internal static AsyncClass Create(IBlockContext parent, string name, TO2Type declaredReturn,
List <FunctionParameter> parameters, Expression expression)
{
Type returnType = declaredReturn.GeneratedType(parent.ModuleContext);
Type typeParameter = returnType == typeof(void) ? typeof(object) : returnType;
ModuleContext asyncModuleContext = parent.ModuleContext.DefineSubContext($"AsyncFunction_{name}",
typeof(Future <>).MakeGenericType(typeParameter));
List <ClonedFieldVariable> clonedParameters = new List <ClonedFieldVariable>();
foreach (FunctionParameter parameter in parameters)
{
FieldBuilder field = asyncModuleContext.typeBuilder.DefineField(parameter.name,
parameter.type.GeneratedType(parent.ModuleContext), FieldAttributes.Private);
clonedParameters.Add(
new ClonedFieldVariable(parameter.type.UnderlyingType(parent.ModuleContext), field));
}
// ------------- PollValue -------------
AsyncBlockContext asyncContext = new AsyncBlockContext(asyncModuleContext, FunctionModifier.Public,
"PollValue", declaredReturn, typeof(FutureResult <>).MakeGenericType(typeParameter), clonedParameters);
LabelRef applyState = asyncContext.IL.DefineLabel(false);
LabelRef initialState = asyncContext.IL.DefineLabel(false);
asyncContext.IL.Emit(OpCodes.Br, applyState);
asyncContext.IL.MarkLabel(initialState);
expression.EmitCode(asyncContext, false);
if (!asyncContext.HasErrors)
{
declaredReturn.AssignFrom(asyncContext.ModuleContext, expression.ResultType(asyncContext))
.EmitConvert(asyncContext);
}
asyncContext.IL.EmitNew(OpCodes.Newobj,
asyncContext.MethodBuilder.ReturnType.GetConstructor(new[] { typeParameter }));
asyncContext.IL.EmitReturn(asyncContext.MethodBuilder.ReturnType);
// Apply state
asyncContext.IL.MarkLabel(applyState);
asyncContext.IL.Emit(OpCodes.Ldarg_0);
asyncContext.IL.Emit(OpCodes.Ldfld, asyncContext.stateField);
asyncContext.IL.Emit(OpCodes.Switch,
initialState.Yield().Concat(asyncContext.asyncResumes.Select(ar => ar.pollLabel)));
asyncContext.IL.Emit(OpCodes.Ldarg_0);
asyncContext.IL.Emit(OpCodes.Ldfld, asyncContext.stateField);
asyncContext.IL.EmitNew(OpCodes.Newobj,
typeof(InvalidAsyncStateException).GetConstructor(new[] { typeof(int) }), 1);
asyncContext.IL.Emit(OpCodes.Throw);
foreach (AsyncResume asyncResume in asyncContext.asyncResumes)
{
asyncResume.EmitPoll(asyncContext);
}
// Restore state
asyncContext.IL.MarkLabel(asyncContext.resume);
foreach (StateRef stateRef in asyncContext.stateRefs)
{
stateRef.EmitRestore(asyncContext);
}
asyncContext.IL.Emit(OpCodes.Ldarg_0);
asyncContext.IL.Emit(OpCodes.Ldfld, asyncContext.stateField);
asyncContext.IL.Emit(OpCodes.Switch,
initialState.Yield().Concat(asyncContext.asyncResumes.Select(ar => ar.resumeLabel)));
asyncContext.IL.Emit(OpCodes.Ldarg_0);
asyncContext.IL.Emit(OpCodes.Ldfld, asyncContext.stateField);
asyncContext.IL.EmitNew(OpCodes.Newobj,
typeof(InvalidAsyncStateException).GetConstructor(new[] { typeof(int) }), 1);
asyncContext.IL.Emit(OpCodes.Throw);
// Store state
asyncContext.IL.MarkLabel(asyncContext.storeState);
foreach (StateRef stateRef in asyncContext.stateRefs)
{
stateRef.EmitStore(asyncContext);
}
asyncContext.IL.MarkLabel(asyncContext.notReady);
using (ITempLocalRef notReady = asyncContext.IL.TempLocal(asyncContext.MethodBuilder.ReturnType)) {
notReady.EmitLoadPtr(asyncContext);
asyncContext.IL.Emit(OpCodes.Initobj, asyncContext.MethodBuilder.ReturnType, 1, 0);
notReady.EmitLoad(asyncContext);
asyncContext.IL.EmitReturn(asyncContext.MethodBuilder.ReturnType);
}
foreach (StructuralError error in asyncContext.AllErrors)
{
parent.AddError(error);
}
// ------------- Constructor -------------
List <FieldInfo> parameterFields = clonedParameters.Select(c => c.valueField).ToList();
ConstructorBuilder constructorBuilder = asyncModuleContext.typeBuilder.DefineConstructor(
MethodAttributes.Public, CallingConventions.Standard,
parameterFields.Select(f => f.FieldType).ToArray());
IILEmitter constructorEmitter = new GeneratorILEmitter(constructorBuilder.GetILGenerator());
int argIndex = 1;
foreach (FieldInfo field in parameterFields)
{
constructorEmitter.Emit(OpCodes.Ldarg_0);
MethodParameter.EmitLoadArg(constructorEmitter, argIndex++);
constructorEmitter.Emit(OpCodes.Stfld, field);
}
constructorEmitter.Emit(OpCodes.Ldarg_0);
constructorEmitter.Emit(OpCodes.Ldc_I4_0);
constructorEmitter.Emit(OpCodes.Stfld, asyncContext.stateField);
constructorEmitter.EmitReturn(typeof(void));
return(new AsyncClass(asyncModuleContext.typeBuilder, constructorBuilder));
}
