【高级技巧】扫描顺清理：惰性到期的顺路回收

local buffs = {}
local function lazyGetBuff(actorName, buffId)
    actor = getplayerbyname(actorName)
    local b = buffs[actorName] and buffs[actorName][buffId]
    if b == nil then
        return nil
    end
    if os.time() >= b.expire then
        buffs[actorName][buffId] = nil
        sendmsg(actor, 1, buffId .. " 效果已到期。")
        return nil
    end
    return b
end
local function sweepBuffs()
    local now = os.time()
    local cleared = 0
    for name, set in pairs(buffs) do
        for id, b in pairs(set) do
            if now >= b.expire then
                set[id] = nil
                cleared = cleared + 1
            end
        end
        if next(set) == nil then
            buffs[name] = nil
        end
    end
    return cleared
end

setontimerex(78, 60000)
local function ontimerex78()
    local n = sweepBuffs()
    if n > 0 then
        sendmsg(nil, 1, "顺路清理过期增益 " .. n .. " 条")
    end
end