1 files changed, 251 insertions, 200 deletions

diff --git a/lib/libalpm/deps.c b/lib/libalpm/deps.c
index b967243d..ab027074 100644
--- a/lib/libalpm/deps.c
+++ b/lib/libalpm/deps.c
@@ -30,37 +30,21 @@
 #include "alpm_list.h"
 #include "util.h"
 #include "log.h"
-#include "error.h"
+#include "graph.h"
 #include "package.h"
 #include "db.h"
 #include "cache.h"
 #include "handle.h"
 
-static pmgraph_t *_alpm_graph_new(void)
+void _alpm_dep_free(pmdepend_t *dep)
 {
-	pmgraph_t *graph = NULL;
-
-	MALLOC(graph, sizeof(pmgraph_t), RET_ERR(PM_ERR_MEMORY, NULL));
-
-	if(graph) {
-		graph->state = 0;
-		graph->data = NULL;
-		graph->parent = NULL;
-		graph->children = NULL;
-		graph->childptr = NULL;
-	}
-	return(graph);
-}
-
-static void _alpm_graph_free(void *data)
-{
-	pmgraph_t *graph = data;
-	alpm_list_free(graph->children);
-	free(graph);
+	FREE(dep->name);
+	FREE(dep->version);
+	FREE(dep);
 }
 
-pmdepmissing_t *_alpm_depmiss_new(const char *target, pmdepmod_t depmod,
-		const char *depname, const char *depversion)
+pmdepmissing_t *_alpm_depmiss_new(const char *target, pmdepend_t *dep,
+		const char *causingpkg)
 {
 	pmdepmissing_t *miss;
 
@@ -68,26 +52,29 @@ pmdepmissing_t *_alpm_depmiss_new(const char *target, pmdepmod_t depmod,
 
 	MALLOC(miss, sizeof(pmdepmissing_t), RET_ERR(PM_ERR_MEMORY, NULL));
 
-	strncpy(miss->target, target, PKG_NAME_LEN);
-	miss->depend.mod = depmod;
-	strncpy(miss->depend.name, depname, PKG_NAME_LEN);
-	if(depversion) {
-		strncpy(miss->depend.version, depversion, PKG_VERSION_LEN);
-	} else {
-		miss->depend.version[0] = 0;
-	}
+	STRDUP(miss->target, target, RET_ERR(PM_ERR_MEMORY, NULL));
+	miss->depend = _alpm_dep_dup(dep);
+	STRDUP(miss->causingpkg, causingpkg, RET_ERR(PM_ERR_MEMORY, NULL));
 
 	return(miss);
 }
 
+void _alpm_depmiss_free(pmdepmissing_t *miss)
+{
+	_alpm_dep_free(miss->depend);
+	FREE(miss->target);
+	FREE(miss->causingpkg);
+	FREE(miss);
+}
+
 /* Convert a list of pmpkg_t * to a graph structure,
  * with a edge for each dependency.
  * Returns a list of vertices (one vertex = one package)
  * (used by alpm_sortbydeps)
  */
-static alpm_list_t *_alpm_graph_init(alpm_list_t *targets)
+static alpm_list_t *dep_graph_init(alpm_list_t *targets)
 {
-	alpm_list_t *i, *j, *k;
+	alpm_list_t *i, *j;
 	alpm_list_t *vertices = NULL;
 	/* We create the vertices */
 	for(i = targets; i; i = i->next) {
@@ -104,12 +91,7 @@ static alpm_list_t *_alpm_graph_init(alpm_list_t *targets)
 		for(j = vertices; j; j = j->next) {
 			pmgraph_t *vertex_j = j->data;
 			pmpkg_t *p_j = vertex_j->data;
-			int child = 0;
-			for(k = alpm_pkg_get_depends(p_i); k && !child; k = k->next) {
-				pmdepend_t *depend = k->data;
-				child = alpm_depcmp(p_j, depend);
-			}
-			if(child) {
+			if(_alpm_dep_edge(p_i, p_j)) {
 				vertex_i->children =
 					alpm_list_add(vertex_i->children, vertex_j);
 			}
@@ -121,20 +103,19 @@ static alpm_list_t *_alpm_graph_init(alpm_list_t *targets)
 
