api.h

#pragma once
#include "gaia/config/config.h"
 
#include <cstdarg>
 
#include "gaia/core/span.h"
#include "gaia/ecs/command_buffer_fwd.h"
#include "gaia/ecs/id_fwd.h"
#include "gaia/ecs/query_fwd.h"
 
namespace gaia {
  namespace ecs {
    class World;
    class ComponentCache;
    class Archetype;
    struct ComponentCacheItem;
    struct EntityContainer;
    struct Entity;
 
    // Component API
 
    const ComponentCache& comp_cache(const World& world);
    ComponentCache& comp_cache_mut(World& world);
    template <typename T>
    const ComponentCacheItem& comp_cache_add(World& world);
 
    // Entity API
 
    const EntityContainer& fetch(const World& world, Entity entity);
    EntityContainer& fetch_mut(World& world, Entity entity);
 
    void del(World& world, Entity entity);
 
    Entity entity_from_id(const World& world, EntityId id);
    Entity id_entity(const World& world, Entity id);
    Entity pair_rel(const World& world, Entity pair);
    Entity pair_tgt(const World& world, Entity pair);
 
    bool valid(const World& world, Entity entity);
 
    bool is(const World& world, Entity entity, Entity baseEntity);
    bool is_base(const World& world, Entity entity);
 
    Archetype* archetype_from_entity(const World& world, Entity entity);
 
    util::str_view entity_name(const World& world, Entity entity);
    util::str_view entity_name(const World& world, EntityId entityId);
    Entity target(const World& world, Entity entity, Entity relation);
    void
    world_for_each_target(const World& world, Entity entity, Entity relation, void* ctx, void (*func)(void*, Entity));
    Entity world_pair_target_if_alive(const World& world, Entity pair);
    bool world_entity_enabled(const World& world, Entity entity);
    bool world_entity_enabled_hierarchy(const World& world, Entity entity, Entity relation);
    uint32_t world_enabled_hierarchy_version(const World& world);
    uint32_t world_archetype_delete_version(const World& world);
    uint32_t world_version(const World& world);
    uint32_t world_rel_version(const World& world, Entity relation);
    bool world_relation_is_non_fragmenting(const World& world, Entity relation);
    bool world_relation_is_hierarchy(const World& world, Entity relation);
    bool world_relation_is_fragmenting(const World& world, Entity relation);
    bool world_relation_is_fragmenting_hierarchy(const World& world, Entity relation);
    bool world_relation_supports_depth_order(const World& world, Entity relation);
    bool world_relation_depth_order_prunes_disabled_subtrees(const World& world, Entity relation);
    template <typename T>
    decltype(auto) world_query_entity_arg_by_id(World& world, Entity entity, Entity id);
 
    // Traversal API
 
    template <typename Func>
    void as_relations_trav(const World& world, Entity target, Func func);
    template <typename Func>
    bool as_relations_trav_if(const World& world, Entity target, Func func);
    template <typename Func>
    void as_targets_trav(const World& world, Entity relation, Func func);
    template <typename Func>
    bool as_targets_trav_if(const World& world, Entity relation, Func func);
    template <typename Func>
    void targets_trav(const World& world, Entity relation, Entity source, Func func);
    template <typename Func>
    bool targets_trav_if(const World& world, Entity relation, Entity source, Func func);
    const cnt::darray<Entity>& targets_trav_cache(const World& world, Entity relation, Entity source);
    template <typename Func>
    void sources(const World& world, Entity relation, Entity target, Func func);
    template <typename Func>
    void sources_if(const World& world, Entity relation, Entity target, Func func);
    const cnt::darray<Entity>& sources_bfs_trav_cache(const World& world, Entity relation, Entity rootTarget);
    template <typename Func>
    void sources_bfs(const World& world, Entity relation, Entity rootTarget, Func func);
    template <typename Func>
    bool sources_bfs_if(const World& world, Entity relation, Entity rootTarget, Func func);
    // Query API
 
    QuerySerBuffer& query_buffer(World& world, QueryId& serId);
    void query_buffer_reset(World& world, QueryId& serId);
 
    Entity expr_to_entity(const World& world, va_list& args, std::span<const char> exprRaw);
 
    GroupId group_by_func_default(const World& world, const Archetype& archetype, Entity groupBy);
 
    // Locking API
 
    void lock(World& world);
    void unlock(World& world);
    bool locked(const World& world);
 
#if GAIA_OBSERVERS_ENABLED
    // Deferred observer-notification API
    //
    // Observer dispatch mutates world-owned state and runs user callbacks, so it cannot happen
    // on a worker thread. Regions whose writes may run in parallel record notifications instead
    // and let the coordinator deliver them after the region joins.
 
    void world_defer_on_set_begin(World& world, uint32_t slotCount);
    void world_defer_on_set_end(World& world);
#endif
 
    // Deferred sorted-query invalidation API
    //
    // Sorted-query invalidation flips a shared `SortEntities` dirty bit on every sorted query
    // keyed by the written component. That shared flag is not safe to touch from a worker
    // thread, so regions whose writes may run in parallel record which component entities were
    // written and the coordinator applies the invalidation once the region joins. Work items
    // identify themselves with the shared deferral slot below, which the observer (`OnSet`)
    // channel uses as well.
 
    inline static constexpr uint32_t BadDeferSlot = (uint32_t)-1;
 
    void world_defer_sort_inv_begin(World& world, uint32_t slotCount);
    void world_defer_sort_inv_end(World& world);
 
    void world_defer_parallel_begin(World& world, uint32_t itemCount);
    void world_defer_parallel_end(World& world);
 
    GAIA_NODISCARD inline uint32_t& defer_slot_ref() {
      static thread_local uint32_t s_slot = BadDeferSlot;
      return s_slot;
    }
 
    GAIA_NODISCARD inline uint32_t defer_slot() {
      return defer_slot_ref();
    }
 
    class DeferSlotScope final {
      uint32_t m_prev;
 
    public:
      explicit DeferSlotScope(uint32_t slot): m_prev(defer_slot_ref()) {
        defer_slot_ref() = slot;
      }
      ~DeferSlotScope() {
        defer_slot_ref() = m_prev;
      }
 
      DeferSlotScope(DeferSlotScope&&) = delete;
      DeferSlotScope(const DeferSlotScope&) = delete;
      DeferSlotScope& operator=(DeferSlotScope&&) = delete;
      DeferSlotScope& operator=(const DeferSlotScope&) = delete;
    };
 
    // CommandBuffer API
 
    CommandBufferST& cmd_buffer_st_get(World& world);
    CommandBufferMT& cmd_buffer_mt_get(World& world);
    void commit_cmd_buffer_st(World& world);
    void commit_cmd_buffer_mt(World& world);
  } // namespace ecs
} // namespace gaia