libudev: more list rework

1 files changed, 98 insertions, 84 deletions

diff --git a/udev/lib/libudev-list.c b/udev/lib/libudev-list.c
index 553edf69f8..895c665e40 100644
--- a/udev/lib/libudev-list.c
+++ b/udev/lib/libudev-list.c
@@ -27,7 +27,7 @@
 #include "libudev.h"
 #include "libudev-private.h"
 
-struct udev_list {
+struct udev_list_entry {
 	struct udev *udev;
 	struct list_node node;
 	struct list_node *list;
@@ -35,157 +35,171 @@ struct udev_list {
 	char *value;
 };
 
-static struct udev_list *node_to_entry(struct list_node *node)
-{
-	char *list;
-
-	list = (char *)node;
-	list -= offsetof(struct udev_list, node);
-	return (struct udev_list *)list;
-}
-
+/* list head point to itself if empty */
 void list_init(struct list_node *list)
 {
 	list->next = list;
 	list->prev = list;
 }
 
-static int list_empty(struct list_node *list)
+static int list_is_empty(struct list_node *list)
 {
 	return list->next == list;
 }
 
-#if 0
-static void list_add(struct list_node *new, struct list_node *list)
+static void list_node_insert_between(struct list_node *new,
+				     struct list_node *prev,
+				     struct list_node *next)
 {
-	struct list_node *next = list->next;
-
 	next->prev = new;
 	new->next = next;
-	new->prev = list;
-	list->next = new;
-}
-#endif
-
-static void list_add_to_end(struct list_node *new, struct list_node *list)
-{
-	struct list_node *prev = list->prev;
-
-	list->prev = new;
-	new->next = list;
 	new->prev = prev;
 	prev->next = new;
 }
 
-static void list_del(struct list_node *entry)
+static void list_node_remove(struct list_node *entry)
 {
 	struct list_node *prev = entry->prev;
 	struct list_node *next = entry->next;
 
 	next->prev = prev;
 	prev->next = next;
+
+	entry->prev = NULL;
+	entry->next = NULL;
 }
 
-#define list_for_each_entry(pos, list) \
-	for (pos = node_to_entry((list)->next); \
-	     &pos->node != (list); \
-	     pos = node_to_entry(pos->node.next))
+/* return list entry which embeds this node */
+static struct udev_list_entry *list_node_to_entry(struct list_node *node)
+{
+	char *list;
 
-#define list_for_each_entry_safe(pos, tmp, list) \
-	for (pos = node_to_entry((list)->next), \
-	     tmp = node_to_entry(pos->node.next); \
-	     &pos->node != (list); \
-	     pos = tmp, tmp = node_to_entry(tmp->node.next))
+	list = (char *)node;
+	list -= offsetof(struct udev_list_entry, node);
+	return (struct udev_list_entry *)list;
+}
+
+/* insert entry into a list as the last element  */
+static void list_entry_append(struct udev_list_entry *new, struct list_node *list)
+{
+	/* inserting before the list head make the node the last node in the list */
+	list_node_insert_between(&new->node, list->prev, list);
+	new->list = list;
+}
+
+/* insert entry into a list, before a given existing entry */
+static void list_entry_insert_before(struct udev_list_entry *new, struct udev_list_entry *entry)
+{
+	list_node_insert_between(&new->node, entry->node.prev, &entry->node);
+	new->list = entry->list;
+}
 
-struct udev_list *list_insert_entry(struct udev *udev, struct list_node *list,
-				    const char *name, const char *value, int sort)
+void list_entry_remove(struct udev_list_entry *entry)
 {
-	struct udev_list *list_loop;
-	struct udev_list *list_new;
-
-	/* avoid duplicate entries */
-	list_for_each_entry(list_loop, list) {
-		if (strcmp(list_loop->name, name) == 0) {
-			dbg(udev, "'%s' is already in the list\n", name);
-			return list_loop;
+	list_node_remove(&entry->node);
+	entry->list = NULL;
+}
+
+struct udev_list_entry *list_entry_add(struct udev *udev, struct list_node *list,
+				       const char *name, const char *value,
+				       int unique, int sort)
+{
+	struct udev_list_entry *entry_loop = NULL;
+	struct udev_list_entry *entry_new;
+
+	if (unique)
+		udev_list_entry_foreach(entry_loop, list_get_entry(list)) {
+			if (strcmp(entry_loop->name, name) == 0) {
+				info(udev, "'%s' is already in the list\n", name);
+				if (value != NULL) {
+					free(entry_loop->value);
+					entry_loop->value = strdup(value);
+					if (entry_loop->value == NULL)
+						return NULL;
+					info(udev, "'%s' value replaced with '%s'\n", name, value);
+				}
+				return entry_loop;
+			}
 		}
-	}
 
