Open a database for writing, create a table

wdmtg.vala

@@ -290,6 +290,52 @@ namespace Wdmtg {
     set_idle_alarm (ref idle_alarm_inactive,
       X.Sync.TestType.PositiveComparison, idle_timeout);
 
+    var data_path = Path.build_filename (Environment.get_user_data_dir (),
+      Config.PROJECT_NAME);
+    DirUtils.create_with_parents (data_path, 0755);
+
+    Sqlite.Database db;
+    var db_path = Path.build_filename (data_path, "db.sqlite");
+    int rc = Sqlite.Database.open (db_path, out db);
+    if (rc != Sqlite.OK)
+      exit_fatal ("%s: %s", db_path, db.errmsg ());
+
+    // This shouldn't normally happen but external applications may decide
+    // to read things out, and mess with us.  When that takes too long, we may
+    // a/ wait for it to finish, b/ start with a whole-database lock or, even
+    // more simply, c/ crash on the BUSY error.
+    db.busy_timeout (1000);
+
+    string errmsg;
+    if ((rc = db.exec ("BEGIN", null, out errmsg)) != Sqlite.OK)
+      exit_fatal ("%s: %s", db_path, errmsg);
+
+    Sqlite.Statement stmt;
+    if ((rc = db.prepare_v2 ("PRAGMA user_version", -1, out stmt, null))
+      != Sqlite.OK)
+      exit_fatal ("%s: %s", db_path, db.errmsg ());
+    if ((rc = stmt.step ()) != Sqlite.ROW || stmt.data_count () != 1)
+      exit_fatal ("%s: %s", db_path, "cannot retrieve user version");
+
+    var user_version = stmt.column_int (0);
+    if (user_version == 0) {
+      if ((rc = db.exec ("""CREATE TABLE events (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        timestamp INTEGER,
+        title TEXT,
+        idle BOOLEAN
+      )""", null, out errmsg)) != Sqlite.OK)
+        exit_fatal ("%s: %s", db_path, errmsg);
+
+      if ((rc = db.exec ("PRAGMA user_version = 1", null, out errmsg))
+        != Sqlite.OK)
+        exit_fatal ("%s: %s", db_path, errmsg);
+    } else if (user_version != 1) {
+      exit_fatal ("%s: unsupported DB version: %d", db_path, user_version);
+    }
+    if ((rc = db.exec ("COMMIT", null, out errmsg)) != Sqlite.OK)
+      exit_fatal ("%s: %s", db_path, errmsg);
+
     var loop = new MainLoop ();
     var channel = new IOChannel.unix_new (dpy.connection_number ());
     channel.add_watch (IOCondition.IN, (source, condition) => {