]> git.ozlabs.org Git - ccan/blobdiff - ccan/tal/tal.c
tal: add tal_count() and length properties for arrays.
[ccan] / ccan / tal / tal.c
index 5ab6cb682cd5349b060b8731e99d9f18c45bb15e..c78185be01aa12715a0499088974ab8f561ccee6 100644 (file)
@@ -1,7 +1,6 @@
 /* Licensed under BSD-MIT - see LICENSE file for details */
 #include <ccan/tal/tal.h>
 #include <ccan/compiler/compiler.h>
-#include <ccan/hash/hash.h>
 #include <ccan/list/list.h>
 #include <ccan/take/take.h>
 #include <assert.h>
 
 //#define TAL_DEBUG 1
 
-/* How large should grouips get? */
-#define GROUP_NODE_AVERAGE 32
+#define NOTIFY_IS_DESTRUCTOR 512
 
 /* 32-bit type field, first byte 0 in either endianness. */
 enum prop_type {
        CHILDREN = 0x00c1d500,
-       GROUP = 0x00600d00,
-       DESTRUCTOR = 0x00de5700,
        NAME = 0x00111100,
+       NOTIFIER = 0x00071f00,
+       LENGTH = 0x00515300
 };
 
 struct tal_hdr {
-       struct tal_hdr *next;
+       struct list_node list;
        struct prop_hdr *prop;
+       struct children *parent_child;
 };
 
 struct prop_hdr {
@@ -35,25 +34,10 @@ struct prop_hdr {
        struct prop_hdr *next;
 };
 
-/* Unlike other properties, this is owned by parent, not child! */
-struct group {
-       struct prop_hdr hdr; /* GROUP */
-       struct list_head list; /* Head for child->group, node for others. */
-       /* We point to parent's children property, as it doesn't move! */
-       struct children *parent_child;
-       struct tal_hdr *first_child;
-};
-
 struct children {
        struct prop_hdr hdr; /* CHILDREN */
        struct tal_hdr *parent;
-       /* We always have one group.  Others may be added. */
-       struct group group;
-};
-
-struct destructor {
-       struct prop_hdr hdr; /* DESTRUCTOR */
-       void (*destroy)(void *me);
+       struct list_head children; /* Head of siblings. */
 };
 
 struct name {
@@ -61,16 +45,30 @@ struct name {
        char name[];
 };
 
+struct length {
+       struct prop_hdr hdr; /* LENGTH */
+       size_t count;
+};
+
+struct notifier {
+       struct prop_hdr hdr; /* NOTIFIER */
+       enum tal_notify_type types;
+       union {
+               void (*notifyfn)(tal_t *, enum tal_notify_type, void *);
+               void (*destroy)(tal_t *); /* If NOTIFY_IS_DESTRUCTOR set */
+       } u;
+};
+
 static struct {
        struct tal_hdr hdr;
        struct children c;
-} null_parent = { { NULL, &null_parent.c.hdr },
+} null_parent = { { { &null_parent.hdr.list, &null_parent.hdr.list },
+                   &null_parent.c.hdr, NULL },
                  { { CHILDREN, NULL },
                    &null_parent.hdr,
-                   { { GROUP, NULL },
-                     { { &null_parent.c.group.list.n,
-                         &null_parent.c.group.list.n } },
-                     &null_parent.c, NULL } }
+                   { { &null_parent.c.children.n,
+                       &null_parent.c.children.n } }
+                 }
 };
 
 
@@ -78,47 +76,37 @@ static void *(*allocfn)(size_t size) = malloc;
 static void *(*resizefn)(void *, size_t size) = realloc;
 static void (*freefn)(void *) = free;
 static void (*errorfn)(const char *msg) = (void *)abort;
+static bool initialized = false;
+/* Count on non-destrutor notifiers; often stays zero. */
+static size_t notifiers = 0;
 
 static inline void COLD call_error(const char *msg)
 {
        errorfn(msg);
 }
 
-static bool get_destroying_bit(struct tal_hdr *next)
+static bool get_destroying_bit(struct children *parent_child)
 {
-       return (size_t)next & 1;
+       return (size_t)parent_child & 1;
 }
 
-static void set_destroying_bit(struct tal_hdr **next)
+static void set_destroying_bit(struct children **parent_child)
 {
-       *next = (void *)((size_t)next | 1);
+       *parent_child = (void *)((size_t)*parent_child | 1);
 }
 
-static struct tal_hdr *ignore_destroying_bit(struct tal_hdr *next)
+static struct children *ignore_destroying_bit(struct children *parent_child)
 {
-       return (void *)((size_t)next & ~(size_t)1);
+       return (void *)((size_t)parent_child & ~(size_t)1);
 }
 
