mcs/class/referencesource/System.Workflow.ComponentModel/Shared/Walker.cs

   1 // Copyright (c) Microsoft Corporation. All rights reserved.
   2 //
   3 // THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
   4 // WHETHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
   5 // WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
   6 // THE ENTIRE RISK OF USE OR RESULTS IN CONNECTION WITH THE USE OF THIS CODE
   7 // AND INFORMATION REMAINS WITH THE USER.
   8
   9
  10 /*********************************************************************
  11  * NOTE: A copy of this file exists at: WF\Activities\Common
  12  * The two files must be kept in sync.  Any change made here must also
  13  * be made to WF\Activities\Common\Walker.cs
  14 *********************************************************************/
  15 namespace System.Workflow.ComponentModel
  16 {
  17     #region Imports
  18
  19     using System;
  20     using System.Collections;
  21     using System.Collections.Generic;
  22     using System.Reflection;
  23     using System.ComponentModel;
  24     using System.Diagnostics.CodeAnalysis;
  25
  26     #endregion
  27
  28     // Returns true to continue the walk, false to stop.
  29     internal delegate void WalkerEventHandler(Walker walker, WalkerEventArgs eventArgs);
  30
  31     internal enum WalkerAction
  32     {
  33         Continue = 0,
  34         Skip = 1,
  35         Abort = 2
  36     }
  37     #region Class WalkerEventArgs
  38
  39     internal sealed class WalkerEventArgs : EventArgs
  40     {
  41         private Activity currentActivity = null;
  42         private object currentPropertyOwner = null;
  43         private PropertyInfo currentProperty = null;
  44         private object currentValue = null;
  45         private WalkerAction action = WalkerAction.Continue;
  46
  47         internal WalkerEventArgs(Activity currentActivity)
  48         {
  49             this.currentActivity = currentActivity;
  50             this.currentPropertyOwner = null;
  51             this.currentProperty = null;
  52             this.currentValue = null;
  53         }
  54
  55         internal WalkerEventArgs(Activity currentActivity, object currentValue, PropertyInfo currentProperty, object currentPropertyOwner)
  56             : this(currentActivity)
  57         {
  58             this.currentPropertyOwner = currentPropertyOwner;
  59             this.currentProperty = currentProperty;
  60             this.currentValue = currentValue;
  61         }
  62
  63         public WalkerAction Action
  64         {
  65             get
  66             {
  67                 return this.action;
  68             }
  69             set
  70             {
  71                 this.action = value;
  72             }
  73         }
  74
  75         [SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
  76         public PropertyInfo CurrentProperty
  77         {
  78             get
  79             {
  80                 return this.currentProperty;
  81             }
  82         }
  83
  84         [SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
  85         public object CurrentPropertyOwner
  86         {
  87             get
  88             {
  89                 return this.currentPropertyOwner;
  90             }
  91         }
  92
  93         [SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
  94         public object CurrentValue
  95         {
  96             get
  97             {
  98                 return this.currentValue;
  99             }
 100         }
 101
 102         public Activity CurrentActivity
 103         {
 104             get
 105             {
 106                 return this.currentActivity;
 107             }
 108         }
 109     }
 110
 111     #endregion
 112
 113     internal sealed class Walker
 114     {
 115         #region Members
 116
 117         internal event WalkerEventHandler FoundActivity;
 118         internal event WalkerEventHandler FoundProperty;
 119         private bool useEnabledActivities = false;
 120
 121         #endregion
 122
 123         #region Methods
 124
 125         public Walker()
 126             : this(false)
 127         {
 128         }
 129
 130         public Walker(bool useEnabledActivities)
 131         {
 132             this.useEnabledActivities = useEnabledActivities;
 133         }
 134
 135         public void Walk(Activity seedActivity)
 136         {
 137             Walk(seedActivity, true);
 138         }
 139
 140         public void Walk(Activity seedActivity, bool walkChildren)
 141         {
 142             Queue queue = new Queue();
 143
 144             queue.Enqueue(seedActivity);
 145             while (queue.Count > 0)
 146             {
 147                 Activity activity = queue.Dequeue() as Activity;
 148
 149                 if (FoundActivity != null)
 150                 {
 151                     WalkerEventArgs args = new WalkerEventArgs(activity);
 152                     FoundActivity(this, args);
 153                     if (args.Action == WalkerAction.Abort)
 154                         return;
 155                     if (args.Action == WalkerAction.Skip)
 156                         continue;
 157                 }
 158
 159                 if (FoundProperty != null)
 160                 {
 161                     if (!WalkProperties(activity))
 162                         return;
 163                 }
 164
 165                 if (walkChildren && activity is CompositeActivity)
 166                 {
 167                     if (useEnabledActivities)
 168                     {
 169                         foreach (Activity activity2 in Design.Helpers.GetAllEnabledActivities((CompositeActivity)activity))
