|
|
using System;
|
|
|
using Implab.Parallels;
|
|
|
using System.Threading;
|
|
|
using System.Reflection;
|
|
|
|
|
|
namespace Implab {
|
|
|
public abstract class AbstractPromise<THandler> {
|
|
|
|
|
|
const int UNRESOLVED_SATE = 0;
|
|
|
const int TRANSITIONAL_STATE = 1;
|
|
|
const int SUCCEEDED_STATE = 2;
|
|
|
const int REJECTED_STATE = 3;
|
|
|
const int CANCELLED_STATE = 4;
|
|
|
|
|
|
const int RESERVED_HANDLERS_COUNT = 4;
|
|
|
|
|
|
int m_state;
|
|
|
Exception m_error;
|
|
|
int m_handlersCount;
|
|
|
|
|
|
readonly THandler[] m_handlers = new THandler[RESERVED_HANDLERS_COUNT];
|
|
|
MTQueue<THandler> m_extraHandlers;
|
|
|
int m_handlerPointer = -1;
|
|
|
int m_handlersCommited;
|
|
|
|
|
|
#region state managment
|
|
|
bool BeginTransit() {
|
|
|
return UNRESOLVED_SATE == Interlocked.CompareExchange(ref m_state, TRANSITIONAL_STATE, UNRESOLVED_SATE);
|
|
|
}
|
|
|
|
|
|
void CompleteTransit(int state) {
|
|
|
if (TRANSITIONAL_STATE != Interlocked.CompareExchange(ref m_state, state, TRANSITIONAL_STATE))
|
|
|
throw new InvalidOperationException("Can't complete transition when the object isn't in the transitional state");
|
|
|
}
|
|
|
|
|
|
void WaitTransition() {
|
|
|
while (m_state == TRANSITIONAL_STATE) {
|
|
|
Thread.MemoryBarrier();
|
|
|
}
|
|
|
}
|
|
|
|
|
|
protected bool BeginSetResult() {
|
|
|
if (!BeginTransit()) {
|
|
|
WaitTransition();
|
|
|
if (m_state != CANCELLED_STATE)
|
|
|
throw new InvalidOperationException("The promise is already resolved");
|
|
|
return false;
|
|
|
}
|
|
|
return true;
|
|
|
}
|
|
|
|
|
|
protected void EndSetResult() {
|
|
|
CompleteTransit(SUCCEEDED_STATE);
|
|
|
OnSuccess();
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/// <summary>
|
|
|
/// Выполняет обещание, сообщая об ошибке
|
|
|
/// </summary>
|
|
|
/// <remarks>
|
|
|
/// Поскольку обещание должно работать в многопточной среде, при его выполнении сразу несколько потоков
|
|
|
/// могу вернуть ошибку, при этом только первая будет использована в качестве результата, остальные
|
|
|
/// будут проигнорированы.
|
|
|
/// </remarks>
|
|
|
/// <param name="error">Исключение возникшее при выполнении операции</param>
|
|
|
/// <exception cref="InvalidOperationException">Данное обещание уже выполнено</exception>
|
|
|
protected void SetError(Exception error) {
|
|
|
if (BeginTransit()) {
|
|
|
if (error is OperationCanceledException) {
|
|
|
CompleteTransit(CANCELLED_STATE);
|
|
|
m_error = error.InnerException;
|
|
|
OnCancelled();
|
|
|
} else {
|
|
|
m_error = error is PromiseTransientException ? error.InnerException : error;
|
|
|
CompleteTransit(REJECTED_STATE);
|
|
|
OnError();
|
|
|
}
|
|
|
} else {
|
|
|
WaitTransition();
|
|
|
if (m_state == SUCCEEDED_STATE)
|
|
|
throw new InvalidOperationException("The promise is already resolved");
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// <summary>
|
|
|
/// Отменяет операцию, если это возможно.
|
|
|
/// </summary>
|
|
|
/// <remarks>Для определения была ли операция отменена следует использовать свойство <see cref="IsCancelled"/>.</remarks>
|
|
|
protected void SetCancelled(Exception reason) {
|
|
|
if (BeginTransit()) {
|
|
|
m_error = reason;
|
|
|
CompleteTransit(CANCELLED_STATE);
|
|
|
OnCancelled();
|
|
|
}
|
|
|
}
|
|
|
|
|
|
protected abstract void SignalSuccess(THandler handler);
|
|
|
|
|
|
protected abstract void SignalError(THandler handler, Exception error);
|
|
|
|
|
|
protected abstract void SignalCancelled(THandler handler, Exception reason);
|
|
|
|
|
|
void OnSuccess() {
|
|
|
var hp = m_handlerPointer;
|
|
|
var slot = hp +1 ;
|
|
|
while (slot < m_handlersCommited) {
|
|
|
if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) == hp) {
|
|
|
SignalSuccess(m_handlers[slot]);
|
|
|
}
|
|
|
hp = m_handlerPointer;
|
|
|
slot = hp +1 ;
|
|
|
}
|
|
|
|
|
|
|
|
|
if (m_extraHandlers != null) {
|
|
|
THandler handler;
|
|
|
while (m_extraHandlers.TryDequeue(out handler))
|
|
|
SignalSuccess(handler);
|
|
|
}
|
|
|
}
|
|
|
|
|
|
void OnError() {
|
|
|
var hp = m_handlerPointer;
|
|
|
var slot = hp +1 ;
|
|
|
while (slot < m_handlersCommited) {
|
|
|
if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) == hp) {
|
|
|
SignalError(m_handlers[slot],m_error);
