/// <summary>
/// Create an adhoc variable used to retain an instance of an attribute.
/// </summary>
/// <param name="method">The method weaver.</param>
/// <param name="attribute">The attribute.</param>
/// <param name="member">The member.</param>
/// <returns></returns>
public Variable CreateAttributeAdhoc(MethodEmitter method, CustomAttribute attribute, MemberReference member)
{
var type = attribute.AttributeType;
var variable = method.EmitLocal(type);
var il = method.GetIL();
foreach (var arg in attribute.ConstructorArguments)
{
CreateAttributeParameter(method, attribute, arg);
}
il.Emit(Codes.Create(attribute.Constructor));
il.Emit(Codes.Store(variable));
if (attribute.HasInterface(Context.Finder.IInstanceAware) && !method.Target.IsStatic)
{
il.Emit(Codes.Load(variable));
il.Emit(Codes.This);
il.Emit(Codes.Invoke(Context.Finder.InstanceAwareInstanceSet));
}
foreach (var prop in attribute.Properties)
{
CreateAttributeProperty(method, attribute, variable, prop);
}
CreateAttributeRequirements(il, attribute, member, variable, false);
return(variable);
}
/// <summary>
/// Copies the values of an array of parameter values into the corresponding parameters.
/// </summary>
/// <param name="method">The method.</param>
/// <param name="array">The array.</param>
public void CopyArgumentArrayToParameters(MethodEmitter method, Variable array)
{
var parameters = method.Target.Parameters;
var count = parameters.Count;
var il = method.GetIL();
for (int i = 0; i < count; i++)
{
var p = parameters[i];
var variable = new Variable(p);
var type = p.ParameterType;
if (type.IsByReference || p.IsOut)
{
continue;
}
il.Emit(Codes.Load(array));
il.Emit(Codes.Int(i));
il.Emit(Codes.LoadArray);
il.Emit(Codes.Unbox(type));
il.Emit(Codes.Store(variable));
}
CopyArgumentArrayToReferences(method, array);
}
/// <summary>
/// Creates a reference to a parameter used in a custom attribute.
/// </summary>
/// <param name="emitter">The emitter.</param>
/// <param name="attribute">The attribute.</param>
/// <param name="arg">The argument.</param>
public void CreateAttributeParameter(MethodEmitter emitter, CustomAttribute attribute, CustomAttributeArgument arg)
{
var il = emitter.GetIL();
if (arg.Value == null)
{
il.Emit(Codes.Null);
return;
}
var type = arg.Type;
if (type.IsArray)
{
var elements = (arg.Value as IEnumerable).Cast <CustomAttributeArgument>().ToArray();
il.Emit(Codes.Int(elements.Length));
il.Emit(Codes.CreateArray(type.GetElementType()));
if (elements.Length == 0)
{
return;
}
il.Emit(Codes.Duplicate);
for (int i = 0, count = elements.Length; i < count; i++)
{
il.Emit(Codes.Int(i));
if (elements[i].Value == null)
{
il.Emit(Codes.Null);
il.Emit(Codes.StoreArray);
}
else
{
il.Emit(Codes.Load(elements[i].Value));
il.Emit(Codes.StoreArray);
}
if (i + 1 < count)
{
il.Emit(Codes.Duplicate);
}
}
}
else
{
il.Emit(Codes.Load(arg.Value));
}
}
/// <summary>
/// Creates a reference to a property used in a custom attribute.
/// </summary>
/// <param name="emitter">The emitter.</param>
/// <param name="attribute">The attribute.</param>
/// <param name="field">The attribute variable.</param>
/// <param name="property">The property.</param>
public void CreateAttributeProperty(MethodEmitter emitter, CustomAttribute attribute, Variable field, Mono.Cecil.CustomAttributeNamedArgument property)
{
var il = emitter.GetIL();
var member = field.Type.Resolve().Properties.FirstOrDefault(p => p.Name == property.Name)?.SetMethod;
if (member == null)
{
throw new MissingMemberException($"Cannot resolve property {property.Name} of {attribute.AttributeType.Name} as there is no setter");
}
il.Emit(Codes.ThisIf(field));
il.Emit(Codes.Load(field));
CreateAttributeParameter(emitter, attribute, property.Argument);
il.Emit(Codes.Invoke(member.Import()));
}
/// <summary>
/// Weaves the return instructions of the provided method to leave to a new instruction.
