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      1 // Copyright (c) 2013 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 'use strict';
      6 
      7 base.require('base.settings');
      8 
      9 base.exportTo('tracing', function() {
     10   var Settings = base.Settings;
     11 
     12   /**
     13    * A way to persist settings specific to parts of a trace model.
     14    *
     15    * This object should not be persisted because it builds up internal data
     16    * structures that map model objects to settings keys. It should thus be
     17    * created for the druation of whatever interaction(s) you're going to do with
     18    * model settings, and then discarded.
     19    *
     20    * This system works on a notion of an object key: for an object's key, it
     21    * considers all the other keys in the model. If it is unique, then the key is
     22    * persisted to base.Settings. However, if it is not unique, then the
     23    * setting is stored on the object itself. Thus, objects with unique keys will
     24    * be persisted across page reloads, whereas objects with nonunique keys will
     25    * not.
     26    */
     27   function TraceModelSettings(model) {
     28     this.model = model;
     29     this.objectsByKey_ = [];
     30     this.nonuniqueKeys_ = [];
     31     this.buildObjectsByKeyMap_();
     32     this.removeNonuniqueKeysFromSettings_();
     33   }
     34 
     35   TraceModelSettings.prototype = {
     36     buildObjectsByKeyMap_: function() {
     37       var objects = [this.model.kernel];
     38       objects.push.apply(objects,
     39                          base.dictionaryValues(this.model.processes));
     40       objects.push.apply(objects,
     41                          this.model.getAllThreads());
     42       var objectsByKey = {};
     43       var NONUNIQUE_KEY = 'nonuniqueKey';
     44       for (var i = 0; i < objects.length; i++) {
     45         var object = objects[i];
     46         var objectKey = object.getSettingsKey();
     47         if (!objectKey)
     48           continue;
     49         if (objectsByKey[objectKey] === undefined) {
     50           objectsByKey[objectKey] = object;
     51           continue;
     52         }
     53         objectsByKey[objectKey] = NONUNIQUE_KEY;
     54       }
     55 
     56       var nonuniqueKeys = {};
     57       base.dictionaryKeys(objectsByKey).forEach(function(objectKey) {
     58         if (objectsByKey[objectKey] !== NONUNIQUE_KEY)
     59           return;
     60         delete objectsByKey[objectKey];
     61         nonuniqueKeys[objectKey] = true;
     62       });
     63 
     64       this.nonuniqueKeys = nonuniqueKeys;
     65       this.objectsByKey_ = objectsByKey;
     66     },
     67 
     68     removeNonuniqueKeysFromSettings_: function() {
     69       var settings = Settings.get('trace_model_settings', {});
     70       var settingsChanged = false;
     71       base.dictionaryKeys(settings).forEach(function(objectKey) {
     72         if (!this.nonuniqueKeys[objectKey])
     73           return;
     74         settingsChanged = true;
     75         delete settings[objectKey];
     76       }, this);
     77       if (settingsChanged)
     78         Settings.set('trace_model_settings', settings);
     79     },
     80 
     81     hasUniqueSettingKey: function(object) {
     82       var objectKey = object.getSettingsKey();
     83       if (!objectKey)
     84         return false;
     85       return this.objectsByKey_[objectKey] !== undefined;
     86     },
     87 
     88     getSettingFor: function(object, objectLevelKey, defaultValue) {
     89       var objectKey = object.getSettingsKey();
     90       if (!objectKey || !this.objectsByKey_[objectKey]) {
     91         var ephemeralValue = object.ephemeralSettings[objectLevelKey];
     92         if (ephemeralValue !== undefined)
     93           return ephemeralValue;
     94         return defaultValue;
     95       }
     96 
     97       var settings = Settings.get('trace_model_settings', {});
     98       if (!settings[objectKey])
     99         settings[objectKey] = {};
    100       var value = settings[objectKey][objectLevelKey];
    101       if (value !== undefined)
    102         return value;
    103       return defaultValue;
    104     },
    105 
    106     setSettingFor: function(object, objectLevelKey, value) {
    107       var objectKey = object.getSettingsKey();
    108       if (!objectKey || !this.objectsByKey_[objectKey]) {
    109         object.ephemeralSettings[objectLevelKey] = value;
    110         return;
    111       }
    112 
    113       var settings = Settings.get('trace_model_settings', {});
    114       if (!settings[objectKey])
    115         settings[objectKey] = {};
    116       settings[objectKey][objectLevelKey] = value;
    117       Settings.set('trace_model_settings', settings);
    118     }
    119   };
    120 
    121   return {
    122     TraceModelSettings: TraceModelSettings
    123   };
    124 });
    125