pdf.js/src/shared/util.js

/* Copyright 2012 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/* globals Cmd, ColorSpace, Dict, MozBlobBuilder, Name, PDFJS, Ref, URL,
           Promise */

'use strict';

var globalScope = (typeof window === 'undefined') ? this : window;

var isWorker = (typeof window === 'undefined');

var FONT_IDENTITY_MATRIX = [0.001, 0, 0, 0.001, 0, 0];

var TextRenderingMode = {
  FILL: 0,
  STROKE: 1,
  FILL_STROKE: 2,
  INVISIBLE: 3,
  FILL_ADD_TO_PATH: 4,
  STROKE_ADD_TO_PATH: 5,
  FILL_STROKE_ADD_TO_PATH: 6,
  ADD_TO_PATH: 7,
  FILL_STROKE_MASK: 3,
  ADD_TO_PATH_FLAG: 4
};

var ImageKind = {
  GRAYSCALE_1BPP: 1,
  RGB_24BPP: 2,
  RGBA_32BPP: 3
};

var AnnotationType = {
  TEXT: 1,
  LINK: 2,
  FREETEXT: 3,
  LINE: 4,
  SQUARE: 5,
  CIRCLE: 6,
  POLYGON: 7,
  POLYLINE: 8,
  HIGHLIGHT: 9,
  UNDERLINE: 10,
  SQUIGGLY: 11,
  STRIKEOUT: 12,
  STAMP: 13,
  CARET: 14,
  INK: 15,
  POPUP: 16,
  FILEATTACHMENT: 17,
  SOUND: 18,
  MOVIE: 19,
  WIDGET: 20,
  SCREEN: 21,
  PRINTERMARK: 22,
  TRAPNET: 23,
  WATERMARK: 24,
  THREED: 25,
  REDACT: 26
};

var AnnotationFlag = {
  INVISIBLE: 0x01,
  HIDDEN: 0x02,
  PRINT: 0x04,
  NOZOOM: 0x08,
  NOROTATE: 0x10,
  NOVIEW: 0x20,
  READONLY: 0x40,
  LOCKED: 0x80,
  TOGGLENOVIEW: 0x100,
  LOCKEDCONTENTS: 0x200
};

var AnnotationBorderStyleType = {
  SOLID: 1,
  DASHED: 2,
  BEVELED: 3,
  INSET: 4,
  UNDERLINE: 5
};

var StreamType = {
  UNKNOWN: 0,
  FLATE: 1,
  LZW: 2,
  DCT: 3,
  JPX: 4,
  JBIG: 5,
  A85: 6,
  AHX: 7,
  CCF: 8,
  RL: 9
};

var FontType = {
  UNKNOWN: 0,
  TYPE1: 1,
  TYPE1C: 2,
  CIDFONTTYPE0: 3,
  CIDFONTTYPE0C: 4,
  TRUETYPE: 5,
  CIDFONTTYPE2: 6,
  TYPE3: 7,
  OPENTYPE: 8,
  TYPE0: 9,
  MMTYPE1: 10
};

// The global PDFJS object exposes the API
// In production, it will be declared outside a global wrapper
// In development, it will be declared here
if (!globalScope.PDFJS) {
  globalScope.PDFJS = {};
}

globalScope.PDFJS.pdfBug = false;

PDFJS.VERBOSITY_LEVELS = {
  errors: 0,
  warnings: 1,
  infos: 5
};

// All the possible operations for an operator list.
var OPS = PDFJS.OPS = {
  // Intentionally start from 1 so it is easy to spot bad operators that will be
  // 0's.
  dependency: 1,
  setLineWidth: 2,
  setLineCap: 3,
  setLineJoin: 4,
  setMiterLimit: 5,
  setDash: 6,
  setRenderingIntent: 7,
  setFlatness: 8,
  setGState: 9,
  save: 10,
  restore: 11,
  transform: 12,
  moveTo: 13,
  lineTo: 14,
  curveTo: 15,
  curveTo2: 16,
  curveTo3: 17,
  closePath: 18,
  rectangle: 19,
  stroke: 20,
  closeStroke: 21,
  fill: 22,
  eoFill: 23,
  fillStroke: 24,
  eoFillStroke: 25,
  closeFillStroke: 26,
  closeEOFillStroke: 27,
  endPath: 28,
  clip: 29,
  eoClip: 30,
  beginText: 31,
  endText: 32,
  setCharSpacing: 33,
  setWordSpacing: 34,
  setHScale: 35,
  setLeading: 36,
  setFont: 37,
  setTextRenderingMode: 38,
  setTextRise: 39,
  moveText: 40,
  setLeadingMoveText: 41,
  setTextMatrix: 42,
  nextLine: 43,
  showText: 44,
  showSpacedText: 45,
  nextLineShowText: 46,
  nextLineSetSpacingShowText: 47,
  setCharWidth: 48,
  setCharWidthAndBounds: 49,
  setStrokeColorSpace: 50,
  setFillColorSpace: 51,
  setStrokeColor: 52,
  setStrokeColorN: 53,
  setFillColor: 54,
  setFillColorN: 55,
  setStrokeGray: 56,
  setFillGray: 57,
  setStrokeRGBColor: 58,
  setFillRGBColor: 59,
  setStrokeCMYKColor: 60,
  setFillCMYKColor: 61,
  shadingFill: 62,
  beginInlineImage: 63,
  beginImageData: 64,
  endInlineImage: 65,
  paintXObject: 66,
  markPoint: 67,
  markPointProps: 68,
  beginMarkedContent: 69,
  beginMarkedContentProps: 70,
  endMarkedContent: 71,
  beginCompat: 72,
  endCompat: 73,
  paintFormXObjectBegin: 74,
  paintFormXObjectEnd: 75,
  beginGroup: 76,
  endGroup: 77,
  beginAnnotations: 78,
  endAnnotations: 79,
  beginAnnotation: 80,
  endAnnotation: 81,
  paintJpegXObject: 82,
  paintImageMaskXObject: 83,
  paintImageMaskXObjectGroup: 84,
  paintImageXObject: 85,
  paintInlineImageXObject: 86,
  paintInlineImageXObjectGroup: 87,
  paintImageXObjectRepeat: 88,
  paintImageMaskXObjectRepeat: 89,
  paintSolidColorImageMask: 90,
  constructPath: 91
};

// A notice for devs. These are good for things that are helpful to devs, such
// as warning that Workers were disabled, which is important to devs but not
// end users.
function info(msg) {
  if (PDFJS.verbosity >= PDFJS.VERBOSITY_LEVELS.infos) {
    console.log('Info: ' + msg);
  }
}

