X-Git-Url: http://git.openwrt.org/?p=project%2Fuci.git;a=blobdiff_plain;f=list.c;h=24ed2ee6ddf1fa84adf84acc11ab455086f83df9;hp=0ddf4093644edff97b979d778734a2bfd705c972;hb=HEAD;hpb=aa5b36c343894dc01ab857f0c7ab3aa1a792fc05

diff --git a/list.c b/list.c
index 0ddf409..304c9e1 100644
--- a/list.c
+++ b/list.c
@@ -9,56 +9,32 @@
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
+ * GNU Lesser General Public License for more details.
  */
 
-/* initialize a list head/item */
-static inline void uci_list_init(struct uci_list *ptr)
+static bool uci_list_set_pos(struct uci_list *head, struct uci_list *ptr, int pos)
 {
-	ptr->prev = ptr;
-	ptr->next = ptr;
-}
-
-/* inserts a new list entry after a given entry */
-static inline void uci_list_insert(struct uci_list *list, struct uci_list *ptr)
-{
-	list->next->prev = ptr;
-	ptr->prev = list;
-	ptr->next = list->next;
-	list->next = ptr;
-}
-
-/* inserts a new list entry at the tail of the list */
-static inline void uci_list_add(struct uci_list *head, struct uci_list *ptr)
-{
-	/* NB: head->prev points at the tail */
-	uci_list_insert(head->prev, ptr);
-}
-
-static inline void uci_list_del(struct uci_list *ptr)
-{
-	struct uci_list *next, *prev;
-
-	next = ptr->next;
-	prev = ptr->prev;
+	struct uci_list *old_head = ptr->prev;
+	struct uci_list *new_head = head;
+	struct uci_element *p = NULL;
 
-	prev->next = next;
-	next->prev = prev;
+	uci_list_del(ptr);
+	uci_foreach_element(head, p) {
+		if (pos-- <= 0)
+			break;
+		new_head = &p->list;
+	}
 
-	uci_list_init(ptr);
-}
+	uci_list_add(new_head->next, ptr);
 
-static inline void uci_list_fixup(struct uci_list *ptr)
-{
-	ptr->prev->next = ptr;
-	ptr->next->prev = ptr;
+	return (old_head != new_head);
 }
 
-/* 
+/*
  * uci_alloc_generic allocates a new uci_element with payload
  * payload is appended to the struct to save memory and reduce fragmentation
  */
-static struct uci_element *
+__private struct uci_element *
 uci_alloc_generic(struct uci_context *ctx, int type, const char *name, int size)
 {
 	struct uci_element *e;
@@ -84,18 +60,17 @@ done:
 	return e;
 }
 
-static void
+__private void
 uci_free_element(struct uci_element *e)
 {
-	if (e->name)
-		free(e->name);
+	free(e->name);
 	if (!uci_list_empty(&e->list))
 		uci_list_del(&e->list);
 	free(e);
 }
 
 static struct uci_option *
-uci_alloc_option(struct uci_section *s, const char *name, const char *value)
+uci_alloc_option(struct uci_section *s, const char *name, const char *value, struct uci_list *after)
 {
 	struct uci_package *p = s->package;
 	struct uci_context *ctx = p->ctx;
@@ -106,7 +81,7 @@ uci_alloc_option(struct uci_section *s, const char *name, const char *value)
 	o->v.string = uci_dataptr(o);
 	o->section = s;
 	strcpy(o->v.string, value);
-	uci_list_add(&s->options, &o->e.list);
+	uci_list_insert(after ? after : s->options.prev, &o->e.list);
 
 	return o;
 }
@@ -134,7 +109,7 @@ uci_free_option(struct uci_option *o)
 }
 
 static struct uci_option *
-uci_alloc_list(struct uci_section *s, const char *name)
+uci_alloc_list(struct uci_section *s, const char *name, struct uci_list *after)
 {
 	struct uci_package *p = s->package;
 	struct uci_context *ctx = p->ctx;
@@ -144,15 +119,31 @@ uci_alloc_list(struct uci_section *s, const char *name)
 	o->type = UCI_TYPE_LIST;
 	o->section = s;
 	uci_list_init(&o->v.list);
-	uci_list_add(&s->options, &o->e.list);
+	uci_list_insert(after ? after : s->options.prev, &o->e.list);
 
