Mercurial > pub > ImplabNet
annotate Implab/AbstractPromise.cs @ 130:671f60cd0250 v2
fixed Resove method bug when calling it on already cancelled promise
| author | cin |
|---|---|
| date | Fri, 30 Jan 2015 17:07:17 +0300 |
| parents | f803565868a4 |
| children | f75cfa58e3d4 |
| rev | line source |
|---|---|
| 119 | 1 using System; |
| 2 using Implab.Parallels; | |
| 3 using System.Threading; | |
| 4 using System.Reflection; | |
| 5 | |
| 6 namespace Implab { | |
| 7 public abstract class AbstractPromise<THandler> { | |
| 8 | |
| 9 const int UNRESOLVED_SATE = 0; | |
| 10 const int TRANSITIONAL_STATE = 1; | |
| 11 const int SUCCEEDED_STATE = 2; | |
| 12 const int REJECTED_STATE = 3; | |
| 13 const int CANCELLED_STATE = 4; | |
| 14 | |
| 125 | 15 const int RESERVED_HANDLERS_COUNT = 4; |
| 16 | |
| 119 | 17 int m_state; |
| 18 Exception m_error; | |
| 125 | 19 int m_handlersCount; |
| 119 | 20 |
| 125 | 21 readonly THandler[] m_handlers = new THandler[RESERVED_HANDLERS_COUNT]; |
| 22 MTQueue<THandler> m_extraHandlers; | |
| 23 int m_handlerPointer = -1; | |
| 24 int m_handlersCommited; | |
| 119 | 25 |
| 26 #region state managment | |
| 27 bool BeginTransit() { | |
| 28 return UNRESOLVED_SATE == Interlocked.CompareExchange(ref m_state, TRANSITIONAL_STATE, UNRESOLVED_SATE); | |
| 29 } | |
| 30 | |
| 31 void CompleteTransit(int state) { | |
| 32 if (TRANSITIONAL_STATE != Interlocked.CompareExchange(ref m_state, state, TRANSITIONAL_STATE)) | |
| 33 throw new InvalidOperationException("Can't complete transition when the object isn't in the transitional state"); | |
| 34 } | |
| 35 | |
| 36 void WaitTransition() { | |
| 37 while (m_state == TRANSITIONAL_STATE) { | |
| 38 Thread.MemoryBarrier(); | |
| 39 } | |
| 40 } | |
| 41 | |
|
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671f60cd0250
fixed Resove method bug when calling it on already cancelled promise
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42 protected bool BeginSetResult() { |
| 119 | 43 if (!BeginTransit()) { |
| 44 WaitTransition(); | |
| 45 if (m_state != CANCELLED_STATE) | |
| 46 throw new InvalidOperationException("The promise is already resolved"); | |
|
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47 return false; |
| 119 | 48 } |
|
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fixed Resove method bug when calling it on already cancelled promise
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49 return true; |
| 119 | 50 } |
| 51 | |
| 52 protected void EndSetResult() { | |
| 53 CompleteTransit(SUCCEEDED_STATE); | |
| 54 OnSuccess(); | |
| 55 } | |
| 56 | |
| 57 | |
| 58 | |
| 59 /// <summary> | |
| 60 /// Выполняет обещание, сообщая об ошибке | |
| 61 /// </summary> | |
| 62 /// <remarks> | |
| 63 /// Поскольку обещание должно работать в многопточной среде, при его выполнении сразу несколько потоков | |
| 64 /// могу вернуть ошибку, при этом только первая будет использована в качестве результата, остальные | |
| 65 /// будут проигнорированы. | |
| 66 /// </remarks> | |
| 67 /// <param name="error">Исключение возникшее при выполнении операции</param> | |
| 68 /// <exception cref="InvalidOperationException">Данное обещание уже выполнено</exception> | |
| 69 protected void SetError(Exception error) { | |
| 70 if (BeginTransit()) { | |
| 71 m_error = error is PromiseTransientException ? error.InnerException : error; | |
