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Interop.cs
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Interop.cs
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using Microsoft.CodeAnalysis;
using System.Collections.Immutable;
using System.Security.Cryptography;
using System.Text;
namespace Reinterop
{
internal class Interop
{
/// <summary>
/// Creates a C# delegate, field of delegate type, and method/constructor/property to be invoked
/// by the delegate in order to provide a way for C++ code to call the method/constructor/property.
/// </summary>
/// <param name="compilation">The compilation context.</param>
/// <param name="ownerType">The type that owns the method, constructor, or property.</param>
/// <param name="method">The method, constructor, or property getter/setter.</param>
/// <param name="interopFunctionName">The name to use for the function, which must be unique within its containing type.</param>
/// <returns>The Name and Content to add to the C# GeneratedInit functions list.</returns>
public static (string Name, string Content) CreateCSharpDelegateInit(
CppGenerationContext context,
ITypeSymbol ownerType,
IMethodSymbol method,
string interopFunctionName)
{
CSharpType csType = CSharpType.FromSymbol(context, ownerType);
var parameters = method.Parameters;
var returnType = method.ReturnType;
IPropertySymbol? property = method.AssociatedSymbol as IPropertySymbol;
IEventSymbol? evt = method.AssociatedSymbol as IEventSymbol;
string accessName;
if (method.Name == ".ctor")
accessName = $"new {csType.GetFullyQualifiedName()}";
else if (property != null && property.IsIndexer)
accessName = "";
else if (property != null)
accessName = "." + property.Name;
else if (evt != null)
accessName = "." + evt.Name;
else
accessName = "." + method.Name;
if (method.IsGenericMethod)
{
accessName += $"<{string.Join(", ", method.TypeArguments.Select(t => t.ToDisplayString()))}>";
}
var callParameterDetails = parameters.Select(parameter => (Name: parameter.Name, Type: CSharpType.FromSymbol(context, parameter.Type), InteropType: CSharpType.FromSymbol(context, parameter.Type).AsInteropTypeParameter()));
var interopParameterDetails = callParameterDetails;
string invocationTarget;
string beforeInvocation = "";
string afterInvocation = "";
if (method.Name == ".ctor")
{
// New object construction
invocationTarget = $"new {csType.GetFullyQualifiedName()}";
returnType = ownerType;
}
else if (!method.IsStatic && csType.Kind == InteropTypeKind.NonBlittableStructWrapper)
{
// Structs must be unboxed, modified, and then reboxed.
interopParameterDetails = new[] { (Name: "thiz", Type: csType, InteropType: csType.AsInteropTypeParameter()) }.Concat(interopParameterDetails);
beforeInvocation = $"var thizUnboxed = {csType.GetParameterConversionFromInteropType("thiz")};";
invocationTarget = $"thizUnboxed{accessName}";
afterInvocation = $"Reinterop.ObjectHandleUtility.ResetHandleObject(thiz, thizUnboxed);";
}
else if (!method.IsStatic)
{
// Instance method or property
interopParameterDetails = new[] { (Name: "thiz", Type: csType, InteropType: csType.AsInteropTypeParameter()) }.Concat(interopParameterDetails);
invocationTarget = $"({csType.GetParameterConversionFromInteropType("thiz")}){accessName}";
}
else
{
// Static method or property
invocationTarget = $"{csType.GetFullyQualifiedName()}{accessName}";
}
CSharpType csReturnType = CSharpType.FromSymbol(context, returnType);
CSharpType csInteropReturnType = csReturnType.AsInteropTypeReturn();
// Rewrite methods that return a blittable struct to instead take a pointer to one.
