///////////////////////////////////////////////////////////////////////
/// <summary>
/// Disposes of all pooled connections.
/// </summary>
internal static void ClearAllPools()
{
lock (_syncRoot)
{
foreach (KeyValuePair <string, PoolQueue> pair in _queueList)
{
if (pair.Value == null)
{
continue;
}
Queue <WeakReference> poolQueue = pair.Value.Queue;
while (poolQueue.Count > 0)
{
WeakReference connection = poolQueue.Dequeue();
if (connection == null)
{
continue;
}
SmbClient handle =
connection.Target as SmbClient;
if (handle != null)
{
handle.Dispose();
}
GC.KeepAlive(handle);
}
//
// NOTE: Keep track of the highest revision so we can
// go one higher when we are finished.
//
if (_poolVersion <= pair.Value.PoolVersion)
{
_poolVersion = pair.Value.PoolVersion + 1;
}
}
//
// NOTE: All pools are cleared and we have a new highest
// version number to force all old version active
// items to get discarded instead of going back to
// the queue when they are closed. We can get away
// with this because we have pumped up the pool
// version out of range of all active connections,
// so they will all get discarded when they try to
// put themselves back into their pools.
//
_queueList.Clear();
}
}
public static SmbClient GetSmbClient(string path)
{
var client = SmbConnectionPool.Remove(MakeKey(path), 5, out _poolVersion);
if (client == null)
{
client = new SmbClient(path);
}
return(client);
}
/// <summary>
/// We do not have to thread-lock anything in this function, because it
/// is only called by other functions above which already take the lock.
/// </summary>
/// <param name="queue">
/// The pool queue to resize.
/// </param>
/// <param name="add">
/// If a function intends to add to the pool, this is true, which
/// forces the resize to take one more than it needs from the pool.
/// </param>
private static void ResizePool(
PoolQueue queue,
bool add
)
{
int target = queue.MaxPoolSize;
if (add && target > 0)
{
target--;
}
Queue <WeakReference> poolQueue = queue.Queue;
if (poolQueue == null)
{
return;
}
while (poolQueue.Count > target)
{
WeakReference connection = poolQueue.Dequeue();
if (connection == null)
{
continue;
}
SmbClient handle =
connection.Target as SmbClient;
if (handle != null)
{
handle.Dispose();
}
GC.KeepAlive(handle);
}
}
///////////////////////////////////////////////////////////////////////
/// <summary>
/// Disposes of all pooled connections associated with the specified
/// database file name.
/// </summary>
/// <param name="fileName">
/// The database file name.
/// </param>
internal static void ClearPool(string fileName)
{
lock (_syncRoot)
{
PoolQueue queue;
if (_queueList.TryGetValue(fileName, out queue))
{
queue.PoolVersion++;
Queue <WeakReference> poolQueue = queue.Queue;
if (poolQueue == null)
{
return;
}
while (poolQueue.Count > 0)
{
WeakReference connection = poolQueue.Dequeue();
if (connection == null)
{
continue;
}
SmbClient handle =
connection.Target as SmbClient;
if (handle != null)
{
handle.Dispose();
}
GC.KeepAlive(handle);
}
}
}
}
///////////////////////////////////////////////////////////////////////
/// <summary>
/// Adds a connection to the pool of those associated with the
/// specified database file name.
/// </summary>
/// <param name="fileName">
/// The database file name.
/// </param>
/// <param name="handle">
/// The database connection handle.
/// </param>
/// <param name="version">
/// The connection pool version at the point the database connection
/// handle was received from the connection pool. This is also the
/// connection pool version that the database connection handle was
/// created under.
/// </param>
internal static void Add(
string fileName,
SmbClient handle,
int version
)
{
lock (_syncRoot)
{
//
// NOTE: If the queue does not exist in the pool, then it
// must have been cleared sometime after the
// connection was created.
//
PoolQueue queue;
if (_queueList.TryGetValue(fileName, out queue) &&
version == queue.PoolVersion)
{
ResizePool(queue, true);
Queue <WeakReference> poolQueue = queue.Queue;
if (poolQueue == null)
{
return;
}
poolQueue.Enqueue(new WeakReference(handle, false));
Interlocked.Increment(ref _poolClosed);
}
else
{
handle.Close();
}
GC.KeepAlive(handle);
}
}
///////////////////////////////////////////////////////////////////////
/// <summary>
/// Removes a connection from the pool of those associated with the
/// specified database file name with the intent of using it to
/// interact with the database.
/// </summary>
/// <param name="fileName">
/// The database file name.
/// </param>
/// <param name="maxPoolSize">
/// The new maximum size of the connection pool for the specified
/// database file name.
/// </param>
/// <param name="version">
/// The connection pool version associated with the returned database
/// connection handle, if any.
