OdbcConnectionHandle.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Data / System / Data / Odbc / OdbcConnectionHandle.cs / 1305376 / OdbcConnectionHandle.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
// [....]
//----------------------------------------------------------------------------- 
 
using System;
using System.Collections; 
using System.ComponentModel;
using System.Data;
using System.Data.Common;
using System.Diagnostics; 
using System.Globalization;
using System.Runtime.CompilerServices; 
using System.Runtime.InteropServices; 
using System.Security;
using System.Security.Permissions; 
using System.Text;
using System.Threading;
using System.Runtime.ConstrainedExecution;
 
namespace System.Data.Odbc {
 
    sealed internal class OdbcConnectionHandle : OdbcHandle { 
        private HandleState _handleState;
 
        private enum HandleState {
            Allocated = 0,
            Connected = 1,
            Transacted = 2, 
            TransactionInProgress = 3,
        } 
 
        internal OdbcConnectionHandle(OdbcConnection connection, OdbcConnectionString constr, OdbcEnvironmentHandle environmentHandle) : base(ODBC32.SQL_HANDLE.DBC, environmentHandle) {
            if(null == connection) { 
                throw ADP.ArgumentNull("connection");
            }
            if(null == constr) {
                throw ADP.ArgumentNull("constr"); 
            }
 
            ODBC32.RetCode retcode; 

            //Set connection timeout (only before open). 
            //Note: We use login timeout since its odbc 1.0 option, instead of using
            //connectiontimeout (which affects other things besides just login) and its
            //a odbc 3.0 feature.  The ConnectionTimeout on the managed providers represents
            //the login timeout, nothing more. 
            int connectionTimeout = connection.ConnectionTimeout;
            retcode = SetConnectionAttribute2(ODBC32.SQL_ATTR.LOGIN_TIMEOUT, (IntPtr)connectionTimeout, (Int32)ODBC32.SQL_IS.UINTEGER); 
 
            string connectionString = constr.UsersConnectionString(false);
 
            // Connect to the driver.  (Using the connection string supplied)
            //Note: The driver doesn't filter out the password in the returned connection string
            //so their is no need for us to obtain the returned connection string
            // Prepare to handle a ThreadAbort Exception between SQLDriverConnectW and update of the state variables 
            retcode = Connect(connectionString);
            connection.HandleError(this, retcode); 
        } 

        private ODBC32.RetCode AutoCommitOff() { 
            ODBC32.RetCode retcode;

            Debug.Assert(HandleState.Connected <= _handleState, "AutoCommitOff while in wrong state?");
 
            // Avoid runtime injected errors in the following block.
            // must call SQLSetConnectAttrW and set _handleState 
            RuntimeHelpers.PrepareConstrainedRegions(); 
            try {} finally {
                retcode = UnsafeNativeMethods.SQLSetConnectAttrW(this, ODBC32.SQL_ATTR.AUTOCOMMIT, ODBC32.SQL_AUTOCOMMIT_OFF, (Int32)ODBC32.SQL_IS.UINTEGER); 
                switch(retcode) {
                case ODBC32.RetCode.SUCCESS:
                case ODBC32.RetCode.SUCCESS_WITH_INFO:
                    _handleState = HandleState.Transacted; 
                    break;
                } 
            } 
            ODBC.TraceODBC(3, "SQLSetConnectAttrW", retcode);
            return retcode; 
        }

        internal ODBC32.RetCode BeginTransaction(ref IsolationLevel isolevel) {
            ODBC32.RetCode retcode = ODBC32.RetCode.SUCCESS; 
            ODBC32.SQL_ATTR isolationAttribute;
            if(IsolationLevel.Unspecified != isolevel) { 
                ODBC32.SQL_TRANSACTION sql_iso; 
                switch(isolevel) {
                case IsolationLevel.ReadUncommitted: 
                    sql_iso = ODBC32.SQL_TRANSACTION.READ_UNCOMMITTED;
                    isolationAttribute = ODBC32.SQL_ATTR.TXN_ISOLATION;
                    break;
                case IsolationLevel.ReadCommitted: 
                    sql_iso = ODBC32.SQL_TRANSACTION.READ_COMMITTED;
                    isolationAttribute = ODBC32.SQL_ATTR.TXN_ISOLATION; 
                    break; 
                case IsolationLevel.RepeatableRead:
                    sql_iso = ODBC32.SQL_TRANSACTION.REPEATABLE_READ; 
                    isolationAttribute = ODBC32.SQL_ATTR.TXN_ISOLATION;
                    break;
                case IsolationLevel.Serializable:
                    sql_iso = ODBC32.SQL_TRANSACTION.SERIALIZABLE; 
                    isolationAttribute = ODBC32.SQL_ATTR.TXN_ISOLATION;
                    break; 
                case IsolationLevel.Snapshot: 
                    sql_iso = ODBC32.SQL_TRANSACTION.SNAPSHOT;
                    // VSDD 414121: Snapshot isolation level must be set through SQL_COPT_SS_TXN_ISOLATION (http://msdn.microsoft.com/en-us/library/ms131709.aspx) 
                    isolationAttribute = ODBC32.SQL_ATTR.SQL_COPT_SS_TXN_ISOLATION;
                    break;
                case IsolationLevel.Chaos:
                    throw ODBC.NotSupportedIsolationLevel(isolevel); 
                default:
                    throw ADP.InvalidIsolationLevel(isolevel); 
                } 