-static struct group *next_group(struct group *group)
-{
-       return list_entry(group->list.n.next, struct group, list.n);
-}
-
-static bool initialized = false;
-
 /* This means valgrind can see leaks. */
 static void tal_cleanup(void)
 {
-       struct group *i, *next;
+       struct tal_hdr *i;
 
-       /* Unlink null_parent. */
-       for (i = next_group(&null_parent.c.group);
-            i != &null_parent.c.group;
-            i = next) {
-               next = next_group(i);
-               freefn(i);
-       }
-       null_parent.c.group.first_child = NULL;
+       while ((i = list_top(&null_parent.c.children, struct tal_hdr, list)))
+               list_del(&i->list);
 
        /* Cleanup any taken pointers. */
        take_cleanup();
@@ -130,25 +118,34 @@ static void take_alloc_failed(const void *p)
        tal_free(p);
 }
 
+/* We carefully start all real properties with a zero byte. */
+static bool is_literal(const struct prop_hdr *prop)
+{
+       return ((char *)prop)[0] != 0;
+}
+
 #ifndef NDEBUG
 static const void *bounds_start, *bounds_end;
 
-static void update_bounds(const void *new)
+static void update_bounds(const void *new, size_t size)
 {
-       if (unlikely(!bounds_start))
-               bounds_start = bounds_end = new;
-       else if (new < bounds_start)
+       if (unlikely(!bounds_start)) {
                bounds_start = new;
-       else if (new > bounds_end)
-               bounds_end = new;
+               bounds_end = (char *)new + size;
+       } else if (new < bounds_start)
+               bounds_start = new;
+       else if ((char *)new + size > (char *)bounds_end)
+               bounds_end = (char *)new + size;
 }
 
 static bool in_bounds(const void *p)
 {
-       return !p || (p >= bounds_start && p <= bounds_end);
+       return !p
+               || (p >= (void *)&null_parent && p <= (void *)(&null_parent + 1))
+               || (p >= bounds_start && p <= bounds_end);
 }
 #else
-static void update_bounds(const void *new)
+static void update_bounds(const void *new, size_t size)
 {
 }
 
@@ -170,7 +167,11 @@ static struct tal_hdr *to_tal_hdr(const void *ctx)
 
        t = (struct tal_hdr *)((char *)ctx - sizeof(struct tal_hdr));
        check_bounds(t);
-       check_bounds(ignore_destroying_bit(t->next));
+       check_bounds(ignore_destroying_bit(t->parent_child));
+       check_bounds(t->list.next);
+       check_bounds(t->list.prev);
+       if (t->prop && !is_literal(t->prop))
+               check_bounds(t->prop);
        return t;
 }
 
@@ -181,9 +182,9 @@ static struct tal_hdr *to_tal_hdr_or_null(const void *ctx)
        return to_tal_hdr(ctx);
 }
 
-static void *from_tal_hdr(struct tal_hdr *hdr)
+static void *from_tal_hdr(const struct tal_hdr *hdr)
 {
-       return hdr + 1;
+       return (void *)(hdr + 1);
 }
 
 #ifdef TAL_DEBUG
@@ -206,30 +207,39 @@ static struct tal_hdr *debug_tal(struct tal_hdr *tal)
 }
 #endif
 
-static void *allocate(size_t size)
+static void notify(const struct tal_hdr *ctx,
+                  enum tal_notify_type type, const void *info)
 {
-       void *ret;
+        const struct prop_hdr *p;
 
-       /* Don't hand silly sizes to malloc. */
-       if (size >> (CHAR_BIT*sizeof(size) - 1)) {
-               call_error("allocation size overflow");
-               return NULL;
+        for (p = ctx->prop; p; p = p->next) {
+               struct notifier *n;
+
+                if (is_literal(p))
+                       break;
+                if (p->type != NOTIFIER)
+                       continue;
+               n = (struct notifier *)p;
+               if (n->types & type) {
+                       if (n->types & NOTIFY_IS_DESTRUCTOR)
+                               n->u.destroy(from_tal_hdr(ctx));
+                       else
+                               n->u.notifyfn(from_tal_hdr(ctx), type,
+                                             (void *)info);
+               }
        }
+}
 
-       ret = allocfn(size);
+static void *allocate(size_t size)
+{
+       void *ret = allocfn(size);
        if (!ret)
                call_error("allocation failed");
        else
-               update_bounds(ret);
+               update_bounds(ret, size);
        return ret;
 }
 
-/* We carefully start all real properties with a zero byte. */
-static bool is_literal(const struct prop_hdr *prop)
-{
-       return ((char *)prop)[0] != 0;
-}
-
 static struct prop_hdr **find_property_ptr(const struct tal_hdr *t,
                                           enum prop_type type)
 {
@@ -265,17 +275,46 @@ static void init_property(struct prop_hdr *hdr,
        parent->prop = hdr;
 }
 
