[pacman-dev] [PATCH] New _alpm_find_first_satisfier function.

[Xavier Chantry]

Address two concerns brought up by Nagy about the _alpm_find_dep_satisfier
function by adding the following new function :
pmpkg_t *_alpm_find_first_satisfier(alpm_list_t *pkgs, pmdepend_t *dep)

This function just returns the first satisfier, so this takes care of the
performance problem by restoring the old behavior. The memleak was also
fixed.

Ref: http://www.archlinux.org/pipermail/pacman-dev/2008-May/011779.html

Signed-off-by: Xavier Chantry <shiningxc at gmail.com>
---
 lib/libalpm/deps.c |   37 ++++++++++++++++++++++++++++++-------
 lib/libalpm/deps.h |    1 +
 2 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/lib/libalpm/deps.c b/lib/libalpm/deps.c
index 37e9916..383f02d 100644
--- a/lib/libalpm/deps.c
+++ b/lib/libalpm/deps.c
@@ -194,7 +194,10 @@ alpm_list_t *_alpm_sortbydeps(alpm_list_t *targets, int reverse)
 	return(newtargs);
 }
 
-alpm_list_t *_alpm_find_dep_satisfiers(alpm_list_t *pkgs, pmdepend_t *dep)
+/* if full > 0, return the full list of satisfiers
+ * if full == 0, return the first satisfier
+ */
+static alpm_list_t *find_dep_satisfiers(alpm_list_t *pkgs, pmdepend_t *dep, int full)
 {
 	alpm_list_t *i, *ret = NULL;
 
@@ -202,11 +205,31 @@ alpm_list_t *_alpm_find_dep_satisfiers(alpm_list_t *pkgs, pmdepend_t *dep)
 		pmpkg_t *pkg = i->data;
 		if(alpm_depcmp(pkg, dep)) {
 			ret = alpm_list_add(ret, pkg);
+			if(!full) {
+				break;
+			}
 		}
 	}
 	return(ret);
 }
 
+alpm_list_t *_alpm_find_dep_satisfiers(alpm_list_t *pkgs, pmdepend_t *dep)
+{
+	return(find_dep_satisfiers(pkgs, dep, 1));
+}
+
+pmpkg_t *_alpm_find_first_satisfier(alpm_list_t *pkgs, pmdepend_t *dep)
+{
+	pmpkg_t *pkg = NULL;
+	alpm_list_t *list = find_dep_satisfiers(pkgs, dep, 0);
+	if(list) {
+		pkg = list->data;
+		alpm_list_free(list);
+	}
+	return(pkg);
+}
+
+
 /** 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
@@ -237,7 +260,7 @@ alpm_list_t SYMEXPORT *alpm_deptest(pmdb_t *db, alpm_list_t *targets)
 		target = alpm_list_getdata(i);
 		dep = _alpm_splitdep(target);
 
-		if(!_alpm_find_dep_satisfiers(_alpm_db_get_pkgcache(db), dep)) {
+		if(!_alpm_find_first_satisfier(_alpm_db_get_pkgcache(db), dep)) {
 			ret = alpm_list_add(ret, target);
 		}
 		_alpm_dep_free(dep);
@@ -288,8 +311,8 @@ 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_find_dep_satisfiers(upgrade, depend) &&
-			   !_alpm_find_dep_satisfiers(dblist, depend)) {
+			if(!_alpm_find_first_satisfier(upgrade, depend) &&
+			   !_alpm_find_first_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",
@@ -308,13 +331,13 @@ 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_list_getdata(_alpm_find_dep_satisfiers(modified, depend));
+				pmpkg_t *causingpkg = _alpm_find_first_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(causingpkg &&
-				   !_alpm_find_dep_satisfiers(upgrade, depend) &&
-				   !_alpm_find_dep_satisfiers(dblist, depend)) {
+				   !_alpm_find_first_satisfier(upgrade, depend) &&
+				   !_alpm_find_first_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));
diff --git a/lib/libalpm/deps.h b/lib/libalpm/deps.h
index 70badfd..5c7da87 100644
--- a/lib/libalpm/deps.h
+++ b/lib/libalpm/deps.h
@@ -52,6 +52,7 @@ int _alpm_resolvedeps(pmdb_t *local, alpm_list_t *dbs_sync, pmpkg_t *syncpkg,
 		**data);
 pmdepend_t *_alpm_splitdep(const char *depstring);
 alpm_list_t *_alpm_find_dep_satisfiers(alpm_list_t *pkgs, pmdepend_t *dep);
+pmpkg_t *_alpm_find_first_satisfier(alpm_list_t *pkgs, pmdepend_t *dep);
 
 #endif /* _ALPM_DEPS_H */
 
-- 
1.5.5.1