/// </summary>
/// <param name="weaver">The method weaver.</param>
/// <param name="storage">The storage variable for any captured return value.</param>
/// <param name="hasMethodInterceptors">Whether method interceptors are present which could change the return value.</param>
/// <returns>The instruction now located at the tail of the method.</returns>
public Instruction WeaveMethodReturnsRoute(MethodEmitter weaver, Variable storage, bool hasMethodInterceptors)
{
var il = weaver.Body.Instructions;
var pos = weaver.GetIL().Position;
var instruction = (Instruction)null;
if (weaver.Target.IsReturn())
{
instruction = hasMethodInterceptors ? Codes.Nop : Codes.Load(storage);
il.Add(instruction);
il.Add(Codes.Return);
for (int i = 0; i < il.Count - 2; i++)
{
if (il[i].OpCode == OpCodes.Ret)
{
var store = Codes.Store(storage);
il[i].OpCode = store.OpCode;
il[i].Operand = store.Operand;
weaver.Body.GetILProcessor().InsertAfter(il[i], Codes.Leave(instruction));
}
}
}
else
{
instruction = Codes.Return;
il.Add(instruction);
for (int i = 0, count = il.Count - 1; i < count; i++)
{
var ix = il[i];
if (ix.OpCode == OpCodes.Ret)
{
ix.OpCode = OpCodes.Leave;
ix.Operand = instruction;
}
}
}
return(instruction);
}
/// <summary>
/// Copies the values of an array of parameter values into the required references.
/// </summary>
/// <param name="method">The method.</param>
/// <param name="array">The array.</param>
public void CopyArgumentArrayToReferences(MethodEmitter method, Variable array)
{
var parameters = method.Target.Parameters;
var count = parameters.Count;
var il = method.GetIL();
for (int i = 0; i < count; i++)
{
var p = parameters[i];
var type = p.ParameterType;
if (!type.IsByReference || p.IsOut)
{
continue;
}
var spec = (TypeSpecification)type;
var unboxing = true;
il.Emit(Codes.Arg(p));
il.Emit(Codes.Load(array));
il.Emit(Codes.Int(i));
il.Emit(Codes.LoadArray);
var code = OpCodes.Nop;
switch (spec.ElementType.MetadataType)
{
case MetadataType.Boolean:
case MetadataType.SByte:
case MetadataType.Byte:
code = OpCodes.Stind_I1;
break;
case MetadataType.Int16:
case MetadataType.UInt16:
code = OpCodes.Stind_I2;
break;
case MetadataType.Int32:
case MetadataType.UInt32:
code = OpCodes.Stind_I4;
break;
case MetadataType.Int64:
case MetadataType.UInt64:
code = OpCodes.Stind_I8;
break;
case MetadataType.Single:
code = OpCodes.Stind_R4;
break;
case MetadataType.Double:
code = OpCodes.Stind_R8;
break;
case MetadataType.IntPtr:
case MetadataType.UIntPtr:
code = OpCodes.Stind_I;
break;
default:
if (spec.ElementType.IsValueType)
{
il.Emit(Instruction.Create(OpCodes.Stobj, spec.ElementType));
}
else
{
code = OpCodes.Stind_Ref;
unboxing = false;
}
break;
}
if (unboxing)
{
il.Emit(Codes.Unbox(spec.ElementType));
}
if (code != OpCodes.Nop)
{
il.Emit(code);
}
}
}
/// <summary>
/// Create an array variable containing the arguments of the method invocation.