-static struct destructor *add_destructor_property(struct tal_hdr *t,
-                                                 void (*destroy)(void *))
+static struct notifier *add_notifier_property(struct tal_hdr *t,
+                                             enum tal_notify_type types,
+                                             void (*fn)(void *,
+                                                        enum tal_notify_type,
+                                                        void *))
 {
-       struct destructor *prop = allocate(sizeof(*prop));
+       struct notifier *prop = allocate(sizeof(*prop));
        if (prop) {
-               init_property(&prop->hdr, t, DESTRUCTOR);
-               prop->destroy = destroy;
+               init_property(&prop->hdr, t, NOTIFIER);
+               prop->types = types;
+               prop->u.notifyfn = fn;
        }
        return prop;
 }
 
+static enum tal_notify_type del_notifier_property(struct tal_hdr *t,
+                                                 void (*fn)(tal_t *,
+                                                            enum tal_notify_type,
+                                                            void *))
+{
+        struct prop_hdr **p;
+
+        for (p = (struct prop_hdr **)&t->prop; *p; p = &(*p)->next) {
+               struct notifier *n;
+
+                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;
+               }
+        }
+        return 0;
+}
+
 static struct name *add_name_property(struct tal_hdr *t, const char *name)
 {
        struct name *prop;
@@ -288,13 +327,16 @@ static struct name *add_name_property(struct tal_hdr *t, const char *name)
        return prop;
 }
 
-static void init_group_property(struct group *group,
-                               struct children *parent_child,
-                               struct tal_hdr *child)
+static struct length *add_length_property(struct tal_hdr *t, size_t count)
 {
-       init_property(&group->hdr, child, GROUP);
-       group->parent_child = parent_child;
-       group->first_child = child;
+       struct length *prop;
+
+       prop = allocate(sizeof(*prop));
+       if (prop) {
+               init_property(&prop->hdr, t, LENGTH);
+               prop->count = count;
+       }
+       return prop;
 }
 
 static struct children *add_child_property(struct tal_hdr *parent,
@@ -304,129 +346,59 @@ static struct children *add_child_property(struct tal_hdr *parent,
        if (prop) {
                init_property(&prop->hdr, parent, CHILDREN);
                prop->parent = parent;
-
-               init_group_property(&prop->group, prop, child);
-               list_head_init(&prop->group.list);
-               update_bounds(&prop->group);
+               list_head_init(&prop->children);
        }
        return prop;
 }
 
-static struct group *add_group_property(struct tal_hdr *child,
-                                       struct children *parent_child)
-{
-       struct group *prop = allocate(sizeof(*prop));
-       if (prop)
-               init_group_property(prop, parent_child, child);
-       return prop;
-}
-
 static bool add_child(struct tal_hdr *parent, struct tal_hdr *child)
 {
-        struct group *group;
        struct children *children = find_property(parent, CHILDREN);
 
         if (!children) {
-               children = add_child_property(parent, child);
-               if (!children)
-                       return false;
-               list_head_init(&children->group.list);
-
-               /* Child links to itself. */
-                child->next = child;
-               return true;
-       }
-
-       /* Last one (may be children->group itself). */
-       group = next_group(&children->group);
-
-       /* Empty group can happen: null_parent, or all children freed. */
-       if (unlikely(!group->first_child)) {
-               assert(group == &children->group);
-               /* This hits on first child appended to null parent. */
                if (unlikely(!initialized)) {
                        atexit(tal_cleanup);
                        take_allocfail(take_alloc_failed);
                        initialized = true;
                }
-               /* Link group into this child, make it the first one. */
-               group->hdr.next = child->prop;
-               child->prop = &group->hdr;
-               group->first_child = child;
-
-               /* Child links to itself. */
-               child->next = child;
-               return true;
+               children = add_child_property(parent, child);
+               if (!children)
+                       return false;
        }
-
-       if (unlikely(hash_pointer(child, 0) % GROUP_NODE_AVERAGE == 0)) {
-               struct group *newgroup;
-
-               newgroup = add_group_property(child, children);
-               if (likely(newgroup)) {
-                       list_add(&children->group.list, &newgroup->list.n);
-
-                       /* Child links to itself. */
-                       child->next = child;
-                       return true;
-               }
-               /* Fall through: on allocation failure reuse old group. */
-        }
-
-       /* We insert after head, otherwise we'd need to find end. */
-       child->next = group->first_child->next;
-       group->first_child->next = child;
+       list_add(&children->children, &child->list);
+       child->parent_child = children;
        return true;
 }
 
-static void del_tree(struct tal_hdr *t)
+static void del_tree(struct tal_hdr *t, const tal_t *orig)
 {
        struct prop_hdr **prop, *p, *next;
 
         /* Already being destroyed?  Don't loop. */
-        if (unlikely(get_destroying_bit(t->next)))
+        if (unlikely(get_destroying_bit(t->parent_child)))
                 return;
 