// Non-fatal warnings.
function warn(msg) {
  if (PDFJS.verbosity >= PDFJS.VERBOSITY_LEVELS.warnings) {
    console.log('Warning: ' + msg);
  }
}

// Deprecated API function -- treated as warnings.
function deprecated(details) {
  warn('Deprecated API usage: ' + details);
}

// Fatal errors that should trigger the fallback UI and halt execution by
// throwing an exception.
function error(msg) {
  if (PDFJS.verbosity >= PDFJS.VERBOSITY_LEVELS.errors) {
    console.log('Error: ' + msg);
    console.log(backtrace());
  }
  throw new Error(msg);
}

function backtrace() {
  try {
    throw new Error();
  } catch (e) {
    return e.stack ? e.stack.split('\n').slice(2).join('\n') : '';
  }
}

function assert(cond, msg) {
  if (!cond) {
    error(msg);
  }
}

var UNSUPPORTED_FEATURES = PDFJS.UNSUPPORTED_FEATURES = {
  unknown: 'unknown',
  forms: 'forms',
  javaScript: 'javaScript',
  smask: 'smask',
  shadingPattern: 'shadingPattern',
  font: 'font'
};

// Combines two URLs. The baseUrl shall be absolute URL. If the url is an
// absolute URL, it will be returned as is.
function combineUrl(baseUrl, url) {
  if (!url) {
    return baseUrl;
  }
  if (/^[a-z][a-z0-9+\-.]*:/i.test(url)) {
    return url;
  }
  var i;
  if (url.charAt(0) === '/') {
    // absolute path
    i = baseUrl.indexOf('://');
    if (url.charAt(1) === '/') {
      ++i;
    } else {
      i = baseUrl.indexOf('/', i + 3);
    }
    return baseUrl.substring(0, i) + url;
  } else {
    // relative path
    var pathLength = baseUrl.length;
    i = baseUrl.lastIndexOf('#');
    pathLength = i >= 0 ? i : pathLength;
    i = baseUrl.lastIndexOf('?', pathLength);
    pathLength = i >= 0 ? i : pathLength;
    var prefixLength = baseUrl.lastIndexOf('/', pathLength);
    return baseUrl.substring(0, prefixLength + 1) + url;
  }
}

// Validates if URL is safe and allowed, e.g. to avoid XSS.
function isValidUrl(url, allowRelative) {
  if (!url) {
    return false;
  }
  // RFC 3986 (http://tools.ietf.org/html/rfc3986#section-3.1)
  // scheme = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
  var protocol = /^[a-z][a-z0-9+\-.]*(?=:)/i.exec(url);
  if (!protocol) {
    return allowRelative;
  }
  protocol = protocol[0].toLowerCase();
  switch (protocol) {
    case 'http':
    case 'https':
    case 'ftp':
    case 'mailto':
    case 'tel':
      return true;
    default:
      return false;
  }
}
PDFJS.isValidUrl = isValidUrl;

function shadow(obj, prop, value) {
  Object.defineProperty(obj, prop, { value: value,
                                     enumerable: true,
                                     configurable: true,
                                     writable: false });
  return value;
}
PDFJS.shadow = shadow;

var LinkTarget = PDFJS.LinkTarget = {
  NONE: 0, // Default value.
  SELF: 1,
  BLANK: 2,
  PARENT: 3,
  TOP: 4,
};
var LinkTargetStringMap = [
  '',
  '_self',
  '_blank',
  '_parent',
  '_top'
];

function isExternalLinkTargetSet() {
//#if !MOZCENTRAL
  if (PDFJS.openExternalLinksInNewWindow) {
    deprecated('PDFJS.openExternalLinksInNewWindow, please use ' +
               '"PDFJS.externalLinkTarget = PDFJS.LinkTarget.BLANK" instead.');
    if (PDFJS.externalLinkTarget === LinkTarget.NONE) {
      PDFJS.externalLinkTarget = LinkTarget.BLANK;
    }
    // Reset the deprecated parameter, to suppress further warnings.
    PDFJS.openExternalLinksInNewWindow = false;
  }
//#endif
  switch (PDFJS.externalLinkTarget) {
    case LinkTarget.NONE:
      return false;
    case LinkTarget.SELF:
    case LinkTarget.BLANK:
    case LinkTarget.PARENT:
    case LinkTarget.TOP:
      return true;
  }
  warn('PDFJS.externalLinkTarget is invalid: ' + PDFJS.externalLinkTarget);
  // Reset the external link target, to suppress further warnings.
  PDFJS.externalLinkTarget = LinkTarget.NONE;
  return false;
}
PDFJS.isExternalLinkTargetSet = isExternalLinkTargetSet;

var PasswordResponses = PDFJS.PasswordResponses = {
  NEED_PASSWORD: 1,
  INCORRECT_PASSWORD: 2
};

var PasswordException = (function PasswordExceptionClosure() {
  function PasswordException(msg, code) {
    this.name = 'PasswordException';
    this.message = msg;
    this.code = code;
  }

  PasswordException.prototype = new Error();
  PasswordException.constructor = PasswordException;

  return PasswordException;
})();
PDFJS.PasswordException = PasswordException;

var UnknownErrorException = (function UnknownErrorExceptionClosure() {
  function UnknownErrorException(msg, details) {
    this.name = 'UnknownErrorException';
    this.message = msg;
    this.details = details;
  }

  UnknownErrorException.prototype = new Error();
  UnknownErrorException.constructor = UnknownErrorException;

  return UnknownErrorException;
})();
PDFJS.UnknownErrorException = UnknownErrorException;

var InvalidPDFException = (function InvalidPDFExceptionClosure() {
  function InvalidPDFException(msg) {
    this.name = 'InvalidPDFException';
    this.message = msg;
  }

  InvalidPDFException.prototype = new Error();
  InvalidPDFException.constructor = InvalidPDFException;

  return InvalidPDFException;
})();
PDFJS.InvalidPDFException = InvalidPDFException;

var MissingPDFException = (function MissingPDFExceptionClosure() {
  function MissingPDFException(msg) {
    this.name = 'MissingPDFException';
    this.message = msg;
  }

  MissingPDFException.prototype = new Error();
  MissingPDFException.constructor = MissingPDFException;

  return MissingPDFException;
})();
PDFJS.MissingPDFException = MissingPDFException;

var UnexpectedResponseException =
    (function UnexpectedResponseExceptionClosure() {
  function UnexpectedResponseException(msg, status) {
    this.name = 'UnexpectedResponseException';
    this.message = msg;
    this.status = status;
  }

