public void ProcessParameters(Net2ObjC n2c, MethodFacet facet, Dictionary <string, object> options = null)
{
int idx = 0;
foreach (ParameterFacet parameter in facet.Parameters)
{
// Known issues:
//
// 1. Rendering of T[]& fails as in System.Array:Resize<T>(ref T[], int)
// <Parameter Name="array" Type="T[]&" ElementType="T[]" IsByRef="True" ContainsGenericParameters="True"/>
// Issue : T[]& renders as T**
// Workaround: exclude in config.objc.xml like so <string>System.Array:Resize</string>
// Suggested fix: provide a separate Element xml element to detail the ElementType more fully.
// if the mono parameters is passed by ref then strip
// the suffix to enable type association
string monoParameterType = parameter.Type;
if (parameter.IsByRef || parameter.IsPointer)
{
monoParameterType = parameter.ElementType;
}
//
// build the ObjC method interleaved parameter representation
// eg: name1:(int32_t)p1 name2:(int64_t)p2 name3:(NSString *)p3
//
string objCParamTypeDecl = null;
bool objCParameterIsObject = true;
//
// Get the ObjC type associated with the parameter.
//
ObjCTypeAssociation objCTypeAssociate = n2c.ObjCTypeAssociate(parameter);
ManagedTypeAssociation managedTypeAssociate = null;
if (objCTypeAssociate != null)
{
//
// If the parameter is an array, say Int64[], then its Obj-C rep will be System.Array
// The mono type association however must reflect the represented type, Int64.
//
if (parameter.IsArray)
{
ObjCTypeAssociation objCRepresentedTypeAssociate = n2c.ObjCTypeAssociate(parameter.ElementType);
if (objCRepresentedTypeAssociate != null)
{
managedTypeAssociate = objCRepresentedTypeAssociate.ManagedTypeAssociate;
}
}
if (managedTypeAssociate == null)
{
managedTypeAssociate = objCTypeAssociate.ManagedTypeAssociate;
}
objCParamTypeDecl = objCTypeAssociate.ObjCTypeDecl;
objCParameterIsObject = objCTypeAssociate.IsNSObject;
}
else
{
//
// Generate default objC representations
//
objCParamTypeDecl = n2c.ObjCTypeDeclFromManagedFacet(parameter);
objCParameterIsObject = n2c.ObjCRepresentationIsObject(parameter);
}
// if parameter is an interface then use adoption conforming type ie: id <typename>
if (parameter.IsInterface)
{
objCParamTypeDecl = n2c.ObjCConformingTypeFromObjCTypeDecl(objCParamTypeDecl, false);
}
if (parameter.IsByRef || parameter.IsPointer)
{
objCParamTypeDecl += "*"; // add additional indirection
}
//
// Build the mono method argument invocation signature
//
if (idx > 0)
{
MonoSigBuilder.Append(",");
}
string monoParameterTypeInvoke = null;
// if type is a GenericParameter defined by the class, as opposed to via a method like so Method<T>(T).
// in this case we want to identify the parameter by its position as this makes it simple
// to build the required signature at run time
if (parameter.IsGenericParameter && !parameter.DeclaredByMethod)
{
// generic parameters must have an associate
if (managedTypeAssociate == null)
{
throw new Exception("Missing managed type association for generic parameter.");
}
monoParameterTypeInvoke = managedTypeAssociate.ManagedTypeInvoke;
if (parameter.IsArray)
{
monoParameterTypeInvoke += "[]";
}
// in order for the C api to substitute the correct type at run time
// the generic parameter position needs to be indicated.
monoParameterTypeInvoke = string.Format(monoParameterTypeInvoke, parameter.GenericParameterPosition);
}
// if parameter is declared by the method like so Method<T>(T) then we want to preserve the type name
// as this constitutes part of the method signature this is used to lookup the generic method for inflation
else if (parameter.IsGenericParameter && parameter.DeclaredByMethod)
{
// we expect to be operating on a generic method definition
if (!facet.IsGenericMethodDefinition)
{
throw new Exception("Generic method definition expected.");
}
// the type sig will be something like Declaring.Type+T but the embedded API sig
// uses just the type parameter name T
int symbolIndex = monoParameterType.IndexOf('+');
if (symbolIndex == -1)
{
throw new Exception("Missing nested type symbol for generic parameter.");
}
monoParameterTypeInvoke = monoParameterType.Substring(symbolIndex + 1);
if (parameter.IsArray)
{
monoParameterTypeInvoke += "[]";
}
}
else
{
monoParameterTypeInvoke = n2c.ManagedTypeInvokeFromManagedType(monoParameterType);
}
// Note that we use a separate variable to hold the actual type sig used in the in mono_method_desc call
// as the signature may need to be specfically modified for the mono_method_desc API.
string monoParameterTypeInvoke_ = monoParameterTypeInvoke;
// The mono_method_desc * APIs prefix nested classes with a '/' rather than a '+' to conform with IL/CTS conventions
// The approach used here is trivial and is likely fragile.
// We probably need a separate mono param type builder like that found in debug-helpers.c append_class_name().
