public void Inject()
{
var typeName = Guid.NewGuid().ToString("N");
var methodName = Guid.NewGuid().ToString("N");
AssemblyManager.Manage((assembly) =>
{
var traceAttributeCtor = assembly.MainModule.Import(
typeof(TraceAttribute).GetConstructor(Type.EmptyTypes));
var attribute = new CustomAttribute(traceAttributeCtor);
var type = AssemblyManager.AddType(assembly, typeName);
var method = AssemblyManager.AddMethod(type, methodName);
method.CustomAttributes.Add(attribute);
var processor = method.Body.GetILProcessor();
processor.Append(Instruction.Create(OpCodes.Ret));
}, (assembly) =>
{
var injector = new TraceAttribute();
var targetMethod = (from type in assembly.MainModule.GetAllTypes()
where type.Name == typeName
from method in type.Methods
where method.Name == methodName
select method).First();
Assert.AreEqual(1, targetMethod.Body.Instructions.Count);
injector.Inject(targetMethod);
var instructions = targetMethod.Body.Instructions;
Assert.AreEqual(12, instructions.Count);
Assert.AreEqual(OpCodes.Call, instructions[0].OpCode);
Assert.AreEqual(OpCodes.Callvirt, instructions[1].OpCode);
Assert.AreEqual(OpCodes.Stloc, instructions[2].OpCode);
Assert.AreEqual(OpCodes.Ldloc, instructions[3].OpCode);
Assert.AreEqual(OpCodes.Ldstr, instructions[4].OpCode);
Assert.AreEqual(OpCodes.Call, instructions[5].OpCode);
Assert.AreEqual(OpCodes.Call, instructions[6].OpCode);
Assert.AreEqual(OpCodes.Ldloc, instructions[7].OpCode);
Assert.AreEqual(OpCodes.Ldstr, instructions[8].OpCode);
Assert.AreEqual(OpCodes.Call, instructions[9].OpCode);
Assert.AreEqual(OpCodes.Call, instructions[10].OpCode);
Assert.AreEqual(OpCodes.Ret, instructions[11].OpCode);
}, false);
}
public void InjectWithThrowOpCode()
{
var typeName = Guid.NewGuid().ToString("N");
var methodName = Guid.NewGuid().ToString("N");
AssemblyManager.Manage((assembly) =>
{
var traceAttributeCtor = assembly.MainModule.Import(
typeof(TraceAttribute).GetConstructor(Type.EmptyTypes));
var attribute = new CustomAttribute(traceAttributeCtor);
var type = AssemblyManager.AddType(assembly, typeName);
var method = AssemblyManager.AddMethod(type, methodName,
new List <ParameterDefinition> {
new ParameterDefinition(assembly.MainModule.Import(typeof(bool)))
}, null);
method.CustomAttributes.Add(attribute);
var processor = method.Body.GetILProcessor();
var first = Instruction.Create(OpCodes.Ldarg_0);
processor.Append(first);
var argumentNullExceptionCtor = assembly.MainModule.Import(
typeof(ArgumentNullException).GetConstructor(new Type[] { typeof(string) }));
processor.Append(Instruction.Create(OpCodes.Ldstr, "error"));
processor.Append(Instruction.Create(OpCodes.Newobj, argumentNullExceptionCtor));
processor.Append(Instruction.Create(OpCodes.Throw));
var last = Instruction.Create(OpCodes.Ret);
processor.Append(last);
processor.InsertAfter(first, Instruction.Create(OpCodes.Brfalse_S, last));
}, (assembly) =>
{
var injector = new TraceAttribute();
var targetMethod = (from type in assembly.MainModule.GetAllTypes()
where type.Name == typeName
from method in type.Methods
where method.Name == methodName
select method).First();
Assert.AreEqual(6, targetMethod.Body.Instructions.Count);
injector.Inject(targetMethod);
Assert.AreEqual(21, targetMethod.Body.Instructions.Count);
var instructions = targetMethod.Body.Instructions;
Assert.AreEqual(OpCodes.Call, instructions[0].OpCode);
Assert.AreEqual(OpCodes.Callvirt, instructions[1].OpCode);
Assert.AreEqual(OpCodes.Stloc, instructions[2].OpCode);
Assert.AreEqual(OpCodes.Ldloc, instructions[3].OpCode);
Assert.AreEqual(OpCodes.Ldstr, instructions[4].OpCode);
Assert.AreEqual(OpCodes.Call, instructions[5].OpCode);
Assert.AreEqual(OpCodes.Call, instructions[6].OpCode);
Assert.AreEqual(OpCodes.Ldarg_0, instructions[7].OpCode);
Assert.AreEqual(OpCodes.Brfalse_S, instructions[8].OpCode);
Assert.AreEqual(OpCodes.Ldstr, instructions[9].OpCode);
Assert.AreEqual(OpCodes.Newobj, instructions[10].OpCode);
Assert.AreEqual(OpCodes.Ldloc, instructions[11].OpCode);
Assert.AreEqual(OpCodes.Ldstr, instructions[12].OpCode);
Assert.AreEqual(OpCodes.Call, instructions[13].OpCode);
Assert.AreEqual(OpCodes.Call, instructions[14].OpCode);
Assert.AreEqual(OpCodes.Throw, instructions[15].OpCode);
Assert.AreEqual(OpCodes.Ldloc, instructions[16].OpCode);
Assert.AreEqual(OpCodes.Ldstr, instructions[17].OpCode);
Assert.AreEqual(OpCodes.Call, instructions[18].OpCode);
Assert.AreEqual(OpCodes.Call, instructions[19].OpCode);
Assert.AreEqual(OpCodes.Ret, instructions[20].OpCode);
}, false);
}
