]> git.ozlabs.org Git - ccan/blobdiff - ccan/tal/tal.c
tal: allow notifiers on NULL.
[ccan] / ccan / tal / tal.c
index 842059d031b76977d665b31f1aedd3259a86ff0f..f6e2ee797c3e251dae5033bd928e7a61995b2fe6 100644 (file)
@@ -2,31 +2,36 @@
 #include <ccan/tal/tal.h>
 #include <ccan/compiler/compiler.h>
 #include <ccan/list/list.h>
-#include <ccan/take/take.h>
 #include <ccan/alignof/alignof.h>
 #include <assert.h>
 #include <stdio.h>
 #include <stddef.h>
 #include <string.h>
 #include <limits.h>
+#include <stdint.h>
 #include <errno.h>
 
 //#define TAL_DEBUG 1
 
 #define NOTIFY_IS_DESTRUCTOR 512
+#define NOTIFY_EXTRA_ARG 1024
+
+/* This makes our parent_child ptr stand out for to_tal_hdr checks */
+#define TAL_PTR_OBFUSTICATOR ((intptr_t)0x1984200820142016ULL)
 
 /* 32-bit type field, first byte 0 in either endianness. */
 enum prop_type {
        CHILDREN = 0x00c1d500,
        NAME = 0x00111100,
        NOTIFIER = 0x00071f00,
-       LENGTH = 0x00515300
 };
 
 struct tal_hdr {
        struct list_node list;
        struct prop_hdr *prop;
-       struct children *parent_child;
+       /* XOR with TAL_PTR_OBFUSTICATOR */
+       intptr_t parent_child;
+       size_t bytelen;
 };
 
 struct prop_hdr {
@@ -45,25 +50,29 @@ struct name {
        char name[];
 };
 
-struct length {
-       struct prop_hdr hdr; /* LENGTH */
-       size_t len;
-};
-
 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 */
+               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;
 } null_parent = { { { &null_parent.hdr.list, &null_parent.hdr.list },
-                   &null_parent.c.hdr, NULL },
+                   &null_parent.c.hdr, TAL_PTR_OBFUSTICATOR, 0 },
                  { { CHILDREN, NULL },
                    &null_parent.hdr,
                    { { &null_parent.c.children.n,
@@ -84,19 +93,19 @@ static inline void COLD call_error(const char *msg)
        errorfn(msg);
 }
 
-static bool get_destroying_bit(struct children *parent_child)
+static bool get_destroying_bit(intptr_t parent_child)
 {
-       return (size_t)parent_child & 1;
+       return parent_child & 1;
 }
 
-static void set_destroying_bit(struct children **parent_child)
+static void set_destroying_bit(intptr_t *parent_child)
 {
-       *parent_child = (void *)((size_t)*parent_child | 1);
+       *parent_child |= 1;
 }
 
-static struct children *ignore_destroying_bit(struct children *parent_child)
+static struct children *ignore_destroying_bit(intptr_t parent_child)
 {
-       return (void *)((size_t)parent_child & ~(size_t)1);
+       return (void *)((parent_child ^ TAL_PTR_OBFUSTICATOR) & ~(intptr_t)1);
 }
 
 /* This means valgrind can see leaks. */
@@ -182,14 +191,14 @@ static void *from_tal_hdr(const struct tal_hdr *hdr)
        return (void *)(hdr + 1);
 }
 
-#ifdef TAL_DEBUG
-static void *from_tal_hdr_or_null(struct tal_hdr *hdr)
+static void *from_tal_hdr_or_null(const struct tal_hdr *hdr)
 {
        if (hdr == &null_parent.hdr)
                return NULL;
        return from_tal_hdr(hdr);
 }
 
+#ifdef TAL_DEBUG
 static struct tal_hdr *debug_tal(struct tal_hdr *tal)
 {
        tal_check(from_tal_hdr_or_null(tal), "TAL_DEBUG ");
@@ -203,7 +212,8 @@ static struct tal_hdr *debug_tal(struct tal_hdr *tal)
 #endif
 
 static void notify(const struct tal_hdr *ctx,
-                  enum tal_notify_type type, const void *info)
+                  enum tal_notify_type type, const void *info,
+                  int saved_errno)
 {
         const struct prop_hdr *p;
 