  UnexpectedResponseException.prototype = new Error();
  UnexpectedResponseException.constructor = UnexpectedResponseException;

  return UnexpectedResponseException;
})();
PDFJS.UnexpectedResponseException = UnexpectedResponseException;

var NotImplementedException = (function NotImplementedExceptionClosure() {
  function NotImplementedException(msg) {
    this.message = msg;
  }

  NotImplementedException.prototype = new Error();
  NotImplementedException.prototype.name = 'NotImplementedException';
  NotImplementedException.constructor = NotImplementedException;

  return NotImplementedException;
})();

var MissingDataException = (function MissingDataExceptionClosure() {
  function MissingDataException(begin, end) {
    this.begin = begin;
    this.end = end;
    this.message = 'Missing data [' + begin + ', ' + end + ')';
  }

  MissingDataException.prototype = new Error();
  MissingDataException.prototype.name = 'MissingDataException';
  MissingDataException.constructor = MissingDataException;

  return MissingDataException;
})();

var XRefParseException = (function XRefParseExceptionClosure() {
  function XRefParseException(msg) {
    this.message = msg;
  }

  XRefParseException.prototype = new Error();
  XRefParseException.prototype.name = 'XRefParseException';
  XRefParseException.constructor = XRefParseException;

  return XRefParseException;
})();


function bytesToString(bytes) {
  assert(bytes !== null && typeof bytes === 'object' &&
         bytes.length !== undefined, 'Invalid argument for bytesToString');
  var length = bytes.length;
  var MAX_ARGUMENT_COUNT = 8192;
  if (length < MAX_ARGUMENT_COUNT) {
    return String.fromCharCode.apply(null, bytes);
  }
  var strBuf = [];
  for (var i = 0; i < length; i += MAX_ARGUMENT_COUNT) {
    var chunkEnd = Math.min(i + MAX_ARGUMENT_COUNT, length);
    var chunk = bytes.subarray(i, chunkEnd);
    strBuf.push(String.fromCharCode.apply(null, chunk));
  }
  return strBuf.join('');
}

function stringToBytes(str) {
  assert(typeof str === 'string', 'Invalid argument for stringToBytes');
  var length = str.length;
  var bytes = new Uint8Array(length);
  for (var i = 0; i < length; ++i) {
    bytes[i] = str.charCodeAt(i) & 0xFF;
  }
  return bytes;
}

function string32(value) {
  return String.fromCharCode((value >> 24) & 0xff, (value >> 16) & 0xff,
                             (value >> 8) & 0xff, value & 0xff);
}

function log2(x) {
  var n = 1, i = 0;
  while (x > n) {
    n <<= 1;
    i++;
  }
  return i;
}

function readInt8(data, start) {
  return (data[start] << 24) >> 24;
}

function readUint16(data, offset) {
  return (data[offset] << 8) | data[offset + 1];
}

function readUint32(data, offset) {
  return ((data[offset] << 24) | (data[offset + 1] << 16) |
         (data[offset + 2] << 8) | data[offset + 3]) >>> 0;
}

// Lazy test the endianness of the platform
// NOTE: This will be 'true' for simulated TypedArrays
function isLittleEndian() {
  var buffer8 = new Uint8Array(2);
  buffer8[0] = 1;
  var buffer16 = new Uint16Array(buffer8.buffer);
  return (buffer16[0] === 1);
}

Object.defineProperty(PDFJS, 'isLittleEndian', {
  configurable: true,
  get: function PDFJS_isLittleEndian() {
    return shadow(PDFJS, 'isLittleEndian', isLittleEndian());
  }
});

//#if !(FIREFOX || MOZCENTRAL || CHROME)
//// Lazy test if the userAgent support CanvasTypedArrays
function hasCanvasTypedArrays() {
  var canvas = document.createElement('canvas');
  canvas.width = canvas.height = 1;
  var ctx = canvas.getContext('2d');
  var imageData = ctx.createImageData(1, 1);
  return (typeof imageData.data.buffer !== 'undefined');
}

Object.defineProperty(PDFJS, 'hasCanvasTypedArrays', {
  configurable: true,
  get: function PDFJS_hasCanvasTypedArrays() {
    return shadow(PDFJS, 'hasCanvasTypedArrays', hasCanvasTypedArrays());
  }
});

var Uint32ArrayView = (function Uint32ArrayViewClosure() {

  function Uint32ArrayView(buffer, length) {
    this.buffer = buffer;
    this.byteLength = buffer.length;
    this.length = length === undefined ? (this.byteLength >> 2) : length;
    ensureUint32ArrayViewProps(this.length);
  }
  Uint32ArrayView.prototype = Object.create(null);

  var uint32ArrayViewSetters = 0;
  function createUint32ArrayProp(index) {
    return {
      get: function () {
        var buffer = this.buffer, offset = index << 2;
        return (buffer[offset] | (buffer[offset + 1] << 8) |
          (buffer[offset + 2] << 16) | (buffer[offset + 3] << 24)) >>> 0;
      },
      set: function (value) {
        var buffer = this.buffer, offset = index << 2;
        buffer[offset] = value & 255;
        buffer[offset + 1] = (value >> 8) & 255;
        buffer[offset + 2] = (value >> 16) & 255;
        buffer[offset + 3] = (value >>> 24) & 255;
      }
    };
  }

  function ensureUint32ArrayViewProps(length) {
    while (uint32ArrayViewSetters < length) {
      Object.defineProperty(Uint32ArrayView.prototype,
        uint32ArrayViewSetters,
        createUint32ArrayProp(uint32ArrayViewSetters));
      uint32ArrayViewSetters++;
    }
  }

  return Uint32ArrayView;
})();
//#else
//PDFJS.hasCanvasTypedArrays = true;
//#endif

var IDENTITY_MATRIX = [1, 0, 0, 1, 0, 0];

var Util = PDFJS.Util = (function UtilClosure() {
  function Util() {}

  var rgbBuf = ['rgb(', 0, ',', 0, ',', 0, ')'];

  // makeCssRgb() can be called thousands of times. Using |rgbBuf| avoids
  // creating many intermediate strings.
  Util.makeCssRgb = function Util_makeCssRgb(r, g, b) {
    rgbBuf[1] = r;
    rgbBuf[3] = g;
    rgbBuf[5] = b;
    return rgbBuf.join('');
  };