-        set_destroying_bit(&t->next);
+        set_destroying_bit(&t->parent_child);
 
-        /* Carefully call destructors, removing as we go. */
-        while ((prop = find_property_ptr(t, DESTRUCTOR))) {
-               struct destructor *d = (struct destructor *)*prop;
-                d->destroy(from_tal_hdr(t));
-                *prop = d->hdr.next;
-               freefn(d);
-        }
+       /* Call free notifiers. */
+       notify(t, TAL_NOTIFY_FREE, (tal_t *)orig);
 
        /* Now free children and groups. */
        prop = find_property_ptr(t, CHILDREN);
        if (prop) {
+               struct tal_hdr *i;
                struct children *c = (struct children *)*prop;
-               struct group *group, *next;
-
-               group = &c->group;
-               do {
-                       next = next_group(group);
-                       if (group->first_child) {
-                               struct tal_hdr *i, *nextc;
-
-                               i = group->first_child;
-                               do {
-                                       nextc = i->next;
-                                       del_tree(i);
-                                       i = nextc;
-                               } while (i != group->first_child);
-                       }
-                       if (group != &c->group)
-                               freefn(group);
-                       group = next;
-               } while (group != &c->group);
+
+               while ((i = list_top(&c->children, struct tal_hdr, list))) {
+                       list_del(&i->list);
+                       del_tree(i, orig);
+               }
        }
 
-        /* Finally free our properties (groups are freed by parent). */
+        /* Finally free our properties. */
         for (p = t->prop; p && !is_literal(p); p = next) {
                 next = p->next;
-               if (p->type != GROUP)
-                       freefn(p);
+               freefn(p);
         }
         freefn(t);
 }
@@ -446,51 +418,42 @@ void *tal_alloc_(const tal_t *ctx, size_t size, bool clear, const char *label)
                return NULL;
        }
        debug_tal(parent);
+       if (notifiers)
+               notify(parent, TAL_NOTIFY_ADD_CHILD, from_tal_hdr(child));
        return from_tal_hdr(debug_tal(child));
 }
 
-/* Update back ptrs, etc, as required.
- * May return pointer to parent. */
-static struct tal_hdr *remove_node(struct tal_hdr *t)
+static bool adjust_size(size_t *size, size_t count)
 {
-        struct prop_hdr **prop;
-        struct tal_hdr *prev;
+       /* Multiplication wrap */
+        if (count && unlikely(*size * count / *size != count))
+               goto overflow;
 
-       /* Loop around to find previous node. */
-       for (prev = t->next; prev->next != t; prev = prev->next);
+        *size *= count;
 
-       /* Unlink ourselves. */
-       prev->next = t->next;
+        /* Make sure we don't wrap adding header. */
+        if (*size + sizeof(struct tal_hdr) < sizeof(struct tal_hdr))
+               goto overflow;
+       return true;
+overflow:
+       call_error("allocation size overflow");
+       return false;
+}
 
-       /* Are we the node with the group property? */
-       prop = find_property_ptr(t, GROUP);
-       if (prop) {
-               struct group *group = (struct group *)*prop;
-
-               /* Are we the only one? */
-               if (prev == t) {
-                       struct prop_hdr *next = (*prop)->next;
-                       struct children *c = group->parent_child;
-                       /* Is this the group embedded in the child property? */
-                       if (group == &c->group) {
-                               group->first_child = NULL;
-                       } else {
-                               /* Empty group, so free it. */
-                               list_del_from(&c->group.list, &group->list.n);
-                               freefn(group);
-                       }
-                       *prop = next;
-                       return c->parent;
-               } else {
-                       /* Move property to next node. */
-                       group->first_child = t->next;
-
-                       *prop = group->hdr.next;
-                       group->hdr.next = t->next->prop;
-                       t->next->prop = &group->hdr;
-               }
+void *tal_alloc_arr_(const tal_t *ctx, size_t size, size_t count, bool clear,
+                    bool add_count, const char *label)
+{
+       void *ret;
+
+       if (!adjust_size(&size, count))
+               return NULL;
+
+       ret = tal_alloc_(ctx, size, clear, label);
+       if (likely(ret) && add_count) {
+               if (unlikely(!add_length_property(to_tal_hdr(ret), count)))
+                       ret = tal_free(ret);
        }
-       return NULL;
+       return ret;
 }
 
 void *tal_free(const tal_t *ctx)
@@ -499,8 +462,11 @@ void *tal_free(const tal_t *ctx)
                struct tal_hdr *t;
                int saved_errno = errno;
                t = debug_tal(to_tal_hdr(ctx));
-               remove_node(t);
-               del_tree(t);
+               if (notifiers)
+                       notify(ignore_destroying_bit(t->parent_child)->parent,
+                              TAL_NOTIFY_DEL_CHILD, ctx);
+               list_del(&t->list);
+               del_tree(t, ctx);
                errno = saved_errno;
        }
        return NULL;
@@ -509,40 +475,82 @@ void *tal_free(const tal_t *ctx)
 void *tal_steal_(const tal_t *new_parent, const tal_t *ctx)
 {
         if (ctx) {
-               struct tal_hdr *newpar, *t, *old_next, *old_parent;
+               struct tal_hdr *newpar, *t, *old_parent;
 
                 newpar = debug_tal(to_tal_hdr_or_null(new_parent));
                 t = debug_tal(to_tal_hdr(ctx));
 
