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/******************************************************************************
* ____ _ _____ *
* / ___| / \ | ___| C++ *
* | | / _ \ | |_ Actor *
* | |___ / ___ \| _| Framework *
* \____/_/ \_|_| *
* *
* Copyright 2011-2018 Dominik Charousset *
* *
* Distributed under the terms and conditions of the BSD 3-Clause License or *
* (at your option) under the terms and conditions of the Boost Software *
* License 1.0. See accompanying files LICENSE and LICENSE_ALTERNATIVE. *
* *
* If you did not receive a copy of the license files, see *
* http://opensource.org/licenses/BSD-3-Clause and *
* http://www.boost.org/LICENSE_1_0.txt. *
******************************************************************************/
#pragma once
#include <utility>
#include <vector>
#include <cstdint>
#include "caf/actor_addr.hpp"
#include "caf/actor_control_block.hpp"
#include "caf/atom.hpp"
#include "caf/message.hpp"
#include "caf/stream_priority.hpp"
#include "caf/stream_slot.hpp"
#include "caf/timespan.hpp"
#include "caf/variant.hpp"
#include "caf/tag/boxing_type.hpp"
#include "caf/detail/type_list.hpp"
namespace caf {
/// Stream messages that flow upstream, i.e., acks and drop messages.
struct upstream_msg : tag::boxing_type {
// -- nested types -----------------------------------------------------------
/// Acknowledges a previous `open` message and finalizes a stream handshake.
/// Also signalizes initial demand.
struct ack_open {
/// Allows the testing DSL to unbox this type automagically.
using outer_type = upstream_msg;
/// Allows actors to participate in a stream instead of the actor
/// originally receiving the `open` message. No effect when set to
/// `nullptr`. This mechanism enables pipeline definitions consisting of
/// proxy actors that are replaced with actual actors on demand.
actor_addr rebind_from;
/// Points to sender_, but with a strong reference.
strong_actor_ptr rebind_to;
/// Grants credit to the source.
int32_t initial_demand;
/// Desired size of individual batches.
int32_t desired_batch_size;
};
/// Cumulatively acknowledges received batches and signalizes new demand from
/// a sink to its source.
struct ack_batch {
/// Allows the testing DSL to unbox this type automagically.
using outer_type = upstream_msg;
/// Newly available credit.
int32_t new_capacity;
/// Desired size of individual batches for the next cycle.
int32_t desired_batch_size;
/// Cumulative ack ID.
int64_t acknowledged_id;
/// Maximum capacity on this path. Stages can consider this metric for
/// downstream actors when calculating their own maximum capactiy.
int32_t max_capacity;
};
/// Asks the source to discard any remaining credit and close this path
/// after receiving an ACK for the last batch.
struct drop {
/// Allows the testing DSL to unbox this type automagically.
using outer_type = upstream_msg;
};
/// Propagates a fatal error from sinks to sources.
struct forced_drop {
/// Allows the testing DSL to unbox this type automagically.
using outer_type = upstream_msg;
/// Reason for shutting down the stream.
error reason;
};
// -- member types -----------------------------------------------------------
/// Lists all possible options for the payload.
using alternatives =
detail::type_list<ack_open, ack_batch, drop, forced_drop>;
/// Stores one of `alternatives`.
using content_type = variant<ack_open, ack_batch, drop, forced_drop>;
// -- constructors, destructors, and assignment operators --------------------
template <class T>
upstream_msg(stream_slots id, actor_addr addr, T&& x)
: slots(id),
sender(std::move(addr)),
content(std::forward<T>(x)) {
// nop
}
upstream_msg() = default;
upstream_msg(upstream_msg&&) = default;
upstream_msg(const upstream_msg&) = default;
upstream_msg& operator=(upstream_msg&&) = default;
upstream_msg& operator=(const upstream_msg&) = default;
// -- member variables -------------------------------------------------------
/// Stream slots of sender and receiver.
stream_slots slots;
/// Address of the sender. Identifies the up- or downstream actor sending
/// this message. Note that abort messages can get send after `sender`
/// already terminated. Hence, `current_sender()` can be `nullptr`, because
/// no strong pointers can be formed any more and receiver would receive an
/// anonymous message.
actor_addr sender;
/// Palyoad of the message.
content_type content;
};
/// Allows the testing DSL to unbox `upstream_msg` automagically.
template <class T>
const T& get(const upstream_msg& x) {
return get<T>(x.content);
}
/// Allows the testing DSL to check whether `upstream_msg` holds a `T`.
template <class T>
bool is(const upstream_msg& x) {
return holds_alternative<T>(x.content);
}
/// @relates upstream_msg
template <class T, class... Ts>
detail::enable_if_tt<detail::tl_contains<upstream_msg::alternatives, T>,
upstream_msg>
make(stream_slots slots, actor_addr addr, Ts&&... xs) {
return {slots, std::move(addr), T{std::forward<Ts>(xs)...}};
}
/// @relates upstream_msg::ack_open
template <class Inspector>
typename Inspector::result_type inspect(Inspector& f,
upstream_msg::ack_open& x) {
return f(meta::type_name("ack_open"), x.rebind_from, x.rebind_to,
x.initial_demand, x.desired_batch_size);
}
/// @relates upstream_msg::ack_batch
template <class Inspector>
typename Inspector::result_type inspect(Inspector& f,
upstream_msg::ack_batch& x) {
return f(meta::type_name("ack_batch"), x.new_capacity, x.desired_batch_size,
x.acknowledged_id);
}
/// @relates upstream_msg::drop
template <class Inspector>
typename Inspector::result_type inspect(Inspector& f, upstream_msg::drop&) {
return f(meta::type_name("drop"));
}
/// @relates upstream_msg::forced_drop
template <class Inspector>
typename Inspector::result_type inspect(Inspector& f,
upstream_msg::forced_drop& x) {
return f(meta::type_name("forced_drop"), x.reason);
}
/// @relates upstream_msg
template <class Inspector>
typename Inspector::result_type inspect(Inspector& f, upstream_msg& x) {
return f(meta::type_name("upstream_msg"), x.slots, x.sender, x.content);
}
} // namespace caf
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