 /* Re-order a list of target packages with respect to their dependencies.
  *
- * Example (PM_TRANS_TYPE_ADD):
+ * Example (reverse == 0):
  *   A depends on C
  *   B depends on A
  *   Target order is A,B,C,D
  *
  *   Should be re-ordered to C,A,B,D
  *
- * mode should be either PM_TRANS_TYPE_ADD or PM_TRANS_TYPE_REMOVE.  This
- * affects the dependency order sortbydeps() will use.
+ * if reverse is > 0, the dependency order will be reversed.
  *
  * This function returns the new alpm_list_t* target list.
  *
  */
-alpm_list_t *_alpm_sortbydeps(alpm_list_t *targets, pmtranstype_t mode)
+alpm_list_t *_alpm_sortbydeps(alpm_list_t *targets, int reverse)
 {
 	alpm_list_t *newtargs = NULL;
 	alpm_list_t *vertices = NULL;
@@ -149,7 +130,7 @@ alpm_list_t *_alpm_sortbydeps(alpm_list_t *targets, pmtranstype_t mode)
 
 	_alpm_log(PM_LOG_DEBUG, "started sorting dependencies\n");
 
-	vertices = _alpm_graph_init(targets);
+	vertices = dep_graph_init(targets);
 
 	vptr = vertices;
 	vertex = vertices->data;
@@ -169,7 +150,7 @@ alpm_list_t *_alpm_sortbydeps(alpm_list_t *targets, pmtranstype_t mode)
 				pmpkg_t *vertexpkg = vertex->data;
 				pmpkg_t *childpkg = nextchild->data;
 				_alpm_log(PM_LOG_WARNING, _("dependency cycle detected:\n"));
-				if(mode == PM_TRANS_TYPE_REMOVE) {
+				if(reverse) {
 					_alpm_log(PM_LOG_WARNING, _("%s will be removed after its %s dependency\n"), vertexpkg->name, childpkg->name);
 				} else {
 					_alpm_log(PM_LOG_WARNING, _("%s will be installed before its %s dependency\n"), vertexpkg->name, childpkg->name);
@@ -194,8 +175,8 @@ alpm_list_t *_alpm_sortbydeps(alpm_list_t *targets, pmtranstype_t mode)
 
 	_alpm_log(PM_LOG_DEBUG, "sorting dependencies finished\n");
 
-	if(mode == PM_TRANS_TYPE_REMOVE) {
-		/* we're removing packages, so reverse the order */
+	if(reverse) {
+		/* reverse the order */
 		alpm_list_t *tmptargs = alpm_list_reverse(newtargs);
 		/* free the old one */
 		alpm_list_free(newtargs);
@@ -208,10 +189,68 @@ alpm_list_t *_alpm_sortbydeps(alpm_list_t *targets, pmtranstype_t mode)
 	return(newtargs);
 }
 
