New package: list, complete reimplementation of Linux's list macros.

diff --git a/list/_info.c b/list/_info.c
new file mode 100644 (file)
index 0000000..5e22882
--- /dev/null
+++ b/list/_info.c
@@ -0,0 +1,63 @@
+#include <stdio.h>
+#include <string.h>
+#include "config.h"
+
+/**
+ * list - double linked list routines
+ *
+ * The list header contains routines for manipulating double linked lists.
+ * It defined two types: struct list_head used for anchoring lists, and
+ * struct list_node which is usually embedded in the structure which is placed
+ * in the list.
+ *
+ * Example:
+ *     #include <err.h>
+ *     #include "list/list.h"
+ *
+ *     struct parent {
+ *             const char *name;
+ *             struct list_head children;
+ *             unsigned int num_children;
+ *     };
+ *
+ *     struct child {
+ *             const char *name;
+ *             struct list_node list;
+ *     };
+ *
+ *     int main(int argc, char *argv[])
+ *     {
+ *             struct parent p;
+ *             struct child *c;
+ *             unsigned int i;
+ *
+ *             if (argc < 2)
+ *                     errx(1, "Usage: %s parent children...", argv[0]);
+ *
+ *             p.name = argv[1];
+ *             for (i = 2; i < argc, i++) {
+ *                     c = malloc(sizeof(*c));
+ *                     c->name = argv[i];
+ *                     list_add(&p.children, &c->list);
+ *                     p.num_children++;
+ *             }
+ *
+ *             printf("%s has %u children:", p.name, p.num_children);
+ *             list_for_each(&p.children, c, list)
+ *                     printf("%s ", c->name);
+ *             printf("\n");
+ *             return 0;
+ *     }
+ */
+int main(int argc, char *argv[])
+{
+       if (argc != 2)
+               return 1;
+
+       if (strcmp(argv[1], "depends") == 0) {
+               printf("container_of\n");
+               return 0;
+       }
+
+       return 1;
+}

diff --git a/list/list.c b/list/list.c
new file mode 100644 (file)
index 0000000..b72f8f6
--- /dev/null
+++ b/list/list.c
@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "list/list.h"
+
+struct list_head *list_check(struct list_head *h, const char *abortstr)
+{
+       struct list_node *n, *p;
+       int count = 0;
+
+       if (h->n.next == &h->n) {
+               if (h->n.prev != &h->n) {
+                       if (!abortstr)
+                               return NULL;
+                       fprintf(stderr, "%s: prev corrupt in empty %p\n",
+                               abortstr, h);
+                       abort();
+               }
+               return h;
+       }
+
+       for (p = &h->n, n = h->n.next; n != &h->n; p = n, n = n->next) {
+               count++;
+               if (n->prev != p) {
+                       if (!abortstr)
+                               return NULL;
+                       fprintf(stderr,
+                               "%s: prev corrupt in node %p (%u) of %p\n",
+                               abortstr, n, count, h);
+                       abort();
+               }
+       }
+       return h;
+}

diff --git a/list/list.h b/list/list.h
new file mode 100644 (file)
index 0000000..c664d83
--- /dev/null
+++ b/list/list.h
@@ -0,0 +1,253 @@
+#ifndef CCAN_LIST_H
+#define CCAN_LIST_H
+#include <stdbool.h>
+#include "container_of/container_of.h"
+
+/**
+ * struct list_node - an entry in a doubly-linked list
+ * @next: next entry (self if empty)
+ * @prev: previous entry (self if empty)
+ *
+ * This is used as an entry in a linked list.
+ * Example:
+ *     struct child {
+ *             const char *name;
+ *             // Linked list of all us children.
+ *             struct list_node list;
+ *     };
+ */
+struct list_node
+{
+       struct list_node *next, *prev;
+};
+
+/**
+ * struct list_head - the head of a doubly-linked list
+ * @h: the list_head (containing next and prev pointers)
+ *
+ * This is used as the head of a linked list.
+ * Example:
+ *     struct parent {
+ *             const char *name;
+ *             struct list_head children;
+ *             unsigned int num_children;
+ *     };
+ */
+struct list_head
+{
+       struct list_node n;
+};
+
+/**
+ * list_check - check a list for consistency
+ * @h: the list_head
+ * @abortstr: the location to print on aborting, or NULL.
+ *
+ * Because list_nodes have redundant information, consistency checking between
+ * the back and forward links can be done.  This is useful as a debugging check.
+ * If @abortstr is non-NULL, that will be printed in a diagnostic if the list
+ * is inconsistent, and the function will abort.
+ *
+ * Returns the list head if the list is consistent, NULL if not (it
+ * can never return NULL if @abortstr is set).
