tracing/tracing/extras/importer/gzip_importer.html - external/trace-viewer - Git at Google

 <!DOCTYPE html>
 <!--
 Copyright (c) 2013 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.
 -->

 <link rel="import" href="/extras/importer/jszip.html">
 <link rel="import" href="/importer/importer.html">
 <link rel="import" href="/model/model.html">

 <script>
 'use strict';

 /**
  * @fileoverview GzipImporter inflates gzip compressed data and passes it along
  * to an actual importer.
  */
 tr.exportTo('tr.e.importer', function() {
   var Importer = tr.importer.Importer;

   var GZIP_MEMBER_HEADER_ID_SIZE = 3;

   var GZIP_HEADER_ID1 = 0x1f;
   var GZIP_HEADER_ID2 = 0x8b;
   var GZIP_DEFLATE_COMPRESSION = 8;

   function GzipImporter(model, eventData) {
     // Normalize the data into an Uint8Array.
     if (typeof(eventData) === 'string' || eventData instanceof String) {
       eventData = JSZip.utils.transformTo('uint8array', eventData);
     } else if (eventData instanceof ArrayBuffer) {
       eventData = new Uint8Array(eventData);
     } else
       throw new Error('Unknown gzip data format');
     this.model_ = model;
     this.gzipData_ = eventData;
   }

   /**
    * @param {eventData} Possibly gzip compressed data as a string or an
    *                    ArrayBuffer.
    * @return {boolean} Whether obj looks like gzip compressed data.
    */
   GzipImporter.canImport = function(eventData) {
     var header;
     if (eventData instanceof ArrayBuffer)
       header = new Uint8Array(eventData.slice(0, GZIP_MEMBER_HEADER_ID_SIZE));
     else if (typeof(eventData) === 'string' || eventData instanceof String) {
       header = eventData.substring(0, GZIP_MEMBER_HEADER_ID_SIZE);
       // Convert the string to a byteArray for correct value comparison.
       header = JSZip.utils.transformTo('uint8array', header);
     } else
       return false;
     return header[0] == GZIP_HEADER_ID1 &&
         header[1] == GZIP_HEADER_ID2 &&
         header[2] == GZIP_DEFLATE_COMPRESSION;
   };

   /**
    * Inflates (decompresses) the data stored in the given gzip bitstream.
    * @return {string} Inflated data.
    */
   GzipImporter.inflateGzipData_ = function(data) {
     var position = 0;

     function getByte() {
       if (position >= data.length)
         throw new Error('Unexpected end of gzip data');
       return data[position++];
     }

     function getWord() {
       var low = getByte();
       var high = getByte();
       return (high << 8) + low;
     }

     function skipBytes(amount) {
       position += amount;
     }

     function skipZeroTerminatedString() {
       while (getByte() != 0) {}
     }

     var id1 = getByte();
     var id2 = getByte();
     if (id1 !== GZIP_HEADER_ID1 || id2 !== GZIP_HEADER_ID2)
       throw new Error('Not gzip data');
     var compression_method = getByte();
     if (compression_method !== GZIP_DEFLATE_COMPRESSION)
       throw new Error('Unsupported compression method: ' + compression_method);
     var flags = getByte();
     var have_header_crc = flags & (1 << 1);
     var have_extra_fields = flags & (1 << 2);
     var have_file_name = flags & (1 << 3);
     var have_comment = flags & (1 << 4);

     // Skip modification time, extra flags and OS.
     skipBytes(4 + 1 + 1);

     // Skip remaining fields before compressed data.
     if (have_extra_fields) {
       var bytes_to_skip = getWord();
       skipBytes(bytes_to_skip);
     }
     if (have_file_name)
       skipZeroTerminatedString();
     if (have_comment)
       skipZeroTerminatedString();
     if (have_header_crc)
       getWord();

     // Inflate the data using jszip.
     var inflated_data =
         JSZip.compressions['DEFLATE'].uncompress(data.subarray(position));
     return JSZip.utils.transformTo('string', inflated_data);
   },

   GzipImporter.prototype = {
     __proto__: Importer.prototype,

     /**
      * Called by the Model to check whether the importer just encapsulates
      * the actual trace data which needs to be imported by another importer.
      */
     isTraceDataContainer: function() {
       return true;
     },

     /**
      * Called by the Model to extract subtraces from the event data. The
      * subtraces are passed on to other importers that can recognize them.
      */
     extractSubtraces: function() {
       var eventData = GzipImporter.inflateGzipData_(this.gzipData_);
       return eventData ? [eventData] : [];
     }
   };

   tr.importer.Importer.register(GzipImporter);

   return {
     GzipImporter: GzipImporter
   };
 });
 </script>
	<!DOCTYPE html>
	<!--
	Copyright (c) 2013 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.
	-->

