public void ExitUpgradeableReadLock()
{
RuntimeHelpers.PrepareConstrainedRegions();
try {}
finally {
ThreadLockState ctstate = CurrentThreadState;
if (!ctstate.LockState.Has(LockState.Upgradable | LockState.Read))
{
throw new SynchronizationLockException("The current thread has not entered the lock in upgradable mode");
}
if (--ctstate.UpgradeableRecursiveCount == 0)
{
upgradableTaken.Value = false;
upgradableEvent.Set();
ctstate.LockState &= ~LockState.Upgradable;
if (Interlocked.Add(ref rwlock, -RwRead) >> RwReadBit == 0)
{
readerDoneEvent.Set();
}
}
}
}
public void ExitWriteLock()
{
RuntimeHelpers.PrepareConstrainedRegions();
try {}
finally {
ThreadLockState ctstate = CurrentThreadState;
if (!ctstate.LockState.Has(LockState.Write))
{
throw new SynchronizationLockException("The current thread has not entered the lock in write mode");
}
if (--ctstate.WriterRecursiveCount == 0)
{
bool isUpgradable = ctstate.LockState.Has(LockState.Upgradable);
ctstate.LockState ^= LockState.Write;
int value = Interlocked.Add(ref rwlock, isUpgradable ? RwRead - RwWrite : -RwWrite);
writerDoneEvent.Set();
if (isUpgradable && value >> RwReadBit == 1)
{
readerDoneEvent.Reset();
}
}
}
}
bool CheckState(ThreadLockState state, int millisecondsTimeout, LockState validState)
{
if (disposed)
{
throw new ObjectDisposedException("ReaderWriterLockSlim");
}
if (millisecondsTimeout < -1)
{
throw new ArgumentOutOfRangeException("millisecondsTimeout");
}
// Detect and prevent recursion
LockState ctstate = state.LockState;
if (ctstate != LockState.None && noRecursion && (ctstate != LockState.Upgradable || validState == LockState.Upgradable))
{
throw new LockRecursionException("The current thread has already a lock and recursion isn't supported");
}
if (noRecursion)
{
return(false);
}
// If we already had right lock state, just return
if (ctstate.Has(validState))
{
return(true);
}
CheckRecursionAuthorization(ctstate, validState);
return(false);
}
private ThreadLockState GetGlobalThreadState()
{
var currentThreadState = TypeHelper.LazyCreateNew(ref _currentThreadState);
if (!currentThreadState.TryGetValue(_id, out var state))
{
currentThreadState[_id] = state = new ThreadLockState();
}
return(state);
}
private ThreadLockState GetGlobalThreadState()
{
if (_currentThreadState == null)
{
Interlocked.CompareExchange(ref _currentThreadState, new Dictionary <int, ThreadLockState>(), null);
}
if (!_currentThreadState.TryGetValue(_id, out var state))
{
_currentThreadState[_id] = state = new ThreadLockState();
}
return(state);
}
//
// Taking the Upgradable read lock is like taking a read lock
// but we limit it to a single upgradable at a time.
//
public bool TryEnterUpgradeableReadLock(int millisecondsTimeout)
{
ThreadLockState ctstate = CurrentThreadState;
if (CheckState(ctstate, millisecondsTimeout, LockState.Upgradable))
{
++ctstate.UpgradeableRecursiveCount;
return(true);
}
if (ctstate.LockState.Has(LockState.Read))
{
throw new LockRecursionException("The current thread has already entered read mode");
}
++numUpgradeWaiters;
long start = millisecondsTimeout == -1 ? 0 : sw.ElapsedMilliseconds;
// We first try to obtain the upgradeable right
while (!upgradableEvent.IsSet() || !upgradableTaken.TryRelaxedSet())
{
if (millisecondsTimeout != -1 && (sw.ElapsedMilliseconds - start) > millisecondsTimeout)
{
--numUpgradeWaiters;
return(false);
}
upgradableEvent.Wait(ComputeTimeout(millisecondsTimeout, start));
}
upgradableEvent.Reset();
// Then it's a simple reader lock acquiring
if (TryEnterReadLock(ComputeTimeout(millisecondsTimeout, start)))
{
ctstate.LockState = LockState.Upgradable;
--numUpgradeWaiters;
--ctstate.ReaderRecursiveCount;
++ctstate.UpgradeableRecursiveCount;
return(true);
}
upgradableTaken.Value = false;
upgradableEvent.Set();
--numUpgradeWaiters;
return(false);
}
ThreadLockState GetGlobalThreadState(int tid)
{
if (currentThreadState == null)
{
Interlocked.CompareExchange(ref currentThreadState, new Dictionary <int, ThreadLockState> (), null);
}
ThreadLockState state;
if (!currentThreadState.TryGetValue(id, out state))
{
