【Lua实战】闭包计数器：无侵入的调用统计方案

---函数包装：调用计数与耗时采样
local counters = {}

local function countWrap(name, fn)
    counters[name] = { calls = 0, cost = 0 }
    return function(...)
        local t0 = os.clock()
        local r = { fn(...) }
        counters[name].calls = counters[name].calls + 1
        counters[name].cost = counters[name].cost + (os.clock() - t0)
        return unpack(r)
    end
end

---包装目标函数：原变量直接替换
local rawSend = sendmsg
sendmsg = function(actor, t, m)
    return countWrap("sendmsg", rawSend)(actor, t, m)
end

---每分钟输出调用榜
setontimerex(75, 60)
function Counter.report()
    local list = {}
    for name, c in pairs(counters) do
        list[#list + 1] = {
            name = name, calls = c.calls,
            avg = c.calls > 0 and c.cost / c.calls or 0,
        }
    end
    table.sort(list, function(a, b) return a.calls > b.calls end)
    for i = 1, math.min(5, #list) do
        Ops.log(("%s x%d avg %.3fms"):format(
            list[i].name, list[i].calls,
            list[i].avg * 1000))
    end
    for _, c in pairs(counters) do c.calls = 0; c.cost = 0 end
end