/// </summary>
/// <param name="method">The method weaver.</param>
/// <returns></returns>
public Variable CreateArgumentArray(MethodEmitter method)
{
var parameters = method.Target.Parameters;
var count = parameters.Count;
var array = method.EmitLocal(Context.Finder.ObjectArray);
var il = method.GetIL();
il.Emit(Codes.Nop);
il.Emit(Codes.Int(count));
il.Emit(Codes.CreateArray(TypeSystem.ObjectReference));
il.Emit(Codes.Store(array));
for (int i = 0; i < count; i++)
{
var p = parameters[i];
var type = p.ParameterType;
il.Emit(Codes.Load(array));
il.Emit(Codes.Int(i));
if (p.IsOut)
{
var spec = (TypeSpecification)type;
if (spec.ElementType.IsValueType)
{
il.Emit(Codes.Init(spec.ElementType));
}
else
{
il.Emit(Codes.Null);
il.Emit(Codes.StoreArray);
}
continue;
}
il.Emit(Codes.Arg(p));
if (type.IsByReference)
{
var spec = (TypeSpecification)type;
var boxing = true;
switch (spec.ElementType.MetadataType)
{
case MetadataType.SByte:
il.Emit(OpCodes.Ldind_I1);
break;
case MetadataType.Int16:
il.Emit(OpCodes.Ldind_I2);
break;
case MetadataType.Int32:
il.Emit(OpCodes.Ldind_I4);
break;
case MetadataType.Int64:
case MetadataType.UInt64:
il.Emit(OpCodes.Ldind_I8);
break;
case MetadataType.Boolean:
case MetadataType.Byte:
il.Emit(OpCodes.Ldind_U1);
break;
case MetadataType.UInt16:
il.Emit(OpCodes.Ldind_U2);
break;
case MetadataType.UInt32:
il.Emit(OpCodes.Ldind_U4);
break;
case MetadataType.Single:
il.Emit(OpCodes.Ldind_R4);
break;
case MetadataType.Double:
il.Emit(OpCodes.Ldind_R8);
break;
case MetadataType.IntPtr:
case MetadataType.UIntPtr:
il.Emit(OpCodes.Ldind_I);
break;
default:
if (spec.ElementType.IsValueType)
{
il.Emit(Instruction.Create(OpCodes.Ldobj, spec.ElementType));
}
else
{
il.Emit(OpCodes.Ldind_Ref);
boxing = false;
}
break;
}
if (boxing)
{
il.Emit(Codes.Box(spec.ElementType));
}
}
else
{
il.Emit(Codes.Box(p.ParameterType));
}
il.Emit(Codes.StoreArray);
}
return(array);
}
/// <summary>
/// Weaves the interception logic of a method.
/// </summary>
/// <param name="weaver">The method weaver.</param>
/// <param name="item">The method information.</param>
public void WeaveMethodInterceptors(MethodEmitter weaver, MethodInterceptorInfo item)
{
weaver.Body.SimplifyMacros();
var pAttributes = item.Parameters.SelectMany(p => p.Attributes.Select(a => new { p.Index, Attribute = a })).ToArray();
var mAttributes = item.MethodInterceptors;
var rAttributes = item.ReturnInterceptors;
var pInterceptors = new Variable[pAttributes.Length];
var mInterceptors = new Variable[item.MethodInterceptors.Length];
var rInterceptors = new Variable[rAttributes.Length];
var needsEnter = mAttributes.Any(m => m.HasRequiredMethod(Context.Finder.MethodInterceptorOnEnter));
var needsCatch = mAttributes.Any(m => m.HasRequiredMethod(Context.Finder.MethodInterceptorOnException));
var needsExit = mAttributes.Any(m => m.HasRequiredMethod(Context.Finder.MethodInterceptorOnExit));
