private IEnumerable<Instruction> GetCommandInitializationInstructions(CommandData commandData)
{
Instruction blockEnd = Instruction.Create(OpCodes.Nop);
//// Null check
//// if (Command == null) { ... }
yield return Instruction.Create(OpCodes.Nop);
yield return Instruction.Create(OpCodes.Ldarg_0);
yield return Instruction.Create(OpCodes.Call, commandData.CommandProperty.GetMethod);
yield return Instruction.Create(OpCodes.Ldnull);
yield return Instruction.Create(OpCodes.Ceq);
yield return Instruction.Create(OpCodes.Ldc_I4_0);
yield return Instruction.Create(OpCodes.Ceq);
yield return Instruction.Create(OpCodes.Stloc_0);
yield return Instruction.Create(OpCodes.Ldloc_0);
yield return Instruction.Create(OpCodes.Brtrue_S, blockEnd);
foreach (var instruction in GetSetCommandInstructions(commandData))
{
yield return instruction;
}
// BlockEnd is the end of the if (Command == null) {} block (i.e. think the closing brace)
yield return blockEnd;
}
internal IEnumerable<Instruction> GetSetCommandInstructions(CommandData command)
{
var commandConstructors = Assets.CommandImplementationConstructors;
if (Assets.DelegateCommandImplementationWasInjected)
{
var delegateCommandType = Assets.ModuleDefinition.GetType(DelegateCommandClassInjectionProcessor.GeneratedCommandClassName);
commandConstructors = commandConstructors.Concat(delegateCommandType.GetConstructors()).ToList();
}
if (command.OnExecuteMethods.Count > 0)
{
MethodReference commandConstructor;
var onExecuteMethod = command.OnExecuteMethods[0];
var canExecuteMethod = command.CanExecuteMethods.FirstOrDefault();
if (canExecuteMethod == null)
{
commandConstructor = commandConstructors.FirstOrDefault(mf=>mf.Parameters.Count == 1);
commandConstructor = GetConstructorResolved(commandConstructor, onExecuteMethod);
yield return Instruction.Create(OpCodes.Ldarg_0);
yield return Instruction.Create(OpCodes.Ldarg_0);
yield return Instruction.Create(OpCodes.Ldftn, onExecuteMethod);
yield return Instruction.Create(OpCodes.Newobj, GetActionConstructorForExecuteMethod(onExecuteMethod, commandConstructor));
yield return Instruction.Create(OpCodes.Newobj, commandConstructor);
yield return Instruction.Create(OpCodes.Call, command.CommandProperty.SetMethod);
yield return Instruction.Create(OpCodes.Nop);
yield return Instruction.Create(OpCodes.Nop);
}
else
{
commandConstructor = commandConstructors.OrderByDescending(mf => mf.Parameters.Count).First();
commandConstructor = GetConstructorResolved(commandConstructor, onExecuteMethod);
yield return Instruction.Create(OpCodes.Nop);
yield return Instruction.Create(OpCodes.Ldarg_0);
yield return Instruction.Create(OpCodes.Ldarg_0);
yield return Instruction.Create(OpCodes.Ldftn, command.OnExecuteMethods.Single());
yield return Instruction.Create(OpCodes.Newobj, GetActionConstructorForExecuteMethod(onExecuteMethod, commandConstructor));
yield return Instruction.Create(OpCodes.Ldarg_0);
yield return Instruction.Create(OpCodes.Ldftn, command.CanExecuteMethods.Single());
yield return Instruction.Create(OpCodes.Newobj, GetPredicateConstructorForCanExecuteMethod(canExecuteMethod, commandConstructor));
yield return Instruction.Create(OpCodes.Newobj, commandConstructor);
yield return Instruction.Create(OpCodes.Call, command.CommandProperty.SetMethod);
yield return Instruction.Create(OpCodes.Nop);
yield return Instruction.Create(OpCodes.Nop);
}
}
}
public bool TryAddCommandPropertyInitialization(MethodDefinition initializeMethod, CommandData commandData)
{
if (!Assets.CommandImplementationConstructors.Any())
{
if (!Assets.DelegateCommandImplementationWasInjected)
{
Assets.Log.Info("Skipped command initialization for command {0}, because there is no eligible command implementation to bind to.", commandData);
return false;
}
}
if (!initializeMethod.Body.Variables.Any(vDef => vDef.VariableType.IsBoolean() && vDef.Name == "isNull"))
{
var vDef = new VariableDefinition("isNull", Type.Module.TypeSystem.Boolean);
initializeMethod.Body.Variables.Add(vDef);
}
var instructions = initializeMethod.Body.Instructions;
GetOrCreateLastReturnInstruction(initializeMethod);
var instructionsToAdd = GetCommandInitializationInstructions(commandData).ToArray();
instructions.Prepend(instructionsToAdd);
commandData.CommandInitializationInjected = true;
return true;
}