Pure Lua implementation of CraftOS `fs.find`

find.lua

-- Licensed as CC0
local expect = dofile "/rom/modules/main/cc/expect.lua"

local function splitPath(p)
    local retval = {}
    for m in p:gmatch("[^/]+") do table.insert(retval, m) end
    return retval
end

local function aux_find(parts, p)
    local ok, t = pcall(fs.list, p or "")
    if #parts == 0 then return fs.getName(p) elseif not ok then return nil end
    local parts2 = {}
    for i, v in ipairs(parts) do parts2[i] = v end
    local name = table.remove(parts2, 1)
    local retval = {}
    for _, k in pairs(t) do if k:match("^" .. name:gsub("([%%%.])", "%%%1"):gsub("%*", "%.%*") .. "$") then retval[k] = aux_find(parts2, fs.combine(p or "", k)) end end
    return retval
end

local function combineKeys(t, prefix)
    prefix = prefix or ""
    if t == nil then return {} end
    local retval = {}
    for k,v in pairs(t) do
        if type(v) == "string" then table.insert(retval, prefix .. k)
        else for _,w in ipairs(combineKeys(v, prefix .. k .. "/")) do table.insert(retval, w) end end
    end
    return retval
end

local function find(wildcard)
    expect(1, wildcard, "string")
    local retval = {}
    for _,v in ipairs(combineKeys(aux_find(splitPath(wildcard)))) do table.insert(retval, v) end
    table.sort(retval)
    return retval
end

return find