tal: support destructors with an extra argument.

[ccan] / ccan / tal / tal.c

diff --git a/ccan/tal/tal.c b/ccan/tal/tal.c
index 866f263ba871f7e2ca4cb430bc9a790f1637b941..2a2eca77c04f5bbd37cc35e4ee4c4507e17ec33a 100644 (file)
--- a/ccan/tal/tal.c
+++ b/ccan/tal/tal.c
@@ -14,6 +14,7 @@
 //#define TAL_DEBUG 1
 
 #define NOTIFY_IS_DESTRUCTOR 512
+#define NOTIFY_EXTRA_ARG 1024
 
 /* 32-bit type field, first byte 0 in either endianness. */
 enum prop_type {
@@ -56,9 +57,18 @@ struct notifier {
        union {
                void (*notifyfn)(tal_t *, enum tal_notify_type, void *);
                void (*destroy)(tal_t *); /* If NOTIFY_IS_DESTRUCTOR set */
+               void (*destroy2)(tal_t *, void *); /* If NOTIFY_EXTRA_ARG */
        } u;
 };
 
+/* Extra arg */
+struct notifier_extra_arg {
+       struct notifier n;
+       void *arg;
+};
+
+#define EXTRA_ARG(n) (((struct notifier_extra_arg *)(n))->arg)
+
 static struct {
        struct tal_hdr hdr;
        struct children c;
@@ -218,9 +228,13 @@ static void notify(const struct tal_hdr *ctx,
                n = (struct notifier *)p;
                if (n->types & type) {
                        errno = saved_errno;
-                       if (n->types & NOTIFY_IS_DESTRUCTOR)
-                               n->u.destroy(from_tal_hdr(ctx));
-                       else
+                       if (n->types & NOTIFY_IS_DESTRUCTOR) {
+                               if (n->types & NOTIFY_EXTRA_ARG)
+                                       n->u.destroy2(from_tal_hdr(ctx),
+                                                     EXTRA_ARG(n));
+                               else
+                                       n->u.destroy(from_tal_hdr(ctx));
+                       } else
                                n->u.notifyfn(from_tal_hdr(ctx), type,
                                              (void *)info);
                }
@@ -276,13 +290,22 @@ static struct notifier *add_notifier_property(struct tal_hdr *t,
                                              enum tal_notify_type types,
                                              void (*fn)(void *,
                                                         enum tal_notify_type,
-                                                        void *))
+                                                        void *),
+                                             void *extra_arg)
 {
-       struct notifier *prop = allocate(sizeof(*prop));
+       struct notifier *prop;
+
+       if (types & NOTIFY_EXTRA_ARG)
+               prop = allocate(sizeof(struct notifier_extra_arg));
+       else
+               prop = allocate(sizeof(struct notifier));
+
        if (prop) {
                init_property(&prop->hdr, t, NOTIFIER);
                prop->types = types;
                prop->u.notifyfn = fn;
+               if (types & NOTIFY_EXTRA_ARG)
+                       EXTRA_ARG(prop) = extra_arg;
        }
        return prop;
 }
@@ -290,24 +313,33 @@ static struct notifier *add_notifier_property(struct tal_hdr *t,
 static enum tal_notify_type del_notifier_property(struct tal_hdr *t,
                                                  void (*fn)(tal_t *,
                                                             enum tal_notify_type,
-                                                            void *))
+                                                            void *),
+                                                 bool match_extra_arg,
+                                                 void *extra_arg)
 {
         struct prop_hdr **p;
 
         for (p = (struct prop_hdr **)&t->prop; *p; p = &(*p)->next) {
                struct notifier *n;
+               enum tal_notify_type types;
 
                 if (is_literal(*p))
                        break;
                 if ((*p)->type != NOTIFIER)
                        continue;
                n = (struct notifier *)*p;
-               if (n->u.notifyfn == fn) {
-                       enum tal_notify_type types = n->types;
-                       *p = (*p)->next;
-                       freefn(n);
-                       return types & ~NOTIFY_IS_DESTRUCTOR;
-               }
+               if (n->u.notifyfn != fn)
+                       continue;
+
+               types = n->types;
+               if ((types & NOTIFY_EXTRA_ARG)
+                   && match_extra_arg
+                   && extra_arg != EXTRA_ARG(n))
+                       continue;
+
+               *p = (*p)->next;
+               freefn(n);
+               return types & ~(NOTIFY_IS_DESTRUCTOR|NOTIFY_EXTRA_ARG);
         }
         return 0;
 }
@@ -506,9 +538,19 @@ bool tal_add_destructor_(const tal_t *ctx, void (*destroy)(void *me))
 {
        tal_t *t = debug_tal(to_tal_hdr(ctx));
        return add_notifier_property(t, TAL_NOTIFY_FREE|NOTIFY_IS_DESTRUCTOR,
-                                    (void *)destroy);
+                                    (void *)destroy, NULL);
+}
+
+bool tal_add_destructor2_(const tal_t *ctx, void (*destroy)(void *me, void *arg),
+                         void *arg)
+{
+       tal_t *t = debug_tal(to_tal_hdr(ctx));
+       return add_notifier_property(t, TAL_NOTIFY_FREE|NOTIFY_IS_DESTRUCTOR
+                                    |NOTIFY_EXTRA_ARG,
+                                    (void *)destroy, arg);
 }
 
+/* We could support notifiers with an extra arg, but we didn't add to API */
 bool tal_add_notifier_(const tal_t *ctx, enum tal_notify_type types,
                       void (*callback)(tal_t *, enum tal_notify_type, void *))
 {
@@ -523,7 +565,7 @@ bool tal_add_notifier_(const tal_t *ctx, enum tal_notify_type types,
                          | TAL_NOTIFY_DEL_NOTIFIER)) == 0);
 
        /* Don't call notifier about itself: set types after! */
-        n = add_notifier_property(t, 0, callback);
+        n = add_notifier_property(t, 0, callback, NULL);
        if (unlikely(!n))
                return false;
 
@@ -537,12 +579,13 @@ bool tal_add_notifier_(const tal_t *ctx, enum tal_notify_type types,
 }
 
 bool tal_del_notifier_(const tal_t *ctx,
-                      void (*callback)(tal_t *, enum tal_notify_type, void *))
+                      void (*callback)(tal_t *, enum tal_notify_type, void *),
+                      bool match_extra_arg, void *extra_arg)
 {
        struct tal_hdr *t = debug_tal(to_tal_hdr(ctx));
        enum tal_notify_type types;
 
-        types = del_notifier_property(t, callback);
+        types = del_notifier_property(t, callback, match_extra_arg, extra_arg);
        if (types) {
                notify(t, TAL_NOTIFY_DEL_NOTIFIER, callback, 0);
                if (types != TAL_NOTIFY_FREE)
@@ -554,7 +597,13 @@ bool tal_del_notifier_(const tal_t *ctx,
 
 bool tal_del_destructor_(const tal_t *ctx, void (*destroy)(void *me))
 {
-       return tal_del_notifier_(ctx, (void *)destroy);
+       return tal_del_notifier_(ctx, (void *)destroy, false, NULL);
+}
+
+bool tal_del_destructor2_(const tal_t *ctx, void (*destroy)(void *me, void *arg),
+                         void *arg)
+{
+       return tal_del_notifier_(ctx, (void *)destroy, true, arg);
 }
 
 bool tal_set_name_(tal_t *ctx, const char *name, bool literal)