-/* Little helper function for alpm_list_find */
-static int satisfycmp(const void *pkg, const void *depend)
+pmpkg_t *_alpm_find_dep_satisfier(alpm_list_t *pkgs, pmdepend_t *dep)
+{
+	alpm_list_t *i;
+
+	for(i = pkgs; i; i = alpm_list_next(i)) {
+		pmpkg_t *pkg = i->data;
+		if(alpm_depcmp(pkg, dep)) {
+			return(pkg);
+		}
+	}
+	return(NULL);
+}
+
+alpm_list_t *_alpm_find_dep_satisfiers(alpm_list_t *pkgs, pmdepend_t *dep)
+{
+	alpm_list_t *i, *ret = NULL;
+
+	for(i = pkgs; i; i = alpm_list_next(i)) {
+		pmpkg_t *pkg = i->data;
+		if(alpm_depcmp(pkg, dep)) {
+			ret = alpm_list_add(ret, pkg);
+		}
+	}
+	return(ret);
+}
+
+/** Find packages in a list that provide a given package.
+ * @param pkgs an alpm_list_t* of package to search
+ * @param pkgname the name of the package
+ * @return an alpm_list_t* of packages that provide pkgname
+ */
+alpm_list_t SYMEXPORT *alpm_find_pkg_satisfiers(alpm_list_t *pkgs, const char *pkgname)
 {
-	return(!alpm_depcmp((pmpkg_t*) pkg, (pmdepend_t*) depend));
+	pmdepend_t *dep = _alpm_splitdep(pkgname);
+	alpm_list_t *res = _alpm_find_dep_satisfiers(pkgs, dep);
+	_alpm_dep_free(dep);
+	return(res);
+}
+
+/** Checks dependencies and returns missing ones in a list.
+ * Dependencies can include versions with depmod operators.
+ * @param db pointer to the local package database
+ * @param targets an alpm_list_t* of dependencies strings to satisfy
+ * @return an alpm_list_t* of missing dependencies strings
+ */
+alpm_list_t SYMEXPORT *alpm_deptest(pmdb_t *db, alpm_list_t *targets)
+{
+	alpm_list_t *i, *ret = NULL;
+
+	for(i = targets; i; i = alpm_list_next(i)) {
+		pmdepend_t *dep;
+		char *target;
+
+		target = alpm_list_getdata(i);
+		dep = _alpm_splitdep(target);
+
+		if(!_alpm_find_dep_satisfier(_alpm_db_get_pkgcache(db), dep)) {
+			ret = alpm_list_add(ret, target);
+		}
+		_alpm_dep_free(dep);
+	}
+	return(ret);
 }
 
 /** Checks dependencies and returns missing ones in a list.
@@ -257,15 +296,14 @@ alpm_list_t SYMEXPORT *alpm_checkdeps(pmdb_t *db, int reversedeps,
 			pmdepend_t *depend = j->data;
 			/* 1. we check the upgrade list */
 			/* 2. we check database for untouched satisfying packages */
-			if(!alpm_list_find(upgrade, depend, satisfycmp) &&
-			   !alpm_list_find(dblist, depend, satisfycmp)) {
+			if(!_alpm_find_dep_satisfier(upgrade, depend) &&
+			   !_alpm_find_dep_satisfier(dblist, depend)) {
 				/* Unsatisfied dependency in the upgrade list */
 				char *missdepstring = alpm_dep_get_string(depend);
 				_alpm_log(PM_LOG_DEBUG, "checkdeps: missing dependency '%s' for package '%s'\n",
 						missdepstring, alpm_pkg_get_name(tp));
 				free(missdepstring);
-				miss = _alpm_depmiss_new(alpm_pkg_get_name(tp), depend->mod,
-						depend->name, depend->version);
+				miss = _alpm_depmiss_new(alpm_pkg_get_name(tp), depend, "");
 				baddeps = alpm_list_add(baddeps, miss);
 			}
 		}
@@ -278,18 +316,18 @@ alpm_list_t SYMEXPORT *alpm_checkdeps(pmdb_t *db, int reversedeps,
 			pmpkg_t *lp = i->data;
 			for(j = alpm_pkg_get_depends(lp); j; j = j->next) {
 				pmdepend_t *depend = j->data;
+				pmpkg_t *causingpkg = _alpm_find_dep_satisfier(modified, depend);
 				/* we won't break this depend, if it is already broken, we ignore it */
 				/* 1. check upgrade list for satisfiers */
 				/* 2. check dblist for satisfiers */
-				if(alpm_list_find(modified, depend, satisfycmp) &&
-				   !alpm_list_find(upgrade, depend, satisfycmp) &&
-				   !alpm_list_find(dblist, depend, satisfycmp)) {
+				if(causingpkg &&
+				   !_alpm_find_dep_satisfier(upgrade, depend) &&
+				   !_alpm_find_dep_satisfier(dblist, depend)) {
 					char *missdepstring = alpm_dep_get_string(depend);
 					_alpm_log(PM_LOG_DEBUG, "checkdeps: transaction would break '%s' dependency of '%s'\n",
 							missdepstring, alpm_pkg_get_name(lp));
 					free(missdepstring);
-					miss = _alpm_depmiss_new(lp->name, depend->mod,
-							depend->name, depend->version);
+					miss = _alpm_depmiss_new(lp->name, depend, alpm_pkg_get_name(causingpkg));
 					baddeps = alpm_list_add(baddeps, miss);
 				}
 			}
@@ -309,7 +347,7 @@ static int dep_vercmp(const char *version1, pmdepmod_t mod,
 	if(mod == PM_DEP_MOD_ANY) {
 		equal = 1;
 	} else {
-		int cmp = _alpm_versioncmp(version1, version2);
+		int cmp = alpm_pkg_vercmp(version1, version2);
 		switch(mod) {
 			case PM_DEP_MOD_EQ: equal = (cmp == 0); break;
 			case PM_DEP_MOD_GE: equal = (cmp >= 0); break;
@@ -356,7 +394,7 @@ int SYMEXPORT alpm_depcmp(pmpkg_t *pkg, pmdepend_t *dep)
 	return(satisfy);
 }
 
