[libgda] GdaPostgresProvider: avoid static statements

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit ec98d8394399c32ba5d55aa450e9d40a2341ad66
Author: Daniel Espinosa <esodan gmail com>
Date:   Fri Aug 2 11:52:53 2019 -0500

    GdaPostgresProvider: avoid static statements
    
    static variables are potential memory leaks and
    can push problems on multi-thread environments

 providers/postgres/gda-postgres-provider.c | 80 +++++++++++++++++++-----------
 1 file changed, 51 insertions(+), 29 deletions(-)
---
diff --git a/providers/postgres/gda-postgres-provider.c b/providers/postgres/gda-postgres-provider.c
index e325f6763..77936c035 100644
--- a/providers/postgres/gda-postgres-provider.c
+++ b/providers/postgres/gda-postgres-provider.c
@@ -62,8 +62,19 @@
  */
 static void gda_postgres_provider_class_init (GdaPostgresProviderClass *klass);
 static void gda_postgres_provider_init       (GdaPostgresProvider *provider);
+static void gda_postgres_provider_dispose (GObject *object);
 
-G_DEFINE_TYPE (GdaPostgresProvider, gda_postgres_provider, GDA_TYPE_SERVER_PROVIDER)
+
+typedef struct {
+  /*
+   * Prepared internal statements
+   * TO_ADD: any prepared statement to be used internally by the provider should be
+   *         declared here, as constants and as SQL statements
+   */
+  GdaStatement **internal_stmt;
+} GdaPostgresProviderPrivate;
+
+G_DEFINE_TYPE_WITH_PRIVATE (GdaPostgresProvider, gda_postgres_provider, GDA_TYPE_SERVER_PROVIDER)
 
 /*
  * GdaServerProvider's virtual methods
@@ -163,14 +174,6 @@ static GList   *gda_postgres_provider_xa_recover  (GdaServerProvider *provider,
  */
 static void gda_postgres_free_cnc_data (PostgresConnectionData *cdata);
 
-
-/*
- * Prepared internal statements
- * TO_ADD: any prepared statement to be used internally by the provider should be
- *         declared here, as constants and as SQL statements
- */
-static GdaStatement **internal_stmt = NULL;
-
 typedef enum {
        I_STMT_BEGIN,
        I_STMT_COMMIT,
@@ -257,28 +260,39 @@ gda_postgres_provider_class_init (GdaPostgresProviderClass *klass)
        gda_server_provider_set_impl_functions (provider_class,
                                                GDA_SERVER_PROVIDER_FUNCTIONS_XA,
                                                (gpointer) &postgres_xa_functions);
+  G_OBJECT_CLASS (provider_class)->dispose = gda_postgres_provider_dispose;
 }
 
 static void
 gda_postgres_provider_init (GdaPostgresProvider *postgres_prv)
 {
-       if (!internal_stmt) {
-               InternalStatementItem i;
-               GdaSqlParser *parser;
+       GdaPostgresProviderPrivate *priv = gda_postgres_provider_get_instance_private (postgres_prv);
+       InternalStatementItem i;
+       GdaSqlParser *parser;
 
-               parser = gda_server_provider_internal_get_parser ((GdaServerProvider*) postgres_prv);
-               internal_stmt = g_new0 (GdaStatement *, sizeof (internal_sql) / sizeof (gchar*));
-               for (i = I_STMT_BEGIN; i < sizeof (internal_sql) / sizeof (gchar*); i++) {
-                       internal_stmt[i] = gda_sql_parser_parse_string (parser, internal_sql[i], NULL, NULL);
-                       if (!internal_stmt[i])
-                               g_error ("Could not parse internal statement: %s\n", internal_sql[i]);
-               }
+       parser = gda_server_provider_internal_get_parser ((GdaServerProvider*) postgres_prv);
+       priv->internal_stmt = g_new0 (GdaStatement *, sizeof (internal_sql) / sizeof (gchar*));
+       for (i = I_STMT_BEGIN; i < sizeof (internal_sql) / sizeof (gchar*); i++) {
+               priv->internal_stmt[i] = gda_sql_parser_parse_string (parser, internal_sql[i], NULL, NULL);
+               if (!priv->internal_stmt[i])
+                       g_error ("Could not parse internal statement: %s\n", internal_sql[i]);
        }
 
        /* meta data init */
        _gda_postgres_provider_meta_init ((GdaServerProvider*) postgres_prv);
 }
 
