iterable.hpp

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namespace flecs {
 
template <typename ... Components>
struct iter_iterable;
 
template <typename ... Components>
struct page_iterable;
 
template <typename ... Components>
struct worker_iterable;
 
template <typename ... Components>
struct iterable {
 
    template <typename Func>
    void each(Func&& func) const {
        ecs_iter_t it = this->get_iter(nullptr);
        ecs_iter_next_action_t next = this->next_action();
        while (next(&it)) {
            _::each_delegate<Func, Components...>(func).invoke(&it);
        }
    }
 
    template <typename Func>
    void run(Func&& func) const {
        ecs_iter_t it = this->get_iter(nullptr);
        _::run_delegate<Func>(func).invoke(&it);
    }
 
    template <typename Func>
    flecs::entity find(Func&& func) const {
        ecs_iter_t it = this->get_iter(nullptr);
        ecs_iter_next_action_t next = this->next_action();
 
        flecs::entity result;
        while (!result && next(&it)) {
            result = _::find_delegate<Func, Components...>(func).invoke(&it);
        }
 
        if (result) {
            ecs_iter_fini(&it);
        }
 
        return result;
    }
 
    iter_iterable<Components...> iter(flecs::world_t *world = nullptr) const;
 
    iter_iterable<Components...> iter(flecs::iter& iter) const;
 
    iter_iterable<Components...> iter(flecs::entity e) const;
 
    page_iterable<Components...> page(int32_t offset, int32_t limit);
 
    worker_iterable<Components...> worker(int32_t index, int32_t count);
 
    int32_t count() const {
        return this->iter().count();
    }
 
    bool is_true() const {
        return this->iter().is_true();
    }
 
    flecs::entity first() const {
        return this->iter().first();
    }
 
    iter_iterable<Components...> set_var(int var_id, flecs::entity_t value) const {
        return this->iter().set_var(var_id, value);
    }
 
    iter_iterable<Components...> set_var(const char *name, flecs::entity_t value) const {
        return this->iter().set_var(name, value);
    }
 
    iter_iterable<Components...> set_var(const char *name, flecs::table_t *value) const {
        return this->iter().set_var(name, value);
    }
 
    iter_iterable<Components...> set_var(const char *name, ecs_table_range_t value) const {
        return this->iter().set_var(name, value);
    }
 
    iter_iterable<Components...> set_var(const char *name, flecs::table_range value) const {
        return this->iter().set_var(name, value);
    }
 
    // Limit results to tables with specified group id (grouped queries only)
    iter_iterable<Components...> set_group(uint64_t group_id) const {
        return this->iter().set_group(group_id);
    }
 
    // Limit results to tables with specified group id (grouped queries only)
    template <typename Group>
    iter_iterable<Components...> set_group() const {
        return this->iter().template set_group<Group>();
    }
 
    virtual ~iterable() { }
protected:
    friend iter_iterable<Components...>;
    friend page_iterable<Components...>;
    friend worker_iterable<Components...>;
 
    virtual ecs_iter_t get_iter(flecs::world_t *stage) const = 0;
    virtual ecs_iter_next_action_t next_action() const = 0;
};
 
template <typename ... Components>
struct iter_iterable final : iterable<Components...> {
    template <typename Iterable>
    iter_iterable(Iterable *it, flecs::world_t *world) 
    {
        it_ = it->get_iter(world);
        next_ = it->next_action();
        next_each_ = it->next_action();
        ecs_assert(next_ != nullptr, ECS_INTERNAL_ERROR, NULL);
        ecs_assert(next_each_ != nullptr, ECS_INTERNAL_ERROR, NULL);
    }
 
    iter_iterable<Components...>& set_var(int var_id, flecs::entity_t value) {
        ecs_assert(var_id != -1, ECS_INVALID_PARAMETER, 0);
        ecs_iter_set_var(&it_, var_id, value);
        return *this;
    }
 
    iter_iterable<Components...>& set_var(const char *name, flecs::entity_t value) {
        int var_id = ecs_query_find_var(it_.query, name);
        ecs_assert(var_id != -1, ECS_INVALID_PARAMETER, name);
        ecs_iter_set_var(&it_, var_id, value);
        return *this;
    }
 
    iter_iterable<Components...>& set_var(const char *name, flecs::table_t *value) {
        int var_id = ecs_query_find_var(it_.query, name);
        ecs_assert(var_id != -1, ECS_INVALID_PARAMETER, name);
        ecs_iter_set_var_as_table(&it_, var_id, value);
        return *this;
    }
 
    iter_iterable<Components...>& set_var(const char *name, ecs_table_range_t value) {
        int var_id = ecs_query_find_var(it_.query, name);
        ecs_assert(var_id != -1, ECS_INVALID_PARAMETER, name);
        ecs_iter_set_var_as_range(&it_, var_id, &value);
        return *this;
    }
 
    iter_iterable<Components...>& set_var(const char *name, flecs::table_range value) {
        ecs_table_range_t range;
        range.table = value.get_table();
        range.offset = value.offset();
        range.count = value.count();
        return set_var(name, range);
    }
 