+ *
+ * Example:
+ *     static void dump_parent(struct parent *p)
+ *     {
+ *             struct child *c;
+ *
+ *             printf("%s (%u children):\n", p->name, parent->num_children);
+ *             list_check(&p->children, "bad child list");
+ *             list_for_each(&p->children, c, list)
+ *                     printf(" -> %s\n", c->name);
+ *     }
+ */
+struct list_head *list_check(struct list_head *h, const char *abortstr);
+
+#ifdef CCAN_LIST_DEBUG
+#define debug_list(h) list_check((h), __func__)
+#else
+#define debug_list(h) (h)
+#endif
+
+/**
+ * list_head_init - initialize a list_head
+ * @h: the list_head to set to the empty list
+ *
+ * Example:
+ *     list_head_init(&parent->children);
+ *     parent->num_children = 0;
+ */
+static inline void list_head_init(struct list_head *h)
+{
+       h->n.next = h->n.prev = &h->n;
+}
+
+/**
+ * LIST_HEAD - define and initalized empty list_head
+ * @name: the name of the list.
+ *
+ * The LIST_HEAD macro defines a list_head and initializes it to an empty
+ * list.  It can be prepended by "static" to define a static list_head.
+ *
+ * Example:
+ *     // Header:
+ *     extern struct list_head my_list;
+ *
+ *     // C file:
+ *     LIST_HEAD(my_list);
+ */
+#define LIST_HEAD(name) \
+       struct list_head name = { { &name.n, &name.n } }
+
+/**
+ * list_add - add an entry at the start of a linked list.
+ * @h: the list_head to add the node to
+ * @n: the list_node to add to the list.
+ *
+ * The list_node does not need to be initialized; it will be overwritten.
+ * Example:
+ *     list_add(&parent->children, &child->list);
+ *     parent->num_children++;
+ */
+static inline void list_add(struct list_head *h, struct list_node *n)
+{
+       n->next = h->n.next;
+       n->prev = &h->n;
+       h->n.next->prev = n;
+       h->n.next = n;
+       (void)debug_list(h);
+}
+
+/**
+ * list_add_tail - add an entry at the end of a linked list.
+ * @h: the list_head to add the node to
+ * @n: the list_node to add to the list.
+ *
+ * The list_node does not need to be initialized; it will be overwritten.
+ * Example:
+ *     list_add_tail(&parent->children, &child->list);
+ *     parent->num_children++;
+ */
+static inline void list_add_tail(struct list_head *h, struct list_node *n)
+{
+       n->next = &h->n;
+       n->prev = h->n.prev;
+       h->n.prev->next = n;
+       h->n.prev = n;
+       (void)debug_list(h);
+}
+
+/**
+ * list_del - delete an entry from a linked list.
+ * @n: the list_node to delete from the list.
+ *
+ * Example:
+ *     list_del(&child->list);
+ *     parent->num_children--;
+ */
+static inline void list_del(struct list_node *n)
+{
+       n->next->prev = n->prev;
+       n->prev->next = n->next;
+       (void)debug_list(n->next);
+#ifdef CCAN_LIST_DEBUG
+       /* Catch use-after-del. */
+       n->next = n->prev = NULL;
+#endif
+}
+
+/**
+ * list_empty - is a list empty?
+ * @h: the list_head
+ *
+ * If the list is empty, returns true.
+ *
+ * Example:
+ *     assert(list_empty(&parent->children) == (parent->num_children == 0));
+ */
+static inline bool list_empty(struct list_head *h)
+{
+       (void)debug_list(h);
+       return h->n.next == &h->n;
+}
+
+/**
+ * list_entry - convert a list_node back into the structure containing it.
+ * @n: the list_node
+ * @type: the type of the entry
+ * @member: the list_node member of the type
+ *
+ * Example:
+ *     struct child *c;
+ *     // First list entry is children.next; convert back to child.
+ *     c = list_entry(parent->children.next, struct child, list);
+ */
+#define list_entry(n, type, member) container_of(n, type, member)
+
+/**
+ * list_top - get the first entry in a list
+ * @h: the list_head
+ * @type: the type of the entry
+ * @member: the list_node member of the type
+ *
+ * If the list is empty, returns NULL.
+ *
+ * Example:
+ *     struct child *first;
+ *     first = list_top(&parent->children, struct child, list);
+ */
+#define list_top(h, type, member) \
+       list_entry(_list_top(h), type, member)  
+
+static inline struct list_node *_list_top(struct list_head *h)
+{
+       (void)debug_list(h);
+       if (list_empty(h))
+               return NULL;
+       return h->n.next;
+}
+
+/**
+ * list_for_each - iterate through a list.
+ * @h: the list_head
+ * @i: the structure containing the list_node
+ * @member: the list_node member of the structure
+ *
+ * This is a convenient wrapper to iterate @i over the entire list.  It's
+ * a for loop, so you can break and continue as normal.