currentThreadState [id] = state = new ThreadLockState();
}
return(state);
}
public void ExitReadLock()
{
ThreadLockState ctstate = CurrentThreadState;
if (!ctstate.LockState.Has(LockState.Read))
{
throw new SynchronizationLockException("The current thread has not entered the lock in read mode");
}
ctstate.LockState ^= LockState.Read;
--ctstate.ReaderRecursiveCount;
if (Interlocked.Add(ref rwlock, -RwRead) >> RwReadBit == 0)
{
readerDoneEvent.Set();
}
}
public void ExitUpgradeableReadLock()
{
ThreadLockState ctstate = CurrentThreadState;
if (!ctstate.LockState.Has(LockState.Upgradable | LockState.Read))
{
throw new SynchronizationLockException("The current thread has not entered the lock in upgradable mode");
}
upgradableTaken.Value = false;
upgradableEvent.Set();
ctstate.LockState ^= LockState.Upgradable;
--ctstate.UpgradeableRecursiveCount;
if (Interlocked.Add(ref rwlock, -RwRead) >> RwReadBit == 0)
{
readerDoneEvent.Set();
}
}
private bool CheckState(ThreadLockState state, int millisecondsTimeout, LockState validState)
{
if (_disposed)
{
throw new ObjectDisposedException(nameof(ReaderWriterLockSlim));
}
if (millisecondsTimeout < -1)
{
throw new ArgumentOutOfRangeException(nameof(millisecondsTimeout));
}
// Detect and prevent recursion
var stateLockState = state.LockState;
if (stateLockState != LockState.None && _noRecursion && (!stateLockState.Has(LockState.Upgradable) || validState == LockState.Upgradable))
{
throw new LockRecursionException("The current thread has already a lock and recursion isn't supported");
}
if (_noRecursion)
{
return(false);
}
// If we already had right lock state, just return
if (stateLockState.Has(validState))
{
return(true);
}
// In read mode you can just enter Read recursively
if (stateLockState == LockState.Read)
{
throw new LockRecursionException();
}
return(false);
}
public void ExitReadLock()
{
RuntimeHelpers.PrepareConstrainedRegions();
try {}
finally {
ThreadLockState ctstate = CurrentThreadState;
if (!ctstate.LockState.Has(LockState.Read))
{
throw new SynchronizationLockException("The current thread has not entered the lock in read mode");
}
if (--ctstate.ReaderRecursiveCount == 0)
{
ctstate.LockState ^= LockState.Read;
if (Interlocked.Add(ref rwlock, -RwRead) >> RwReadBit == 0)
{
readerDoneEvent.Set();
}
}
}
}
public void ExitWriteLock()
{
ThreadLockState ctstate = CurrentThreadState;
if (!ctstate.LockState.Has(LockState.Write))
{
throw new SynchronizationLockException("The current thread has not entered the lock in write mode");
}
bool isUpgradable = ctstate.LockState.Has(LockState.Upgradable);
ctstate.LockState ^= LockState.Write;
--ctstate.WriterRecursiveCount;
int value = Interlocked.Add(ref rwlock, isUpgradable ? RwRead - RwWrite : -RwWrite);
writerDoneEvent.Set();
if (isUpgradable && value >> RwReadBit == 1)
{
readerDoneEvent.Reset();
}
}
ThreadLockState GetGlobalThreadState(int tid)
{
if (currentThreadState == null)
Interlocked.CompareExchange(ref currentThreadState, new Dictionary<int, ThreadLockState>(), null);
ThreadLockState state;
if (!currentThreadState.TryGetValue(id, out state))
currentThreadState[id] = state = new ThreadLockState();
return state;
}
bool CheckState (int millisecondsTimeout, ThreadLockState validState)
{
if (disposed)
throw new ObjectDisposedException ("ReaderWriterLockSlim");
if (millisecondsTimeout < Timeout.Infinite)
throw new ArgumentOutOfRangeException ("millisecondsTimeout");
// Detect and prevent recursion
ThreadLockState ctstate = CurrentThreadState;
if (recursionPolicy == LockRecursionPolicy.NoRecursion)
if ((ctstate != ThreadLockState.None && ctstate != ThreadLockState.Upgradable)
|| (ctstate == ThreadLockState.Upgradable && validState == ThreadLockState.Upgradable))
throw new LockRecursionException ("The current thread has already a lock and recursion isn't supported");
// If we already had right lock state, just return
if (ctstate == validState)
return true;
CheckRecursionAuthorization (ctstate, validState);
return false;
}
//
// Taking the Upgradable read lock is like taking a read lock
// but we limit it to a single upgradable at a time.
