/// <summary>
/// Create an advice that runs before and after the advised method.
/// </summary>
/// <param name="linq">Linq</param>
/// <param name="advice">Delegate used to produce an expression of code to be invoked instaed of the advised method : Func(Expression = [expression of target instance of advised method call], IEnumerable(Expression) = [enumerable of expression of argument used to call advised method], Expression = [expression of advised method body]) return an expression to invoke instead of the advised method</param>
/// <returns>Advice</returns>
static public IAdvice Around(this Advisor.ILinq linq, Func <Expression, IEnumerable <Expression>, Expression, Expression> advice)
{
return(new Advice((_Method, _Pointer) =>
{
var _type = _Method.Type();
var _signature = _Method.Signature();
var _parameters = new Collection <ParameterExpression>(_signature.Select(_Type => Expression.Parameter(_Type)).ToArray());
var _method = new DynamicMethod(string.Empty, _type, _signature, _Method.DeclaringType, true);
var _body = _method.GetILGenerator();
_body.Emit(_signature, false);
_body.Emit(_Pointer, _type, _signature);
_body.Emit(OpCodes.Ret);
var _advice = _signature.Instance == null ? advice(null, _parameters, Expression.Call(_method, _parameters)) : advice(_parameters[0], _parameters.Skip(1), Expression.Call(_method, _parameters));
if (_advice == null)
{
return null;
}
_method = new DynamicMethod(string.Empty, _type, _signature, _Method.DeclaringType, true);
_body = _method.GetILGenerator();
_body.Emit(_signature, false);
_body.Emit(OpCodes.Call, Expression.Lambda(_advice, _parameters).CompileToMethod());
_body.Emit(OpCodes.Ret);
_method.Prepare();
return _method;
}));
}
/// <summary>
/// Create an advice that runs after the advised method regardless of its outcome.
/// </summary>
/// <param name="linq">Linq</param>
/// <param name="advice">Delegate used to produce an expression of code to be invoked after the advised method : Func(Expression = [expression of target instance of advised method call], IEnumerable(Expression) = [enumerable of expression of argument used to call advised method]) return an expression(void) of code to invoke after the advised method</param>
/// <returns>Advice</returns>
static public IAdvice After(this Advisor.ILinq linq, Func <Expression, IEnumerable <Expression>, Expression> advice)
{
return(new Advice((_Method, _Pointer) =>
{
var _signature = _Method.Signature();
var _parameters = new Collection <ParameterExpression>(_signature.Select(_Type => Expression.Parameter(_Type)).ToArray());
var _advice = _signature.Instance == null ? advice(null, _parameters) : advice(_parameters[0], _parameters.Skip(1));
if (_advice == null)
{
return null;
}
if (_advice.Type != Metadata.Void)
{
throw new NotSupportedException();
}
var _type = _Method.ReturnType();
var _method = new DynamicMethod(string.Empty, _type, _signature, _Method.DeclaringType, true);
var _body = _method.GetILGenerator();
if (_type == Metadata.Void)
{
_body.BeginExceptionBlock();
_body.Emit(_signature, false);
_body.Emit(_Pointer, _type, _signature);
_body.BeginFinallyBlock();
_body.Emit(_signature, false);
_body.Emit(OpCodes.Call, Expression.Lambda(_advice, _parameters).CompileToMethod());
_body.EndExceptionBlock();
}
else
{
_body.DeclareLocal(_type);
_body.BeginExceptionBlock();
_body.Emit(_signature, false);
_body.Emit(_Pointer, _type, _signature);
_body.Emit(OpCodes.Stloc_0);
_body.BeginFinallyBlock();
_body.Emit(_signature, false);
_body.Emit(OpCodes.Call, Expression.Lambda(_advice, _parameters).CompileToMethod());
_body.EndExceptionBlock();
_body.Emit(OpCodes.Ldloc_0);
}
_body.Emit(OpCodes.Ret);
_method.Prepare();
return _method;
}));
}
/// <summary>
/// Create an advice that runs after the advised method regardless of its outcome.
/// </summary>
/// <param name="linq">Linq</param>
/// <param name="advice"></param>
/// <returns>Advice</returns>
static public IAdvice After(this Advisor.ILinq linq, Expression advice)
{
return(new Advice((_Method, _Pointer) =>
{
var _signature = _Method.Signature();
if (advice == null)
{
return null;
}
if (advice.Type != Metadata.Void)
{
throw new NotSupportedException();
}
var _type = _Method.ReturnType();
var _method = new DynamicMethod(string.Empty, _type, _signature, _Method.DeclaringType, true);
var _body = _method.GetILGenerator();
if (_type == Metadata.Void)
{
_body.BeginExceptionBlock();
_body.Emit(_signature, false);
_body.Emit(_Pointer, _type, _signature);
_body.BeginFinallyBlock();
_body.Emit(OpCodes.Call, Expression.Lambda(advice).CompileToMethod());
_body.EndExceptionBlock();
}
else
{
_body.DeclareLocal(_type);
_body.BeginExceptionBlock();
_body.Emit(_signature, false);
_body.Emit(_Pointer, _type, _signature);
_body.Emit(OpCodes.Stloc_0);
_body.BeginFinallyBlock();
_body.Emit(OpCodes.Call, Expression.Lambda(advice).CompileToMethod());
_body.EndExceptionBlock();
_body.Emit(OpCodes.Ldloc_0);
}
_body.Emit(OpCodes.Ret);
_method.Prepare();
return _method;
}));
}
/// <summary>
/// Create an advice that runs before the advised method.
/// </summary>
/// <param name="linq">Linq</param>
/// <param name="advice">Expression of code to be invoked before the advised method</param>
/// <returns>Advice</returns>
static public IAdvice Before(this Advisor.ILinq linq, Expression advice)
{
return(new Advice((_Method, _Pointer) =>
{
var _signature = _Method.Signature();
if (advice == null)
{
return null;
}
var _type = _Method.ReturnType();
var _method = new DynamicMethod(string.Empty, _type, _signature, _Method.DeclaringType, true);
var _body = _method.GetILGenerator();
_body.Emit(OpCodes.Call, Expression.Lambda(advice).CompileToMethod());
_body.Emit(_signature, false);
_body.Emit(_Pointer, _type, _signature);
_body.Emit(OpCodes.Ret);
_method.Prepare();
return _method;
}));
}
/// <summary>
/// After
/// </summary>
/// <param name="linq">Linq</param>
/// <returns>After</returns>
static public Advisor.Linq.IAfter After(this Advisor.ILinq linq)
{
return(null);
}