }

    return chunk;
  });
}

function BlobBuilderConstructor(ary, options) {
  options = options || {};

  var bb = new BlobBuilder();
  mapArrayBufferViews(ary).forEach(function(part) {
    bb.append(part);
  });

  return options.type ? bb.getBlob(options.type) : bb.getBlob();
}

function BlobConstructor(ary, options) {
  return new origBlob(mapArrayBufferViews(ary), options || {});
}

if (global.Blob) {
  BlobBuilderConstructor.prototype = Blob.prototype;
  BlobConstructor.prototype = Blob.prototype;
}

function FakeBlobBuilder() {
  function toUTF8Array(str) {
    var utf8 = [];
    for (var i = 0; i < str.length; i++) {
      var charcode = str.charCodeAt(i);
      if (charcode < 0x80) utf8.push(charcode);
      else if (charcode < 0x800) {
        utf8.push(0xc0 | (charcode >> 6), 0x80 | (charcode & 0x3f));
      } else if (charcode < 0xd800 || charcode >= 0xe000) {
        utf8.push(
          0xe0 | (charcode >> 12),
          0x80 | ((charcode >> 6) & 0x3f),
          0x80 | (charcode & 0x3f)
        );
      }
      // surrogate pair
      else {
        i++;
        // UTF-16 encodes 0x10000-0x10FFFF by
        // subtracting 0x10000 and splitting the
        // 20 bits of 0x0-0xFFFFF into two halves
        charcode =
          0x10000 + (((charcode & 0x3ff) << 10) | (str.charCodeAt(i) & 0x3ff));
        utf8.push(
          0xf0 | (charcode >> 18),
          0x80 | ((charcode >> 12) & 0x3f),
          0x80 | ((charcode >> 6) & 0x3f),
          0x80 | (charcode & 0x3f)
        );
      }
    }
    return utf8;
  }
  function fromUtf8Array(array) {
    var out, i, len, c;
    var char2, char3;

    out = "";
    len = array.length;
    i = 0;
    while (i < len) {
      c = array[i++];
      switch (c >> 4) {
        case 0:
        case 1:
        case 2:
        case 3:
        case 4:
        case 5:
        case 6:
        case 7:
          // 0xxxxxxx
          out += String.fromCharCode(c);
          break;
        case 12:
        case 13:
          // 110x xxxx   10xx xxxx
          char2 = array[i++];
          out += String.fromCharCode(((c & 0x1f) << 6) | (char2 & 0x3f));
          break;
        case 14:
          // 1110 xxxx  10xx xxxx  10xx xxxx
          char2 = array[i++];
          char3 = array[i++];
          out += String.fromCharCode(
            ((c & 0x0f) << 12) | ((char2 & 0x3f) << 6) | ((char3 & 0x3f) << 0)
          );
          break;
      }
    }
    return out;
  }
  function isDataView(obj) {
    return obj && DataView.prototype.isPrototypeOf(obj);
  }
  function bufferClone(buf) {
    var view = new Array(buf.byteLength);
    var array = new Uint8Array(buf);
    var i = view.length;
    while (i--) {
      view[i] = array[i];
    }
    return view;
  }
  function encodeByteArray(input) {
    var byteToCharMap =
      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

    var output = [];

    for (var i = 0; i < input.length; i += 3) {
      var byte1 = input[i];
      var haveByte2 = i + 1 < input.length;
      var byte2 = haveByte2 ? input[i + 1] : 0;
      var haveByte3 = i + 2 < input.length;
      var byte3 = haveByte3 ? input[i + 2] : 0;

      var outByte1 = byte1 >> 2;
      var outByte2 = ((byte1 & 0x03) << 4) | (byte2 >> 4);
      var outByte3 = ((byte2 & 0x0f) << 2) | (byte3 >> 6);
      var outByte4 = byte3 & 0x3f;

      if (!haveByte3) {
        outByte4 = 64;

        if (!haveByte2) {
          outByte3 = 64;
        }
      }

      output.push(
        byteToCharMap[outByte1],
        byteToCharMap[outByte2],
        byteToCharMap[outByte3],
        byteToCharMap[outByte4]
      );
    }

