[Files.app] Split the JavaScript files into subdirectories: common, background, and foreground

chrome/browser/resources/file_manager/js/image_editor/exif_encoder.js

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-'use strict';
-
-// TODO:(kaznacheev) Share the EXIF constants with exif_parser.js
-var EXIF_MARK_SOS = 0xffda;  // Start of "stream" (the actual image data).
-var EXIF_MARK_SOI = 0xffd8;  // Start of image data.
-var EXIF_MARK_EOI = 0xffd9;  // End of image data.
-
-var EXIF_MARK_APP0 = 0xffe0;  // APP0 block, most commonly JFIF data.
-var EXIF_MARK_EXIF = 0xffe1;  // Start of exif block.
-
-var EXIF_ALIGN_LITTLE = 0x4949;  // Indicates little endian exif data.
-var EXIF_ALIGN_BIG = 0x4d4d;  // Indicates big endian exif data.
-
-var EXIF_TAG_TIFF = 0x002a;  // First directory containing TIFF data.
-var EXIF_TAG_GPSDATA = 0x8825;  // Pointer from TIFF to the GPS directory.
-var EXIF_TAG_EXIFDATA = 0x8769;  // Pointer from TIFF to the EXIF IFD.
-
-var EXIF_TAG_JPG_THUMB_OFFSET = 0x0201;  // Pointer from TIFF to thumbnail.
-var EXIF_TAG_JPG_THUMB_LENGTH = 0x0202;  // Length of thumbnail data.
-
-var EXIF_TAG_IMAGE_WIDTH = 0x0100;
-var EXIF_TAG_IMAGE_HEIGHT = 0x0101;
-
-var EXIF_TAG_ORIENTATION = 0x0112;
-var EXIF_TAG_X_DIMENSION = 0xA002;
-var EXIF_TAG_Y_DIMENSION = 0xA003;
-
-/**
- * The Exif metadata encoder.
- * Uses the metadata format as defined by ExifParser.
- * @param {Object} original_metadata Metadata to encode.
- * @constructor
- * @extends {ImageEncoder.MetadataEncoder}
- */
-function ExifEncoder(original_metadata) {
-  ImageEncoder.MetadataEncoder.apply(this, arguments);
-
-  this.ifd_ = this.metadata_.ifd;
-  if (!this.ifd_)
-    this.ifd_ = this.metadata_.ifd = {};
-}
-
-ExifEncoder.prototype = {__proto__: ImageEncoder.MetadataEncoder.prototype};
-
-ImageEncoder.registerMetadataEncoder(ExifEncoder, 'image/jpeg');
-
-/**
- * @param {HTMLCanvasElement|Object} canvas Canvas or anything with
- *                                          width and height properties.
- */
-ExifEncoder.prototype.setImageData = function(canvas) {
-  var image = this.ifd_.image;
-  if (!image)
-    image = this.ifd_.image = {};
-
-  // Only update width/height in this directory if they are present.
-  if (image[EXIF_TAG_IMAGE_WIDTH] && image[EXIF_TAG_IMAGE_HEIGHT]) {
-    image[EXIF_TAG_IMAGE_WIDTH].value = canvas.width;
-    image[EXIF_TAG_IMAGE_HEIGHT].value = canvas.height;
-  }
-
-  var exif = this.ifd_.exif;
-  if (!exif)
-    exif = this.ifd_.exif = {};
-  ExifEncoder.findOrCreateTag(image, EXIF_TAG_EXIFDATA);
-  ExifEncoder.findOrCreateTag(exif, EXIF_TAG_X_DIMENSION).value = canvas.width;
-  ExifEncoder.findOrCreateTag(exif, EXIF_TAG_Y_DIMENSION).value = canvas.height;
-
-  this.metadata_.width = canvas.width;
-  this.metadata_.height = canvas.height;
-
-  // Always save in default orientation.
-  delete this.metadata_.imageTransform;
-  ExifEncoder.findOrCreateTag(image, EXIF_TAG_ORIENTATION).value = 1;
-};
-
-
-/**
- * @param {HTMLCanvasElement} canvas Thumbnail canvas.
- * @param {number} quality (0..1] Thumbnail encoding quality.
- */
-ExifEncoder.prototype.setThumbnailData = function(canvas, quality) {
-  // Empirical formula with reasonable behavior:
-  // 10K for 1Mpix, 30K for 5Mpix, 50K for 9Mpix and up.
