Mercurial > pub > ImplabNet
annotate Implab/AbstractEvent.cs @ 185:822aab37b107 ref20160224
runnable component, work in progress
| author | cin |
|---|---|
| date | Mon, 18 Apr 2016 16:41:17 +0300 |
| parents | 5802131432e4 |
| children | 75103928da09 |
| rev | line source |
|---|---|
| 144 | 1 using System; |
| 2 using Implab.Parallels; | |
| 3 using System.Threading; | |
| 4 using System.Reflection; | |
| 5 | |
| 6 namespace Implab { | |
| 145 | 7 public abstract class AbstractEvent<THandler> : ICancellationToken, 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; |
| 144 | 27 MTQueue<THandler> m_extraHandlers; |
| 28 int m_handlerPointer = -1; | |
| 29 int m_handlersCommited; | |
| 30 | |
| 31 int m_cancelRequest; | |
| 32 Exception m_cancelationReason; | |
| 33 MTQueue<Action<Exception>> m_cancelationHandlers; | |
| 34 | |
| 35 | |
| 36 #region state managment | |
| 37 bool BeginTransit() { | |
| 38 return UNRESOLVED_SATE == Interlocked.CompareExchange(ref m_state, TRANSITIONAL_STATE, UNRESOLVED_SATE); | |
| 39 } | |
| 40 | |
| 41 void CompleteTransit(int state) { | |
| 42 if (TRANSITIONAL_STATE != Interlocked.CompareExchange(ref m_state, state, TRANSITIONAL_STATE)) | |
| 43 throw new InvalidOperationException("Can't complete transition when the object isn't in the transitional state"); | |
| 44 } | |
| 45 | |
| 46 void WaitTransition() { | |
| 47 while (m_state == TRANSITIONAL_STATE) { | |
| 48 Thread.MemoryBarrier(); | |
| 49 } | |
| 50 } | |
| 51 | |
| 52 protected bool BeginSetResult() { | |
| 53 if (!BeginTransit()) { | |
| 54 WaitTransition(); | |
| 55 if (m_state != CANCELLED_STATE) | |
| 56 throw new InvalidOperationException("The promise is already resolved"); | |
| 57 return false; | |
| 58 } | |
| 59 return true; | |
| 60 } | |
| 61 | |
| 62 protected void EndSetResult() { | |
| 63 CompleteTransit(SUCCEEDED_STATE); | |
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64 Signal(); |
| 144 | 65 } |
| 66 | |
| 67 | |
| 68 | |
| 69 /// <summary> | |
| 70 /// Выполняет обещание, сообщая об ошибке | |
| 71 /// </summary> | |
| 72 /// <remarks> | |
| 73 /// Поскольку обещание должно работать в многопточной среде, при его выполнении сразу несколько потоков | |
| 74 /// могу вернуть ошибку, при этом только первая будет использована в качестве результата, остальные | |
| 75 /// будут проигнорированы. | |
| 76 /// </remarks> | |
| 77 /// <param name="error">Исключение возникшее при выполнении операции</param> | |
| 78 /// <exception cref="InvalidOperationException">Данное обещание уже выполнено</exception> | |
| 79 protected void SetError(Exception error) { | |
| 185 | 80 while (error is PromiseTransientException) |
| 81 error = error.InnerException; | |
| 82 | |
| 83 var isCancel = error is OperationCanceledException; | |
| 84 | |
| 144 | 85 if (BeginTransit()) { |
| 185 | 86 m_error = isCancel ? error.InnerException : error; |
| 87 CompleteTransit(isCancel ? CANCELLED_STATE : REJECTED_STATE); | |
| 88 | |
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89 Signal(); |
| 144 | 90 } else { |
| 91 WaitTransition(); | |
| 185 | 92 if (!isCancel || m_state == SUCCEEDED_STATE) |
| 144 | 93 throw new InvalidOperationException("The promise is already resolved"); |
| 94 } | |
| 95 } | |
| 96 | |
| 97 /// <summary> | |
| 98 /// Отменяет операцию, если это возможно. | |
| 99 /// </summary> | |
| 100 /// <remarks>Для определения была ли операция отменена следует использовать свойство <see cref="IsCancelled"/>.</remarks> | |
