internal OleDbHResult InitializeAndCreateSession(OleDbConnectionString constr, ref SessionWrapper sessionWrapper)
{
OleDbHResult hr;
bool mustRelease = false;
IntPtr idbCreateSession = IntPtr.Zero;
RuntimeHelpers.PrepareConstrainedRegions();
try {
DangerousAddRef(ref mustRelease);
// native COM rules are the QI result is the 'this' pointer
// the pointer stored at that location is the vtable
// since IUnknown is a public,shipped COM interface, its layout will not change (ever)
IntPtr vtable = Marshal.ReadIntPtr(base.handle, 0);
IntPtr method = Marshal.ReadIntPtr(vtable, 0);
// we cache the QueryInterface delegate to prevent recreating it on every call
UnsafeNativeMethods.IUnknownQueryInterface QueryInterface = constr.DangerousDataSourceIUnknownQueryInterface;
// since the delegate lifetime is longer than the original instance used to create it
// we double check before each usage to verify the delegates function pointer
if ((null == QueryInterface) || (method != Marshal.GetFunctionPointerForDelegate(QueryInterface)))
{
QueryInterface = (UnsafeNativeMethods.IUnknownQueryInterface)Marshal.GetDelegateForFunctionPointer(method, typeof(UnsafeNativeMethods.IUnknownQueryInterface));
constr.DangerousDataSourceIUnknownQueryInterface = QueryInterface;
}
// native COM rules are the QI result is the 'this' pointer
// the pointer stored at that location is the vtable
// since IDBInitialize is a public,shipped COM interface, its layout will not change (ever)
vtable = Marshal.ReadIntPtr(base.handle, 0);
method = Marshal.ReadIntPtr(vtable, 3 * IntPtr.Size); // Initialize is the 4'th vtable entry
// we cache the Initialize delegate to prevent recreating it on every call
UnsafeNativeMethods.IDBInitializeInitialize Initialize = constr.DangerousIDBInitializeInitialize;
// since the delegate lifetime is longer than the original instance used to create it
// we double check before each usage to verify the delegates function pointer
if ((null == Initialize) || (method != Marshal.GetFunctionPointerForDelegate(Initialize)))
{
Initialize = (UnsafeNativeMethods.IDBInitializeInitialize)Marshal.GetDelegateForFunctionPointer(method, typeof(UnsafeNativeMethods.IDBInitializeInitialize));
constr.DangerousIDBInitializeInitialize = Initialize;
}
// call IDBInitialize::Initialize via the delegate
hr = Initialize(base.handle);
// we don't ever expect DB_E_ALREADYINITIALIZED, but since we checked in V1.0 - its propagated along
if ((0 <= hr) || (OleDbHResult.DB_E_ALREADYINITIALIZED == hr))
{
// call IUnknown::QueryInterface via the delegate
hr = (OleDbHResult)QueryInterface(base.handle, ref ODB.IID_IDBCreateSession, ref idbCreateSession);
if ((0 <= hr) && (IntPtr.Zero != idbCreateSession))
{
// native COM rules are the QI result is the 'this' pointer
// the pointer stored at that location is the vtable
// since IDBCreateSession is a public,shipped COM interface, its layout will not change (ever)
vtable = Marshal.ReadIntPtr(idbCreateSession, 0);
method = Marshal.ReadIntPtr(vtable, 3 * IntPtr.Size); // CreateSession is the 4'th vtable entry
UnsafeNativeMethods.IDBCreateSessionCreateSession CreateSession = constr.DangerousIDBCreateSessionCreateSession;
// since the delegate lifetime is longer than the original instance used to create it
// we double check before each usage to verify the delegates function pointer
if ((null == CreateSession) || (method != Marshal.GetFunctionPointerForDelegate(CreateSession)))
{
CreateSession = (UnsafeNativeMethods.IDBCreateSessionCreateSession)Marshal.GetDelegateForFunctionPointer(method, typeof(UnsafeNativeMethods.IDBCreateSessionCreateSession));
constr.DangerousIDBCreateSessionCreateSession = CreateSession;
}
// if I have a delegate for CreateCommand directly ask for IDBCreateCommand
if (null != constr.DangerousIDBCreateCommandCreateCommand)
{
// call IDBCreateSession::CreateSession via the delegate directly for IDBCreateCommand
hr = CreateSession(idbCreateSession, IntPtr.Zero, ref ODB.IID_IDBCreateCommand, ref sessionWrapper);