  // Concatenates two transformation matrices together and returns the result.
  Util.transform = function Util_transform(m1, m2) {
    return [
      m1[0] * m2[0] + m1[2] * m2[1],
      m1[1] * m2[0] + m1[3] * m2[1],
      m1[0] * m2[2] + m1[2] * m2[3],
      m1[1] * m2[2] + m1[3] * m2[3],
      m1[0] * m2[4] + m1[2] * m2[5] + m1[4],
      m1[1] * m2[4] + m1[3] * m2[5] + m1[5]
    ];
  };

  // For 2d affine transforms
  Util.applyTransform = function Util_applyTransform(p, m) {
    var xt = p[0] * m[0] + p[1] * m[2] + m[4];
    var yt = p[0] * m[1] + p[1] * m[3] + m[5];
    return [xt, yt];
  };

  Util.applyInverseTransform = function Util_applyInverseTransform(p, m) {
    var d = m[0] * m[3] - m[1] * m[2];
    var xt = (p[0] * m[3] - p[1] * m[2] + m[2] * m[5] - m[4] * m[3]) / d;
    var yt = (-p[0] * m[1] + p[1] * m[0] + m[4] * m[1] - m[5] * m[0]) / d;
    return [xt, yt];
  };

  // Applies the transform to the rectangle and finds the minimum axially
  // aligned bounding box.
  Util.getAxialAlignedBoundingBox =
    function Util_getAxialAlignedBoundingBox(r, m) {

    var p1 = Util.applyTransform(r, m);
    var p2 = Util.applyTransform(r.slice(2, 4), m);
    var p3 = Util.applyTransform([r[0], r[3]], m);
    var p4 = Util.applyTransform([r[2], r[1]], m);
    return [
      Math.min(p1[0], p2[0], p3[0], p4[0]),
      Math.min(p1[1], p2[1], p3[1], p4[1]),
      Math.max(p1[0], p2[0], p3[0], p4[0]),
      Math.max(p1[1], p2[1], p3[1], p4[1])
    ];
  };

  Util.inverseTransform = function Util_inverseTransform(m) {
    var d = m[0] * m[3] - m[1] * m[2];
    return [m[3] / d, -m[1] / d, -m[2] / d, m[0] / d,
      (m[2] * m[5] - m[4] * m[3]) / d, (m[4] * m[1] - m[5] * m[0]) / d];
  };

  // Apply a generic 3d matrix M on a 3-vector v:
  //   | a b c |   | X |
  //   | d e f | x | Y |
  //   | g h i |   | Z |
  // M is assumed to be serialized as [a,b,c,d,e,f,g,h,i],
  // with v as [X,Y,Z]
  Util.apply3dTransform = function Util_apply3dTransform(m, v) {
    return [
      m[0] * v[0] + m[1] * v[1] + m[2] * v[2],
      m[3] * v[0] + m[4] * v[1] + m[5] * v[2],
      m[6] * v[0] + m[7] * v[1] + m[8] * v[2]
    ];
  };

  // This calculation uses Singular Value Decomposition.
  // The SVD can be represented with formula A = USV. We are interested in the
  // matrix S here because it represents the scale values.
  Util.singularValueDecompose2dScale =
    function Util_singularValueDecompose2dScale(m) {

    var transpose = [m[0], m[2], m[1], m[3]];

    // Multiply matrix m with its transpose.
    var a = m[0] * transpose[0] + m[1] * transpose[2];
    var b = m[0] * transpose[1] + m[1] * transpose[3];
    var c = m[2] * transpose[0] + m[3] * transpose[2];
    var d = m[2] * transpose[1] + m[3] * transpose[3];

    // Solve the second degree polynomial to get roots.
    var first = (a + d) / 2;
    var second = Math.sqrt((a + d) * (a + d) - 4 * (a * d - c * b)) / 2;
    var sx = first + second || 1;
    var sy = first - second || 1;

    // Scale values are the square roots of the eigenvalues.
    return [Math.sqrt(sx), Math.sqrt(sy)];
  };

  // Normalize rectangle rect=[x1, y1, x2, y2] so that (x1,y1) < (x2,y2)
  // For coordinate systems whose origin lies in the bottom-left, this
  // means normalization to (BL,TR) ordering. For systems with origin in the
  // top-left, this means (TL,BR) ordering.
  Util.normalizeRect = function Util_normalizeRect(rect) {
    var r = rect.slice(0); // clone rect
    if (rect[0] > rect[2]) {
      r[0] = rect[2];
      r[2] = rect[0];
    }
    if (rect[1] > rect[3]) {
      r[1] = rect[3];
      r[3] = rect[1];
    }
    return r;
  };

  // Returns a rectangle [x1, y1, x2, y2] corresponding to the
  // intersection of rect1 and rect2. If no intersection, returns 'false'
  // The rectangle coordinates of rect1, rect2 should be [x1, y1, x2, y2]
  Util.intersect = function Util_intersect(rect1, rect2) {
    function compare(a, b) {
      return a - b;
    }

    // Order points along the axes
    var orderedX = [rect1[0], rect1[2], rect2[0], rect2[2]].sort(compare),
        orderedY = [rect1[1], rect1[3], rect2[1], rect2[3]].sort(compare),
        result = [];

    rect1 = Util.normalizeRect(rect1);
    rect2 = Util.normalizeRect(rect2);

    // X: first and second points belong to different rectangles?
    if ((orderedX[0] === rect1[0] && orderedX[1] === rect2[0]) ||
        (orderedX[0] === rect2[0] && orderedX[1] === rect1[0])) {
      // Intersection must be between second and third points
      result[0] = orderedX[1];
      result[2] = orderedX[2];
    } else {
      return false;
    }

    // Y: first and second points belong to different rectangles?
    if ((orderedY[0] === rect1[1] && orderedY[1] === rect2[1]) ||
        (orderedY[0] === rect2[1] && orderedY[1] === rect1[1])) {
      // Intersection must be between second and third points
      result[1] = orderedY[1];
      result[3] = orderedY[2];
    } else {
      return false;
    }

    return result;
  };

  Util.sign = function Util_sign(num) {
    return num < 0 ? -1 : 1;
  };

  Util.appendToArray = function Util_appendToArray(arr1, arr2) {
    Array.prototype.push.apply(arr1, arr2);
  };

  Util.prependToArray = function Util_prependToArray(arr1, arr2) {
    Array.prototype.unshift.apply(arr1, arr2);
  };

