veloren/server/src/sys/loot.rs

use common::{comp::LootOwner, uid::UidAllocator};
use common_ecs::{Job, Origin, Phase, System};
use specs::{saveload::MarkerAllocator, Entities, Entity, Join, Read, WriteStorage};
use tracing::debug;

// This system manages loot that exists in the world
#[derive(Default)]
pub struct Sys;
impl<'a> System<'a> for Sys {
    type SystemData = (
        Entities<'a>,
        WriteStorage<'a, LootOwner>,
        Read<'a, UidAllocator>,
    );

    const NAME: &'static str = "loot";
    const ORIGIN: Origin = Origin::Server;
    const PHASE: Phase = Phase::Create;

    fn run(_job: &mut Job<Self>, (entities, mut loot_owners, uid_allocator): Self::SystemData) {
        // Find and remove expired loot ownership. Loot ownership is expired when either
        // the expiry time has passed, or the owner entity no longer exists
        let expired = (&entities, &loot_owners)
            .join()
            .filter(|(_, loot_owner)| {
                loot_owner.expired()
                    || uid_allocator
                        .retrieve_entity_internal(loot_owner.uid().into())
                        .map_or(true, |entity| !entities.is_alive(entity))
            })
            .map(|(entity, _)| entity)
            .collect::<Vec<Entity>>();

        if !&expired.is_empty() {
            debug!("Removing {} expired loot ownerships", expired.iter().len());
        }

        for entity in expired {
            loot_owners.remove(entity);
        }
    }
}