// See Interop.RewriteStructReturn in this file for the C++ side of this and more
// explanation of why it's needed.
bool hasStructRewrite = false;
CSharpType csOriginalInteropReturnType = csInteropReturnType;
if (csReturnType.Kind == InteropTypeKind.BlittableStruct || csReturnType.Kind == InteropTypeKind.Nullable)
{
hasStructRewrite = true;
if (csReturnType.Kind == InteropTypeKind.Nullable)
csInteropReturnType = CSharpType.FromSymbol(context, context.Compilation.GetSpecialType(SpecialType.System_Byte));
else
csInteropReturnType = CSharpType.FromSymbol(context, context.Compilation.GetSpecialType(SpecialType.System_Void));
interopParameterDetails = interopParameterDetails.Concat(new[]
{
(Name: "pReturnValue", Type: csReturnType, InteropType: csOriginalInteropReturnType.AsPointer())
});
}
string interopReturnTypeString = csInteropReturnType.GetFullyQualifiedName();
string callParameterList = string.Join(", ", callParameterDetails.Select(parameter => parameter.Type.GetParameterConversionFromInteropType(parameter.Name)));
string interopParameterList = string.Join(", ", interopParameterDetails.Select(parameter => $"{parameter.InteropType.GetFullyQualifiedName()} {parameter.Name}"));
string implementation;
if (property != null && SymbolEqualityComparer.Default.Equals(property.GetMethod, method))
{
if (property.IsIndexer)
{
// An element indexer (operator[])
implementation =
$$"""
{{beforeInvocation}}
var result = {{invocationTarget}}[{{callParameterList}}];
{{afterInvocation}}
""";
}
else
{
// A property getter.
implementation =
$$"""
{{beforeInvocation}}
var result = {{invocationTarget}};
{{afterInvocation}}
""";
}
if (hasStructRewrite)
{
if (csReturnType.Kind == InteropTypeKind.Nullable)
implementation += Environment.NewLine + $$"""if (result != null) { *pReturnValue = ({{csOriginalInteropReturnType.GetFullyQualifiedName()}})result; return 1; } else { return 0; }""";
else
implementation += Environment.NewLine + $"*pReturnValue = result;";
}
else
{
implementation += Environment.NewLine + $"return {csReturnType.GetConversionToInteropType("result")};";
}
}
else if (property != null && SymbolEqualityComparer.Default.Equals(property.SetMethod, method))
{
if (property.IsIndexer && callParameterDetails.Count() >= 2)
{
// An element indexer (operator[])
var indexParameter = callParameterDetails.ElementAt(0);
var valueParameter = callParameterDetails.ElementAt(1);
implementation =
$$"""
{{beforeInvocation}}{{invocationTarget}}[{{indexParameter.Type.GetParameterConversionFromInteropType(indexParameter.Name)}}] = {{valueParameter.Type.GetParameterConversionFromInteropType(valueParameter.Name)}};{{afterInvocation}}
""";
}
else
{
// A property setter.
implementation =
$$"""
{{beforeInvocation}}{{invocationTarget}} = {{callParameterList}};{{afterInvocation}}
""";
}
}
else if (evt != null && SymbolEqualityComparer.Default.Equals(evt.AddMethod, method))
{
// An event adder
implementation =
$$"""
{{beforeInvocation}}{{invocationTarget}} += {{callParameterList}};{{afterInvocation}}
""";
}
else if (evt != null && SymbolEqualityComparer.Default.Equals(evt.RemoveMethod, method))
{
// An event adder
implementation =
$$"""
{{beforeInvocation}}{{invocationTarget}} -= {{callParameterList}};{{afterInvocation}}
""";
}
else if (method.MethodKind == MethodKind.UserDefinedOperator && method.Parameters.Length == 2)
{
// binary operator, like operator==
var lhs = callParameterDetails.ElementAt(0);
var rhs = callParameterDetails.ElementAt(1);
implementation =
$$"""
{{beforeInvocation}}
var result = ({{lhs.Type.GetParameterConversionFromInteropType(lhs.Name)}}) {{Interop.MethodNameToOperator(method.Name)}} ({{rhs.Type.GetParameterConversionFromInteropType(rhs.Name)}});
{{afterInvocation}}
return {{csReturnType.GetConversionToInteropType("result")}};
""";
}
else if (returnType.SpecialType == SpecialType.System_Void)
{
// Regular method returning void.