  Util.extendObj = function extendObj(obj1, obj2) {
    for (var key in obj2) {
      obj1[key] = obj2[key];
    }
  };

  Util.getInheritableProperty = function Util_getInheritableProperty(dict,
                                                                     name) {
    while (dict && !dict.has(name)) {
      dict = dict.get('Parent');
    }
    if (!dict) {
      return null;
    }
    return dict.get(name);
  };

  Util.inherit = function Util_inherit(sub, base, prototype) {
    sub.prototype = Object.create(base.prototype);
    sub.prototype.constructor = sub;
    for (var prop in prototype) {
      sub.prototype[prop] = prototype[prop];
    }
  };

  Util.loadScript = function Util_loadScript(src, callback) {
    var script = document.createElement('script');
    var loaded = false;
    script.setAttribute('src', src);
    if (callback) {
      script.onload = function() {
        if (!loaded) {
          callback();
        }
        loaded = true;
      };
    }
    document.getElementsByTagName('head')[0].appendChild(script);
  };

  return Util;
})();

/**
 * PDF page viewport created based on scale, rotation and offset.
 * @class
 * @alias PDFJS.PageViewport
 */
var PageViewport = PDFJS.PageViewport = (function PageViewportClosure() {
  /**
   * @constructor
   * @private
   * @param viewBox {Array} xMin, yMin, xMax and yMax coordinates.
   * @param scale {number} scale of the viewport.
   * @param rotation {number} rotations of the viewport in degrees.
   * @param offsetX {number} offset X
   * @param offsetY {number} offset Y
   * @param dontFlip {boolean} if true, axis Y will not be flipped.
   */
  function PageViewport(viewBox, scale, rotation, offsetX, offsetY, dontFlip) {
    this.viewBox = viewBox;
    this.scale = scale;
    this.rotation = rotation;
    this.offsetX = offsetX;
    this.offsetY = offsetY;

    // creating transform to convert pdf coordinate system to the normal
    // canvas like coordinates taking in account scale and rotation
    var centerX = (viewBox[2] + viewBox[0]) / 2;
    var centerY = (viewBox[3] + viewBox[1]) / 2;
    var rotateA, rotateB, rotateC, rotateD;
    rotation = rotation % 360;
    rotation = rotation < 0 ? rotation + 360 : rotation;
    switch (rotation) {
      case 180:
        rotateA = -1; rotateB = 0; rotateC = 0; rotateD = 1;
        break;
      case 90:
        rotateA = 0; rotateB = 1; rotateC = 1; rotateD = 0;
        break;
      case 270:
        rotateA = 0; rotateB = -1; rotateC = -1; rotateD = 0;
        break;
      //case 0:
      default:
        rotateA = 1; rotateB = 0; rotateC = 0; rotateD = -1;
        break;
    }

    if (dontFlip) {
      rotateC = -rotateC; rotateD = -rotateD;
    }

    var offsetCanvasX, offsetCanvasY;
    var width, height;
    if (rotateA === 0) {
      offsetCanvasX = Math.abs(centerY - viewBox[1]) * scale + offsetX;
      offsetCanvasY = Math.abs(centerX - viewBox[0]) * scale + offsetY;
      width = Math.abs(viewBox[3] - viewBox[1]) * scale;
      height = Math.abs(viewBox[2] - viewBox[0]) * scale;
    } else {
      offsetCanvasX = Math.abs(centerX - viewBox[0]) * scale + offsetX;
      offsetCanvasY = Math.abs(centerY - viewBox[1]) * scale + offsetY;
      width = Math.abs(viewBox[2] - viewBox[0]) * scale;
      height = Math.abs(viewBox[3] - viewBox[1]) * scale;
    }
    // creating transform for the following operations:
    // translate(-centerX, -centerY), rotate and flip vertically,
    // scale, and translate(offsetCanvasX, offsetCanvasY)
    this.transform = [
      rotateA * scale,
      rotateB * scale,
      rotateC * scale,
      rotateD * scale,
      offsetCanvasX - rotateA * scale * centerX - rotateC * scale * centerY,
      offsetCanvasY - rotateB * scale * centerX - rotateD * scale * centerY
    ];

    this.width = width;
    this.height = height;
    this.fontScale = scale;
  }
  PageViewport.prototype = /** @lends PDFJS.PageViewport.prototype */ {
    /**
     * Clones viewport with additional properties.
     * @param args {Object} (optional) If specified, may contain the 'scale' or
     * 'rotation' properties to override the corresponding properties in
     * the cloned viewport.
     * @returns {PDFJS.PageViewport} Cloned viewport.
     */
    clone: function PageViewPort_clone(args) {
      args = args || {};
      var scale = 'scale' in args ? args.scale : this.scale;
      var rotation = 'rotation' in args ? args.rotation : this.rotation;
      return new PageViewport(this.viewBox.slice(), scale, rotation,
                              this.offsetX, this.offsetY, args.dontFlip);
    },
    /**
     * Converts PDF point to the viewport coordinates. For examples, useful for
     * converting PDF location into canvas pixel coordinates.
     * @param x {number} X coordinate.
     * @param y {number} Y coordinate.
     * @returns {Object} Object that contains 'x' and 'y' properties of the
     * point in the viewport coordinate space.
     * @see {@link convertToPdfPoint}
     * @see {@link convertToViewportRectangle}
     */
    convertToViewportPoint: function PageViewport_convertToViewportPoint(x, y) {
      return Util.applyTransform([x, y], this.transform);
    },
    /**
     * Converts PDF rectangle to the viewport coordinates.
     * @param rect {Array} xMin, yMin, xMax and yMax coordinates.
     * @returns {Array} Contains corresponding coordinates of the rectangle
     * in the viewport coordinate space.
     * @see {@link convertToViewportPoint}
     */
    convertToViewportRectangle:
      function PageViewport_convertToViewportRectangle(rect) {
      var tl = Util.applyTransform([rect[0], rect[1]], this.transform);
      var br = Util.applyTransform([rect[2], rect[3]], this.transform);
      return [tl[0], tl[1], br[0], br[1]];
    },
    /**
     * Converts viewport coordinates to the PDF location. For examples, useful
     * for converting canvas pixel location into PDF one.
     * @param x {number} X coordinate.
     * @param y {number} Y coordinate.
     * @returns {Object} Object that contains 'x' and 'y' properties of the
     * point in the PDF coordinate space.
     * @see {@link convertToViewportPoint}
     */
    convertToPdfPoint: function PageViewport_convertToPdfPoint(x, y) {
      return Util.applyInverseTransform([x, y], this.transform);
    }
  };
  return PageViewport;
})();

