code: function(dir, update) {
  		var self = this,
  			prev = update? dir : (self.file(dir.hash) || dir),
  			prevTs = prev.ts,
  			change = false;
  		// backup original stats
  		if (update || !dir._realStats) {
  			dir._realStats = {
  				locked: dir.locked || 0,
  				dirs: dir.dirs || 0,
  				ts: dir.ts
  			};
  		}
  		// set lock
  		dir.locked = 1;
  		if (!prev.locked) {
  			change = true;
  		}
  		// has leaf root to `dirs: 1`
  		dir.dirs = 1;
  		if (!prev.dirs) {
  			change = true;
  		}
  		// set ts
  		$.each(self.leafRoots[dir.hash], function() {
  			var f = self.file(this);
  			if (f && f.ts && (dir.ts || 0) < f.ts) {
  				dir.ts = f.ts;
  			}
  		});
  		if (prevTs !== dir.ts) {
  			change = true;
  		}
  
  		return change;
  	}
docs: Apply leaf root stats to target directory
  
  @param      object     dir     object of target directory
  @param      boolean    update  is force update
  
  @return     boolean    dir object was chenged