 	return o;
 }
 
+/* Based on an efficient hash function published by D. J. Bernstein */
+static unsigned int djbhash(unsigned int hash, char *str)
+{
+	int len = strlen(str);
+	int i;
+
+	/* initial value */
+	if (hash == ~0U)
+		hash = 5381;
+
+	for(i = 0; i < len; i++) {
+		hash = ((hash << 5) + hash) + str[i];
+	}
+	return (hash & 0x7FFFFFFF);
+}
+
 /* fix up an unnamed section, e.g. after adding options to it */
 static void uci_fixup_section(struct uci_context *ctx, struct uci_section *s)
 {
-	unsigned int hash = ~0;
+	unsigned int hash = ~0U;
 	struct uci_element *e;
 	char buf[16];
 
@@ -181,12 +172,30 @@ static void uci_fixup_section(struct uci_context *ctx, struct uci_section *s)
 			break;
 		}
 	}
-	sprintf(buf, "cfg%02x%04x", ++s->package->n_section, hash % (1 << 16));
+	sprintf(buf, "cfg%02x%04x", s->package->n_section, hash % (1 << 16));
 	s->e.name = uci_strdup(ctx, buf);
 }
 
+/* transfer options between two sections */
+static void uci_section_transfer_options(struct uci_section *dst, struct uci_section *src)
+{
+	struct uci_element *e;
+
+	/* transfer the option list by inserting the new list HEAD and removing the old */
+	uci_list_insert(&src->options, &dst->options);
+	uci_list_del(&src->options);
+
+	/* update pointer to section in options */
+	uci_foreach_element(&dst->options, e) {
+		struct uci_option *o;
+
+		o = uci_to_option(e);
+		o->section = dst;
+	}
+}
+
 static struct uci_section *
-uci_alloc_section(struct uci_package *p, const char *type, const char *name)
+uci_alloc_section(struct uci_package *p, const char *type, const char *name, struct uci_list *after)
 {
 	struct uci_context *ctx = p->ctx;
 	struct uci_section *s;
@@ -203,7 +212,7 @@ uci_alloc_section(struct uci_package *p, const char *type, const char *name)
 		s->anonymous = true;
 	p->n_section++;
 
-	uci_list_add(&p->sections, &s->e.list);
+	uci_list_insert(after ? after : p->sections.prev, &s->e.list);
 
 	return s;
 }
@@ -222,7 +231,7 @@ uci_free_section(struct uci_section *s)
 	uci_free_element(&s->e);
 }
 
-__plugin struct uci_package *
+__private struct uci_package *
 uci_alloc_package(struct uci_context *ctx, const char *name)
 {
 	struct uci_package *p;
@@ -230,12 +239,12 @@ uci_alloc_package(struct uci_context *ctx, const char *name)
 	p = uci_alloc_element(ctx, package, name, 0);
 	p->ctx = ctx;
 	uci_list_init(&p->sections);
-	uci_list_init(&p->history);
-	uci_list_init(&p->saved_history);
+	uci_list_init(&p->delta);
+	uci_list_init(&p->saved_delta);
 	return p;
 }
 
-static void
+__private void
 uci_free_package(struct uci_package **package)
 {
 	struct uci_element *e, *tmp;
@@ -244,16 +253,15 @@ uci_free_package(struct uci_package **package)
 	if(!p)
 		return;
 
-	if (p->path)
-		free(p->path);
+	free(p->path);
 	uci_foreach_element_safe(&p->sections, tmp, e) {
 		uci_free_section(uci_to_section(e));
 	}
-	uci_foreach_element_safe(&p->history, tmp, e) {
-		uci_free_history(uci_to_history(e));
+	uci_foreach_element_safe(&p->delta, tmp, e) {
+		uci_free_delta(uci_to_delta(e));
 	}
-	uci_foreach_element_safe(&p->saved_history, tmp, e) {
-		uci_free_history(uci_to_history(e));
+	uci_foreach_element_safe(&p->saved_delta, tmp, e) {
+		uci_free_delta(uci_to_delta(e));
 	}
 	uci_free_element(&p->e);
 	*package = NULL;
@@ -275,7 +283,7 @@ uci_free_any(struct uci_element **e)
 	*e = NULL;
 }
 
