/// <summary>
/// Wrap an object and return the transparent proxy which intercepts all calls to the object
/// </summary>
/// <param name="comObject">An object to intercept</param>
/// <param name="type">Interface which defines the method and properties to intercept</param>
/// <param name="targetName"></param>
/// <returns>Transparent proxy to the real proxy for the object</returns>
private static object Wrap(object comObject, Type type, string targetName)
{
if (null == comObject)
{
throw new ArgumentNullException(nameof(comObject));
}
if (null == type)
{
throw new ArgumentNullException(nameof(type));
}
var wrapper = new ComWrapper(comObject, type, targetName);
return(wrapper.GetTransparentProxy());
}
/// <summary>
/// Wrap a com object as COMWrapper
/// </summary>
/// <typeparam name="T">Interface which defines the method and properties to intercept</typeparam>
/// <param name="comObject">An object to intercept</param>
/// <returns>Transparent proxy to the real proxy for the object</returns>
public static T Wrap <T>(object comObject)
{
var type = typeof(T);
if (null == comObject)
{
throw new ArgumentNullException(nameof(comObject));
}
if (null == type)
{
throw new ArgumentNullException(nameof(T));
}
var wrapper = new ComWrapper(comObject, type, type.FullName);
return((T)wrapper.GetTransparentProxy());
}
/// <summary>
/// Intercept method calls
/// </summary>
/// <param name="myMessage">
/// Contains information about the method being called
/// </param>
/// <returns>
/// A <see cref="ReturnMessage" />.
/// </returns>
public override IMessage Invoke(IMessage myMessage)
{
var callMessage = myMessage as IMethodCallMessage;
if (null == callMessage)
{
Log.Debug().WriteLine("Message type not implemented: {0}", myMessage.GetType());
return(null);
}
var method = callMessage.MethodBase as MethodInfo;
if (null == method)
{
Log.Debug().WriteLine("Unrecognized Invoke call: {0}", callMessage.MethodBase);
return(null);
}
object returnValue = null;
object[] outArgs = null;
var outArgsCount = 0;
var methodName = method.Name;
var returnType = method.ReturnType;
var flags = BindingFlags.InvokeMethod;
var argCount = callMessage.ArgCount;
ParameterModifier[] argModifiers = null;
ParameterInfo[] parameters = null;
if ("Dispose" == methodName && 0 == argCount && typeof(void) == returnType)
{
Dispose();
}
else if ("ToString" == methodName && 0 == argCount && typeof(string) == returnType)
{
returnValue = ToString();
}
else if ("GetType" == methodName && 0 == argCount && typeof(Type) == returnType)
{
returnValue = _interceptType;
}
else if ("GetHashCode" == methodName && 0 == argCount && typeof(int) == returnType)
{
returnValue = GetHashCode();
}
else if ("Equals" == methodName && 1 == argCount && typeof(bool) == returnType)
{
returnValue = Equals(callMessage.Args[0]);
}
else if (1 == argCount && typeof(void) == returnType && (methodName.StartsWith("add_") || methodName.StartsWith("remove_")))
{
var removeHandler = methodName.StartsWith("remove_");
methodName = methodName.Substring(removeHandler ? 7 : 4);
// TODO: Something is missing here
var handler = callMessage.InArgs[0] as Delegate;
if (null == handler)
{
return(new ReturnMessage(new ArgumentNullException(nameof(handler)), callMessage));
}
}
else
{
var invokeObject = _comObject;
var invokeType = _comType;
object[] args;
ParameterInfo parameter;
if (methodName.StartsWith("get_"))
{
// Property Get
methodName = methodName.Substring(4);
flags = BindingFlags.GetProperty;
args = callMessage.InArgs;
}
else if (methodName.StartsWith("set_"))
{
// Property Set
methodName = methodName.Substring(4);
flags = BindingFlags.SetProperty;
args = callMessage.InArgs;