-	if (sort) {
-		list_for_each_entry(list_loop, list) {
-			if (strcmp(list_loop->name, name) > 0)
+	if (sort)
+		udev_list_entry_foreach(entry_loop, list_get_entry(list)) {
+			if (strcmp(entry_loop->name, name) > 0)
 				break;
 		}
-	}
 
-	list_new = malloc(sizeof(struct udev_list));
-	if (list_new == NULL)
+	entry_new = malloc(sizeof(struct udev_list_entry));
+	if (entry_new == NULL)
 		return NULL;
-	memset(list_new, 0x00, sizeof(struct udev_list));
-	list_new->udev = udev;
-	list_new->list = list;
-	list_new->name = strdup(name);
-	if (list_new->name == NULL) {
-		free(list_new);
+	memset(entry_new, 0x00, sizeof(struct udev_list_entry));
+	entry_new->udev = udev;
+	entry_new->name = strdup(name);
+	if (entry_new->name == NULL) {
+		free(entry_new);
 		return NULL;
 	}
 	if (value != NULL) {
-		list_new->value = strdup(value);
-		if (list_new->value == NULL) {
-			free(list_new);
+		entry_new->value = strdup(value);
+		if (entry_new->value == NULL) {
+			free(entry_new->name);
+			free(entry_new);
 			return NULL;
 		}
 	}
-	dbg(udev, "adding '%s=%s'\n", list_new->name, list_new->value);
-	list_add_to_end(&list_new->node, &list_loop->node);
-	return list_new;
+	if (entry_loop != NULL)
+		list_entry_insert_before(entry_new, entry_loop);
+	else
+		list_entry_append(entry_new, list);
+	return entry_new;
 }
 
-void list_move_entry_to_end(struct udev_list *list_entry, struct list_node *list)
+void list_entry_move_to_end(struct udev_list_entry *list_entry)
 {
-	list_del(&list_entry->node);
-	list_add_to_end(&list_entry->node, list);
+	list_node_remove(&list_entry->node);
+	list_node_insert_between(&list_entry->node, list_entry->list->prev, list_entry->list);
 }
 
 void list_cleanup(struct udev *udev, struct list_node *list)
 {
-	struct udev_list *list_loop;
-	struct udev_list *list_tmp;
-
-	list_for_each_entry_safe(list_loop, list_tmp, list) {
-		list_del(&list_loop->node);
-		free(list_loop->name);
-		free(list_loop->value);
-		free(list_loop);
+	struct udev_list_entry *entry_loop;
+	struct udev_list_entry *entry_tmp;
+
+	list_entry_foreach_safe(entry_loop, entry_tmp, list_get_entry(list)) {
+		list_entry_remove(entry_loop);
+		free(entry_loop->name);
+		free(entry_loop->value);
+		free(entry_loop);
 	}
 }
 
-struct udev_list *list_get_entry(struct list_node *list)
+struct udev_list_entry *list_get_entry(struct list_node *list)
 {
-	if (list_empty(list))
+	if (list_is_empty(list))
 		return NULL;
-	return node_to_entry(list->next);
+	return list_node_to_entry(list->next);
 }
 
-struct udev_list *udev_list_entry_get_next(struct udev_list *list_entry)
+struct udev_list_entry *udev_list_entry_get_next(struct udev_list_entry *list_entry)
 {
 	struct list_node *next;
 
+	if (list_entry == NULL)
+		return NULL;
 	next = list_entry->node.next;
-	/* empty list or no more emtries */
+	/* empty list or no more entries */
 	if (next == list_entry->list)
 		return NULL;
-	return node_to_entry(next);
+	return list_node_to_entry(next);
 }
 
-const char *udev_list_entry_get_name(struct udev_list *list_entry)
+const char *udev_list_entry_get_name(struct udev_list_entry *list_entry)
 {
 	if (list_entry == NULL)
 		return NULL;
 	return list_entry->name;
 }
 
-const char *udev_list_entry_get_value(struct udev_list *list_entry)
+const char *udev_list_entry_get_value(struct udev_list_entry *list_entry)
 {
 	if (list_entry == NULL)
 		return NULL;