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message_broker.h
/******************************************************************************
The MIT License(MIT)
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
Copyright(c) 2017 John Wellbelove
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions :
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
******************************************************************************/
#ifndef ETL_MESSAGE_BROKER_INCLUDED
#define ETL_MESSAGE_BROKER_INCLUDED
#include "platform.h"
#include "message.h"
#include "message_router.h"
#include "message_types.h"
#include "nullptr.h"
#include "span.h"
namespace etl
{
//***************************************************************************
//***************************************************************************
class message_broker : public etl::imessage_router
{
private:
//*******************************************
class subscription_node
{
friend class message_broker;
protected:
//*******************************
subscription_node()
: p_next(ETL_NULLPTR)
{
}
//*******************************
void set_next(subscription_node* sub)
{
p_next = sub;
}
//*******************************
subscription_node* get_next() const
{
return p_next;
}
//*******************************
void terminate()
{
set_next(ETL_NULLPTR);
}
//*******************************
void append(subscription_node* sub)
{
if (sub != ETL_NULLPTR)
{
sub->set_next(get_next());
}
set_next(sub);
}
subscription_node* p_next;
};
public:
typedef etl::span<const etl::message_id_t> message_id_span_t;
//*******************************************
class subscription : public subscription_node
{
public:
friend class message_broker;
//*******************************
subscription(etl::imessage_router& router_)
: p_router(&router_)
{
}
private:
//*******************************
virtual message_id_span_t message_id_list() const = 0;
//*******************************
etl::imessage_router* get_router() const
{
return p_router;
}
//*******************************
subscription* next_subscription() const
{
return static_cast<subscription*>(get_next());
}
etl::imessage_router* const p_router;
};
using etl::imessage_router::receive;
//*******************************************
//*******************************************
message_broker()
: imessage_router(etl::imessage_router::MESSAGE_BROKER)
, head()
{
}
//*******************************************
//*******************************************
message_broker(etl::imessage_router& successor_)
: imessage_router(etl::imessage_router::MESSAGE_BROKER, successor_)
, head()
{
}
//*******************************************
//*******************************************
message_broker(etl::message_router_id_t id_)
: imessage_router(id_)
, head()
{
ETL_ASSERT((id_ <= etl::imessage_router::MAX_MESSAGE_ROUTER) || (id_ == etl::imessage_router::MESSAGE_BROKER),
ETL_ERROR(etl::message_router_illegal_id));
}
//*******************************************
//*******************************************
message_broker(etl::message_router_id_t id_, etl::imessage_router& successor_)
: imessage_router(id_, successor_)
, head()
{
ETL_ASSERT((id_ <= etl::imessage_router::MAX_MESSAGE_ROUTER) || (id_ == etl::imessage_router::MESSAGE_BROKER),
ETL_ERROR(etl::message_router_illegal_id));
}
//*******************************************
//*******************************************
void subscribe(etl::message_broker::subscription& new_sub)
{
initialise_insertion_point(new_sub.get_router(), &new_sub);
}
//*******************************************
void unsubscribe(etl::imessage_router& router)
{
initialise_insertion_point(&router, ETL_NULLPTR);
}
//*******************************************
virtual void receive(const etl::imessage& msg) ETL_OVERRIDE
{
receive(etl::imessage_router::ALL_MESSAGE_ROUTERS, msg);
}
virtual void receive(etl::shared_message shared_msg) ETL_OVERRIDE
{
receive(etl::imessage_router::ALL_MESSAGE_ROUTERS, shared_msg);
}
//*******************************************
virtual void receive(etl::message_router_id_t destination_router_id, const etl::imessage& msg) ETL_OVERRIDE
{
const etl::message_id_t id = msg.get_message_id();
if (!empty())
{
// Scan the subscription lists.
subscription* sub = static_cast<subscription*>(head.get_next());
while (sub != ETL_NULLPTR)
{
message_id_span_t message_ids = sub->message_id_list();
message_id_span_t::iterator itr = etl::find(message_ids.begin(), message_ids.end(), id);
if (itr != message_ids.end())
{
etl::imessage_router* router = sub->get_router();
if (destination_router_id == etl::imessage_router::ALL_MESSAGE_ROUTERS || destination_router_id == router->get_message_router_id())
{
router->receive(msg);
}
}
sub = sub->next_subscription();
}
}
// Always pass the message on to the successor.
if (has_successor())
{
get_successor().receive(destination_router_id, msg);
}
}
//*******************************************
virtual void receive(etl::message_router_id_t destination_router_id, etl::shared_message shared_msg) ETL_OVERRIDE
{
const etl::message_id_t id = shared_msg.get_message().get_message_id();
if (!empty())
{
// Scan the subscription lists.
