mcs/class/System/System.ComponentModel/BackgroundWorker.cs

   1 //
   2 // BackgroundWorker.cs
   3 //
   4 // Authors:
   5 //      Atsushi Enomoto <atsushi@ximian.com>
   6 //
   7 // Copyright (C) 2006 Novell, Inc.
   8 //
   9
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30 #if NET_2_0
  31 using System.Collections.Generic;
  32 using System.Threading;
  33
  34 namespace System.ComponentModel
  35 {
  36         public class BackgroundWorker : Component
  37         {
  38                 public BackgroundWorker ()
  39                 {
  40                 }
  41
  42                 AsyncOperation async;
  43                 bool cancel_pending, report_progress = false, support_cancel = false;
  44
  45                 Dictionary<object,AsyncOperation> operations =
  46                         new Dictionary<object,AsyncOperation> ();
  47
  48                 public event DoWorkEventHandler DoWork;
  49                 public event ProgressChangedEventHandler ProgressChanged;
  50                 public event RunWorkerCompletedEventHandler RunWorkerCompleted;
  51
  52                 [Browsable (false)]
  53                 public bool CancellationPending {
  54                         get { return cancel_pending; }
  55                 }
  56
  57                 [Browsable (false)]
  58                 public bool IsBusy {
  59                         get { return async != null; }
  60                 }
  61
  62                 [DefaultValue (false)]
  63                 public bool WorkerReportsProgress {
  64                         get { return report_progress; }
  65                         set { report_progress = value; }
  66                 }
  67
  68                 [DefaultValue (false)]
  69                 public bool WorkerSupportsCancellation {
  70                         get { return support_cancel; }
  71                         set { support_cancel = value; }
  72                 }
  73
  74                 [MonoTODO ("What should happen when IsBusy != true?")]
  75                 public void CancelAsync ()
  76                 {
  77                         if (!support_cancel)
  78                                 throw new InvalidOperationException ("This background worker does not support cancellation.");
  79
  80                         // FIXME: verify the expected behavior
  81                         if (!IsBusy)
  82                                 return;
  83
  84                         cancel_pending = true;
  85
  86                         async.PostOperationCompleted (delegate (object darg) {
  87                                 OnRunWorkerCompleted (
  88                                         new RunWorkerCompletedEventArgs (
  89                                         null, null, true));
  90                                 this.async = null;
  91                                 cancel_pending = false;
  92                                 },
  93                                 null);
  94                 }
  95
  96                 public void ReportProgress (int percentProgress)
  97                 {
  98                         ReportProgress (percentProgress, null);
  99                 }
 100
 101                 [MonoTODO ("What should happen when IsBusy != true?")]
 102                 public void ReportProgress (int percentProgress, object userState)
 103                 {
 104                         if (!WorkerReportsProgress)
 105                                 throw new InvalidOperationException ("This background worker does not report progress.");
 106
 107                         // FIXME: verify the expected behavior
 108                         if (!IsBusy)
 109                                 return;
 110
 111                         async.Post (delegate (object o) {
 112                                 ProgressChangedEventArgs e = o as ProgressChangedEventArgs;
 113                                 OnProgressChanged (e);
 114                                 },
 115                                 new ProgressChangedEventArgs (percentProgress, userState));
 116                 }
 117
 118                 public void RunWorkerAsync ()
 119                 {
 120                         RunWorkerAsync (null);
 121                 }
 122
 123                 delegate void ProcessWorkerEventHandler (object argument, AsyncOperation async, SendOrPostCallback callback);
 124
 125                 void ProcessWorker (object argument, AsyncOperation async, SendOrPostCallback callback)
 126                 {
 127                         // do worker
 128                         Exception error = null;
 129                         DoWorkEventArgs e = new DoWorkEventArgs (argument);
 130                         try {
 131                                 OnDoWork (e);
 132                         } catch (Exception ex) {
 133                                 error = ex;
 134                         }
 135                         callback (new object [] {
 136                                 new RunWorkerCompletedEventArgs (
 137                                         e.Result, error, e.Cancel),
 138                                 async});
 139                 }
 140
 141                 void CompleteWorker (object state)
 142                 {
 143                         object [] args = (object []) state;
 144                         RunWorkerCompletedEventArgs e =
 145                                 args [0] as RunWorkerCompletedEventArgs;
 146                         AsyncOperation async = args [1] as AsyncOperation;
 147
 148                         SendOrPostCallback callback = delegate (object darg) {
 149                                 OnRunWorkerCompleted (darg as RunWorkerCompletedEventArgs);
 150                         };
 151
 152                         async.PostOperationCompleted (callback, e);
 153
 154                         this.async = null;
 155                 }
 156
 157                 public void RunWorkerAsync (object argument)
 158                 {
 159                         if (IsBusy)
 160                                 throw new InvalidOperationException ("The background worker is busy.");
 161
 162                         async = AsyncOperationManager.CreateOperation (this);
 163
 164                         ProcessWorkerEventHandler handler =
 165                                 new ProcessWorkerEventHandler (ProcessWorker);
 166                         handler.BeginInvoke (argument, async, CompleteWorker, null, null);
 167                 }
 168
 169                 protected virtual void OnDoWork (DoWorkEventArgs e)
 170                 {
 171                         if (DoWork != null)
 172                                 DoWork (this, e);
 173                 }
 174
 175                 protected virtual void OnProgressChanged (ProgressChangedEventArgs e)
 176                 {
 177                         if (ProgressChanged != null)
 178                                 ProgressChanged (this, e);
 179                 }
 180
 181                 protected virtual void OnRunWorkerCompleted (RunWorkerCompletedEventArgs e)
 182                 {
 183                         if (RunWorkerCompleted != null)
 184                                 RunWorkerCompleted (this, e);
 185                 }
 186         }
 187 }
 188 #endif