Added ability to test the connection in the dialog where the connection details are entered.

pglablib/TestConnection.cpp

@@ -0,0 +1,58 @@
+#include "TestConnection.h"
+#include "ConnectionConfig.h"
+#include "Pgsql_Connection.h"
+#include "Pgsql_PgException.h"
+
+TestConnectionResult TestConnectionResult::Failed(QString msg)
+{
+    return TestConnectionResult(false, msg, {});
+}
+
+TestConnectionResult TestConnectionResult::Success(QStringList databases)
+{
+    return TestConnectionResult(true, "Test succesfull", databases);
+}
+
+bool TestConnectionResult::ok() const
+{
+    return Ok;
+}
+
+QString TestConnectionResult::message() const
+{
+    return Message;
+}
+
+const QStringList &TestConnectionResult::databases() const
+{
+    return Databases;
+}
+
+TestConnectionResult::TestConnectionResult(bool ok, QString msg, QStringList databases)
+    : Ok(ok)
+    , Message(msg)
+    , Databases(databases)
+{}
+
+TestConnectionResult TestConnection(const ConnectionConfig &cc)
+{
+    try {
+        Pgsql::Connection conn;
+        conn.connect(cc.connectionString());
+
+        auto result = conn.query(
+            "SELECT datname\n"
+            "  FROM pg_database\n"
+            "  WHERE datallowconn AND has_database_privilege(datname, 'connect')\n"
+            "  ORDER BY 1");
+
+        QStringList dbs;
+        for (auto row : result)
+            dbs.append(row.get(0));
+
+        return TestConnectionResult::Success(dbs);
+    }
+    catch (const Pgsql::PgException &ex) {
+        return TestConnectionResult::Failed(QString::fromUtf8(ex.what()));
+    }
+}