public SQLiteDataReaderED(DbCommand cmd, CommandBehavior behaviour, SQLiteTransactionED <TConn> txn = null, SQLiteTxnLockED <TConn> txnlock = null)
{
this._command = cmd;
this.InnerReader = cmd.ExecuteReader(behaviour);
this._transaction = txn;
this._txnlock = txnlock;
}
public void OpenReader()
{
if (_owningThread != Thread.CurrentThread)
{
throw new InvalidOperationException("Transaction lock passed between threads");
}
if (!_lock.IsWriteLockHeld)
{
if (!_isReader)
{
try
{
Interlocked.Increment(ref _readsWaiting);
while (!_lock.TryEnterReadLock(1000))
{
SQLiteTxnLockED <TConn> lockowner = _writeLockOwner;
if (lockowner != null)
{
Trace.WriteLine($"Thread {Thread.CurrentThread.Name} waiting for thread {lockowner._owningThread.Name} to finish writer");
DebugLongRunningOperation(lockowner);
}
}
_isReader = true;
}
finally
{
Interlocked.Decrement(ref _readsWaiting);
}
}
}
}
private static void DebugLongRunningOperation(SQLiteTxnLockED <TConn> txnlock)
{
if (txnlock != null)
{
txnlock._isLongRunning = true;
if (txnlock._commandExecuting)
{
if (txnlock._isLongRunning)
{
Trace.WriteLine($"The following command is taking a long time to execute:\n{txnlock._commandText}");
}
if (txnlock._owningThread == Thread.CurrentThread)
{
StackTrace trace = new StackTrace(1, true);
Trace.WriteLine(trace.ToString());
}
}
else
{
Trace.WriteLine($"The transaction lock has been held for a long time.");
if (txnlock._commandText != null)
{
Trace.WriteLine($"Last command to execute:\n{txnlock._commandText}");
}
}
}
}
// disposing: true if Dispose() was called, false
// if being finalized by the garbage collector
protected override void Dispose(bool disposing)
{
if (disposing)
{
if (_cn != null)
{
_cn.Close();
_cn.Dispose();
_cn = null;
}
if (_schemaLock.IsReadLockHeld)
{
_schemaLock.ExitReadLock();
}
if (_transactionLock != null)
{
_transactionLock.Dispose();
_transactionLock = null;
}
}
base.Dispose(disposing);
}
public SQLiteCommandED(DbCommand cmd, SQLiteConnectionED conn, SQLiteTxnLockED <TConn> txnlock, DbTransaction txn = null)
{
_connection = conn;
_txnlock = txnlock;
InnerCommand = cmd;
if (txn != null)
{
SetTransaction(txn);
}
}
public override void Close()
{
InnerReader.Close();
if (_txnlock != null)
{
_txnlock.CloseReader();
_txnlock = null;
}
}
public SQLiteConnectionED(EDDSqlDbSelection?maindb = null, bool utctimeindicator = false, bool initializing = false, bool shortlived = true)
: base(initializing)
{
bool locktaken = false;
try
{
if (!initializing && !_initialized)
{
System.Diagnostics.Trace.WriteLine($"Database {typeof(TConn).Name} initialized before Initialize()");
System.Diagnostics.Trace.WriteLine(new System.Diagnostics.StackTrace(2, true).ToString());
if (typeof(TConn) == typeof(SQLiteConnectionUser))
{
SQLiteConnectionUser.Initialize();
}
else if (typeof(TConn) == typeof(SQLiteConnectionSystem))
{
SQLiteConnectionSystem.Initialize();
}
}
_schemaLock.EnterReadLock();
locktaken = true;
// System.Threading.Monitor.Enter(monitor);
//Console.WriteLine("Connection open " + System.Threading.Thread.CurrentThread.Name);
DBFile = GetSQLiteDBFile(maindb ?? EDDSqlDbSelection.EDDUser);
_cn = DbFactory.CreateConnection();
// Use the database selected by maindb as the 'main' database
_cn.ConnectionString = "Data Source=" + DBFile + ";Pooling=true;";
if (utctimeindicator) // indicate treat dates as UTC.
