Mercurial > pub > ImplabNet
annotate Implab/AbstractEvent.cs @ 240:fa6cbf4d8841 v3
refactoring, moving to dotnercore, simplifying promises
| author | cin |
|---|---|
| date | Tue, 23 Jan 2018 19:39:21 +0300 |
| parents | d6fe09f5592c |
| children | cbe10ac0731e |
| rev | line source |
|---|---|
| 144 | 1 using System; |
| 2 using Implab.Parallels; | |
| 3 using System.Threading; | |
| 4 using System.Reflection; | |
| 5 | |
| 6 namespace Implab { | |
|
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7 public abstract class AbstractEvent<THandler> : ICancellable { |
| 144 | 8 |
| 9 const int UNRESOLVED_SATE = 0; | |
| 10 const int TRANSITIONAL_STATE = 1; | |
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11 protected const int SUCCEEDED_STATE = 2; |
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12 protected const int REJECTED_STATE = 3; |
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13 protected const int CANCELLED_STATE = 4; |
| 144 | 14 |
| 15 const int CANCEL_NOT_REQUESTED = 0; | |
| 16 const int CANCEL_REQUESTING = 1; | |
| 17 const int CANCEL_REQUESTED = 2; | |
| 18 | |
| 19 const int RESERVED_HANDLERS_COUNT = 4; | |
| 20 | |
| 21 int m_state; | |
| 22 Exception m_error; | |
| 23 int m_handlersCount; | |
| 24 | |
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25 //readonly THandler[] m_handlers = new THandler[RESERVED_HANDLERS_COUNT]; |
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26 THandler[] m_handlers; |
| 233 | 27 SimpleAsyncQueue<THandler> m_extraHandlers; |
| 144 | 28 int m_handlerPointer = -1; |
| 29 int m_handlersCommited; | |
| 30 | |
| 31 int m_cancelRequest; | |
| 32 Exception m_cancelationReason; | |
| 33 | |
| 34 #region state managment | |
| 35 bool BeginTransit() { | |
| 36 return UNRESOLVED_SATE == Interlocked.CompareExchange(ref m_state, TRANSITIONAL_STATE, UNRESOLVED_SATE); | |
| 37 } | |
| 38 | |
| 39 void CompleteTransit(int state) { | |
| 40 if (TRANSITIONAL_STATE != Interlocked.CompareExchange(ref m_state, state, TRANSITIONAL_STATE)) | |
| 41 throw new InvalidOperationException("Can't complete transition when the object isn't in the transitional state"); | |
| 42 } | |
| 43 | |
| 44 void WaitTransition() { | |
| 45 while (m_state == TRANSITIONAL_STATE) { | |
| 46 Thread.MemoryBarrier(); | |
| 47 } | |
| 48 } | |
| 49 | |
| 50 protected bool BeginSetResult() { | |
| 51 if (!BeginTransit()) { | |
| 52 WaitTransition(); | |
| 53 if (m_state != CANCELLED_STATE) | |
| 54 throw new InvalidOperationException("The promise is already resolved"); | |
| 55 return false; | |
| 56 } | |
| 57 return true; | |
| 58 } | |
| 59 | |
| 60 protected void EndSetResult() { | |
| 61 CompleteTransit(SUCCEEDED_STATE); | |
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62 Signal(); |
| 144 | 63 } |
| 64 | |
| 65 | |
| 66 | |
| 67 /// <summary> | |
| 68 /// Выполняет обещание, сообщая об ошибке | |
| 69 /// </summary> | |
| 70 /// <remarks> | |
| 71 /// Поскольку обещание должно работать в многопточной среде, при его выполнении сразу несколько потоков | |
| 72 /// могу вернуть ошибку, при этом только первая будет использована в качестве результата, остальные | |
| 73 /// будут проигнорированы. | |
| 74 /// </remarks> | |
| 75 /// <param name="error">Исключение возникшее при выполнении операции</param> | |
| 76 /// <exception cref="InvalidOperationException">Данное обещание уже выполнено</exception> | |
| 77 protected void SetError(Exception error) { | |
| 78 if (BeginTransit()) { | |
| 186 | 79 m_error = error; |
| 80 CompleteTransit(REJECTED_STATE); | |
| 185 | 81 |
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82 Signal(); |
| 144 | 83 } else { |
| 84 WaitTransition(); | |
