Avoid unnecessary string copies

Do not duplicate the strings for enumeration keys, as they are read-
only.

src/commons.c

@@ -196,13 +196,13 @@ str2enum (const GEnum map[], int len, const char *str) {
  *
  * On error, -1 is returned.
  * On success, the enumerated module value is returned. */
-char *
+const char *
 enum2str (const GEnum map[], int len, int idx) {
   int i;
 
   for (i = 0; i < len; ++i) {
     if (idx == map[i].idx)
-      return xstrdup (map[i].str);
+      return map[i].str;
   }
 
   return NULL;
@@ -221,7 +221,7 @@ get_module_enum (const char *str) {
  *
  * On error, NULL is returned.
  * On success, the string module value is returned. */
-char *
+const char *
 get_module_str (GModule module) {
   return enum2str (enum_modules, ARRAY_SIZE (enum_modules), module);
 }

src/commons.h

@@ -262,8 +262,8 @@ extern int module_list[TOTAL_MODULES];
 GAgents *new_gagents (uint32_t size);
 void free_agents_array (GAgents *agents);
 
-char *enum2str (const GEnum map[], int len, int idx);
-char *get_module_str (GModule module);
+const char *enum2str (const GEnum map[], int len, int idx);
+const char *get_module_str (GModule module);
 float get_percentage (unsigned long long total, unsigned long long hit);
 int get_max_choices (void);
 int get_module_enum (const char *str);

src/gkhash.c

@@ -71,7 +71,7 @@ new_gkdb (void) {
  *
  * On error, NULL is returned.
  * On success, the string module value is returned. */
-char *
+const char *
 get_mtr_type_str (GSMetricType type) {
   static const GEnum enum_metric_types[] = {
     {"II32", MTRC_TYPE_II32},

src/gkhash.h

@@ -185,7 +185,7 @@ uint32_t *get_sorted_dates (uint32_t * len);
 void free_storage (void);
 void init_pre_storage (Logs *logs);
 
-char *get_mtr_type_str (GSMetricType type);
+const char *get_mtr_type_str (GSMetricType type);
 void *get_db_instance (uint32_t key);
 void *get_hdb (GKDB * db, GAMetric mtrc);
 

src/gkmhash.c

@@ -420,7 +420,7 @@ ht_insert_keymap (GModule module, uint32_t date, uint32_t key, uint32_t *ckey) {
   khash_t (ii32) * cache = get_hash_from_cache (module, MTRC_KEYMAP);
 
   uint32_t val = 0;
-  char *modstr = NULL;
+  const char *modstr;
 
   if (!hash)
     return 0;
@@ -432,11 +432,9 @@ ht_insert_keymap (GModule module, uint32_t date, uint32_t key, uint32_t *ckey) {
 
   modstr = get_module_str (module);
   if ((val = ins_ii32_inc (hash, key, ht_ins_seq, seqs, modstr)) == 0) {
-    free (modstr);
     return val;
   }
   *ckey = ins_ii32_ai (cache, key);
-  free (modstr);
 
   return val;
 }

src/gstorage.c

@@ -445,7 +445,7 @@ free_gmetrics (GMetrics *metric) {
  *
  * On error, NULL is returned.
  * On success, the string module value is returned. */
-char *
+const char *
 get_mtr_str (GSMetric metric) {
   /* String modules to enumerated modules */
   static const GEnum enum_metrics[] = {

src/gstorage.h

@@ -143,7 +143,7 @@ extern const httpprotocols http_protocols[];
 extern const size_t http_methods_len;
 extern const size_t http_protocols_len;
 
-char *get_mtr_str (GSMetric metric);
+const char *get_mtr_str (GSMetric metric);
 int excluded_ip (GLogItem * logitem);
 uint32_t *i322ptr (uint32_t val);
 uint64_t *uint642ptr (uint64_t val);

src/persistence.c

@@ -232,7 +232,8 @@ build_filename (const char *type, const char *modstr, const char *mtrstr) {
  * On success, the filename is returned */
 static char *
 get_filename (GModule module, GKHashMetric mtrc) {
-  char *mtrstr = NULL, *modstr = NULL, *type = NULL, *fn = NULL;
+  const char *mtrstr, *modstr, *type;
+  char *fn = NULL;
 
   if (!(mtrstr = get_mtr_str (mtrc.metric.storem)))
     FATAL ("Unable to allocate metric name.");
@@ -243,10 +244,6 @@ get_filename (GModule module, GKHashMetric mtrc) {
 
   fn = build_filename (type, modstr, mtrstr);
 
-  free (mtrstr);
-  free (type);
-  free (modstr);
-
   return fn;
 }
 
@@ -945,7 +942,7 @@ migrate_metric (GModule module, GKHashMetric mtrc) {
 
   int ret = 0;
   char *fn = NULL, *path = NULL;
-  char *modstr = NULL, *mtrstr = NULL;
+  const char *modstr, *mtrstr;
   khint_t k;
 
   k = kh_get (si32, db_props, "version");
@@ -1001,8 +998,6 @@ migrate_metric (GModule module, GKHashMetric mtrc) {
   }
 
   free (fn);
-  free (modstr);
-  free (mtrstr);
   free (path);
 
   return ret;