-               /* Save enough data to get us back if we fail! */
-               old_next = t->next;
-
                 /* Unlink it from old parent. */
-                old_parent = remove_node(t);
+               list_del(&t->list);
+               old_parent = ignore_destroying_bit(t->parent_child)->parent;
+
                 if (unlikely(!add_child(newpar, t))) {
-                       /* If we were last child, parent returned by
-                        * remove_node, otherwise search old siblings
-                        * for it. */
-                       if (!old_parent) {
-                               struct group *g;
-                               while (!(g = find_property(old_next, GROUP)))
-                                       old_next = old_next->next;
-                               old_parent = g->parent_child->parent;
-                       }
-                       /* We can always add to old parent, becuase it has one
-                        * group already. */
+                       /* We can always add to old parent, becuase it has a
+                        * children property already. */
                        if (!add_child(old_parent, t))
                                abort();
                        return NULL;
                }
                debug_tal(newpar);
+               if (notifiers)
+                       notify(t, TAL_NOTIFY_STEAL, new_parent);
         }
         return (void *)ctx;
 }
 
-bool tal_add_destructor_(tal_t *ctx, void (*destroy)(void *me))
+bool tal_add_destructor_(const tal_t *ctx, void (*destroy)(void *me))
 {
-        return add_destructor_property(debug_tal(to_tal_hdr(ctx)), destroy);
+       tal_t *t = debug_tal(to_tal_hdr(ctx));
+       return add_notifier_property(t, TAL_NOTIFY_FREE|NOTIFY_IS_DESTRUCTOR,
+                                    (void *)destroy);
+}
+
+bool tal_add_notifier_(const tal_t *ctx, enum tal_notify_type types,
+                      void (*callback)(tal_t *, enum tal_notify_type, void *))
+{
+       tal_t *t = debug_tal(to_tal_hdr(ctx));
+       struct notifier *n;
+
+       assert(types);
+       assert((types & ~(TAL_NOTIFY_FREE | TAL_NOTIFY_STEAL | TAL_NOTIFY_MOVE
+                         | TAL_NOTIFY_RESIZE | TAL_NOTIFY_RENAME
+                         | TAL_NOTIFY_ADD_CHILD | TAL_NOTIFY_DEL_CHILD
+                         | TAL_NOTIFY_ADD_NOTIFIER
+                         | TAL_NOTIFY_DEL_NOTIFIER)) == 0);
+
+       /* Don't call notifier about itself: set types after! */
+        n = add_notifier_property(t, 0, callback);
+       if (unlikely(!n))
+               return false;
+
+       if (notifiers)
+               notify(t, TAL_NOTIFY_ADD_NOTIFIER, callback);
+
+       n->types = types;
+       if (types != TAL_NOTIFY_FREE)
+               notifiers++;
+       return true;
+}
+
+bool tal_del_notifier_(const tal_t *ctx,
+                      void (*callback)(tal_t *, enum tal_notify_type, void *))
+{
+       struct tal_hdr *t = debug_tal(to_tal_hdr(ctx));
+       enum tal_notify_type types;
+
+        types = del_notifier_property(t, callback);
+       if (types) {
+               notify(t, TAL_NOTIFY_DEL_NOTIFIER, callback);
+               if (types != TAL_NOTIFY_FREE)
+                       notifiers--;
+               return true;
+       }
+       return false;
+}
+
+bool tal_del_destructor_(const tal_t *ctx, void (*destroy)(void *me))
+{
+       return tal_del_notifier_(ctx, (void *)destroy);
 }
 
 bool tal_set_name_(tal_t *ctx, const char *name, bool literal)
@@ -567,11 +575,12 @@ bool tal_set_name_(tal_t *ctx, const char *name, bool literal)
                 /* Append literal. */
                 for (p = &t->prop; *p && !is_literal(*p); p = &(*p)->next);
                 *p = (struct prop_hdr *)name;
-                return true;
-        }
-        if (!add_name_property(t, name))
+        } else if (!add_name_property(t, name))
                return false;
+
        debug_tal(t);
+       if (notifiers)
+               notify(t, TAL_NOTIFY_RENAME, name);
        return true;
 }
 
@@ -588,26 +597,26 @@ const char *tal_name(const tal_t *t)
        return n->name;
 }
 