| 186 | 85 if (m_state == SUCCEEDED_STATE) |
| 144 | 86 throw new InvalidOperationException("The promise is already resolved"); |
| 87 } | |
| 88 } | |
| 89 | |
| 90 /// <summary> | |
| 91 /// Отменяет операцию, если это возможно. | |
| 92 /// </summary> | |
| 93 /// <remarks>Для определения была ли операция отменена следует использовать свойство <see cref="IsCancelled"/>.</remarks> | |
| 94 protected void SetCancelled(Exception reason) { | |
| 95 if (BeginTransit()) { | |
| 96 m_error = reason; | |
| 97 CompleteTransit(CANCELLED_STATE); | |
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98 Signal(); |
| 144 | 99 } |
| 100 } | |
| 101 | |
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102 protected abstract void SignalHandler(THandler handler, int signal); |
| 144 | 103 |
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104 void Signal() { |
| 144 | 105 var hp = m_handlerPointer; |
| 106 var slot = hp +1 ; | |
| 107 while (slot < m_handlersCommited) { | |
| 108 if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) == hp) { | |
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109 SignalHandler(m_handlers[slot], m_state); |
| 144 | 110 } |
| 111 hp = m_handlerPointer; | |
| 112 slot = hp +1 ; | |
| 113 } | |
| 114 | |
| 115 | |
| 116 if (m_extraHandlers != null) { | |
| 117 THandler handler; | |
| 118 while (m_extraHandlers.TryDequeue(out handler)) | |
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119 SignalHandler(handler, m_state); |
| 144 | 120 } |
| 121 } | |
| 122 | |
| 123 #endregion | |
| 124 | |
| 125 protected abstract Signal GetResolveSignal(); | |
| 126 | |
| 127 #region synchronization traits | |
| 128 protected void WaitResult(int timeout) { | |
| 148 | 129 if (!(IsResolved || GetResolveSignal().Wait(timeout))) |
| 130 throw new TimeoutException(); | |
| 144 | 131 |
| 132 switch (m_state) { | |
| 133 case SUCCEEDED_STATE: | |
| 134 return; | |
| 135 case CANCELLED_STATE: | |
| 186 | 136 throw new OperationCanceledException("The operation has been cancelled", m_error); |
| 144 | 137 case REJECTED_STATE: |
| 138 throw new TargetInvocationException(m_error); | |
| 139 default: | |
| 186 | 140 throw new ApplicationException(String.Format("The promise state {0} is invalid", m_state)); |
| 144 | 141 } |
| 142 } | |
| 143 #endregion | |
| 144 | |
| 145 #region handlers managment | |
| 146 | |
| 147 protected void AddHandler(THandler handler) { | |
| 148 | |
| 149 if (m_state > 1) { | |
| 150 // the promise is in the resolved state, just invoke the handler | |
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151 SignalHandler(handler, m_state); |
| 144 | 152 } else { |
| 153 var slot = Interlocked.Increment(ref m_handlersCount) - 1; | |
| 154 | |
| 155 if (slot < RESERVED_HANDLERS_COUNT) { | |
| 156 | |
| 160 | 157 if (slot == 0) { |
| 158 m_handlers = new THandler[RESERVED_HANDLERS_COUNT]; | |
| 159 } else { | |
| 160 while (m_handlers == null) | |
| 161 Thread.MemoryBarrier(); | |
| 162 } | |
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163 |
| 144 | 164 m_handlers[slot] = handler; |
| 165 | |
| 166 while (slot != Interlocked.CompareExchange(ref m_handlersCommited, slot + 1, slot)) { | |
| 167 } | |
| 168 | |
| 169 if (m_state > 1) { | |
| 170 do { | |
| 171 var hp = m_handlerPointer; | |
| 172 slot = hp + 1; | |
| 173 if (slot < m_handlersCommited) { | |
| 174 if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) != hp) | |
| 175 continue; | |
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176 SignalHandler(m_handlers[slot], m_state); |
| 144 | 177 } |
| 178 break; | |
| 179 } while(true); | |
| 180 } | |
| 181 } else { | |
| 182 if (slot == RESERVED_HANDLERS_COUNT) { | |
