SERVER-28296 Implement a LogicalSessionId class

2 files changed, 160 insertions, 0 deletions

diff --git a/src/mongo/db/logical_session_id.cpp b/src/mongo/db/logical_session_id.cpp
new file mode 100644
index 00000000000..53450eab7e4
--- /dev/null
+++ b/src/mongo/db/logical_session_id.cpp
@@ -0,0 +1,57 @@
+/**
+ *    Copyright (C) 2017 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program 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 Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/db/logical_session_id.h"
+
+#include "mongo/util/assert_util.h"
+
+namespace mongo {
+
+LogicalSessionId::LogicalSessionId(UUID id) : _id(id) {}
+
+StatusWith<LogicalSessionId> LogicalSessionId::parse(const TxnId& txnId) {
+    // TODO: the TxnId class is not yet implemented.
+    MONGO_UNREACHABLE;
+}
+
+StatusWith<LogicalSessionId> LogicalSessionId::parse(const std::string& s) {
+    auto res = UUID::parse(s);
+    if (!res.isOK()) {
+        return res.getStatus();
+    }
+
+    return LogicalSessionId{std::move(res.getValue())};
+}
+
+std::string LogicalSessionId::toString() const {
+    return _id.toString();
+}
+
+}  // namespace mongo
diff --git a/src/mongo/db/logical_session_id.h b/src/mongo/db/logical_session_id.h
new file mode 100644
index 00000000000..20e6d8e9547
--- /dev/null
+++ b/src/mongo/db/logical_session_id.h
@@ -0,0 +1,103 @@
+/**
+ *    Copyright (C) 2017 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program 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 Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+#include <string>
+
+#include "mongo/base/status_with.h"
+#include "mongo/util/uuid.h"
+
+namespace mongo {
+
+class TxnId;
+
+/**
+ * A 128-bit identifier for a logical session.
+ */
+class LogicalSessionId {
+public:
+    LogicalSessionId() = delete;
+
+    /**
+     * Construct a new LogicalSessionId out of a txnId received with an operation.
+     */
+    static StatusWith<LogicalSessionId> parse(const TxnId& txnId);
+
+    /**
+     * If the given string represents a valid LogicalSessionId, constructs and returns,
+     * the id, otherwise returns an error.
+     */
+    static StatusWith<LogicalSessionId> parse(const std::string& s);
+
+    /**
+     * Returns a string representation of this session id.
+     */
+    std::string toString() const;
+
+    inline bool operator==(const LogicalSessionId& rhs) const {
+        return _id == rhs._id;
+    }
+
+    inline bool operator!=(const LogicalSessionId& rhs) const {
+        return !(*this == rhs);
+    }
+
+    /**
+     * Custom hasher so LogicalSessionIds can be used in unordered data structures.
+     *
+     * ex: std::unordered_set<LogicalSessionId, LogicalSessionId::Hash> lsidSet;
+     */
+    struct Hash {
+        std::size_t operator()(const LogicalSessionId& lsid) const {
+            return _hasher(lsid._id);
+        }
+
+    private:
+        UUID::Hash _hasher;
+    };
+
+
+private:
+    UUID _id;
+
+    /**
+     * Construct a LogicalSessionId from a UUID.
+     */
+    LogicalSessionId(UUID id);
+};
+
+inline std::ostream& operator<<(std::ostream& s, const LogicalSessionId& lsid) {
+    return (s << lsid.toString());
+}
+
+inline StringBuilder& operator<<(StringBuilder& s, const LogicalSessionId& lsid) {
+    return (s << lsid.toString());
+}
+
+}  // namespace mongo