/// <summary>
/// Enter in Shared lock mode.
/// </summary>
public LockControl Read()
{
// if read or write
if (_thread.IsReadLockHeld || _thread.IsWriteLockHeld)
{
return(new LockControl(false, () => { }));
}
// try enter in read mode
if (!_thread.TryEnterReadLock(_timeout))
{
throw LiteException.LockTimeout(_timeout);
}
_log.Write(Logger.LOCK, "entered in read lock mode in thread #{0}", this.ThreadId);
// lock disk in shared mode
var position = _disk.Lock(LockState.Read, _timeout);
var changed = this.DetectDatabaseChanges();
return(new LockControl(changed, () =>
{
// exit disk lock mode
_disk.Unlock(LockState.Read, position);
// exit thread lock mode
_thread.ExitReadLock();
_log.Write(Logger.LOCK, "exited read lock mode in thread #{0}", this.ThreadId);
}));
}
/// <summary>
/// Try execute some action while has lock exception
/// </summary>
public static void TryExec(Action action, TimeSpan timeout)
{
var timer = DateTime.UtcNow.Add(timeout);
do
{
try
{
action();
return;
}
catch (IOException ex)
{
ex.WaitIfLocked(25);
}
}while (DateTime.UtcNow < timer);
throw LiteException.LockTimeout(timeout);
}
/// <summary>
/// Enter in Exclusive lock mode
/// </summary>
public LockControl Write()
{
// if already in exclusive, do nothing
if (_thread.IsWriteLockHeld)
{
return(new LockControl(false, () => { }));
}
// let's test if is not in read lock
if (_thread.IsReadLockHeld)
{
throw new NotSupportedException("Not support Write lock inside a Read lock");
}
// try enter in write mode (thread)
if (!_thread.TryEnterWriteLock(_timeout))
{
throw LiteException.LockTimeout(_timeout);
}
_log.Write(Logger.LOCK, "entered in write lock mode in thread #{0}", this.ThreadId);
// try enter in exclusive mode in disk
var position = _disk.Lock(LockState.Write, _timeout);
// call avoid dirty only if not came from a shared mode
var changed = this.DetectDatabaseChanges();
return(new LockControl(changed, () =>
{
// release disk write
_disk.Unlock(LockState.Write, position);
// release thread write
_thread.ExitWriteLock();
_log.Write(Logger.LOCK, "exited write lock mode in thread #{0}", this.ThreadId);
}));
}