[Files app] ES6 class for id3_parser.js

Bug: 778674
Change-Id: I210459cd62fca98836ad40f66bd011da4c412b5e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1646796
Auto-Submit: François Degros <fdegros@chromium.org>
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#666557}

ui/file_manager/file_manager/foreground/js/metadata/id3_parser.js

@@ -25,19 +25,17 @@ importScripts(
 
 /**
  * ID3 parser.
- *
- * @param {MetadataParserLogger} parent A metadata dispatcher.
- * @constructor
- * @struct
- * @extends {MetadataParser}
+ * @final
  */
-function Id3Parser(parent) {
-  MetadataParser.call(this, parent, 'id3', /\.(mp3)$/i);
-}
-
-Id3Parser.prototype.__proto__ = MetadataParser.prototype;
+class Id3Parser extends MetadataParser {
+  /**
+   * @param {!MetadataParserLogger} parent A metadata dispatcher.
+   */
+  constructor(parent) {
+    super(parent, 'id3', /\.(mp3)$/i);
+  }
 
-/**
+  /**
    * Reads synchsafe integer.
    * 'SynchSafe' term is taken from id3 documentation.
    *
@@ -46,7 +44,7 @@ Id3Parser.prototype.__proto__ = MetadataParser.prototype;
    * @return {number} Synchsafe value.
    * @private
    */
-Id3Parser.readSynchSafe_ = (reader, length) => {
+  static readSynchSafe_(reader, length) {
     let rv = 0;
 
     switch (length) {
@@ -61,20 +59,20 @@ Id3Parser.readSynchSafe_ = (reader, length) => {
     }
 
     return rv;
-};
+  }
 
-/**
+  /**
    * Reads 3bytes integer.
    *
    * @param {ByteReader} reader Reader to use.
    * @return {number} Uint24 value.
    * @private
    */
-Id3Parser.readUInt24_ = reader => {
+  static readUInt24_(reader) {
     return reader.readScalar(2, false) << 16 | reader.readScalar(1, false);
-};
+  }
 
-/**
+  /**
    * Reads string from reader with specified encoding
    *
    * @param {ByteReader} reader Reader to use.
@@ -83,7 +81,7 @@ Id3Parser.readUInt24_ = reader => {
    * @return {string} String value.
    * @private
    */
-Id3Parser.prototype.readString_ = function(reader, encoding, size) {
+  readString_(reader, encoding, size) {
     switch (encoding) {
       case Id3Parser.v2.ENCODING.ISO_8859_1:
         return reader.readNullTerminatedString(size);
@@ -104,9 +102,9 @@ Id3Parser.prototype.readString_ = function(reader, encoding, size) {
         return '';
       }
     }
-};
+  }
 
-/**
+  /**
    * Reads text frame from reader.
    *
    * @param {ByteReader} reader Reader to use.
@@ -115,13 +113,12 @@ Id3Parser.prototype.readString_ = function(reader, encoding, size) {
    * @param {number} end Frame end position in reader.
    * @private
    */
-Id3Parser.prototype.readTextFrame_ = function(
-    reader, majorVersion, frame, end) {
+  readTextFrame_(reader, majorVersion, frame, end) {
     frame.encoding = reader.readScalar(1, false, end);
     frame.value = this.readString_(reader, frame.encoding, end - reader.tell());
-};
+  }
 
-/**
+  /**
    * Reads user defined text frame from reader.
    *
    * @param {ByteReader} reader Reader to use.
@@ -130,24 +127,23 @@ Id3Parser.prototype.readTextFrame_ = function(
    * @param {number} end Frame end position in reader.
    * @private
    */
-Id3Parser.prototype.readUserDefinedTextFrame_ = function(
-    reader, majorVersion, frame, end) {
+  readUserDefinedTextFrame_(reader, majorVersion, frame, end) {
     frame.encoding = reader.readScalar(1, false, end);
 
     frame.description =
         this.readString_(reader, frame.encoding, end - reader.tell());
 
     frame.value = this.readString_(reader, frame.encoding, end - reader.tell());
-};
+  }
 
