Re: [patch] Multiple/Java thread support

[Owen Taylor <otaylor redhat com>]

Paul Fisher <rao@gnu.org> writes:

> I've uploaded gtk-rao-980910-0.patch.gz to incoming.  The patch is
> against the CVS tree as of approximately 11:00AM EDT.  If anyone would
> like a patch for gtk+-1.1.1, please send me an email.
> 
> README:
> 
> Multiple Thread Library Support + Java Thread Support
> 
> GTK's current threading primitives are hardcoded for pthreads.  The
> GNU Classpath Project (http://www.classpath.org) is writing a Java AWT
> implementation using GTK+.  As such, we needed to make gdkthreads work
> with the threading facilities provided by the Java Virtual Machine.
> As opposed to adding the ability to compile GTK for either pthreads or
> JNI (java) threads, I went ahead and extended GTK's threading
> primitives to easily switch between different thread implementations
> based on the application using libgtk.  It should now be trivial to
> add new thread library support -- such as cthreads or Sun threads.

This looks neat. However, I'm pretty sure that it is the wrong
approach. Do we need to configure GTK+ with

 ./configure --with-java-threads --with-python-threads --with-guile-threads
             --with-pthreads

I think there is a serious scalability problem with that.

Rather, the right thing is to rather do something like:

 typedef struct _GdkThreadFuncs {
   void (*enter) (void);
   void (*leave) (void);
   void (*wake)  (void);
   void (*select)([whatever]);
 }
 
 GdkThreadFuncs *gdk_threads_set_funcs (GdkThreadFuncs *funcs);

I'm not completely sure this is the right level of abstraction,
perhaps it should be lower:

  gpointer (*create_mutex) (void);
  void     (*lock_mutex)   (gpointer mutex);
  void     (*unlock_mutex) (gpointer mutex);

But you get the idea -- new thread implementations should be
set at run time, not compile time. The argument given 
to --with-threads=pthreads, or whatever, just says which
a default thread mechanism should be compiled in.

Does this sound reasonable?
                                        Owen