add support for migrations

They're run from the UI thread so can even be interactive.

1 files changed, 72 insertions, 0 deletions

diff --git a/migration/migration.hpp b/migration/migration.hpp
new file mode 100644
index 00000000..b9c20f15
--- /dev/null
+++ b/migration/migration.hpp
@@ -0,0 +1,72 @@
+#pragma once
+
+#include <QString>
+#include <vector>
+
+#include "export.hpp"
+
+namespace migrations {
+
+class migration;
+class registrator;
+
+namespace detail {
+    class migrator final
+    {
+        using mm = migration*;
+        template<typename t> using vec_ = std::vector<t>;
+        using vstr = vec_<QString>;
+        using vec = vec_<mm>;
+        static vec& migrations();
+        static QString last_migration_time();
+        static QString time_after_migrations();
+        static void set_last_migration_time(const QString& val);
+        migrator() = delete;
+        static vec sorted_migrations();
+    public:
+        static vstr run();
+        static void register_migration(migration* m);
+        static void mark_config_as_not_needing_migration();
+    };
+
+    template<typename t>
+    struct registrator final
+    {
+        registrator()
+        {
+            static t m;
+            migrator::register_migration(static_cast<migration*>(&m));
+        }
+    };
+}
+
+#ifndef __COUNTER__
+#   error "oops, need __COUNTER__ extension for preprocessor"
+#endif
+
+#define OPENTRACK_MIGRATION(type) static ::migrations::detail::registrator<type> opentrack_migration_registrator__ ## __COUNTER__ ## _gensym;
+
+#ifdef Q_CREATOR_RUN
+#   pragma clang diagnostic ignored "-Wweak-vtables"
+#endif
+
+class migration
+{
+    migration& operator=(const migration&) = delete;
+    migration(const migration&) = delete;
+    migration& operator=(migration&&) = delete;
+    migration(migration&&) = delete;
+
+public:
+    migration();
+    virtual ~migration();
+    virtual QString unique_date() const = 0;
+    virtual QString name() const = 0;
+    virtual bool should_run() const = 0;
+    virtual void run() = 0;
+};
+
+}
+
+OPENTRACK_MIGRATION_EXPORT std::vector<QString> run_migrations();
+OPENTRACK_MIGRATION_EXPORT void mark_config_as_not_needing_migration();