-  var pixelCount = this.metadata_.width * this.metadata_.height;
-  var maxEncodedSize = 5000 * Math.min(10, 1 + pixelCount / 1000000);
-
-  var DATA_URL_PREFIX = 'data:' + this.mimeType + ';base64,';
-  var BASE64_BLOAT = 4 / 3;
-  var maxDataURLLength =
-      DATA_URL_PREFIX.length + Math.ceil(maxEncodedSize * BASE64_BLOAT);
-
-  for (;; quality *= 0.8) {
-    ImageEncoder.MetadataEncoder.prototype.setThumbnailData.call(
-        this, canvas, quality);
-    if (this.metadata_.thumbnailURL.length <= maxDataURLLength || quality < 0.2)
-      break;
-  }
-
-  if (this.metadata_.thumbnailURL.length <= maxDataURLLength) {
-    var thumbnail = this.ifd_.thumbnail;
-    if (!thumbnail)
-      thumbnail = this.ifd_.thumbnail = {};
-
-    ExifEncoder.findOrCreateTag(thumbnail, EXIF_TAG_IMAGE_WIDTH).value =
-        canvas.width;
-
-    ExifEncoder.findOrCreateTag(thumbnail, EXIF_TAG_IMAGE_HEIGHT).value =
-        canvas.height;
-
-    // The values for these tags will be set in ExifWriter.encode.
-    ExifEncoder.findOrCreateTag(thumbnail, EXIF_TAG_JPG_THUMB_OFFSET);
-    ExifEncoder.findOrCreateTag(thumbnail, EXIF_TAG_JPG_THUMB_LENGTH);
-
-    // Always save in default orientation.
-    ExifEncoder.findOrCreateTag(thumbnail, EXIF_TAG_ORIENTATION).value = 1;
-  } else {
-    console.warn(
-       'Thumbnail URL too long: ' + this.metadata_.thumbnailURL.length);
-    // Delete thumbnail ifd so that it is not written out to a file, but
-    // keep thumbnailURL for display purposes.
-    if (this.ifd_.thumbnail) {
-      delete this.ifd_.thumbnail;
-    }
-  }
-  delete this.metadata_.thumbnailTransform;
-};
-
-/**
- * Return a range where the metadata is (or should be) located.
- * @param {string} encodedImage Raw image data to look for metadata.
- * @return {Object} An object with from and to properties.
- */
-ExifEncoder.prototype.findInsertionRange = function(encodedImage) {
-  function getWord(pos) {
-    if (pos + 2 > encodedImage.length)
-      throw 'Reading past the buffer end @' + pos;
-    return encodedImage.charCodeAt(pos) << 8 | encodedImage.charCodeAt(pos + 1);
-  }
-
-  if (getWord(0) != EXIF_MARK_SOI)
-    throw new Error('Jpeg data starts from 0x' + getWord(0).toString(16));
-
-  var sectionStart = 2;
-
-  // Default: an empty range right after SOI.
-  // Will be returned in absence of APP0 or Exif sections.
-  var range = {from: sectionStart, to: sectionStart};
-
-  for (;;) {
-    var tag = getWord(sectionStart);
-
-    if (tag == EXIF_MARK_SOS)
-      break;
-
-    var nextSectionStart = sectionStart + 2 + getWord(sectionStart + 2);
-    if (nextSectionStart <= sectionStart ||
-        nextSectionStart > encodedImage.length)
-      throw new Error('Invalid section size in jpeg data');
-
-    if (tag == EXIF_MARK_APP0) {
-      // Assert that we have not seen the Exif section yet.
-      if (range.from != range.to)
-        throw new Error('APP0 section found after EXIF section');
-      // An empty range right after the APP0 segment.
-      range.from = range.to = nextSectionStart;
-    } else if (tag == EXIF_MARK_EXIF) {
-      // A range containing the existing EXIF section.
-      range.from = sectionStart;
-      range.to = nextSectionStart;
-    }
-    sectionStart = nextSectionStart;
-  }
-
-  return range;
-};
-
-/**
- * @return {ArrayBuffer} serialized metadata ready to write to an image file.
- */
-ExifEncoder.prototype.encode = function() {
-  var HEADER_SIZE = 10;
-
-  // Allocate the largest theoretically possible size.