    return output.join("");
  }

  var create =
    Object.create ||
    function(a) {
      function c() {}
      c.prototype = a;
      return new c();
    };

  if (arrayBufferSupported) {
    var viewClasses = [
      "[object Int8Array]",
      "[object Uint8Array]",
      "[object Uint8ClampedArray]",
      "[object Int16Array]",
      "[object Uint16Array]",
      "[object Int32Array]",
      "[object Uint32Array]",
      "[object Float32Array]",
      "[object Float64Array]"
    ];

    var isArrayBufferView =
      ArrayBuffer.isView ||
      function(obj) {
        return (
          obj && viewClasses.indexOf(Object.prototype.toString.call(obj)) > -1
        );
      };
  }

  /********************************************************/
  /*                   Blob constructor                   */
  /********************************************************/
  function Blob(chunks, opts) {
    chunks = chunks || [];
    for (var i = 0, len = chunks.length; i < len; i++) {
      var chunk = chunks[i];
      if (chunk instanceof Blob) {
        chunks[i] = chunk._buffer;
      } else if (typeof chunk === "string") {
        chunks[i] = toUTF8Array(chunk);
      } else if (
        arrayBufferSupported &&
        (ArrayBuffer.prototype.isPrototypeOf(chunk) || isArrayBufferView(chunk))
      ) {
        chunks[i] = bufferClone(chunk);
      } else if (arrayBufferSupported && isDataView(chunk)) {
        chunks[i] = bufferClone(chunk.buffer);
      } else {
        chunks[i] = toUTF8Array(String(chunk));
      }
    }

    this._buffer = [].concat.apply([], chunks);
    this.size = this._buffer.length;
    this.type = opts ? opts.type || "" : "";
  }

  Blob.prototype.slice = function(start, end, type) {
    var slice = this._buffer.slice(start || 0, end || this._buffer.length);
    return new Blob([slice], { type: type });
  };

  Blob.prototype.toString = function() {
    return "[object Blob]";
  };

  /********************************************************/
  /*                   File constructor                   */
  /********************************************************/
  function File(chunks, name, opts) {
    opts = opts || {};
    var a = Blob.call(this, chunks, opts) || this;
    a.name = name;
    a.lastModifiedDate = opts.lastModified
      ? new Date(opts.lastModified)
      : new Date();
    a.lastModified = +a.lastModifiedDate;

    return a;
  }

  File.prototype = create(Blob.prototype);
  File.prototype.constructor = File;

  if (Object.setPrototypeOf) Object.setPrototypeOf(File, Blob);
  else {
    try {
      File.__proto__ = Blob;
    } catch (e) {}
  }

  File.prototype.toString = function() {
    return "[object File]";
  };

  /********************************************************/
  /*                FileReader constructor                */
  /********************************************************/
  function FileReader() {
    if (!(this instanceof FileReader))
      throw new TypeError(
        "Failed to construct 'FileReader': Please use the 'new' operator, this DOM object constructor cannot be called as a function."
      );

    var delegate = document.createDocumentFragment();
    this.addEventListener = delegate.addEventListener;
    this.dispatchEvent = function(evt) {
      var local = this["on" + evt.type];
      if (typeof local === "function") local(evt);
      delegate.dispatchEvent(evt);
    };
    this.removeEventListener = delegate.removeEventListener;
  }

  function _read(fr, blob, kind) {
    if (!(blob instanceof Blob))
      throw new TypeError(
        "Failed to execute '" +
          kind +
          "' on 'FileReader': parameter 1 is not of type 'Blob'."
      );

    fr.result = "";

    setTimeout(function() {
      this.readyState = FileReader.LOADING;
      fr.dispatchEvent(new Event("load"));
      fr.dispatchEvent(new Event("loadend"));
    });
  }

