qemuInteropFetchConfigs: Don't use 'virStringListAdd' to construct list

'virHashGetItems' already returns the number of entries which will be
considered for addition to the list so we can allocate it to the upper
bound upfront rather than growing it in a loop. This avoids the
quadratic complexity of 'virStringListAdd'.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

diff --git a/src/qemu/qemu_interop_config.c b/src/qemu/qemu_interop_config.c
index bcaddda446a8328f6d3cdb2fe36d838736f1a7af..9733df7194a77c62902080a8b532e17b18f5d6d4 100644 (file)
--- a/src/qemu/qemu_interop_config.c
+++ b/src/qemu/qemu_interop_config.c
@@ -94,7 +94,9 @@ qemuInteropFetchConfigs(const char *name,
     g_autofree char *sysLocation = virFileBuildPath(QEMU_SYSTEM_LOCATION, name, NULL);
     g_autofree char *etcLocation = virFileBuildPath(QEMU_ETC_LOCATION, name, NULL);
     g_autofree virHashKeyValuePairPtr pairs = NULL;
+    size_t npairs;
     virHashKeyValuePairPtr tmp = NULL;
+    size_t nconfigs = 0;
 
     *configs = NULL;
 
@@ -132,11 +134,13 @@ qemuInteropFetchConfigs(const char *name,
      * where each filename (as key) has the highest priority full pathname
      * associated with it. */
 
-    if (virHashSize(files) == 0)
+    if (!(pairs = virHashGetItems(files, &npairs, true)))
+        return -1;
+
+    if (npairs == 0)
         return 0;
 
-    if (!(pairs = virHashGetItems(files, NULL, true)))
-        return -1;
+    *configs = g_new0(char *, npairs + 1);
 
     for (tmp = pairs; tmp->key; tmp++) {
         const char *path = tmp->value;
@@ -158,8 +162,7 @@ qemuInteropFetchConfigs(const char *name,
             continue;
         }
 
-        if (virStringListAdd(configs, path) < 0)
-            return -1;
+        (*configs)[nconfigs++] = g_strdup(path);
     }
 
     return 0;