Extract relevant (partial backtrace) information from heap-dump using OQL

heap-dump.backtrace.js

map( heap.objects('org.jruby.runtime.ThreadContext'), function(ctx) {
   var str = toHtml(ctx) + " oid: " + objectid(ctx);
   str += "  ";
   var toHtmlObj = function(obj) { return "<br>  " + toHtml(obj); };
   try {
   //return str + doObjPath(ctx, toHtmlObj, 'thread', 'threadImpl', 'nativeThread', 'referent');

   str += resolveObjPath(ctx, 'thread', 'threadImpl', 'nativeThread', 'referent', 'name').toString();
   str += '<br> backtraceIndex = ' + ctx.backtraceIndex;   

   var i = 0;
   map( resolve(ctx, 'backtrace'), function(e) { 
      map( [ heap.findObject( objectid(e) ) ], function(elem) {
        if (elem) str += "<br> " + (i++) + ' ' + showBacktraceElement(elem);
      } ); 
   } );
   return str;

   return str;
   } catch(e) { return str + " ERROR: " + e; }
});

function doObjPath(obj, fn) { // some, fn, 'foo', 'bar'
   if (typeof(fn) === 'undefined') throw 'no function given';
   
   var out = ''; var args = Array.prototype.slice.call(arguments);

   if ( args.length > 2 ) {
      var prop = args[2]; var args0 = args[0];
      for ( var i=2; i<args.length - 1; i++ ) { args[i] = args[i+1]; }
      args = args.slice(0, args.length - 1);
      map( [ heap.findObject( objectid( obj[prop] ) ) ], function(elem) { 
         args[0] = elem; out += fn(elem) + ' (' + prop + ')'; 
      } );

      //out += ' - ' + args.toString();

      if ( args0 === args[0] ) out += "'" + prop + "' not set!";
      else out += doObjPath.apply(this, args);
   }
   return out;
}

function resolveObjPath(obj) { // this, 'foo', 'bar' -> this['foo']['bar']
   var last;
   var args = Array.prototype.slice.call(arguments);
   args.unshift(obj); // args[0]
   args[1] = function(val) { last = val; };
   doObjPath.apply(this, args);
   return last;
}

function resolve(obj, prop) {
   var val;
   map( [ heap.findObject( objectid( obj[prop] ) ) ], function(elem) { 
      val = elem; 
   } );
   return val;
}

function formatBacktraceElement(elem) {
    if ( ! elem.method ) return null; var str = '';
    str += heap.findObject( objectid(elem.method) ).toString();
    str += ' at ';
    str += elem.filename ? heap.findObject( objectid(elem.filename) ).toString() : null;
    str += ':' + elem.line;
    return str;
}