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using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Data.SqlClient;
using System.Linq.Expressions;
using System.IO;
using System.Reflection;
using System.Text;
using System.Transactions;
namespace System.Data.Linq.SqlClient {
using System.Data.Linq;
using System.Data.Linq.Provider;
internal class SqlConnectionManager : IConnectionManager {
private IProvider provider;
private DbConnection connection;
private bool autoClose;
private bool disposeConnection; // should we dispose this connection when the context is disposed?
private DbTransaction transaction;
private Transaction systemTransaction;
private SqlInfoMessageEventHandler infoMessagehandler;
private List<IConnectionUser> users;
private int maxUsers;
internal SqlConnectionManager(IProvider provider, DbConnection con, int maxUsers, bool disposeConnection) {
this.provider = provider;
this.connection = con;
this.maxUsers = maxUsers;
this.infoMessagehandler = new SqlInfoMessageEventHandler(this.OnInfoMessage);
this.users = new List<IConnectionUser>(maxUsers);
this.disposeConnection = disposeConnection;
}
public DbConnection UseConnection(IConnectionUser user) {
if (user == null) {
throw Error.ArgumentNull("user");
}
if (this.connection.State == ConnectionState.Closed) {
this.connection.Open();
this.autoClose = true;
this.AddInfoMessageHandler();
if (System.Transactions.Transaction.Current != null) {
System.Transactions.Transaction.Current.TransactionCompleted += this.OnTransactionCompleted;
}
}
if (this.transaction == null && System.Transactions.Transaction.Current != null &&
System.Transactions.Transaction.Current != systemTransaction) {
this.ClearConnection();
systemTransaction = System.Transactions.Transaction.Current;
this.connection.EnlistTransaction(System.Transactions.Transaction.Current);
}
if (this.users.Count == this.maxUsers) {
this.BootUser(this.users[0]);
}
this.users.Add(user);
return this.connection;
}
private void BootUser(IConnectionUser user) {
bool saveAutoClose = this.autoClose;
this.autoClose = false;
int index = this.users.IndexOf(user);
if (index >= 0) {
this.users.RemoveAt(index);
}
user.CompleteUse();
this.autoClose = saveAutoClose;
}
internal DbConnection Connection {
get { return this.connection; }
}
internal int MaxUsers {
get { return this.maxUsers; }
}
internal void DisposeConnection() {
// only close this guy if we opened it in the first place
if (this.autoClose) {
this.CloseConnection();
}
// If we created the connection, we need to dispose it even if the user explicitly
// opened it using the Connection property on the context.
if (this.connection != null && this.disposeConnection) {
this.connection.Dispose();
this.connection = null;
}
}
internal void ClearConnection() {
while (this.users.Count > 0) {
this.BootUser(this.users[0]);
}
}
internal bool AutoClose {
get { return this.autoClose; }
set { this.autoClose = value; }
}
internal DbTransaction Transaction {
get { return this.transaction; }
set {
if (value != this.transaction) {
if (value != null) {
if (this.connection != value.Connection) {
throw Error.TransactionDoesNotMatchConnection();
}
}
this.transaction = value;
}
}
}
public void ReleaseConnection(IConnectionUser user) {
if (user == null) {
throw Error.ArgumentNull("user");
}
int index = this.users.IndexOf(user);
if (index >= 0) {
this.users.RemoveAt(index);
}
if (this.users.Count == 0 && this.autoClose && this.transaction == null && System.Transactions.Transaction.Current == null) {
this.CloseConnection();
}
}
private void CloseConnection() {
if (this.connection != null && this.connection.State != ConnectionState.Closed) {
this.connection.Close();
}
this.RemoveInfoMessageHandler();
this.autoClose = false;
}
private void OnInfoMessage(object sender, SqlInfoMessageEventArgs args) {
if (this.provider.Log != null) {
this.provider.Log.WriteLine(Strings.LogGeneralInfoMessage(args.Source, args.Message));
}
}
private void OnTransactionCompleted(object sender, System.Transactions.TransactionEventArgs args) {
if (this.users.Count == 0 && this.autoClose) {
this.CloseConnection();
}
}
private void AddInfoMessageHandler() {
SqlConnection scon = this.connection as SqlConnection;
if (scon != null) {
scon.InfoMessage += this.infoMessagehandler;
}
}
private void RemoveInfoMessageHandler() {
SqlConnection scon = this.connection as SqlConnection;
if (scon != null) {
scon.InfoMessage -= this.infoMessagehandler;
}
}
}
}
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