+size_t tal_count(const tal_t *ptr)
+{
+       struct length *l;
+
+       l = find_property(debug_tal(to_tal_hdr(ptr)), LENGTH);
+       if (!l)
+               return 0;
+       return l->count;
+}
+
 /* Start one past first child: make stopping natural in circ. list. */
 static struct tal_hdr *first_child(struct tal_hdr *parent)
 {
        struct children *child;
-       struct group *group;
 
        child = find_property(parent, CHILDREN);
         if (!child)
                 return NULL;
 
-       /* Careful of empty group embedded in child property. */
-       if (child->group.first_child)
-               return child->group.first_child->next;
-
-       /* There could still be another group! */
-       group = next_group(&child->group);
-       if (group == &child->group)
-               return NULL;
-
-       return group->first_child->next;
+       return list_top(&child->children, struct tal_hdr, list);
 }
 
 tal_t *tal_first(const tal_t *root)
@@ -623,7 +632,6 @@ tal_t *tal_first(const tal_t *root)
 tal_t *tal_next(const tal_t *root, const tal_t *prev)
 {
         struct tal_hdr *c, *t = debug_tal(to_tal_hdr(prev)), *top;
-        struct group *group;
 
         /* Children? */
        c = first_child(t);
@@ -632,20 +640,17 @@ tal_t *tal_next(const tal_t *root, const tal_t *prev)
 
         top = to_tal_hdr_or_null(root);
         do {
-               struct group *next;
+               struct tal_hdr *next;
+               struct list_node *end;
 
-               /* Are we back to first child in group? */
-               group = find_property(t, GROUP);
-               if (!group)
-                        return from_tal_hdr(t->next);
+               end = &ignore_destroying_bit(t->parent_child)->children.n;
 
-               /* Last group is one inside children property. */
-               next = next_group(group);
-               if (next != &group->parent_child->group)
-                       return from_tal_hdr(next->first_child->next);
+               next = list_entry(t->list.next, struct tal_hdr, list);
+               if (&next->list != end)
+                       return from_tal_hdr(next);
 
                 /* OK, go back to parent. */
-                t = group->parent_child->parent;
+                t = ignore_destroying_bit(t->parent_child)->parent;
         } while (t != top);
 
         return NULL;
@@ -653,35 +658,27 @@ tal_t *tal_next(const tal_t *root, const tal_t *prev)
 
 tal_t *tal_parent(const tal_t *ctx)
 {
-        struct group *group;
         struct tal_hdr *t;
 
        if (!ctx)
                return NULL;
 
        t = debug_tal(to_tal_hdr(ctx));
-
-       while (!(group = find_property(t, GROUP)))
-               t = t->next;
-
-       if (group->parent_child->parent == &null_parent.hdr)
+       if (ignore_destroying_bit(t->parent_child)->parent == &null_parent.hdr)
                return NULL;
-        return from_tal_hdr(group->parent_child->parent);
+        return from_tal_hdr(ignore_destroying_bit(t->parent_child)->parent);
 }
 
-bool tal_resize_(tal_t **ctxp, size_t size)
+bool tal_resize_(tal_t **ctxp, size_t size, size_t count)
 {
-        struct tal_hdr *old_t, *t, **prev;
-        struct group *group;
+        struct tal_hdr *old_t, *t;
         struct children *child;
+       struct length *len;
 
         old_t = debug_tal(to_tal_hdr(*ctxp));
 
-       /* Don't hand silly sizes to realloc. */
-       if (size >> (CHAR_BIT*sizeof(size) - 1)) {
-               call_error("Reallocation size overflow");
+       if (!adjust_size(&size, count))
                return false;
-       }
 
         t = resizefn(old_t, size + sizeof(struct tal_hdr));
        if (!t) {
@@ -690,35 +687,37 @@ bool tal_resize_(tal_t **ctxp, size_t size)
        }
 
        /* If it didn't move, we're done! */
-        if (t == old_t)
-                return true;
-       update_bounds(t);
-
-       /* Fix up linked list pointer. */
-       for (prev = &t->next; *prev != old_t; prev = &(*prev)->next);
-       *prev = t;
-
-       /* Fix up group pointer, if any. */
-       group = find_property(t, GROUP);
-       if (group) {
-               assert(group->first_child == old_t);
-               group->first_child = t;
+        if (t != old_t) {
+               update_bounds(t, size + sizeof(struct tal_hdr));
+
+               /* Fix up linked list pointers. */
+               if (list_entry(t->list.next, struct tal_hdr, list) != old_t)
+                       t->list.next->prev = t->list.prev->next = &t->list;
+
+               /* Fix up child property's parent pointer. */
+               child = find_property(t, CHILDREN);
+               if (child) {
+                       assert(child->parent == old_t);
+                       child->parent = t;
+               }
+               *ctxp = from_tal_hdr(debug_tal(t));
+               if (notifiers)
+                       notify(t, TAL_NOTIFY_MOVE, from_tal_hdr(old_t));
        }
+       len = find_property(t, LENGTH);
+       if (len)
+               len->count = count;
+       if (notifiers)
+               notify(t, TAL_NOTIFY_RESIZE, (void *)size);
 