|
|
|
}
|
|
|
hp = m_handlerPointer;
|
|
|
slot = hp +1 ;
|
|
|
}
|
|
|
|
|
|
if (m_extraHandlers != null) {
|
|
|
THandler handler;
|
|
|
while (m_extraHandlers.TryDequeue(out handler))
|
|
|
SignalError(handler, m_error);
|
|
|
}
|
|
|
}
|
|
|
|
|
|
void OnCancelled() {
|
|
|
var hp = m_handlerPointer;
|
|
|
var slot = hp +1 ;
|
|
|
while (slot < m_handlersCommited) {
|
|
|
if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) == hp) {
|
|
|
SignalCancelled(m_handlers[slot], m_error);
|
|
|
}
|
|
|
hp = m_handlerPointer;
|
|
|
slot = hp +1 ;
|
|
|
}
|
|
|
|
|
|
if (m_extraHandlers != null) {
|
|
|
THandler handler;
|
|
|
while (m_extraHandlers.TryDequeue(out handler))
|
|
|
SignalCancelled(handler, m_error);
|
|
|
}
|
|
|
}
|
|
|
|
|
|
#endregion
|
|
|
|
|
|
protected abstract void Listen(PromiseEventType events, Action handler);
|
|
|
|
|
|
#region synchronization traits
|
|
|
protected void WaitResult(int timeout) {
|
|
|
if (!IsResolved) {
|
|
|
var lk = new object();
|
|
|
|
|
|
Listen(PromiseEventType.All, () => {
|
|
|
lock(lk) {
|
|
|
Monitor.Pulse(lk);
|
|
|
}
|
|
|
});
|
|
|
|
|
|
lock (lk) {
|
|
|
while(!IsResolved) {
|
|
|
if(!Monitor.Wait(lk,timeout))
|
|
|
throw new TimeoutException();
|
|
|
}
|
|
|
}
|
|
|
|
|
|
}
|
|
|
switch (m_state) {
|
|
|
case SUCCEEDED_STATE:
|
|
|
return;
|
|
|
case CANCELLED_STATE:
|
|
|
throw new OperationCanceledException();
|
|
|
case REJECTED_STATE:
|
|
|
throw new TargetInvocationException(m_error);
|
|
|
default:
|
|
|
throw new ApplicationException(String.Format("Invalid promise state {0}", m_state));
|
|
|
}
|
|
|
}
|
|
|
#endregion
|
|
|
|
|
|
#region handlers managment
|
|
|
|
|
|
protected void AddHandler(THandler handler) {
|
|
|
|
|
|
if (m_state > 1) {
|
|
|
// the promise is in the resolved state, just invoke the handler
|
|
|
InvokeHandler(handler);
|
|
|
} else {
|
|
|
var slot = Interlocked.Increment(ref m_handlersCount) - 1;
|
|
|
|
|
|
if (slot < RESERVED_HANDLERS_COUNT) {
|
|
|
m_handlers[slot] = handler;
|
|
|
|
|
|
while (slot != Interlocked.CompareExchange(ref m_handlersCommited, slot + 1, slot)) {
|
|
|
}
|
|
|
|
|
|
if (m_state > 1) {
|
|
|
do {
|
|
|
var hp = m_handlerPointer;
|
|
|
slot = hp + 1;
|
|
|
if (slot < m_handlersCommited) {
|
|
|
if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) != hp)
|
|
|
continue;
|
|
|
InvokeHandler(m_handlers[slot]);
|
|
|
}
|
|
|
break;
|
|
|
} while(true);
|
|
|
}
|
|
|
} else {
|
|
|
if (slot == RESERVED_HANDLERS_COUNT) {
|
|
|
m_extraHandlers = new MTQueue<THandler>();
|
|
|
} else {
|
|
|
while (m_extraHandlers == null)
|
|
|
Thread.MemoryBarrier();
|
|
|
}
|
|
|
|
|
|
m_extraHandlers.Enqueue(handler);
|
|
|
|
|
|
if (m_state > 1 && m_extraHandlers.TryDequeue(out handler))
|
|
|
// if the promise have been resolved while we was adding the handler to the queue
|
|
|
// we can't guarantee that someone is still processing it
|
|
|
// therefore we need to fetch a handler from the queue and execute it
|
|
|
// note that fetched handler may be not the one that we have added
|
|
|
// even we can fetch no handlers at all :)
|
|
|
InvokeHandler(handler);
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
|
|
|
protected void InvokeHandler(THandler handler) {
|
|
|
switch (m_state) {
|
|
|
case SUCCEEDED_STATE:
|
|
|
SignalSuccess(handler);
|
|
|
break;
|
|
|
case CANCELLED_STATE:
|
|
|
SignalCancelled(handler, m_error);
|
|
|
break;
|
|
|
case REJECTED_STATE:
|
|
|
SignalError(handler, m_error);
|
|
|
break;
|
|
|
default:
|
|
|
throw new Exception(String.Format("Invalid promise state {0}", m_state));
|
|
|
}
|
|
|
}
|
|
|
|
|
|
#endregion
|
|
|
|
|
|
#region IPromise implementation
|
|
|
|
|
|
public void Join(int timeout) {
|
|
|
WaitResult(timeout);
|
|
|
}
|
|
|
|
|
|
public void Join() {
|
|
|
WaitResult(-1);
|
|
|
}
|
|
|
|
|
|
public bool IsResolved {
|
|
|
get {
|
|
|
Thread.MemoryBarrier();
|
|
|
return m_state > 1;
|
|
|
}
|
|
|
}
|
|
|
|
|
|
public bool IsCancelled {
|
|
|
get {
|
|
|
Thread.MemoryBarrier();
|
|
|
return m_state == CANCELLED_STATE;
|
|
|
}
|
|
|
}
|
|
|
|
|
|
#endregion
|
|
|
|
|
|
public Exception Error {
|
|
|
get {
|
|
|
return m_error;
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
|
|
|
|