subscription* sub = static_cast<subscription*>(head.get_next());
while (sub != ETL_NULLPTR)
{
message_id_span_t message_ids = sub->message_id_list();
message_id_span_t::iterator itr = etl::find(message_ids.begin(), message_ids.end(), id);
if (itr != message_ids.end())
{
etl::imessage_router* router = sub->get_router();
if (destination_router_id == etl::imessage_router::ALL_MESSAGE_ROUTERS || destination_router_id == router->get_message_router_id())
{
router->receive(shared_msg);
}
}
sub = sub->next_subscription();
}
}
// Always pass the message on to a successor.
if (has_successor())
{
get_successor().receive(destination_router_id, shared_msg);
}
}
using imessage_router::accepts;
//*******************************************
//*******************************************
virtual bool accepts(etl::message_id_t id) const ETL_OVERRIDE
{
if (!empty())
{
// Scan the subscription lists.
subscription* sub = static_cast<subscription*>(head.get_next());
while (sub != ETL_NULLPTR)
{
message_id_span_t message_ids = sub->message_id_list();
message_id_span_t::iterator itr = etl::find(message_ids.begin(), message_ids.end(), id);
if (itr != message_ids.end())
{
etl::imessage_router* router = sub->get_router();
if (router->accepts(id))
{
return true;
}
}
sub = sub->next_subscription();
}
}
// Check any successor.
if (has_successor())
{
if (get_successor().accepts(id))
{
return true;
}
}
return false;
// return true;
}
//*******************************************
void clear()
{
head.terminate();
}
//********************************************
ETL_DEPRECATED
virtual bool is_null_router() const ETL_OVERRIDE
{
return false;
}
//********************************************
virtual bool is_producer() const ETL_OVERRIDE
{
return true;
}
//********************************************
virtual bool is_consumer() const ETL_OVERRIDE
{
return true;
}
//********************************************
bool empty() const
{
return head.get_next() == ETL_NULLPTR;
}
private:
//*******************************************
void initialise_insertion_point(const etl::imessage_router* p_router, etl::message_broker::subscription* p_new_sub)
{
const etl::imessage_router* p_target_router = p_router;
subscription_node* p_sub = head.get_next();
subscription_node* p_sub_previous = &head;
while (p_sub != ETL_NULLPTR)
{
// Do we already have a subscription for the router?
if (static_cast<subscription*>(p_sub)->get_router() == p_target_router)
{
// Then unlink it.
p_sub_previous->set_next(p_sub->get_next()); // Jump over the subscription.
p_sub->terminate(); // Terminate the unlinked subscription.
// We're done now.
break;
}
// Move on up the list.
p_sub = p_sub->get_next();
p_sub_previous = p_sub_previous->get_next();
}
if (p_new_sub != ETL_NULLPTR)
{
// Link in the new subscription.
p_sub_previous->append(p_new_sub);
}
}
subscription_node head;
};
} // namespace etl
#endif
etl::imessage_router
This is the base of all message routers.
Definition message_router.h:141
etl::imessage
Definition message.h:73
etl::message_broker::subscription
Definition message_broker.h:98
etl::message_broker::subscribe
void subscribe(etl::message_broker::subscription &new_sub)
Subscribe to the broker.
Definition message_broker.h:174
etl::message_broker::message_broker
message_broker()
Constructor.
Definition message_broker.h:134
etl::message_broker::message_broker
message_broker(etl::message_router_id_t id_)
Constructor.
Definition message_broker.h:152
etl::message_broker::accepts
virtual bool accepts(etl::message_id_t id) const ETL_OVERRIDE
Definition message_broker.h:276
etl::message_broker::message_broker
message_broker(etl::message_router_id_t id_, etl::imessage_router &successor_)
Constructor.
Definition message_broker.h:163
etl::message_broker::message_broker
message_broker(etl::imessage_router &successor_)
Constructor.
Definition message_broker.h:143
etl::message_router_illegal_id
Router id is out of the legal range.
Definition message_router.h:67
etl::span
Span - Fixed Extent.
Definition span.h:208
etl::span::begin
ETL_NODISCARD ETL_CONSTEXPR iterator begin() const ETL_NOEXCEPT
Returns an iterator to the beginning of the span.
Definition span.h:484
etl::span::end
ETL_NODISCARD ETL_CONSTEXPR iterator end() const ETL_NOEXCEPT
Returns an iterator to the end of the span.
Definition span.h:508
etl::successor< imessage_router >::has_successor
bool has_successor() const
Definition successor.h:184
etl::successor< imessage_router >::get_successor
successor_type & get_successor() const
Definition successor.h:174
ETL_ASSERT
#define ETL_ASSERT(b, e)
Definition error_handler.h:511
etl
Definition absolute.h:40
etl::message_id_t
uint_least8_t message_id_t
Allow alternative type for message id.
Definition message_types.h:40
nullptr.h
platform.h
span.h