-static inline struct uci_element *
+__private struct uci_element *
 uci_lookup_list(struct uci_list *list, const char *name)
 {
 	struct uci_element *e;
@@ -322,10 +330,10 @@ uci_lookup_ext_section(struct uci_context *ctx, struct uci_ptr *ptr)
 
 	if (!*name)
 		name = NULL;
-	else if (!uci_validate_str(name, false))
+	else if (!uci_validate_type(name))
 		goto error;
 
-	/* if the given index is negative, it specifies the section number from 
+	/* if the given index is negative, it specifies the section number from
 	 * the end of the list */
 	if (idx < 0) {
 		c = 0;
@@ -353,7 +361,7 @@ uci_lookup_ext_section(struct uci_context *ctx, struct uci_ptr *ptr)
 	goto done;
 
 error:
-	e = NULL;
+	free(section);
 	memset(ptr, 0, sizeof(struct uci_ptr));
 	UCI_THROW(ctx, UCI_ERR_INVAL);
 done:
@@ -363,6 +371,18 @@ done:
 	return e;
 }
 
+int
+uci_lookup_next(struct uci_context *ctx, struct uci_element **e, struct uci_list *list, const char *name)
+{
+	UCI_HANDLE_ERR(ctx);
+
+	*e = uci_lookup_list(list, name);
+	if (!*e)
+		UCI_THROW(ctx, UCI_ERR_NOTFOUND);
+
+	return 0;
+}
+
 int
 uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended)
 {
@@ -377,7 +397,11 @@ uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool ext
 	ptr->flags |= UCI_LOOKUP_DONE;
 
 	/* look up the package first */
-	e = uci_lookup_list(&ctx->root, ptr->package);
+	if (ptr->p)
+		e = &ptr->p->e;
+	else
+		e = uci_lookup_list(&ctx->root, ptr->package);
+
 	if (!e) {
 		UCI_INTERNAL(uci_load, ctx, ptr->package, &ptr->p);
 		if (!ptr->p)
@@ -388,15 +412,21 @@ uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool ext
 		ptr->last = e;
 	}
 
-	if (!ptr->section)
+	if (!ptr->section && !ptr->s)
 		goto complete;
 
 	/* if the section name validates as a regular name, pass through
 	 * to the regular uci_lookup function call */
-	if (ptr->flags & UCI_LOOKUP_EXTENDED)
-		e = uci_lookup_ext_section(ctx, ptr);
-	else
+	if (ptr->s) {
+		e = &ptr->s->e;
+	} else if (ptr->flags & UCI_LOOKUP_EXTENDED) {
+		if (extended)
+			e = uci_lookup_ext_section(ctx, ptr);
+		else
+			UCI_THROW(ctx, UCI_ERR_INVAL);
+	} else {
 		e = uci_lookup_list(&ptr->p->sections, ptr->section);
+	}
 
 	if (!e)
 		goto abort;
@@ -416,58 +446,21 @@ uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool ext
 complete:
 	ptr->flags |= UCI_LOOKUP_COMPLETE;
 abort:
-	return 0;
+	return UCI_OK;
 
 notfound:
 	UCI_THROW(ctx, UCI_ERR_NOTFOUND);
-	return 0;
+	/* not a chance here */
+	return UCI_ERR_NOTFOUND;
 }
 
