Changeset 33b6431b

Timestamp:

May 23, 2011, 10:24:49 PM (13 years ago)

Author:

David Benjamin <davidben@mit.edu>

Branches:

master, release-1.10, release-1.8, release-1.9

Children:

b848e30

Parents:

f97c1a6

git-author:

David Benjamin <davidben@mit.edu> (05/23/11 22:17:05)

git-committer:

David Benjamin <davidben@mit.edu> (05/23/11 22:24:49)

Message:

Clarify owl_io_dispatch ownership

A created owl_io_dispatch is owned by whoever created. For instances
where owl_select needs to remove one of them, we instead invalidate
them. In the case of perl IO dispatches, they are owned by the nebulous
blob that implicitly maps fd to IO dispatch. This is completely insane,
but should avoid leaving people with invalid owl_io_dispatch pointers.

Use this same mechanism to restore owl_select_prune_bad_fds logic.

We really need to kill this and owl_timer in favor of glib's things.

Files:

• owl.h (modified) (1 diff)
• select.c (modified) (11 diffs)

owl.h

@@ -548 +548 @@
   int fd;                                     /* FD to watch for dispatch. */
   int mode;
+  bool valid;
   int needs_gc;
   void (*callback)(const struct _owl_io_dispatch *, void *); /* C function to dispatch to. */

select.c

@@ -125 +125 @@
 };
 
-
-static const owl_io_dispatch *owl_select_find_io_dispatch_by_fd(const int fd)
+/* Returns the valid owl_io_dispatch for a given file descriptor. */
+static owl_io_dispatch *owl_select_find_valid_io_dispatch_by_fd(const int fd)
 {
   int i, len;
@@ -135 +135 @@
   for(i = 0; i < len; i++) {
     d = owl_list_get_element(dl, i);
-    if (d->fd == fd) return d;
+    if (d->fd == fd && d->valid) return d;
   }
   return NULL;
@@ -154 +154 @@
   }
   return -1;
+}
+
+static void owl_select_invalidate_io_dispatch(owl_io_dispatch *d)
+{
+  if (d == NULL || !d->valid)
+    return;
+  d->valid = false;
+  g_source_remove_poll(owl_io_dispatch_source, &d->pollfd);
 }
 
@@ -167 +175 @@
         d->needs_gc = 1;
       else {
+        owl_select_invalidate_io_dispatch(d);
         owl_list_remove_element(dl, elt);
         if (d->destroy)
           d->destroy(d);
-        g_source_remove_poll(owl_io_dispatch_source, &d->pollfd);
         g_free(d);
       }
@@ -195 +203 @@
 }
 
-/* Each FD may have at most one dispatcher.
+/* Each FD may have at most one valid dispatcher.
  * If a new dispatch is added for an FD, the old one is removed.
  * mode determines what types of events are watched for, and may be any combination of:
@@ -204 +212 @@
   owl_io_dispatch *d = g_new(owl_io_dispatch, 1);
   owl_list *dl = owl_global_get_io_dispatch_list(&g);
+  owl_io_dispatch *other;
 
   d->fd = fd;
+  d->valid = true;
   d->needs_gc = 0;
   d->mode = mode;
@@ -224 +234 @@
 
 
-  owl_select_remove_io_dispatch(owl_select_find_io_dispatch_by_fd(fd));
+  other = owl_select_find_valid_io_dispatch_by_fd(fd);
+  if (other)
+    owl_select_invalidate_io_dispatch(other);
   owl_list_append_element(dl, d);
 
@@ -242 +254 @@
   len = owl_list_get_size(dl);
   for(i = 0; i < len; i++) {
-    const owl_io_dispatch *d = owl_list_get_element(dl, i);
+    owl_io_dispatch *d = owl_list_get_element(dl, i);
+    if (!d->valid) continue;
+    if (d->pollfd.revents & G_IO_NVAL) {
+      owl_function_debugmsg("Pruning defunct dispatch on fd %d.", d->fd);
+      owl_select_invalidate_io_dispatch(d);
+    }
     if (d->pollfd.revents & d->pollfd.events)
       return TRUE;
@@ -258 +275 @@
   for (i = 0; i < len; i++) {
     owl_io_dispatch *d = owl_list_get_element(dl, i);
+    if (!d->valid) continue;
     if ((d->pollfd.revents & d->pollfd.events) && d->callback != NULL) {
       d->callback(d, d->data);
@@ -277 +295 @@
 int owl_select_add_perl_io_dispatch(int fd, int mode, SV *cb)
 {
-  const owl_io_dispatch *d = owl_select_find_io_dispatch_by_fd(fd);
+  const owl_io_dispatch *d = owl_select_find_valid_io_dispatch_by_fd(fd);
   if (d != NULL && d->callback != owl_perlconfig_io_dispatch) {
     /* Don't mess with non-perl dispatch functions from here. */
     return 1;
   }
+  /* Also remove any invalidated perl dispatch functions that may have
+   * stuck around. */
+  owl_select_remove_perl_io_dispatch(fd);
   owl_select_add_io_dispatch(fd, mode, owl_perlconfig_io_dispatch, owl_perlconfig_io_dispatch_destroy, cb);
   return 0;
 }
 
+static owl_io_dispatch *owl_select_find_perl_io_dispatch(int fd)
+{
+  int i, len;
+  const owl_list *dl;
+  owl_io_dispatch *d;
+  dl = owl_global_get_io_dispatch_list(&g);
+  len = owl_list_get_size(dl);
+  for(i = 0; i < len; i++) {
+    d = owl_list_get_element(dl, i);
+    if (d->fd == fd && d->callback == owl_perlconfig_io_dispatch)
+      return d;
+  }
+  return NULL;
+}
+
 int owl_select_remove_perl_io_dispatch(int fd)
 {
-  const owl_io_dispatch *d = owl_select_find_io_dispatch_by_fd(fd);
-  if (d != NULL && d->callback == owl_perlconfig_io_dispatch) {
+  owl_io_dispatch *d = owl_select_find_perl_io_dispatch(fd);
+  if (d != NULL) {
     /* Only remove perl io dispatchers from here. */
     owl_select_remove_io_dispatch(d);
@@ -320 +356 @@
   }
 }
-
-#if 0
-/* FIXME: Reimplement this check in the glib world. */
-static void owl_select_prune_bad_fds(void) {
-  owl_list *dl = owl_global_get_io_dispatch_list(&g);
-  int len, i;
-  struct stat st;
-  owl_io_dispatch *d;
-
-  len = owl_list_get_size(dl);
-  for (i = 0; i < len; i++) {
-    d = owl_list_get_element(dl, i);
-    if (fstat(d->fd, &st) < 0 && errno == EBADF) {
-      owl_function_debugmsg("Pruning defunct dispatch on fd %d.", d->fd);
-      d->needs_gc = 1;
-    }
-  }
-  owl_select_io_dispatch_gc();
-}
-#endif
 
 typedef struct _owl_task { /*noproto*/