From e3349aefb0472751d75643bacf5667835824786f Mon Sep 17 00:00:00 2001
From: Christian Hohnstaedt <christian@hohnstaedt.de>
Date: Thu, 22 Mar 2018 20:24:01 +0100
Subject: [PATCH] Accept driver that don't support transactions

Improve report of transaction errors.
---
 lib/sql.cpp        | 17 +++++++++++++++--
 lib/sql.h          |  5 +++++
 widgets/OpenDb.cpp |  8 ++++++++
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/lib/sql.cpp b/lib/sql.cpp
index f3535e38..09fe5a78 100644
--- a/lib/sql.cpp
+++ b/lib/sql.cpp
@@ -10,9 +10,11 @@
 #include "base.h"
 #include "sql.h"
 #include "settings.h"
+#include "widgets/MainWindow.h"
 
 int DbTransaction::mutex;
 int DbTransaction::error;
+bool DbTransaction::hasTransaction;
 QList<quint64> DbTransaction::items;
 
 quint64 DatabaseStamp;
@@ -40,7 +42,14 @@ bool DbTransaction::begin(const char *file, int line)
 	mutex++;
 	has_begun = true;
 	debug("Begin", file, line);
-	return mutex > 1 ? true : QSqlDatabase::database().transaction();
+	if (mutex > 1 || !hasTransaction)
+		return true;
+
+	QSqlDatabase db = QSqlDatabase::database();
+	bool ret = db.transaction();
+	if (!ret)
+		MainWindow::dbSqlError(db.lastError());
+	return ret;
 }
 
 bool DbTransaction::finish(const char *oper, const char *file, int line)
@@ -81,7 +90,11 @@ bool DbTransaction::finish(const char *oper, const char *file, int line)
 	}
 	mutex--;
 	items.clear();
-	return db.commit();
+
+	bool ret = db.commit();
+	if (!ret)
+		MainWindow::dbSqlError(db.lastError());
+	return ret;
 }
 
 bool DbTransaction::commit(const char *file, int line)
diff --git a/lib/sql.h b/lib/sql.h
index 3e26a2f3..87239af8 100644
--- a/lib/sql.h
+++ b/lib/sql.h
@@ -22,6 +22,7 @@ class DbTransaction
 		static int mutex;
 		static int error;
 		static QList<quint64> items;
+		static bool hasTransaction;
 		bool has_begun;
 		void debug(const char *func, const char *file, int line);
 		bool finish(const char *oper, const char *file, int line);
@@ -41,6 +42,10 @@ class DbTransaction
 		{
 			items << v.toULongLong();
 		}
+		static void setHasTransaction(bool trans)
+		{
+			hasTransaction = trans;
+		}
 };
 
 #define Transaction DbTransaction __trans
diff --git a/widgets/OpenDb.cpp b/widgets/OpenDb.cpp
index e3d0bfc6..4ca6f8a4 100644
--- a/widgets/OpenDb.cpp
+++ b/widgets/OpenDb.cpp
@@ -197,7 +197,15 @@ bool OpenDb::_openDatabase(QString connName, QString pass) const
 	QSqlError e = db.lastError();
 	if (!e.isValid() || e.type() != QSqlError::ConnectionError ||
 			db.isOpen())
+	{
+		bool hasTrans = QSqlDatabase::database()
+			.driver()->hasFeature(QSqlDriver::Transactions);
+		DbTransaction::setHasTransaction(hasTrans);
+		if (!hasTrans) {
+			XCA_WARN(tr("The database driver does not support transactions. This may happen if the client and server have different versions. Continue with care."));
+		}
 		return true;
+	}
 	XSqlQuery::clearTablePrefix();
 	db.close();
 	return false;