var PDFStringTranslateTable = [
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0x2D8, 0x2C7, 0x2C6, 0x2D9, 0x2DD, 0x2DB, 0x2DA, 0x2DC, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x2022, 0x2020, 0x2021, 0x2026, 0x2014,
  0x2013, 0x192, 0x2044, 0x2039, 0x203A, 0x2212, 0x2030, 0x201E, 0x201C,
  0x201D, 0x2018, 0x2019, 0x201A, 0x2122, 0xFB01, 0xFB02, 0x141, 0x152, 0x160,
  0x178, 0x17D, 0x131, 0x142, 0x153, 0x161, 0x17E, 0, 0x20AC
];

function stringToPDFString(str) {
  var i, n = str.length, strBuf = [];
  if (str[0] === '\xFE' && str[1] === '\xFF') {
    // UTF16BE BOM
    for (i = 2; i < n; i += 2) {
      strBuf.push(String.fromCharCode(
        (str.charCodeAt(i) << 8) | str.charCodeAt(i + 1)));
    }
  } else {
    for (i = 0; i < n; ++i) {
      var code = PDFStringTranslateTable[str.charCodeAt(i)];
      strBuf.push(code ? String.fromCharCode(code) : str.charAt(i));
    }
  }
  return strBuf.join('');
}

function stringToUTF8String(str) {
  return decodeURIComponent(escape(str));
}

function utf8StringToString(str) {
  return unescape(encodeURIComponent(str));
}

function isEmptyObj(obj) {
  for (var key in obj) {
    return false;
  }
  return true;
}

function isBool(v) {
  return typeof v === 'boolean';
}

function isInt(v) {
  return typeof v === 'number' && ((v | 0) === v);
}

function isNum(v) {
  return typeof v === 'number';
}

function isString(v) {
  return typeof v === 'string';
}

function isName(v) {
  return v instanceof Name;
}

function isCmd(v, cmd) {
  return v instanceof Cmd && (cmd === undefined || v.cmd === cmd);
}

function isDict(v, type) {
  if (!(v instanceof Dict)) {
    return false;
  }
  if (!type) {
    return true;
  }
  var dictType = v.get('Type');
  return isName(dictType) && dictType.name === type;
}

function isArray(v) {
  return v instanceof Array;
}

function isStream(v) {
  return typeof v === 'object' && v !== null && v.getBytes !== undefined;
}

function isArrayBuffer(v) {
  return typeof v === 'object' && v !== null && v.byteLength !== undefined;
}

function isRef(v) {
  return v instanceof Ref;
}

/**
 * Promise Capability object.
 *
 * @typedef {Object} PromiseCapability
 * @property {Promise} promise - A promise object.
 * @property {function} resolve - Fullfills the promise.
 * @property {function} reject - Rejects the promise.
 */

/**
 * Creates a promise capability object.
 * @alias PDFJS.createPromiseCapability
 *
 * @return {PromiseCapability} A capability object contains:
 * - a Promise, resolve and reject methods.
 */
function createPromiseCapability() {
  var capability = {};
  capability.promise = new Promise(function (resolve, reject) {
    capability.resolve = resolve;
    capability.reject = reject;
  });
  return capability;
}

PDFJS.createPromiseCapability = createPromiseCapability;

/**
 * Polyfill for Promises:
 * The following promise implementation tries to generally implement the
 * Promise/A+ spec. Some notable differences from other promise libaries are:
 * - There currently isn't a seperate deferred and promise object.
 * - Unhandled rejections eventually show an error if they aren't handled.
 *
 * Based off of the work in:
 * https://bugzilla.mozilla.org/show_bug.cgi?id=810490
 */
(function PromiseClosure() {
  if (globalScope.Promise) {
    // Promises existing in the DOM/Worker, checking presence of all/resolve
    if (typeof globalScope.Promise.all !== 'function') {
      globalScope.Promise.all = function (iterable) {
        var count = 0, results = [], resolve, reject;
        var promise = new globalScope.Promise(function (resolve_, reject_) {
          resolve = resolve_;
          reject = reject_;
        });
        iterable.forEach(function (p, i) {
          count++;
          p.then(function (result) {
            results[i] = result;
            count--;
            if (count === 0) {
              resolve(results);
            }
          }, reject);
        });
        if (count === 0) {
          resolve(results);
        }
        return promise;
      };
    }
    if (typeof globalScope.Promise.resolve !== 'function') {
      globalScope.Promise.resolve = function (value) {
        return new globalScope.Promise(function (resolve) { resolve(value); });
      };
    }
    if (typeof globalScope.Promise.reject !== 'function') {
      globalScope.Promise.reject = function (reason) {
        return new globalScope.Promise(function (resolve, reject) {
          reject(reason);
        });
      };
    }
    if (typeof globalScope.Promise.prototype.catch !== 'function') {
      globalScope.Promise.prototype.catch = function (onReject) {
        return globalScope.Promise.prototype.then(undefined, onReject);
      };
    }
    return;
  }
//#if !MOZCENTRAL
  var STATUS_PENDING = 0;
  var STATUS_RESOLVED = 1;
  var STATUS_REJECTED = 2;

  // In an attempt to avoid silent exceptions, unhandled rejections are
  // tracked and if they aren't handled in a certain amount of time an
  // error is logged.
  var REJECTION_TIMEOUT = 500;

  var HandlerManager = {
    handlers: [],
    running: false,
    unhandledRejections: [],
    pendingRejectionCheck: false,

    scheduleHandlers: function scheduleHandlers(promise) {
      if (promise._status === STATUS_PENDING) {
        return;
      }

      this.handlers = this.handlers.concat(promise._handlers);
      promise._handlers = [];

      if (this.running) {
        return;
      }
      this.running = true;

      setTimeout(this.runHandlers.bind(this), 0);
    },

    runHandlers: function runHandlers() {
      var RUN_TIMEOUT = 1; // ms
      var timeoutAt = Date.now() + RUN_TIMEOUT;
      while (this.handlers.length > 0) {
        var handler = this.handlers.shift();

        var nextStatus = handler.thisPromise._status;
        var nextValue = handler.thisPromise._value;

        try {
          if (nextStatus === STATUS_RESOLVED) {
            if (typeof handler.onResolve === 'function') {
              nextValue = handler.onResolve(nextValue);
            }
          } else if (typeof handler.onReject === 'function') {
              nextValue = handler.onReject(nextValue);
              nextStatus = STATUS_RESOLVED;

