From b74a643e349651c8161512c3180c32da7c6665c0 Mon Sep 17 00:00:00 2001 From: Matthew Wild Date: Thu, 25 Oct 2018 14:38:00 +0100 Subject: util.promise: Ensure chained promises always receive a value/rejection even if an intermediate promise has no handlers --- util/promise.lua | 45 +++++++++++++++++++++++---------------------- 1 file changed, 23 insertions(+), 22 deletions(-) (limited to 'util') diff --git a/util/promise.lua b/util/promise.lua index c0176211..fa09a01c 100644 --- a/util/promise.lua +++ b/util/promise.lua @@ -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_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) -- luacheck: ignore 212/on_rejected - on_fulfilled(promise.value); +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) -- luacheck: ignore 212/on_fulfilled - on_rejected(promise.reason); +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 -- cgit v1.2.3