var needsParams = pAttributes.Any(m => m.Attribute.HasRequiredMethod(Context.Finder.ParameterInterceptorOnEnter));
var needsReturns = rAttributes.Any(m => m.HasRequiredMethod(Context.Finder.MethodReturnInterceptorOnReturn));
var needsMethodArgs = mAttributes.Any(m =>
{
return(m.AttributeType.GetMethod(Context.Finder.MethodInterceptorOnEnter).UsesParameter(0) ||
m.AttributeType.GetMethod(Context.Finder.MethodInterceptorOnException).UsesParameter(0) ||
m.AttributeType.GetMethod(Context.Finder.MethodInterceptorOnExit).UsesParameter(0));
});
var needsParamArgs = pAttributes.Any(m => m.Attribute.AttributeType.GetMethod(Context.Finder.ParameterInterceptorOnEnter).UsesParameter(0));
var needsReturnsArgs = rAttributes.Any(m => m.AttributeType.GetMethod(Context.Finder.MethodReturnInterceptorOnReturn).UsesParameter(0));
var needsMethodCopyArgs = mAttributes.Any(m => m.GetAttribute(Context.Finder.CompilationOptionsAttribute)?.GetProperty("CopyArguments", notFound: false) ?? false);
if (!needsEnter && !needsCatch && !needsExit && !needsParams && !needsReturns)
{
return;
}
var method = weaver.Target;
var il = weaver.GetIL();
il.Position = il.GetFirst();
il.Insert = CodeInsertion.Before;
var result = (Variable)null;
if (weaver.Target.IsReturn())
{
var type = weaver.Target.ReturnType;
result = weaver.EmitLocal(type);
if (type.IsValueType)
{
il.Emit(Codes.Address(result));
il.Emit(Codes.Init(type));
}
else
{
il.Emit(Codes.Null);
il.Emit(Codes.Store(result));
}
}
var leave = WeaveMethodReturnsRoute(weaver, result, mInterceptors.Length > 0);
var cancel = il.EmitLabel();
for (int i = 0, count = pInterceptors.Length; i < count; i++)
{
pInterceptors[i] = CreateAttribute(weaver, pAttributes[i].Attribute);
}
for (int i = 0, count = mInterceptors.Length; i < count; i++)
{
mInterceptors[i] = CreateAttribute(weaver, mAttributes[i]);
}
for (int i = 0, count = rInterceptors.Length; i < count; i++)
{
rInterceptors[i] = CreateAttribute(weaver, rAttributes[i]);
}
foreach (var attribute in mAttributes)
{
weaver.Target.CustomAttributes.Remove(attribute);
}
foreach (var attribute in pAttributes)
{
if (attribute.Index == -1)
{
weaver.Target.CustomAttributes.Remove(attribute.Attribute);
}
else
{
weaver.Target.Parameters[attribute.Index].CustomAttributes.Remove(attribute.Attribute);
}
}
foreach (var attribute in rAttributes)
{
weaver.Target.MethodReturnType.CustomAttributes.Remove(attribute);
}
foreach (var parameter in item.Parameters)
{
foreach (var attribute in parameter.Attributes)
{
if (parameter.Index == -1)
{
weaver.Target.CustomAttributes.Remove(attribute);
}
else
{
weaver.Target.Parameters[parameter.Index].CustomAttributes.Remove(attribute);
}
}
}
var hasMethod = mInterceptors.Length > 0;
var hasParams = pInterceptors.Length > 0;
var hasReturn = rInterceptors.Length > 0;
var arguments = hasMethod ? CreateArgumentArray(weaver) : null;
var invocation = CreateMethodInfo(weaver);