-/**
+  /**
    * @param {ByteReader} reader Reader to use.
    * @param {number} majorVersion Major id3 version to use.
    * @param {Object} frame Frame so store data at.
    * @param {number} end Frame end position in reader.
    * @private
    */
-Id3Parser.prototype.readPIC_ = function(reader, majorVersion, frame, end) {
+  readPIC_(reader, majorVersion, frame, end) {
     frame.encoding = reader.readScalar(1, false, end);
     frame.format = reader.readNullTerminatedString(3, end - reader.tell());
     frame.pictureType = reader.readScalar(1, false, end);
@@ -160,16 +156,16 @@ Id3Parser.prototype.readPIC_ = function(reader, majorVersion, frame, end) {
     } else {
       frame.imageUrl = reader.readImage(end - reader.tell());
     }
-};
+  }
 
-/**
+  /**
    * @param {ByteReader} reader Reader to use.
    * @param {number} majorVersion Major id3 version to use.
    * @param {Object} frame Frame so store data at.
    * @param {number} end Frame end position in reader.
    * @private
    */
-Id3Parser.prototype.readAPIC_ = function(reader, majorVersion, frame, end) {
+  readAPIC_(reader, majorVersion, frame, end) {
     this.vlog('Extracting picture');
     frame.encoding = reader.readScalar(1, false, end);
     frame.mime = reader.readNullTerminatedString(end - reader.tell());
@@ -182,9 +178,9 @@ Id3Parser.prototype.readAPIC_ = function(reader, majorVersion, frame, end) {
     } else {
       frame.imageUrl = reader.readImage(end - reader.tell());
     }
-};
+  }
 
-/**
+  /**
    * Reads string from reader with specified encoding
    *
    * @param {ByteReader} reader Reader to use.
@@ -192,7 +188,7 @@ Id3Parser.prototype.readAPIC_ = function(reader, majorVersion, frame, end) {
    * @return {Object} Frame read.
    * @private
    */
-Id3Parser.prototype.readFrame_ = function(reader, majorVersion) {
+  readFrame_(reader, majorVersion) {
     if (reader.eof()) {
       return null;
     }
@@ -229,7 +225,8 @@ Id3Parser.prototype.readFrame_ = function(reader, majorVersion) {
         break;
     }
 
-  this.vlog('Found frame [' + frame.name + '] with size [' + frame.size + ']');
+    this.vlog(
+        'Found frame [' + frame.name + '] with size [' + frame.size + ']');
 
     if (Id3Parser.v2.HANDLERS[frame.name]) {
       Id3Parser.v2.HANDLERS[frame.name].call(
@@ -244,15 +241,15 @@ Id3Parser.prototype.readFrame_ = function(reader, majorVersion) {
     reader.seek(frame.size + frame.headerSize, ByteReader.SEEK_CUR);
 
     return frame;
-};
+  }
 
-/**
+  /**
    * @param {File} file File object to parse.
    * @param {Object} metadata Metadata object of the file.
    * @param {function(Object)} callback Success callback.
    * @param {function(string)} onError Error callback.
    */
-Id3Parser.prototype.parse = function(file, metadata, callback, onError) {
+  parse(file, metadata, callback, onError) {
     const self = this;
 
     this.log('Starting id3 parser for ' + file.name);
@@ -272,8 +269,8 @@ Id3Parser.prototype.parse = function(file, metadata, callback, onError) {
 
           /**
            * Attempts to extract ID3v1 tag from 128 bytes long ByteBuffer
-         * @param {File} file File which tags are being extracted. Could be used
-         *     for logging purposes.
+           * @param {File} file File which tags are being extracted. Could be
+           *     used for logging purposes.
            * @param {ByteReader} reader ByteReader of 128 bytes.
            */
           function extractId3v1(file, reader) {
@@ -431,8 +428,8 @@ Id3Parser.prototype.parse = function(file, metadata, callback, onError) {
     this.vlog('Passed argument : ' + file);
 
     metadataParser.start(file);
-};
-
+  }
+}
 
 /**
  * Metadata order to use for metadata generation