	<link rel="import" href="/extras/importer/jszip.html">
	<link rel="import" href="/importer/importer.html">
	<link rel="import" href="/model/model.html">

	<script>
	'use strict';

	/**
	* @fileoverview GzipImporter inflates gzip compressed data and passes it along
	* to an actual importer.
	*/
	tr.exportTo('tr.e.importer', function() {
	var Importer = tr.importer.Importer;

	var GZIP_MEMBER_HEADER_ID_SIZE = 3;

	var GZIP_HEADER_ID1 = 0x1f;
	var GZIP_HEADER_ID2 = 0x8b;
	var GZIP_DEFLATE_COMPRESSION = 8;

	function GzipImporter(model, eventData) {
	// Normalize the data into an Uint8Array.
	if (typeof(eventData) === 'string' \|\| eventData instanceof String) {
	eventData = JSZip.utils.transformTo('uint8array', eventData);
	} else if (eventData instanceof ArrayBuffer) {
	eventData = new Uint8Array(eventData);
	} else
	throw new Error('Unknown gzip data format');
	this.model_ = model;
	this.gzipData_ = eventData;
	}

	/**
	* @param {eventData} Possibly gzip compressed data as a string or an
	* ArrayBuffer.
	* @return {boolean} Whether obj looks like gzip compressed data.
	*/
	GzipImporter.canImport = function(eventData) {
	var header;
	if (eventData instanceof ArrayBuffer)
	header = new Uint8Array(eventData.slice(0, GZIP_MEMBER_HEADER_ID_SIZE));
	else if (typeof(eventData) === 'string' \|\| eventData instanceof String) {
	header = eventData.substring(0, GZIP_MEMBER_HEADER_ID_SIZE);
	// Convert the string to a byteArray for correct value comparison.
	header = JSZip.utils.transformTo('uint8array', header);
	} else
	return false;
	return header[0] == GZIP_HEADER_ID1 &&
	header[1] == GZIP_HEADER_ID2 &&
	header[2] == GZIP_DEFLATE_COMPRESSION;
	};

	/**
	* Inflates (decompresses) the data stored in the given gzip bitstream.
	* @return {string} Inflated data.
	*/
	GzipImporter.inflateGzipData_ = function(data) {
	var position = 0;

	function getByte() {
	if (position >= data.length)
	throw new Error('Unexpected end of gzip data');
	return data[position++];
	}

	function getWord() {
	var low = getByte();
	var high = getByte();
	return (high << 8) + low;
	}

	function skipBytes(amount) {
	position += amount;
	}

	function skipZeroTerminatedString() {
	while (getByte() != 0) {}
	}

	var id1 = getByte();
	var id2 = getByte();
	if (id1 !== GZIP_HEADER_ID1 \|\| id2 !== GZIP_HEADER_ID2)
	throw new Error('Not gzip data');
	var compression_method = getByte();
	if (compression_method !== GZIP_DEFLATE_COMPRESSION)
	throw new Error('Unsupported compression method: ' + compression_method);
	var flags = getByte();
	var have_header_crc = flags & (1 << 1);
	var have_extra_fields = flags & (1 << 2);
	var have_file_name = flags & (1 << 3);
	var have_comment = flags & (1 << 4);

	// Skip modification time, extra flags and OS.
	skipBytes(4 + 1 + 1);

	// Skip remaining fields before compressed data.
	if (have_extra_fields) {
	var bytes_to_skip = getWord();
	skipBytes(bytes_to_skip);
	}
	if (have_file_name)
	skipZeroTerminatedString();
	if (have_comment)
	skipZeroTerminatedString();
	if (have_header_crc)
	getWord();

	// Inflate the data using jszip.
	var inflated_data =
	JSZip.compressions['DEFLATE'].uncompress(data.subarray(position));
	return JSZip.utils.transformTo('string', inflated_data);
	},

	GzipImporter.prototype = {
	__proto__: Importer.prototype,

	/**
	* Called by the Model to check whether the importer just encapsulates
	* the actual trace data which needs to be imported by another importer.
	*/
	isTraceDataContainer: function() {
	return true;
	},

	/**
	* Called by the Model to extract subtraces from the event data. The
	* subtraces are passed on to other importers that can recognize them.
	*/
	extractSubtraces: function() {
	var eventData = GzipImporter.inflateGzipData_(this.gzipData_);
	return eventData ? [eventData] : [];
	}
	};

	tr.importer.Importer.register(GzipImporter);

	return {
	GzipImporter: GzipImporter
	};
	});
	</script>