implementation =
$$"""
{{beforeInvocation}}{{invocationTarget}}({{callParameterList}});{{afterInvocation}}
""";
}
else if (hasStructRewrite)
{
// A method with a struct return value, rewritten to be a parameter instead for interop.
implementation =
$$"""
{{beforeInvocation}}
var result = {{invocationTarget}}({{callParameterList}});
{{afterInvocation}}
""";
if (csReturnType.Kind == InteropTypeKind.Nullable)
implementation += Environment.NewLine + $$"""if (result != null) { *pReturnValue = ({{csOriginalInteropReturnType.GetFullyQualifiedName()}})result; return 1; } else { return 0; }""";
else
implementation += Environment.NewLine + $"*pReturnValue = result;";
}
else
{
// Either a constructor or a regular method with a return value.
implementation =
$$"""
{{beforeInvocation}}
var result = {{invocationTarget}}({{callParameterList}});
{{afterInvocation}}
return {{csReturnType.GetConversionToInteropType("result")}};
""";
}
string baseName = GetUniqueNameForType(csType) + "_" + interopFunctionName;
return (
Name: $"{baseName}Delegate",
Content:
$$"""
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private unsafe delegate {{interopReturnTypeString}} {{baseName}}Type({{interopParameterList}});
private static unsafe readonly {{baseName}}Type {{baseName}}Delegate = new {{baseName}}Type({{baseName}});
[AOT.MonoPInvokeCallback(typeof({{baseName}}Type))]
private static unsafe {{interopReturnTypeString}} {{baseName}}({{interopParameterList}})
{
{{implementation.Replace(Environment.NewLine, Environment.NewLine + " ")}}
}
"""
);
}
/// <summary>
/// Creates a C# delegate, field of delegate type, and method/constructor/property to be invoked
/// by the delegate in order to provide a way for C++ code to access the given field.
/// </summary>
/// <param name="compilation">The compilation context.</param>
/// <param name="ownerType">The type that owns the method, constructor, or property.</param>
/// <param name="method">The method, constructor, or property getter/setter.</param>
/// <param name="isGet">True if this delegate provides the ability to GET the field, or false if it provides the ability to SET it.</param>
/// <returns>The Name and Content to add to the C# GeneratedInit functions list.</returns>
public static (string Name, string Content) CreateCSharpDelegateInit(
CppGenerationContext context,
ITypeSymbol ownerType,
IFieldSymbol field,
bool isGet)
{
CSharpType csType = CSharpType.FromSymbol(context, ownerType);
var parameters = isGet ? new (string Name, ITypeSymbol Type)[] { } : new[] { (Name: "value", Type: field.Type ) };
var returnType = isGet ? field.Type : context.Compilation.GetSpecialType(SpecialType.System_Void);
string accessName = field.Name;
var callParameterDetails = parameters.Select(parameter => (Name: parameter.Name, Type: CSharpType.FromSymbol(context, parameter.Type), InteropType: CSharpType.FromSymbol(context, parameter.Type).AsInteropTypeParameter()));
var interopParameterDetails = callParameterDetails;
string invocationTarget;
if (!field.IsStatic)
{
// Instance method or property
interopParameterDetails = new[] { (Name: "thiz", Type: csType, InteropType: csType.AsInteropTypeParameter()) }.Concat(interopParameterDetails);
invocationTarget = $"(({csType.GetFullyQualifiedName()})ObjectHandleUtility.GetObjectFromHandle(thiz)!).{accessName}";
}
else
{
// Static method or property
invocationTarget = $"{csType.GetFullyQualifiedName()}.{accessName}";
}
CSharpType csReturnType = CSharpType.FromSymbol(context, returnType);
CSharpType csInteropReturnType = csReturnType.AsInteropTypeReturn();
// Rewrite getters that return a blittable struct to instead taking a pointer to one.
