Clink prompt filetring profiler

clink.lua

function clink.filter_prompt(prompt)
    local function add_ansi_codes(p)
        local c = tonumber(clink.get_setting_int("prompt_colour"))
        if c < 0 then
            return p
        end

        c = c % 16

        --[[
            <4              >=4             %2
            0 0  0 Black    4 1 -3 Blue     0
            1 4  3 Red      5 5  0 Magenta  1
            2 2  0 Green    6 3 -3 Cyan     0
            3 6  3 Yellow   7 7  0 Gray     1
        --]]

        -- Convert from cmd.exe colour indices to ANSI ones.
        local colour_id = c % 8
        if (colour_id % 2) == 1 then
            if colour_id < 4 then
                c = c + 3
            end
        elseif colour_id >= 4 then
            c = c - 3
        end

        -- Clamp
        if c > 15 then
            c = 15
        end

        -- Build ANSI code
        local code = "\x1b[0;"
        if c > 7 then
            c = c - 8
            code = code.."1;"
        end
        code = code..(c + 30).."m"

        return code..p.."\x1b[0m"
    end

    local calls, total, this = {}, {}, {}

    local function profile_hook(event)
        local i = debug.getinfo(2, "Sln")
        if i.what ~= 'Lua' then return end
        local func = (i.name or "")..":"..(i.source..' : '..i.linedefined)
        if event == 'call' then
            this[func] = os.clock()
        else
            if this[func] then
                local time = os.clock() - this[func]
                total[func] = (total[func] or 0) + time
                calls[func] = (calls[func] or 0) + 1
            end
        end
    end

    local function unset_profile_hook()
        for f,time in pairs(total) do
            print(("Function %s took %.3f seconds after %d calls"):format(f, time, calls[f]))
        end
        debug.sethook()
    end

    clink.prompt.value = prompt

    debug.sethook(profile_hook, "cr")

    for _, filter in ipairs(clink.prompt.filters) do
        if filter.f() == true then
            unset_profile_hook()
            return add_ansi_codes(clink.prompt.value)
        end
    end

    unset_profile_hook()
    return add_ansi_codes(clink.prompt.value)
end