[syslog-ng] [PATCH (3.4) 1/1] value-pairs: Use a GPtrArray for explicit name=value pairs

[Gergely Nagy]

Instead of storing the name-value pairs explicitly set by the user in
a GHashTable, store them in a GPtrArray. This has the advantage of
being both lighter and faster to both insert and traverse, at the cost
of making collissions more costy.

If there are two entries with the same key, the templates of both will
be evaluated, but only the latter will be used, which is a minor
performance hit. But not using GHashTable outweights that.

Signed-off-by: Gergely Nagy <algernon at balabit.hu>
---
 lib/value-pairs.c |   44 ++++++++++++++++++++++++++++++++------------
 1 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/lib/value-pairs.c b/lib/value-pairs.c
index 671d4f4..86649dd 100644
--- a/lib/value-pairs.c
+++ b/lib/value-pairs.c
@@ -39,10 +39,16 @@ typedef struct
   gboolean include;
 } VPPatternSpec;
 
+typedef struct
+{
+  gchar *name;
+  gchar *template;
+} VPPairConf;
+
 struct _ValuePairs
 {
   VPPatternSpec **patterns;
-  GHashTable *vpairs;
+  GPtrArray *vpairs;
   GList *transforms;
 
   /* guint32 as CfgFlagHandler only supports 32 bit integers */
@@ -148,11 +154,13 @@ value_pairs_add_glob_pattern(ValuePairs *vp, const gchar *pattern,
 void
 value_pairs_add_pair(ValuePairs *vp, GlobalConfig *cfg, const gchar *key, const gchar *value)
 {
-  LogTemplate *t = NULL;
+  VPPairConf *p = g_new(VPPairConf, 1);
+
+  p->name = g_strdup(key);
+  p->template = log_template_new(cfg, NULL);
+  log_template_compile(p->template, value, NULL);
 
-  t = log_template_new(cfg, NULL);
-  log_template_compile(t, value, NULL);
-  g_hash_table_insert(vp->vpairs, g_strdup(key), t);
+  g_ptr_array_add(vp->vpairs, p);
 }
 
 static gchar *
@@ -179,15 +187,16 @@ vp_transform_apply (ValuePairs *vp, gchar *key)
 
 /* runs over the name-value pairs requested by the user (e.g. with value_pairs_add_pair) */
 static void
-vp_pairs_foreach(gpointer key, gpointer value, gpointer user_data)
+vp_pairs_foreach(gpointer data, gpointer user_data)
 {
   ValuePairs *vp = ((gpointer *)user_data)[0];
   LogMessage *msg = ((gpointer *)user_data)[2];
   gint32 seq_num = GPOINTER_TO_INT (((gpointer *)user_data)[3]);
   GTree *scope_set = ((gpointer *)user_data)[5];
   ScratchBuffer *sb = scratch_buffer_acquire();
+  VPPairConf *vpc = (VPPairConf *)data;
 
-  log_template_format((LogTemplate *)value, msg, NULL, LTZ_LOCAL,
+  log_template_format((LogTemplate *)vpc->template, msg, NULL, LTZ_LOCAL,
                       seq_num, NULL, sb_string(sb));
 
   if (!sb_string(sb)->str[0])
@@ -196,7 +205,8 @@ vp_pairs_foreach(gpointer key, gpointer value, gpointer user_data)
       return;
     }
 
-  g_tree_insert(scope_set, vp_transform_apply(vp, key), sb_string(sb)->str);
+  g_tree_insert(scope_set, vp_transform_apply(vp, vpc->name),
+                sb_string(sb)->str);
   g_string_steal(sb_string(sb));
   scratch_buffer_release(sb);
 }
@@ -313,7 +323,7 @@ value_pairs_foreach_sorted (ValuePairs *vp, VPForeachFunc func,
     vp_merge_set(vp, msg, seq_num, all_macros, scope_set);
 
   /* Merge the explicit key-value pairs too */
-  g_hash_table_foreach(vp->vpairs, (GHFunc) vp_pairs_foreach, args);
+  g_ptr_array_foreach(vp->vpairs, (GFunc)vp_pairs_foreach, args);
 
   /* Aaand we run it through the callback! */
   g_tree_foreach(scope_set, (GTraverseFunc)func, user_data);
@@ -355,6 +365,16 @@ value_pairs_init_set(ValuePairSpec *set)
     }
 }
 
+static void
+vp_free_pair(gpointer data)
+{
+  VPPairConf *vpc = (VPPairConf *)data;
+
+  log_template_unref(vpc->template);
+  g_free(vpc->name);
+  g_free(vpc);
+}
+
 ValuePairs *
 value_pairs_new(void)
 {
@@ -363,8 +383,8 @@ value_pairs_new(void)
   GArray *a;
 
   vp = g_new0(ValuePairs, 1);
-  vp->vpairs = g_hash_table_new_full(g_str_hash, g_str_equal, g_free,
-				     (GDestroyNotify) log_template_unref);
+  vp->vpairs = g_ptr_array_sized_new(8);
+  g_ptr_array_set_free_func(vp->vpairs, vp_free_pair);
 
   if (!value_pair_sets_initialized)
     {
@@ -403,7 +423,7 @@ value_pairs_free (ValuePairs *vp)
   gint i;
   GList *l;
 
-  g_hash_table_destroy(vp->vpairs);
+  g_ptr_array_free(vp->vpairs, TRUE);
 
   for (i = 0; i < vp->patterns_size; i++)
     {
-- 
1.7.9