@@ -216,10 +226,15 @@ static void notify(const struct tal_hdr *ctx,
                        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,
+                       errno = saved_errno;
+                       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_or_null(ctx), type,
                                              (void *)info);
                }
        }
@@ -274,13 +289,22 @@ 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;
 }
@@ -288,24 +312,33 @@ 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;
 }
@@ -344,11 +377,11 @@ static bool add_child(struct tal_hdr *parent, struct tal_hdr *child)
                        return false;
        }
        list_add(&children->children, &child->list);
-       child->parent_child = children;
+       child->parent_child = (intptr_t)children ^ TAL_PTR_OBFUSTICATOR;
        return true;
 }
 
-static void del_tree(struct tal_hdr *t, const tal_t *orig)
+static void del_tree(struct tal_hdr *t, const tal_t *orig, int saved_errno)
 {
        struct prop_hdr **prop, *p, *next;
 
@@ -359,7 +392,7 @@ static void del_tree(struct tal_hdr *t, const tal_t *orig)
         set_destroying_bit(&t->parent_child);
 
        /* Call free notifiers. */
-       notify(t, TAL_NOTIFY_FREE, (tal_t *)orig);
+       notify(t, TAL_NOTIFY_FREE, (tal_t *)orig, saved_errno);
 
        /* Now free children and groups. */
        prop = find_property_ptr(t, CHILDREN);
@@ -369,70 +402,43 @@ static void del_tree(struct tal_hdr *t, const tal_t *orig)
 
                while ((i = list_top(&c->children, struct tal_hdr, list))) {
                        list_del(&i->list);
-                       del_tree(i, orig);
+                       del_tree(i, orig, saved_errno);
                }
        }
 
         /* Finally free our properties. */
         for (p = t->prop; p && !is_literal(p); p = next) {
                 next = p->next;
-               /* LENGTH is appended, so don't free separately! */
-               if (p->type != LENGTH)
-                       freefn(p);
+               freefn(p);
         }
         freefn(t);
 }
 
-static size_t extra_for_length(size_t size)
+void *tal_alloc_(const tal_t *ctx, size_t size, bool clear, const char *label)
 {
-       size_t extra;
-       const size_t align = ALIGNOF(struct length);
-
-       /* Round up size, and add tailer. */
-       extra = ((size + align-1) & ~(align-1)) - size;
-       extra += sizeof(struct length);
-       return extra;
-}
-
-void *tal_alloc_(const tal_t *ctx, size_t size,
-                bool clear, bool add_length, const char *label)
-{
-       size_t req_size = size;
         struct tal_hdr *child, *parent = debug_tal(to_tal_hdr_or_null(ctx));
 
-#ifdef CCAN_TAL_DEBUG
-       /* Always record length if debugging. */
-       add_length = true;
-#endif
-       if (add_length)
-               size += extra_for_length(size);
-
         child = allocate(sizeof(struct tal_hdr) + size);
        if (!child)
                return NULL;
        if (clear)
-               memset(from_tal_hdr(child), 0, req_size);
+               memset(from_tal_hdr(child), 0, size);
         child->prop = (void *)label;
+       child->bytelen = size;
 
-       if (add_length) {
-               struct length *lprop;
-               lprop = (struct length *)((char *)(child+1) + size) - 1;
-               init_property(&lprop->hdr, child, LENGTH);
-               lprop->len = req_size;
-       }
         if (!add_child(parent, child)) {
                freefn(child);
                return NULL;
        }
        debug_tal(parent);
        if (notifiers)
-               notify(parent, TAL_NOTIFY_ADD_CHILD, from_tal_hdr(child));
+               notify(parent, TAL_NOTIFY_ADD_CHILD, from_tal_hdr(child), 0);
        return from_tal_hdr(debug_tal(child));
 }
 
 static bool adjust_size(size_t *size, size_t count)
 {
-       const size_t extra = sizeof(struct tal_hdr) + sizeof(struct length)*2;
+       const size_t extra = sizeof(struct tal_hdr);
 
        /* Multiplication wrap */
         if (count && unlikely(*size * count / *size != count))
@@ -440,7 +446,7 @@ static bool adjust_size(size_t *size, size_t count)
 
         *size *= count;
 
-        /* Make sure we don't wrap adding header/tailer. */
+        /* Make sure we don't wrap adding header. */
         if (*size + extra < extra)
                goto overflow;
        return true;
@@ -450,12 +456,12 @@ overflow:
 }
 
 void *tal_alloc_arr_(const tal_t *ctx, size_t size, size_t count, bool clear,
-                    bool add_length, const char *label)
+                    const char *label)
 {
        if (!adjust_size(&size, count))
                return NULL;
 