var mEventArgs = hasMethod && needsMethodArgs?weaver.EmitLocal(Context.Finder.MethodInterceptionArgs, name : "methodEventArgs") : null;
if (hasMethod || hasReturn)
{
if (hasMethod && needsMethodArgs)
{
il.Emit(method.IsStatic ? Codes.Null : Codes.This);
il.Emit(Codes.Load(arguments));
if (result == null)
{
il.Emit(Codes.Null);
}
else
{
il.Emit(Codes.Load(result));
il.Emit(Codes.Box(result.Type));
}
il.Emit(Codes.Load(invocation));
il.Emit(Codes.Create(Context.Finder.MethodInterceptionArgsCtor));
il.Emit(Codes.Store(mEventArgs));
}
il.Try();
}
if (hasParams && needsParams)
{
var pEventArgs = needsParamArgs ? weaver.EmitLocal(Context.Finder.ParameterInterceptionArgs) : null;
for (int i = 0, count = pInterceptors.Length; i < count; i++)
{
var inc = pInterceptors[i];
var parameters = pAttributes[i].Index == -1 ? method.Parameters.ToArray() : new[] { method.Parameters[pAttributes[i].Index] };
for (int j = 0, pCount = parameters.Length; j < pCount; j++)
{
var prm = parameters[j];
var pVariable = new Variable(prm);
var pInfo = CreateParameterInfo(weaver, prm);
var needsCopyArgs = pAttributes[i].Attribute.GetAttribute(Context.Finder.CompilationOptionsAttribute)?.GetProperty("CopyArguments", notFound: false) ?? false;
if (needsParamArgs)
{
il.Emit(method.IsStatic ? Codes.Null : Codes.This);
il.Emit(Codes.Load(pInfo));
il.Emit(Codes.Arg(pVariable));
il.Emit(Codes.Box(prm.ParameterType));
il.Emit(Codes.Create(Context.Finder.ParameterInterceptionArgsCtor));
il.Emit(Codes.Store(pEventArgs));
}
il.Emit(Codes.ThisIf(inc));
il.Emit(Codes.Load(inc));
if (needsParamArgs)
{
il.Emit(Codes.Load(pEventArgs));
}
else
{
il.Emit(Codes.Null);
}
il.Emit(Codes.Invoke(Context.Finder.ParameterInterceptorOnEnter));
if (needsParamArgs && !prm.IsOut && needsCopyArgs)
{
il.Emit(Codes.Load(pEventArgs));
il.Emit(Codes.Invoke(Context.Finder.ParameterInterceptionArgsValueGet));
il.Emit(Codes.Unbox(prm.ParameterType));
il.Emit(Codes.Store(pVariable));
}
}
}
}
if (hasMethod || hasReturn)
{
if (hasMethod && needsEnter)
{
for (int i = 0, count = mInterceptors.Length; i < count; i++)
{
var inc = mInterceptors[i];
var att = mAttributes[i];
if (att.HasRequiredMethod("OnEnter"))
{
il.Emit(Codes.ThisIf(inc));
il.Emit(Codes.Load(inc));
if (needsMethodArgs)
{
il.Emit(Codes.Load(mEventArgs));
}
else
{
il.Emit(Codes.Null);
}
il.Emit(Codes.Invoke(Context.Finder.MethodInterceptorOnEnter));
if (needsMethodArgs)
{
var proceed = il.EmitLabel();
il.Emit(Codes.Load(mEventArgs));
il.Emit(Codes.Invoke(Context.Finder.MethodInterceptionArgsCancelGet));
il.Emit(Codes.IfFalse(proceed));
if (result != null && needsMethodArgs)
{
il.Emit(Codes.Load(mEventArgs));
il.Emit(Codes.Invoke(Context.Finder.MethodInterceptionArgsReturnGet));
il.Emit(Codes.Unbox(result.Type));
il.Emit(Codes.Store(result));
}
il.Emit(Codes.Leave(leave));
il.Mark(proceed);
}
}
}
if (needsMethodArgs && needsMethodCopyArgs && arguments != null)
{
CopyArgumentArrayToParameters(weaver, arguments);
}
}
il.Position = leave;