-int
-uci_fill_ptr(struct uci_context *ctx, struct uci_ptr *ptr, struct uci_element *e, bool complete)
-{
-	UCI_HANDLE_ERR(ctx);
-	UCI_ASSERT(ctx, ptr != NULL);
-	UCI_ASSERT(ctx, e != NULL);
-
-	memset(ptr, 0, sizeof(struct uci_ptr));
-	switch(e->type) {
-	case UCI_TYPE_OPTION:
-		ptr->o = uci_to_option(e);
-		goto fill_option;
-	case UCI_TYPE_SECTION:
-		ptr->s = uci_to_section(e);
-		goto fill_section;
-	case UCI_TYPE_PACKAGE:
-		ptr->p = uci_to_package(e);
-		goto fill_package;
-	default:
-		UCI_THROW(ctx, UCI_ERR_INVAL);
-	}
-
-fill_option:
-	ptr->option = ptr->o->e.name;
-	ptr->s = ptr->o->section;
-fill_section:
-	ptr->section = ptr->s->e.name;
-	ptr->p = ptr->s->package;
-fill_package:
-	ptr->package = ptr->p->e.name;
-
-	ptr->flags |= UCI_LOOKUP_DONE;
-	if (complete)
-		ptr->flags |= UCI_LOOKUP_COMPLETE;
-
-	return 0;
-}
-
-static struct uci_element *
-expand_ptr(struct uci_context *ctx, struct uci_ptr *ptr, bool complete)
+__private struct uci_element *
+uci_expand_ptr(struct uci_context *ctx, struct uci_ptr *ptr, bool complete)
 {
 	UCI_ASSERT(ctx, ptr != NULL);
 
 	if (!(ptr->flags & UCI_LOOKUP_DONE))
-		uci_lookup_ptr(ctx, ptr, NULL, 1);
+		UCI_INTERNAL(uci_lookup_ptr, ctx, ptr, NULL, 1);
 	if (complete && !(ptr->flags & UCI_LOOKUP_COMPLETE))
 		UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 	UCI_ASSERT(ctx, ptr->p != NULL);
@@ -490,58 +483,66 @@ expand_ptr(struct uci_context *ctx, struct uci_ptr *ptr, bool complete)
 		return NULL;
 }
 
-static void uci_add_element_list(struct uci_context *ctx, struct uci_ptr *ptr, bool internal)
-{
-	struct uci_element *e;
-	struct uci_package *p;
-
-	p = ptr->p;
-	if (!internal && p->has_history)
-		uci_add_history(ctx, &p->history, UCI_CMD_LIST_ADD, ptr->section, ptr->option, ptr->value);
-
-	e = uci_alloc_generic(ctx, UCI_TYPE_ITEM, ptr->value, sizeof(struct uci_option));
-	uci_list_add(&ptr->o->v.list, &e->list);
-}
-
 int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr)
 {
-	/* NB: UCI_INTERNAL use means without history tracking */
-	bool internal = ctx->internal;
+	/* NB: UCI_INTERNAL use means without delta tracking */
+	bool internal = ctx && ctx->internal;
 	struct uci_element *e;
 	struct uci_package *p;
 	char *n;
 
 	UCI_HANDLE_ERR(ctx);
 
-	e = expand_ptr(ctx, ptr, true);
+	e = uci_expand_ptr(ctx, ptr, true);
 	p = ptr->p;
 
 	UCI_ASSERT(ctx, ptr->s);
 	UCI_ASSERT(ctx, ptr->value);
 
-	if (!internal && p->has_history)
-		uci_add_history(ctx, &p->history, UCI_CMD_RENAME, ptr->section, ptr->option, ptr->value);
+	if (!internal && p->has_delta)
+		uci_add_delta(ctx, &p->delta, UCI_CMD_RENAME, ptr->section, ptr->option, ptr->value);
 
 	n = uci_strdup(ctx, ptr->value);
-	if (e->name)
-		free(e->name);
+	free(e->name);
 	e->name = n;
 
+	if (e->type == UCI_TYPE_SECTION)
+		uci_to_section(e)->anonymous = false;
+
+	return 0;
+}
+
+int uci_reorder_section(struct uci_context *ctx, struct uci_section *s, int pos)
+{
+	struct uci_package *p = s->package;
+	bool internal = ctx && ctx->internal;
+	bool changed = false;
+	char order[32];
+
+	UCI_HANDLE_ERR(ctx);
+
+	changed = uci_list_set_pos(&s->package->sections, &s->e.list, pos);
+	if (!internal && p->has_delta && changed) {
+		sprintf(order, "%d", pos);
+		uci_add_delta(ctx, &p->delta, UCI_CMD_REORDER, s->e.name, NULL, order);
+	}
+
 	return 0;
 }
 
 int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res)
 {
-	bool internal = ctx->internal;
+	bool internal = ctx && ctx->internal;
 	struct uci_section *s;
 
