SERVER-28294 Add a standalone UUID library to utilities

1 files changed, 126 insertions, 0 deletions

diff --git a/src/mongo/util/uuid.h b/src/mongo/util/uuid.h
new file mode 100644
index 00000000000..5127932dd6a
--- /dev/null
+++ b/src/mongo/util/uuid.h
@@ -0,0 +1,126 @@
+/**
+ *    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 <functional>
+#include <string>
+
+#include <third_party/murmurhash3/MurmurHash3.h>
+
+#include "mongo/base/status_with.h"
+#include "mongo/bson/bsonelement.h"
+#include "mongo/bson/bsonobj.h"
+
+namespace mongo {
+
+/**
+ * A UUID is a 128-bit unique identifier, per RFC 4122, v4, using
+ * a secure random number generator.
+ */
+class UUID {
+public:
+    UUID() = delete;
+
+    /**
+     * The number of bytes contained in a UUID.
+     */
+    static const int kNumBytes;
+
+    /**
+     * Generate a new random v4 UUID per RFC 4122.
+     */
+    static UUID gen();
+
+    /**
+     * If the given string represents a valid UUID, constructs and returns the UUID,
+     * otherwise returns an error.
+     */
+    static StatusWith<UUID> parse(const std::string& s);
+
+    /**
+     * If the given BSONElement represents a valid UUID, constructs and returns the UUID,
+     * otherwise returns an error.
+     */
+    static StatusWith<UUID> parse(BSONElement from);
+
+    /**
+     * Returns whether this string represents a valid UUID.
+     */
+    static bool isUUIDString(const std::string& s);
+
+    /**
+     * Return a BSON object of the form { uuid: BinData(4, "...") }.
+     */
+    BSONObj toBSON() const;
+
+    /**
+     * Return a string representation of this UUID, in hexadecimal,
+     * as per RFC 4122:
+     *
+     * 4 Octets - 2 Octets - 2 Octets - 2 Octets - 6 Octets
+     */
+    std::string toString() const;
+
+    inline bool operator==(const UUID& rhs) const {
+        return !memcmp(&_uuid, &rhs._uuid, sizeof(_uuid));
+    }
+
+    inline bool operator!=(const UUID& rhs) const {
+        return !(*this == rhs);
+    }
+
+    /**
+     * Custom hasher so UUIDs can be used in unordered data structures.
+     *
+     * ex: std::unordered_set<UUID, UUID::Hash> uuidSet;
+     */
+    struct Hash {
+        std::size_t operator()(const UUID& uuid) const {
+            uint32_t hash;
+            MurmurHash3_x86_32(uuid._uuid.data(), UUID::kNumBytes, 0, &hash);
+            return hash;
+        }
+    };
+
+private:
+    using UUIDStorage = std::array<unsigned char, 16>;
+    UUID(const UUIDStorage& uuid) : _uuid(uuid) {}
+
+    UUIDStorage _uuid;  // UUID in network byte order
+};
+
+inline std::ostream& operator<<(std::ostream& s, const UUID& uuid) {
+    return (s << uuid.toString());
+}
+
+inline StringBuilder& operator<<(StringBuilder& s, const UUID& uuid) {
+    return (s << uuid.toString());
+}
+
+}  // namespace mongo