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//------------------------------------------------------------------------------
// <copyright file="OdbcHandle.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
// <owner current="true" primary="false">Microsoft</owner>
//------------------------------------------------------------------------------
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 {
internal abstract class OdbcHandle : SafeHandle {
private ODBC32.SQL_HANDLE _handleType;
private OdbcHandle _parentHandle;
protected OdbcHandle(ODBC32.SQL_HANDLE handleType, OdbcHandle parentHandle) : base(IntPtr.Zero, true) {
_handleType = handleType;
bool mustRelease = false;
ODBC32.RetCode retcode = ODBC32.RetCode.SUCCESS;
// using ConstrainedRegions to make the native ODBC call and AddRef the parent
RuntimeHelpers.PrepareConstrainedRegions();
try {
// validate handleType
switch(handleType) {
case ODBC32.SQL_HANDLE.ENV:
Debug.Assert(null == parentHandle, "did not expect a parent handle");
retcode = UnsafeNativeMethods.SQLAllocHandle(handleType, IntPtr.Zero, out base.handle);
break;
case ODBC32.SQL_HANDLE.DBC:
case ODBC32.SQL_HANDLE.STMT:
// must addref before calling native so it won't be released just after
Debug.Assert(null != parentHandle, "expected a parent handle"); // safehandle can't be null
parentHandle.DangerousAddRef(ref mustRelease);
retcode = UnsafeNativeMethods.SQLAllocHandle(handleType, parentHandle, out base.handle);
break;
// case ODBC32.SQL_HANDLE.DESC:
default:
Debug.Assert(false, "unexpected handleType");
break;
}
}
finally {
if (mustRelease) {
switch(handleType) {
case ODBC32.SQL_HANDLE.DBC:
case ODBC32.SQL_HANDLE.STMT:
if (IntPtr.Zero != base.handle) {
// must assign _parentHandle after a handle is actually created
// since ReleaseHandle will only call DangerousRelease if a handle exists
_parentHandle = parentHandle;
}
else {
// without a handle, ReleaseHandle may not be called
parentHandle.DangerousRelease();
}
break;
}
}
}
Bid.TraceSqlReturn("<odbc.SQLAllocHandle|API|ODBC|RET> %08X{SQLRETURN}\n", retcode);
if((ADP.PtrZero == base.handle) || (ODBC32.RetCode.SUCCESS != retcode)) {
//
throw ODBC.CantAllocateEnvironmentHandle(retcode);
}
}
internal OdbcHandle(OdbcStatementHandle parentHandle, ODBC32.SQL_ATTR attribute) : base(IntPtr.Zero, true) {
Debug.Assert((ODBC32.SQL_ATTR.APP_PARAM_DESC == attribute) || (ODBC32.SQL_ATTR.APP_ROW_DESC == attribute), "invalid attribute");
_handleType = ODBC32.SQL_HANDLE.DESC;
int cbActual;
ODBC32.RetCode retcode;
bool mustRelease = false;
RuntimeHelpers.PrepareConstrainedRegions();
try {
// must addref before calling native so it won't be released just after
parentHandle.DangerousAddRef(ref mustRelease);
retcode = parentHandle.GetStatementAttribute(attribute, out base.handle, out cbActual);
}
finally {
if (mustRelease) {
if (IntPtr.Zero != base.handle) {
// must call DangerousAddRef after a handle is actually created
// since ReleaseHandle will only call DangerousRelease if a handle exists
_parentHandle = parentHandle;
}
else {
// without a handle, ReleaseHandle may not be called
parentHandle.DangerousRelease();
}
}
}
if (ADP.PtrZero == base.handle) {
throw ODBC.FailedToGetDescriptorHandle(retcode);
}
// no info-message handle on getting a descriptor handle
}
internal ODBC32.SQL_HANDLE HandleType {
get {
return _handleType;
}
}
public override bool IsInvalid {
get {
// we should not have a parent if we do not have a handle
return (IntPtr.Zero == base.handle);
}
}
override protected bool ReleaseHandle() {
// NOTE: The SafeHandle class guarantees this will be called exactly once and is non-interrutible.