-       /* Fix up child propertie's parent pointer. */
-       child = find_property(t, CHILDREN);
-       if (child) {
-               assert(child->parent == old_t);
-               child->parent = t;
-       }
-       *ctxp = from_tal_hdr(debug_tal(t));
        return true;
 }
 
 char *tal_strdup(const tal_t *ctx, const char *p)
 {
        /* We have to let through NULL for take(). */
-       return tal_dup(ctx, char, p, p ? strlen(p) + 1: 1, 0);
+       return tal_dup_(ctx, p, 1, p ? strlen(p) + 1: 1, 0, false,
+                       TAL_LABEL(char, "[]"));
 }
 
 char *tal_strndup(const tal_t *ctx, const char *p, size_t n)
@@ -734,19 +733,27 @@ char *tal_strndup(const tal_t *ctx, const char *p, size_t n)
        } else
                len = n;
 
-       ret = tal_dup(ctx, char, p, len, 1);
+       ret = tal_dup_(ctx, p, 1, len, 1, false, TAL_LABEL(char, "[]"));
        if (ret)
                ret[len] = '\0';
        return ret;
 }
 
-void *tal_dup_(const tal_t *ctx, const void *p, size_t n, size_t extra,
+void *tal_dup_(const tal_t *ctx, const void *p, size_t size,
+              size_t n, size_t extra, bool add_count,
               const char *label)
 {
        void *ret;
+       size_t nbytes = size;
+
+       if (!adjust_size(&nbytes, n)) {
+               if (taken(p))
+                       tal_free(p);
+               return NULL;
+       }
 
-       /* Beware overflow! */
-       if (n + extra < n || n + extra + sizeof(struct tal_hdr) < n) {
+       /* Beware addition overflow! */
+       if (n + extra < n) {
                call_error("dup size overflow");
                if (taken(p))
                        tal_free(p);
@@ -756,15 +763,16 @@ void *tal_dup_(const tal_t *ctx, const void *p, size_t n, size_t extra,
        if (taken(p)) {
                if (unlikely(!p))
                        return NULL;
-               if (unlikely(!tal_resize_((void **)&p, n + extra)))
+               if (unlikely(!tal_resize_((void **)&p, size, n + extra)))
                        return tal_free(p);
                if (unlikely(!tal_steal(ctx, p)))
                        return tal_free(p);
                return (void *)p;
        }
-       ret = tal_alloc_(ctx, n + extra, false, label);
+
+       ret = tal_alloc_arr_(ctx, size, n + extra, false, add_count, label);
        if (ret)
-               memcpy(ret, p, n);
+               memcpy(ret, p, nbytes);
        return ret;
 }
 
@@ -834,10 +842,10 @@ static void dump_node(unsigned int indent, const struct tal_hdr *t)
                printf("  ");
        printf("%p", t);
         for (p = t->prop; p; p = p->next) {
-               struct group *g;
                struct children *c;
-               struct destructor *d;
                struct name *n;
+               struct notifier *no;
+               struct length *l;
                 if (is_literal(p)) {
                        printf(" \"%s\"", (const char *)p);
                        break;
@@ -845,27 +853,22 @@ static void dump_node(unsigned int indent, const struct tal_hdr *t)
                switch (p->type) {
                case CHILDREN:
                        c = (struct children *)p;
-                       printf(" CHILDREN(%p):parent=%p,group=%p\n",
-                              p, c->parent, &c->group);
-                       g = &c->group;
-                       printf("  GROUP(%p):list={%p,%p},parent_ch=%p,first=%p",
-                              g, g->list.n.next, g->list.n.next,
-                              g->parent_child, g->first_child);
-                       break;
-               case GROUP:
-                       g = (struct group *)p;
-                       printf(" GROUP(%p):list={%p,%p},,parent_ch=%p,first=%p",
-                              p, g->list.n.next, g->list.n.next,
-                              g->parent_child, g->first_child);
-                       break;
-               case DESTRUCTOR:
-                       d = (struct destructor *)p;
-                       printf(" DESTRUCTOR(%p):fn=%p", p, d->destroy);
+                       printf(" CHILDREN(%p):parent=%p,children={%p,%p}\n",
+                              p, c->parent,
+                              c->children.n.prev, c->children.n.next);
                        break;
                case NAME:
                        n = (struct name *)p;
                        printf(" NAME(%p):%s", p, n->name);
                        break;
+               case NOTIFIER:
+                       no = (struct notifier *)p;
+                       printf(" NOTIFIER(%p):fn=%p", p, no->u.notifyfn);
+                       break;
+               case LENGTH:
+                       l = (struct length *)p;
+                       printf(" LENGTH(%p):count=%zu", p, l->count);
+                       break;
                default:
                        printf(" **UNKNOWN(%p):%i**", p, p->type);
                }
@@ -876,27 +879,16 @@ static void dump_node(unsigned int indent, const struct tal_hdr *t)
 static void tal_dump_(unsigned int level, const struct tal_hdr *t)
 {
         struct children *children;
-       struct group *group;
 
