mirrors/prosody
1
0
Fork 0
mirror of https://github.com/bjc/prosody.git synced 2025-04-03 21:27:38 +03:00
Code Issues Projects Releases Packages Wiki Activity Actions

util.promise: Ensure chained promises always receive a value/rejection even if an intermediate promise has no handlers

Browse source
This commit is contained in:
Matthew Wild 2018-10-25 14:38:00 +01:00
parent c7d9ee0bb8
commit b74a643e34
2 changed files with 60 additions and 22 deletions
Download patch file Download diff file Expand all files Collapse all files

37
spec/util_promise_spec.lua
View file

@ -138,6 +138,43 @@ describe("util.promise", function ()
assert.equal("ok", result);
end);
it("propagates errors down the chain, even when some handlers are not provided", function ()
local r, result;
local test_error = {};
local p = promise.new(function (resolve, reject)
r = resolve;
end);
local cb = spy.new(function () end);
local err_cb = spy.new(function (e) result = e end);
local p2 = p:next(function () error(test_error) end);
local p3 = p2:next(cb)
p3:catch(err_cb);
assert.spy(cb).was_called(0);
assert.spy(err_cb).was_called(0);
r("oh doh");
assert.spy(cb).was_called(0);
assert.spy(err_cb).was_called(1);
assert.equal(test_error, result);
end);
it("propagates values down the chain, even when some handlers are not provided", function ()
local r;
local p = promise.new(function (resolve, reject)
r = resolve;
end);
local cb = spy.new(function () end);
local err_cb = spy.new(function () end);
local p2 = p:next(function (v) return v; end);
local p3 = p2:catch(err_cb)
p3:next(cb);
assert.spy(cb).was_called(0);
assert.spy(err_cb).was_called(0);
r(1337);
assert.spy(cb).was_called(1);
assert.spy(cb).was_called_with(1337);
assert.spy(err_cb).was_called(0);
end);
describe("race()", function ()
it("works with fulfilled promises", function ()
local p1, p2 = promise.resolve("yep"), promise.resolve("nope");

45
util/promise.lua
View file

@ -10,17 +10,32 @@ local function is_promise(o)
return mt == promise_mt;
end
local function next_pending(self, on_fulfilled, on_rejected)
table.insert(self._pending_on_fulfilled, on_fulfilled);
table.insert(self._pending_on_rejected, on_rejected);
local function wrap_handler(f, resolve, reject, default)
if not f then
return default;
end
return function (param)
local ok, ret = pcall(f, param);
if ok then
resolve(ret);
else
reject(ret);
end
return true;
end;
end
local function next_fulfilled(promise, on_fulfilled, on_rejected) -- luacheck: ignore 212/on_rejected
on_fulfilled(promise.value);
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_rejected(promise, on_fulfilled, on_rejected) -- luacheck: ignore 212/on_fulfilled
on_rejected(promise.reason);
local function next_fulfilled(promise, on_fulfilled, on_rejected, resolve, reject) -- luacheck: ignore 212/on_rejected
wrap_handler(on_fulfilled, resolve, reject)(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)(promise.reason);
end
local function promise_settle(promise, new_state, new_next, cbs, value)
@ -59,17 +74,6 @@ local function new_resolve_functions(p)
return _resolve, _reject;
end
local function wrap_handler(f, resolve, reject)
return function (param)
local ok, ret = pcall(f, param);
if ok then
resolve(ret);
else
reject(ret);
end
end;
end
local function new(f)
local p = setmetatable({ _state = "pending", _next = next_pending, _pending_on_fulfilled = {}, _pending_on_rejected = {} }, promise_mt);
if f then
@ -123,10 +127,7 @@ end
function promise_methods:next(on_fulfilled, on_rejected)
return new(function (resolve, reject) --luacheck: ignore 431/resolve 431/reject
self:_next(
on_fulfilled and wrap_handler(on_fulfilled, resolve, reject) or nil,
on_rejected and wrap_handler(on_rejected, resolve, reject) or nil
);
self:_next(on_fulfilled, on_rejected, resolve, reject);
end);
end