util.startup: Check root after detecting platform and reading config (thanks SigmaTel71)
Ensures that startup.detect_platform() runs so know whether to use the
POSIX method of checking the current user or something else. Also after
reading the config so we know whether the root override setting is set.
local function _remove(list, m)
if m.prev then
m.prev.next = m.next;
end
if m.next then
m.next.prev = m.prev;
end
if list._tail == m then
list._tail = m.prev;
end
if list._head == m then
list._head = m.next;
end
list._count = list._count - 1;
end
local function _insert(list, m)
if list._head then
list._head.prev = m;
end
m.prev, m.next = nil, list._head;
list._head = m;
if not list._tail then
list._tail = m;
end
list._count = list._count + 1;
end
local cache_methods = {};
local cache_mt = { __name = "cache", __index = cache_methods };
function cache_methods:set(k, v)
local m = self._data[k];
if m then
-- Key already exists
if v ~= nil then
-- Bump to head of list
_remove(self, m);
_insert(self, m);
m.value = v;
else
-- Remove from list
_remove(self, m);
self._data[k] = nil;
end
return true;
end
-- New key
if v == nil then
return true;
end
-- Check whether we need to remove oldest k/v
if self._count == self.size then
local tail = self._tail;
local on_evict, evicted_key, evicted_value = self._on_evict, tail.key, tail.value;
local do_evict = on_evict and on_evict(evicted_key, evicted_value, self);
if do_evict == false then
-- Cache is full, and we're not allowed to evict
return false;
elseif self._count == self.size then
-- Cache wasn't grown
_remove(self, tail);
self._data[evicted_key] = nil;
end
end
m = { key = k, value = v, prev = nil, next = nil };
self._data[k] = m;
_insert(self, m);
return true;
end
function cache_methods:get(k)
local m = self._data[k];
if m then
return m.value;
end
return nil;
end
function cache_methods:items()
local m = self._head;
return function ()
if not m then
return;
end
local k, v = m.key, m.value;
m = m.next;
return k, v;
end
end
function cache_methods:values()
local m = self._head;
return function ()
if not m then
return;
end
local v = m.value;
m = m.next;
return v;
end
end
function cache_methods:count()
return self._count;
end
function cache_methods:head()
local head = self._head;
if not head then return nil, nil; end
return head.key, head.value;
end
function cache_methods:tail()
local tail = self._tail;
if not tail then return nil, nil; end
return tail.key, tail.value;
end
function cache_methods:resize(new_size)
new_size = assert(tonumber(new_size), "cache size must be a number");
new_size = math.floor(new_size);
assert(new_size > 0, "cache size must be greater than zero");
local on_evict = self._on_evict;
while self._count > new_size do
local tail = self._tail;
local evicted_key, evicted_value = tail.key, tail.value;
if on_evict ~= nil and (on_evict == false or on_evict(evicted_key, evicted_value, self) == false) then
-- Cache is full, and we're not allowed to evict
return false;
end
_remove(self, tail);
self._data[evicted_key] = nil;
end
self.size = new_size;
return true;
end
function cache_methods:table()
--luacheck: ignore 212/t
if not self.proxy_table then
self.proxy_table = setmetatable({}, {
__index = function (t, k)
return self:get(k);
end;
__newindex = function (t, k, v)
if not self:set(k, v) then
error("failed to insert key into cache - full");
end
end;
__pairs = function (t)
return self:items();
end;
__len = function (t)
return self:count();
end;
});
end
return self.proxy_table;
end
function cache_methods:clear()
self._data = {};
self._count = 0;
self._head = nil;
self._tail = nil;
end
local function new(size, on_evict)
size = assert(tonumber(size), "cache size must be a number");
size = math.floor(size);
assert(size > 0, "cache size must be greater than zero");
local data = {};
return setmetatable({ _data = data, _count = 0, size = size, _head = nil, _tail = nil, _on_evict = on_evict }, cache_mt);
end
return {
new = new;
}