Add unit tests for about:tracing TimelineModel.

chrome/browser/resources/tracing/timeline_model.js

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 
 /**
  * @fileoverview TimelineModel is a parsed representation of the
  * TraceEvents obtained from base/trace_event in which the begin-end
  * tokens are converted into a hierarchy of processes, threads,
  * subrows, and slices.
@@ skipping 102 matching lines @@
         this.maxTimestamp = undefined;
       }
     }
 
   };
 
   /**
    * Comparison between threads that orders first by pid,
    * then by names, then by tid.
    */
-  TimelineThread.compare = function(x,y) {
-    if(x.parent.pid != y.parent.pid) {
+  TimelineThread.compare = function(x, y) {
+    if (x.parent.pid != y.parent.pid) {
       return x.parent.pid - y.parent.pid;
     }
 
     if (x.name && y.name) {
       var tmp = x.name.localeCompare(y.name);
       if (tmp == 0)
         return x.tid - y.tid;
       return tmp;
     } else if (x.name) {
       return -1;
-    } else if (y.name){
+    } else if (y.name) {
       return 1;
     } else {
       return x.tid - y.tid;
     }
   };
 
 
   /**
    * The TimelineProcess represents a single process in the
    * trace. Right now, we keep this around purely for bookkeeping
    * reasons.
    * @constructor
    */
   function TimelineProcess(pid) {
     this.pid = pid;
     this.threads = {};
   };
 
   TimelineProcess.prototype = {
-    getThread: function(tid) {
+    get numThreads() {
+      var n = 0;
+      for (var p in this.threads)

[arv (Not doing code reviews), 2011/10/21 17:09:18]

Missing {}

[nduca, 2011/10/21 19:50:40]

Done.

+        n++;
+      return n;
+    },
+
+    getOrCreateThread: function(tid) {
       if (!this.threads[tid])
         this.threads[tid] = new TimelineThread(this, tid);
       return this.threads[tid];
     }
   };
 
   /**
+   * Computes a simplistic hashcode of the provide name. Used to chose colors
+   * for slices.
+   * @param {string} name The string to hash.
+   */
+  function getStringHash(name) {

[arv (Not doing code reviews), 2011/10/21 17:09:18]

This looks like it might be overkill for choosing colors.

[nduca, 2011/10/21 19:50:40]

Do you have any suggestions? The goal is to get a hash for a string that is
fairly random but also stable across computers --- this way "that red task"
shows up as red on your and my computer. Tracing has been using this one for a
few months and it seems good-ish.

[arv (Not doing code reviews), 2011/10/21 23:43:53]

I don't have any better idea. Are the strings short? If not maybe limit the
number of chars you go through.

+    var hash = 0;
+    for (var i = 0; i < name.length; ++i)
+      hash = (hash + 37 * hash + 11 * name.charCodeAt(i)) % 0xFFFFFFFF;
+    return hash;
+  }
+
+  /**
    * Builds a model from an array of TraceEvent objects.
    * @param {Array} events An array of TraceEvents created by
    *     TraceEvent.ToJSON().
    * @constructor
    */
   function TimelineModel(events) {
     this.processes = {};
     this.importErrors = [];
 
     if (events)
       this.importEvents(events);
   }
 
   TimelineModel.prototype = {
     __proto__: cr.EventTarget.prototype,
 
-    getProcess: function(pid) {
+    get numProcesses() {
+      var n = 0;
+      for (var p in this.processes)
+        n++;
+      return n;
+    },
+
+    getOrCreateProcess: function(pid) {
       if (!this.processes[pid])
         this.processes[pid] = new TimelineProcess(pid);
       return this.processes[pid];
     },
 
     /**
      * The import takes an array of json-ified TraceEvents and adds them into
      * the TimelineModel as processes, threads, and slices.
      */
     importEvents: function(events) {
       // A ptid is a pid and tid joined together x:y fashion, eg 1024:130
       // The ptid is a unique key for a thread in the trace.
       this.importErrors = [];
 
       // Threadstate
       const numColorIds = 30;
       function ThreadState(tid) {
         this.openSlices = [];
         this.openNonNestedSlices = {};
       }
       var threadStateByPTID = {};
 
       var nameToColorMap = {};
       function getColor(name) {
         if (!(name in nameToColorMap)) {
-          // Compute a simplistic hashcode of the string so we get consistent
-          // coloring across traces.
-          var hash = 0;
-          for (var i = 0; i < name.length; ++i)
-            hash = (hash + 37 * hash + 11 * name.charCodeAt(i)) % 0xFFFFFFFF;
+          var hash = getStringHash(name);
           nameToColorMap[name] = hash % numColorIds;
         }
         return nameToColorMap[name];
       }
 
       var self = this;
 
