libudev: rework list handling

1 files changed, 193 insertions, 0 deletions

diff --git a/udev/lib/libudev-list.c b/udev/lib/libudev-list.c
new file mode 100644
index 0000000000..553edf69f8
--- /dev/null
+++ b/udev/lib/libudev-list.c
@@ -0,0 +1,193 @@
+/*
+ * libudev - interface to udev device information
+ *
+ * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#include "libudev.h"
+#include "libudev-private.h"
+
+struct udev_list {
+	struct udev *udev;
+	struct list_node node;
+	struct list_node *list;
+	char *name;
+	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;
+}
+
+void list_init(struct list_node *list)
+{
+	list->next = list;
+	list->prev = list;
+}
+
+static int list_empty(struct list_node *list)
+{
+	return list->next == list;
+}
+
+#if 0
+static void list_add(struct list_node *new, struct list_node *list)
+{
+	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)
+{
+	struct list_node *prev = entry->prev;
+	struct list_node *next = entry->next;
+
+	next->prev = prev;
+	prev->next = next;
+}
+
+#define list_for_each_entry(pos, list) \
+	for (pos = node_to_entry((list)->next); \
+	     &pos->node != (list); \
+	     pos = node_to_entry(pos->node.next))
+
+#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))
+
+struct udev_list *list_insert_entry(struct udev *udev, struct list_node *list,
+				    const char *name, const char *value, int sort)
+{
+	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;
+		}
+	}
+
+	if (sort) {
+		list_for_each_entry(list_loop, list) {
+			if (strcmp(list_loop->name, name) > 0)
+				break;
+		}
+	}
+
+	list_new = malloc(sizeof(struct udev_list));
+	if (list_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);
+		return NULL;
+	}
+	if (value != NULL) {
+		list_new->value = strdup(value);
+		if (list_new->value == NULL) {
+			free(list_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;
+}
+
+void list_move_entry_to_end(struct udev_list *list_entry, struct list_node *list)
+{
+	list_del(&list_entry->node);
+	list_add_to_end(&list_entry->node, 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 *list_get_entry(struct list_node *list)
+{
+	if (list_empty(list))
+		return NULL;
+	return node_to_entry(list->next);
+}
+
+struct udev_list *udev_list_entry_get_next(struct udev_list *list_entry)
+{
+	struct list_node *next;
+
+	next = list_entry->node.next;
+	/* empty list or no more emtries */
+	if (next == list_entry->list)
+		return NULL;
+	return node_to_entry(next);
+}
+
+const char *udev_list_entry_get_name(struct udev_list *list_entry)
+{
+	if (list_entry == NULL)
+		return NULL;
+	return list_entry->name;
+}
+
+const char *udev_list_entry_get_value(struct udev_list *list_entry)
+{
+	if (list_entry == NULL)
+		return NULL;
+	return list_entry->value;
+}