/// </param>
/// <returns>
/// The database connection handle associated with the specified
/// database file name or null if it cannot be obtained.
/// </returns>
internal static SmbClient Remove(
string fileName,
int maxPoolSize,
out int version
)
{
int localVersion;
Queue <WeakReference> poolQueue;
//
// NOTE: This lock cannot be held while checking the queue for
// available connections because other methods of this
// class are called from the GC finalizer thread and we
// use the WaitForPendingFinalizers method (below).
// Holding this lock while calling that method would
// therefore result in a deadlock. Instead, this lock
// is held only while a temporary copy of the queue is
// created, and if necessary, when committing changes
// back to that original queue prior to returning from
// this method.
//
lock (_syncRoot)
{
PoolQueue queue;
//
// NOTE: Default to the highest pool version.
//
version = _poolVersion;
//
// NOTE: If we didn't find a pool for this file, create one
// even though it will be empty. We have to do this
// here because otherwise calling ClearPool() on the
// file will not work for active connections that have
// never seen the pool yet.
//
if (!_queueList.TryGetValue(fileName, out queue))
{
queue = new PoolQueue(_poolVersion, maxPoolSize);
_queueList.Add(fileName, queue);
return(null);
}
//
// NOTE: We found a pool for this file, so use its version
// number.
//
version = localVersion = queue.PoolVersion;
queue.MaxPoolSize = maxPoolSize;
//
// NOTE: Now, resize the pool to the new maximum size, if
// necessary.
//
ResizePool(queue, false);
//
// NOTE: Try and get a pooled connection from the queue.
//
poolQueue = queue.Queue;
if (poolQueue == null)
{
return(null);
}
//
// NOTE: Temporarily tranfer the queue for this file into
// a local variable. The queue for this file will
// be modified and then committed back to the real
// pool list (below) prior to returning from this
// method.
//
_queueList.Remove(fileName);
poolQueue = new Queue <WeakReference>(poolQueue);
}
try
{
while (poolQueue.Count > 0)
{
WeakReference connection = poolQueue.Dequeue();
if (connection == null)
{
continue;
}
SmbClient handle =
connection.Target as SmbClient;
if (handle == null)
{
continue;
}
//
// BUGFIX: For ticket [996d13cd87], step #1. After
// this point, make sure that the finalizer for
// the connection handle just obtained from the
// queue cannot START running (i.e. it may
// still be pending but it will no longer start
// after this point).
//
GC.SuppressFinalize(handle);
try
{
//
// BUGFIX: For ticket [996d13cd87], step #2. Now,
// we must wait for all pending finalizers
// which have STARTED running and have not
// yet COMPLETED. This must be done just
// in case the finalizer for the connection
// handle just obtained from the queue has
// STARTED running at some point before
// SuppressFinalize was called on it.
//
// After this point, checking properties of
// the connection handle (e.g. IsClosed)
// should work reliably without having to
// worry that they will (due to the
// finalizer) change out from under us.
//
GC.WaitForPendingFinalizers();
//
// BUGFIX: For ticket [996d13cd87], step #3. Next,
// verify that the connection handle is
// actually valid and [still?] not closed
// prior to actually returning it to our
// caller.
//
if (!handle.IsClosed)
{
Interlocked.Increment(ref _poolOpened);
return(handle);
}
}
finally
{
//
// BUGFIX: For ticket [996d13cd87], step #4. Next,
// we must re-register the connection
// handle for finalization now that we have
// a strong reference to it (i.e. the
// finalizer will not run at least until
// the connection is subsequently closed).
//
GC.ReRegisterForFinalize(handle);
}
GC.KeepAlive(handle);
}
}
finally
{
//
// BUGFIX: For ticket [996d13cd87], step #5. Finally,
// commit any changes to the pool/queue for this
// database file.
//
lock (_syncRoot)
{
//
// NOTE: We must check [again] if a pool exists for
// this file because one may have been added
// while the search for an available connection
// was in progress (above).
//
PoolQueue queue;
Queue <WeakReference> newPoolQueue;
bool addPool;
if (_queueList.TryGetValue(fileName, out queue))
{
addPool = false;
}
else
{
addPool = true;
queue = new PoolQueue(localVersion, maxPoolSize);
}
newPoolQueue = queue.Queue;
while (poolQueue.Count > 0)
{
newPoolQueue.Enqueue(poolQueue.Dequeue());
}
ResizePool(queue, false);
if (addPool)
{
_queueList.Add(fileName, queue);
}
}
}
return(null);
}
public SmbStream(SmbClient cifsClient, object handle, FileAccess fileAccess)
{
_cifsClient = cifsClient;
_handle = handle;
_fileAccess = fileAccess;
}
