The Tor Browser: content/media/test/cancellable_request.sjs@97036ab72558 (annotated)

content/media/test/cancellable_request.sjs@97036ab72558 (annotated)

content/media/test/cancellable_request.sjs

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 function parseQuery(request, key) {
   var params = request.queryString.split('&');
   for (var j = 0; j < params.length; ++j) {
     var p = params[j];
 	if (p == key)
 	  return true;
     if (p.indexOf(key + "=") == 0)
 	  return p.substring(key.length + 1);
 	if (p.indexOf("=") < 0 && key == "")
 	  return p;
   }
   return false;
 }
 function push32BE(array, input) {
   array.push(String.fromCharCode((input >> 24) & 0xff));
   array.push(String.fromCharCode((input >> 16) & 0xff));
   array.push(String.fromCharCode((input >> 8) & 0xff));
   array.push(String.fromCharCode((input) & 0xff));
 }
 function push32LE(array, input) {
   array.push(String.fromCharCode((input) & 0xff));
   array.push(String.fromCharCode((input >> 8) & 0xff));
   array.push(String.fromCharCode((input >> 16) & 0xff));
   array.push(String.fromCharCode((input >> 24) & 0xff));
 }
 function push16LE(array, input) {
   array.push(String.fromCharCode((input) & 0xff));
   array.push(String.fromCharCode((input >> 8) & 0xff));
 }
 function buildWave(samples, sample_rate) {
   const RIFF_MAGIC = 0x52494646;
   const WAVE_MAGIC = 0x57415645;
   const FRMT_MAGIC = 0x666d7420;
   const DATA_MAGIC = 0x64617461;
   const RIFF_SIZE = 44;
   var header = [];
   push32BE(header, RIFF_MAGIC);
   push32LE(header, RIFF_SIZE + samples.length * 2);
   push32BE(header, WAVE_MAGIC);
   push32BE(header, FRMT_MAGIC);
   push32LE(header, 16);
   push16LE(header, 1);
   push16LE(header, 1);
   push32LE(header, sample_rate);
   push32LE(header, sample_rate);
   push16LE(header, 2);
   push16LE(header, 16);
   push32BE(header, DATA_MAGIC);
   push32LE(header, samples.length * 2);
   for (var i = 0; i < samples.length; ++i) {
     push16LE(header, samples[i], 2);
   }
   return header;
 }
 const Ci = Components.interfaces;
 const CC = Components.Constructor;
 const Timer = CC("@mozilla.org/timer;1", "nsITimer", "initWithCallback");
 const BinaryOutputStream = CC("@mozilla.org/binaryoutputstream;1",
                              "nsIBinaryOutputStream",
                              "setOutputStream");
 function poll(f) {
   if (f()) {
     return;
   }
   new Timer(function() { poll(f); }, 100, Ci.nsITimer.TYPE_ONE_SHOT);
 }
 function handleRequest(request, response)
 {
   var cancel = parseQuery(request, "cancelkey");
   if (cancel) {
     setState(cancel[1], "cancelled");
     response.setStatusLine(request.httpVersion, 200, "OK");
     response.write("Cancel approved!");
     return;
   }
   var samples = [];
   for (var i = 0; i < 1000000; ++i) {
     samples.push(0);
   }
   var bytes = buildWave(samples, 44100).join("");
   var key = parseQuery(request, "key");
   response.setHeader("Content-Type", "audio/x-wav");
   response.setHeader("Content-Length", ""+bytes.length, false);
   var out = new BinaryOutputStream(response.bodyOutputStream);
   var start = 0, end = bytes.length - 1;
   if (request.hasHeader("Range"))
   {
     var rangeMatch = request.getHeader("Range").match(/^bytes=(\d+)?-(\d+)?$/);
     if (rangeMatch[1] !== undefined)
       start = parseInt(rangeMatch[1], 10);
     if (rangeMatch[2] !== undefined)
       end = parseInt(rangeMatch[2], 10);
     // No start given, so the end is really the count of bytes from the
     // end of the file.
     if (start === undefined)
     {
       start = Math.max(0, bytes.length - end);
       end   = bytes.length - 1;
     }
     // start and end are inclusive
     if (end === undefined || end >= bytes.length)
       end = bytes.length - 1;
     if (end < start)
     {
       response.setStatusLine(request.httpVersion, 200, "OK");
       start = 0;
       end = bytes.length - 1;
     }
     else
     {
       response.setStatusLine(request.httpVersion, 206, "Partial Content");
       var contentRange = "bytes " + start + "-" + end + "/" + bytes.length;
       response.setHeader("Content-Range", contentRange);
     }
   }
   if (start > 0) {
     // Send all requested data
     out.write(bytes.slice(start, end + 1), end + 1 - start);
     return;
   }
   // Write the first 1.2M of the Wave file. We know the cache size is set to
   // 100K so this will fill the cache and and cause a "suspend" event on
   // the loading element.
   out.write(bytes, 1200000);
   response.processAsync();
   // Now wait for the message to cancel this response
   poll(function() {
     if (getState(key[1]) != "cancelled") {
       return false;
     }
     response.finish();
     return true;
   });
 }

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content/media/test/cancellable_request.sjs@97036ab72558 (annotated)

content/media/test/cancellable_request.sjs