private static MethodInfo GetMatchingMethodInfo(DetourMethodAttribute sourceAttribute, MethodInfo destinationInfo)
{
// we should only ever get here in case the attribute was not defined with a sourceMethodInfo, but let's check just in case.
if (sourceAttribute.WasSetByMethodInfo)
{
return(sourceAttribute.sourceMethodInfo);
}
// aight, let's search by name
MethodInfo[] candidates =
sourceAttribute.sourceType.GetMethods(AllBindingFlags)
.Where(mi => mi.Name == sourceAttribute.sourceMethodName).ToArray();
// if we only get one result, we've got our method info - if the length is zero, the method doesn't exist.
if (candidates.Length == 0)
{
return(null);
}
if (candidates.Length == 1)
{
return(candidates.First());
}
// this is where things get slightly complicated, we'll have to search by parameters.
var destinationParameterTypes = destinationInfo.GetParameters().Select(pi => pi.ParameterType).ToList();
var extensionMethodType = GetExtensionMethodType(destinationInfo);
if (extensionMethodType != null)
{
// the "this" parameter should not be used in the parameter sequence comparison
destinationParameterTypes.RemoveAt(0);
}
candidates = candidates.Where(mi =>
mi.ReturnType == destinationInfo.ReturnType &&
(extensionMethodType == null || mi.DeclaringType == extensionMethodType) &&
mi.GetParameters().Select(pi => pi.ParameterType).SequenceEqual(destinationParameterTypes)).ToArray();
// if we only get one result, we've got our method info - if the length is zero, the method doesn't exist.
if (candidates.Length == 0)
{
return(null);
}
if (candidates.Length == 1)
{
return(candidates.First());
}
// if we haven't returned anything by this point there were still multiple candidates. This is theoretically impossible,
// unless I missed something.
return(null);
}
// get source and destination MethodInfo-s from DetourMethodAttribute
private static DetourPair GetDetourPairFromAttribute(DetourMethodAttribute sourceAttribute, MethodInfo destinationInfo)
{
// we need to get the method info of the source (usually, vanilla) method.
// if it was specified in the attribute, this is easy. Otherwise, we'll have to do some digging.
var sourceInfo = sourceAttribute.WasSetByMethodInfo
? sourceAttribute.sourceMethodInfo
: GetMatchingMethodInfo(sourceAttribute, destinationInfo);
// make sure we've got what we wanted.
if (sourceInfo == null)
{
throw new NullReferenceException("sourceMethodInfo could not be found based on attribute");
}
if (destinationInfo == null)
{
throw new ArgumentNullException("destinationInfo");
}
return(new DetourPair(sourceInfo, destinationInfo));
}
