libpager: annotate objects managed by libports

Label _pager_class and provide a function which prints a
human-readable description of a pager object.

* libpager/pager-create.c (format_debug_info): New function.
(create_class): Label _pager_class.

1 files changed, 20 insertions, 0 deletions

diff --git a/libpager/pager-create.c b/libpager/pager-create.c
index b583f023..422e8f4e 100644
--- a/libpager/pager-create.c
+++ b/libpager/pager-create.c
@@ -15,6 +15,8 @@
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
 
+#include <stdio.h>
+
 #include "priv.h"
 
 /* Create and return a new pager with user info UPI.  */
@@ -50,6 +52,23 @@ pager_create (struct user_pager_info *upi,
   return p;
 }
 
+/* Provide a human-readable description of the given pager object.  */
+static error_t
+format_debug_info (const void *port, char *buffer, size_t size)
+{
+  const struct pager *pager = port;
+  const struct port_info *pi = port;
+
+  snprintf (buffer, size,
+	    "bucket: %s, class: %s, may_cache: %d",
+	    pi->bucket->label,
+	    pi->class->label,
+	    /* XXX I have no idea what might be interesting to print
+	       here, but it is straight forward to add stuff.  */
+	    pager->may_cache);
+
+  return 0;
+}
 
 /* This causes the function to be run at startup by compiler magic. */
 static void create_class (void) __attribute__ ((constructor));
@@ -58,5 +77,6 @@ static void
 create_class ()
 {
   _pager_class = ports_create_class (_pager_clean, _pager_real_dropweak);
+  ports_label_class (_pager_class, "_pager_class", format_debug_info);
   (void) &create_class;		/* Avoid warning */
 }