-  var bytes = new Uint8Array(0x10000);
-
-  // Serialize header
-  var hw = new ByteWriter(bytes.buffer, 0, HEADER_SIZE);
-  hw.writeScalar(EXIF_MARK_EXIF, 2);
-  hw.forward('size', 2);
-  hw.writeString('Exif\0\0');  // Magic string.
-
-  // First serialize the content of the exif section.
-  // Use a ByteWriter starting at HEADER_SIZE offset so that tell() positions
-  // can be directly mapped to offsets as encoded in the dictionaries.
-  var bw = new ByteWriter(bytes.buffer, HEADER_SIZE);
-
-  if (this.metadata_.littleEndian) {
-    bw.setByteOrder(ByteWriter.LITTLE_ENDIAN);
-    bw.writeScalar(EXIF_ALIGN_LITTLE, 2);
-  } else {
-    bw.setByteOrder(ByteWriter.BIG_ENDIAN);
-    bw.writeScalar(EXIF_ALIGN_BIG, 2);
-  }
-
-  bw.writeScalar(EXIF_TAG_TIFF, 2);
-
-  bw.forward('image-dir', 4);  // The pointer should point right after itself.
-  bw.resolveOffset('image-dir');
-
-  ExifEncoder.encodeDirectory(bw, this.ifd_.image,
-      [EXIF_TAG_EXIFDATA, EXIF_TAG_GPSDATA], 'thumb-dir');
-
-  if (this.ifd_.exif) {
-    bw.resolveOffset(EXIF_TAG_EXIFDATA);
-    ExifEncoder.encodeDirectory(bw, this.ifd_.exif);
-  } else {
-    if (EXIF_TAG_EXIFDATA in this.ifd_.image)
-      throw new Error('Corrupt exif dictionary reference');
-  }
-
-  if (this.ifd_.gps) {
-    bw.resolveOffset(EXIF_TAG_GPSDATA);
-    ExifEncoder.encodeDirectory(bw, this.ifd_.gps);
-  } else {
-    if (EXIF_TAG_GPSDATA in this.ifd_.image)
-      throw new Error('Missing gps dictionary reference');
-  }
-
-  if (this.ifd_.thumbnail) {
-    bw.resolveOffset('thumb-dir');
-    ExifEncoder.encodeDirectory(
-        bw,
-        this.ifd_.thumbnail,
-        [EXIF_TAG_JPG_THUMB_OFFSET, EXIF_TAG_JPG_THUMB_LENGTH]);
-
-    var thumbnailDecoded =
-        ImageEncoder.decodeDataURL(this.metadata_.thumbnailURL);
-    bw.resolveOffset(EXIF_TAG_JPG_THUMB_OFFSET);
-    bw.resolve(EXIF_TAG_JPG_THUMB_LENGTH, thumbnailDecoded.length);
-    bw.writeString(thumbnailDecoded);
-  } else {
-    bw.resolve('thumb-dir', 0);
-  }
-
-  bw.checkResolved();
-
-  var totalSize = HEADER_SIZE + bw.tell();
-  hw.resolve('size', totalSize - 2);  // The marker is excluded.
-  hw.checkResolved();
-
-  var subarray = new Uint8Array(totalSize);
-  for (var i = 0; i != totalSize; i++) {
-    subarray[i] = bytes[i];
-  }
-  return subarray.buffer;
-};
-
-/*
- * Static methods.
- */
-
-/**
- * Write the contents of an IFD directory.
- * @param {ByteWriter} bw ByteWriter to use.
- * @param {Object} directory A directory map as created by ExifParser.
- * @param {Array} resolveLater An array of tag ids for which the values will be
- *                resolved later.
- * @param {string} nextDirPointer A forward key for the pointer to the next
- *                 directory. If omitted the pointer is set to 0.
- */
-ExifEncoder.encodeDirectory = function(
-    bw, directory, resolveLater, nextDirPointer) {
-
-  var longValues = [];
-
-  bw.forward('dir-count', 2);
-  var count = 0;
-
-  for (var key in directory) {
-    var tag = directory[key];
-    bw.writeScalar(tag.id, 2);
-    bw.writeScalar(tag.format, 2);
-    bw.writeScalar(tag.componentCount, 4);
-
-    var width = ExifEncoder.getComponentWidth(tag) * tag.componentCount;
-
-    if (resolveLater && (resolveLater.indexOf(tag.id) >= 0)) {
-      // The actual value depends on further computations.
