Make opening dbis non-racy

Dbis can only be opened by one thread and should then
be shared accross all threads after committing the transaction
to create the dbi.
This requires us to initially open all db's, which in turn requires us
to know the correct flags.

This patch stores the flags to open each db in a separate db,
and then opens up all databases on initial start.
If a new database is created that dbi is as well shared as soon as
the transaction is committed (before the dbi is private to the
transaction).

1 files changed, 36 insertions, 0 deletions

diff --git a/tests/storagetest.cpp b/tests/storagetest.cpp
index 5a517c7..7202628 100644
--- a/tests/storagetest.cpp
+++ b/tests/storagetest.cpp
@@ -451,6 +451,42 @@ private slots:
         db.findLatest(uid, [&](const QByteArray &key, const QByteArray &value) { result = value; });
         QCOMPARE(result, QByteArray("value2"));
     }
+
+    void testTransactionVisibility()
+    {
+        auto readValue = [](const Sink::Storage::DataStore::NamedDatabase &db, const QByteArray) {
+            QByteArray result;
+            db.scan("key1", [&](const QByteArray &, const QByteArray &value) {
+                result = value;
+                return true;
+            });
+            return result;
+        };
+        {
+            Sink::Storage::DataStore store(testDataPath, dbName, Sink::Storage::DataStore::ReadWrite);
+            auto transaction = store.createTransaction(Sink::Storage::DataStore::ReadWrite);
+
+            auto db = transaction.openDatabase("testTransactionVisibility", nullptr, false);
+            db.write("key1", "foo");
+            QCOMPARE(readValue(db, "key1"), QByteArray("foo"));
+
+            {
+                auto transaction2 = store.createTransaction(Sink::Storage::DataStore::ReadOnly);
+                auto db2 = transaction2
+                    .openDatabase("testTransactionVisibility", nullptr, false);
+                QCOMPARE(readValue(db2, "key1"), QByteArray());
+            }
+            transaction.commit();
+            {
+                auto transaction2 = store.createTransaction(Sink::Storage::DataStore::ReadOnly);
+                auto db2 = transaction2
+                    .openDatabase("testTransactionVisibility", nullptr, false);
+                QCOMPARE(readValue(db2, "key1"), QByteArray("foo"));
+            }
+
+        }
+    }
+
 };
 
 QTEST_MAIN(StorageTest)