// Note that Delegates will present as nested classes.
// Also note that although we have an IsNested property we shouldn't use it as a conditional test for this operation
// as generic types with nested type paramaters such as System.Collections.Generic.IEnumerable`1<A.B+C>
// won't identify as nested.
monoParameterTypeInvoke_ = monoParameterTypeInvoke_.Replace("+", "/");
// add type signature and access modifier
MonoSigBuilder.Append(monoParameterTypeInvoke_);
if (parameter.IsPointer)
{
MonoSigBuilder.Append("*");
}
if (parameter.IsByRef)
{
MonoSigBuilder.Append("&"); // the signature needs to express by ref
}
// Build ObjC parameter name.
// In order to represent overloaded methods effectively the
// ObjC paramter name is constructed as follows:
// Managed parameter name + Managed parameter type + Ref
string objCParamName = ObjCIdentifierFromManagedIdentifier(parameter.Name);
// If the method is overloaded by parameter then make the ObjC method
// name unique by including type info in the name.
//
// Managed methods are overloaded by name only.
// The Obj-C metjods representation uses interleaved parameters which may
// be sufficient to produce a unique method signature.
//
// If however a managed method overload differs only in the type of its parameters
// (the managed method name, parameter count and parameter names all being equal)
// then the Obj-C interleaved parameters will include type info.
string objCParamOverloadSuffix = "";
if (facet.IsOverloadedParameterMethod)
{
// We adopt a minimal as opposed to a full type repesentation here in order
// to minimize the parameter length.
// Time will tell how it flies.
objCParamOverloadSuffix = n2c.ObjCMinimalIdentifierFromManagedIdentifier(monoParameterTypeInvoke);
if (parameter.IsArray)
{
objCParamOverloadSuffix += "Array";
}
if (parameter.IsPointer)
{
objCParamOverloadSuffix += "Ptr";
}
}
if (parameter.IsByRef)
{
objCParamOverloadSuffix += "Ref";
}
if (objCParamOverloadSuffix.Length > 0)
{
objCParamName += objCParamOverloadSuffix.FirstCharacterToUpper();
}
// append the complete interleaved parameter expression
if (idx == 0)
{
if (n2c.AppendFirstArgSignatureToMethodName)
{
// the leading underscore helps identify the preceding characters as the managed method name
ObjCMethodName += "_with";
ObjCParameterBuilder.AppendFormat("{0}", objCParamName.FirstCharacterToUpper());
}
}
else
{
ObjCParameterBuilder.AppendFormat(" {0}", objCParamName.FirstCharacterToLower());
}
// normalise the obj C parameter type for use as an invocation API parameter
string invokeApiObjCParamTypeDecl = n2c.NormaliseObjCTypeDecl(objCParamTypeDecl, ObjCTypeDeclNormalisation.InvokeApiParameterType);
ObjCParameterBuilder.AppendFormat(":({0})p{1}", invokeApiObjCParamTypeDecl, idx + 1);
//
// build the mono invocation argument representation
//
string argFormat = null;
if (idx > 0)
{
InvokeArgsBuilder.Append(", ");
}
if (objCParameterIsObject)
{
if (parameter.IsByRef)
{
// use reference pointer
argFormat = "&refPtr{0}";
}
else if (parameter.IsGenericParameter)
{
if (parameter.DeclaredByMethod)
{
argFormat = "[method monoRTInvokeArg:p{0}" + $" typeParameterIndex:{parameter.GenericParameterPosition}]";
}
else
{
argFormat = "[self monoRTInvokeArg:p{0}" + $" typeParameterIndex:{parameter.GenericParameterPosition}]";
}
}
else if (parameter.IsValueType)
{
// if parameter is of value type then get suitable embedded runtime API argument value.
// in general value types are passed as unboxed data.
argFormat = "[p{0} monoRTInvokeArg]";
}
else
{
// is parameter is of object type then get suitable embedded runtime API argument value.
// note that if the actual argument is of value type it will be passed as a boxed value.
argFormat = "[p{0} monoRTInvokeObject]";
}
}
else
{
if (parameter.IsByRef || parameter.IsPointer)
{
argFormat = "p{0}"; // just pass the pointer
}
else
{
argFormat = "&p{0}";
}
}
InvokeArgsBuilder.AppendFormat(argFormat, idx + 1);
//
// Build reference parameter pre and post process assignment statements
//
// Reference parameters need to be assigned to temporary variables
// to allow for their mutation
//
if (objCParameterIsObject && parameter.IsByRef)
{
// dereference and assign temporary variable
string preProcess = string.Format("void *refPtr{0} = [*p{0} monoRTInvokeArg];{1}", idx + 1, Environment.NewLine);
ReferencePreProcessBuilder.Append(preProcess);
// create new object subclass for reference
string postProcess = string.Format("*p{0} = [System_Object bestObjectWithMonoObject:refPtr{0}];{1}", idx + 1, Environment.NewLine);
ReferencePostProcessBuilder.Append(postProcess);
}
idx++;
}
}