// See Interop.RewriteStructReturn in this file for the C++ side of this and more
// explanation of why it's needed.
bool hasStructRewrite = false;
CSharpType csOriginalInteropReturnType = csInteropReturnType;
if (csReturnType.Kind == InteropTypeKind.BlittableStruct || csReturnType.Kind == InteropTypeKind.Nullable)
{
hasStructRewrite = true;
if (csReturnType.Kind == InteropTypeKind.Nullable)
csInteropReturnType = CSharpType.FromSymbol(context, context.Compilation.GetSpecialType(SpecialType.System_Byte));
else
csInteropReturnType = CSharpType.FromSymbol(context, context.Compilation.GetSpecialType(SpecialType.System_Void));
interopParameterDetails = interopParameterDetails.Concat(new[]
{
(Name: "pReturnValue", Type: csReturnType, InteropType: csOriginalInteropReturnType.AsPointer())
});
}
string interopReturnTypeString = csInteropReturnType.GetFullyQualifiedName();
string callParameterList = string.Join(", ", callParameterDetails.Select(parameter => parameter.Type.GetParameterConversionFromInteropType(parameter.Name)));
string interopParameterList = string.Join(", ", interopParameterDetails.Select(parameter => $"{parameter.InteropType.GetFullyQualifiedName()} {parameter.Name}"));
string implementation;
if (isGet)
{
implementation = $"var result = {invocationTarget};";
if (hasStructRewrite)
{
if (csReturnType.Kind == InteropTypeKind.Nullable)
implementation += Environment.NewLine + $$"""if (result != null) { *pReturnValue = ({{csOriginalInteropReturnType.GetFullyQualifiedName()}})result; return 1; } else { return 0; }""";
else
implementation += Environment.NewLine + $"*pReturnValue = result;";
}
else
{
implementation += Environment.NewLine + $"return {csReturnType.GetConversionToInteropType("result")};";
}
}
else
{
// A property setter.
implementation =
$$"""
{{invocationTarget}} = {{callParameterList}};
""";
}
string baseName = $"{GetUniqueNameForType(csType)}_Field_{(isGet ? "get" : "set")}_{field.Name}";
return (
Name: $"{baseName}Delegate",
Content:
$$"""
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private unsafe delegate {{interopReturnTypeString}} {{baseName}}Type({{interopParameterList}});
private static unsafe readonly {{baseName}}Type {{baseName}}Delegate = new {{baseName}}Type({{baseName}});
[AOT.MonoPInvokeCallback(typeof({{baseName}}Type))]
private static unsafe {{interopReturnTypeString}} {{baseName}}({{interopParameterList}})
{
{{implementation.Replace(Environment.NewLine, Environment.NewLine + " ")}}
}
"""
);
}
public static string GetUniqueNameForType(CSharpType type)
{
string name = type.Name;
string genericTypeHash = "";
INamedTypeSymbol? named = type.Symbol as INamedTypeSymbol;
if (named != null && named.IsGenericType)
{
genericTypeHash = HashParameters(null, named.TypeArguments);
}
IArrayTypeSymbol? arraySymbol = type.Symbol as IArrayTypeSymbol;
if (arraySymbol != null)
{
name = "Array1";
genericTypeHash = HashParameters(null, new[] { arraySymbol.ElementType });
}
return $"{type.GetFullyQualifiedNamespace().Replace(".", "_")}_{name}{genericTypeHash}";
}
public static void GenerateForType(CppGenerationContext context, TypeToGenerate item, GeneratedResult result)
{
string initializeReinteropHeader = context.BaseNamespace == null ? "<initializeReinterop.h>" : $"<{context.BaseNamespace.Replace("::", "/")}/initializeReinterop.h>";
result.CppDeclaration.Elements.Add(new(