//
public bool TryEnterUpgradeableReadLock(int millisecondsTimeout)
{
ThreadLockState ctstate = CurrentThreadState;
if (CheckState(ctstate, millisecondsTimeout, LockState.Upgradable))
{
++ctstate.UpgradeableRecursiveCount;
return(true);
}
if (ctstate.LockState.Has(LockState.Read))
{
throw new LockRecursionException("The current thread has already entered read mode");
}
++numUpgradeWaiters;
long start = millisecondsTimeout == -1 ? 0 : sw.ElapsedMilliseconds;
bool taken = false;
bool success = false;
// We first try to obtain the upgradeable right
try {
while (!upgradableEvent.IsSet() || !taken)
{
try {}
finally {
taken = upgradableTaken.TryRelaxedSet();
}
if (taken)
{
break;
}
if (millisecondsTimeout != -1 && (sw.ElapsedMilliseconds - start) > millisecondsTimeout)
{
--numUpgradeWaiters;
return(false);
}
upgradableEvent.Wait(ComputeTimeout(millisecondsTimeout, start));
}
upgradableEvent.Reset();
RuntimeHelpers.PrepareConstrainedRegions();
try {
// Then it's a simple reader lock acquiring
TryEnterReadLock(ComputeTimeout(millisecondsTimeout, start), ref success);
} finally {
if (success)
{
ctstate.LockState |= LockState.Upgradable;
ctstate.LockState &= ~LockState.Read;
--ctstate.ReaderRecursiveCount;
++ctstate.UpgradeableRecursiveCount;
}
else
{
upgradableTaken.Value = false;
upgradableEvent.Set();
}
}
--numUpgradeWaiters;
} catch {
// An async exception occured, if we had taken the upgradable mode, release it
if (taken && !success)
{
upgradableTaken.Value = false;
}
}
return(success);
}
static void CheckRecursionAuthorization (ThreadLockState ctstate, ThreadLockState desiredState)
{
// In read mode you can just enter Read recursively
if (ctstate == ThreadLockState.Read)
throw new LockRecursionException ();
}
public bool TryEnterWriteLock(int millisecondsTimeout)
{
ThreadLockState ctstate = CurrentThreadState;
if (CheckState(ctstate, millisecondsTimeout, LockState.Write))
{
++ctstate.WriterRecursiveCount;
return(true);
}
++numWriteWaiters;
bool isUpgradable = ctstate.LockState.Has(LockState.Upgradable);
bool registered = false;
bool success = false;
RuntimeHelpers.PrepareConstrainedRegions();
try {
/* If the code goes there that means we had a read lock beforehand
* that need to be suppressed, we also take the opportunity to register
* our interest in the write lock to avoid other write wannabe process
* coming in the middle
*/
if (isUpgradable && rwlock >= RwRead)
{
try {}
finally {
if (Interlocked.Add(ref rwlock, RwWaitUpgrade - RwRead) >> RwReadBit == 0)
{
readerDoneEvent.Set();
}
registered = true;
}
}
int stateCheck = isUpgradable ? RwWaitUpgrade + RwWait : RwWait;
long start = millisecondsTimeout == -1 ? 0 : sw.ElapsedMilliseconds;
int registration = isUpgradable ? RwWaitUpgrade : RwWait;
do
{
int state = rwlock;
if (state <= stateCheck)
{
try {}
finally {
var toWrite = state + RwWrite - (registered ? registration : 0);
if (Interlocked.CompareExchange(ref rwlock, toWrite, state) == state)
{
writerDoneEvent.Reset();
ctstate.LockState ^= LockState.Write;
++ctstate.WriterRecursiveCount;
--numWriteWaiters;
registered = false;
success = true;
}
}
if (success)
{
return(true);
}
}
state = rwlock;
// We register our interest in taking the Write lock (if upgradeable it's already done)
if (!isUpgradable)
{
while ((state & RwWait) == 0)
{
try {}
finally {
if (Interlocked.CompareExchange(ref rwlock, state | RwWait, state) == state)
{
registered = true;
}
}
if (registered)
{
break;
}
state = rwlock;
}
}
// Before falling to sleep
do
{
if (rwlock <= stateCheck)
