lib-sql: sqlite - Keep a persistent cache of used sql databases

diff --git a/src/lib-sql/driver-sqlite.c b/src/lib-sql/driver-sqlite.c
index d4c955e2b2603acb8c94fb0f7dd8121f160076ed..18ac220f09040a6b4c01d152aa635b05d387073a 100644 (file)
--- a/src/lib-sql/driver-sqlite.c
+++ b/src/lib-sql/driver-sqlite.c
@@ -81,6 +81,8 @@ extern const struct sql_db driver_sqlite_db;
 extern const struct sql_result driver_sqlite_result;
 extern const struct sql_result driver_sqlite_error_result;
 
+static ARRAY(struct sqlite_db *) sqlite_db_cache;
+
 static struct event_category event_category_sqlite = {
        .parent = &event_category_sql,
        .name = "sqlite"
@@ -146,7 +148,20 @@ static int driver_sqlite_connect(struct sql_db *_db)
        return -1;
 }
 
-static struct sql_db *
+static struct sqlite_db *
+driver_sqlite_db_cache_find(const struct sqlite_settings *set)
+{
+       struct sqlite_db *db;
+
+       array_foreach_elem(&sqlite_db_cache, db) {
+               if (settings_equal(&sqlite_setting_parser_info,
+                                  set, db->set, NULL))
+                       return db;
+       }
+       return NULL;
+}
+
+static struct sqlite_db *
 driver_sqlite_init_common(struct event *event,
                          const struct sqlite_settings *set)
 {
@@ -159,7 +174,7 @@ driver_sqlite_init_common(struct event *event,
        db->api.event = event_create(event);
        event_add_category(db->api.event, &event_category_sqlite);
        event_set_append_log_prefix(db->api.event, "sqlite: ");
-       return &db->api;
+       return db;
 }
 
 static int
@@ -171,8 +186,20 @@ driver_sqlite_init_v(struct event *event, struct sql_db **db_r,
        if (settings_get(event, &sqlite_setting_parser_info, 0,
                         &set, error_r) < 0)
                return -1;
-       *db_r = driver_sqlite_init_common(event, set);
-       sql_init_common(*db_r);
+
+       struct sqlite_db *db = driver_sqlite_db_cache_find(set);
+       if (db != NULL)
+               settings_free(set);
+       else {
+               db = driver_sqlite_init_common(event, set);
+               sql_init_common(&db->api);
+               array_push_back(&sqlite_db_cache, &db);
+               /* Add an extra reference to the db, so it won't be freed while
+                  it's still in the cache array. */
+       }
+       db->api.refcount++;
+
+       *db_r = &db->api;
        return 0;
 }
 
@@ -239,7 +266,9 @@ driver_sqlite_init_full_v(const struct sql_legacy_settings *legacy_set,
                return -1;
        }
 
-       *db_r = driver_sqlite_init_common(legacy_set->event_parent, set);
+       struct sqlite_db *db =
+               driver_sqlite_init_common(legacy_set->event_parent, set);
+       *db_r = &db->api;
        return 0;
 }
 
@@ -766,11 +795,19 @@ const char *driver_sqlite_version = DOVECOT_ABI_VERSION;
 
 void driver_sqlite_init(void)
 {
+       i_array_init(&sqlite_db_cache, 4);
        sql_driver_register(&driver_sqlite_db);
 }
 
 void driver_sqlite_deinit(void)
 {
+       struct sqlite_db *db;
+
+       array_foreach_elem(&sqlite_db_cache, db) {
+               struct sql_db *_db = &db->api;
+               sql_unref(&_db);
+       }
+       array_free(&sqlite_db_cache);
        sql_driver_unregister(&driver_sqlite_db);
 }