| 101 protected void SetCancelled(Exception reason) { | |
| 102 if (BeginTransit()) { | |
| 103 m_error = reason; | |
| 104 CompleteTransit(CANCELLED_STATE); | |
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105 Signal(); |
| 144 | 106 } |
| 107 } | |
| 108 | |
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109 protected abstract void SignalHandler(THandler handler, int signal); |
| 144 | 110 |
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111 void Signal() { |
| 144 | 112 var hp = m_handlerPointer; |
| 113 var slot = hp +1 ; | |
| 114 while (slot < m_handlersCommited) { | |
| 115 if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) == hp) { | |
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116 SignalHandler(m_handlers[slot], m_state); |
| 144 | 117 } |
| 118 hp = m_handlerPointer; | |
| 119 slot = hp +1 ; | |
| 120 } | |
| 121 | |
| 122 | |
| 123 if (m_extraHandlers != null) { | |
| 124 THandler handler; | |
| 125 while (m_extraHandlers.TryDequeue(out handler)) | |
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126 SignalHandler(handler, m_state); |
| 144 | 127 } |
| 128 } | |
| 129 | |
| 130 #endregion | |
| 131 | |
| 132 protected abstract Signal GetResolveSignal(); | |
| 133 | |
| 134 #region synchronization traits | |
| 135 protected void WaitResult(int timeout) { | |
| 148 | 136 if (!(IsResolved || GetResolveSignal().Wait(timeout))) |
| 137 throw new TimeoutException(); | |
| 144 | 138 |
| 139 switch (m_state) { | |
| 140 case SUCCEEDED_STATE: | |
| 141 return; | |
| 142 case CANCELLED_STATE: | |
| 143 throw new OperationCanceledException(); | |
| 144 case REJECTED_STATE: | |
| 145 throw new TargetInvocationException(m_error); | |
| 146 default: | |
| 147 throw new ApplicationException(String.Format("Invalid promise state {0}", m_state)); | |
| 148 } | |
| 149 } | |
| 150 #endregion | |
| 151 | |
| 152 #region handlers managment | |
| 153 | |
| 154 protected void AddHandler(THandler handler) { | |
| 155 | |
| 156 if (m_state > 1) { | |
| 157 // the promise is in the resolved state, just invoke the handler | |
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158 SignalHandler(handler, m_state); |
| 144 | 159 } else { |
| 160 var slot = Interlocked.Increment(ref m_handlersCount) - 1; | |
| 161 | |
| 162 if (slot < RESERVED_HANDLERS_COUNT) { | |
| 163 | |
| 160 | 164 if (slot == 0) { |
| 165 m_handlers = new THandler[RESERVED_HANDLERS_COUNT]; | |
| 166 } else { | |
| 167 while (m_handlers == null) | |
| 168 Thread.MemoryBarrier(); | |
| 169 } | |
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170 |
| 144 | 171 m_handlers[slot] = handler; |
| 172 | |
| 173 while (slot != Interlocked.CompareExchange(ref m_handlersCommited, slot + 1, slot)) { | |
| 174 } | |
| 175 | |
| 176 if (m_state > 1) { | |
| 177 do { | |
| 178 var hp = m_handlerPointer; | |
| 179 slot = hp + 1; | |
| 180 if (slot < m_handlersCommited) { | |
| 181 if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) != hp) | |
| 182 continue; | |
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183 SignalHandler(m_handlers[slot], m_state); |
| 144 | 184 } |
| 185 break; | |
| 186 } while(true); | |
| 187 } | |
| 188 } else { | |
| 189 if (slot == RESERVED_HANDLERS_COUNT) { | |
| 190 m_extraHandlers = new MTQueue<THandler>(); | |
| 191 } else { | |
| 192 while (m_extraHandlers == null) | |
| 193 Thread.MemoryBarrier(); | |
| 194 } | |
| 195 | |
