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      1 // Copyright (c) 2010 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  * LogGroupEntry is a wrapper around log entries, which makes it easier to
      7  * find the corresponding start/end of events.
      8  *
      9  * This is used internally by the log and timeline views to pretty print
     10  * collections of log entries.
     11  *
     12  * @fileoverview
     13  */
     14 
     15 // TODO(eroman): document these methods!
     16 
     17 function LogGroupEntry(origEntry, index) {
     18   this.orig = origEntry;
     19   this.index = index;
     20 }
     21 
     22 LogGroupEntry.prototype.isBegin = function() {
     23   return this.orig.phase == LogEventPhase.PHASE_BEGIN;
     24 };
     25 
     26 LogGroupEntry.prototype.isEnd = function() {
     27   return this.orig.phase == LogEventPhase.PHASE_END
     28 };
     29 
     30 LogGroupEntry.prototype.getDepth = function() {
     31   var depth = 0;
     32   var p = this.parentEntry;
     33   while (p) {
     34     depth += 1;
     35     p = p.parentEntry;
     36   }
     37   return depth;
     38 };
     39 
     40 function findParentIndex(parentStack, eventType) {
     41   for (var i = parentStack.length - 1; i >= 0; --i) {
     42     if (parentStack[i].orig.type == eventType)
     43       return i;
     44   }
     45   return -1;
     46 }
     47 
     48 /**
     49  * Returns a list of LogGroupEntrys. This basically wraps the original log
     50  * entry, but makes it easier to find the start/end of the event.
     51  */
     52 LogGroupEntry.createArrayFrom = function(origEntries) {
     53   var groupedEntries = [];
     54 
     55   // Stack of enclosing PHASE_BEGIN elements.
     56   var parentStack = [];
     57 
     58   for (var i = 0; i < origEntries.length; ++i) {
     59     var origEntry = origEntries[i];
     60 
     61     var groupEntry = new LogGroupEntry(origEntry, i);
     62     groupedEntries.push(groupEntry);
     63 
     64     // If this is the end of an event, match it to the start.
     65     if (groupEntry.isEnd()) {
     66       // Walk up the parent stack to find the corresponding BEGIN for this END.
     67       var parentIndex =
     68           findParentIndex(parentStack, groupEntry.orig.type);
     69 
     70       if (parentIndex == -1) {
     71         // Unmatched end.
     72       } else {
     73         groupEntry.begin = parentStack[parentIndex];
     74 
     75         // Consider this as the terminator for all open BEGINs up until
     76         // parentIndex.
     77         while (parentIndex < parentStack.length) {
     78           var p = parentStack.pop();
     79           p.end = groupEntry;
     80         }
     81       }
     82     }
     83 
     84     // Inherit the current parent.
     85     if (parentStack.length > 0)
     86       groupEntry.parentEntry = parentStack[parentStack.length - 1];
     87 
     88     if (groupEntry.isBegin())
     89       parentStack.push(groupEntry);
     90   }
     91 
     92   return groupedEntries;
     93 }
     94