-pmdepend_t SYMEXPORT *alpm_splitdep(const char *depstring)
+pmdepend_t *_alpm_splitdep(const char *depstring)
 {
 	pmdepend_t *depend;
 	char *ptr = NULL;
@@ -365,9 +403,9 @@ pmdepend_t SYMEXPORT *alpm_splitdep(const char *depstring)
 	if(depstring == NULL) {
 		return(NULL);
 	}
-	newstr = strdup(depstring);
+	STRDUP(newstr, depstring, RET_ERR(PM_ERR_MEMORY, NULL));
 
-	MALLOC(depend, sizeof(pmdepend_t), return(NULL));
+	CALLOC(depend, 1, sizeof(pmdepend_t), RET_ERR(PM_ERR_MEMORY, NULL));
 
 	/* Find a version comparator if one exists. If it does, set the type and
 	 * increment the ptr accordingly so we can copy the right strings. */
@@ -391,25 +429,36 @@ pmdepend_t SYMEXPORT *alpm_splitdep(const char *depstring)
 		depend->mod = PM_DEP_MOD_GT;
 		*ptr = '\0';
 		ptr += 1;
-
 	} else {
-		/* no version specified - copy in the name and return it */
+		/* no version specified - copy the name and return it */
 		depend->mod = PM_DEP_MOD_ANY;
-		strncpy(depend->name, newstr, PKG_NAME_LEN);
-		depend->version[0] = '\0';
+		STRDUP(depend->name, newstr, RET_ERR(PM_ERR_MEMORY, NULL));
+		depend->version = NULL;
 		free(newstr);
 		return(depend);
 	}
 
 	/* if we get here, we have a version comparator, copy the right parts
 	 * to the right places */
-	strncpy(depend->name, newstr, PKG_NAME_LEN);
-	strncpy(depend->version, ptr, PKG_VERSION_LEN);
+	STRDUP(depend->name, newstr, RET_ERR(PM_ERR_MEMORY, NULL));
+	STRDUP(depend->version, ptr, RET_ERR(PM_ERR_MEMORY, NULL));
 	free(newstr);
 
 	return(depend);
 }
 
+pmdepend_t *_alpm_dep_dup(const pmdepend_t *dep)
+{
+	pmdepend_t *newdep;
+	CALLOC(newdep, 1, sizeof(pmdepend_t), RET_ERR(PM_ERR_MEMORY, NULL));
+
+	STRDUP(newdep->name, dep->name, RET_ERR(PM_ERR_MEMORY, NULL));
+	STRDUP(newdep->version, dep->version, RET_ERR(PM_ERR_MEMORY, NULL));
+	newdep->mod = dep->mod;
+
+	return(newdep);
+}
+
 /* These parameters are messy. We check if this package, given a list of
  * targets and a db is safe to remove. We do NOT remove it if it is in the
  * target list, or if if the package was explictly installed and
@@ -417,9 +466,9 @@ pmdepend_t SYMEXPORT *alpm_splitdep(const char *depstring)
 static int can_remove_package(pmdb_t *db, pmpkg_t *pkg, alpm_list_t *targets,
 		int include_explicit)
 {
-	alpm_list_t *i, *requiredby;
+	alpm_list_t *i;
 
-	if(_alpm_pkg_find(alpm_pkg_get_name(pkg), targets)) {
+	if(_alpm_pkg_find(targets, alpm_pkg_get_name(pkg))) {
 		return(0);
 	}
 