 	UCI_HANDLE_ERR(ctx);
 	UCI_ASSERT(ctx, p != NULL);
-	s = uci_alloc_section(p, type, NULL);
-	uci_fixup_section(ctx, s);
+	s = uci_alloc_section(p, type, NULL, NULL);
+	if (s && s->anonymous)
+		uci_fixup_section(ctx, s);
 	*res = s;
-	if (!internal && p->has_history)
-		uci_add_history(ctx, &p->history, UCI_CMD_ADD, s->e.name, NULL, type);
+	if (!internal && p->has_delta)
+		uci_add_delta(ctx, &p->delta, UCI_CMD_ADD, s->e.name, NULL, type);
 
 	return 0;
 }
@@ -549,76 +550,145 @@ int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *
 int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr)
 {
 	/* NB: pass on internal flag to uci_del_element */
-	bool internal = ctx->internal;
+	bool internal = ctx && ctx->internal;
 	struct uci_package *p;
-	struct uci_element *e;
+	struct uci_element *e1, *e2, *tmp;
+	int index;
 
 	UCI_HANDLE_ERR(ctx);
 
-	e = expand_ptr(ctx, ptr, true);
+	e1 = uci_expand_ptr(ctx, ptr, true);
 	p = ptr->p;
 
 	UCI_ASSERT(ctx, ptr->s);
 
-	if (!internal && p->has_history)
-		uci_add_history(ctx, &p->history, UCI_CMD_REMOVE, ptr->section, ptr->option, NULL);
+	if (ptr->o && ptr->o->type == UCI_TYPE_LIST && ptr->value && *ptr->value) {
+		if (!sscanf(ptr->value, "%d", &index))
+			return 1;
+
+		uci_foreach_element_safe(&ptr->o->v.list, tmp, e2) {
+			if (index == 0) {
+				if (!internal && p->has_delta)
+					uci_add_delta(ctx, &p->delta, UCI_CMD_REMOVE, ptr->section, ptr->option, ptr->value);
+				uci_free_option(uci_to_option(e2));
+				return 0;
+			}
+			index--;
+		}
+
+		return 0;
+	}
+
+	if (!internal && p->has_delta)
+		uci_add_delta(ctx, &p->delta, UCI_CMD_REMOVE, ptr->section, ptr->option, NULL);
+
+	uci_free_any(&e1);
+
+	if (ptr->option)
+		ptr->o = NULL;
+	else if (ptr->section)
+		ptr->s = NULL;
 
-	uci_free_any(&e);
 	return 0;
 }
 
 int uci_add_list(struct uci_context *ctx, struct uci_ptr *ptr)
 {
-	/* NB: UCI_INTERNAL use means without history tracking */
-	bool internal = ctx->internal;
-	struct uci_option *prev = NULL;
-	const char *value2 = NULL;
+	/* NB: UCI_INTERNAL use means without delta tracking */
+	bool internal = ctx && ctx->internal;
+	struct uci_element *volatile e1 = NULL, *volatile e2 = NULL;
 
 	UCI_HANDLE_ERR(ctx);
 
-	expand_ptr(ctx, ptr, false);
+	uci_expand_ptr(ctx, ptr, false);
 	UCI_ASSERT(ctx, ptr->s);
 	UCI_ASSERT(ctx, ptr->value);
 
-	if (ptr->o) {
-		switch (ptr->o->type) {
-		case UCI_TYPE_STRING:
-			/* we already have a string value, convert that to a list */
-			prev = ptr->o;
-			value2 = ptr->value;
-			ptr->value = ptr->o->v.string;
-			break;
-		case UCI_TYPE_LIST:
-			uci_add_element_list(ctx, ptr, internal);
-			return 0;
-		default:
-			UCI_THROW(ctx, UCI_ERR_INVAL);
-			break;
-		}
+	if (ptr->o && ptr->o->type != UCI_TYPE_LIST && ptr->o->type != UCI_TYPE_STRING) {
+		UCI_THROW(ctx, UCI_ERR_INVAL);
 	}
 
