Small utility collection for dealing with file archives that have dependencies
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pkg-utils/main/cmd/install/tsort.c

79 lines
1.4 KiB

/* SPDX-License-Identifier: ISC */
#include "install.h"
static void remove_dependency(struct pkg_dep_list *list,
struct pkg_dep_node *pkg)
{
struct pkg_dep_node *it;
size_t i;
for (it = list->head; it != NULL; it = it->next) {
for (i = 0; i < it->num_deps; ++i) {
if (it->deps[i] == pkg) {
it->deps[i] = it->deps[it->num_deps - 1];
it->num_deps -= 1;
--i;
}
}
if (it->num_deps == 0 && it->deps != NULL) {
free(it->deps);
it->deps = NULL;
}
}
}
static void append(struct pkg_dep_list *out, struct pkg_dep_node *pkg)
{
if (out->tail == NULL) {
out->head = out->tail = pkg;
} else {
out->tail->next = pkg;
out->tail = pkg;
}
}
static struct pkg_dep_node *remove_no_deps(struct pkg_dep_list *list)
{
struct pkg_dep_node *it = list->head, *prev = NULL;
while (it != NULL && it->num_deps != 0) {
prev = it;
it = it->next;
}
if (it != NULL) {
if (prev == NULL) {
list->head = it->next;
} else {
prev->next = it->next;
}
if (it == list->tail)
list->tail = prev;
}
return it;
}
int sort_by_dependencies(struct pkg_dep_list *list)
{
struct pkg_dep_list result = { NULL, NULL };
struct pkg_dep_node *pkg;
while (list->head != NULL) {
pkg = remove_no_deps(list);
if (pkg == NULL) {
fputs("cycle detected in dependency graph\n", stderr);
pkg_list_cleanup(&result);
return -1;
}
remove_dependency(list, pkg);
append(&result, pkg);
}
*list = result;
return 0;
}