bspwm/examples/external_rules/lua/ruld

#! /usr/bin/env lua

local p = require("posix")
local port = 54321

local short = "hp:"
local long = {
    {"help", "none", 'h'},
    {"port", "required", 'p'},
}

local rules = {}

for opt, optarg, optind, longind in p.getopt(arg, short, long) do
    if opt == '?' then
        print("Unrecognized option")
        os.exit(1)
    elseif opt == 'h' then
        print("Usage: ruld [-h|-p PORT]")
        os.exit(0)
    elseif opt == 'p' then
        port = optarg
    end
end

function eval(exp, env)
    local f
    local value = "return " .. exp
    if env then
        f = load(value, nil, nil, env)
    else
        f = load(value)
    end
    return f and f()
end

function test(env)
    local rsp = ""
    for index = #rules, 1, -1 do
        local entry = rules[index]
        if eval(entry[1], env) then
            local delay, duration
            if entry[3] then
                delay = entry[3].delay
                duration = entry[3].duration
                if delay and delay > 0 then
                    entry[3].delay = delay - 1
                end
                if ((not delay) or delay == 0) and duration and duration > 0 then
                    entry[3].duration = duration - 1
                end
            end
            if (((not delay) or delay == 0) and ((not duration) or duration > 0)) then
                if #rsp > 0 then
                    rsp = rsp .. " " .. entry[2]
                else
                    rsp = entry[2]
                end
            end
            if duration and duration <= 1 then
                table.remove(rules, index)
            end
        end
    end
    return rsp
end

local fd = p.socket(p.AF_INET, p.SOCK_STREAM, 0)
p.setsockopt(fd, p.SOL_SOCKET, p.SO_REUSEADDR, 1)
p.bind(fd, {family=p.AF_INET, addr="127.0.0.1", port=port})
p.listen(fd, p.SOMAXCONN)
local running = true

while running do
    ret_fd = p.accept(fd)
    if ret_fd then
        local msg = p.recv(ret_fd, p.BUFSIZ)
        if msg then
            local cmd, data = nil
            sep = msg:find(" ")
            if sep then
                cmd = msg:sub(1, sep - 1)
                data = msg:sub(sep + 1)
            else
                cmd = msg
            end
            if cmd == "test" then
                local env = eval(data)
                if env then
                    rsp = test(env)
                    p.send(ret_fd, rsp)
                end
            elseif cmd == "add" then
                local value = eval(data)
                if value then
                    table.insert(rules, value)
                end
            elseif cmd == "remove" then
                if data == "tail" then
                    table.remove(rules, #rules)
                elseif data == "head" then
                    table.remove(rules, 1)
                else
                    for index = #rules, 1, -1 do
                        if rules[index][1]:find(data) then
                            table.remove(rules, index)
                        end
                    end
                end
            elseif cmd == "quit" then
                running = false
            elseif cmd == "list" then
                local rsp = ""
                for index, entry in pairs(rules) do
                    rsp = rsp .. string.format("%s => %s", entry[1], entry[2])
                    if entry[3] then
                        if entry[3].delay then
                            rsp = rsp .. string.format(" @%i", entry[3].delay)
                        end
                        if entry[3].duration then
                            rsp = rsp .. string.format(" +%i", entry[3].duration)
                        end
                    end
                    if index < #rules then
                        rsp = rsp .. "\n"
                    end
                end
                p.send(ret_fd, rsp)
            end
        end
        p.close(ret_fd)
    end
end

p.close(fd)