【Lua实战】表的序列化：配置存档与恢复的回路

---表的序列化：递归生成可 load 的代码
local function serialize(v, indent)
    indent = indent or ''
    if type(v) == 'string' then
        return string.format('%q', v)
    elseif type(v) == 'table' then
        local out = { '{' }
        for k, val in pairs(v) do
            local key = (type(k) == 'string')
                and ('["' .. k .. '"]')
                or ('[' .. k .. ']')
            out[#out + 1] = indent .. '  ' .. key .. ' = '
                .. serialize(val, indent .. '  ') .. ','
        end
        out[#out + 1] = indent .. '}'
        return table.concat(out, '\n')
    end
    return tostring(v)
end

---反序列化：load 编译执行
local function deserialize(code)
    local fn, err = load(code, 'snapshot', 't', {})
    if not fn then return nil, err end
    local ok, result = pcall(fn)
    if not ok then return nil, result end
    return result
end

---活动状态的中途存档与恢复
function ActState.save(state)
    local code = 'return ' .. serialize(state)
    DB.exec('UPDATE act_state SET code = ?', code)
end

function ActState.restore()
    local row = DB.queryRow('SELECT code FROM act_state')
    if not row then return nil end
    return deserialize(row.code)
end