SERVER-28297 Add IDL to LogicalSessionId class

src/mongo/db/SConscript

@@ -890,8 +890,10 @@ env.Library(
     target='logical_session_id',
     source=[
         'logical_session_id.cpp',
+        env.Idlc('logical_session_id.idl')[0],
     ],
     LIBDEPS=[
+        '$BUILD_DIR/mongo/idl/idl_parser',
         '$BUILD_DIR/mongo/util/uuid',
         '$BUILD_DIR/mongo/base',
     ],

src/mongo/db/logical_session_id.cpp

@@ -30,11 +30,23 @@
 
 #include "mongo/db/logical_session_id.h"
 
+#include "mongo/bson/bsonobjbuilder.h"
+#include "mongo/db/logical_session_id_gen.h"
 #include "mongo/util/assert_util.h"
 
 namespace mongo {
 
-LogicalSessionId::LogicalSessionId(UUID id) : _id(id) {}
+LogicalSessionId::LogicalSessionId() {
+    setId(UUID::gen());
+}
+
+LogicalSessionId::LogicalSessionId(UUID id) {
+    setId(std::move(id));
+}
+
+LogicalSessionId LogicalSessionId::gen() {
+    return {UUID::gen()};
+}
 
 StatusWith<LogicalSessionId> LogicalSessionId::parse(const TxnId& txnId) {
     // TODO: the TxnId class is not yet implemented.
@@ -50,8 +62,21 @@ StatusWith<LogicalSessionId> LogicalSessionId::parse(const std::string& s) {
     return LogicalSessionId{std::move(res.getValue())};
 }
 
+LogicalSessionId LogicalSessionId::parse(const BSONObj& doc) {
+    IDLParserErrorContext ctx("logical session id");
+    LogicalSessionId lsid;
+    lsid.parseProtected(ctx, doc);
+    return lsid;
+}
+
+BSONObj LogicalSessionId::toBSON() const {
+    BSONObjBuilder builder;
+    serialize(&builder);
+    return builder.obj();
+}
+
 std::string LogicalSessionId::toString() const {
-    return _id.toString();
+    return getId().toString();
 }
 
 }  // namespace mongo

src/mongo/db/logical_session_id.h

@@ -31,18 +31,26 @@
 #include <string>
 
 #include "mongo/base/status_with.h"
+#include "mongo/db/logical_session_id_gen.h"
 #include "mongo/util/uuid.h"
 
 namespace mongo {
 
+class BSONObjBuilder;
 class TxnId;
 
 /**
  * A 128-bit identifier for a logical session.
  */
-class LogicalSessionId {
+class LogicalSessionId : public Logical_session_id {
 public:
-    LogicalSessionId() = delete;
+    friend class Logical_session_id;
+    friend class Logical_session_record;
+
+    /**
+     * Create and return a new LogicalSessionId with a random UUID.
+     */
+    static LogicalSessionId gen();
 
     /**
      * Construct a new LogicalSessionId out of a txnId received with an operation.
@@ -55,13 +63,23 @@ public:
      */
     static StatusWith<LogicalSessionId> parse(const std::string& s);
 
+    /**
+     * Constructs a new LogicalSessionId out of a BSONObj. For IDL.
+     */
+    static LogicalSessionId parse(const BSONObj& doc);
+
     /**
      * Returns a string representation of this session id.
      */
     std::string toString() const;
 
+    /**
+     * Serialize this object to BSON.
+     */
+    BSONObj toBSON() const;
+
     inline bool operator==(const LogicalSessionId& rhs) const {
-        return _id == rhs._id;
+        return getId() == rhs.getId();
     }
 
     inline bool operator!=(const LogicalSessionId& rhs) const {
@@ -75,7 +93,7 @@ public:
      */
     struct Hash {
         std::size_t operator()(const LogicalSessionId& lsid) const {
-            return _hasher(lsid._id);
+            return _hasher(lsid.getId());
         }
 
     private:
@@ -84,7 +102,10 @@ public:
 
 
 private:
-    UUID _id;
+    /**
+     * This constructor exists for IDL only.
+     */
+    LogicalSessionId();
 
     /**
      * Construct a LogicalSessionId from a UUID.

src/mongo/db/logical_session_id.idl

@@ -0,0 +1,43 @@
+# 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/>.
+#
+
+# This IDL file describes the BSON format for a LogicalSessionId, and
+# handles the serialization to and deserialization from its BSON representation
+# for that class.
+
+global:
+  cpp_namespace: "mongo"
+  cpp_includes:
+    - "mongo/util/uuid.h"
+
+imports:
+  - "mongo/idl/basic_types.idl"
+
+types:
+
+  UUIDIDL:
+    description: "IDL representation of the UUID type"
+    bson_serialization_type: object
+    cpp_type: "mongo::UUID"
+    deserializer: "mongo::UUID::parse"
+    serializer: "mongo::UUID::toBSON"
+
+structs:
+
+  logical_session_id:
+    description: "A struct representing a LogicalSessionId"
+    strict: true
+    fields:
+      id: UUIDIDL

src/mongo/db/logical_session_id_test.cpp

@@ -30,6 +30,10 @@
 
 #include <string>
 
+#include "mongo/bson/bsonmisc.h"
+#include "mongo/bson/bsonobj.h"
+#include "mongo/bson/bsonobjbuilder.h"
+#include "mongo/bson/bsontypes.h"
 #include "mongo/db/logical_session_id.h"
 #include "mongo/unittest/unittest.h"
 #include "mongo/util/uuid.h"
@@ -53,5 +57,28 @@ TEST(LogicalSessionIdTest, ToAndFromStringTest) {
     ASSERT(!res.isOK());
 }
 
+TEST(LogicalSessionIdTest, FromBSONTest) {
+    auto uuid = UUID::gen();
+    auto bson = BSON("id" << uuid.toBSON());
+
+    auto lsid = LogicalSessionId::parse(bson);
+    ASSERT_EQUALS(lsid.toString(), uuid.toString());
+
+    // Dump back to BSON, make sure we get the same thing
+    auto bsonDump = lsid.toBSON();
+    ASSERT_EQ(bsonDump.woCompare(bson), 0);
+
+    // Try parsing mal-formatted bson objs
+    ASSERT_THROWS(LogicalSessionId::parse(BSON("hi"
+                                               << "there")),
+                  UserException);
+
+    // TODO: use these and add more once there is bindata
+    ASSERT_THROWS(LogicalSessionId::parse(BSON("id"
+                                               << "not a session id!")),
+                  UserException);
+    ASSERT_THROWS(LogicalSessionId::parse(BSON("id" << 14)), UserException);
+}
+
 }  // namespace
 }  // namespace mongo

src/mongo/util/uuid.cpp

@@ -81,6 +81,12 @@ StatusWith<UUID> UUID::parse(const std::string& s) {
     return UUID{std::move(uuid)};
 }
 
+UUID UUID::parse(const BSONObj& obj) {
+    auto res = parse(obj.getField("uuid"));
+    invariant(res.isOK());
+    return res.getValue();
+}
+
 bool UUID::isUUIDString(const std::string& s) {
     return std::regex_match(s, uuidRegex);
 }

src/mongo/util/uuid.h

@@ -48,7 +48,10 @@ class UUID {
     using UUIDStorage = std::array<unsigned char, 16>;
 
 public:
-    UUID() = delete;
+    /**
+     * This constructor exists for IDL only.
+     */
+    UUID() = default;
 
     /**
      * The number of bytes contained in a UUID.
@@ -72,6 +75,13 @@ public:
      */
     static StatusWith<UUID> parse(BSONElement from);
 
+    /**
+     * Parse a BSON document of the form { uuid: BinData(4, "...") }.
+     *
+     * For IDL.
+     */
+    static UUID parse(const BSONObj& obj);
+
     /**
      * Returns whether this string represents a valid UUID.
      */