Sessions to manage db open state

src/session.cpp

@@ -0,0 +1,73 @@
+/*
+* LMDB Abstraction Layer.
+ * Copyright (C) 2023  Yury Gubich <blue@macaw.me>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "session.h"
+
+LMDBAL::Session::Session():
+    parent(nullptr) {}
+
+LMDBAL::Session::Session(Base* parent):
+    parent(parent)
+{
+    parent->registerSession(this);
+}
+
+LMDBAL::Session::Session(Session&& other):
+    parent(other.parent)
+{
+    if (parent)
+        parent->replaceSession(&other, this);
+}
+
+LMDBAL::Session::~Session() {
+    if (parent)
+        parent->unregisterSession(this);
+}
+
+LMDBAL::Session& LMDBAL::Session::operator = (Session&& other) {
+    if (parent)
+        if (other.parent)
+            parent->unregisterSession(&other);
+        else
+            parent->unregisterSession(this);
+    else
+        if (other.parent)
+            other.parent->replaceSession(&other, this);
+
+    parent = other.parent;
+    other.terminate();
+
+    return *this;
+}
+
+void LMDBAL::Session::close() {
+    if (!parent)
+        return;
+
+    parent->unregisterSession(this);
+    terminate();
+}
+
+bool LMDBAL::Session::opened() const {
+    return parent != nullptr;
+}
+
+void LMDBAL::Session::terminate() {
+    parent = nullptr;
+}
+