@@ -439,15 +488,12 @@ static int can_remove_package(pmdb_t *db, pmpkg_t *pkg, alpm_list_t *targets,
 	 * if checkdeps detected it would break something */
 
 	/* see if other packages need it */
-	requiredby = alpm_pkg_compute_requiredby(pkg);
-	for(i = requiredby; i; i = i->next) {
-		pmpkg_t *reqpkg = _alpm_db_get_pkgfromcache(db, i->data);
-		if(reqpkg && !_alpm_pkg_find(alpm_pkg_get_name(reqpkg), targets)) {
-			FREELIST(requiredby);
+	for(i = _alpm_db_get_pkgcache(db); i; i = i->next) {
+		pmpkg_t *lpkg = i->data;
+		if(_alpm_dep_edge(lpkg, pkg) && !_alpm_pkg_find(targets, lpkg->name)) {
 			return(0);
 		}
 	}
-	FREELIST(requiredby);
 
 	/* it's ok to remove */
 	return(1);
@@ -465,7 +511,7 @@ static int can_remove_package(pmdb_t *db, pmpkg_t *pkg, alpm_list_t *targets,
  */
 void _alpm_recursedeps(pmdb_t *db, alpm_list_t *targs, int include_explicit)
 {
-	alpm_list_t *i, *j, *k;
+	alpm_list_t *i, *j;
 
 	ALPM_LOG_FUNC;
 
@@ -475,159 +521,151 @@ void _alpm_recursedeps(pmdb_t *db, alpm_list_t *targs, int include_explicit)
 
 	for(i = targs; i; i = i->next) {
 		pmpkg_t *pkg = i->data;
-		for(j = alpm_pkg_get_depends(pkg); j; j = j->next) {
-			pmdepend_t *depend = j->data;
+		for(j = _alpm_db_get_pkgcache(db); j; j = j->next) {
+			pmpkg_t *deppkg = j->data;
+			if(_alpm_dep_edge(pkg, deppkg)
+					&& can_remove_package(db, deppkg, targs, include_explicit)) {
+				_alpm_log(PM_LOG_DEBUG, "adding '%s' to the targets\n",
+						alpm_pkg_get_name(deppkg));
+				/* add it to the target list */
+				targs = alpm_list_add(targs, _alpm_pkg_dup(deppkg));
+			}
+		}
+	}
+}
 
-			for(k = _alpm_db_get_pkgcache(db); k; k = k->next) {
-				pmpkg_t *deppkg = k->data;
-				if(alpm_depcmp(deppkg,depend)
-						&& can_remove_package(db, deppkg, targs, include_explicit)) {
-					_alpm_log(PM_LOG_DEBUG, "adding '%s' to the targets\n",
-							alpm_pkg_get_name(deppkg));
-						/* add it to the target list */
-					targs = alpm_list_add(targs, _alpm_pkg_dup(deppkg));
+/* helper function for resolvedeps: search for dep satisfier in dbs */
+pmpkg_t *_alpm_resolvedep(pmdepend_t *dep, alpm_list_t *dbs, alpm_list_t *excluding, pmpkg_t *tpkg)
+{
+	alpm_list_t *i, *j;
+	/* 1. literals */
+	for(i = dbs; i; i = i->next) {
+		pmpkg_t *pkg = _alpm_db_get_pkgfromcache(i->data, dep->name);
+		if(pkg && alpm_depcmp(pkg, dep) && !_alpm_pkg_find(excluding, pkg->name)) {
+			if(_alpm_pkg_should_ignore(pkg)) {
+				int install;
+				QUESTION(handle->trans, PM_TRANS_CONV_INSTALL_IGNOREPKG, pkg,
+			                 tpkg, NULL, &install);
+				if(!install) {
+					continue;
 				}
 			}
+			return(pkg);
 		}
 	}
+	/* 2. satisfiers (skip literals here) */
+	for(i = dbs; i; i = i->next) {
+		for(j = _alpm_db_get_pkgcache(i->data); j; j = j->next) {
+			pmpkg_t *pkg = j->data;
+			if(alpm_depcmp(pkg, dep) && strcmp(pkg->name, dep->name) &&
+			             !_alpm_pkg_find(excluding, pkg->name)) {
+				if(_alpm_pkg_should_ignore(pkg)) {
+					int install;
+					QUESTION(handle->trans, PM_TRANS_CONV_INSTALL_IGNOREPKG, pkg,
+				                 tpkg, NULL, &install);
+					if(!install) {
+						continue;
+					}
+				}
+				return(pkg);
+			}
+		}
+	}
+	return(NULL);
 }
 
