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// Copyright 2014 The Chromium OS 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 PEERD_AVAHI_CLIENT_H_
#define PEERD_AVAHI_CLIENT_H_
#include <string>
#include <vector>
#include <base/callback.h>
#include <base/memory/ref_counted.h>
#include <base/memory/weak_ptr.h>
#include <dbus/bus.h>
#include <dbus/message.h>
#include "peerd/avahi_service_discoverer.h"
#include "peerd/avahi_service_publisher.h"
#include "peerd/typedefs.h"
namespace dbus {
class ObjectProxy;
} // namespace dbus
namespace peerd {
class AvahiServicePublisher;
class PeerManagerInterface;
class ServicePublisherInterface;
// DBus client managing our interface to the Avahi daemon.
class AvahiClient {
public:
using OnAvahiRestartCallback = base::Closure;
AvahiClient(const scoped_refptr<dbus::Bus>& bus,
PeerManagerInterface* peer_manager);
virtual ~AvahiClient();
virtual void RegisterAsync(const CompletionAction& cb);
// Register interest in Avahi daemon restarts. For instance, Avahi
// restarts should trigger us to re-register all exposed services,
// since the hostname for our local host may have changed.
// If Avahi is up right now, we'll call this callback immediately.
// Registered callbacks are persistent for the life of AvahiClient.
virtual void RegisterOnAvahiRestartCallback(const OnAvahiRestartCallback& cb);
// Get an instance of ServicePublisherInterface that knows how to advertise
// services on Avahi. From time to time, this pointer will transparently
// become invalid as the remote daemon signals that bad things have happened.
// When we come back from these states, we'll call all
// OnAvahiRestartCallbacks that we have. At that point, grab a new publisher
// and repeat.
virtual base::WeakPtr<ServicePublisherInterface> GetPublisher(
const std::string& uuid);
virtual void StartMonitoring();
virtual void StopMonitoring();
virtual void AttemptToUseMDnsPrefix(const std::string& mdns_prefix);
// Transform a service_id to a mDNS compatible service type.
static std::string GetServiceType(const std::string& service_id);
// Transform a mDNS compatible service type to a service id.
static std::string GetServiceId(const std::string& service_type);
private:
// Watch for changes in Avahi server state.
void OnServerStateChanged(int32_t state, const std::string& error);
// ObjectProxy forces us to register a one off "ServiceAvailable"
// callback for startup, then register to listen to service owner changes
// in steady state.
void OnServiceOwnerChanged(const std::string& old_owner,
const std::string& new_owner);
void OnServiceAvailable(bool avahi_is_on_dbus);
// Logic to react to Avahi server state changes.
void HandleServerStateChange(int32_t state);
// Logic to react to failure or success to start service discovery.
void HandleDiscoveryStartupResult(bool success);
// When we encounter problems publishing mDNS records, it should be
// related to name collisions on the local subnet. We'll just pick
// a new unique prefix for our records and try again.
void HandlePublishingFailure();
scoped_refptr<dbus::Bus> bus_;
PeerManagerInterface* peer_manager_; // Outlives this.
dbus::ObjectProxy* server_{nullptr};
std::vector<OnAvahiRestartCallback> avahi_ready_callbacks_;
bool avahi_is_up_{false};
std::unique_ptr<AvahiServicePublisher> publisher_{nullptr};
std::unique_ptr<AvahiServiceDiscoverer> discoverer_{nullptr};
bool should_discover_{false};
std::string next_mdns_prefix_;
// Must be last member to invalidate pointers before actual destruction.
base::WeakPtrFactory<AvahiClient> weak_ptr_factory_{this};
friend class AvahiClientTest;
DISALLOW_COPY_AND_ASSIGN(AvahiClient);
};
} // namespace peerd
#endif // PEERD_AVAHI_CLIENT_H_
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