IntPtr handle = base.handle;
base.handle = IntPtr.Zero;
if (IntPtr.Zero != handle) {
ODBC32.SQL_HANDLE handleType = HandleType;
switch (handleType) {
case ODBC32.SQL_HANDLE.DBC:
// Disconnect happens in OdbcConnectionHandle.ReleaseHandle
case ODBC32.SQL_HANDLE.ENV:
case ODBC32.SQL_HANDLE.STMT:
ODBC32.RetCode retcode = UnsafeNativeMethods.SQLFreeHandle(handleType, handle);
Bid.TraceSqlReturn("<odbc.SQLFreeHandle|API|ODBC|RET> %08X{SQLRETURN}\n", retcode);
break;
case ODBC32.SQL_HANDLE.DESC:
// nothing to free on the handle
break;
// case 0: ThreadAbortException setting handle before HandleType
default:
Debug.Assert(ADP.PtrZero == handle, "unknown handle type");
break;
}
}
// If we ended up getting released, then we have to release
// our reference on our parent.
OdbcHandle parentHandle = _parentHandle;
_parentHandle = null;
if (null != parentHandle) {
parentHandle.DangerousRelease();
parentHandle = null;
}
return true;
}
internal ODBC32.RetCode GetDiagnosticField (out string sqlState) {
short cbActual;
// ODBC (MSDN) documents it expects a buffer large enough to hold 5(+L'\0') unicode characters
StringBuilder sb = new StringBuilder(6);
ODBC32.RetCode retcode = UnsafeNativeMethods.SQLGetDiagFieldW(
HandleType,
this,
(short)1,
ODBC32.SQL_DIAG_SQLSTATE,
sb,
checked((short)(2*sb.Capacity)), // expects number of bytes, see \\kbinternal\kb\articles\294\1\69.HTM
out cbActual);
ODBC.TraceODBC(3, "SQLGetDiagFieldW", retcode);
if ((retcode == ODBC32.RetCode.SUCCESS) || (retcode == ODBC32.RetCode.SUCCESS_WITH_INFO)) {
sqlState = sb.ToString();
}
else {
sqlState = ADP.StrEmpty;
}
return retcode;
}
internal ODBC32.RetCode GetDiagnosticRecord(short record, out string sqlState, StringBuilder message, out int nativeError, out short cchActual) {
// ODBC (MSDN) documents it expects a buffer large enough to hold 4(+L'\0') unicode characters
StringBuilder sb = new StringBuilder(5);
ODBC32.RetCode retcode = UnsafeNativeMethods.SQLGetDiagRecW(HandleType, this, record, sb, out nativeError, message, checked((short)message.Capacity), out cchActual);
ODBC.TraceODBC(3, "SQLGetDiagRecW", retcode);
if ((retcode == ODBC32.RetCode.SUCCESS) || (retcode == ODBC32.RetCode.SUCCESS_WITH_INFO)) {
sqlState = sb.ToString();
}
else {
sqlState = ADP.StrEmpty;
}
return retcode;
}
}
sealed internal class OdbcDescriptorHandle : OdbcHandle {
internal OdbcDescriptorHandle(OdbcStatementHandle statementHandle, ODBC32.SQL_ATTR attribute) : base(statementHandle, attribute) {
}
internal ODBC32.RetCode GetDescriptionField(int i, ODBC32.SQL_DESC attribute, CNativeBuffer buffer, out int numericAttribute) {
ODBC32.RetCode retcode = UnsafeNativeMethods.SQLGetDescFieldW(this, checked((short)i), attribute, buffer, buffer.ShortLength, out numericAttribute);
ODBC.TraceODBC(3, "SQLGetDescFieldW", retcode);
return retcode;
}
internal ODBC32.RetCode SetDescriptionField1(short ordinal, ODBC32.SQL_DESC type, IntPtr value) {
ODBC32.RetCode retcode = UnsafeNativeMethods.SQLSetDescFieldW(this, ordinal, type, value, 0);
ODBC.TraceODBC(3, "SQLSetDescFieldW", retcode);
return retcode;
}
internal ODBC32.RetCode SetDescriptionField2(short ordinal, ODBC32.SQL_DESC type, HandleRef value) {
ODBC32.RetCode retcode = UnsafeNativeMethods.SQLSetDescFieldW(this, ordinal, type, value, 0);
ODBC.TraceODBC(3, "SQLSetDescFieldW", retcode);
return retcode;
}
}
}
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