+ *
+ * Example:
+ *     struct child *c;
+ *     list_for_each(&parent->children, c, list)
+ *             printf("Name: %s\n", c->name);
+ */
+#define list_for_each(h, i, member)                                    \
+       for (i = container_of_var(debug_list(h)->n.next, i, member);    \
+            &i->member != &(h)->n;                                     \
+            i = container_of_var(i->member.next, i, member))
+
+/**
+ * list_for_each_safe - iterate through a list, maybe during deletion
+ * @h: the list_head
+ * @i: the structure containing the list_node
+ * @nxt: the structure containing the list_node
+ * @member: the list_node member of the structure
+ *
+ * This is a convenient wrapper to iterate @i over the entire list.  It's
+ * a for loop, so you can break and continue as normal.  The extra variable
+ * @nxt is used to hold the next element, so you can delete @i from the list.
+ *
+ * Example:
+ *     struct child *c, *n;
+ *     list_for_each_safe(&parent->children, c, n, list) {
+ *             list_del(&c->list);
+ *             parent->num_children--;
+ *     }
+ */
+#define list_for_each_safe(h, i, nxt, member)                          \
+       for (i = container_of_var(debug_list(h)->n.next, i, member),    \
+               nxt = container_of_var(i->member.next, i, member);      \
+            &i->member != &(h)->n;                                     \
+            i = nxt, nxt = container_of_var(i->member.next, i, member))
+#endif /* CCAN_LIST_H */

diff --git a/list/test/run.c b/list/test/run.c
new file mode 100644 (file)
index 0000000..2297aed
--- /dev/null
+++ b/list/test/run.c
@@ -0,0 +1,118 @@
+#include "list/list.h"
+#include "tap.h"
+#include "list/list.c"
+
+struct parent {
+       const char *name;
+       struct list_head children;
+       unsigned int num_children;
+};
+
+struct child {
+       const char *name;
+       struct list_node list;
+};
+
+static LIST_HEAD(static_list);
+
+int main(int argc, char *argv[])
+{
+       struct parent parent;
+       struct child c1, c2, c3, *c, *n;
+       unsigned int i;
+
+       plan_tests(41);
+       /* Test LIST_HEAD, list_empty and check_list */
+       ok1(list_empty(&static_list));
+       ok1(list_check(&static_list, NULL));
+
+       parent.num_children = 0;
+       list_head_init(&parent.children);
+       /* Test list_head_init */
+       ok1(list_empty(&parent.children));
+       ok1(list_check(&parent.children, NULL));
+
+       c2.name = "c2";
+       list_add(&parent.children, &c2.list);
+       /* Test list_add and !list_empty. */
+       ok1(!list_empty(&parent.children));
+       ok1(c2.list.next == &parent.children.n);
+       ok1(c2.list.prev == &parent.children.n);
+       ok1(parent.children.n.next == &c2.list);
+       ok1(parent.children.n.prev == &c2.list);
+       /* Test list_check */
+       ok1(list_check(&parent.children, NULL));
+
+       c1.name = "c1";
+       list_add(&parent.children, &c1.list);
+       /* Test list_add and !list_empty. */
+       ok1(!list_empty(&parent.children));
+       ok1(c2.list.next == &parent.children.n);
+       ok1(c2.list.prev == &c1.list);
+       ok1(parent.children.n.next == &c1.list);
+       ok1(parent.children.n.prev == &c2.list);
+       ok1(c1.list.next == &c2.list);
+       ok1(c1.list.prev == &parent.children.n);
+       /* Test list_check */
+       ok1(list_check(&parent.children, NULL));
+
+       c3.name = "c3";
+       list_add_tail(&parent.children, &c3.list);
+       /* Test list_add_tail and !list_empty. */
+       ok1(!list_empty(&parent.children));
+       ok1(parent.children.n.next == &c1.list);
+       ok1(parent.children.n.prev == &c3.list);
+       ok1(c1.list.next == &c2.list);
+       ok1(c1.list.prev == &parent.children.n);
+       ok1(c2.list.next == &c3.list);
+       ok1(c2.list.prev == &c1.list);
+       ok1(c3.list.next == &parent.children.n);
+       ok1(c3.list.prev == &c2.list);
+       /* Test list_check */
+       ok1(list_check(&parent.children, NULL));
+
+       /* Test list_top */
+       ok1(list_top(&parent.children, struct child, list) == &c1);
+
+       /* Test list_for_each. */
+       i = 0;
+       list_for_each(&parent.children, c, list) {
+               switch (i++) {
+               case 0:
+                       ok1(c == &c1);
+                       break;
+               case 1:
+                       ok1(c == &c2);
+                       break;
+               case 2:
+                       ok1(c == &c3);
+                       break;
+               }
+               if (i > 2)
+                       break;
+       }
+       ok1(i == 3);
+
+       /* Test list_for_each_safe and list_del. */
+       i = 0;
+       list_for_each_safe(&parent.children, c, n, list) {
+               switch (i++) {
+               case 0:
+                       ok1(c == &c1);
+                       break;
+               case 1:
+                       ok1(c == &c2);
+                       break;
+               case 2:
+                       ok1(c == &c3);
+                       break;
+               }
+               list_del(&c->list);
+               ok1(list_check(&parent.children, NULL));
+               if (i > 2)
+                       break;
+       }
+       ok1(i == 3);
+       ok1(list_empty(&parent.children));
+       return exit_status();
+}