if ((0 <= hr) && !sessionWrapper.IsInvalid)
{
// double check the cached delegate is correct
sessionWrapper.VerifyIDBCreateCommand(constr);
}
}
else
{
// otherwise ask for IUnknown (it may be first time usage or IDBCreateCommand not supported)
hr = CreateSession(idbCreateSession, IntPtr.Zero, ref ODB.IID_IUnknown, ref sessionWrapper);
if ((0 <= hr) && !sessionWrapper.IsInvalid)
{
// and check support for IDBCreateCommand and create delegate for CreateCommand
sessionWrapper.QueryInterfaceIDBCreateCommand(constr);
}
}
}
}
}
finally {
if (IntPtr.Zero != idbCreateSession)
{
// release the QI for IDBCreateSession
Marshal.Release(idbCreateSession);
}
if (mustRelease)
{
// release the AddRef on DataLinks
DangerousRelease();
}
}
return(hr);
}
internal OleDbHResult InitializeAndCreateSession(OleDbConnectionString constr, ref SessionWrapper sessionWrapper)
{
OleDbHResult result;
bool success = false;
IntPtr zero = IntPtr.Zero;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
base.DangerousAddRef(ref success);
IntPtr ptr = Marshal.ReadIntPtr(Marshal.ReadIntPtr(base.handle, 0), 0);
UnsafeNativeMethods.IUnknownQueryInterface dangerousDataSourceIUnknownQueryInterface = constr.DangerousDataSourceIUnknownQueryInterface;
if ((dangerousDataSourceIUnknownQueryInterface == null) || (ptr != Marshal.GetFunctionPointerForDelegate(dangerousDataSourceIUnknownQueryInterface)))
{
dangerousDataSourceIUnknownQueryInterface = (UnsafeNativeMethods.IUnknownQueryInterface)Marshal.GetDelegateForFunctionPointer(ptr, typeof(UnsafeNativeMethods.IUnknownQueryInterface));
constr.DangerousDataSourceIUnknownQueryInterface = dangerousDataSourceIUnknownQueryInterface;
}
ptr = Marshal.ReadIntPtr(Marshal.ReadIntPtr(base.handle, 0), 3 * IntPtr.Size);
UnsafeNativeMethods.IDBInitializeInitialize dangerousIDBInitializeInitialize = constr.DangerousIDBInitializeInitialize;
if ((dangerousIDBInitializeInitialize == null) || (ptr != Marshal.GetFunctionPointerForDelegate(dangerousIDBInitializeInitialize)))
{
dangerousIDBInitializeInitialize = (UnsafeNativeMethods.IDBInitializeInitialize)Marshal.GetDelegateForFunctionPointer(ptr, typeof(UnsafeNativeMethods.IDBInitializeInitialize));
constr.DangerousIDBInitializeInitialize = dangerousIDBInitializeInitialize;
}
result = dangerousIDBInitializeInitialize(base.handle);
if ((OleDbHResult.S_OK > result) && (OleDbHResult.DB_E_ALREADYINITIALIZED != result))
{
return(result);
}
result = (OleDbHResult)dangerousDataSourceIUnknownQueryInterface(base.handle, ref ODB.IID_IDBCreateSession, ref zero);
if ((OleDbHResult.S_OK > result) || !(IntPtr.Zero != zero))
{
return(result);
}
ptr = Marshal.ReadIntPtr(Marshal.ReadIntPtr(zero, 0), 3 * IntPtr.Size);
UnsafeNativeMethods.IDBCreateSessionCreateSession dangerousIDBCreateSessionCreateSession = constr.DangerousIDBCreateSessionCreateSession;
if ((dangerousIDBCreateSessionCreateSession == null) || (ptr != Marshal.GetFunctionPointerForDelegate(dangerousIDBCreateSessionCreateSession)))
{
dangerousIDBCreateSessionCreateSession = (UnsafeNativeMethods.IDBCreateSessionCreateSession)Marshal.GetDelegateForFunctionPointer(ptr, typeof(UnsafeNativeMethods.IDBCreateSessionCreateSession));
constr.DangerousIDBCreateSessionCreateSession = dangerousIDBCreateSessionCreateSession;
}
if (constr.DangerousIDBCreateCommandCreateCommand != null)
{
result = dangerousIDBCreateSessionCreateSession(zero, IntPtr.Zero, ref ODB.IID_IDBCreateCommand, ref sessionWrapper);
if ((OleDbHResult.S_OK <= result) && !sessionWrapper.IsInvalid)
{
sessionWrapper.VerifyIDBCreateCommand(constr);
}
return(result);
}
result = dangerousIDBCreateSessionCreateSession(zero, IntPtr.Zero, ref ODB.IID_IUnknown, ref sessionWrapper);
if ((OleDbHResult.S_OK <= result) && !sessionWrapper.IsInvalid)
{
sessionWrapper.QueryInterfaceIDBCreateCommand(constr);
}
}
finally
{
if (IntPtr.Zero != zero)
{
Marshal.Release(zero);
}
if (success)
{
base.DangerousRelease();
}
}
return(result);
}
