Add persistent_data/lock_tracker for more sanity checking.

persistent-data/lock_tracker.cc

@@ -0,0 +1,97 @@
+// Copyright (C) 2012 Red Hat, Inc. All rights reserved.
+//
+// This file is part of the thin-provisioning-tools source.
+//
+// thin-provisioning-tools is free software: you can redistribute it
+// and/or modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// thin-provisioning-tools is distributed in the hope that it will be
+// useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with thin-provisioning-tools.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+#include "lock_tracker.h"
+
+#include <stdexcept>
+
+using namespace persistent_data;
+using namespace std;
+
+//----------------------------------------------------------------
+
+lock_tracker::lock_tracker(uint64_t low, uint64_t high)
+	: low_(low),
+	  high_(high)
+{
+}
+
+void
+lock_tracker::read_lock(uint64_t key)
+{
+	check_key(key);
+
+	LockMap::const_iterator it = locks_.find(key);
+	if (found(it)) {
+		if (it->second < 0)
+			throw runtime_error("already write locked");
+
+		locks_.insert(make_pair(key, it->second + 1));
+
+	} else
+		locks_.insert(make_pair(key, 1));
+}
+
+void
+lock_tracker::write_lock(uint64_t key)
+{
+	check_key(key);
+
+	LockMap::const_iterator it = locks_.find(key);
+	if (found(it))
+		throw runtime_error("already locked");
+
+	locks_.insert(make_pair(key, -1));
+}
+
+void
+lock_tracker::unlock(uint64_t key)
+{
+	check_key(key);
+
+	LockMap::const_iterator it = locks_.find(key);
+	if (!found(it))
+		throw runtime_error("not locked");
+
+	if (it->second > 1)
+		locks_.insert(make_pair(key, it->second - 1));
+	else
+		locks_.erase(key);
+}
+
+bool
+lock_tracker::found(LockMap::const_iterator it) const
+{
+	return it != locks_.end();
+}
+
+bool
+lock_tracker::valid_key(uint64_t key) const
+{
+	return (key >= low_ && key <= high_);
+}
+
+void
+lock_tracker::check_key(uint64_t key) const
+{
+	if (!valid_key(key))
+		throw runtime_error("invalid key");
+}
+
+//----------------------------------------------------------------
+