If a lock is held or acquired and then released within a method, it should be released along all execution paths.
Failing to do so could make an application deadlock-prone because there is a risk of the lock not being released.
The types tracked by the rule are: Monitor, Mutex, ReaderWriterLock, ReaderWriterLockSlim and
SpinLock from the System.Threading namespace.
Noncompliant Code Example
Class Example
Private obj As Object = New Object()
Public Sub DoSomethingWithMonitor()
Monitor.Enter(obj) ' Noncompliant
If IsInitialized() Then
' ..
Monitor.Exit(obj)
End If
End Sub
Private lockObj As ReaderWriterLockSlim = New ReaderWriterLockSlim()
Public Sub DoSomethingWithReaderWriteLockSlim()
lockObj.EnterReadLock() ' Noncompliant
If IsInitialized() Then
' ..
lockObj.ExitReadLock()
End If
End Sub
End Class
Compliant Solution
Class Example
Private obj As Object = New Object()
Public Sub DoSomethingWithMonitor()
SyncLock obj ' is easier to use than explicit Monitor calls
If IsInitialized() Then
End If
End SyncLock
End Sub
Private lockObj As ReaderWriterLockSlim = New ReaderWriterLockSlim()
Public Sub DoSomethingWithReaderWriteLockSlim()
lockObj.EnterReadLock()
Try
If IsInitialized() Then
End If
Finally
lockObj.ExitReadLock()
End Try
End Sub
End Class
See
