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// Copyright 2019 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_MDNS_MDNS_QUERIER_H_
#define DISCOVERY_MDNS_MDNS_QUERIER_H_
#include <map>
#include "discovery/mdns/mdns_record_changed_callback.h"
#include "discovery/mdns/mdns_records.h"
#include "platform/api/task_runner.h"
namespace openscreen {
namespace discovery {
class MdnsRandom;
class MdnsReceiver;
class MdnsSender;
class MdnsQuestionTracker;
class MdnsRecordTracker;
class MdnsQuerier {
public:
using ClockNowFunctionPtr = openscreen::platform::ClockNowFunctionPtr;
using TaskRunner = openscreen::platform::TaskRunner;
MdnsQuerier(MdnsSender* sender,
MdnsReceiver* receiver,
TaskRunner* task_runner,
ClockNowFunctionPtr now_function,
MdnsRandom* random_delay);
MdnsQuerier(const MdnsQuerier& other) = delete;
MdnsQuerier(MdnsQuerier&& other) noexcept = delete;
MdnsQuerier& operator=(const MdnsQuerier& other) = delete;
MdnsQuerier& operator=(MdnsQuerier&& other) noexcept = delete;
~MdnsQuerier();
// Starts an mDNS query with the given name, DNS type, and DNS class. Updated
// records are passed to |callback|. The caller must ensure |callback|
// remains alive while it is registered with a query.
void StartQuery(const DomainName& name,
DnsType dns_type,
DnsClass dns_class,
MdnsRecordChangedCallback* callback);
// Stops an mDNS query with the given name, DNS type, and DNS class.
// |callback| must be the same callback pointer that was previously passed to
// StartQuery.
void StopQuery(const DomainName& name,
DnsType dns_type,
DnsClass dns_class,
MdnsRecordChangedCallback* callback);
private:
struct CallbackInfo {
MdnsRecordChangedCallback* const callback;
const DnsType dns_type;
const DnsClass dns_class;
};
// Callback passed to MdnsReceiver
void OnMessageReceived(const MdnsMessage& message);
// Callback passed to owned MdnsRecordTrackers
void OnRecordExpired(const MdnsRecord& record);
void ProcessRecords(const std::vector<MdnsRecord>& records);
void ProcessSharedRecord(const MdnsRecord& record);
void ProcessUniqueRecord(const MdnsRecord& record);
void ProcessCallbacks(const MdnsRecord& record, RecordChangedEvent event);
void AddQuestion(const MdnsQuestion& question);
void AddRecord(const MdnsRecord& record);
MdnsSender* const sender_;
MdnsReceiver* const receiver_;
TaskRunner* const task_runner_;
const ClockNowFunctionPtr now_function_;
MdnsRandom* const random_delay_;
// A collection of active question trackers, each is uniquely identified by
// domain name, DNS record type, and DNS record class. Multimap key is domain
// name only to allow easy support for wildcard processing for DNS record type
// and class. MdnsQuestionTracker instances are stored as unique_ptr so they
// are not moved around in memory when the collection is modified. This allows
// passing a pointer to MdnsQuestionTracker to a task running on the
// TaskRunner.
std::multimap<DomainName, std::unique_ptr<MdnsQuestionTracker>> questions_;
// A collection of active known record trackers, each is identified by domain
// name, DNS record type, and DNS record class. Multimap key is domain name
// only to allow easy support for wildcard processing for DNS record type and
// class and allow storing shared records that differ only in RDATA.
// MdnsRecordTracker instances are stored as unique_ptr so they are not moved
// around in memory when the collection is modified. This allows passing a
// pointer to MdnsQuestionTracker to a task running on the TaskRunner.
std::multimap<DomainName, std::unique_ptr<MdnsRecordTracker>> records_;
// A collection of callbacks passed to StartQuery method. Each is identified
// by domain name, DNS record type, and DNS record class, but there can be
// more than one callback for a particular query. Multimap key is domain name
// only to allow easy matching of records against callbacks that have wildcard
// DNS class and/or DNS type.
std::multimap<DomainName, CallbackInfo> callbacks_;
};
} // namespace discovery
} // namespace openscreen
#endif // DISCOVERY_MDNS_MDNS_QUERIER_H_
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