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#include "udpkg.h"
#ifdef DODEPENDS
#include <stdio.h>
#include <stdlib.h>
#include <search.h>
#include <string.h>
#include <ctype.h>
static char **depends_split(const char *dependsstr)
{
static char *dependsvec[DEPENDSMAX];
char *p;
int i = 0;
dependsvec[0] = 0;
if (dependsstr != 0)
{
p = strdup(dependsstr);
while (*p != 0 && *p != '\n')
{
if (*p != ' ')
{
if (*p == ',')
{
*p = 0;
dependsvec[++i] = 0;
}
else if (dependsvec[i] == 0)
dependsvec[i] = p;
}
else
*p = 0; /* eat the space... */
p++;
}
*p = 0;
}
dependsvec[i+1] = 0;
return dependsvec;
}
static void depends_sort_visit(struct package_t **ordered,
struct package_t *pkgs, struct package_t *pkg)
{
/* Topological sort algorithm:
* ordered is the output list, pkgs is the dependency graph, pkg is
* the current node
*
* recursively add all the adjacent nodes to the ordered list, marking
* each one as visited along the way
*
* yes, this algorithm looks a bit odd when all the params have the
* same type :-)
*/
unsigned short i;
/* mark node as processing */
pkg->color = COLOR_GRAY;
/* visit each not-yet-visited node */
for (i = 0; i < pkg->requiredcount; i++)
if (pkg->requiredfor[i]->color == COLOR_WHITE)
depends_sort_visit(ordered, pkgs, pkg->requiredfor[i]);
#if 0
/* add it to the list */
newnode = (struct package_t *)di_malloc(sizeof(struct package_t));
/* make a shallow copy */
*newnode = *pkg;
newnode->next = *ordered;
*ordered = newnode;
#endif
pkg->next = *ordered;
*ordered = pkg;
/* mark node as done */
pkg->color = COLOR_BLACK;
}
static struct package_t *depends_sort(struct package_t *pkgs)
{
/* TODO: it needs to break cycles in the to-be-installed package
* graph... */
struct package_t *ordered = NULL;
struct package_t *pkg;
for (pkg = pkgs; pkg != 0; pkg = pkg->next)
pkg->color = COLOR_WHITE;
for (pkg = pkgs; pkg != 0; pkg = pkg->next)
if (pkg->color == COLOR_WHITE)
depends_sort_visit(&ordered, pkgs, pkg);
/* Leaks the old list... return the new one... */
return ordered;
}
/* resolve package dependencies --
* for each package in the list of packages to be installed, we parse its
* dependency info to determine if the dependent packages are either
* already installed, or are scheduled to be installed. If both tests fail
* than bail.
*
* The algorithm here is O(n^2*m) where n = number of packages to be
* installed and m is the # of dependencies per package. Not a terribly
* efficient algorithm, but given that at any one time you are unlikely
* to install a very large number of packages it doesn't really matter
*/
struct package_t *depends_resolve(struct package_t *pkgs, void *status)
{
struct package_t *pkg, *chk;
struct package_t dependpkg;
char **dependsvec;
int i;
void *found;
for (pkg = pkgs; pkg != 0; pkg = pkg->next)
{
dependsvec = depends_split(pkg->depends);
i = 0;
while (dependsvec[i] != 0)
{
/* Check for dependencies; first look for installed packages */
dependpkg.package = dependsvec[i];
if ((found = tfind(&dependpkg, &status, package_compare)) == 0 ||
((chk = *(struct package_t **)found) &&
(chk->status & (STATUS_FLAGOK | STATUS_STATUSINSTALLED)) !=
(STATUS_FLAGOK | STATUS_STATUSINSTALLED)))
{
/* if it fails, we look through the list of packages we are going to
* install */
for (chk = pkgs; chk != 0; chk = chk->next)
{
if (strcmp(chk->package, dependsvec[i]) == 0 ||
(chk->provides &&
strncmp(chk->provides, dependsvec[i], strlen(dependsvec[i])) == 0))
{
if (chk->requiredcount >= DEPENDSMAX)
{
fprintf(stderr, "Too many dependencies for %s\n",
chk->package);
return 0;
}
if (chk != pkg)
chk->requiredfor[chk->requiredcount++] = pkg;
break;
}
}
if (chk == 0)
{
fprintf(stderr, "%s depends on %s, but it is not going to be installed\n", pkg->package, dependsvec[i]);
return 0;
}
}
i++;
}
}
return depends_sort(pkgs);
}
#endif
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