[libgda] GdaMetaStore: avoid static variable for attributes

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 806a0b3c2099ebd1eed71a33c7a156f0f364fd25
Author: Daniel Espinosa <esodan gmail com>
Date:   Fri Aug 2 11:56:05 2019 -0500

    GdaMetaStore: avoid static variable for attributes
    
    static variables are potential memory leaks and are
    hard to coordinate on mutil-threaded environments

 libgda/gda-meta-store.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)
---
diff --git a/libgda/gda-meta-store.c b/libgda/gda-meta-store.c
index d0ecb49e0..86aa0451e 100644
--- a/libgda/gda-meta-store.c
+++ b/libgda/gda-meta-store.c
@@ -657,6 +657,7 @@ typedef struct {
                                              * the parameters separated by a period,
                                              * value = a TableConditionInfo structure */
        GHashTable    *provider_specifics; /* key = a ProviderSpecificKey , value = a ProviderSpecificValue */
+  GdaSet        *attributes_set;
 } GdaMetaStorePrivate;
 
 
@@ -899,7 +900,7 @@ gda_meta_store_init (GdaMetaStore *store)
        priv->prep_stmts[STMT_DEL_DECLARE_FK] =
                compute_prepared_stmt (priv->parser,
                                       "DELETE FROM __declared_fk WHERE constraint_name = ##fkname::string 
AND table_catalog = ##tcal::string AND table_schema = ##tschema::string AND table_name = ##tname::string AND 
ref_table_catalog = ##ref_tcal::string AND ref_table_schema = ##ref_tschema::string AND ref_table_name = 
##ref_tname::string");
-
+  priv->attributes_set = NULL;
 /*#define GDA_DEBUG_GRAPH*/
 #ifdef GDA_DEBUG_GRAPH
 #define INFORMATION_SCHEMA_GRAPH_FILE "information_schema.dot"
@@ -1154,6 +1155,10 @@ gda_meta_store_dispose (GObject *object)
     g_free (priv->prep_stmts);
     priv->prep_stmts = NULL;
   }
+  if (priv->attributes_set != NULL) {
+    g_object_unref (priv->attributes_set);
+    priv->attributes_set = NULL;
+  }
 
        g_rec_mutex_clear (& (priv->mutex));
 
@@ -4371,8 +4376,6 @@ gboolean
 gda_meta_store_set_attribute_value (GdaMetaStore *store, const gchar *att_name,
                                    const gchar *att_value, GError **error)
 {
-       static GMutex set_mutex;
-       static GdaSet *set = NULL;
        gboolean started_transaction = FALSE;
 
        g_return_val_if_fail (GDA_IS_META_STORE (store), FALSE);
@@ -4387,17 +4390,14 @@ gda_meta_store_set_attribute_value (GdaMetaStore *store, const gchar *att_name,
 
        g_rec_mutex_lock (& (priv->mutex));
 
-       g_mutex_lock (&set_mutex);
-       if (!set) {
-               if (!gda_statement_get_parameters (priv->prep_stmts [STMT_SET_ATT_VALUE], &set, error)) {
-                       g_mutex_unlock (&set_mutex);
+       if (!priv->attributes_set) {
+               if (!gda_statement_get_parameters (priv->prep_stmts [STMT_SET_ATT_VALUE], 
&priv->attributes_set, error)) {
                        g_rec_mutex_unlock (& (priv->mutex));
                        return FALSE;
                }
        }
-       g_mutex_unlock (&set_mutex);
 
-       if (!gda_set_set_holder_value (set, error, "name", att_name)) {
+       if (!gda_set_set_holder_value (priv->attributes_set, error, "name", att_name)) {
                g_rec_mutex_unlock (& (priv->mutex));
                return FALSE;
        }
@@ -4415,17 +4415,17 @@ gda_meta_store_set_attribute_value (GdaMetaStore *store, const gchar *att_name,
 
        /* delete existing attribute */
        if (gda_connection_statement_execute_non_select (priv->cnc,
-                                                        priv->prep_stmts [STMT_DEL_ATT_VALUE], set,
+                                                        priv->prep_stmts [STMT_DEL_ATT_VALUE], 
priv->attributes_set,
                                                         NULL, error) == -1)
                goto onerror;
 
        if (att_value) {
                /* set new attribute */
-               if (!gda_set_set_holder_value (set, error, "value", att_value))
+               if (!gda_set_set_holder_value (priv->attributes_set, error, "value", att_value))
                        goto onerror;
 
                if (gda_connection_statement_execute_non_select (priv->cnc,
-                                                                priv->prep_stmts [STMT_SET_ATT_VALUE], set,
+                                                                priv->prep_stmts [STMT_SET_ATT_VALUE], 
priv->attributes_set,
                                                                 NULL, error) == -1)
                        goto onerror;
        }
@@ -5455,3 +5455,4 @@ gda_meta_store_create_struct (GdaMetaStore *store, GdaMetaStructFeature features
 {
   return (GdaMetaStruct*) g_object_new (GDA_TYPE_META_STRUCT, "meta-store", store, "features", features, 
NULL);
 }
+