tal: support destructors with an extra argument.

[ccan] / ccan / tal / tal.h

diff --git a/ccan/tal/tal.h b/ccan/tal/tal.h
index af3943eebafec9b593e15a8fe5c951cc138a2481..200c2b161fc60916de8fb8954b27c293d2c0e84e 100644 (file)
--- a/ccan/tal/tal.h
+++ b/ccan/tal/tal.h
@@ -169,6 +169,53 @@ void *tal_free(const tal_t *p);
 #define tal_del_destructor(ptr, function)                                    \
        tal_del_destructor_((ptr), typesafe_cb(void, void *, (function), (ptr)))
 
+/**
+ * tal_add_destructor2 - add a 2-arg callback function when context is destroyed.
+ * @ptr: The tal allocated object.
+ * @function: the function to call before it's freed.
+ * @arg: the extra argument to the function.
+ *
+ * Sometimes an extra argument is required for a destructor; this
+ * saves the extra argument internally to avoid the caller having to
+ * do an extra allocation.
+ *
+ * Note that this can only fail if your allocfn fails and your errorfn returns.
+ */
+#define tal_add_destructor2(ptr, function, arg)                                \
+       tal_add_destructor2_((ptr),                                     \
+                            typesafe_cb_cast(void (*)(tal_t *, void *), \
+                                             void (*)(__typeof__(ptr), \
+                                                      __typeof__(arg)), \
+                                             (function)),              \
+                            (arg))
+
+/**
+ * tal_del_destructor - remove a destructor callback function.
+ * @ptr: The tal allocated object.
+ * @function: the function to call before it's freed.
+ *
+ * If @function has not been successfully added as a destructor, this returns
+ * false.
+ */
+#define tal_del_destructor(ptr, function)                                    \
+       tal_del_destructor_((ptr), typesafe_cb(void, void *, (function), (ptr)))
+
+/**
+ * tal_del_destructor2 - remove 2-arg callback function.
+ * @ptr: The tal allocated object.
+ * @function: the function to call before it's freed.
+ * @arg: the extra argument to the function.
+ *
+ * If @function has not been successfully added as a destructor with
+ * @arg, this returns false.
+ */
+#define tal_del_destructor2(ptr, function, arg)                                \
+       tal_del_destructor2_((ptr),                                     \
+                            typesafe_cb_cast(void (*)(tal_t *, void *), \
+                                             void (*)(__typeof__(ptr), \
+                                                      __typeof__(arg)), \
+                                             (function)),              \
+                            (arg))
 enum tal_notify_type {
        TAL_NOTIFY_FREE = 1,
        TAL_NOTIFY_STEAL = 2,
@@ -234,7 +281,8 @@ enum tal_notify_type {
        tal_del_notifier_((ptr),                                        \
                          typesafe_cb_postargs(void, void *, (callback), \
                                               (ptr),                   \
-                                              enum tal_notify_type, void *))
+                                              enum tal_notify_type, void *), \
+                         false, NULL)
 
 /**
  * tal_set_name - attach a name to a tal pointer.
@@ -449,12 +497,17 @@ bool tal_resize_(tal_t **ctxp, size_t size, size_t count, bool clear);
 bool tal_expand_(tal_t **ctxp, const void *src, size_t size, size_t count);
 
 bool tal_add_destructor_(const tal_t *ctx, void (*destroy)(void *me));
+bool tal_add_destructor2_(const tal_t *ctx, void (*destroy)(void *me, void *arg),
+                         void *arg);
 bool tal_del_destructor_(const tal_t *ctx, void (*destroy)(void *me));
+bool tal_del_destructor2_(const tal_t *ctx, void (*destroy)(void *me, void *arg),
+                         void *arg);
 
 bool tal_add_notifier_(const tal_t *ctx, enum tal_notify_type types,
                       void (*notify)(tal_t *ctx, enum tal_notify_type,
                                      void *info));
 bool tal_del_notifier_(const tal_t *ctx,
                       void (*notify)(tal_t *ctx, enum tal_notify_type,
-                                     void *info));
+                                     void *info),
+                      bool match_extra_arg, void *arg);
 #endif /* CCAN_TAL_H */