botaccount
/
limboai
mirror of https://github.com/limbonaut/limboai.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Rework HSM transitions bookkeeping 

Fixes a potential rare hash collision situation, and allows additional
attributes to be stored with the transition data in future.
This commit is contained in:
Serhii Snitsaruk 2024-07-21 13:28:13 +02:00
parent 0934e4e672
commit a7881a0eea
No known key found for this signature in database
GPG Key ID: A965EF8799FFEC2D
2 changed files with 49 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
hsm/limbo_hsm.cpp
View File

@ -104,19 +104,31 @@ void LimboHSM::add_transition(LimboState *p_from_state, LimboState *p_to_state,
ERR_FAIL_COND_MSG(p_to_state->get_parent() != this, "LimboHSM: Unable to add a transition to a state that is not an immediate child of mine.");
ERR_FAIL_COND_MSG(p_event == StringName(), "LimboHSM: Failed to add transition due to empty event string.");
uint64_t key = _get_transition_key(p_from_state, p_event);
transitions[key] = Object::cast_to<LimboState>(p_to_state);
TransitionKey key = Transition::make_key(p_from_state, p_event);
ERR_FAIL_COND_MSG(transitions.has(key), "LimboHSM: Unable to add another transition with the same event and origin.");
// Note: Explicit casting needed for GDExtension.
transitions[key] = { p_from_state != nullptr ? ObjectID(p_from_state->get_instance_id()) : ObjectID(), ObjectID(p_to_state->get_instance_id()), p_event };
}
void LimboHSM::remove_transition(LimboState *p_from_state, const StringName &p_event) {
ERR_FAIL_COND_MSG(p_from_state != nullptr && p_from_state->get_parent() != this, "LimboHSM: Unable to remove a transition from a state that is not an immediate child of mine.");
ERR_FAIL_COND_MSG(p_event == StringName(), "LimboHSM: Unable to remove a transition due to empty event string.");
uint64_t key = _get_transition_key(p_from_state, p_event);
TransitionKey key = Transition::make_key(p_from_state, p_event);
ERR_FAIL_COND_MSG(!transitions.has(key), "LimboHSM: Unable to remove a transition that does not exist.");
transitions.erase(key);
}
void LimboHSM::get_transition(LimboState *p_from_state, const StringName &p_event, Transition &r_transition) const {
ERR_FAIL_COND_MSG(p_from_state != nullptr && p_from_state->get_parent() != this, "LimboHSM: Unable to get a transition from a state that is not an immediate child of this HSM.");
ERR_FAIL_COND_MSG(p_event == StringName(), "LimboHSM: Unable to get a transition with an empty event string.");
TransitionKey key = Transition::make_key(p_from_state, p_event);
if (transitions.has(key)) {
r_transition = transitions[key];
}
}
LimboState *LimboHSM::get_leaf_state() const {
LimboHSM *hsm = const_cast<LimboHSM *>(this);
while (hsm->active_state != nullptr && hsm->active_state->is_class("LimboHSM")) {
@ -148,16 +160,18 @@ bool LimboHSM::_dispatch(const StringName &p_event, const Variant &p_cargo) {
}
if (!event_consumed && active_state) {
uint64_t key = _get_transition_key(active_state, p_event);
LimboState *to_state = nullptr;
if (transitions.has(key)) {
to_state = transitions[key];
Transition transition;
get_transition(active_state, p_event, transition);
if (transition.is_valid()) {
to_state = Object::cast_to<LimboState>(ObjectDB::get_instance(transition.to_state));
}
if (to_state == nullptr) {
// Get ANYSTATE transition.
key = _get_transition_key(nullptr, p_event);
if (transitions.has(key)) {
to_state = transitions[key];
get_transition(nullptr, p_event, transition);
if (transition.is_valid()) {
to_state = Object::cast_to<LimboState>(ObjectDB::get_instance(transition.to_state));
if (to_state == active_state) {
// Transitions to self are not allowed with ANYSTATE.
to_state = nullptr;

35
hsm/limbo_hsm.h
View File

@ -14,6 +14,16 @@
#include "limbo_state.h"
#define TransitionKey Pair<uint64_t, StringName>
struct TransitionKeyHasher {
static uint32_t hash(const TransitionKey &P) {
uint64_t h1 = HashMapHasherDefault::hash(P.first);
uint64_t h2 = HashMapHasherDefault::hash(P.second);
return hash_one_uint64((h1 << 32) | h2);
}
};
class LimboHSM : public LimboState {
GDCLASS(LimboHSM, LimboState);
@ -25,22 +35,28 @@ public:
};
private:
struct Transition {
ObjectID from_state;
ObjectID to_state;
StringName event;
inline bool is_valid() const { return to_state != ObjectID(); }
static _FORCE_INLINE_ TransitionKey make_key(LimboState *p_from_state, const StringName &p_event) {
return TransitionKey(
p_from_state != nullptr ? uint64_t(p_from_state->get_instance_id()) : 0,
p_event);
}
};
UpdateMode update_mode;
LimboState *initial_state;
LimboState *active_state;
LimboState *previous_active;
LimboState *next_active;
HashMap<uint64_t, LimboState *> transitions;
bool updating = false;
_FORCE_INLINE_ uint64_t _get_transition_key(LimboState *p_from_state, const StringName &p_event) {
uint64_t key = hash_djb2_one_64(Variant::OBJECT);
if (p_from_state != nullptr) {
key = hash_djb2_one_64(hash_one_uint64(hash_make_uint64_t(p_from_state)), key);
}
key = hash_djb2_one_64(p_event.hash(), key);
return key;
}
HashMap<TransitionKey, Transition, TransitionKeyHasher> transitions;
protected:
static void _bind_methods();
@ -75,6 +91,7 @@ public:
void add_transition(LimboState *p_from_state, LimboState *p_to_state, const StringName &p_event);
void remove_transition(LimboState *p_from_state, const StringName &p_event);
void get_transition(LimboState *p_from_state, const StringName &p_event, Transition &r_transition) const;
LimboState *anystate() const { return nullptr; }