PostSharp

[morphine]

Hi Gael,

I've been using PostSharp Laos for some time now, it's very cool! I'm trying to use it with log4net, to provide a way to easily log whatever is needed.

I've seen log4PostSharp, and I cannot use it for my purpose. Here's what I want to achieve:

• provide a configurable attribute at class level: LoggableContext (done)
• enforce the user to define 2 fields in that class: an log4net.ILog Log and a string LoggerName, both static; failure to comply yields compile-time errors (done)
• user has the possibility to define a DefaultLoggerName when applying attribute; see code below for example (done too)
• if and only if the DefaultLoggerName was set, I don't want the user to be able to set the field LoggerName, ever: for such an attempt a warning or an error should be issued; and this is where I need your help: is there any way to make this happen? (except for throwing exceptions at runtime...)

I guess I want to use PoshSharp for code analysis, eh?

Code: Select all

[LoggableContext(DefaultLoggerName="MyLogger")]
public class MyClass
{
   private static readonly ILog Log;
   public static readonly string LoggerName = "YourLogger";

   public void DoSomething()
   {
      Log.Info("Yeah yeah...doing some stuff.");
      // Log is not initialized in MyClass, as this is the job of the attribute, so this code will not fail
   }
}


Best,
Dan

[gfraiteur]

Wouldn't it be better to require the field LoggerName to be constant? So you would have the guarantee it is never updated...

[morphine]

Just tried; I'm using OnFieldAccessAspects and it looks like they don't work with constant fields...

Besides, I have the same requirement for Log: this one must never be initialized by user.

[gfraiteur]

Sure, OnFieldAccessAspects does not make sense with constant fields. But you can use a type-level aspect (like Compound) to verify all fields.

It's true it does not solve the problem of Log...

What you want is actually possible... using PostSharp Core. A "little" more difficult, however!

[morphine]

Yes, I am using CompoundAspect I must be on the right track then!

Hm..Core; I'll have a look at it one day. Thanks for the hint!

Btw: when using a MessageSource to display messages, I noticed Write method has these params:

Code: Select all

string locationFile, int locationLine, int locationColumn

I suppose I need to supply this data from PDB, right? The question is: does PostSharp have support for reading PDB files?

[gfraiteur]

It has, but in Core, not in Laos.