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// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef OSP_PUBLIC_PROTOCOL_CONNECTION_H_
#define OSP_PUBLIC_PROTOCOL_CONNECTION_H_
#include <cstddef>
#include <cstdint>
#include <type_traits>
#include "osp/msgs/osp_messages.h"
#include "platform/base/error.h"
#include "util/logging.h"
namespace openscreen {
template <typename T>
using MessageEncodingFunction =
std::add_pointer_t<bool(const T&, msgs::CborEncodeBuffer*)>;
class Error;
struct NetworkMetrics;
// Represents an embedder's view of a connection between an Open Screen
// controller and a receiver. Both the controller and receiver will have a
// ProtocolConnection object, although the information known about the other
// party may not be symmetrical.
//
// A ProtocolConnection supports multiple protocols defined by the Open Screen
// standard and can be extended by embedders with additional protocols.
//
// TODO(jophba): move to sharing underlying QUIC connections between multiple
// instances of ProtocolConnection.
class ProtocolConnection {
public:
class Observer {
public:
virtual ~Observer() = default;
// Called when |connection| is no longer available, either because the
// underlying transport was terminated, the underying system resource was
// closed, or data can no longer be exchanged.
virtual void OnConnectionClosed(const ProtocolConnection& connection) = 0;
};
ProtocolConnection(uint64_t endpoint_id, uint64_t connection_id);
virtual ~ProtocolConnection() = default;
// TODO(mfoltz): Define extension API exposed to embedders. This would be
// used, for example, to query for and implement vendor-specific protocols
// alongside the Open Screen Protocol.
// NOTE: ProtocolConnection instances that are owned by clients will have a
// ServiceInfo attached with data from discovery and QUIC connection
// establishment. What about server connections? We probably want to have
// two different structures representing what the client and server know about
// a connection.
void SetObserver(Observer* observer);
template <typename T>
Error WriteMessage(const T& message, MessageEncodingFunction<T> encoder) {
msgs::CborEncodeBuffer buffer;
if (!encoder(message, &buffer)) {
OSP_LOG_WARN << "failed to properly encode presentation message";
return Error::Code::kParseError;
}
Write(buffer.data(), buffer.size());
return Error::None();
}
// TODO(btolsch): This should be derived from the handshake auth identifier
// when that is finalized and implemented.
uint64_t endpoint_id() const { return endpoint_id_; }
uint64_t id() const { return id_; }
virtual void Write(const uint8_t* data, size_t data_size) = 0;
virtual void CloseWriteEnd() = 0;
protected:
uint64_t endpoint_id_;
uint64_t id_;
Observer* observer_ = nullptr;
};
class ProtocolConnectionServiceObserver {
public:
// Called when the state becomes kRunning.
virtual void OnRunning() = 0;
// Called when the state becomes kStopped.
virtual void OnStopped() = 0;
// Called when metrics have been collected by the service.
virtual void OnMetrics(const NetworkMetrics& metrics) = 0;
// Called when an error has occurred.
virtual void OnError(const Error& error) = 0;
protected:
virtual ~ProtocolConnectionServiceObserver() = default;
};
} // namespace openscreen
#endif // OSP_PUBLIC_PROTOCOL_CONNECTION_H_
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