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// Copyright 2020 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 DISCOVERY_PUBLIC_DNS_SD_SERVICE_PUBLISHER_H_
#define DISCOVERY_PUBLIC_DNS_SD_SERVICE_PUBLISHER_H_
#include <string>
#include <utility>
#include "discovery/dnssd/public/dns_sd_instance.h"
#include "discovery/dnssd/public/dns_sd_instance_endpoint.h"
#include "discovery/dnssd/public/dns_sd_publisher.h"
#include "discovery/dnssd/public/dns_sd_service.h"
#include "platform/base/error.h"
#include "util/osp_logging.h"
namespace openscreen {
namespace discovery {
// This class represents a top-level discovery API which sits on top of DNS-SD.
// The main purpose of this class is to hide DNS-SD internals from embedders who
// do not care about the specific functionality and do not need to understand
// DNS-SD Internals.
// T is the service-specific type which stores information regarding a specific
// service instance.
// NOTE: This class is not thread-safe and calls will be made to DnsSdService in
// the same sequence and on the same threads from which these methods are
// called. This is to avoid forcing design decisions on embedders who write
// their own implementations of the DNS-SD layer.
template <typename T>
class DnsSdServicePublisher : public DnsSdPublisher::Client {
public:
// This function type is responsible for converting from a T type to a
// DNS service instance (to publish to the network).
using ServiceInstanceConverter = std::function<DnsSdInstance(const T&)>;
DnsSdServicePublisher(DnsSdService* service,
std::string service_name,
ServiceInstanceConverter conversion)
: conversion_(conversion),
service_name_(std::move(service_name)),
publisher_(service ? service->GetPublisher() : nullptr) {
OSP_DCHECK(publisher_);
}
~DnsSdServicePublisher() = default;
Error Register(const T& service) {
if (!service.IsValid()) {
return Error::Code::kParameterInvalid;
}
DnsSdInstance instance = conversion_(service);
return publisher_->Register(instance, this);
}
Error UpdateRegistration(const T& service) {
if (!service.IsValid()) {
return Error::Code::kParameterInvalid;
}
DnsSdInstance instance = conversion_(service);
return publisher_->UpdateRegistration(instance);
}
ErrorOr<int> DeregisterAll() {
return publisher_->DeregisterAll(service_name_);
}
protected:
// DnsSdPublisher::Client overrides.
//
// Embedders who care about the instance id with which the service was
// published may override this method.
void OnEndpointClaimed(
const DnsSdInstance& requested_instance,
const DnsSdInstanceEndpoint& claimed_endpoint) override {
OSP_DVLOG << "Instance ID '" << claimed_endpoint.instance_id()
<< "' claimed for requested ID '"
<< requested_instance.instance_id() << "'";
OnInstanceClaimed(requested_instance.instance_id());
}
virtual void OnInstanceClaimed(const std::string& requested_instance_id) {}
private:
ServiceInstanceConverter conversion_;
std::string service_name_;
DnsSdPublisher* const publisher_;
};
} // namespace discovery
} // namespace openscreen
#endif // DISCOVERY_PUBLIC_DNS_SD_SERVICE_PUBLISHER_H_