| 233 | 183 m_extraHandlers = new SimpleAsyncQueue<THandler>(); |
| 144 | 184 } else { |
| 185 while (m_extraHandlers == null) | |
| 186 Thread.MemoryBarrier(); | |
| 187 } | |
| 188 | |
| 189 m_extraHandlers.Enqueue(handler); | |
| 190 | |
| 191 if (m_state > 1 && m_extraHandlers.TryDequeue(out handler)) | |
| 192 // if the promise have been resolved while we was adding the handler to the queue | |
| 193 // we can't guarantee that someone is still processing it | |
| 194 // therefore we need to fetch a handler from the queue and execute it | |
| 195 // note that fetched handler may be not the one that we have added | |
| 196 // even we can fetch no handlers at all :) | |
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197 SignalHandler(handler, m_state); |
| 144 | 198 } |
| 199 } | |
| 200 } | |
| 201 | |
| 202 #endregion | |
| 203 | |
| 204 #region IPromise implementation | |
| 205 | |
| 206 public bool IsResolved { | |
| 207 get { | |
| 208 Thread.MemoryBarrier(); | |
| 209 return m_state > 1; | |
| 210 } | |
| 211 } | |
| 212 | |
| 213 public bool IsCancelled { | |
| 214 get { | |
| 215 Thread.MemoryBarrier(); | |
| 216 return m_state == CANCELLED_STATE; | |
| 217 } | |
| 218 } | |
| 219 | |
| 220 #endregion | |
| 221 | |
| 222 public Exception Error { | |
| 223 get { | |
| 224 return m_error; | |
| 225 } | |
| 226 } | |
| 227 | |
| 145 | 228 public bool CancelOperationIfRequested() { |
| 229 if (IsCancellationRequested) { | |
| 230 CancelOperation(CancellationReason); | |
| 231 return true; | |
| 232 } | |
| 233 return false; | |
| 144 | 234 } |
| 235 | |
| 236 public virtual void CancelOperation(Exception reason) { | |
| 237 SetCancelled(reason); | |
| 238 } | |
| 239 | |
| 145 | 240 public void CancellationRequested(Action<Exception> handler) { |
| 144 | 241 Safe.ArgumentNotNull(handler, "handler"); |
| 145 | 242 if (IsCancellationRequested) |
| 243 handler(CancellationReason); | |
| 144 | 244 |
| 245 if (m_cancelationHandlers == null) | |
| 233 | 246 Interlocked.CompareExchange(ref m_cancelationHandlers, new SimpleAsyncQueue<Action<Exception>>(), null); |
| 144 | 247 |
| 248 m_cancelationHandlers.Enqueue(handler); | |
| 249 | |
| 145 | 250 if (IsCancellationRequested && m_cancelationHandlers.TryDequeue(out handler)) |
| 144 | 251 // TryDeque implies MemoryBarrier() |
| 252 handler(m_cancelationReason); | |
| 253 } | |
| 254 | |
| 145 | 255 public bool IsCancellationRequested { |
| 144 | 256 get { |
| 257 do { | |
| 258 if (m_cancelRequest == CANCEL_NOT_REQUESTED) | |
| 259 return false; | |
| 260 if (m_cancelRequest == CANCEL_REQUESTED) | |
| 261 return true; | |
| 262 Thread.MemoryBarrier(); | |
| 263 } while(true); | |
| 264 } | |
| 265 } | |
| 266 | |
| 145 | 267 public Exception CancellationReason { |
| 144 | 268 get { |
| 269 do { | |
| 270 Thread.MemoryBarrier(); | |
| 271 } while(m_cancelRequest == CANCEL_REQUESTING); | |
| 272 | |
| 273 return m_cancelationReason; | |
| 274 } | |
| 275 } | |
| 276 | |
| 277 #region ICancellable implementation | |
| 278 | |
| 279 public void Cancel() { | |
| 280 Cancel(null); | |
| 281 } | |
| 282 | |
| 283 public void Cancel(Exception reason) { | |
| 145 | 284 if (CANCEL_NOT_REQUESTED == Interlocked.CompareExchange(ref m_cancelRequest, CANCEL_REQUESTING, CANCEL_NOT_REQUESTED)) { |
| 144 | 285 m_cancelationReason = reason; |
| 286 m_cancelRequest = CANCEL_REQUESTED; | |
| 287 if (m_cancelationHandlers != null) { | |
| 288 Action<Exception> handler; | |
| 289 while (m_cancelationHandlers.TryDequeue(out handler)) | |
| 290 handler(m_cancelationReason); | |
| 291 } | |
| 292 } | |
| 293 } | |
| 294 | |
| 295 #endregion | |
| 296 } | |
| 297 } | |
| 298 |