-/* populates *list with packages that need to be installed to satisfy all
- * dependencies (recursive) for syncpkg
+/* populates list with packages that need to be installed to satisfy all
+ * dependencies of packages in list
  *
  * @param remove contains packages elected for removal
- * make sure **list is already initialized
  */
-int _alpm_resolvedeps(pmdb_t *local, alpm_list_t *dbs_sync, pmpkg_t *syncpkg,
-                      alpm_list_t **list, alpm_list_t *remove, pmtrans_t *trans, alpm_list_t **data)
+int _alpm_resolvedeps(pmdb_t *local, alpm_list_t *dbs_sync, alpm_list_t *list,
+                      alpm_list_t *remove, alpm_list_t **data)
 {
-	alpm_list_t *i, *j, *k;
+	alpm_list_t *i, *j;
 	alpm_list_t *targ;
 	alpm_list_t *deps = NULL;
 
 	ALPM_LOG_FUNC;
 
-	if(local == NULL || dbs_sync == NULL || syncpkg == NULL || list == NULL) {
+	if(local == NULL || dbs_sync == NULL) {
 		return(-1);
 	}
 
 	_alpm_log(PM_LOG_DEBUG, "started resolving dependencies\n");
-	targ = alpm_list_add(NULL, syncpkg);
-	deps = alpm_checkdeps(local, 0, remove, targ);
-	alpm_list_free(targ);
-
-	if(deps == NULL) {
-		return(0);
-	}
-
-	for(i = deps; i; i = i->next) {
-		int found = 0;
-		pmdepmissing_t *miss = i->data;
-		pmdepend_t *missdep = &(miss->depend);
-		pmpkg_t *sync = NULL;
-
-		/* check if one of the packages in *list already satisfies this dependency */
-		for(j = *list; j && !found; j = j->next) {
-			pmpkg_t *sp = j->data;
-			if(alpm_depcmp(sp, missdep)) {
-				char *missdepstring = alpm_dep_get_string(missdep);
-				_alpm_log(PM_LOG_DEBUG, "%s satisfies dependency %s -- skipping\n",
-				          alpm_pkg_get_name(sp), missdepstring);
-				free(missdepstring);
-				found = 1;
-			}
-		}
-		if(found) {
-			continue;
-		}
-
-		/* find the package in one of the repositories */
-		/* check literals */
-		for(j = dbs_sync; j && !found; j = j->next) {
-			sync = _alpm_db_get_pkgfromcache(j->data, missdep->name);
-			if(!sync) {
+	for(i = list; i; i = i->next) {
+		pmpkg_t *tpkg = i->data;
+		targ = alpm_list_add(NULL, tpkg);
+		deps = alpm_checkdeps(local, 0, remove, targ);
+		alpm_list_free(targ);
+		for(j = deps; j; j = j->next) {
+			pmdepmissing_t *miss = j->data;
+			pmdepend_t *missdep = alpm_miss_get_dep(miss);
+			/* check if one of the packages in list already satisfies this dependency */
+			if(_alpm_find_dep_satisfier(list, missdep)) {
 				continue;
 			}
-			found = alpm_depcmp(sync, missdep) && !_alpm_pkg_find(alpm_pkg_get_name(sync), remove);
-			if(!found) {
-				continue;
-			}
-			/* If package is in the ignorepkg list, ask before we pull it */
-			if(_alpm_pkg_should_ignore(sync)) {
-				pmpkg_t *dummypkg = _alpm_pkg_new(miss->target, NULL);
-				QUESTION(trans, PM_TRANS_CONV_INSTALL_IGNOREPKG, dummypkg, sync, NULL, &found);
-				_alpm_pkg_free(dummypkg);
-			}
-		}
-		/*TODO this autoresolves the first 'satisfier' package... we should fix this
-		 * somehow */
-		/* check provides */
-		/* we don't check literals again to avoid duplicated PM_TRANS_CONV_INSTALL_IGNOREPKG messages */
-		for(j = dbs_sync; j && !found; j = j->next) {
-			for(k = _alpm_db_get_pkgcache(j->data); k && !found; k = k->next) {
-				sync = k->data;
-				if(!sync) {
-					continue;
-				}
-				found = alpm_depcmp(sync, missdep) && strcmp(sync->name, missdep->name)
-					&& !_alpm_pkg_find(alpm_pkg_get_name(sync), remove);
-				if(!found) {
-					continue;
-				}
-				if(_alpm_pkg_should_ignore(sync)) {
-					pmpkg_t *dummypkg = _alpm_pkg_new(miss->target, NULL);
-					QUESTION(trans, PM_TRANS_CONV_INSTALL_IGNOREPKG, dummypkg, sync, NULL, &found);
-					_alpm_pkg_free(dummypkg);
+			/* find a satisfier package in the given repositories */
+			pmpkg_t *spkg = _alpm_resolvedep(missdep, dbs_sync, list, tpkg);
+			if(!spkg) {
+				pm_errno = PM_ERR_UNSATISFIED_DEPS;
+				char *missdepstring = alpm_dep_get_string(missdep);
+				_alpm_log(PM_LOG_ERROR, _("cannot resolve \"%s\", a dependency of \"%s\"\n"),
+			                               missdepstring, tpkg->name);
+				free(missdepstring);
+				if(data) {
+					pmdepmissing_t *missd = _alpm_depmiss_new(miss->target,
+					                           miss->depend, miss->causingpkg);
+					if(missd) {
+						*data = alpm_list_add(*data, missd);
+					}
 				}
+				alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_depmiss_free);
+				alpm_list_free(deps);
+				return(-1);
+			}  else {
+				_alpm_log(PM_LOG_DEBUG, "pulling dependency %s (needed by %s)\n",
+					  alpm_pkg_get_name(spkg), alpm_pkg_get_name(tpkg));
+				list = alpm_list_add(list, spkg);
 			}
 		}
+		alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_depmiss_free);
+		alpm_list_free(deps);
+	}
+	_alpm_log(PM_LOG_DEBUG, "finished resolving dependencies\n");
+	return(0);
+}
 