-      if (tag.componentCount != 1 || width > 4)
-        throw new Error('Cannot forward the pointer for ' + tag.id);
-      bw.forward(tag.id, width);
-    } else if (width <= 4) {
-      // The value fits into 4 bytes, write it immediately.
-      ExifEncoder.writeValue(bw, tag);
-    } else {
-      // The value does not fit, forward the 4 byte offset to the actual value.
-      width = 4;
-      bw.forward(tag.id, width);
-      longValues.push(tag);
-    }
-    bw.skip(4 - width);  // Align so that the value take up exactly 4 bytes.
-    count++;
-  }
-
-  bw.resolve('dir-count', count);
-
-  if (nextDirPointer) {
-    bw.forward(nextDirPointer, 4);
-  } else {
-    bw.writeScalar(0, 4);
-  }
-
-  // Write out the long values and resolve pointers.
-  for (var i = 0; i != longValues.length; i++) {
-    var longValue = longValues[i];
-    bw.resolveOffset(longValue.id);
-    ExifEncoder.writeValue(bw, longValue);
-  }
-};
-
-/**
- * @param {{format:number, id:number}} tag EXIF tag object.
- * @return {number} Width in bytes of the data unit associated with this tag.
- * TODO(kaznacheev): Share with ExifParser?
- */
-ExifEncoder.getComponentWidth = function(tag) {
-  switch (tag.format) {
-    case 1:  // Byte
-    case 2:  // String
-    case 7:  // Undefined
-      return 1;
-
-    case 3:  // Short
-      return 2;
-
-    case 4:  // Long
-    case 9:  // Signed Long
-      return 4;
-
-    case 5:  // Rational
-    case 10:  // Signed Rational
-      return 8;
-
-    default:  // ???
-      console.warn('Unknown tag format 0x' +
-          Number(tag.id).toString(16) + ': ' + tag.format);
-      return 4;
-  }
-};
-
-/**
- * Writes out the tag value.
- * @param {ByteWriter} bw Writer to use.
- * @param {Object} tag Tag, which value to write.
- */
-ExifEncoder.writeValue = function(bw, tag) {
-  if (tag.format == 2) {  // String
-    if (tag.componentCount != tag.value.length) {
-      throw new Error(
-          'String size mismatch for 0x' + Number(tag.id).toString(16));
-    }
-    bw.writeString(tag.value);
-  } else {  // Scalar or rational
-    var width = ExifEncoder.getComponentWidth(tag);
-
-    var writeComponent = function(value, signed) {
-      if (width == 8) {
-        bw.writeScalar(value[0], 4, signed);
-        bw.writeScalar(value[1], 4, signed);
-      } else {
-        bw.writeScalar(value, width, signed);
-      }
-    };
-
-    var signed = (tag.format == 9 || tag.format == 10);
-    if (tag.componentCount == 1) {
-       writeComponent(tag.value, signed);
-    } else {
-      for (var i = 0; i != tag.componentCount; i++) {
-        writeComponent(tag.value[i], signed);
-      }
-    }
-  }
-};
-
-/**
- * @param {{Object.<number,Object>}} directory EXIF directory.
- * @param {number} id Tag id.
- * @param {number} format Tag format
- *                        (used in {@link ExifEncoder#getComponentWidth}).
- * @param {number} componentCount Number of components in this tag.
- * @return {{id:number, format:number, componentCount:number}}
- *     Tag found or created.
- */
-ExifEncoder.findOrCreateTag = function(directory, id, format, componentCount) {
-  if (!(id in directory)) {
-    directory[id] = {
-      id: id,
-      format: format || 3,  // Short
-      componentCount: componentCount || 1
-    };
-  }
-  return directory[id];
-};
-
-/**
- * ByteWriter class.
- * @param {ArrayBuffer} arrayBuffer Underlying buffer to use.
- * @param {number} offset Offset at which to start writing.
- * @param {number} length Maximum length to use.
- * @class
- * @constructor
- */
-function ByteWriter(arrayBuffer, offset, length) {
-  length = length || (arrayBuffer.byteLength - offset);
-  this.view_ = new DataView(arrayBuffer, offset, length);
-  this.littleEndian_ = false;
-  this.pos_ = 0;
-  this.forwards_ = {};
-}
-
-/**
- * Little endian byte order.
