private void ProcessParameters(Net2ObjC n2c, EventFacet facet, Dictionary <string, object> options = null)
{
int idx = 0;
int idxMax = facet.Parameters.Count > 0 ? facet.Parameters.Count - 1 : 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);
}
ObjCEventBlockParameterGetters[idx] = objCTypeAssociate?.GetterFormat ?? string.Empty;
// 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());
}
ObjCParameterBuilder.AppendFormat(":({0})p{1}", objCParamTypeDecl, idx + 1);
// build C parameter list
string cParamDelim = idxMax > 0 && idx < idxMax ? ", " : "";
CParameterBuilder.AppendFormat($"{objCParamTypeDecl} {objCParamName.FirstCharacterToLower()}{cParamDelim}");
idx++;
}
}
public ObjCMethod(Net2ObjC n2c, MethodFacet facet, Dictionary <string, object> options = null)
{
// In order to ensure compilation of an assembly and its references
// the generated code must resolve all types.
//
// The generation of a complete set of methods is obviously desirable
// but in some cases may not be achievable if a unique method signature
// cannot be obtained.
// if the method is a duplicate (ie: name, parameter types, return type)
// then we have no option but to omit it
if (facet.IsDuplicateSignatureMethod)
{
n2c.Warning("Duplicate method omitted : " + facet.Name);
return;
}
// if the facet is overloaded on its signature and differs only in its
// return type then omit it.
// This can occur with explicit operators.
// At present it is unknown if these can be called via the embedded API.
if (facet.IsOverloadedSignatureMethod)
{
n2c.Warning("Overloaded signature method omitted : " + facet.Name);
return;
}
string objCMethodInvokeFormat = null;
string objCMethodPrepareFormat = null;
IsConstructorMethod = (facet.Name == null); // constructor has no method name
ObjCMethodType = null;
// Method name. We do some rudimentary processing to prevent troublesome behaviour.
// We may have to prefix certain method names to conform to ARC's semantics
// see https://stackoverflow.com/questions/22529454/simple-rules-for-naming-methods-compatible-with-arc-naming-conventions
MonoMethodName = facet.Name;
ObjCMethodName = MonoMethodName.FirstCharacterToLower();
if (facet.IsStatic || IsConstructorMethod)
{
ObjCMethodType = "+";
if (facet.Parameters.Count == 0)
{
// decorate class method names known to be unsafe
if (n2c.UnsafeObjCClassMethodNames.Contains(ObjCMethodName))
{
ObjCMethodName += "_";
}
}
}
else
{
ObjCMethodType = "-";
// decorate instance method names known to be unsafe
if (facet.Type != "System.Void" && n2c.UnsafeObjCMethodNames().Any(p => ObjCMethodName.StartsWith(p, false, null)))
{
ObjCMethodName = "db_" + ObjCMethodName;
}
}
// Get ObjC declaration for method return type.
// In general we want to allow the type association mechanism to substitute
// native objC types for managed types where appropriate.
// For example: a managed method that returns a System_DateTime results in an native method that returns an NSDate *.
// However, when defining a constructor we don't want to permit this association to occur as the constructor
// won't then contruct a managed instance at all.
ObjCTypeDecl = n2c.ObjCTypeDeclFromManagedFacet(facet, !IsConstructorMethod);
if (facet.IsInterface)
{
ObjCTypeDecl = n2c.ObjCConformingTypeFromObjCTypeDecl(ObjCTypeDecl, true);
}
ManagedValueToObjC = null;
// instance method requires a name and type
if (!IsConstructorMethod)
{
// create Obj-C representation of mono object
ManagedValueToObjC = n2c.ManagedValueToObjc(ManagedVariableName, facet);
// invocation statement
if (facet.IsGenericMethodDefinition)
{
// generic method definitions require additional type processing prior to invocation.
// DBManagedMethod co-ordinates this.
if (facet.IsStatic)
{
// invoke class method
objCMethodPrepareFormat = "DBManagedMethod *method = [self classMethodWithMonoName:\"{0}({1})\" typeParameters:typeParameter]";
objCMethodInvokeFormat = "[method invokeClassMethodWithNumArgs:{2}]";
}
else
{
objCMethodPrepareFormat = "DBManagedMethod *method = [self methodWithMonoName:\"{0}({1})\" typeParameters:typeParameter]";
objCMethodInvokeFormat = "[method invokeMethodWithNumArgs:{2}]";
}
}
else
{
if (facet.IsStatic)
{
// invoke mono class method
objCMethodInvokeFormat = "[self invokeMonoClassMethod:\"{0}({1})\" withNumArgs:{2}]";
}
else
{
// invoke mono instance method
objCMethodInvokeFormat = "[self invokeMonoMethod:\"{0}({1})\" withNumArgs:{2}]";
}
}
}
else
{
// this looks like a default constructor
if (facet.Parameters.Count() == 0)
{
return;
}
ObjCMethodName = "new";
// a constructor requires no explicit name or type
objCMethodInvokeFormat = "[[self alloc] initWithSignature:\"{1}\" withNumArgs:{2}]";
}
// process the parameters
ProcessParameters(n2c, facet, options);
// a generic method definition will require an additional parameter to specify the generic type parameters
if (facet.IsGenericMethodDefinition)
{
// get number of generic type parameters defined by the generic method definition as opposed to by the type defining the method
int numberOfTypeParametersDeclaredByMethod = facet.GenericMethodDefinitionGenericTypeArguments.Count();
string parameterSig = "typeParameter:(id)typeParameter";
if (numberOfTypeParametersDeclaredByMethod > 1)
{
parameterSig = "typeParameters:(NSArray<id> *)typeParameter";
}
if (facet.Parameters.Count() == 0)
{
ObjCMethodName += "_with";
ObjCParameterBuilder.AppendFormat("{0}", parameterSig.FirstCharacterToUpper());
}
else
{
ObjCParameterBuilder.AppendFormat(" {0}", parameterSig);
}
}
// finalize argument list representations
string monoMethodSig = MonoSigBuilder.ToString();
ObjCMethodParameters = ObjCParameterBuilder.ToString();
string invokeArgs = facet.Parameters.Count().ToString();
if (facet.Parameters.Count() > 0)
{
invokeArgs += ", " + InvokeArgsBuilder.ToString();
}
// form mono method invocation name.
// a prefix may be required, for instance when calling explicit interface methods.
string monoMethodPrefix = "";
if (options != null)
{
if (options.ContainsKey("cAPIMethodPrefix"))
{
monoMethodPrefix = (string)options["cAPIMethodPrefix"];
}
}
string monoInvocationName = monoMethodPrefix + MonoMethodName;
// we may have an expression that prepares the get expression method argument
if (objCMethodPrepareFormat != null)
{
string expression = String.Format(objCMethodPrepareFormat, monoInvocationName, monoMethodSig, invokeArgs) + ";";
ReferencePreProcessBuilder.AppendFormat("{0}{1}", expression, Environment.NewLine);
}
// the get expression invokes the method and gets the result
GetExpression = String.Format(objCMethodInvokeFormat, monoInvocationName, monoMethodSig, invokeArgs);
// validation
if (IsConstructorMethod && String.IsNullOrEmpty(monoMethodSig))
{
throw new Exception("Mono method argument signature is empty");
}
if (String.IsNullOrEmpty(ObjCTypeDecl))
{
throw new Exception("ObjC type Declaration is empty");
}
if (String.IsNullOrEmpty(ObjCMethodName))
{
throw new Exception("Method name is empty");
}
if (String.IsNullOrEmpty(GetExpression))
{
throw new Exception("Get expression is empty");
}
IsValid = true;
}