#   ifdef FLECS_JSON
#   include "../mixins/json/iterable.inl"
#   endif
 
    // Return total number of entities in result.
    int32_t count() {
        int32_t result = 0;
        while (next_each_(&it_)) {
            result += it_.count;
        }
        return result;
    }
 
    // Returns true if iterator yields at least once result.
    bool is_true() {
        bool result = next_each_(&it_);
        if (result) {
            ecs_iter_fini(&it_);
        }
        return result;
    }
 
    // Return first matching entity.
    flecs::entity first() {
        flecs::entity result;
        if (next_each_(&it_) && it_.count) {
            result = flecs::entity(it_.world, it_.entities[0]);
            ecs_iter_fini(&it_);
        }
        return result;
    }
 
    // Limit results to tables with specified group id (grouped queries only)
    iter_iterable<Components...>& set_group(uint64_t group_id) {
        ecs_iter_set_group(&it_, group_id);
        return *this;
    }
 
    // Limit results to tables with specified group id (grouped queries only)
    template <typename Group>
    iter_iterable<Components...>& set_group() {
        ecs_iter_set_group(&it_, _::type<Group>().id(it_.real_world));
        return *this;
    }
 
protected:
    ecs_iter_t get_iter(flecs::world_t *world) const override {
        if (world) {
            ecs_iter_t result = it_;
            result.world = world;
            return result;
        }
        return it_;
    }
 
    ecs_iter_next_action_t next_action() const override {
        return next_;
    }
 
private:
    ecs_iter_t it_;
    ecs_iter_next_action_t next_;
    ecs_iter_next_action_t next_each_;
};
 
template <typename ... Components>
iter_iterable<Components...> iterable<Components...>::iter(flecs::world_t *world) const
{
    return iter_iterable<Components...>(this, world);
}
 
template <typename ... Components>
iter_iterable<Components...> iterable<Components...>::iter(flecs::iter& it) const
{
    return iter_iterable<Components...>(this, it.world());
}
 
template <typename ... Components>
iter_iterable<Components...> iterable<Components...>::iter(flecs::entity e) const
{
    return iter_iterable<Components...>(this, e.world());
}
 
template <typename ... Components>
struct page_iterable final : iterable<Components...> {
    template <typename Iterable>
    page_iterable(int32_t offset, int32_t limit, Iterable *it) 
        : offset_(offset)
        , limit_(limit)
    {
        chain_it_ = it->get_iter(nullptr);
    }
 
protected:
    ecs_iter_t get_iter(flecs::world_t*) const {
        return ecs_page_iter(&chain_it_, offset_, limit_);
    }
 
    ecs_iter_next_action_t next_action() const {
        return ecs_page_next;
    }
 
private:
    ecs_iter_t chain_it_;
    int32_t offset_;
    int32_t limit_;
};
 
template <typename ... Components>
page_iterable<Components...> iterable<Components...>::page(
    int32_t offset, 
    int32_t limit) 
{
    return page_iterable<Components...>(offset, limit, this);
}
 
template <typename ... Components>
struct worker_iterable final : iterable<Components...> {
    worker_iterable(int32_t offset, int32_t limit, iterable<Components...> *it) 
        : offset_(offset)
        , limit_(limit)
    {
        chain_it_ = it->get_iter(nullptr);
    }
 
protected:
    ecs_iter_t get_iter(flecs::world_t*) const {
        return ecs_worker_iter(&chain_it_, offset_, limit_);
    }
 
    ecs_iter_next_action_t next_action() const {
        return ecs_worker_next;
    }
 
private:
    ecs_iter_t chain_it_;
    int32_t offset_;
    int32_t limit_;
};
 
template <typename ... Components>
worker_iterable<Components...> iterable<Components...>::worker(
    int32_t index, 
    int32_t count) 
{
    return worker_iterable<Components...>(index, count, this);
}
 
}