                //Set the isolation level (unless its unspecified) 
                retcode = SetConnectionAttribute2(isolationAttribute, (IntPtr)sql_iso, (Int32)ODBC32.SQL_IS.INTEGER);

                //Note: The Driver can return success_with_info to indicate it "rolled" the
                //isolevel to the next higher value.  If this is the case, we need to requery 
                //the value if th euser asks for it...
                //We also still propagate the info, since it could be other info as well... 
 
                if(ODBC32.RetCode.SUCCESS_WITH_INFO == retcode) {
                    isolevel = IsolationLevel.Unspecified; 
                }
            }

            switch(retcode) { 
            case ODBC32.RetCode.SUCCESS:
            case ODBC32.RetCode.SUCCESS_WITH_INFO: 
                //Turn off auto-commit (which basically starts the transaction) 
                retcode = AutoCommitOff();
                _handleState = HandleState.TransactionInProgress; 
                break;
            }
            return retcode;
        } 

        internal ODBC32.RetCode CompleteTransaction(short transactionOperation) { 
            bool mustRelease = false; 
            RuntimeHelpers.PrepareConstrainedRegions();
            try { 
                DangerousAddRef(ref mustRelease);
                ODBC32.RetCode retcode = CompleteTransaction(transactionOperation, base.handle);
                return retcode;
            } 
            finally {
                if (mustRelease) { 
                    DangerousRelease(); 
                }
            } 
        }

        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
        private ODBC32.RetCode CompleteTransaction(short transactionOperation, IntPtr handle) { 
            // must only call this code from ReleaseHandle or DangerousAddRef region
 
            ODBC32.RetCode retcode = ODBC32.RetCode.SUCCESS; 

            // using ConstrainedRegions to make the native ODBC call and change the _handleState 
            RuntimeHelpers.PrepareConstrainedRegions();
            try { } finally {
                if (HandleState.TransactionInProgress == _handleState) {
                    retcode = UnsafeNativeMethods.SQLEndTran(HandleType, handle, transactionOperation); 
                    if((ODBC32.RetCode.SUCCESS == retcode) || (ODBC32.RetCode.SUCCESS_WITH_INFO == retcode)) {
                        _handleState = HandleState.Transacted; 
                    } 
                    Bid.TraceSqlReturn(" %08X{SQLRETURN}\n", retcode);
                } 

                if (HandleState.Transacted == _handleState) { // AutoCommitOn
                    retcode = UnsafeNativeMethods.SQLSetConnectAttrW(handle, ODBC32.SQL_ATTR.AUTOCOMMIT, ODBC32.SQL_AUTOCOMMIT_ON, (Int32)ODBC32.SQL_IS.UINTEGER);
                    _handleState = HandleState.Connected; 
                    Bid.TraceSqlReturn(" %08X{SQLRETURN}\n", retcode);
                } 
            } 
            //Overactive assert which fires if handle was allocated - but failed to connect to the server
            //it can more legitmately fire if transaction failed to rollback - but there isn't much we can do in that situation 
            //Debug.Assert((HandleState.Connected == _handleState) || (HandleState.TransactionInProgress == _handleState), "not expected HandleState.Connected");
            return retcode;
        }
        private ODBC32.RetCode Connect(string connectionString) { 
            Debug.Assert(HandleState.Allocated == _handleState, "SQLDriverConnect while in wrong state?");
 
            ODBC32.RetCode retcode; 

