Roll forward to cl/331498408

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: If30a8df80799adec3aafba5b8dd4c539fc21e16d

cpp/core_v2/internal/bwu_handler.h

@@ -0,0 +1,74 @@
+#ifndef CORE_V2_INTERNAL_BWU_HANDLER_H_
+#define CORE_V2_INTERNAL_BWU_HANDLER_H_
+
+#include "core_v2/internal/client_proxy.h"
+#include "core_v2/internal/endpoint_channel.h"
+#include "core_v2/internal/offline_frames.h"
+#include "platform_v2/public/count_down_latch.h"
+#include "proto/connections_enums.pb.h"
+
+namespace location {
+namespace nearby {
+namespace connections {
+
+using BwuNegotiationFrame = BandwidthUpgradeNegotiationFrame;
+
+// Defines the set of methods that need to be implemented to handle the
+// per-Medium-specific operations needed to upgrade an EndpointChannel.
+class BwuHandler {
+ public:
+  using UpgradePathInfo = parser::UpgradePathInfo;
+
+  virtual ~BwuHandler() = default;
+
+  // Called by the Initiator to setup the upgraded medium for this endpoint (if
+  // that hasn't already been done), and returns a serialized UpgradePathInfo
+  // that can be sent to the Responder.
+  // @BwuHandlerThread
+  virtual ByteArray InitializeUpgradedMediumForEndpoint(
+      ClientProxy* client, const std::string& service_id,
+      const std::string& endpoint_id) = 0;
+  // Called to revert any state changed by the Initiator to setup the upgraded
+  // medium for an endpoint.
+  // @BwuHandlerThread
+  virtual void Revert() = 0;
+
+  // Called by the Responder to setup the upgraded medium for this endpoint (if
+  // that hasn't already been done) using the UpgradePathInfo sent by the
+  // Initiator, and returns a new EndpointChannel for the upgraded medium.
+  // @BwuHandlerThread
+  virtual std::unique_ptr<EndpointChannel> CreateUpgradedEndpointChannel(
+      ClientProxy* client, const std::string& service_id,
+      const std::string& endpoint_id,
+      const UpgradePathInfo& upgrade_path_info) = 0;
+  // Returns the upgrade medium of the BwuHandler.
+  // @BwuHandlerThread
+  virtual Medium GetUpgradeMedium() const = 0;
+  virtual void OnEndpointDisconnect(ClientProxy* client,
+                                    const std::string& endpoint_id) = 0;
+
+  class IncomingSocket {
+   public:
+    virtual ~IncomingSocket() = default;
+
+    virtual std::string ToString() = 0;
+    virtual void Close() = 0;
+  };
+
+  struct IncomingSocketConnection {
+    std::unique_ptr<IncomingSocket> socket;
+    std::unique_ptr<EndpointChannel> channel;
+  };
+
+  struct BwuNotifications {
+    std::function<void(ClientProxy* client,
+                       IncomingSocketConnection* connection)>
+        incoming_connection_cb;
+  };
+};
+
+}  // namespace connections
+}  // namespace nearby
+}  // namespace location
+
+#endif  // CORE_V2_INTERNAL_BWU_HANDLER_H_