add support for migrations

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

1 files changed, 129 insertions, 0 deletions

diff --git a/migration/migration.cpp b/migration/migration.cpp
new file mode 100644
index 00000000..6e54de19
--- /dev/null
+++ b/migration/migration.cpp
@@ -0,0 +1,129 @@
+#include "migration.hpp"
+
+#include "options/options.hpp"
+#include "compat/util.hpp"
+
+#include <QString>
+#include <QSettings>
+#include <QDebug>
+
+#include <memory>
+
+namespace migrations {
+
+namespace detail {
+
+void migrator::register_migration(migration* m)
+{
+    migrations().push_back(m);
+}
+
+migrator::vec& migrator::migrations()
+{
+    static vec ret;
+    return ret;
+}
+
+QString migrator::last_migration_time()
+{
+    QString ret;
+
+    std::shared_ptr<QSettings> s(options::group::ini_file());
+
+    s->beginGroup("migrations");
+    ret = s->value("last-migration-at", "19700101_00").toString();
+    s->endGroup();
+
+    return ret;
+}
+
+QString migrator::time_after_migrations()
+{
+    const vec list = sorted_migrations();
+
+    if (list.size() == 0u)
+        return QStringLiteral("19700101_00");
+
+    QString ret = list[list.size() - 1]->unique_date();
+    ret += QStringLiteral("~");
+
+    return ret;
+}
+
+void migrator::set_last_migration_time(const QString& val)
+{
+    std::shared_ptr<QSettings> s(options::group::ini_file());
+
+    s->beginGroup("migrations");
+    s->setValue("last-migration-at", val);
+    s->endGroup();
+}
+
+migrator::vec migrator::sorted_migrations()
+{
+    vec list(migrations());
+    std::sort(list.begin(), list.end(), [](const mm x, const mm y) { return x->unique_date() < y->unique_date(); });
+    return list;
+}
+
+std::vector<QString> migrator::run()
+{
+    vec migrations = sorted_migrations();
+    vstr done;
+
+    const QString last_migration = last_migration_time();
+
+    qDebug() << "migration: config" << options::group::ini_filename() << "time" << last_migration;
+
+    for (migration* m_ : migrations)
+    {
+        migration& m(*m_);
+
+        const QString date = m.unique_date();
+
+        if (date <= last_migration)
+            continue;
+
+        if (m.should_run())
+        {
+            m.run();
+            done.push_back(m.name());
+        }
+    }
+
+    mark_config_as_not_needing_migration();
+
+    if (done.size())
+    {
+        qDebug() << "migration: done" << done.size() << "units";
+        for (const QString& name : done)
+            qDebug() << "--" << name;
+        qDebug() << "";
+    }
+
+    return done;
+}
+
+}
+
+migration::migration() {}
+migration::~migration() {}
+
+} // ns
+
+std::vector<QString> run_migrations()
+{
+    return migrations::detail::migrator::run();
+}
+
+void mark_config_as_not_needing_migration()
+{
+    using m = migrations::detail::migrator;
+
+    m::mark_config_as_not_needing_migration();
+}
+
+void migrations::detail::migrator::mark_config_as_not_needing_migration()
+{
+    set_last_migration_time(time_after_migrations());
+}