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

chrome/browser/resources/file_manager/js/metadata/mpeg_parser.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';
-
-/**
- * @param {MetadataDispatcher} parent Parent object.
- * @constructor
- */
-function MpegParser(parent) {
-  MetadataParser.call(this, parent, 'mpeg', /\.(mp4|m4v|m4a|mpe?g4?)$/i);
-  this.mimeType = 'video/mpeg';
-}
-
-MpegParser.prototype = {__proto__: MetadataParser.prototype};
-
-/**
- * Size of the atom header.
- */
-MpegParser.HEADER_SIZE = 8;
-
-/**
- * @param {ByteReader} br ByteReader instance.
- * @param {number=} opt_end End of atom position.
- * @return {number} Atom size.
- */
-MpegParser.readAtomSize = function(br, opt_end) {
-  var pos = br.tell();
-
-  if (opt_end) {
-    // Assert that opt_end <= buffer end.
-    // When supplied, opt_end is the end of the enclosing atom and is used to
-    // check the correct nesting.
-    br.validateRead(opt_end - pos);
-  }
-
-  var size = br.readScalar(4, false, opt_end);
-
-  if (size < MpegParser.HEADER_SIZE)
-    throw 'atom too short (' + size + ') @' + pos;
-
-  if (opt_end && pos + size > opt_end)
-    throw 'atom too long (' + size + '>' + (opt_end - pos) + ') @' + pos;
-
-  return size;
-};
-
-/**
- * @param {ByteReader} br ByteReader instance.
- * @param {number=} opt_end End of atom position.
- * @return {string} Atom name.
- */
-MpegParser.readAtomName = function(br, opt_end) {
-  return br.readString(4, opt_end).toLowerCase();
-};
-
-/**
- * @param {Object} metadata Metadata object.
- * @return {Object} Root of the parser tree.
- */
-MpegParser.createRootParser = function(metadata) {
-  function findParentAtom(atom, name) {
-    for (;;) {
-      atom = atom.parent;
-      if (!atom) return null;
-      if (atom.name == name) return atom;
-    }
-  }
-
-  function parseFtyp(br, atom) {
-    metadata.brand = br.readString(4, atom.end);
-  }
-
-  function parseMvhd(br, atom) {
-    var version = br.readScalar(4, false, atom.end);
-    var offset = (version == 0) ? 8 : 16;
-    br.seek(offset, ByteReader.SEEK_CUR);
-    var timescale = br.readScalar(4, false, atom.end);
-    var duration = br.readScalar(4, false, atom.end);
-    metadata.duration = duration / timescale;
-  }
-
-  function parseHdlr(br, atom) {
-    br.seek(8, ByteReader.SEEK_CUR);
-    findParentAtom(atom, 'trak').trackType = br.readString(4, atom.end);
-  }
-
-  function parseStsd(br, atom) {
-    var track = findParentAtom(atom, 'trak');
-    if (track && track.trackType == 'vide') {
-      br.seek(40, ByteReader.SEEK_CUR);
-      metadata.width = br.readScalar(2, false, atom.end);
-      metadata.height = br.readScalar(2, false, atom.end);
-    }
-  }
-
-  function parseDataString(name, br, atom) {
-    br.seek(8, ByteReader.SEEK_CUR);
-    metadata[name] = br.readString(atom.end - br.tell(), atom.end);
-  }
-
-  function parseCovr(br, atom) {
-    br.seek(8, ByteReader.SEEK_CUR);
-    metadata.thumbnailURL = br.readImage(atom.end - br.tell(), atom.end);
-  }
-
-  // 'meta' atom can occur at one of the several places in the file structure.
-  var parseMeta = {
-    ilst: {
-      '©nam': { data: parseDataString.bind(null, 'title') },
-      '©alb': { data: parseDataString.bind(null, 'album') },
-      '©art': { data: parseDataString.bind(null, 'artist') },
-      'covr': { data: parseCovr }
-    },
-    versioned: true
-  };
-
-  // main parser for the entire file structure.
-  return {
-    ftyp: parseFtyp,
-    moov: {
-      mvhd: parseMvhd,
-      trak: {
-        mdia: {
-          hdlr: parseHdlr,
-          minf: {
-            stbl: {
-              stsd: parseStsd
-            }
-          }
-        },
-        meta: parseMeta
-      },
-      udta: {
-        meta: parseMeta
-      },
-      meta: parseMeta
-    },
-    meta: parseMeta
-  };
-};
-
-/**
- *
- * @param {File} file File.
- * @param {Object} metadata Metadata.
- * @param {function(Object)} callback Success callback.
- * @param {function} onError Error callback.
- */
-MpegParser.prototype.parse = function(file, metadata, callback, onError) {
-  this.rootParser_ = MpegParser.createRootParser(metadata);
-
-  // Kick off the processing by reading the first atom's header.
-  this.requestRead(file, 0, MpegParser.HEADER_SIZE, null,
-      onError, callback.bind(null, metadata));
-};
-
-/**
- * @param {function(ByteReader, Object)|Object} parser Parser tree node.
- * @param {ByteReader} br ByteReader instance.
- * @param {Object} atom Atom descriptor.