        dump_node(level, t);
 
        children = find_property(t, CHILDREN);
-       if (!children)
-               return;
-
-       group = &children->group;
-       do {
+       if (children) {
                struct tal_hdr *i;
 
-               i = group->first_child;
-               if (i) {
-                       do {
-                               tal_dump_(level+1, i);
-                               i = i->next;
-                       } while (i != group->first_child);
-               }
-               group = next_group(group);
-       } while (group != &children->group);
+               list_for_each(&children->children, i, list)
+                       tal_dump_(level + 1, i);
+       }
 }
 
 void tal_dump(void)
@@ -918,20 +910,20 @@ static bool check_err(struct tal_hdr *t, const char *errorstr,
        return false;
 }
 
-static bool check_group(struct group *group,
-                       struct tal_hdr *t, const char *errorstr);
-
-static bool check_node(struct group *group,
+static bool check_node(struct children *parent_child,
                       struct tal_hdr *t, const char *errorstr)
 {
        struct prop_hdr *p;
        struct name *name = NULL;
        struct children *children = NULL;
-       struct group *gr = NULL;
+       struct length *length = NULL;
 
-       if (t != &null_parent.hdr && !in_bounds(t))
+       if (!in_bounds(t))
                return check_err(t, errorstr, "invalid pointer");
 
+       if (ignore_destroying_bit(t->parent_child) != parent_child)
+               return check_err(t, errorstr, "incorrect parent");
+
        for (p = t->prop; p; p = p->next) {
                if (is_literal(p)) {
                        if (name)
@@ -940,25 +932,24 @@ static bool check_node(struct group *group,
                        name = (struct name *)p;
                        break;
                }
-               if (p != &null_parent.c.hdr && p != &null_parent.c.group.hdr
-                   && !in_bounds(p))
+               if (!in_bounds(p))
                        return check_err(t, errorstr,
                                         "has bad property pointer");
 
                switch (p->type) {
-               case GROUP:
-                       if (gr)
-                               return check_err(t, errorstr,
-                                                "has two groups");
-                       gr = (struct group *)p;
-                       break;
                case CHILDREN:
                        if (children)
                                return check_err(t, errorstr,
                                                 "has two child nodes");
                        children = (struct children *)p;
                        break;
-               case DESTRUCTOR:
+               case LENGTH:
+                       if (length)
+                               return check_err(t, errorstr,
+                                                "has two lengths");
+                       length = (struct length *)p;
+                       break;
+               case NOTIFIER:
                        break;
                case NAME:
                        if (name)
@@ -970,40 +961,16 @@ static bool check_node(struct group *group,
                        return check_err(t, errorstr, "has unknown property");
                }
        }
-       if (group && gr != group)
-               return check_err(t, errorstr, "has bad group");
-
        if (children) {
-               if (!list_check(&children->group.list, errorstr))
-                       return false;
-               gr = &children->group;
-               do {
-                       if (gr->first_child) {
-                               if (!check_group(gr, gr->first_child, errorstr))
-                                       return false;
-                       } else if (gr != &children->group) {
-                               /* Empty groups should be deleted! */
-                               return check_err(t, errorstr,
-                                                "has empty group");
-                       }
-                       gr = next_group(gr);
-               } while (gr != &children->group);
-       }
-       return true;
-}
-
-static bool check_group(struct group *group,
-                       struct tal_hdr *t, const char *errorstr)
-{
-       struct tal_hdr *i;
+               struct tal_hdr *i;
 
-       i = t;
-       do {
-               if (!check_node(group, i, errorstr))
+               if (!list_check(&children->children, errorstr))
                        return false;
-               group = NULL;
-               i = i->next;
-       } while (i != t);
+               list_for_each(&children->children, i, list) {
+                       if (!check_node(children, i, errorstr))
+                               return false;
+               }
+       }
        return true;
 }
 
@@ -1011,7 +978,7 @@ bool tal_check(const tal_t *ctx, const char *errorstr)
 {
        struct tal_hdr *t = to_tal_hdr_or_null(ctx);
 
-       return check_node(NULL, t, errorstr);
+       return check_node(ignore_destroying_bit(t->parent_child), t, errorstr);
 }
 #else /* NDEBUG */
 bool tal_check(const tal_t *ctx, const char *errorstr)