public Task WaitAsync(OneManyMode mode)
{
// 假定无竞争
Task accressGranter = m_noContentionAccessGranter;
Lock();
switch (mode)
{
case OneManyMode.Exclusive:
if (IsFree)
{
MakeWriter();
}
else
{
// 有竞争： 新的writer任务进入队列，并返回它使writer等待
var tcs = new TaskCompletionSource <object>();
m_qWaitingWriters.Enqueue(tcs);
accressGranter = tcs.Task;
}
break;
case OneManyMode.Shared:
if (IsFree || (IsOwnedByReaders && m_qWaitingWriters.Count == 0))
{
AddReaders(1);
}
else
{
// 竞争：递增等待的reader数量，并返回reader任务使reader等待
m_numWaitingReaders++;
accressGranter = m_waitingReadersSignal.Task.ContinueWith(t =>
{
Console.WriteLine("所有写入完成了，读取开始");
});
}
break;
}
UnLock();
return(accressGranter);
}
/// <summary>
/// Asynchronously requests access to the state protected by this AsyncOneManyLock
/// </summary>
/// <param name="mode">Specifies whether you want exclusive (write) access or shared (read) access.</param>
/// <returns>A Task to await.</returns>
public Task WaitAsync(OneManyMode mode)
{
Task accressGranter = m_noContentionAccessGranter; // Assume no contention
Lock();
switch (mode)
{
case OneManyMode.Exclusive:
if (IsFree)
{
MakeWriter(); // No contention
}
else
{
// Contention: Queue new writer task & return it so writer waits
var tcs = new TaskCompletionSource <object>();
m_qWaitingWriters.Enqueue(tcs);
accressGranter = tcs.Task;
}
break;
case OneManyMode.Shared:
if (IsFree || (IsOwnedByReaders && m_qWaitingWriters.Count == 0))
{
AddReaders(1); // No contention
}
else
{
// Contention: Increment waiting readers & return reader task so reader waits
m_numWaitingReaders++;
accressGranter = m_waitingReadersSignal.Task.ContinueWith(t => t.Result);
}
break;
}
Unlock();
return(accressGranter);
}
public Task WaitAsync(OneManyMode mode)
{
Task accressGranter = m_noContentionAccessGranter;
Lock();
switch (mode)
{
case OneManyMode.Exclusive:
if (IsFree)
{
MakeWriter();
}
else
{
var tcs = new TaskCompletionSource <Object>();
m_qWaitingWriters.Enqueue(tcs);
accressGranter = tcs.Task;
}
break;
case OneManyMode.Shared:
if (IsFree || (IsOwnedByReaders && m_qWaitingWriters.Count == 0))
{
AddReaders(1);
}
else
{
m_numWaitingReader++;
accressGranter = m_waitingReadersSignal.Task.ContinueWith(t => t.Result);
}
break;
}
Unlock();
return(accressGranter);
}
public Task WaitAsync(OneManyMode mode)
{
var accressGranter = _noContentionAccessGranter; // Assume no contention
Lock();
switch (mode)
{
case OneManyMode.Exclusive:
if (IsFree)
{
MakeWriter(); // No contention
}
else
{
// Contention: Queue new writer task & return it so writer waits
var tcs = new TaskCompletionSource<object>();
_qWaitingWriters.Enqueue(tcs);
accressGranter = tcs.Task;
}
break;
case OneManyMode.Shared:
if (IsFree || (IsOwnedByReaders && _qWaitingWriters.Count == 0))
{
AddReaders(1); // No contention
}
else
{
// Contention: Increment waiting readers & return reader task so reader waits
_numWaitingReaders++;
accressGranter = _waitingReadersSignal.Task.ContinueWith(t => t.Result);
}
break;
}
Unlock();
return accressGranter;
}