- * @param {number} filePos File position of the atom start.
- */
-MpegParser.prototype.applyParser = function(parser, br, atom, filePos) {
-  if (this.verbose) {
-    var path = atom.name;
-    for (var p = atom.parent; p && p.name; p = p.parent) {
-      path = p.name + '.' + path;
-    }
-
-    var action;
-    if (!parser) {
-      action = 'skipping ';
-    } else if (parser instanceof Function) {
-      action = 'parsing  ';
-    } else {
-      action = 'recursing';
-    }
-
-    var start = atom.start - MpegParser.HEADER_SIZE;
-    this.vlog(path + ': ' +
-              '@' + (filePos + start) + ':' + (atom.end - start),
-              action);
-  }
-
-  if (parser) {
-    if (parser instanceof Function) {
-      br.pushSeek(atom.start);
-      parser(br, atom);
-      br.popSeek();
-    } else {
-      if (parser.versioned) {
-        atom.start += 4;
-      }
-      this.parseMpegAtomsInRange(parser, br, atom, filePos);
-    }
-  }
-};
-
-/**
- * @param {function(ByteReader, Object)|Object} parser Parser tree node.
- * @param {ByteReader} br ByteReader instance.
- * @param {Object} parentAtom Parent atom descriptor.
- * @param {number} filePos File position of the atom start.
- */
-MpegParser.prototype.parseMpegAtomsInRange = function(
-    parser, br, parentAtom, filePos) {
-  var count = 0;
-  for (var offset = parentAtom.start; offset != parentAtom.end;) {
-    if (count++ > 100) // Most likely we are looping through a corrupt file.
-      throw 'too many child atoms in ' + parentAtom.name + ' @' + offset;
-
-    br.seek(offset);
-    var size = MpegParser.readAtomSize(br, parentAtom.end);
-    var name = MpegParser.readAtomName(br, parentAtom.end);
-
-    this.applyParser(
-        parser[name],
-        br,
-        { start: offset + MpegParser.HEADER_SIZE,
-          end: offset + size,
-          name: name,
-          parent: parentAtom
-        },
-        filePos
-    );
-
-    offset += size;
-  }
-};
-
-/**
- * @param {File} file File.
- * @param {number} filePos Start position in the file.
- * @param {number} size Atom size.
- * @param {string} name Atom name.
- * @param {function} onError Error callback.
- * @param {function} onSuccess Success callback.
- */
-MpegParser.prototype.requestRead = function(
-    file, filePos, size, name, onError, onSuccess) {
-  var self = this;
-  var reader = new FileReader();
-  reader.onerror = onError;
-  reader.onload = function(event) {
-    self.processTopLevelAtom(
-        reader.result, file, filePos, size, name, onError, onSuccess);
-  };
-  this.vlog('reading @' + filePos + ':' + size);
-  reader.readAsArrayBuffer(file.slice(filePos, filePos + size));
-};
-
-/**
- * @param {ArrayBuffer} buf Data buffer.
- * @param {File} file File.
- * @param {number} filePos Start position in the file.
- * @param {number} size Atom size.
- * @param {string} name Atom name.
- * @param {function} onError Error callback.
- * @param {function} onSuccess Success callback.
- */
-MpegParser.prototype.processTopLevelAtom = function(
-    buf, file, filePos, size, name, onError, onSuccess) {
-  try {
-    var br = new ByteReader(buf);
-
-    // the header has already been read.
-    var atomEnd = size - MpegParser.HEADER_SIZE;
-
-    var bufLength = buf.byteLength;
-
-    // Check the available data size. It should be either exactly
-    // what we requested or HEADER_SIZE bytes less (for the last atom).
-    if (bufLength != atomEnd && bufLength != size) {
-      throw 'Read failure @' + filePos + ', ' +
-          'requested ' + size + ', read ' + bufLength;
-    }
-
-    // Process the top level atom.
-    if (name) { // name is null only the first time.
-      this.applyParser(
-          this.rootParser_[name],
-          br,
-          {start: 0, end: atomEnd, name: name},
-          filePos
-      );
-    }
-
-    filePos += bufLength;
-    if (bufLength == size) {
-      // The previous read returned everything we asked for, including
-      // the next atom header at the end of the buffer.
-      // Parse this header and schedule the next read.
-      br.seek(-MpegParser.HEADER_SIZE, ByteReader.SEEK_END);
-      var nextSize = MpegParser.readAtomSize(br);
-      var nextName = MpegParser.readAtomName(br);
-
-      // If we do not have a parser for the next atom, skip the content and
-      // read only the header (the one after the next).
-      if (!this.rootParser_[nextName]) {
-        filePos += nextSize - MpegParser.HEADER_SIZE;
-        nextSize = MpegParser.HEADER_SIZE;
-      }
-
-      this.requestRead(file, filePos, nextSize, nextName, onError, onSuccess);
-    } else {
-      // The previous read did not return the next atom header, EOF reached.
-      this.vlog('EOF @' + filePos);
-      onSuccess();
-    }
-  } catch (e) {
-    onError(e.toString());
-  }
-};
-
-MetadataDispatcher.registerParserClass(MpegParser);