Content: "friend std::uint8_t (::initializeReinterop)(std::uint64_t validationHash, void** functionPointers, std::int32_t count);",
IsPrivate: true,
TypeDeclarationsReferenced: new[] { CppType.UInt8, CppType.Int32, CppType.UInt64 },
AdditionalIncludes: new[] { initializeReinteropHeader }));
}
public static string InsecureHash(string s)
{
byte[] bytes = Encoding.UTF8.GetBytes(s);
using (MD5 md5 = MD5.Create())
{
byte[] hash = md5.ComputeHash(bytes);
return System.Convert.ToBase64String(hash);
}
}
public static ulong InsecureHash64bits(string s)
{
byte[] bytes = Encoding.UTF8.GetBytes(s);
using (MD5 md5 = MD5.Create())
{
byte[] hash = md5.ComputeHash(bytes);
ulong result = 0;
for (int i = 0; i < sizeof(ulong) && i < hash.Length; ++i)
{
result <<= 8;
result |= hash[i];
}
return result;
}
}
public static string HashParameters(IEnumerable<IParameterSymbol>? parameters = null, IEnumerable<ITypeSymbol>? typeArguments = null)
{
IEnumerable<string>? formattedParameters = null;
IEnumerable<string>? formattedTypeArguments = null;
if (parameters != null)
formattedParameters = parameters.Select(parameter => $"{parameter.Type.ToDisplayString()} {parameter.Name}");
if (typeArguments != null)
formattedTypeArguments = typeArguments.Select(arg => $"<{arg.ToDisplayString()}>");
IEnumerable<string>? allFormattedInput = null;
if (formattedParameters != null && formattedTypeArguments != null)
allFormattedInput = formattedTypeArguments.Concat(formattedParameters);
else if (formattedParameters != null)
allFormattedInput = formattedParameters;
else if (formattedTypeArguments != null)
allFormattedInput = formattedTypeArguments;
else
allFormattedInput = new string[] { };
var allTogether = string.Join(", ", allFormattedInput);
string hash = InsecureHash(allTogether);
return hash.Replace("=", "").Replace("+", "_").Replace("/", "__");
}
public static InteropTypeKind DetermineTypeKind(CppGenerationContext context, ITypeSymbol type)
{
if (type.Kind == SymbolKind.TypeParameter)
return InteropTypeKind.GenericParameter;
switch (type.SpecialType)
{
case SpecialType.System_SByte:
case SpecialType.System_Int16:
case SpecialType.System_Int32:
case SpecialType.System_Int64:
case SpecialType.System_Single:
case SpecialType.System_Double:
case SpecialType.System_Byte:
case SpecialType.System_UInt16:
case SpecialType.System_UInt32:
case SpecialType.System_UInt64:
case SpecialType.System_Boolean:
case SpecialType.System_IntPtr:
case SpecialType.System_Void:
return InteropTypeKind.Primitive;
}
INamedTypeSymbol? named = type as INamedTypeSymbol;
if (named != null && named.Name == "Nullable" && named.TypeArguments.Length == 1)
return InteropTypeKind.Nullable;
else if (SymbolEqualityComparer.Default.Equals(type.BaseType, context.Compilation.GetSpecialType(SpecialType.System_Enum))) {
if (type.GetAttributes().Where(attrib => attrib.AttributeClass != null && (attrib.AttributeClass.Name == "FlagsAttribute" || attrib.AttributeClass.Name == "Flags")).Any()) {
return InteropTypeKind.EnumFlags;
} else {
return InteropTypeKind.Enum;
}
} else if (type.TypeKind == TypeKind.Delegate)
return InteropTypeKind.Delegate;
else if (type.IsReferenceType)
return InteropTypeKind.ClassWrapper;
else if (type is IPointerTypeSymbol)
return InteropTypeKind.Primitive;
else if (IsBlittableStruct(context, type))
return InteropTypeKind.BlittableStruct;
else
return InteropTypeKind.NonBlittableStructWrapper;
}
/// <summary>
/// Determines if the given type is a blittable value type (struct).