+
+static void gda_postgres_provider_dispose (GObject *object) {
+  GdaPostgresProviderPrivate *priv = gda_postgres_provider_get_instance_private (GDA_POSTGRES_PROVIDER 
(object));
+  if (priv->internal_stmt != NULL) {
+    for (gulong i = I_STMT_BEGIN; i < sizeof (internal_sql) / sizeof (gchar*); i++) {
+                 g_object_unref (priv->internal_stmt[i]);
+         }
+    priv->internal_stmt = NULL;
+  }
+}
+
 static GdaWorker *
 gda_postgres_provider_create_worker (GdaServerProvider *provider, gboolean for_cnc)
 {
@@ -1049,6 +1063,8 @@ gda_postgres_provider_begin_transaction (GdaServerProvider *provider, GdaConnect
        g_return_val_if_fail (GDA_IS_CONNECTION (cnc), FALSE);
        g_return_val_if_fail (gda_connection_get_provider (cnc) == provider, FALSE);
 
+  GdaPostgresProviderPrivate *priv = gda_postgres_provider_get_instance_private (GDA_POSTGRES_PROVIDER 
(provider));
+
        cdata = (PostgresConnectionData*) gda_connection_internal_get_provider_data_error (cnc, error);
        if (!cdata)
                return FALSE;
@@ -1106,7 +1122,7 @@ gda_postgres_provider_begin_transaction (GdaServerProvider *provider, GdaConnect
        }
 
        /* BEGIN statement */
-       if (gda_connection_statement_execute_non_select (cnc, internal_stmt [I_STMT_BEGIN], NULL, NULL, 
error) == -1)
+       if (gda_connection_statement_execute_non_select (cnc, priv->internal_stmt [I_STMT_BEGIN], NULL, NULL, 
error) == -1)
                return FALSE;
 
        if (stmt) {
@@ -1129,6 +1145,7 @@ gda_postgres_provider_commit_transaction (GdaServerProvider *provider, GdaConnec
                                          G_GNUC_UNUSED const gchar *name, GError **error)
 {
        PostgresConnectionData *cdata;
+  GdaPostgresProviderPrivate *priv = gda_postgres_provider_get_instance_private (GDA_POSTGRES_PROVIDER 
(provider));
 
        g_return_val_if_fail (GDA_IS_CONNECTION (cnc), FALSE);
        g_return_val_if_fail (gda_connection_get_provider (cnc) == provider, FALSE);
@@ -1138,7 +1155,7 @@ gda_postgres_provider_commit_transaction (GdaServerProvider *provider, GdaConnec
                return FALSE;
 
        /* COMMIT statement */
-       if (gda_connection_statement_execute_non_select (cnc, internal_stmt [I_STMT_COMMIT], NULL, NULL, 
error) == -1)
+       if (gda_connection_statement_execute_non_select (cnc, priv->internal_stmt [I_STMT_COMMIT], NULL, 
NULL, error) == -1)
                return FALSE;
 
        return TRUE;
@@ -1153,6 +1170,7 @@ gda_postgres_provider_rollback_transaction (GdaServerProvider *provider,
                                            G_GNUC_UNUSED const gchar *name, GError **error)
 {
        PostgresConnectionData *cdata;
+  GdaPostgresProviderPrivate *priv = gda_postgres_provider_get_instance_private (GDA_POSTGRES_PROVIDER 
(provider));
 
        g_return_val_if_fail (GDA_IS_CONNECTION (cnc), FALSE);
        g_return_val_if_fail (gda_connection_get_provider (cnc) == provider, FALSE);
@@ -1162,7 +1180,7 @@ gda_postgres_provider_rollback_transaction (GdaServerProvider *provider,
                return FALSE;
 
        /* ROLLBACK statement */
-       if (gda_connection_statement_execute_non_select (cnc, internal_stmt [I_STMT_ROLLBACK], NULL, NULL, 
error) == -1)
+       if (gda_connection_statement_execute_non_select (cnc, priv->internal_stmt [I_STMT_ROLLBACK], NULL, 
NULL, error) == -1)
                return FALSE;
 
        return TRUE;
@@ -2393,8 +2411,9 @@ gda_postgres_provider_xa_prepare (GdaServerProvider *provider, GdaConnection *cn
        g_return_val_if_fail (GDA_IS_CONNECTION (cnc), FALSE);
        g_return_val_if_fail (gda_connection_get_provider (cnc) == provider, FALSE);
        g_return_val_if_fail (xid, FALSE);
+  GdaPostgresProviderPrivate *priv = gda_postgres_provider_get_instance_private (GDA_POSTGRES_PROVIDER 
(provider));
 
