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util/promise.lua @ 12480:7e9ebdc75ce4
net: isolate LuaSec-specifics
For this, various accessor functions are now provided directly on the
sockets, which reach down into the LuaSec implementation to obtain the
information.
While this may seem of little gain at first, it hides the implementation
detail of the LuaSec+LuaSocket combination that the actual socket and
the TLS layer are separate objects.
The net gain here is that an alternative implementation does not have to
emulate that specific implementation detail and "only" has to expose
LuaSec-compatible data structures on the new functions.
author | Jonas Schäfer <jonas@wielicki.name> |
---|---|
date | Wed, 27 Apr 2022 17:44:14 +0200 |
parent | 11947:073e53b72792 |
child | 12589:39ae08180c81 |
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local promise_methods = {}; local promise_mt = { __name = "promise", __index = promise_methods }; local xpcall = require "util.xpcall".xpcall; local unpack = table.unpack or unpack; --luacheck: ignore 113 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 resolved = false; local function _resolve(v) if resolved then return; end resolved = true; 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 resolved then return; end resolved = true; 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; }