diff --git a/Core/include/Acts/Utilities/FiniteStateMachine.hpp b/Core/include/Acts/Utilities/FiniteStateMachine.hpp
index c8fdcd66a74d94b72582c2a01f0a55835774869f..3ebaa2da7bbad6a177bcfb7d97b8a15dd52293dc 100644
--- a/Core/include/Acts/Utilities/FiniteStateMachine.hpp
+++ b/Core/include/Acts/Utilities/FiniteStateMachine.hpp
@@ -8,6 +8,8 @@
#pragma once
+#include "Acts/Utilities/TypeTraits.hpp"
+
#include <optional>
#include <string_view>
#include <variant>
@@ -37,21 +39,37 @@ class FiniteStateMachine {
const StateVariant& getState() const noexcept { return m_state; }
StateVariant& getState() noexcept { return m_state; }
+ private:
+ template <typename T, typename S, typename... Args>
+ using on_exit_t = decltype(
+ std::declval<T>().on_exit(std::declval<S&>(), std::declval<Args>()...));
- template <typename... Args>
- void setState(StateVariant state, Args&&... args) {
+ template <typename T, typename S, typename... Args>
+ using on_enter_t = decltype(
+ std::declval<T>().on_enter(std::declval<S&>(), std::declval<Args>()...));
+
+ public:
+ template <typename State, typename... Args>
+ void setState(State state, Args&&... args) {
Derived& child = static_cast<Derived&>(*this);
// call on exit function
- std::visit([&](auto& s) { child.on_exit(s, std::forward<Args>(args)...); },
- m_state);
+ std::visit(
+ [&](auto& s) {
+ using state_type = decltype(s);
+ if constexpr (concept ::exists<on_exit_t, Derived, state_type,
+ Args...>) {
+ child.on_exit(s, std::forward<Args>(args)...);
+ }
+ },
+ m_state);
- // no change state
m_state = std::move(state);
- // call on enter function
- std::visit([&](auto& s) { child.on_enter(s, std::forward<Args>(args)...); },
- m_state);
+ // call on enter function, the type is known from the template argument.
+ if constexpr (concept ::exists<on_enter_t, Derived, State, Args...>) {
+ child.on_enter(std::get<State>(m_state), std::forward<Args>(args)...);
+ }
}
template <typename S>
@@ -64,21 +82,57 @@ class FiniteStateMachine {
bool terminated() const noexcept { return is(Terminated{}); }
+ private:
+ template <typename T, typename S, typename E, typename... Args>
+ using on_event_t = decltype(std::declval<T>().on_event(
+ std::declval<S&>(), std::declval<E&>(), std::declval<Args>()...));
+
+ template <typename T, typename... Args>
+ using on_process_t =
+ decltype(std::declval<T>().on_process(std::declval<Args>()...));
+
+ protected:
template <typename Event, typename... Args>
event_return process_event(Event&& event, Args&&... args) {
Derived& child = static_cast<Derived&>(*this);
- child.log(event);
+
+ if constexpr (concept ::exists<on_process_t, Derived, Event>) {
+ child.on_process(event);
+ }
+
auto new_state = std::visit(
[&](auto& s) -> std::optional<StateVariant> {
- auto s2 = child.on_event(s, std::forward<Event>(event),
- std::forward<Args>(args)...);
-
- if (s2) {
- std::visit([&](auto& s2_) { child.log(s, event, s2_); }, *s2);
+ using state_type = decltype(s);
+
+ if constexpr (concept ::exists<on_event_t, Derived, state_type, Event,
+ Args...>) {
+ auto s2 = child.on_event(s, std::forward<Event>(event),
+ std::forward<Args>(args)...);
+
+ if (s2) {
+ std::visit(
+ [&](auto& s2_) {
+ if constexpr (concept ::exists<on_process_t, Derived,
+ state_type, Event,
+ decltype(s2_)>) {
+ child.on_process(s, event, s2_);
+ }
+ },
+ *s2);
+ } else {
+ if constexpr (concept ::exists<on_process_t, Derived, state_type,
+ Event>) {
+ child.on_process(s, event);
+ }
+ }
+ return std::move(s2);
} else {
- child.log(s, event);
+ if constexpr (concept ::exists<on_process_t, Derived, state_type,
+ Event, Terminated>) {
+ child.on_process(s, event, Terminated{});
+ }
+ return Terminated{};
}
- return std::move(s2);
},
m_state);
return std::move(new_state);
@@ -88,7 +142,9 @@ class FiniteStateMachine {
void dispatch(Event&& event, Args&&... args) {
auto new_state = process_event(std::forward<Event>(event), args...);
if (new_state) {
- setState(std::move(*new_state), std::forward<Args>(args)...);