{
break;
}
if ((rwlock & RwWrite) != 0)
{
writerDoneEvent.Wait(ComputeTimeout(millisecondsTimeout, start));
}
else if ((rwlock >> RwReadBit) > 0)
{
readerDoneEvent.Wait(ComputeTimeout(millisecondsTimeout, start));
}
} while (millisecondsTimeout < 0 || (sw.ElapsedMilliseconds - start) < millisecondsTimeout);
} while (millisecondsTimeout < 0 || (sw.ElapsedMilliseconds - start) < millisecondsTimeout);
--numWriteWaiters;
} finally {
if (registered)
{
Interlocked.Add(ref rwlock, isUpgradable ? -RwWaitUpgrade : -RwWait);
}
}
return(false);
}
bool TryEnterReadLock(int millisecondsTimeout, ref bool success)
{
ThreadLockState ctstate = CurrentThreadState;
if (CheckState(ctstate, millisecondsTimeout, LockState.Read))
{
++ctstate.ReaderRecursiveCount;
return(true);
}
// This is downgrading from upgradable, no need for check since
// we already have a sort-of read lock that's going to disappear
// after user calls ExitUpgradeableReadLock.
// Same idea when recursion is allowed and a write thread wants to
// go for a Read too.
if (ctstate.LockState.Has(LockState.Upgradable) ||
(!noRecursion && ctstate.LockState.Has(LockState.Write)))
{
RuntimeHelpers.PrepareConstrainedRegions();
try {}
finally {
Interlocked.Add(ref rwlock, RwRead);
ctstate.LockState |= LockState.Read;
++ctstate.ReaderRecursiveCount;
success = true;
}
return(true);
}
++numReadWaiters;
int val = 0;
long start = millisecondsTimeout == -1 ? 0 : sw.ElapsedMilliseconds;
do
{
/* Check if a writer is present (RwWrite) or if there is someone waiting to
* acquire a writer lock in the queue (RwWait | RwWaitUpgrade).
*/
if ((rwlock & (RwWrite | RwWait | RwWaitUpgrade)) > 0)
{
writerDoneEvent.Wait(ComputeTimeout(millisecondsTimeout, start));
continue;
}
/* Optimistically try to add ourselves to the reader value
* if the adding was too late and another writer came in between
* we revert the operation.
*/
RuntimeHelpers.PrepareConstrainedRegions();
try {}
finally {
if (((val = Interlocked.Add(ref rwlock, RwRead)) & (RwWrite | RwWait | RwWaitUpgrade)) == 0)
{
/* If we are the first reader, reset the event to let other threads
* sleep correctly if they try to acquire write lock
*/
if (val >> RwReadBit == 1)
{
readerDoneEvent.Reset();
}
ctstate.LockState ^= LockState.Read;
++ctstate.ReaderRecursiveCount;
--numReadWaiters;
success = true;
}
else
{
Interlocked.Add(ref rwlock, -RwRead);
}
}
if (success)
{
return(true);
}
writerDoneEvent.Wait(ComputeTimeout(millisecondsTimeout, start));
} while (millisecondsTimeout == -1 || (sw.ElapsedMilliseconds - start) < millisecondsTimeout);
--numReadWaiters;
return(false);
}
bool CheckState(ThreadLockState state, int millisecondsTimeout, LockState validState)
{
if (disposed)
throw new ObjectDisposedException("ReaderWriterLockSlim");
if (millisecondsTimeout < -1)
throw new ArgumentOutOfRangeException("millisecondsTimeout");
// Detect and prevent recursion
LockState ctstate = state.LockState;
if (ctstate != LockState.None && noRecursion && (!ctstate.Has(LockState.Upgradable) || validState == LockState.Upgradable))
throw new LockRecursionException("The current thread has already a lock and recursion isn't supported");
if (noRecursion)
return false;
// If we already had right lock state, just return
if (ctstate.Has(validState))
return true;
// In read mode you can just enter Read recursively
if (ctstate == LockState.Read)
throw new LockRecursionException();
return false;
}
internal static bool Has (this ThreadLockState state, ThreadLockState value)
{
return (state & value) > 0;
}