              if (handler.thisPromise._unhandledRejection) {
                this.removeUnhandeledRejection(handler.thisPromise);
              }
          }
        } catch (ex) {
          nextStatus = STATUS_REJECTED;
          nextValue = ex;
        }

        handler.nextPromise._updateStatus(nextStatus, nextValue);
        if (Date.now() >= timeoutAt) {
          break;
        }
      }

      if (this.handlers.length > 0) {
        setTimeout(this.runHandlers.bind(this), 0);
        return;
      }

      this.running = false;
    },

    addUnhandledRejection: function addUnhandledRejection(promise) {
      this.unhandledRejections.push({
        promise: promise,
        time: Date.now()
      });
      this.scheduleRejectionCheck();
    },

    removeUnhandeledRejection: function removeUnhandeledRejection(promise) {
      promise._unhandledRejection = false;
      for (var i = 0; i < this.unhandledRejections.length; i++) {
        if (this.unhandledRejections[i].promise === promise) {
          this.unhandledRejections.splice(i);
          i--;
        }
      }
    },

    scheduleRejectionCheck: function scheduleRejectionCheck() {
      if (this.pendingRejectionCheck) {
        return;
      }
      this.pendingRejectionCheck = true;
      setTimeout(function rejectionCheck() {
        this.pendingRejectionCheck = false;
        var now = Date.now();
        for (var i = 0; i < this.unhandledRejections.length; i++) {
          if (now - this.unhandledRejections[i].time > REJECTION_TIMEOUT) {
            var unhandled = this.unhandledRejections[i].promise._value;
            var msg = 'Unhandled rejection: ' + unhandled;
            if (unhandled.stack) {
              msg += '\n' + unhandled.stack;
            }
            warn(msg);
            this.unhandledRejections.splice(i);
            i--;
          }
        }
        if (this.unhandledRejections.length) {
          this.scheduleRejectionCheck();
        }
      }.bind(this), REJECTION_TIMEOUT);
    }
  };

  function Promise(resolver) {
    this._status = STATUS_PENDING;
    this._handlers = [];
    try {
      resolver.call(this, this._resolve.bind(this), this._reject.bind(this));
    } catch (e) {
      this._reject(e);
    }
  }
  /**
   * Builds a promise that is resolved when all the passed in promises are
   * resolved.
   * @param {array} array of data and/or promises to wait for.
   * @return {Promise} New dependant promise.
   */
  Promise.all = function Promise_all(promises) {
    var resolveAll, rejectAll;
    var deferred = new Promise(function (resolve, reject) {
      resolveAll = resolve;
      rejectAll = reject;
    });
    var unresolved = promises.length;
    var results = [];
    if (unresolved === 0) {
      resolveAll(results);
      return deferred;
    }
    function reject(reason) {
      if (deferred._status === STATUS_REJECTED) {
        return;
      }
      results = [];
      rejectAll(reason);
    }
    for (var i = 0, ii = promises.length; i < ii; ++i) {
      var promise = promises[i];
      var resolve = (function(i) {
        return function(value) {
          if (deferred._status === STATUS_REJECTED) {
            return;
          }
          results[i] = value;
          unresolved--;
          if (unresolved === 0) {
            resolveAll(results);
          }
        };
      })(i);
      if (Promise.isPromise(promise)) {
        promise.then(resolve, reject);
      } else {
        resolve(promise);
      }
    }
    return deferred;
  };

  /**
   * Checks if the value is likely a promise (has a 'then' function).
   * @return {boolean} true if value is thenable
   */
  Promise.isPromise = function Promise_isPromise(value) {
    return value && typeof value.then === 'function';
  };

  /**
   * Creates resolved promise
   * @param value resolve value
   * @returns {Promise}
   */
  Promise.resolve = function Promise_resolve(value) {
    return new Promise(function (resolve) { resolve(value); });
  };

  /**
   * Creates rejected promise
   * @param reason rejection value
   * @returns {Promise}
   */
  Promise.reject = function Promise_reject(reason) {
    return new Promise(function (resolve, reject) { reject(reason); });
  };

  Promise.prototype = {
    _status: null,
    _value: null,
    _handlers: null,
    _unhandledRejection: null,

    _updateStatus: function Promise__updateStatus(status, value) {
      if (this._status === STATUS_RESOLVED ||
          this._status === STATUS_REJECTED) {
        return;
      }

      if (status === STATUS_RESOLVED &&
          Promise.isPromise(value)) {
        value.then(this._updateStatus.bind(this, STATUS_RESOLVED),
                   this._updateStatus.bind(this, STATUS_REJECTED));
        return;
      }

      this._status = status;
      this._value = value;

      if (status === STATUS_REJECTED && this._handlers.length === 0) {
        this._unhandledRejection = true;
        HandlerManager.addUnhandledRejection(this);
      }

      HandlerManager.scheduleHandlers(this);
    },

    _resolve: function Promise_resolve(value) {
      this._updateStatus(STATUS_RESOLVED, value);
    },

    _reject: function Promise_reject(reason) {
      this._updateStatus(STATUS_REJECTED, reason);
    },

    then: function Promise_then(onResolve, onReject) {
      var nextPromise = new Promise(function (resolve, reject) {
        this.resolve = resolve;
        this.reject = reject;
      });
      this._handlers.push({
        thisPromise: this,
        onResolve: onResolve,
        onReject: onReject,
        nextPromise: nextPromise
      });
      HandlerManager.scheduleHandlers(this);
      return nextPromise;
    },

    catch: function Promise_catch(onReject) {
      return this.then(undefined, onReject);
    }
  };

  globalScope.Promise = Promise;
//#else
//throw new Error('DOM Promise is not present');
//#endif
})();

var StatTimer = (function StatTimerClosure() {
  function rpad(str, pad, length) {
    while (str.length < length) {
      str += pad;
    }
    return str;
  }
  function StatTimer() {
    this.started = {};
    this.times = [];
    this.enabled = true;
  }
  StatTimer.prototype = {
    time: function StatTimer_time(name) {
      if (!this.enabled) {
        return;
      }
      if (name in this.started) {
        warn('Timer is already running for ' + name);
      }
      this.started[name] = Date.now();
    },
    timeEnd: function StatTimer_timeEnd(name) {
      if (!this.enabled) {
        return;
      }
      if (!(name in this.started)) {
        warn('Timer has not been started for ' + name);
      }
      this.times.push({
        'name': name,
        'start': this.started[name],
        'end': Date.now()
      });
      // Remove timer from started so it can be called again.
      delete this.started[name];
    },
    toString: function StatTimer_toString() {
      var i, ii;
      var times = this.times;
      var out = '';
      // Find the longest name for padding purposes.
      var longest = 0;
      for (i = 0, ii = times.length; i < ii; ++i) {
        var name = times[i]['name'];
        if (name.length > longest) {
          longest = name.length;
        }
      }
      for (i = 0, ii = times.length; i < ii; ++i) {
        var span = times[i];
        var duration = span.end - span.start;
        out += rpad(span['name'], ' ', longest) + ' ' + duration + 'ms\n';
      }
      return out;
    }
  };
  return StatTimer;
})();

