private static PInvokeMap GetLinkFlags(NativeMethodAttributeBase nativeMethodAttr)
{
PInvokeMap linkFlags = 0;
if (nativeMethodAttr.ExactSpelling)
{
linkFlags |= PInvokeMap.NoMangle;
}
switch (nativeMethodAttr.CallingConvention)
{
case CallingConvention.Winapi:
linkFlags |= PInvokeMap.CallConvWinapi;
break;
case CallingConvention.Cdecl:
linkFlags |= PInvokeMap.CallConvCdecl;
break;
case CallingConvention.StdCall:
linkFlags |= PInvokeMap.CallConvStdcall;
break;
case CallingConvention.ThisCall:
linkFlags |= PInvokeMap.CallConvThiscall;
break;
case CallingConvention.FastCall:
linkFlags |= PInvokeMap.CallConvFastcall;
break;
}
switch (nativeMethodAttr.CharSet)
{
case CharSet.None:
linkFlags |= PInvokeMap.CharSetNotSpec;
break;
case CharSet.Ansi:
linkFlags |= PInvokeMap.CharSetAnsi;
break;
case CharSet.Unicode:
linkFlags |= PInvokeMap.CharSetUnicode;
break;
case CharSet.Auto:
linkFlags |= PInvokeMap.CharSetAuto;
break;
}
return(linkFlags);
}
private static MethodBuilder GeneratePInvokeMethod(TypeBuilder typeBuilder, string dllName, MethodInfo setPInvokeDataMethod, object runtimeModule, MethodInfo setTokenMethod, MethodInfo method, NativeMethodAttributeBase nativeMethodAttr, ParameterInfo[] methodParams, Type[] parameterTypes)
{
MethodBuilder pInvokeMethodBuilder = typeBuilder.DefineMethod(
"PIvk_" + method.Name,
MethodAttributes.Public | MethodAttributes.Static | MethodAttributes.PinvokeImpl | MethodAttributes.HideBySig,
CallingConventions.Standard,
method.ReturnType,
parameterTypes);
// Set PInvokeData.
var entryName = nativeMethodAttr.EntryPoint ?? method.Name;
var token = pInvokeMethodBuilder.GetToken();
PInvokeMap linkFlags = GetLinkFlags(nativeMethodAttr);
setPInvokeDataMethod.Invoke(null, new object[] { runtimeModule, dllName, entryName, token.Token, (int)linkFlags });
setTokenMethod.Invoke(pInvokeMethodBuilder, new object[] { token });
// Add PreserveSig to the method implementation flags.
// NOTE: If this line is commented out, the return value will be zero when the method is invoked.
pInvokeMethodBuilder.SetImplementationFlags(pInvokeMethodBuilder.GetMethodImplementationFlags() | MethodImplAttributes.PreserveSig);
var returnParameter = pInvokeMethodBuilder.DefineParameter(0, method.ReturnParameter.Attributes, null);
var returnParameterAttrs = CustomAttributeData.GetCustomAttributes(method.ReturnParameter);
foreach (var attr in returnParameterAttrs)
{
returnParameter.SetCustomAttribute(CreateAttributeBuilder(attr));
}
for (int i = 0; i < methodParams.Length; i++)
{
var p = methodParams[i];
var paramBuilder = pInvokeMethodBuilder.DefineParameter(i + 1, p.Attributes, p.Name);
foreach (var paramAttr in CustomAttributeData.GetCustomAttributes(p))
{
paramBuilder.SetCustomAttribute(CreateAttributeBuilder(paramAttr));
}
}
// The PInvoke method does not have a method body.
return(pInvokeMethodBuilder);
}