-		if(!found) {
-			char *missdepstring = alpm_dep_get_string(missdep);
-			_alpm_log(PM_LOG_ERROR, _("cannot resolve \"%s\", a dependency of \"%s\"\n"),
-			          missdepstring, miss->target);
-			free(missdepstring);
-			if(data) {
-				MALLOC(miss, sizeof(pmdepmissing_t),/*nothing*/);
-				if(!miss) {
-					pm_errno = PM_ERR_MEMORY;
-					FREELIST(*data);
-					goto error;
-				}
-				*miss = *(pmdepmissing_t *)i->data;
-				*data = alpm_list_add(*data, miss);
-			}
-			pm_errno = PM_ERR_UNSATISFIED_DEPS;
-			goto error;
-		} else {
-			_alpm_log(PM_LOG_DEBUG, "pulling dependency %s (needed by %s)\n",
-					alpm_pkg_get_name(sync), alpm_pkg_get_name(syncpkg));
-			*list = alpm_list_add(*list, sync);
-			if(_alpm_resolvedeps(local, dbs_sync, sync, list, remove, trans, data)) {
-				goto error;
-			}
+/* Does pkg1 depend on pkg2, ie. does pkg2 satisfy a dependency of pkg1? */
+int _alpm_dep_edge(pmpkg_t *pkg1, pmpkg_t *pkg2)
+{
+	alpm_list_t *i;
+	for(i = alpm_pkg_get_depends(pkg1); i; i = i->next) {
+		if(alpm_depcmp(pkg2, i->data)) {
+			return(1);
 		}
 	}
+	return(0);
+}
 
-	_alpm_log(PM_LOG_DEBUG, "finished resolving dependencies\n");
-
-	FREELIST(deps);
+const char SYMEXPORT *alpm_miss_get_target(const pmdepmissing_t *miss)
+{
+	ALPM_LOG_FUNC;
 
