mod_posix: Move everything to util.startup
This allows greater control over the order of events.
Notably, the internal ordering between daemonization, initialization of
libunbound and setup of signal handling is sensitive.
libunbound starts a separate thread for processing DNS requests.
If this thread is started before signal handling has been set up, it
will not inherit the signal handlers and instead behave as it would have
before signal handlers were set up, i.e. cause the whole process to
immediately exit.
libunbound is usually initialized on the first DNS request, usually
triggered by an outgoing s2s connection attempt.
If daemonization happens before signals have been set up, signals may
not be processed at all.
local promise_methods = {};
local promise_mt = { __name = "promise", __index = promise_methods };
local xpcall = require "prosody.util.xpcall".xpcall;
local unpack = table.unpack;
function promise_mt:__tostring()
return "promise (" .. (self._state or "invalid") .. ")";
end
local function is_promise(o)
local mt = getmetatable(o);
return mt == promise_mt;
end
local function wrap_handler(f, resolve, reject, default)
if not f then
return default;
end
return function (param)
local ok, ret = xpcall(f, debug.traceback, param);
if ok then
resolve(ret);
else
reject(ret);
end
return true;
end;
end
local function next_pending(self, on_fulfilled, on_rejected, resolve, reject)
table.insert(self._pending_on_fulfilled, wrap_handler(on_fulfilled, resolve, reject, resolve));
table.insert(self._pending_on_rejected, wrap_handler(on_rejected, resolve, reject, reject));
end
local function next_fulfilled(promise, on_fulfilled, on_rejected, resolve, reject) -- luacheck: ignore 212/on_rejected
wrap_handler(on_fulfilled, resolve, reject, resolve)(promise.value);
end
local function next_rejected(promise, on_fulfilled, on_rejected, resolve, reject) -- luacheck: ignore 212/on_fulfilled
wrap_handler(on_rejected, resolve, reject, reject)(promise.reason);
end
local function promise_settle(promise, new_state, new_next, cbs, value)
if promise._state ~= "pending" then
return;
end
promise._state = new_state;
promise._next = new_next;
for _, cb in ipairs(cbs) do
cb(value);
end
-- No need to keep references to callbacks
promise._pending_on_fulfilled = nil;
promise._pending_on_rejected = nil;
return true;
end
local function new_resolve_functions(p)
local function _resolve(v)
if is_promise(v) then
v:next(new_resolve_functions(p));
elseif promise_settle(p, "fulfilled", next_fulfilled, p._pending_on_fulfilled, v) then
p.value = v;
end
end
local function _reject(e)
if promise_settle(p, "rejected", next_rejected, p._pending_on_rejected, e) then
p.reason = e;
end
end
return _resolve, _reject;
end
local next_tick = function (f)
f();
end
local function new(f)
local p = setmetatable({ _state = "pending", _next = next_pending, _pending_on_fulfilled = {}, _pending_on_rejected = {} }, promise_mt);
if f then
next_tick(function()
local resolve, reject = new_resolve_functions(p);
local ok, ret = xpcall(f, debug.traceback, resolve, reject);
if not ok and p._state == "pending" then
reject(ret);
end
end);
end
return p;
end
local function all(promises)
return new(function (resolve, reject)
local settled, results, loop_finished = 0, {}, false;
local total = 0;
for k, v in pairs(promises) do
if is_promise(v) then
total = total + 1;
v:next(function (value)
results[k] = value;
settled = settled + 1;
if settled == total and loop_finished then
resolve(results);
end
end, reject);
else
results[k] = v;
end
end
loop_finished = true;
if settled == total then
resolve(results);
end
end);
end
local function all_settled(promises)
return new(function (resolve)
local settled, results, loop_finished = 0, {}, false;
local total = 0;
for k, v in pairs(promises) do
if is_promise(v) then
total = total + 1;
v:next(function (value)
results[k] = { status = "fulfilled", value = value };
settled = settled + 1;
if settled == total and loop_finished then
resolve(results);
end
end, function (e)
results[k] = { status = "rejected", reason = e };
settled = settled + 1;
if settled == total and loop_finished then
resolve(results);
end
end);
else
results[k] = v;
end
end
loop_finished = true;
if settled == total then
resolve(results);
end
end);
end
local function join(handler, ...)
local promises, n = { ... }, select("#", ...);
return all(promises):next(function (results)
return handler(unpack(results, 1, n));
end);
end
local function race(promises)
return new(function (resolve, reject)
for i = 1, #promises do
promises[i]:next(resolve, reject);
end
end);
end
local function resolve(v)
return new(function (_resolve)
_resolve(v);
end);
end
local function reject(v)
return new(function (_, _reject)
_reject(v);
end);
end
local function try(f)
return resolve():next(function () return f(); end);
end
function promise_methods:next(on_fulfilled, on_rejected)
return new(function (resolve, reject) --luacheck: ignore 431/resolve 431/reject
self:_next(on_fulfilled, on_rejected, resolve, reject);
end);
end
function promise_methods:catch(on_rejected)
return self:next(nil, on_rejected);
end
function promise_methods:finally(on_finally)
local function _on_finally(value) on_finally(); return value; end
local function _on_catch_finally(err) on_finally(); return reject(err); end
return self:next(_on_finally, _on_catch_finally);
end
return {
new = new;
resolve = resolve;
join = join;
reject = reject;
all = all;
all_settled = all_settled;
race = race;
try = try;
is_promise = is_promise;
set_nexttick = function(new_next_tick) next_tick = new_next_tick; end;
}