- * @type {number}
- */
-ByteWriter.LITTLE_ENDIAN = 0;
-
-/**
- * Bug endian byte order.
- * @type {number}
- */
-ByteWriter.BIG_ENDIAN = 1;
-
-/**
- * Set the byte ordering for future writes.
- * @param {number} order ByteOrder to use {ByteWriter.LITTLE_ENDIAN}
- *   or {ByteWriter.BIG_ENDIAN}.
- */
-ByteWriter.prototype.setByteOrder = function(order) {
-  this.littleEndian_ = (order == ByteWriter.LITTLE_ENDIAN);
-};
-
-/**
- * @return {number} the current write position.
- */
-ByteWriter.prototype.tell = function() { return this.pos_ };
-
-/**
- * Skips desired amount of bytes in output stream.
- * @param {number} count Byte count to skip.
- */
-ByteWriter.prototype.skip = function(count) {
-  this.validateWrite(count);
-  this.pos_ += count;
-};
-
-/**
- * Check if the buffer has enough room to read 'width' bytes. Throws an error
- * if it has not.
- * @param {number} width Amount of bytes to check.
- */
-ByteWriter.prototype.validateWrite = function(width) {
-  if (this.pos_ + width > this.view_.byteLength)
-    throw new Error('Writing past the end of the buffer');
-};
-
-/**
- * Writes scalar value to output stream.
- * @param {number} value Value to write.
- * @param {number} width Desired width of written value.
- * @param {boolean=} opt_signed True if value represents signed number.
- */
-ByteWriter.prototype.writeScalar = function(value, width, opt_signed) {
-  var method;
-// The below switch is so verbose for two reasons:
-// 1. V8 is faster on method names which are 'symbols'.
-// 2. Method names are discoverable by full text search.
-  switch (width) {
-    case 1:
-      method = opt_signed ? 'setInt8' : 'setUint8';
-      break;
-
-    case 2:
-      method = opt_signed ? 'setInt16' : 'setUint16';
-      break;
-
-    case 4:
-      method = opt_signed ? 'setInt32' : 'setUint32';
-      break;
-
-    case 8:
-      method = opt_signed ? 'setInt64' : 'setUint64';
-      break;
-
-    default:
-      throw new Error('Invalid width: ' + width);
-      break;
-  }
-
-  this.validateWrite(width);
-  this.view_[method](this.pos_, value, this.littleEndian_);
-  this.pos_ += width;
-};
-
-/**
- * Writes string.
- * @param {string} str String to write.
- */
-ByteWriter.prototype.writeString = function(str) {
-  this.validateWrite(str.length);
-  for (var i = 0; i != str.length; i++) {
-    this.view_.setUint8(this.pos_++, str.charCodeAt(i));
-  }
-};
-
-/**
- * Allocate the space for 'width' bytes for the value that will be set later.
- * To be followed by a 'resolve' call with the same key.
- * @param {string} key A key to identify the value.
- * @param {number} width Width of the value in bytes.
- */
-ByteWriter.prototype.forward = function(key, width) {
-  if (key in this.forwards_)
-    throw new Error('Duplicate forward key ' + key);
-  this.validateWrite(width);
-  this.forwards_[key] = {
-    pos: this.pos_,
-    width: width
-  };
-  this.pos_ += width;
-};
-
-/**
- * Set the value previously allocated with a 'forward' call.
- * @param {string} key A key to identify the value.
- * @param {number} value value to write in pre-allocated space.
- */
-ByteWriter.prototype.resolve = function(key, value) {
-  if (!(key in this.forwards_))
-    throw new Error('Undeclared forward key ' + key.toString(16));
-  var forward = this.forwards_[key];
-  var curPos = this.pos_;
-  this.pos_ = forward.pos;
-  this.writeScalar(value, forward.width);
-  this.pos_ = curPos;
-  delete this.forwards_[key];
-};
-
-/**
- * A shortcut to resolve the value to the current write position.
- * @param {string} key A key to identify pre-allocated position.
- */
-ByteWriter.prototype.resolveOffset = function(key) {
-  this.resolve(key, this.tell());
-};
-
-/**
- * Check if every forward has been resolved, throw and error if not.
- */
-ByteWriter.prototype.checkResolved = function() {
-  for (var key in this.forwards_) {
-    throw new Error('Unresolved forward pointer ' + key.toString(16));
-  }
-};