}
else
{
args = callMessage.Args;
if (null != args && 0 != args.Length)
{
// Modifiers for ref / out parameters
argModifiers = new ParameterModifier[1];
argModifiers[0] = new ParameterModifier(args.Length);
parameters = method.GetParameters();
for (var i = 0; i < parameters.Length; i++)
{
parameter = parameters[i];
if (parameter.IsOut || parameter.ParameterType.IsByRef)
{
argModifiers[0][i] = true;
outArgsCount++;
}
}
if (0 == outArgsCount)
{
argModifiers = null;
}
}
}
// Un-wrap wrapped COM objects before passing to the method
Type byValType;
ComWrapper wrapper;
ComWrapper[] originalArgs;
if (null == args || 0 == args.Length)
{
originalArgs = null;
}
else
{
originalArgs = new ComWrapper[args.Length];
for (var i = 0; i < args.Length; i++)
{
if (null != args[i] && RemotingServices.IsTransparentProxy(args[i]))
{
wrapper = RemotingServices.GetRealProxy(args[i]) as ComWrapper;
if (null != wrapper)
{
originalArgs[i] = wrapper;
args[i] = wrapper._comObject;
}
}
else if (0 != outArgsCount && argModifiers[0][i])
{
byValType = GetByValType(parameters[i].ParameterType);
if (byValType.IsInterface)
{
// If we're passing a COM object by reference, and
// the parameter is null, we need to pass a
// DispatchWrapper to avoid a type mismatch exception.
if (null == args[i])
{
args[i] = new DispatchWrapper(null);
}
}
else if (typeof(decimal) == byValType)
{
// If we're passing a decimal value by reference,
// we need to pass a CurrencyWrapper to avoid a
// type mismatch exception.
// http://support.microsoft.com/?kbid=837378
args[i] = new CurrencyWrapper(args[i]);
}
}
}
}
do
{
try
{
returnValue = invokeType.InvokeMember(methodName, flags, null, invokeObject, args, argModifiers, null, null);
break;
}
catch (InvalidComObjectException icoEx)
{
// Should assist BUG-1616 and others
Log.Warn().WriteLine(
"COM object {0} has been separated from its underlying RCW cannot be used. The COM object was released while it was still in use on another thread.",
_interceptType.FullName);
return(new ReturnMessage(icoEx, callMessage));
}
catch (Exception ex)
{
// Test for rejected
var comEx = ex as COMException ?? ex.InnerException as COMException;
if (comEx != null && (comEx.ErrorCode == RPC_E_CALL_REJECTED || comEx.ErrorCode == RPC_E_FAIL))
{
var destinationName = _targetName;
// Try to find a "catchy" name for the rejecting application
if (destinationName != null && destinationName.Contains("."))
{
destinationName = destinationName.Substring(0, destinationName.IndexOf(".", StringComparison.Ordinal));
}
if (destinationName == null)
{
destinationName = _interceptType.FullName;
}
// TODO: Log destinationName and rejected information
Log.Error().WriteLine("Error while creating {0}: {1}", destinationName, comEx.ErrorCode);
}
// Not rejected OR pressed cancel
return(new ReturnMessage(ex, callMessage));
}
} while (true);
// Handle enum and interface return types
if (null != returnValue)
{
if (returnType.IsInterface)
{
// Wrap the returned value in an intercepting COM wrapper
if (Marshal.IsComObject(returnValue))
{
returnValue = Wrap(returnValue, returnType, _targetName);
}
}
else if (returnType.IsEnum)
{
// Convert to proper Enum type
returnValue = Enum.Parse(returnType, returnValue.ToString());
}
}
// Handle out args
if (0 != outArgsCount)
{
outArgs = new object[args.Length];
for (var i = 0; i < parameters.Length; i++)
{
if (!argModifiers[0][i])
{
continue;
}
var arg = args[i];
if (null == arg)
{
continue;
}
parameter = parameters[i];
wrapper = null;
byValType = GetByValType(parameter.ParameterType);
if (typeof(decimal) == byValType)
{
var currencyWrapper = arg as CurrencyWrapper;
if (currencyWrapper != null)