-	ptr->o = uci_alloc_list(ptr->s, ptr->option);
-	if (prev) {
-		uci_add_element_list(ctx, ptr, true);
-		uci_free_option(prev);
-		ptr->value = value2;
+	/* create new item */
+	e1 = uci_alloc_generic(ctx, UCI_TYPE_ITEM, ptr->value, sizeof(struct uci_option));
+
+	if (!ptr->o) {
+		/* create new list */
+		UCI_TRAP_SAVE(ctx, error);
+		ptr->o = uci_alloc_list(ptr->s, ptr->option, NULL);
+		UCI_TRAP_RESTORE(ctx);
+	} else if (ptr->o->type == UCI_TYPE_STRING) {
+		/* create new list and add old string value as item to list */
+		struct uci_option *old = ptr->o;
+		UCI_TRAP_SAVE(ctx, error);
+		e2 = uci_alloc_generic(ctx, UCI_TYPE_ITEM, old->v.string, sizeof(struct uci_option));
+		ptr->o = uci_alloc_list(ptr->s, ptr->option, &old->e.list);
+		UCI_TRAP_RESTORE(ctx);
+		uci_list_add(&ptr->o->v.list, &e2->list);
+
+		/* remove old option */
+		if (ptr->option == old->e.name)
+			ptr->option = ptr->o->e.name;
+		uci_free_option(old);
+	}
+
+	/* add new item to list */
+	uci_list_add(&ptr->o->v.list, &e1->list);
+
+	if (!internal && ptr->p->has_delta)
+		uci_add_delta(ctx, &ptr->p->delta, UCI_CMD_LIST_ADD, ptr->section, ptr->option, ptr->value);
+
+	return 0;
+error:
+	if (e1 != NULL)
+		uci_free_element(e1);
+	if (e2 != NULL)
+		uci_free_element(e2);
+	UCI_THROW(ctx, ctx->err);
+}
+
+int uci_del_list(struct uci_context *ctx, struct uci_ptr *ptr)
+{
+	/* NB: pass on internal flag to uci_del_element */
+	bool internal = ctx && ctx->internal;
+	struct uci_element *e, *tmp;
+	struct uci_package *p;
+
+	UCI_HANDLE_ERR(ctx);
+
+	uci_expand_ptr(ctx, ptr, false);
+	UCI_ASSERT(ctx, ptr->s);
+	UCI_ASSERT(ctx, ptr->value);
+
+	if (!(ptr->o && ptr->option))
+		return 0;
+
+	if ((ptr->o->type != UCI_TYPE_LIST))
+		return 0;
+
+	p = ptr->p;
+	if (!internal && p->has_delta)
+		uci_add_delta(ctx, &p->delta, UCI_CMD_LIST_DEL, ptr->section, ptr->option, ptr->value);
+
+	uci_foreach_element_safe(&ptr->o->v.list, tmp, e) {
+		if (!strcmp(ptr->value, uci_to_option(e)->e.name)) {
+			uci_free_option(uci_to_option(e));
+		}
 	}
-	uci_add_element_list(ctx, ptr, internal);
 
 	return 0;
 }
 
 int uci_set(struct uci_context *ctx, struct uci_ptr *ptr)
 {
-	/* NB: UCI_INTERNAL use means without history tracking */
-	bool internal = ctx->internal;
+	/* NB: UCI_INTERNAL use means without delta tracking */
+	bool internal = ctx && ctx->internal;
 