-       if (!gda_statement_get_parameters (internal_stmt [I_STMT_XA_PREPARE], &params, error))
+       if (!gda_statement_get_parameters (priv->internal_stmt [I_STMT_XA_PREPARE], &params, error))
                return FALSE;
        str = gda_xa_transaction_id_to_string (xid);
        if (!gda_set_set_holder_value (params, NULL, "xid", str)) {
@@ -2405,7 +2424,7 @@ gda_postgres_provider_xa_prepare (GdaServerProvider *provider, GdaConnection *cn
                return FALSE;
        }
        g_free (str);
-       affected = gda_connection_statement_execute_non_select (cnc, internal_stmt [I_STMT_XA_PREPARE], 
params,
+       affected = gda_connection_statement_execute_non_select (cnc, priv->internal_stmt [I_STMT_XA_PREPARE], 
params,
                                                                NULL, error);
        g_object_unref (params);
        if (affected == -1)
@@ -2429,8 +2448,9 @@ gda_postgres_provider_xa_commit (GdaServerProvider *provider, GdaConnection *cnc
        g_return_val_if_fail (GDA_IS_CONNECTION (cnc), FALSE);
        g_return_val_if_fail (gda_connection_get_provider (cnc) == provider, FALSE);
        g_return_val_if_fail (xid, FALSE);
+  GdaPostgresProviderPrivate *priv = gda_postgres_provider_get_instance_private (GDA_POSTGRES_PROVIDER 
(provider));
 
-       if (!gda_statement_get_parameters (internal_stmt [I_STMT_XA_PREPARE], &params, error))
+       if (!gda_statement_get_parameters (priv->internal_stmt [I_STMT_XA_PREPARE], &params, error))
                return FALSE;
        str = gda_xa_transaction_id_to_string (xid);
        if (!gda_set_set_holder_value (params, NULL, "xid", str)) {
@@ -2441,7 +2461,7 @@ gda_postgres_provider_xa_commit (GdaServerProvider *provider, GdaConnection *cnc
                return FALSE;
        }
        g_free (str);
-       affected = gda_connection_statement_execute_non_select (cnc, internal_stmt [I_STMT_XA_COMMIT], params,
+       affected = gda_connection_statement_execute_non_select (cnc, priv->internal_stmt [I_STMT_XA_COMMIT], 
params,
                                                                NULL, error);
        g_object_unref (params);
        if (affected == -1)
@@ -2464,8 +2484,9 @@ gda_postgres_provider_xa_rollback (GdaServerProvider *provider, GdaConnection *c
        g_return_val_if_fail (GDA_IS_CONNECTION (cnc), FALSE);
        g_return_val_if_fail (gda_connection_get_provider (cnc) == provider, FALSE);
        g_return_val_if_fail (xid, FALSE);
+  GdaPostgresProviderPrivate *priv = gda_postgres_provider_get_instance_private (GDA_POSTGRES_PROVIDER 
(provider));
 
-       if (!gda_statement_get_parameters (internal_stmt [I_STMT_XA_PREPARE], &params, error))
+       if (!gda_statement_get_parameters (priv->internal_stmt [I_STMT_XA_PREPARE], &params, error))
                return FALSE;
        str = gda_xa_transaction_id_to_string (xid);
        if (!gda_set_set_holder_value (params, NULL, "xid", str)) {
@@ -2476,7 +2497,7 @@ gda_postgres_provider_xa_rollback (GdaServerProvider *provider, GdaConnection *c
                return FALSE;
        }
        g_free (str);
-       affected = gda_connection_statement_execute_non_select (cnc, internal_stmt [I_STMT_XA_ROLLBACK], 
params,
+       affected = gda_connection_statement_execute_non_select (cnc, priv->internal_stmt 
[I_STMT_XA_ROLLBACK], params,
                                                                NULL, error);
        g_object_unref (params);
        if (affected == -1)
@@ -2498,8 +2519,9 @@ gda_postgres_provider_xa_recover (GdaServerProvider *provider, GdaConnection *cn
 
        g_return_val_if_fail (GDA_IS_CONNECTION (cnc), NULL);
        g_return_val_if_fail (gda_connection_get_provider (cnc) == provider, NULL);
+  GdaPostgresProviderPrivate *priv = gda_postgres_provider_get_instance_private (GDA_POSTGRES_PROVIDER 
(provider));
 
-       model = gda_connection_statement_execute_select (cnc, internal_stmt [I_STMT_XA_RECOVER], NULL, error);
+       model = gda_connection_statement_execute_select (cnc, priv->internal_stmt [I_STMT_XA_RECOVER], NULL, 
error);
        if (!model)
                return NULL;
        else {