tlist: typesafe variant of list module.

I chose not to do the "macro creates set of routines" approach, as
we can be almost as safe with a struct containing a pointer to the member
type.

ccan/tlist/LICENSE

@@ -0,0 +1 @@
+../../licenses/LGPL-3

ccan/tlist/_info

@@ -0,0 +1,73 @@
+#include <stdio.h>
+#include <string.h>
+#include "config.h"
+
+/**
+ * tlist - typesafe double linked list routines
+ *
+ * The list header contains routines for manipulating double linked lists;
+ * this extends it so you can create list head types which only accomodate
+ * a specific entry type.
+ *
+ * You use TLIST_TYPE() to define the specific struct tlist_<name>, then use
+ * the tlist_* variants of the various list_* operations.
+ *
+ * Example:
+ *	#include <err.h>
+ *	#include <stdio.h>
+ *	#include <stdlib.h>
+ *	#include <ccan/tlist/tlist.h>
+ *
+ *	// Defines struct tlist_children
+ *	TLIST_TYPE(children, struct child);
+ *	struct parent {
+ *		const char *name;
+ *		struct tlist_children 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];
+ *		tlist_init(&p.children);
+ *		for (i = 2; i < argc; i++) {
+ *			c = malloc(sizeof(*c));
+ *			c->name = argv[i];
+ *			tlist_add(&p.children, c, list);
+ *			p.num_children++;
+ *		}
+ *
+ *		printf("%s has %u children:", p.name, p.num_children);
+ *		tlist_for_each(&p.children, c, list)
+ *			printf("%s ", c->name);
+ *		printf("\n");
+ *		return 0;
+ *	}
+ *
+ * License: LGPL
+ * Author: Rusty Russell <rusty@rustcorp.com.au>
+ */
+int main(int argc, char *argv[])
+{
+	if (argc != 2)
+		return 1;
+
+	if (strcmp(argv[1], "depends") == 0) {
+		printf("ccan/list\n");
+		return 0;
+	}
+
+	return 1;
+}

ccan/tlist/test/compile_fail-tlist_add.c

@@ -0,0 +1,35 @@
+#include <ccan/tlist/tlist.h>
+
+TLIST_TYPE(children, struct child);
+TLIST_TYPE(cousins, struct cousin);
+
+struct child {
+	const char *name;
+	struct list_node list;
+};
+
+struct cousin {
+	const char *name;
+	struct list_node list;
+};
+
+int main(int argc, char *argv[])
+{
+	struct tlist_children children;
+	struct tlist_cousins cousins;
+	struct child child = { "child" };
+	struct cousin cousin = { "cousin" };
+
+	tlist_init(&children);
+	tlist_init(&cousins);
+	tlist_add(&children, &child, list);
+	tlist_add(&cousins, &cousin, list);
+	tlist_del_from(&cousins, &cousin, list);
+#ifdef FAIL
+#if !HAVE_FLEXIBLE_ARRAY_MEMBER
+#error Need flexible array members to check type
+#endif
+	tlist_add(&children, &cousin, list);
+#endif
+	return 0;
+}

ccan/tlist/test/compile_fail-tlist_add_tail.c

@@ -0,0 +1,35 @@
+#include <ccan/tlist/tlist.h>
+
+TLIST_TYPE(children, struct child);
+TLIST_TYPE(cousins, struct cousin);
+
+struct child {
+	const char *name;
+	struct list_node list;
+};
+
+struct cousin {
+	const char *name;
+	struct list_node list;
+};
+
+int main(int argc, char *argv[])
+{
+	struct tlist_children children;
+	struct tlist_cousins cousins;
+	struct child child = { "child" };
+	struct cousin cousin = { "cousin" };
+
+	tlist_init(&children);
+	tlist_init(&cousins);
+	tlist_add(&children, &child, list);
+	tlist_add(&cousins, &cousin, list);
+	tlist_del_from(&cousins, &cousin, list);
+#ifdef FAIL
+#if !HAVE_FLEXIBLE_ARRAY_MEMBER
+#error Need flexible array members to check type
+#endif
+	tlist_add_tail(&children, &cousin, list);
+#endif
+	return 0;
+}