            // Avoid runtime injected errors in the following block. 
            RuntimeHelpers.PrepareConstrainedRegions();
            try {} finally {

                short cbActualSize; 
                retcode = UnsafeNativeMethods.SQLDriverConnectW(this, ADP.PtrZero, connectionString, ODBC32.SQL_NTS, ADP.PtrZero, 0, out cbActualSize, (short)ODBC32.SQL_DRIVER.NOPROMPT);
                switch(retcode) { 
                case ODBC32.RetCode.SUCCESS: 
                case ODBC32.RetCode.SUCCESS_WITH_INFO:
                    _handleState = HandleState.Connected; 
                    break;
                }
            }
            ODBC.TraceODBC(3, "SQLDriverConnectW", retcode); 
            return retcode;
        } 
 
        override protected bool ReleaseHandle() {
            // NOTE: The SafeHandle class guarantees this will be called exactly once and is non-interrutible. 
            ODBC32.RetCode retcode;

            // must call complete the transaction rollback, change handle state, and disconnect the connection
            retcode = CompleteTransaction(ODBC32.SQL_ROLLBACK, handle); 

            if ((HandleState.Connected == _handleState) || (HandleState.TransactionInProgress == _handleState)) { 
                retcode = UnsafeNativeMethods.SQLDisconnect(handle); 
                _handleState = HandleState.Allocated;
                Bid.TraceSqlReturn(" %08X{SQLRETURN}\n", retcode); 
            }
            Debug.Assert(HandleState.Allocated == _handleState, "not expected HandleState.Allocated");
            return base.ReleaseHandle();
        } 

        internal ODBC32.RetCode GetConnectionAttribute(ODBC32.SQL_ATTR attribute, byte[] buffer, out int cbActual) { 
            ODBC32.RetCode retcode = UnsafeNativeMethods.SQLGetConnectAttrW(this, attribute, buffer, buffer.Length, out cbActual); 
            Bid.Trace(" SQLRETURN=%d, Attribute=%d, BufferLength=%d, StringLength=%d\n", (int)retcode, (int)attribute, buffer.Length, (int)cbActual);
            return retcode; 
        }

        internal ODBC32.RetCode GetFunctions(ODBC32.SQL_API fFunction, out Int16 fExists) {
            ODBC32.RetCode retcode = UnsafeNativeMethods.SQLGetFunctions(this, fFunction, out fExists); 
            ODBC.TraceODBC(3, "SQLGetFunctions", retcode);
            return retcode; 
        } 

        internal ODBC32.RetCode GetInfo2(ODBC32.SQL_INFO info, byte[] buffer, out short cbActual) { 
            ODBC32.RetCode retcode = UnsafeNativeMethods.SQLGetInfoW(this, info, buffer, checked((short)buffer.Length), out cbActual);
            Bid.Trace(" SQLRETURN=%d, InfoType=%d, BufferLength=%d, StringLength=%d\n", (int)retcode, (int)info, buffer.Length, (int)cbActual);
            return retcode;
        } 

        internal ODBC32.RetCode GetInfo1(ODBC32.SQL_INFO info, byte[] buffer) { 
            ODBC32.RetCode retcode = UnsafeNativeMethods.SQLGetInfoW(this, info, buffer, checked((short)buffer.Length), ADP.PtrZero); 
            Bid.Trace(" SQLRETURN=%d, InfoType=%d, BufferLength=%d\n", (int)retcode, (int)info, buffer.Length);
            return retcode; 
        }

        internal ODBC32.RetCode SetConnectionAttribute2(ODBC32.SQL_ATTR attribute, IntPtr value, Int32 length) {
            ODBC32.RetCode retcode = UnsafeNativeMethods.SQLSetConnectAttrW(this, attribute, value, length); 
            ODBC.TraceODBC(3, "SQLSetConnectAttrW", retcode);
            return retcode; 
        } 

        internal ODBC32.RetCode SetConnectionAttribute3(ODBC32.SQL_ATTR attribute, string buffer, Int32 length) { 
            ODBC32.RetCode retcode = UnsafeNativeMethods.SQLSetConnectAttrW(this, attribute, buffer, length);
            Bid.Trace(" SQLRETURN=%d, Attribute=%d, BufferLength=%d\n", (int)retcode, (int)attribute, buffer.Length);
            return retcode;
        } 

        internal ODBC32.RetCode SetConnectionAttribute4(ODBC32.SQL_ATTR attribute, System.Transactions.IDtcTransaction transaction, Int32 length) { 
            ODBC32.RetCode retcode = UnsafeNativeMethods.SQLSetConnectAttrW(this, attribute, transaction, length); 
            ODBC.TraceODBC(3, "SQLSetConnectAttrW", retcode);
            return retcode; 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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