From e7a26ebc24cc8e22c84108ec8c6e94a1f1f1bc63 Mon Sep 17 00:00:00 2001
From: Matthew Wild <mwild1@gmail.com>
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
--
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