 170                             queue.Enqueue(activity2);
 171                     }
 172                     else
 173                     {
 174                         foreach (Activity activity2 in ((CompositeActivity)activity).Activities)
 175                             queue.Enqueue(activity2);
 176                     }
 177                 }
 178             }
 179         }
 180
 181         private bool WalkProperties(Activity seedActivity)
 182         {
 183             return WalkProperties(seedActivity as Activity, seedActivity);
 184         }
 185
 186         public bool WalkProperties(Activity activity, object obj)
 187         {
 188             Activity currentActivity = obj as Activity;
 189
 190             PropertyInfo[] props = obj.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance);
 191             foreach (PropertyInfo prop in props)
 192             {
 193                 // !!Work around: no indexer property walking
 194                 if (prop.GetIndexParameters() != null && prop.GetIndexParameters().Length > 0)
 195                     continue;
 196
 197                 DesignerSerializationVisibility visibility = GetSerializationVisibility(prop);
 198                 if (visibility == DesignerSerializationVisibility.Hidden)
 199                     continue;
 200
 201                 //Try to see if we have dynamic property associated with the object on the same object
 202                 //if so then we should compare if the dynamic property values match with the property type
 203                 //if not we bail out
 204                 object propValue = null;
 205                 DependencyProperty dependencyProperty = DependencyProperty.FromName(prop.Name, obj.GetType());
 206                 if (dependencyProperty != null && currentActivity != null)
 207                 {
 208                     if (currentActivity.IsBindingSet(dependencyProperty))
 209                         propValue = currentActivity.GetBinding(dependencyProperty);
 210                     else
 211                         propValue = currentActivity.GetValue(dependencyProperty);
 212                 }
 213                 else
 214                 {
 215                     try
 216                     {
 217                         propValue = prop.CanRead ? prop.GetValue(obj, null) : null;
 218                     }
 219                     catch
 220                     {
 221                         // Eat exceptions that occur while invoking the getter.
 222                     }
 223                 }
 224
 225                 if (FoundProperty != null)
 226                 {
 227                     WalkerEventArgs args = new WalkerEventArgs(activity, propValue, prop, obj);
 228                     FoundProperty(this, args);
 229                     if (args.Action == WalkerAction.Skip)
 230                         continue;
 231                     else if (args.Action == WalkerAction.Abort)
 232                         return false;
 233                 }
 234
 235                 if (propValue is IList)
 236                 {
 237                     //We do not need to reflect on the properties of the list
 238                     foreach (object childObj in (IList)propValue)
 239                     {
 240                         if (FoundProperty != null)
 241                         {
 242                             WalkerEventArgs args = new WalkerEventArgs(activity, childObj, null, propValue);
 243                             FoundProperty(this, args);
 244                             if (args.Action == WalkerAction.Skip)
 245                                 continue;
 246                             else if (args.Action == WalkerAction.Abort)
 247                                 return false;
 248                         }
 249                         if (childObj != null && IsBrowsableType(childObj.GetType()))
 250                         {
 251                             if (!WalkProperties(activity, childObj))
 252                                 return false;
 253                         }
 254                     }
 255                 }
 256                 else if (propValue != null && IsBrowsableType(propValue.GetType()))
 257                 {
 258                     if (!WalkProperties(activity, propValue))
 259                         return false;
 260                 }
 261             }
 262             return true;
 263         }
 264
 265         private static DesignerSerializationVisibility GetSerializationVisibility(PropertyInfo prop)
 266         {
 267             // work around!!! for Activities collection
 268             if (prop.DeclaringType == typeof(CompositeActivity) && string.Equals(prop.Name, "Activities", StringComparison.Ordinal))
 269                 return DesignerSerializationVisibility.Hidden;
 270
 271             DesignerSerializationVisibility visibility = DesignerSerializationVisibility.Visible;
 272             DesignerSerializationVisibilityAttribute[] visibilityAttrs = (DesignerSerializationVisibilityAttribute[])prop.GetCustomAttributes(typeof(DesignerSerializationVisibilityAttribute), true);
 273             if (visibilityAttrs.Length > 0)
 274                 visibility = visibilityAttrs[0].Visibility;
 275
 276             return visibility;
 277         }
 278
 279         private static bool IsBrowsableType(Type type)
 280         {
 281             bool browsable = false;
 282             BrowsableAttribute[] browsableAttrs = (BrowsableAttribute[])type.GetCustomAttributes(typeof(BrowsableAttribute), true);
 283             if (browsableAttrs.Length > 0)
 284                 browsable = browsableAttrs[0].Browsable;
 285             return browsable;
 286         }
 287         #endregion
 288     }
 289 }