-       return tal_alloc_(ctx, size, clear, add_length, label);
+       return tal_alloc_(ctx, size, clear, label);
 }
 
 void *tal_free(const tal_t *ctx)
@@ -464,11 +470,13 @@ void *tal_free(const tal_t *ctx)
                struct tal_hdr *t;
                int saved_errno = errno;
                t = debug_tal(to_tal_hdr(ctx));
+               if (unlikely(get_destroying_bit(t->parent_child)))
+                       return NULL;
                if (notifiers)
                        notify(ignore_destroying_bit(t->parent_child)->parent,
-                              TAL_NOTIFY_DEL_CHILD, ctx);
+                              TAL_NOTIFY_DEL_CHILD, ctx, saved_errno);
                list_del(&t->list);
-               del_tree(t, ctx);
+               del_tree(t, ctx, saved_errno);
                errno = saved_errno;
        }
        return NULL;
@@ -487,7 +495,7 @@ void *tal_steal_(const tal_t *new_parent, const tal_t *ctx)
                old_parent = ignore_destroying_bit(t->parent_child)->parent;
 
                 if (unlikely(!add_child(newpar, t))) {
-                       /* We can always add to old parent, becuase it has a
+                       /* We can always add to old parent, because it has a
                         * children property already. */
                        if (!add_child(old_parent, t))
                                abort();
@@ -495,7 +503,7 @@ void *tal_steal_(const tal_t *new_parent, const tal_t *ctx)
                }
                debug_tal(newpar);
                if (notifiers)
-                       notify(t, TAL_NOTIFY_STEAL, new_parent);
+                       notify(t, TAL_NOTIFY_STEAL, new_parent, 0);
         }
         return (void *)ctx;
 }
@@ -504,13 +512,23 @@ 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 *))
 {
-       tal_t *t = debug_tal(to_tal_hdr(ctx));
+       struct tal_hdr *t = debug_tal(to_tal_hdr_or_null(ctx));
        struct notifier *n;
 
        assert(types);
@@ -521,12 +539,12 @@ 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;
 
        if (notifiers)
-               notify(t, TAL_NOTIFY_ADD_NOTIFIER, callback);
+               notify(t, TAL_NOTIFY_ADD_NOTIFIER, callback, 0);
 
        n->types = types;
        if (types != TAL_NOTIFY_FREE)
@@ -535,14 +553,15 @@ 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));
+       struct tal_hdr *t = debug_tal(to_tal_hdr_or_null(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);
+               notify(t, TAL_NOTIFY_DEL_NOTIFIER, callback, 0);
                if (types != TAL_NOTIFY_FREE)
                        notifiers--;
                return true;
@@ -552,7 +571,13 @@ 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)
@@ -582,7 +607,7 @@ bool tal_set_name_(tal_t *ctx, const char *name, bool literal)
 
        debug_tal(t);
        if (notifiers)
-               notify(t, TAL_NOTIFY_RENAME, name);
+               notify(t, TAL_NOTIFY_RENAME, name, 0);
        return true;
 }
 
@@ -599,14 +624,12 @@ const char *tal_name(const tal_t *t)
        return n->name;
 }
 
-size_t tal_len(const tal_t *ptr)
+size_t tal_bytelen(const tal_t *ptr)
 {
-       struct length *l;
+       /* NULL -> null_parent which has bytelen 0 */
+       struct tal_hdr *t = debug_tal(to_tal_hdr_or_null(ptr));
 
-       l = find_property(debug_tal(to_tal_hdr(ptr)), LENGTH);
-       if (!l)
-               return 0;
-       return l->len;
+       return t->bytelen;
 }
 
 /* Start one past first child: make stopping natural in circ. list. */
@@ -660,52 +683,27 @@ bool tal_resize_(tal_t **ctxp, size_t size, size_t count, bool clear)
 {
         struct tal_hdr *old_t, *t;
         struct children *child;
-       struct prop_hdr **lenp;
-       struct length len;
-       size_t extra = 0;
 
         old_t = debug_tal(to_tal_hdr(*ctxp));
 
        if (!adjust_size(&size, count))
                return false;
 
-       lenp = find_property_ptr(old_t, LENGTH);
-       if (lenp) {
-               /* Copy here, in case we're shrinking! */
-               len = *(struct length *)*lenp;
-               extra = extra_for_length(size);
-       } else /* If we don't have an old length, we can't clear! */
-               assert(!clear);
-
-        t = resizefn(old_t, sizeof(struct tal_hdr) + size + extra);
+        t = resizefn(old_t, sizeof(struct tal_hdr) + size);
        if (!t) {
                call_error("Reallocation failure");
                return false;
        }
 