if (hasMethod && needsCatch)
{
var exception = il.EmitLocal(Context.Finder.Exception);
il.Catch(exception);
for (int i = 0, count = mInterceptors.Length; i < count; i++)
{
var inc = mInterceptors[i];
var att = mAttributes[i];
if (att.HasRequiredMethod("OnException"))
{
il.Emit(Codes.ThisIf(inc));
il.Emit(Codes.Load(inc));
if (needsMethodArgs)
{
il.Emit(Codes.Load(mEventArgs));
}
else
{
il.Emit(Codes.Null);
}
il.Emit(Codes.Load(exception));
il.Emit(Codes.Invoke(Context.Finder.MethodInterceptorOnException));
}
}
if (needsExit || needsReturns)
{
il.Emit(Codes.Nop);
il.Emit(Codes.Leave(leave));
}
}
if (needsExit || needsReturns)
{
il.Finally(leave);
}
if (hasMethod)
{
if (result != null && needsMethodArgs)
{
il.Emit(Codes.Load(mEventArgs));
il.Emit(Codes.Load(result));
il.Emit(Codes.Box(weaver.Target.ReturnType));
il.Emit(Codes.Invoke(Context.Finder.MethodInterceptionArgsReturnSet));
}
if (needsExit)
{
for (int i = 0, count = mInterceptors.Length; i < count; i++)
{
var inc = mInterceptors[i];
var att = mAttributes[i];
if (att.HasRequiredMethod("OnExit"))
{
il.Emit(Codes.ThisIf(inc));
il.Emit(Codes.Load(inc));
if (needsMethodArgs)
{
il.Emit(Codes.Load(mEventArgs));
}
else
{
il.Emit(Codes.Null);
}
il.Emit(Codes.Invoke(Context.Finder.MethodInterceptorOnExit));
}
}
}
il.Mark(cancel);
}
if (hasReturn && needsReturns && result != null)
{
var rEventArgs = needsReturnsArgs ? il.EmitLocal(Context.Finder.MethodReturnInterceptionArgs) : null;
if (needsReturnsArgs)
{
il.Emit(method.IsStatic ? Codes.Null : Codes.This);
il.Emit(Codes.Load(result));
il.Emit(Codes.Box(result.Type));
il.Emit(Codes.Load(invocation));
il.Emit(Codes.Create(Context.Finder.MethodReturnInterceptionArgsCtor));
il.Emit(Codes.Store(rEventArgs));
}
for (int i = 0, count = rInterceptors.Length; i < count; i++)
{
var inc = rInterceptors[i];
var att = rAttributes[i];
if (att.HasRequiredMethod("OnReturn"))
{
il.Emit(Codes.ThisIf(inc));
il.Emit(Codes.Load(inc));
if (needsReturnsArgs)
{
il.Emit(Codes.Load(rEventArgs));
}
else
{
il.Emit(Codes.Null);
}
il.Emit(Codes.Invoke(Context.Finder.MethodReturnInterceptorOnReturn));
}
}
if (needsReturnsArgs)
{
il.Emit(Codes.Load(rEventArgs));
il.Emit(Codes.Invoke(Context.Finder.MethodReturnInterceptionArgsValueGet));
il.Emit(Codes.Unbox(result.Type));
il.Emit(Codes.Store(result));
}
}
if (!needsExit && !needsReturns)
{
il.Emit(Codes.Nop);
il.Emit(Codes.Leave(leave));
}
il.EndTry();
il.Insert = CodeInsertion.After;
if (hasMethod && arguments != null)
{
CopyArgumentArrayToReferences(weaver, arguments);
}
if (hasMethod && needsMethodArgs && result != null)
{
il.Emit(Codes.Nop);
il.Emit(Codes.Load(mEventArgs));
il.Emit(Codes.Invoke(Context.Finder.MethodInterceptionArgsReturnGet));
il.Emit(Codes.Unbox(weaver.Target.ReturnType));
}
else if (hasMethod && result != null)
{
il.Emit(Codes.Nop);
il.Emit(Codes.Load(result));
}
}
weaver.Body.InitLocals = true;
weaver.Body.OptimizeMacros();
}