| 72 CompleteTransit(REJECTED_STATE); | |
| 73 OnError(); | |
| 74 } else { | |
| 75 WaitTransition(); | |
| 76 if (m_state == SUCCEEDED_STATE) | |
| 77 throw new InvalidOperationException("The promise is already resolved"); | |
| 78 } | |
| 79 } | |
| 80 | |
| 81 /// <summary> | |
| 82 /// Отменяет операцию, если это возможно. | |
| 83 /// </summary> | |
| 84 /// <remarks>Для определения была ли операция отменена следует использовать свойство <see cref="IsCancelled"/>.</remarks> | |
| 85 protected void SetCancelled() { | |
| 86 if (BeginTransit()) { | |
| 87 CompleteTransit(CANCELLED_STATE); | |
| 88 OnCancelled(); | |
| 89 } | |
| 90 } | |
| 91 | |
| 92 protected abstract void SignalSuccess(THandler handler); | |
| 93 | |
| 94 protected abstract void SignalError(THandler handler, Exception error); | |
| 95 | |
| 96 protected abstract void SignalCancelled(THandler handler); | |
| 97 | |
| 98 void OnSuccess() { | |
| 125 | 99 var hp = m_handlerPointer; |
| 100 var slot = hp +1 ; | |
| 101 while (slot < m_handlersCommited) { | |
| 102 if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) == hp) { | |
| 103 SignalSuccess(m_handlers[slot]); | |
| 104 } | |
| 105 hp = m_handlerPointer; | |
| 106 slot = hp +1 ; | |
| 107 } | |
| 108 | |
| 109 | |
| 110 if (m_extraHandlers != null) { | |
| 111 THandler handler; | |
| 112 while (m_extraHandlers.TryDequeue(out handler)) | |
| 113 SignalSuccess(handler); | |
| 114 } | |
| 119 | 115 } |
| 116 | |
| 117 void OnError() { | |
| 125 | 118 var hp = m_handlerPointer; |
| 119 var slot = hp +1 ; | |
| 120 while (slot < m_handlersCommited) { | |
| 121 if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) == hp) { | |
| 122 SignalError(m_handlers[slot],m_error); | |
| 123 } | |
| 124 hp = m_handlerPointer; | |
| 125 slot = hp +1 ; | |
| 126 } | |
| 127 | |
| 128 if (m_extraHandlers != null) { | |
| 129 THandler handler; | |
| 130 while (m_extraHandlers.TryDequeue(out handler)) | |
| 131 SignalError(handler, m_error); | |
| 132 } | |
| 119 | 133 } |
| 134 | |
| 135 void OnCancelled() { | |
| 125 | 136 var hp = m_handlerPointer; |
| 137 var slot = hp +1 ; | |
| 138 while (slot < m_handlersCommited) { | |
| 139 if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) == hp) { | |
| 140 SignalCancelled(m_handlers[slot]); | |
| 141 } | |
| 142 hp = m_handlerPointer; | |
| 143 slot = hp +1 ; | |
| 144 } | |
| 145 | |
| 146 if (m_extraHandlers != null) { | |
| 147 THandler handler; | |
| 148 while (m_extraHandlers.TryDequeue(out handler)) | |
| 149 SignalCancelled(handler); | |
| 150 } | |
| 119 | 151 } |
| 152 | |
| 153 #endregion | |
| 154 | |
| 155 protected abstract void Listen(PromiseEventType events, Action handler); | |
| 156 | |
| 157 #region synchronization traits | |
| 158 protected void WaitResult(int timeout) { | |
| 159 if (!IsResolved) { | |
| 160 var lk = new object(); | |
| 161 | |
| 162 Listen(PromiseEventType.All, () => { | |
| 163 lock(lk) { | |
| 164 Monitor.Pulse(lk); | |
| 165 } | |
| 166 }); | |
| 167 | |
| 168 lock (lk) { | |
| 169 while(!IsResolved) { | |
| 170 if(!Monitor.Wait(lk,timeout)) | |
| 171 throw new TimeoutException(); | |
| 172 } | |
| 173 } | |
| 174 | |
| 175 } | |
| 176 switch (m_state) { | |
| 177 case SUCCEEDED_STATE: | |
| 178 return; | |
| 179 case CANCELLED_STATE: | |
