/// <summary>
/// Emits an implementation of a given method.
/// </summary>
/// <param name="invocationContext">The InvocationContext for this call.</param>
/// <param name="eventId">The next eventID to use.</param>
/// <param name="autoKeyword">The auto-keyword to use if enabled.</param>
/// <returns>The method that is implemented.</returns>
private MethodBuilder EmitMethodImpl(InvocationContext invocationContext, ref int eventId, EventKeywords autoKeyword)
{
// get the method we are implementing and the parameter mapping
var interfaceMethod = invocationContext.MethodInfo;
var parameterMapping = _traceParameterProvider.ProvideParameterMapping(invocationContext.MethodInfo).Where(p => p.HasSource).ToList();
// if we are implementing an interface, then add an string context parameter
if (SupportsContext(invocationContext))
{
parameterMapping.Add(new ParameterMapping(Context));
}
// calculate the method name
// if there is more than one method with the given name, then append an ID to it
var methodName = interfaceMethod.Name;
var matchingMethods = interfaceMethod.DeclaringType.GetMethods().AsEnumerable().Where(im => String.Compare(im.Name, methodName, StringComparison.OrdinalIgnoreCase) == 0).ToArray();
if (matchingMethods.Length > 1)
{
methodName += "_" + Array.IndexOf(matchingMethods, interfaceMethod).ToString(CultureInfo.InvariantCulture);
}
// determine if this is a non-event or an event
// if an event, but there is no event attribute, just add one to the last event id
EventAttribute eventAttribute = null;
if (interfaceMethod.GetCustomAttribute <NonEventAttribute>() == null)
{
eventAttribute = _eventAttributeProvider.GetEventAttribute(invocationContext, eventId);
eventId = Math.Max(eventId, eventAttribute.EventId + 1);
}
// if auto-keywords are enabled, use them
if (eventAttribute != null && eventAttribute.Keywords == EventKeywords.None)
{
eventAttribute.Keywords = autoKeyword;
}
// create the internal method that calls WriteEvent
// this cannot be virtual or static, or the manifest builder will skip it
// it also cannot return a value
MethodBuilder m = _typeBuilder.DefineMethod(methodName, MethodAttributes.Public, typeof(void), parameterMapping.Select(p => p.CleanTargetType).ToArray());
// copy the Event or NonEvent attribute from the interface
if (eventAttribute != null)
{
m.SetCustomAttribute(EventAttributeHelper.ConvertEventAttributeToAttributeBuilder(eventAttribute));
}
else
{
m.SetCustomAttribute(EventAttributeHelper.CreateNonEventAttribute());
}
// add the parameter names
for (int i = 0; i < parameterMapping.Count; i++)
{
var parameter = parameterMapping[i];
m.DefineParameter(i + 1, ParameterAttributes.In, parameter.Name);
}
if (interfaceMethod.IsAbstract || !interfaceMethod.DeclaringType.IsSubclassOf(typeof(EventSource)))
{
// for interface methods, implement a call to write event
ProxyHelper.EmitDefaultValue(m.GetILGenerator(), m.ReturnType);
if (EmitIsEnabled(m, eventAttribute))
{
EmitCallWriteEvent(invocationContext, m, eventAttribute, parameterMapping);
}
// since EventSource only accepts non-virtual methods, and we need a virtual method to implement the abstract method
// we need to implement a wrapper method on the interface that calls into the base method
// and handles the bundling/unbundling of parameters
MethodBuilder im = _typeBuilder.DefineMethod("_" + methodName, MethodAttributes.Public | MethodAttributes.Virtual);
ProxyHelper.CopyMethodSignature(interfaceMethod, im);
ProxyHelper.EmitDefaultValue(im.GetILGenerator(), im.ReturnType);
if (EmitIsEnabled(im, eventAttribute))
{
EmitDirectProxy(invocationContext, im, m, parameterMapping);
}
// if this is an interface, then tell the system to map our method to the interface implementation
if (interfaceMethod.IsAbstract)
{
_typeBuilder.DefineMethodOverride(im, interfaceMethod);
}
}
else
{
// we are implementing a non-abstract method in event source, then
// all we can do is call the base implementation
EmitDirectProxy(invocationContext, m, interfaceMethod, parameterMapping);
}
return(m);
}
/// <summary>
/// Emits the implementation of a given interface method.