ccan/tlist/test/compile_fail-tlist_del_from.c

@@ -0,0 +1,34 @@
+#include <ccan/tlist/tlist.h>
+
+TLIST_TYPE(children, struct child);
+TLIST_TYPE(cousins, struct cousin);
+
+struct child {
+	const char *name;
+	struct list_node list;
+};
+
+struct cousin {
+	const char *name;
+	struct list_node list;
+};
+
+int main(int argc, char *argv[])
+{
+	struct tlist_children children;
+	struct tlist_cousins cousins;
+	struct child child = { "child" };
+	struct cousin cousin = { "cousin" };
+
+	tlist_init(&children);
+	tlist_init(&cousins);
+	tlist_add(&children, &child, list);
+	tlist_add(&cousins, &cousin, list);
+#ifdef FAIL
+#if !HAVE_FLEXIBLE_ARRAY_MEMBER
+#error Need flexible array members to check type
+#endif
+	tlist_del_from(&children, &cousin, list);
+#endif
+	return 0;
+}

ccan/tlist/test/compile_fail-tlist_for_each.c

@@ -0,0 +1,33 @@
+#include <ccan/tlist/tlist.h>
+
+TLIST_TYPE(children, struct child);
+
+struct child {
+	const char *name;
+	struct list_node list;
+};
+
+struct cousin {
+	const char *name;
+	struct list_node list;
+};
+
+int main(int argc, char *argv[])
+{
+	struct tlist_children children;
+	struct child child = { "child" };
+#ifdef FAIL
+#if !HAVE_FLEXIBLE_ARRAY_MEMBER
+#error Need flexible array members to check type
+#endif
+	struct cousin *c;
+#else
+	struct child *c;
+#endif
+
+	tlist_init(&children);
+	tlist_add(&children, &child, list);
+
+	tlist_for_each(&children, c, list);
+	return 0;
+}

ccan/tlist/test/compile_fail-tlist_for_each_safe.c

@@ -0,0 +1,33 @@
+#include <ccan/tlist/tlist.h>
+
+TLIST_TYPE(children, struct child);
+
+struct child {
+	const char *name;
+	struct list_node list;
+};
+
+struct cousin {
+	const char *name;
+	struct list_node list;
+};
+
+int main(int argc, char *argv[])
+{
+	struct tlist_children children;
+	struct child child = { "child" };
+#ifdef FAIL
+#if !HAVE_FLEXIBLE_ARRAY_MEMBER
+#error Need flexible array members to check type
+#endif
+	struct cousin *c, *n;
+#else
+	struct child *c, *n;
+#endif
+
+	tlist_init(&children);
+	tlist_add(&children, &child, list);
+
+	tlist_for_each_safe(&children, c, n, list);
+	return 0;
+}

ccan/tlist/test/compile_fail-tlist_tail.c

@@ -0,0 +1,35 @@
+#include <ccan/tlist/tlist.h>
+
+TLIST_TYPE(children, struct child);
+
+struct child {
+	const char *name;
+	struct list_node list;
+};
+
+struct cousin {
+	const char *name;
+	struct list_node list;
+};
+
+int main(int argc, char *argv[])
+{
+	struct tlist_children children;
+	struct child child = { "child" };
+	void *c;
+
+	tlist_init(&children);
+	tlist_add(&children, &child, list);
+
+	c = tlist_tail(&children,
+#ifdef FAIL
+#if !HAVE_FLEXIBLE_ARRAY_MEMBER
+#error Need flexible array members to check type
+#endif
+		      struct cousin,
+#else
+		      struct child,
+#endif
+		      list);
+	return 0;
+}

ccan/tlist/test/compile_fail-tlist_top.c

@@ -0,0 +1,35 @@
+#include <ccan/tlist/tlist.h>
+
+TLIST_TYPE(children, struct child);
+
+struct child {
+	const char *name;
+	struct list_node list;
+};
+
+struct cousin {
+	const char *name;
+	struct list_node list;
+};
+
+int main(int argc, char *argv[])
+{
+	struct tlist_children children;
+	struct child child = { "child" };
+	void *c;
+
+	tlist_init(&children);
+	tlist_add(&children, &child, list);
+
+	c = tlist_top(&children,
+#ifdef FAIL
+#if !HAVE_FLEXIBLE_ARRAY_MEMBER
+#error Need flexible array members to check type
+#endif
+		      struct cousin,
+#else
+		      struct child,
+#endif
+		      list);
+	return 0;
+}