-	return(0);
+	/* Sanity checks */
+	ASSERT(miss != NULL, return(NULL));
 
-error:
-	FREELIST(deps);
-	return(-1);
+	return(miss->target);
 }
 
-const char SYMEXPORT *alpm_miss_get_target(const pmdepmissing_t *miss)
+const char SYMEXPORT *alpm_miss_get_causingpkg(const pmdepmissing_t *miss)
 {
 	ALPM_LOG_FUNC;
 
 	/* Sanity checks */
 	ASSERT(miss != NULL, return(NULL));
 
-	return miss->target;
+	return miss->causingpkg;
 }
 
 pmdepend_t SYMEXPORT *alpm_miss_get_dep(pmdepmissing_t *miss)
@@ -637,7 +675,7 @@ pmdepend_t SYMEXPORT *alpm_miss_get_dep(pmdepmissing_t *miss)
 	/* Sanity checks */
 	ASSERT(miss != NULL, return(NULL));
 
-	return &(miss->depend);
+	return(miss->depend);
 }
 
 pmdepmod_t SYMEXPORT alpm_dep_get_mod(const pmdepend_t *dep)
@@ -647,7 +685,7 @@ pmdepmod_t SYMEXPORT alpm_dep_get_mod(const pmdepend_t *dep)
 	/* Sanity checks */
 	ASSERT(dep != NULL, return(-1));
 
-	return dep->mod;
+	return(dep->mod);
 }
 
 const char SYMEXPORT *alpm_dep_get_name(const pmdepend_t *dep)
@@ -657,7 +695,7 @@ const char SYMEXPORT *alpm_dep_get_name(const pmdepend_t *dep)
 	/* Sanity checks */
 	ASSERT(dep != NULL, return(NULL));
 
-	return dep->name;
+	return(dep->name);
 }
 
 const char SYMEXPORT *alpm_dep_get_version(const pmdepend_t *dep)
@@ -667,7 +705,7 @@ const char SYMEXPORT *alpm_dep_get_version(const pmdepend_t *dep)
 	/* Sanity checks */
 	ASSERT(dep != NULL, return(NULL));
 
-	return dep->version;
+	return(dep->version);
 }
 
 /** Reverse of splitdep; make a dep string from a pmdepend_t struct.
@@ -677,7 +715,7 @@ const char SYMEXPORT *alpm_dep_get_version(const pmdepend_t *dep)
  */
 char SYMEXPORT *alpm_dep_get_string(const pmdepend_t *dep)
 {
-	char *opr, *str = NULL;
+	char *name, *opr, *ver, *str = NULL;
 	size_t len;
 
 	ALPM_LOG_FUNC;
@@ -685,6 +723,12 @@ char SYMEXPORT *alpm_dep_get_string(const pmdepend_t *dep)
 	/* Sanity checks */
 	ASSERT(dep != NULL, return(NULL));
 
+	if(dep->name) {
+		name = dep->name;
+	} else {
+		name = "";
+	}
+
 	switch(dep->mod) {
 		case PM_DEP_MOD_ANY:
 			opr = "";
@@ -709,11 +753,18 @@ char SYMEXPORT *alpm_dep_get_string(const pmdepend_t *dep)
 			break;
 	}
 
+	if(dep->version) {
+		ver = dep->version;
+	} else {
+		ver = "";
+	}
+
 	/* we can always compute len and print the string like this because opr
-	 * and ver will be empty when PM_DEP_MOD_ANY is the depend type */
-	len = strlen(dep->name) + strlen(opr) + strlen(dep->version) + 1;
+	 * and ver will be empty when PM_DEP_MOD_ANY is the depend type. the
+	 * reassignments above also ensure we do not do a strlen(NULL). */
+	len = strlen(name) + strlen(opr) + strlen(ver) + 1;
 	MALLOC(str, len, RET_ERR(PM_ERR_MEMORY, NULL));
-	snprintf(str, len, "%s%s%s", dep->name, opr, dep->version);
+	snprintf(str, len, "%s%s%s", name, opr, ver);
 
 	return(str);
 }