/// </summary>
/// <param name="compilation"></param>
/// <param name="type"></param>
/// <returns>True if the struct is blittable.</returns>
public static bool IsBlittableStruct(CppGenerationContext context, ITypeSymbol type, int depth = 0)
{
// Sanity test to avoid a stack overflow
if (depth > 10)
return false;
// We construct a name rather than using `type.ToDisplayString()` here so that
// entire generic types can be listed as unblittable.
string name = type.ContainingNamespace != null ? type.ContainingNamespace.ToDisplayString() + "." : "";
name += type.Name;
if (name.Length > 0 && context.NonBlittableTypes.Contains(name))
return false;
if (!type.IsValueType)
return false;
if (IsBlittablePrimitive(type))
return true;
ImmutableArray<ISymbol> members = type.GetMembers();
foreach (ISymbol member in members)
{
if (member.Kind != SymbolKind.Field)
continue;
IFieldSymbol? field = member as IFieldSymbol;
if (field == null || field.IsStatic)
continue;
if (!IsBlittableStruct(context, field.Type, depth + 1))
return false;
}
return true;
}
private static bool IsBlittablePrimitive(ITypeSymbol type)
{
if (type.TypeKind == TypeKind.Enum)
return true;
switch (type.SpecialType)
{
case SpecialType.System_Byte:
case SpecialType.System_SByte:
case SpecialType.System_Int16:
case SpecialType.System_UInt16:
case SpecialType.System_Int32:
case SpecialType.System_UInt32:
case SpecialType.System_Int64:
case SpecialType.System_UInt64:
case SpecialType.System_IntPtr:
case SpecialType.System_UIntPtr:
case SpecialType.System_Single:
case SpecialType.System_Double:
case SpecialType.System_Boolean:
return true;
default:
return false;
}
}
public static List<string> BuildNamespace(string? baseNamespace, params string[] namespaces)
{
List<string> result = new List<string>();
if (!string.IsNullOrEmpty(baseNamespace) && (namespaces.Length == 0 || namespaces[0] != baseNamespace))
result.Add(baseNamespace!);
result.AddRange(namespaces);
return result;
}
public static string GetTemplateSpecialization(CppType type)
{
string templateSpecialization = "";
if (type.GenericArguments != null && type.GenericArguments.Count > 0)
{
templateSpecialization = $"<{string.Join(", ", type.GenericArguments.Select(arg => arg.GetFullyQualifiedName()))}>";
}
return templateSpecialization;
}
public static string MethodNameToOperator(string methodName)
{
switch (methodName)
{
case "op_Equality":
return "==";
case "op_Inequality":
return "!=";
default:
throw new Exception("Unsupported operator " + methodName);
}
}
/// <summary>
/// Mono has trouble return large structs from C# to C++. See https://github.com/CesiumGS/cesium-unity/issues/73.
/// This rewrites the interop for such a method so that the C++ code instead passes a pointer to the
/// struct which is filled in on the C# side.
/// </summary>
/// <param name="interopParameters">The parameters to the interop method.</param>
/// <param name="interopReturnType">The return type of the interop method.</param>
/// <returns>True if the method has been rewritten, otherwise false.</returns>
public static bool RewriteStructReturn(ref IEnumerable<(string ParameterName, string CallSiteName, CppType Type, CppType InteropType)> interopParameters, ref CppType returnType, ref CppType interopReturnType)
{
if (returnType.Kind == InteropTypeKind.BlittableStruct)
{
CppType originalInteropReturnType = interopReturnType;
interopReturnType = CppType.Void;
interopParameters = interopParameters.Concat(new[]
{
(ParameterName: "pReturnValue", CallSiteName: "result", Type: returnType.AsReference(), InteropType: originalInteropReturnType.AsPointer())
});
return true;
}
else if (returnType.Kind == InteropTypeKind.Nullable &&
(interopReturnType.Kind == InteropTypeKind.BlittableStruct ||
interopReturnType.Kind == InteropTypeKind.Primitive))
{
CppType originalInteropReturnType = interopReturnType;
interopReturnType = CppType.UInt8;
interopParameters = interopParameters.Concat(new[]
{
(ParameterName: "pReturnValue", CallSiteName: "result", Type: originalInteropReturnType.AsReference(), InteropType: originalInteropReturnType.AsPointer())
});
return true;
}
return false;
}
}
}