{
_cn.ConnectionString += "DateTimeKind=Utc;";
}
_transactionLock = new SQLiteTxnLockED <TConn>();
_cn.Open();
}
catch
{
if (_transactionLock != null)
{
_transactionLock.Dispose();
}
if (locktaken)
{
_schemaLock.ExitReadLock();
}
throw;
}
}
public void OpenWriter()
{
if (_owningThread != Thread.CurrentThread)
{
throw new InvalidOperationException("Transaction lock passed between threads");
}
if (_lock.IsReadLockHeld)
{
throw new InvalidOperationException("Write attempted in read-only connection");
}
if (!_isWriter)
{
try
{
if (!_lock.IsUpgradeableReadLockHeld)
{
while (!_lock.TryEnterUpgradeableReadLock(1000))
{
SQLiteTxnLockED <TConn> lockowner = _writeLockOwner;
if (lockowner != null)
{
Trace.WriteLine($"Thread {Thread.CurrentThread.Name} waiting for thread {lockowner._owningThread.Name} to finish writer");
DebugLongRunningOperation(lockowner);
}
}
_isWriter = true;
_writeLockOwner = this;
}
while (!_lock.TryEnterWriteLock(1000))
{
Trace.WriteLine($"Thread {Thread.CurrentThread.Name} waiting for readers to finish");
}
}
catch
{
if (_isWriter)
{
if (_lock.IsWriteLockHeld)
{
_lock.ExitWriteLock();
}
if (_lock.IsUpgradeableReadLockHeld)
{
_lock.ExitUpgradeableReadLock();
}
}
}
}
}
private static void DebugLongRunningOperation(object state)
{
WeakReference weakref = state as WeakReference;
if (weakref != null)
{
SQLiteTxnLockED <TConn> txnlock = weakref.Target as SQLiteTxnLockED <TConn>;
DebugLongRunningOperation(txnlock);
}
}
public SQLiteConnectionED(EDDSqlDbSelection?maindb = null, bool utctimeindicator = false, bool initializing = false, bool shortlived = true)
: base(initializing)
{
bool locktaken = false;
try
{
_schemaLock.EnterReadLock();
locktaken = true;
// System.Threading.Monitor.Enter(monitor);
//Console.WriteLine("Connection open " + System.Threading.Thread.CurrentThread.Name);
DBFile = GetSQLiteDBFile(maindb ?? SQLiteDBClass.DefaultMainDatabase);
_cn = SQLiteDBClass.CreateCN();
// Use the database selected by maindb as the 'main' database
_cn.ConnectionString = "Data Source=" + DBFile + ";Pooling=true;";
if (utctimeindicator) // indicate treat dates as UTC.
{
_cn.ConnectionString += "DateTimeKind=Utc;";
}
_transactionLock = new SQLiteTxnLockED <TConn>();
_cn.Open();
}
catch
{
if (_transactionLock != null)
{
_transactionLock.Dispose();
}
if (locktaken)
{
_schemaLock.ExitReadLock();
}
throw;
}
}
public DbTransaction BeginTransaction()
{
// Take the transaction lock before beginning the
// transaction to avoid a deadlock
var txnlock = new SQLiteTxnLockED();
txnlock.Open();
return new SQLiteTransactionED(_cn.BeginTransaction(), txnlock);
}
public SQLiteTransactionED(DbTransaction txn, SQLiteTxnLockED <TConn> txnlock)
{
_transactionLock = txnlock;
InnerTransaction = txn;
}
public SQLiteDataReaderED(DbCommand cmd, CommandBehavior behaviour, SQLiteTransactionED txn = null, SQLiteTxnLockED txnlock = null)
{
this._command = cmd;
this.InnerReader = cmd.ExecuteReader(behaviour);
this._transaction = txn;
this._txnlock = txnlock;
}
protected override DbDataReader ExecuteDbDataReader(CommandBehavior behavior)
{
if (this._transaction != null)
{
// The transaction should already have the transaction lock
return new SQLiteDataReaderED(this.InnerCommand, behavior, txn: this._transaction);
}
else
{
// Take the transaction lock for the duration of this command
using (var txnlock = new SQLiteTxnLockED())
{
txnlock.Open();
return new SQLiteDataReaderED(this.InnerCommand, behavior, txnlock: txnlock);
}
}
}
// disposing: true if Dispose() was called, false
// if being finalized by the garbage collector
protected override void Dispose(bool disposing)
{
if (disposing)
{
// Close the transaction before closing the lock
if (InnerTransaction != null)
{
InnerTransaction.Dispose();
InnerTransaction = null;
}
if (_transactionLock != null)
{
_transactionLock.Dispose();
_transactionLock = null;
}
}
base.Dispose(disposing);
}
public SQLiteTransactionED(DbTransaction txn, SQLiteTxnLockED txnlock)
{
_transactionLock = txnlock;
InnerTransaction = txn;
}
public override object ExecuteScalar()
{
if (this._transaction != null)
{
this._transaction.BeginCommand(this);
// The transaction should already have the transaction lock
object result = InnerCommand.ExecuteScalar();
this._transaction.EndCommand();
return result;
}
else
{
// Take the transaction lock for the duration of this command
using (var txnlock = new SQLiteTxnLockED())
{
txnlock.Open();
txnlock.BeginCommand(this);
object result = InnerCommand.ExecuteScalar();
txnlock.EndCommand();
return result;
}
}
}