  FileReader.EMPTY = 0;
  FileReader.LOADING = 1;
  FileReader.DONE = 2;
  FileReader.prototype.error = null;
  FileReader.prototype.onabort = null;
  FileReader.prototype.onerror = null;
  FileReader.prototype.onload = null;
  FileReader.prototype.onloadend = null;
  FileReader.prototype.onloadstart = null;
  FileReader.prototype.onprogress = null;

  FileReader.prototype.readAsDataURL = function(blob) {
    _read(this, blob, "readAsDataURL");
    this.result =
      "data:" + blob.type + ";base64," + encodeByteArray(blob._buffer);
  };

  FileReader.prototype.readAsText = function(blob) {
    _read(this, blob, "readAsText");
    this.result = fromUtf8Array(blob._buffer);
  };

  FileReader.prototype.readAsArrayBuffer = function(blob) {
    _read(this, blob, "readAsText");
    this.result = blob._buffer.slice();
  };

  FileReader.prototype.abort = function() {};

  /********************************************************/
  /*                         URL                          */
  /********************************************************/
  URL.createObjectURL = function(blob) {
    return blob instanceof Blob
      ? "data:" + blob.type + ";base64," + encodeByteArray(blob._buffer)
      : createObjectURL.call(URL, blob);
  };

  URL.revokeObjectURL = function(url) {
    revokeObjectURL && revokeObjectURL.call(URL, url);
  };

  /********************************************************/
  /*                         XHR                          */
  /********************************************************/
  var _send = global.XMLHttpRequest && global.XMLHttpRequest.prototype.send;
  if (_send) {
    XMLHttpRequest.prototype.send = function(data) {
      if (data instanceof Blob) {
        this.setRequestHeader("Content-Type", data.type);
        _send.call(this, fromUtf8Array(data._buffer));
      } else {
        _send.call(this, data);
      }
    };
  }

  global.FileReader = FileReader;
  global.File = File;
  global.Blob = Blob;
}

if (strTag) {
  try {
    File.prototype[strTag] = "File";
    Blob.prototype[strTag] = "Blob";
    FileReader.prototype[strTag] = "FileReader";
  } catch (e) {}
}

function fixFileAndXHR() {
  var isIE =
    !!global.ActiveXObject ||
    ("-ms-scroll-limit" in document.documentElement.style &&
      "-ms-ime-align" in document.documentElement.style);

  // Monkey patched
  // IE don't set Content-Type header on XHR whose body is a typed Blob
  // https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/6047383
  var _send = global.XMLHttpRequest && global.XMLHttpRequest.prototype.send;
  if (isIE && _send) {
    XMLHttpRequest.prototype.send = function(data) {
      if (data instanceof Blob) {
        this.setRequestHeader("Content-Type", data.type);
        _send.call(this, data);
      } else {
        _send.call(this, data);
      }
    };
  }

  try {
    new File([], "");
  } catch (e) {
    try {
      var klass = new Function(
        "class File extends Blob {" +
          "constructor(chunks, name, opts) {" +
          "opts = opts || {};" +
          "super(chunks, opts || {});" +
          "this.name = name;" +
          "this.lastModifiedDate = opts.lastModified ? new Date(opts.lastModified) : new Date;" +
          "this.lastModified = +this.lastModifiedDate;" +
          "}};" +
          'return new File([], ""), File'
      )();
      global.File = klass;
    } catch (e) {
      var klass = function(b, d, c) {
        var blob = new Blob(b, c);
        var t =
          c && void 0 !== c.lastModified
            ? new Date(c.lastModified)
            : new Date();

        blob.name = d;
        blob.lastModifiedDate = t;
        blob.lastModified = +t;
        blob.toString = function() {
          return "[object File]";
        };

        if (strTag) blob[strTag] = "File";

        return blob;
      };
      global.File = klass;
    }
  }
}

if (blobSupported) {
  fixFileAndXHR();
  global.Blob = blobSupportsArrayBufferView ? global.Blob : BlobConstructor;
} else if (blobBuilderSupported) {
  fixFileAndXHR();
  global.Blob = BlobBuilderConstructor;
} else {
  FakeBlobBuilder();
}