{
arg = currencyWrapper.WrappedObject;
}
}
else if (byValType.IsEnum)
{
arg = Enum.Parse(byValType, arg.ToString());
}
else if (byValType.IsInterface && Marshal.IsComObject(arg))
{
wrapper = originalArgs[i];
if (null != wrapper && wrapper._comObject != arg)
{
wrapper.Dispose();
wrapper = null;
}
if (null == wrapper)
{
wrapper = new ComWrapper(arg, byValType, _targetName);
}
arg = wrapper.GetTransparentProxy();
}
outArgs[i] = arg;
}
}
}
return(new ReturnMessage(returnValue, outArgs, outArgsCount, callMessage.LogicalCallContext, callMessage));
}
/// <summary>
/// Gets or creates a COM object and returns the transparent proxy which intercepts all calls to the object
/// The ComProgId can be a normal ComProgId or a GUID prefixed with "clsid:"
/// </summary>
/// <typeparam name="T">Interface which defines the method and properties to intercept</typeparam>
/// <returns>Transparent proxy to the real proxy for the object</returns>
/// <remarks>T must be an interface decorated with the <see cref="ComProgIdAttribute" />attribute.</remarks>
public static T GetOrCreateInstance <T>()
{
var type = typeof(T);
if (null == type)
{
throw new ArgumentNullException(nameof(T));
}
if (!type.IsInterface)
{
throw new ArgumentException("The specified type must be an interface.", nameof(T));
}
var progIdAttribute = ComProgIdAttribute.GetAttribute(type);
if (string.IsNullOrEmpty(progIdAttribute?.Value))
{
throw new ArgumentException("The specified type must define a ComProgId attribute.", nameof(T));
}
object comObject = null;
Type comType = null;
var progId = progIdAttribute.Value;
var guid = Guid.Empty;
// Convert from clsid to Prog ID, if needed
if (progId.StartsWith("clsid:"))
{
guid = new Guid(progId.Substring(6));
var result = ProgIDFromCLSID(ref guid, out progId);
if (result != 0)
{
// Restore progId, as it's overwritten
progId = progIdAttribute.Value;
try
{
GetActiveObject(ref guid, IntPtr.Zero, out comObject);
}
catch (Exception)
{
Log.Warn().WriteLine("Error {0} getting instance for class id {1}", result, progIdAttribute.Value);
}
if (comObject == null)
{
Log.Warn().WriteLine("Error {0} getting progId {1}", result, progIdAttribute.Value);
}
}
else
{
Log.Info().WriteLine("Mapped {0} to progId {1}", progIdAttribute.Value, progId);
}
}
if (comObject == null && !progId.StartsWith("clsid:"))
{
try
{
comObject = Marshal.GetActiveObject(progId);
}
catch (COMException comE)
{
if (comE.ErrorCode == MK_E_UNAVAILABLE)
{
Log.Debug().WriteLine("No current instance of {0} object available.", progId);
}
else if (comE.ErrorCode == CO_E_CLASSSTRING)
{
Log.Warn().WriteLine("Unknown progId {0} (application not installed)", progId);
return(default(T));
}
else
{
Log.Warn().WriteLine(comE, "Error getting active object for " + progId);
}
}
catch (Exception e)
{
Log.Warn().WriteLine(e, "Error getting active object for " + progId);
}
}
// Did we get the current instance? If not, try to create a new
if (comObject == null)
{
try
{
comType = Type.GetTypeFromProgID(progId, true);
}
catch (Exception ex)
{
if (Guid.Empty != guid)
{
comType = Type.GetTypeFromCLSID(guid);
}
else
{
Log.Warn().WriteLine(ex, "Error type for " + progId);
}
}
if (comType != null)
{
try
{
comObject = Activator.CreateInstance(comType);
if (comObject != null)
{
Log.Debug().WriteLine("Created new instance of {0} object.", progId);
}
}
catch (Exception e)
{
Log.Warn().WriteLine(e, "Error creating object for " + progId);
}
}
}
if (comObject != null)
{
if (comObject is IDispatch)
{
var wrapper = new ComWrapper(comObject, type, progIdAttribute.Value);
return((T)wrapper.GetTransparentProxy());
}
return((T)comObject);
}
return(default(T));
}