ccan/tlist/test/run.c

@@ -0,0 +1,128 @@
+#define CCAN_LIST_DEBUG 1
+#include <ccan/tlist/tlist.h>
+#include <ccan/tap/tap.h>
+
+TLIST_TYPE(children, struct child);
+
+struct parent {
+	const char *name;
+	struct tlist_children children;
+	unsigned int num_children;
+};
+
+struct child {
+	const char *name;
+	struct list_node list;
+};
+
+int main(int argc, char *argv[])
+{
+	struct parent parent;
+	struct child c1, c2, c3, *c, *n;
+	unsigned int i;
+	struct tlist_children tlist = TLIST_INIT(tlist);
+
+	plan_tests(44);
+	/* Test TLIST_INIT, and tlist_empty */
+	ok1(tlist_empty(&tlist));
+	ok1(tlist_check(&tlist, NULL));
+
+	parent.num_children = 0;
+	tlist_init(&parent.children);
+	/* Test tlist_init */
+	ok1(tlist_empty(&parent.children));
+	ok1(tlist_check(&parent.children, NULL));
+
+	c2.name = "c2";
+	tlist_add(&parent.children, &c2, list);
+	/* Test tlist_add and !tlist_empty. */
+	ok1(!tlist_empty(&parent.children));
+	ok1(c2.list.next == &parent.children.raw.n);
+	ok1(c2.list.prev == &parent.children.raw.n);
+	ok1(parent.children.raw.n.next == &c2.list);
+	ok1(parent.children.raw.n.prev == &c2.list);
+	/* Test tlist_check */
+	ok1(tlist_check(&parent.children, NULL));
+
+	c1.name = "c1";
+	tlist_add(&parent.children, &c1, list);
+	/* Test list_add and !list_empty. */
+	ok1(!tlist_empty(&parent.children));
+	ok1(c2.list.next == &parent.children.raw.n);
+	ok1(c2.list.prev == &c1.list);
+	ok1(parent.children.raw.n.next == &c1.list);
+	ok1(parent.children.raw.n.prev == &c2.list);
+	ok1(c1.list.next == &c2.list);
+	ok1(c1.list.prev == &parent.children.raw.n);
+	/* Test tlist_check */
+	ok1(tlist_check(&parent.children, NULL));
+
+	c3.name = "c3";
+	tlist_add_tail(&parent.children, &c3, list);
+	/* Test list_add_tail and !list_empty. */
+	ok1(!tlist_empty(&parent.children));
+	ok1(parent.children.raw.n.next == &c1.list);
+	ok1(parent.children.raw.n.prev == &c3.list);
+	ok1(c1.list.next == &c2.list);
+	ok1(c1.list.prev == &parent.children.raw.n);
+	ok1(c2.list.next == &c3.list);
+	ok1(c2.list.prev == &c1.list);
+	ok1(c3.list.next == &parent.children.raw.n);
+	ok1(c3.list.prev == &c2.list);
+	/* Test tlist_check */
+	ok1(tlist_check(&parent.children, NULL));
+
+	/* Test tlist_top */
+	ok1(tlist_top(&parent.children, struct child, list) == &c1);
+
+	/* Test list_tail */
+	ok1(tlist_tail(&parent.children, struct child, list) == &c3);
+
+	/* Test tlist_for_each. */
+	i = 0;
+	tlist_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 tlist_for_each_safe, tlist_del and tlist_del_from. */
+	i = 0;
+	tlist_for_each_safe(&parent.children, c, n, list) {
+		switch (i++) {
+		case 0:
+			ok1(c == &c1);	
+			tlist_del(c, list);
+			break;
+		case 1:
+			ok1(c == &c2);
+			tlist_del_from(&parent.children, c, list);
+			break;
+		case 2:
+			ok1(c == &c3);
+			tlist_del_from(&parent.children, c, list);
+			break;
+		}
+		ok1(tlist_check(&parent.children, NULL));
+		if (i > 2)
+			break;
+	}
+	ok1(i == 3);
+	ok1(tlist_empty(&parent.children));
+
+	/* Test list_top/list_tail on empty list. */
+	ok1(tlist_top(&parent.children, struct child, list) == NULL);
+	ok1(tlist_tail(&parent.children, struct child, list) == NULL);
+	return exit_status();
+}

ccan/tlist/tlist.h

@@ -0,0 +1,252 @@
+#ifndef CCAN_TLIST_H
+#define CCAN_TLIST_H
+#include <ccan/list/list.h>
+
+#if HAVE_FLEXIBLE_ARRAY_MEMBER
+/**
+ * TLIST_TYPE - declare a typed list type (struct tlist)
+ * @suffix: the name to use (struct tlist_@suffix)
+ * @type: the type the list will contain (void for any type)
+ *
+ * This declares a structure "struct tlist_@suffix" to use for
+ * lists containing this type.  The actual list can be accessed using
+ * ".raw" or tlist_raw().
+ *
+ * Example:
+ *	// Defines struct tlist_children
+ *	TLIST_TYPE(children, struct child);
+ *	struct parent {
+ *		const char *name;
+ *		struct tlist_children children;
+ *		unsigned int num_children;
+ *	};
+ *
+ *	struct child {
+ *		const char *name;
+ *		struct list_node list;
+ *	};
+ */
+#define TLIST_TYPE(suffix, type)					\
+	struct tlist_##suffix {						\
+		struct list_head raw;					\
+		const type *tcheck[];					\
+	}
+
+/**
+ * tlist_raw - access the raw list inside a typed list head.
+ * @h: the head of the typed list (struct tlist_@suffix)
+ * @test_var: a pointer to the expected element type.
+ *
+ * This elaborate macro usually causes the compiler to emit a warning
+ * if the variable is of an unexpected type.  It is used internally
+ * where we need to access the raw underlying list.
+ */
+#define tlist_raw(h, test_var) \
+	(sizeof((h)->tcheck[0] == (test_var)) ? &(h)->raw : &(h)->raw)
+#else
+#define TLIST_TYPE(suffix, type)					\
+	struct tlist_##suffix {						\
+		struct list_head raw;					\
+	}
+#define tlist_raw(h, test_var) (&(h)->raw)
+#endif
+
+/**
+ * TLIST_INIT - initalizer for an empty tlist
+ * @name: the name of the list.
+ *
+ * Explicit initializer for an empty list.
+ *
+ * See also:
+ *	tlist_init()
+ *
+ * Example:
+ *	static struct tlist_children my_list = TLIST_INIT(my_list);
+ */
+#define TLIST_INIT(name) { LIST_HEAD_INIT(name.raw) }
+
+/**
+ * tlist_check - check head of a list for consistency
+ * @h: the tlist_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 non-NULL if the list is consistent, NULL otherwise (it
+ * can never return NULL if @abortstr is set).
+ *
+ * See also: list_check()
+ *
+ * Example:
+ *	static void dump_parent(struct parent *p)
+ *	{
+ *		struct child *c;
+ *
+ *		printf("%s (%u children):\n", p->name, p->num_children);
+ *		tlist_check(&p->children, "bad child list");
+ *		tlist_for_each(&p->children, c, list)
+ *			printf(" -> %s\n", c->name);
+ *	}
+ */
+#define tlist_check(h, abortstr) \
+	list_check(&(h)->raw, (abortstr))
+
+/**
+ * tlist_init - initialize a tlist
+ * @h: the tlist to set to the empty list
+ *
+ * Example:
+ *	...
+ *	struct parent *parent = malloc(sizeof(*parent));
+ *
+ *	tlist_init(&parent->children);
+ *	parent->num_children = 0;
+ */
+#define tlist_init(h) list_head_init(&(h)->raw)
+
+/**
+ * tlist_add - add an entry at the start of a linked list.
+ * @h: the tlist to add the node to
+ * @n: the entry to add to the list.
+ * @member: the member of n to add to the list.
+ *
+ * The entry's list_node does not need to be initialized; it will be
+ * overwritten.
+ * Example:
+ *	struct child *child = malloc(sizeof(*child));
+ *
+ *	child->name = "marvin";
+ *	tlist_add(&parent->children, child, list);
+ *	parent->num_children++;
+ */
+#define tlist_add(h, n, member) list_add(tlist_raw((h), (n)), &(n)->member)
+
+/**
+ * tlist_add_tail - add an entry at the end of a linked list.
+ * @h: the tlist to add the node to
+ * @n: the entry to add to the list.
+ * @member: the member of n to add to the list.
+ *
+ * The list_node does not need to be initialized; it will be overwritten.
+ * Example:
+ *	tlist_add_tail(&parent->children, child, list);
+ *	parent->num_children++;
+ */
+#define tlist_add_tail(h, n, member) \
+	list_add_tail(tlist_raw((h), (n)), &(n)->member)
+
+/**
+ * tlist_del_from - delete an entry from a linked list.
+ * @h: the tlist @n is in
+ * @n: the entry to delete
+ * @member: the member of n to remove from the list.
+ *
+ * This explicitly indicates which list a node is expected to be in,
+ * which is better documentation and can catch more bugs.
+ *
+ * Note that this leaves @n->@member in an undefined state; it
+ * can be added to another list, but not deleted again.
+ *
+ * See also: tlist_del()
+ *
+ * Example:
+ *	tlist_del_from(&parent->children, child, list);
+ *	parent->num_children--;
+ */
+#define tlist_del_from(h, n, member) \
+	list_del_from(tlist_raw((h), (n)), &(n)->member)
+
+/**
+ * tlist_del - delete an entry from an unknown linked list.
+ * @n: the entry to delete from the list.
+ * @member: the member of @n which is in the list.
+ *
+ * Example:
+ *	tlist_del(child, list);
+ *	parent->num_children--;
+ */
+#define tlist_del(n, member) \
+	list_del(&(n)->member)
+
+/**
+ * tlist_empty - is a list empty?
+ * @h: the tlist
+ *
+ * If the list is empty, returns true.
+ *
+ * Example:
+ *	assert(tlist_empty(&parent->children) == (parent->num_children == 0));
+ */
+#define tlist_empty(h) list_empty(&(h)->raw)
+
+/**
+ * tlist_top - get the first entry in a list
+ * @h: the tlist
+ * @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 = tlist_top(&parent->children, struct child, list);
+ */
+#define tlist_top(h, type, member) \
+	list_top(tlist_raw((h), (type *)NULL), type, member)
+
+/**
+ * tlist_tail - get the last entry in a list
+ * @h: the tlist
+ * @type: the type of the entry
+ * @member: the list_node member of the type
+ *
+ * If the list is empty, returns NULL.
+ *
+ * Example:
+ *	struct child *last;
+ *	last = tlist_tail(&parent->children, struct child, list);
+ */
+#define tlist_tail(h, type, member) \
+	list_tail(tlist_raw((h), (type *)NULL), type, member)
+
+/**
+ * tlist_for_each - iterate through a list.
+ * @h: the tlist
+ * @i: an iterator of suitable type for this list.
+ * @member: the list_node member of @i
+ *
+ * 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:
+ *	tlist_for_each(&parent->children, child, list)
+ *		printf("Name: %s\n", child->name);
+ */
+#define tlist_for_each(h, i, member)					\
+	list_for_each(tlist_raw((h), (i)), (i), member)
+
+/**
+ * tlist_for_each_safe - iterate through a list, maybe during deletion
+ * @h: the tlist
+ * @i: an iterator of suitable type for this list.
+ * @nxt: another iterator to store the next entry.
+ * @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 *next;
+ *	tlist_for_each_safe(&parent->children, child, next, list) {
+ *		tlist_del(child, list);
+ *		parent->num_children--;
+ *	}
+ */
+#define tlist_for_each_safe(h, i, nxt, member)				\
+	list_for_each_safe(tlist_raw((h), (i)), (i), (nxt), member)
+
+#endif /* CCAN_TLIST_H */