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/* Licensed under LGPLv2.1+ - see LICENSE file for details */
#include <ccan/dgraph/dgraph.h>
#include <stdlib.h>
#include <stdio.h>
void dgraph_init_node(struct dgraph_node *n)
{
tlist_init(&n->edge[DGRAPH_FROM]);
tlist_init(&n->edge[DGRAPH_TO]);
}
static void free_edge(struct dgraph_edge *e)
{
tlist_del_from(&e->n[DGRAPH_FROM]->edge[DGRAPH_FROM],
e, list[DGRAPH_FROM]);
tlist_del_from(&e->n[DGRAPH_TO]->edge[DGRAPH_TO],
e, list[DGRAPH_TO]);
free(e);
}
void dgraph_clear_node(struct dgraph_node *n)
{
struct dgraph_edge *e;
unsigned int i;
(void)dgraph_debug(n);
for (i = DGRAPH_FROM; i <= DGRAPH_TO; i++) {
while ((e = tlist_top(&n->edge[i], list[i])) != NULL) {
assert(e->n[i] == n);
free_edge(e);
}
}
}
void dgraph_add_edge(struct dgraph_node *from, struct dgraph_node *to)
{
struct dgraph_edge *e = malloc(sizeof(*e));
(void)dgraph_debug(from);
(void)dgraph_debug(to);
e->n[DGRAPH_FROM] = from;
e->n[DGRAPH_TO] = to;
tlist_add(&from->edge[DGRAPH_FROM], e, list[DGRAPH_FROM]);
tlist_add(&to->edge[DGRAPH_TO], e, list[DGRAPH_TO]);
}
bool dgraph_del_edge(struct dgraph_node *from, struct dgraph_node *to)
{
struct dgraph_edge *e, *next;
(void)dgraph_debug(from);
(void)dgraph_debug(to);
dgraph_for_each_edge_safe(from, e, next, DGRAPH_FROM) {
if (e->n[DGRAPH_TO] == to) {
free_edge(e);
return true;
}
}
return false;
}
static bool traverse_depth_first(struct dgraph_node *n,
enum dgraph_dir dir,
bool (*fn)(struct dgraph_node *, void *),
const void *data)
{
struct dgraph_edge *e, *next;
/* dgraph_for_each_edge_safe, without dgraph_debug() */
tlist_for_each_safe(&n->edge[dir], e, next, list[dir]) {
if (!traverse_depth_first(e->n[!dir], dir, fn, data))
return false;
}
return fn(n, (void *)data);
}
void dgraph_traverse(const struct dgraph_node *n,
enum dgraph_dir dir,
bool (*fn)(struct dgraph_node *, void *),
const void *data)
{
struct dgraph_edge *e, *next;
/* dgraph_for_each_edge_safe, without dgraph_debug() */
tlist_for_each_safe(&n->edge[dir], e, next, list[dir]) {
if (!traverse_depth_first(e->n[!dir], dir, fn, data))
break;
}
}
struct check_info {
const struct dgraph_node *ret;
const char *abortstr;
};
static bool find_backedge(const struct dgraph_node *from,
const struct dgraph_node *to,
enum dgraph_dir dir)
{
struct dgraph_edge *e;
tlist_for_each(&from->edge[dir], e, list[dir]) {
if (e->n[!dir] == to)
return true;
}
return false;
}
static bool dgraph_check_node(struct dgraph_node *n, void *info_)
{
struct check_info *info = info_;
unsigned int dir;
struct dgraph_edge *e;
for (dir = DGRAPH_FROM; dir <= DGRAPH_TO; dir++) {
/* First, check edges list. */
if (!tlist_check(&n->edge[dir], info->abortstr)) {
info->ret = NULL;
return false;
}
/* dgraph_for_each_edge() without check! */
tlist_for_each(&n->edge[dir], e, list[dir]) {
if (e->n[dir] == n) {
if (find_backedge(e->n[!dir], n, !dir))
continue;
if (info->abortstr) {
fprintf(stderr,
"%s: node %p %s edge doesnt"
" point back to %p\n",
info->abortstr, e->n[!dir],
!dir == DGRAPH_FROM
? "DGRAPH_FROM" : "DGRAPH_TO",
n);
abort();
}
info->ret = NULL;
return false;
}
if (info->abortstr) {
fprintf(stderr,
"%s: node %p %s edge %p points"
" to %p\n",
info->abortstr, n,
dir == DGRAPH_FROM
? "DGRAPH_FROM" : "DGRAPH_TO",
e, e->n[dir]);
abort();
}
info->ret = NULL;
return false;
}
}
return true;
}
struct dgraph_node *dgraph_check(const struct dgraph_node *n,
const char *abortstr)
{
struct check_info info;
/* This gets set to NULL by dgraph_check_node on failure. */
info.ret = n;
info.abortstr = abortstr;
dgraph_check_node((struct dgraph_node *)info.ret, &info);
if (info.ret)
dgraph_traverse(n, DGRAPH_FROM, dgraph_check_node, &info);
if (info.ret)
dgraph_traverse(n, DGRAPH_TO, dgraph_check_node, &info);
return (void *)info.ret;
}
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