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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include "iprotocol.h"
#include <map>
#include <atomic>
#include <mutex>
namespace mbus {
/**
* Implements a thread-safe repository for protocols and their routing policies. This manages an internal cache of
* routing policies so that similarly referenced policy directives share the same instance of a policy.
* However for speed the protocols themselves must be kept alive on the outside when returned from
* putProtocol. There is only room for a limited number of protocols.
*/
class ProtocolRepository {
private:
using ProtocolMap = std::map<string, IProtocol::SP>;
using RoutingPolicyCache = std::map<string, IRoutingPolicy::SP>;
std::mutex _lock; // Only guards the cache,
// not the protocols as they are set up during messagebus construction.
static constexpr size_t MAX_PROTOCOLS = 16;
std::pair<string, std::atomic<IProtocol *>> _protocols[MAX_PROTOCOLS];
std::atomic<size_t> _numProtocols;
ProtocolMap _activeProtocols;
RoutingPolicyCache _routingPolicyCache;
public:
ProtocolRepository(const ProtocolRepository &) = delete;
ProtocolRepository & operator = (const ProtocolRepository &) = delete;
ProtocolRepository();
~ProtocolRepository();
/**
* Registers a protocol with this repository. This will overwrite any protocol that was registered earlier
* that has the same name. If this method detects a protocol replacement, it will clear its internal
* routing policy cache. You must keep the old protocol returned until there can be no usages of the references
* acquired from getProtocol.
*
* Must not be called concurrently by multiple threads.
*
* @param protocol The protocol to register.
* @return The previous protocol registered under this name.
*/
IProtocol::SP putProtocol(const IProtocol::SP & protocol);
/**
* Returns the protocol whose name matches the given argument. This method will return null if no such
* protocol has been registered.
*
* @param name The name of the protocol to return.
* @return The protocol registered, or null.
*/
IProtocol * getProtocol(const string &name);
/**
* Creates and returns a routing policy that matches the given arguments. If a routing policy has been
* created previously using the exact same parameters, this method will returned that cached instance
* instead of creating another. Not that when you replace a protocol using {@link #putProtocol(Protocol)}
* the policy cache is cleared.
*
* @param protocolName The name of the protocol whose routing policy to create.
* @param policyName The name of the routing policy to create.
* @param policyParam The parameter to pass to the routing policy constructor.
* @return The created routing policy.
*/
IRoutingPolicy::SP getRoutingPolicy(const string &protocolName,
const string &policyName,
const string &policyParam);
/**
* Clears the internal cache of routing policies.
*/
void clearPolicyCache();
};
}
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