-       /* Copy length to end. */
-       if (lenp) {
-               struct length *new_len;
-
-               /* Clear between old end and new end. */
-               if (clear && size > len.len) {
-                       char *old_end = (char *)(t + 1) + len.len;
-                       memset(old_end, 0, size - len.len);
-               }
-
-               new_len = (struct length *)((char *)(t + 1) + size
-                                           + extra - sizeof(len));
-               len.len = size;
-               *new_len = len;
-
-               /* Be careful replacing next ptr; could be old hdr. */
-               if (lenp == &old_t->prop)
-                       t->prop = &new_len->hdr;
-               else
-                       *lenp = &new_len->hdr;
+       /* Clear between old end and new end. */
+       if (clear && size > t->bytelen) {
+               char *old_end = (char *)(t + 1) + t->bytelen;
+               memset(old_end, 0, size - t->bytelen);
        }
 
-       update_bounds(t, sizeof(struct tal_hdr) + size + extra);
+       /* Update length. */
+       t->bytelen = size;
+       update_bounds(t, sizeof(struct tal_hdr) + size);
 
        /* If it didn't move, we're done! */
         if (t != old_t) {
@@ -720,22 +718,20 @@ bool tal_resize_(tal_t **ctxp, size_t size, size_t count, bool clear)
                }
                *ctxp = from_tal_hdr(debug_tal(t));
                if (notifiers)
-                       notify(t, TAL_NOTIFY_MOVE, from_tal_hdr(old_t));
+                       notify(t, TAL_NOTIFY_MOVE, from_tal_hdr(old_t), 0);
        }
        if (notifiers)
-               notify(t, TAL_NOTIFY_RESIZE, (void *)size);
+               notify(t, TAL_NOTIFY_RESIZE, (void *)size, 0);
 
        return true;
 }
 
 bool tal_expand_(tal_t **ctxp, const void *src, size_t size, size_t count)
 {
-       struct length *l;
        size_t old_len;
        bool ret = false;
 
-       l = find_property(debug_tal(to_tal_hdr(*ctxp)), LENGTH);
-       old_len = l->len;
+       old_len = debug_tal(to_tal_hdr(*ctxp))->bytelen;
 
        /* Check for additive overflow */
        if (old_len + count * size < old_len) {
@@ -760,8 +756,7 @@ out:
 }
 
 void *tal_dup_(const tal_t *ctx, const void *p, size_t size,
-              size_t n, size_t extra, bool add_length,
-              const char *label)
+              size_t n, size_t extra, const char *label)
 {
        void *ret;
        size_t nbytes = size;
@@ -790,7 +785,7 @@ void *tal_dup_(const tal_t *ctx, const void *p, size_t size,
                return (void *)p;
        }
 
-       ret = tal_alloc_arr_(ctx, size, n + extra, false, add_length, label);
+       ret = tal_alloc_arr_(ctx, size, n + extra, false, label);
        if (ret)
                memcpy(ret, p, nbytes);
        return ret;
@@ -819,12 +814,11 @@ static void dump_node(unsigned int indent, const struct tal_hdr *t)
 
        for (i = 0; i < indent; i++)
                printf("  ");
-       printf("%p", t);
+       printf("%p len=%zu", t, t->bytelen);
         for (p = t->prop; p; p = p->next) {
                struct children *c;
                struct name *n;
                struct notifier *no;
-               struct length *l;
                 if (is_literal(p)) {
                        printf(" \"%s\"", (const char *)p);
                        break;
@@ -844,10 +838,6 @@ static void dump_node(unsigned int indent, const struct tal_hdr *t)
                        no = (struct notifier *)p;
                        printf(" NOTIFIER(%p):fn=%p", p, no->u.notifyfn);
                        break;
-               case LENGTH:
-                       l = (struct length *)p;
-                       printf(" LENGTH(%p):len=%zu", p, l->len);
-                       break;
                default:
                        printf(" **UNKNOWN(%p):%i**", p, p->type);
                }
@@ -895,7 +885,6 @@ static bool check_node(struct children *parent_child,
        struct prop_hdr *p;
        struct name *name = NULL;
        struct children *children = NULL;
-       struct length *length = NULL;
 
        if (!in_bounds(t))
                return check_err(t, errorstr, "invalid pointer");
@@ -921,12 +910,6 @@ static bool check_node(struct children *parent_child,
                                                 "has two child nodes");
                        children = (struct children *)p;
                        break;
-               case LENGTH:
-                       if (length)
-                               return check_err(t, errorstr,
-                                                "has two lengths");
-                       length = (struct length *)p;
-                       break;
                case NOTIFIER:
                        break;
                case NAME: