SERVER-23638 Headers for new ingress networking types

1 files changed, 152 insertions, 0 deletions

diff --git a/src/mongo/transport/transport_layer.h b/src/mongo/transport/transport_layer.h
new file mode 100644
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+++ b/src/mongo/transport/transport_layer.h
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+/**
+ *    Copyright (C) 2016 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 "mongo/base/status.h"
+#include "mongo/stdx/functional.h"
+#include "mongo/transport/session.h"
+#include "mongo/transport/ticket.h"
+#include "mongo/util/net/message.h"
+#include "mongo/util/time_support.h"
+
+namespace mongo {
+namespace transport {
+
+/**
+ * The TransportLayer moves Messages between transport::Endpoints and the database.
+ * This class owns an Acceptor that generates new endpoints from which it can
+ * source Messages.
+ *
+ * The TransportLayer creates Session objects and maps them internally to
+ * endpoints. New Sessions are passed to the database (via a ServiceEntryPoint)
+ * to be run. The database must then call additional methods on the TransportLayer
+ * to manage the Session in a get-Message, handle-Message, return-Message cycle.
+ * It must do this on its own thread(s).
+ *
+ * References to the TransportLayer should be stored on service context objects.
+ */
+class TransportLayer {
+    MONGO_DISALLOW_COPYING(TransportLayer);
+
+public:
+    virtual ~TransportLayer() = default;
+
+    /**
+     * Source (receive) a new Message for this Session.
+     *
+     * This method returns a work Ticket. The caller must complete the Ticket by
+     * passing it to either TransportLayer::wait() or TransportLayer::asyncWait().
+     *
+     * If an expiration date is given, the returned Ticket will expire at that time.
+     *
+     * When run, the returned Ticket will be exchanged for a Status. If the
+     * TransportLayer is unable to source a Message, this will be a failed status,
+     * and the passed-in Message buffer may be left in an invalid state.
+     */
+    virtual Ticket sourceMessage(const Session& session,
+                                 Message* message,
+                                 Date_t expiration = Ticket::kNoExpirationDate) = 0;
+
+    /**
+     * Sink (send) a new Message for this Session. This method should be used
+     * to send replies to a given host.
+     *
+     * This method returns a work Ticket. The caller must complete the Ticket by
+     * passing it to either TransportLayer::wait() or TransportLayer::asyncWait().
+     *
+     * If an expiration date is given, the returned Ticket will expire at that time.
+     *
+     * When run, the returned Ticket will be exchanged for a Status. If the
+     * TransportLayer is unable to sink the Message, this will be a failed status.
+     *
+     * This method does NOT take ownership of the sunk Message, which must be cleaned
+     * up by the caller.
+     */
+    virtual Ticket sinkMessage(const Session& session,
+                               const Message& message,
+                               Date_t expiration = Ticket::kNoExpirationDate) = 0;
+
+    /**
+     * Perform a synchronous wait on the given work Ticket. When this call returns,
+     * the Ticket will have been completed. A call to wait() consumes the Ticket.
+     *
+     * This thread may be used by the TransportLayer to run other Tickets that were
+     * enqueued prior to this call.
+     */
+    virtual Status wait(Ticket ticket) = 0;
+
+    /**
+     * Callback for Tickets that are run via asyncWait().
+     */
+    using TicketCallback = stdx::function<void(Status)>;
+
+    /**
+     * Perform an asynchronous wait on the given work Ticket. Once the Ticket has been
+     * completed, the passed-in callback will be invoked.
+     *
+     * This thread will not be used by the TransportLayer to perform work. The callback
+     * passed to asyncWait() may be run on any thread.
+     */
+    virtual void asyncWait(Ticket ticket, TicketCallback callback) = 0;
+
+    /**
+     * End the given Session. Tickets for this Session that have already been
+     * started via wait() or asyncWait() will complete, but may return a failed Status.
+     * Future calls to wait() or asyncWait() for this Session will fail. If this
+     * TransportLayer implementation is networked, any connections for this Session will
+     * be closed.
+     *
+     * ~Session() will automatically call end() with itself.
+     *
+     * This method is idempotent and synchronous.
+     */
+    virtual void end(const Session& session) = 0;
+
+    /**
+     * End all active sessions in the TransportLayer. Tickets that have already been
+     * started via wait() or asyncWait() will complete, but may return a failed Status.
+     * This method is synchronous and will not return until all sessions have ended.
+     */
+    virtual void endAllSessions() = 0;
+
+    /**
+     * Shut the TransportLayer down. After this point, the TransportLayer will
+     * end all active sessions and won't accept new transport::Endpoints. Any
+     * future calls to wait() or asyncWait() will fail. This method is synchronous and
+     * will not return until all sessions have ended and any network connections have been
+     * closed.
+     */
+    virtual void shutdown() = 0;
+
+protected:
+    TransportLayer() = default;
+};
+
+}  // namespace transport
+}  // namespace mongo