tracing/model/slice.html

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Copyright (c) 2013 The Chromium Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
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<link rel="import" href="/tracing/base/units/time_stamp.html">
<link rel="import" href="/tracing/model/timed_event.html">

<script>
'use strict';

/**
 * @fileoverview Provides the Slice class.
 */
tr.exportTo('tr.model', function() {
  /**
   * A Slice represents an interval of time plus parameters associated
   * with that interval.
   *
   * @constructor
   */
  function Slice(category, title, colorId, start, args, opt_duration,
                 opt_cpuStart, opt_cpuDuration, opt_argsStripped,
                 opt_bind_id) {
    tr.model.TimedEvent.call(this, start);

    this.category = category || '';
    this.title = title;
    this.colorId = colorId;
    this.args = args;
    this.startStackFrame = undefined;
    this.endStackFrame = undefined;
    this.didNotFinish = false;
    this.inFlowEvents = [];
    this.outFlowEvents = [];
    this.subSlices = [];
    this.selfTime = undefined;
    this.cpuSelfTime = undefined;
    this.important = false;
    this.parentContainer = undefined;
    this.argsStripped = false;

    this.bind_id_ = opt_bind_id;

    // parentSlice and isTopLevel will be set by SliceGroup.
    this.parentSlice = undefined;
    this.isTopLevel = false;
    // After SliceGroup processes Slices, isTopLevel should be equivalent to
    // !parentSlice.

    if (opt_duration !== undefined)
      this.duration = opt_duration;

    if (opt_cpuStart !== undefined)
      this.cpuStart = opt_cpuStart;

    if (opt_cpuDuration !== undefined)
      this.cpuDuration = opt_cpuDuration;

    if (opt_argsStripped !== undefined)
      this.argsStripped = true;
  }

  Slice.prototype = {
    __proto__: tr.model.TimedEvent.prototype,


    get analysisTypeName() {
      return this.title;
    },

    get userFriendlyName() {
      return 'Slice ' + this.title + ' at ' +
          tr.b.units.TimeStamp.format(this.start);
    },

    findDescendentSlice: function(targetTitle) {
      if (!this.subSlices)
        return undefined;

      for (var i = 0; i < this.subSlices.length; i++) {
        if (this.subSlices[i].title == targetTitle)
          return this.subSlices[i];
        var slice = this.subSlices[i].findDescendentSlice(targetTitle);
        if (slice) return slice;
      }
      return undefined;
    },

    get mostTopLevelSlice() {
      var curSlice = this;
      while (curSlice.parentSlice)
        curSlice = curSlice.parentSlice;

      return curSlice;
    },

    /**
     * Obtains all subsequent slices of this slice.
     *
     * Subsequent slices are slices that get executed after a particular
     * slice, i.e., all the functions that are called after the current one.
     *
     * For instance, E.iterateAllSubsequentSlices() in the following example:
     * [     A          ]
     * [ B][  D   ][ G  ]
     *  [C] [E][F]  [H]
     * will pass F, G, then H to the provided callback.
     *
     * The reason we need subsequent slices of a particular slice is that
     * when there is flow event goes into, e.g., E, we only want to highlight
     * E's subsequent slices to indicate the execution order.
     *
     * The idea to calculate the subsequent slices of slice E is to view
     * the slice group as a tree where the top-level slice A is the root node.
     * The preorder depth-first-search (DFS) order is naturally equivalent
     * to the function call order. We just need to perform a DFS, and start
     * recording the slices after we see the occurance of E.
     */
    iterateAllSubsequentSlices: function(callback, opt_this) {
      var parentStack = [];
      var started = false;

      // get the root node and push it to the DFS stack
      var topmostSlice = this.mostTopLevelSlice;
      parentStack.push(topmostSlice);

      // Using the stack to perform DFS
      while (parentStack.length !== 0) {
        var curSlice = parentStack.pop();

        if (started)
          callback.call(opt_this, curSlice);
        else
          started = (curSlice.guid === this.guid);

        for (var i = curSlice.subSlices.length - 1; i >= 0; i--) {
          parentStack.push(curSlice.subSlices[i]);
        }
      }
    },

    get subsequentSlices() {
      var res = [];

      this.iterateAllSubsequentSlices(function(subseqSlice) {
        res.push(subseqSlice);
      });

      return res;
    },

    /**
     * Obtains the parents of a slice, from the most immediate to the root.
     *
     * For instance, E.iterateAllAncestors() in the following example:
     * [     A          ]
     * [ B][  D   ][ G  ]
     *  [C] [E][F]  [H]
     * will pass D, then A to the provided callback, in the order from the
     * leaves to the root.
     */
    iterateAllAncestors: function(callback, opt_this) {
      var curSlice = this;

      while (curSlice.parentSlice) {
        curSlice = curSlice.parentSlice;
        callback.call(opt_this, curSlice);
      }
    },

    get ancestorSlices() {
      var res = [];

      this.iterateAllAncestors(function(ancestor) {
        res.push(ancestor);
      });

      return res;
    },

    iterateEntireHierarchy: function(callback, opt_this) {
      var mostTopLevelSlice = this.mostTopLevelSlice;
      callback.call(opt_this, mostTopLevelSlice);
      mostTopLevelSlice.iterateAllSubsequentSlices(callback, opt_this);
    },

    get entireHierarchy() {
      var res = [];

      this.iterateEntireHierarchy(function(slice) {
        res.push(slice);
      });

      return res;
    },

    /**
     * Returns this slice, and its ancestor and subsequent slices.
     *
     * For instance, E.ancestorAndSubsequentSlices in the following example:
     * [     A          ]
     * [ B][  D   ][ G  ]
     *  [C] [E][F]  [H]
     * will return E, D, A, F, G, and H, where E is itself, D and A are
     * E's ancestors, and F, G, and H are subsequent slices of E
     */
    get ancestorAndSubsequentSlices() {
      var res = [];

      res.push(this);

      this.iterateAllAncestors(function(aSlice) {
        res.push(aSlice);
      });

      this.iterateAllSubsequentSlices(function(sSlice) {
        res.push(sSlice);
      });

      return res;
    },

    iterateAllDescendents: function(callback, opt_this) {
      this.subSlices.forEach(callback, opt_this);
      this.subSlices.forEach(function(subSlice) {
        subSlice.iterateAllDescendents(callback, opt_this);
      }, opt_this);
    },

    get descendentSlices() {
      var res = [];

      this.iterateAllDescendents(function(des) {
        res.push(des);
      });

      return res;
    }

  };

  return {
    Slice: Slice
  };
});
</script>