PDFJS.createBlob = function createBlob(data, contentType) {
  if (typeof Blob !== 'undefined') {
    return new Blob([data], { type: contentType });
  }
  // Blob builder is deprecated in FF14 and removed in FF18.
  var bb = new MozBlobBuilder();
  bb.append(data);
  return bb.getBlob(contentType);
};

PDFJS.createObjectURL = (function createObjectURLClosure() {
  // Blob/createObjectURL is not available, falling back to data schema.
  var digits =
    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

  return function createObjectURL(data, contentType) {
    if (!PDFJS.disableCreateObjectURL &&
        typeof URL !== 'undefined' && URL.createObjectURL) {
      var blob = PDFJS.createBlob(data, contentType);
      return URL.createObjectURL(blob);
    }

    var buffer = 'data:' + contentType + ';base64,';
    for (var i = 0, ii = data.length; i < ii; i += 3) {
      var b1 = data[i] & 0xFF;
      var b2 = data[i + 1] & 0xFF;
      var b3 = data[i + 2] & 0xFF;
      var d1 = b1 >> 2, d2 = ((b1 & 3) << 4) | (b2 >> 4);
      var d3 = i + 1 < ii ? ((b2 & 0xF) << 2) | (b3 >> 6) : 64;
      var d4 = i + 2 < ii ? (b3 & 0x3F) : 64;
      buffer += digits[d1] + digits[d2] + digits[d3] + digits[d4];
    }
    return buffer;
  };
})();

function MessageHandler(sourceName, targetName, comObj) {
  this.sourceName = sourceName;
  this.targetName = targetName;
  this.comObj = comObj;
  this.callbackIndex = 1;
  this.postMessageTransfers = true;
  var callbacksCapabilities = this.callbacksCapabilities = {};
  var ah = this.actionHandler = {};

  this._onComObjOnMessage = function messageHandlerComObjOnMessage(event) {
    var data = event.data;
    if (data.targetName !== this.sourceName) {
      return;
    }
    if (data.isReply) {
      var callbackId = data.callbackId;
      if (data.callbackId in callbacksCapabilities) {
        var callback = callbacksCapabilities[callbackId];
        delete callbacksCapabilities[callbackId];
        if ('error' in data) {
          callback.reject(data.error);
        } else {
          callback.resolve(data.data);
        }
      } else {
        error('Cannot resolve callback ' + callbackId);
      }
    } else if (data.action in ah) {
      var action = ah[data.action];
      if (data.callbackId) {
        var sourceName = this.sourceName;
        var targetName = data.sourceName;
        Promise.resolve().then(function () {
          return action[0].call(action[1], data.data);
        }).then(function (result) {
          comObj.postMessage({
            sourceName: sourceName,
            targetName: targetName,
            isReply: true,
            callbackId: data.callbackId,
            data: result
          });
        }, function (reason) {
          if (reason instanceof Error) {
            // Serialize error to avoid "DataCloneError"
            reason = reason + '';
          }
          comObj.postMessage({
            sourceName: sourceName,
            targetName: targetName,
            isReply: true,
            callbackId: data.callbackId,
            error: reason
          });
        });
      } else {
        action[0].call(action[1], data.data);
      }
    } else {
      error('Unknown action from worker: ' + data.action);
    }
  }.bind(this);
  comObj.addEventListener('message', this._onComObjOnMessage);
}

MessageHandler.prototype = {
  on: function messageHandlerOn(actionName, handler, scope) {
    var ah = this.actionHandler;
    if (ah[actionName]) {
      error('There is already an actionName called "' + actionName + '"');
    }
    ah[actionName] = [handler, scope];
  },
  /**
   * Sends a message to the comObj to invoke the action with the supplied data.
   * @param {String} actionName Action to call.
   * @param {JSON} data JSON data to send.
   * @param {Array} [transfers] Optional list of transfers/ArrayBuffers
   */
  send: function messageHandlerSend(actionName, data, transfers) {
    var message = {
      sourceName: this.sourceName,
      targetName: this.targetName,
      action: actionName,
      data: data
    };
    this.postMessage(message, transfers);
  },
  /**
   * Sends a message to the comObj to invoke the action with the supplied data.
   * Expects that other side will callback with the response.
   * @param {String} actionName Action to call.
   * @param {JSON} data JSON data to send.
   * @param {Array} [transfers] Optional list of transfers/ArrayBuffers.
   * @returns {Promise} Promise to be resolved with response data.
   */
  sendWithPromise:
    function messageHandlerSendWithPromise(actionName, data, transfers) {
    var callbackId = this.callbackIndex++;
    var message = {
      sourceName: this.sourceName,
      targetName: this.targetName,
      action: actionName,
      data: data,
      callbackId: callbackId
    };
    var capability = createPromiseCapability();
    this.callbacksCapabilities[callbackId] = capability;
    try {
      this.postMessage(message, transfers);
    } catch (e) {
      capability.reject(e);
    }
    return capability.promise;
  },
  /**
   * Sends raw message to the comObj.
   * @private
   * @param message {Object} Raw message.
   * @param transfers List of transfers/ArrayBuffers, or undefined.
   */
  postMessage: function (message, transfers) {
    if (transfers && this.postMessageTransfers) {
      this.comObj.postMessage(message, transfers);
    } else {
      this.comObj.postMessage(message);
    }
  },

  destroy: function () {
    this.comObj.removeEventListener('message', this._onComObjOnMessage);
  }
};

function loadJpegStream(id, imageUrl, objs) {
  var img = new Image();
  img.onload = (function loadJpegStream_onloadClosure() {
    objs.resolve(id, img);
  });
  img.onerror = (function loadJpegStream_onerrorClosure() {
    objs.resolve(id, null);
    warn('Error during JPEG image loading');
  });
  img.src = imageUrl;
}