| 196 m_extraHandlers.Enqueue(handler); | |
| 197 | |
| 198 if (m_state > 1 && m_extraHandlers.TryDequeue(out handler)) | |
| 199 // if the promise have been resolved while we was adding the handler to the queue | |
| 200 // we can't guarantee that someone is still processing it | |
| 201 // therefore we need to fetch a handler from the queue and execute it | |
| 202 // note that fetched handler may be not the one that we have added | |
| 203 // even we can fetch no handlers at all :) | |
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204 SignalHandler(handler, m_state); |
| 144 | 205 } |
| 206 } | |
| 207 } | |
| 208 | |
| 209 #endregion | |
| 210 | |
| 211 #region IPromise implementation | |
| 212 | |
| 213 public bool IsResolved { | |
| 214 get { | |
| 215 Thread.MemoryBarrier(); | |
| 216 return m_state > 1; | |
| 217 } | |
| 218 } | |
| 219 | |
| 220 public bool IsCancelled { | |
| 221 get { | |
| 222 Thread.MemoryBarrier(); | |
| 223 return m_state == CANCELLED_STATE; | |
| 224 } | |
| 225 } | |
| 226 | |
| 227 #endregion | |
| 228 | |
| 229 public Exception Error { | |
| 230 get { | |
| 231 return m_error; | |
| 232 } | |
| 233 } | |
| 234 | |
| 145 | 235 public bool CancelOperationIfRequested() { |
| 236 if (IsCancellationRequested) { | |
| 237 CancelOperation(CancellationReason); | |
| 238 return true; | |
| 239 } | |
| 240 return false; | |
| 144 | 241 } |
| 242 | |
| 243 public virtual void CancelOperation(Exception reason) { | |
| 244 SetCancelled(reason); | |
| 245 } | |
| 246 | |
| 145 | 247 public void CancellationRequested(Action<Exception> handler) { |
| 144 | 248 Safe.ArgumentNotNull(handler, "handler"); |
| 145 | 249 if (IsCancellationRequested) |
| 250 handler(CancellationReason); | |
| 144 | 251 |
| 252 if (m_cancelationHandlers == null) | |
| 253 Interlocked.CompareExchange(ref m_cancelationHandlers, new MTQueue<Action<Exception>>(), null); | |
| 254 | |
| 255 m_cancelationHandlers.Enqueue(handler); | |
| 256 | |
| 145 | 257 if (IsCancellationRequested && m_cancelationHandlers.TryDequeue(out handler)) |
| 144 | 258 // TryDeque implies MemoryBarrier() |
| 259 handler(m_cancelationReason); | |
| 260 } | |
| 261 | |
| 145 | 262 public bool IsCancellationRequested { |
| 144 | 263 get { |
| 264 do { | |
| 265 if (m_cancelRequest == CANCEL_NOT_REQUESTED) | |
| 266 return false; | |
| 267 if (m_cancelRequest == CANCEL_REQUESTED) | |
| 268 return true; | |
| 269 Thread.MemoryBarrier(); | |
| 270 } while(true); | |
| 271 } | |
| 272 } | |
| 273 | |
| 145 | 274 public Exception CancellationReason { |
| 144 | 275 get { |
| 276 do { | |
| 277 Thread.MemoryBarrier(); | |
| 278 } while(m_cancelRequest == CANCEL_REQUESTING); | |
| 279 | |
| 280 return m_cancelationReason; | |
| 281 } | |
| 282 } | |
| 283 | |
| 284 #region ICancellable implementation | |
| 285 | |
| 286 public void Cancel() { | |
| 287 Cancel(null); | |
| 288 } | |
| 289 | |
| 290 public void Cancel(Exception reason) { | |
| 145 | 291 if (CANCEL_NOT_REQUESTED == Interlocked.CompareExchange(ref m_cancelRequest, CANCEL_REQUESTING, CANCEL_NOT_REQUESTED)) { |
| 144 | 292 m_cancelationReason = reason; |
| 293 m_cancelRequest = CANCEL_REQUESTED; | |
| 294 if (m_cancelationHandlers != null) { | |
| 295 Action<Exception> handler; | |
| 296 while (m_cancelationHandlers.TryDequeue(out handler)) | |
| 297 handler(m_cancelationReason); | |
| 298 } | |
| 299 } | |
| 300 } | |
| 301 | |
| 302 #endregion | |
| 303 } | |
| 304 } | |
| 305 |