       /**
        * Helper to process a 'begin' event (e.g. initiate a slice).
        * @param {ThreadState} state Thread state (holds slices).
@@ skipping 26 matching lines @@
         if (event.args['ui-nest'] === '0') {
           var sliceID = event.name;
           for (var x in event.args)
             sliceID += ';' + event.args[x];
           var slice = state.openNonNestedSlices[sliceID];
           if (!slice)
             return;
           slice.slice.duration = event.ts - slice.slice.start;
 
           // Store the slice in a non-nested subrow.
-          var thread = self.getProcess(event.pid).getThread(event.tid);
+          var thread = self.getOrCreateProcess(event.pid)
+                           .getOrCreateThread(event.tid);

[arv (Not doing code reviews), 2011/10/21 17:09:18]

binop before newline

[nduca, 2011/10/21 19:50:40]

Done.

           thread.addNonNestedSlice(slice.slice);
           delete state.openNonNestedSlices[name];
         } else {
           if (state.openSlices.length == 0) {
             // Ignore E events that are unmatched.
             return;
           }
           var slice = state.openSlices.pop().slice;
           slice.duration = event.ts - slice.start;
 
           // Store the slice on the correct subrow.
-          var thread = self.getProcess(event.pid).getThread(event.tid);
+          var thread = self.getOrCreateProcess(event.pid)
+                           .getOrCreateThread(event.tid);
           var subRowIndex = state.openSlices.length;
           thread.getSubrow(subRowIndex).push(slice);
 
           // Add the slice to the subSlices array of its parent.
           if (state.openSlices.length) {
             var parentSlice = state.openSlices[state.openSlices.length - 1];
             parentSlice.slice.subSlices.push(slice);
           }
         }
       }
@@ skipping 11 matching lines @@
           processBegin(state, event);
         } else if (event.ph == 'E') {
           processEnd(state, event);
         } else if (event.ph == 'I') {
           // Treat an Instant event as a duration 0 slice.
           // TimelineSliceTrack's redraw() knows how to handle this.
           processBegin(state, event);
           processEnd(state, event);
         } else if (event.ph == 'M') {
           if (event.name == 'thread_name') {
-            var thread = this.getProcess(event.pid).getThread(event.tid);
+            var thread = this.getOrCreateProcess(event.pid)
+                             .getOrCreateThread(event.tid);
             thread.name = event.args.name;
           } else {
             this.importErrors.push('Unrecognized metadata name: ' + event.name);
           }
         } else {
           this.importErrors.push('Unrecognized event phase: ' + event.ph +
-                          '(' + event.name + ')');
+                                 '(' + event.name + ')');
         }
       }
       this.pruneEmptyThreads();
       this.updateBounds();
 
       // Add end events for any events that are still on the stack. These
       // are events that were still open when trace was ended, and can often
       // indicate deadlock behavior.
       for (var ptid in threadStateByPTID) {
         var state = threadStateByPTID[ptid];
         while (state.openSlices.length > 0) {
           var slice = state.openSlices.pop();
           slice.slice.duration = this.maxTimestamp - slice.slice.start;
           slice.slice.didNotFinish = true;
           var event = events[slice.index];
 
           // Store the slice on the correct subrow.
-          var thread = this.getProcess(event.pid).getThread(event.tid);
+          var thread = this.getOrCreateProcess(event.pid)
+                           .getOrCreateThread(event.tid);
           var subRowIndex = state.openSlices.length;
           thread.getSubrow(subRowIndex).push(slice.slice);
 
           // Add the slice to the subSlices array of its parent.
           if (state.openSlices.length) {
             var parentSlice = state.openSlices[state.openSlices.length - 1];
             parentSlice.slice.subSlices.push(slice.slice);
           }
         }
       }
 
       this.shiftWorldToMicroseconds();
 
       var boost = (this.maxTimestamp - this.minTimestamp) * 0.15;
       this.minTimestamp = this.minTimestamp - boost;
       this.maxTimestamp = this.maxTimestamp + boost;
     },
 
     /**
      * Removes threads from the model that have no subrows.
      */
     pruneEmptyThreads: function() {
       for (var pid in this.processes) {
         var process = this.processes[pid];
-        var prunedThreads = [];
+        var prunedThreads = {};
         for (var tid in process.threads) {
           var thread = process.threads[tid];
           if (thread.subRows[0].length || thread.nonNestedSubRows.legnth)
-            prunedThreads.push(thread);
+            prunedThreads[tid] = thread;
         }
         process.threads = prunedThreads;
       }
     },
 
     updateBounds: function() {
       var wmin = Infinity;
       var wmax = -wmin;
       var threads = this.getAllThreads();
       for (var tI = 0; tI < threads.length; tI++) {
@@ skipping 39 matching lines @@
         for (var tid in process.threads) {
           threads.push(process.threads[tid]);
         }
       }
       return threads;
     }
 
   };
 
   return {
+    getStringHash: getStringHash,
     TimelineSlice: TimelineSlice,
     TimelineThread: TimelineThread,
     TimelineProcess: TimelineProcess,
     TimelineModel: TimelineModel
   };
 });