| 180 throw new OperationCanceledException(); | |
| 181 case REJECTED_STATE: | |
| 182 throw new TargetInvocationException(m_error); | |
| 183 default: | |
| 184 throw new ApplicationException(String.Format("Invalid promise state {0}", m_state)); | |
| 185 } | |
| 186 } | |
| 187 #endregion | |
| 188 | |
| 189 #region handlers managment | |
| 190 | |
| 191 protected void AddHandler(THandler handler) { | |
| 192 | |
| 125 | 193 if (m_state > 1) { |
| 119 | 194 // the promise is in the resolved state, just invoke the handler |
| 125 | 195 InvokeHandler(handler); |
| 196 } else { | |
| 197 var slot = Interlocked.Increment(ref m_handlersCount) - 1; | |
| 198 | |
| 199 if (slot < RESERVED_HANDLERS_COUNT) { | |
| 200 m_handlers[slot] = handler; | |
| 201 | |
| 202 while (slot != Interlocked.CompareExchange(ref m_handlersCommited, slot + 1, slot)) { | |
| 203 } | |
| 119 | 204 |
| 125 | 205 if (m_state > 1) { |
| 206 do { | |
| 207 var hp = m_handlerPointer; | |
| 208 slot = hp + 1; | |
| 209 if (slot < m_handlersCommited) { | |
| 210 if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) != hp) | |
| 211 continue; | |
| 212 InvokeHandler(m_handlers[slot]); | |
| 213 } | |
| 214 break; | |
| 215 } while(true); | |
| 216 } | |
| 217 } else { | |
| 218 if (slot == RESERVED_HANDLERS_COUNT) { | |
| 219 m_extraHandlers = new MTQueue<THandler>(); | |
| 220 } else { | |
| 221 while (m_extraHandlers == null) | |
| 222 Thread.MemoryBarrier(); | |
| 223 } | |
| 119 | 224 |
| 125 | 225 m_extraHandlers.Enqueue(handler); |
| 226 | |
| 227 if (m_state > 1 && m_extraHandlers.TryDequeue(out handler)) | |
| 119 | 228 // if the promise have been resolved while we was adding the handler to the queue |
| 229 // we can't guarantee that someone is still processing it | |
| 230 // therefore we need to fetch a handler from the queue and execute it | |
| 231 // note that fetched handler may be not the one that we have added | |
| 232 // even we can fetch no handlers at all :) | |
| 233 InvokeHandler(handler); | |
| 125 | 234 } |
| 119 | 235 } |
| 236 } | |
| 237 | |
| 238 protected void InvokeHandler(THandler handler) { | |
| 239 switch (m_state) { | |
| 240 case SUCCEEDED_STATE: | |
| 241 SignalSuccess(handler); | |
| 242 break; | |
| 243 case CANCELLED_STATE: | |
| 244 SignalCancelled(handler); | |
| 245 break; | |
| 246 case REJECTED_STATE: | |
| 247 SignalError(handler, m_error); | |
| 248 break; | |
| 249 default: | |
| 250 throw new Exception(String.Format("Invalid promise state {0}", m_state)); | |
| 251 } | |
| 252 } | |
| 253 | |
| 254 #endregion | |
| 255 | |
| 256 #region IPromise implementation | |
| 257 | |
| 258 public void Join(int timeout) { | |
| 259 WaitResult(timeout); | |
| 260 } | |
| 261 | |
| 262 public void Join() { | |
| 263 WaitResult(-1); | |
| 264 } | |
| 265 | |
| 266 public bool IsResolved { | |
| 267 get { | |
| 268 Thread.MemoryBarrier(); | |
| 269 return m_state > 1; | |
| 270 } | |
| 271 } | |
| 272 | |
| 273 public bool IsCancelled { | |
| 274 get { | |
| 275 Thread.MemoryBarrier(); | |
| 276 return m_state == CANCELLED_STATE; | |
| 277 } | |
| 278 } | |
| 279 | |
| 280 #endregion | |
| 281 | |
| 282 #region ICancellable implementation | |
| 283 | |
| 284 public void Cancel() { | |
| 285 SetCancelled(); | |
| 286 } | |
| 287 | |
| 288 #endregion | |
| 289 } | |
| 290 } | |
| 291 |