chrome/browser/resources/net_internals/log_grouper.js

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 /**
   6  * @fileoverview
   7  * LogGroupEntry is a wrapper around log entries, which makes it easier to
   8  * find the corresponding start/end of events.
   9  *
  10  * This is used internally by the log and timeline views to pretty print
  11  * collections of log entries.
  12  */
  13
  14 // TODO(eroman): document these methods!
  15
  16 var LogGroupEntry = (function() {
  17   'use strict';
  18
  19   function LogGroupEntry(origEntry, index) {
  20     this.orig = origEntry;
  21     this.index = index;
  22   }
  23
  24   LogGroupEntry.prototype = {
  25     isBegin: function() {
  26       return this.orig.phase == EventPhase.PHASE_BEGIN;
  27     },
  28
  29     isEnd: function() {
  30       return this.orig.phase == EventPhase.PHASE_END;
  31     },
  32
  33     getDepth: function() {
  34       var depth = 0;
  35       var p = this.parentEntry;
  36       while (p) {
  37         depth += 1;
  38         p = p.parentEntry;
  39       }
  40       return depth;
  41     }
  42   };
  43
  44   function findParentIndex(parentStack, eventType) {
  45     for (var i = parentStack.length - 1; i >= 0; --i) {
  46       if (parentStack[i].orig.type == eventType)
  47         return i;
  48     }
  49     return -1;
  50   }
  51
  52   /**
  53    * Returns a list of LogGroupEntrys. This basically wraps the original log
  54    * entry, but makes it easier to find the start/end of the event.
  55    */
  56   LogGroupEntry.createArrayFrom = function(origEntries) {
  57     var groupedEntries = [];
  58
  59     // Stack of enclosing PHASE_BEGIN elements.
  60     var parentStack = [];
  61
  62     for (var i = 0; i < origEntries.length; ++i) {
  63       var origEntry = origEntries[i];
  64
  65       var groupEntry = new LogGroupEntry(origEntry, i);
  66       groupedEntries.push(groupEntry);
  67
  68       // If this is the end of an event, match it to the start.
  69       if (groupEntry.isEnd()) {
  70         // Walk up the parent stack to find the corresponding BEGIN for this
  71         // END.
  72         var parentIndex =
  73             findParentIndex(parentStack, groupEntry.orig.type);
  74
  75         if (parentIndex == -1) {
  76           // Unmatched end.
  77         } else {
  78           groupEntry.begin = parentStack[parentIndex];
  79
  80           // Consider this as the terminator for all open BEGINs up until
  81           // parentIndex.
  82           while (parentIndex < parentStack.length) {
  83             var p = parentStack.pop();
  84             p.end = groupEntry;
  85           }
  86         }
  87       }
  88
  89       // Inherit the current parent.
  90       if (parentStack.length > 0)
  91         groupEntry.parentEntry = parentStack[parentStack.length - 1];
  92
  93       if (groupEntry.isBegin())
  94         parentStack.push(groupEntry);
  95     }
  96
  97     return groupedEntries;
  98   };
  99
 100   return LogGroupEntry;
 101 })();