+ std::visit(
+ [&](auto& s) { setState(std::move(s), std::forward<Args>(args)...); },
+ *new_state);
}
}
diff --git a/Tests/Core/Utilities/FiniteStateMachineTests.cpp b/Tests/Core/Utilities/FiniteStateMachineTests.cpp
index 4b9dd5eb0092476884bbf7a1b2d3736e8c4ddc1c..a745f9168233692743731390de59841b815cfed9 100644
--- a/Tests/Core/Utilities/FiniteStateMachineTests.cpp
+++ b/Tests/Core/Utilities/FiniteStateMachineTests.cpp
@@ -69,20 +69,6 @@ struct fsm : FiniteStateMachine<fsm, states::Disconnected, states::Connecting,
event_return on_event(const states::Connected&, const events::Disconnect&) {
return states::Disconnected{};
}
-
- template <typename State, typename Event>
- event_return on_event(const State&, const Event&) const {
- return Terminated{};
- }
-
- template <typename State, typename... Args>
- void on_enter(const State&, Args&&...) {}
-
- template <typename State, typename... Args>
- void on_exit(const State&, Args&&...) {}
-
- template <typename... Args>
- void log(Args&&...) {}
};
BOOST_AUTO_TEST_SUITE(Utilities)
@@ -107,7 +93,7 @@ BOOST_AUTO_TEST_CASE(Transitions) {
BOOST_CHECK(sm.is(states::Disconnected{}));
}
-BOOST_AUTO_TEST_CASE(Terminted) {
+BOOST_AUTO_TEST_CASE(Terminated) {
fsm sm{};
BOOST_CHECK(sm.is(states::Disconnected{}));
@@ -139,14 +125,6 @@ struct fsm2
void on_enter(const Terminated&, Args&&...) {
throw std::runtime_error("FSM terminated!");
}
-
- template <typename State, typename... Args>
- void on_enter(const State&, Args&&...) {}
-
- template <typename State, typename... Args>
- void on_exit(const State&, Args&&...) {}
- template <typename... Args>
- void log(Args&&...) {}
};
BOOST_AUTO_TEST_CASE(Arguments) {
@@ -187,9 +165,11 @@ struct E3 {};
struct fsm3 : FiniteStateMachine<fsm3, S1, S2, S3> {
bool on_exit_called = false;
bool on_enter_called = false;
+ bool on_process_called = false;
void reset() {
on_exit_called = false;
on_enter_called = false;
+ on_process_called = false;
}
// S1 + E1 = S2
@@ -210,13 +190,6 @@ struct fsm3 : FiniteStateMachine<fsm3, S1, S2, S3> {
// external transition
event_return on_event(const S2&, const E3&) { return S3{}; }
- // catchers
-
- template <typename State, typename Event, typename... Args>
- event_return on_event(const State&, const Event&, Args&&...) const {
- return Terminated{};
- }
-
template <typename State, typename... Args>
void on_enter(const State&, Args&&...) {
on_enter_called = true;
@@ -226,8 +199,11 @@ struct fsm3 : FiniteStateMachine<fsm3, S1, S2, S3> {
void on_exit(const State&, Args&&...) {
on_exit_called = true;
}
+
template <typename... Args>
- void log(Args&&...) {}
+ void on_process(Args&&...) {
+ on_process_called = true;
+ }
};
BOOST_AUTO_TEST_CASE(InternalTransitions) {
@@ -238,6 +214,7 @@ BOOST_AUTO_TEST_CASE(InternalTransitions) {
BOOST_CHECK(sm.is(S2{}));
BOOST_CHECK(sm.on_exit_called);
BOOST_CHECK(sm.on_enter_called);
+ BOOST_CHECK(sm.on_process_called);
sm.reset();
@@ -247,6 +224,7 @@ BOOST_AUTO_TEST_CASE(InternalTransitions) {
// on_enter / exit should have been called
BOOST_CHECK(sm.on_exit_called);
BOOST_CHECK(sm.on_enter_called);
+ BOOST_CHECK(sm.on_process_called);
sm.reset();
sm.dispatch(E2{});
@@ -255,6 +233,7 @@ BOOST_AUTO_TEST_CASE(InternalTransitions) {
// on_enter / exit should NOT have been called
BOOST_CHECK(!sm.on_exit_called);
BOOST_CHECK(!sm.on_enter_called);
+ BOOST_CHECK(sm.on_process_called);
sm.reset();
sm.dispatch(E3{});
@@ -262,7 +241,19 @@ BOOST_AUTO_TEST_CASE(InternalTransitions) {
// on_enter / exit should have been called
BOOST_CHECK(sm.on_exit_called);
BOOST_CHECK(sm.on_enter_called);
+ BOOST_CHECK(sm.on_process_called);
+
+ sm.setState(S1{});
sm.reset();
+ BOOST_CHECK(sm.is(S1{}));
+ // dispatch invalid event
+ sm.dispatch(E3{});
+ // should be terminated now
+ BOOST_CHECK(sm.terminated());
+ // hooks should have fired
+ BOOST_CHECK(sm.on_exit_called);
+ BOOST_CHECK(sm.on_enter_called);
+ BOOST_CHECK(sm.on_process_called);
}
BOOST_AUTO_TEST_SUITE_END()