/// </summary>
/// <param name="executeMethod">The execute method to implement.</param>
private void EmitMethodImpl(MethodInfo executeMethod, List <Tuple <FieldInfo, object> > valuesToSet)
{
/*
* public TReturn Method (params)
* {
* var scope = new EventActivityScope(true);
* try
* {
* _log.Method(params);
* object value = _execute.Method(params);
* _log.Method_Completed(value);
* }
* catch (Exception e)
* {
* _log.Method_Faulted(e);
* throw;
* }
* finally
* {
* scope.Dispose();
* }
* }
*/
var invocationContext = new InvocationContext(executeMethod, InvocationContextTypes.MethodCall);
// start building the interface
MethodBuilder m = _typeBuilder.DefineMethod(executeMethod.Name, MethodAttributes.Public | MethodAttributes.Virtual);
ProxyHelper.CopyMethodSignature(executeMethod, m);
var parameterTypes = executeMethod.GetParameters().Select(p => p.ParameterType).ToArray();
ILGenerator mIL = m.GetILGenerator();
// set up a place to hold the return value
LocalBuilder returnValue = null;
if (m.ReturnType != typeof(void))
{
returnValue = mIL.DeclareLocal(m.ReturnType);
}
// set up the activity scope
LocalBuilder scope = null;
if (_callWithActivityScope)
{
scope = mIL.DeclareLocal(typeof(EventActivityScope));
mIL.Emit(OpCodes.Ldc_I4_1);
mIL.Emit(OpCodes.Newobj, typeof(EventActivityScope).GetConstructor(new Type[] { typeof(bool) }));
mIL.Emit(OpCodes.Stloc, scope);
}
// start the try block
mIL.BeginExceptionBlock();
// call the method on the log that matches the execute method
var targetParameterTypes = parameterTypes.Select(p => p.IsGenericParameter ? TypeImplementer.GetTypeSupportedByEventSource(p) : p).ToArray();
var logMethod = DiscoverMethod(_logField.FieldType, executeMethod.Name, String.Empty, targetParameterTypes);
if (logMethod != null)
{
// call the log method and throw away the result if there is one
EmitBaseMethodCall(m, invocationContext, _logField, executeMethod, logMethod, valuesToSet);
if (logMethod.ReturnType != typeof(void))
{
mIL.Emit(OpCodes.Pop);
}
}
// call execute
EmitBaseMethodCall(m, invocationContext, _executeField, executeMethod, executeMethod, valuesToSet);
if (executeMethod.ReturnType != typeof(void))
{
mIL.Emit(OpCodes.Stloc, returnValue);
}
// if there is a completed method, then call that
var completedParameterTypes = (executeMethod.ReturnType == typeof(void)) ? Type.EmptyTypes : new Type[] { executeMethod.ReturnType };
var completedMethod = DiscoverMethod(_logField.FieldType, executeMethod.Name, TypeImplementer.CompletedSuffix, completedParameterTypes);
if (completedMethod != null)
{
// load this._log
mIL.Emit(OpCodes.Ldarg_0);
mIL.Emit(OpCodes.Ldfld, _logField);
// load the value from the local variable
if (executeMethod.ReturnType != typeof(void))
{
mIL.Emit(OpCodes.Ldloc, returnValue);
}
mIL.Emit(OpCodes.Call, completedMethod);
if (completedMethod.ReturnType != typeof(void))
{
mIL.Emit(OpCodes.Pop);
}
}
// handle exceptions by logging them and rethrowing
mIL.BeginCatchBlock(typeof(Exception));
var faultedMethod = DiscoverMethod(_logField.FieldType, executeMethod.Name, TypeImplementer.FaultedSuffix, new Type[] { typeof(Exception) });
if (faultedMethod != null)
{
// save the exception
var exception = mIL.DeclareLocal(typeof(Exception));
mIL.Emit(OpCodes.Stloc, exception);
// load this._log
mIL.Emit(OpCodes.Ldarg_0);
mIL.Emit(OpCodes.Ldfld, _logField);
// load the exception
mIL.Emit(OpCodes.Ldloc, exception);
// call the fault handler
mIL.Emit(OpCodes.Call, faultedMethod);
if (faultedMethod.ReturnType != typeof(void))
{
mIL.Emit(OpCodes.Pop);
}
}
mIL.Emit(OpCodes.Rethrow);
// clean up the activity scope
if (_callWithActivityScope)
{
mIL.BeginFinallyBlock();
mIL.Emit(OpCodes.Ldloc, scope);
mIL.Emit(OpCodes.Callvirt, typeof(EventActivityScope).GetMethod("Dispose"));
}
mIL.EndExceptionBlock();
// return the result
if (executeMethod.ReturnType != typeof(void))
{
mIL.Emit(OpCodes.Ldloc, returnValue);
}
mIL.Emit(OpCodes.Ret);
}