 	UCI_HANDLE_ERR(ctx);
-	expand_ptr(ctx, ptr, false);
+	uci_expand_ptr(ctx, ptr, false);
 	UCI_ASSERT(ctx, ptr->value);
 	UCI_ASSERT(ctx, ptr->s || (!ptr->option && ptr->section));
-	if (!ptr->option) {
-		UCI_ASSERT(ctx, uci_validate_str(ptr->value, false));
+	if (!ptr->option && ptr->value[0]) {
+		UCI_ASSERT(ctx, uci_validate_type(ptr->value));
 	}
 
 	if (!ptr->o && ptr->s && ptr->option) {
@@ -627,37 +697,51 @@ int uci_set(struct uci_context *ctx, struct uci_ptr *ptr)
 		if (e)
 			ptr->o = uci_to_option(e);
 	}
-	if (!ptr->o && ptr->option) { /* new option */
-		ptr->o = uci_alloc_option(ptr->s, ptr->option, ptr->value);
-		ptr->last = &ptr->o->e;
+	if (!ptr->value[0]) {
+		/* if setting a nonexistant option/section to a nonexistant value,
+		 * exit without errors */
+		if (!(ptr->flags & UCI_LOOKUP_COMPLETE))
+			return 0;
+
+		return uci_delete(ctx, ptr);
+	} else if (!ptr->o && ptr->option) { /* new option */
+		ptr->o = uci_alloc_option(ptr->s, ptr->option, ptr->value, NULL);
 	} else if (!ptr->s && ptr->section) { /* new section */
-		ptr->s = uci_alloc_section(ptr->p, ptr->value, ptr->section);
-		ptr->last = &ptr->s->e;
+		ptr->s = uci_alloc_section(ptr->p, ptr->value, ptr->section, NULL);
 	} else if (ptr->o && ptr->option) { /* update option */
-		if ((ptr->o->type == UCI_TYPE_STRING) &&
-			!strcmp(ptr->o->v.string, ptr->value))
+		if (ptr->o->type == UCI_TYPE_STRING && !strcmp(ptr->o->v.string, ptr->value))
 			return 0;
-		uci_free_option(ptr->o);
-		ptr->o = uci_alloc_option(ptr->s, ptr->option, ptr->value);
-		ptr->last = &ptr->o->e;
+
+		if (ptr->o->type == UCI_TYPE_STRING && strlen(ptr->o->v.string) == strlen(ptr->value)) {
+			strcpy(ptr->o->v.string, ptr->value);
+		} else {
+			struct uci_option *old = ptr->o;
+			ptr->o = uci_alloc_option(ptr->s, ptr->option, ptr->value, &old->e.list);
+			if (ptr->option == old->e.name)
+				ptr->option = ptr->o->e.name;
+			uci_free_option(old);
+		}
 	} else if (ptr->s && ptr->section) { /* update section */
-		char *s = uci_strdup(ctx, ptr->value);
+		if (!strcmp(ptr->s->type, ptr->value))
+			return 0;
 
-		if (ptr->s->type == uci_dataptr(ptr->s)) {
-			ptr->last = NULL;
-			ptr->last = uci_realloc(ctx, ptr->s, sizeof(struct uci_section));
-			ptr->s = uci_to_section(ptr->last);
-			uci_list_fixup(&ptr->s->e.list);
+		if (strlen(ptr->s->type) == strlen(ptr->value)) {
+			strcpy(ptr->s->type, ptr->value);
 		} else {
-			free(ptr->s->type);
+			struct uci_section *old = ptr->s;
+			ptr->s = uci_alloc_section(ptr->p, ptr->value, old->e.name, &old->e.list);
+			uci_section_transfer_options(ptr->s, old);
+			if (ptr->section == old->e.name)
+				ptr->section = ptr->s->e.name;
+			uci_free_section(old);
+			ptr->s->package->n_section--;
 		}
-		ptr->s->type = s;
 	} else {
 		UCI_THROW(ctx, UCI_ERR_INVAL);
 	}
 
-	if (!internal && ptr->p->has_history)
-		uci_add_history(ctx, &ptr->p->history, UCI_CMD_CHANGE, ptr->section, ptr->option, ptr->value);
+	if (!internal && ptr->p->has_delta)
+		uci_add_delta(ctx, &ptr->p->delta, UCI_CMD_CHANGE, ptr->section, ptr->option, ptr->value);
 
 	return 0;
 }