mirror of
https://github.com/sbrl/Minetest-WorldEditAdditions.git
synced 2024-12-03 20:43:50 +01:00
promise/sbrl: bugfix
it should work in most situations now.
This commit is contained in:
Starbeamrainbowlabs
parent
3ccea536c8
commit
f654bde966
147
promise.lua
147
promise.lua
@ -1,3 +1,5 @@
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local inspect = require("worldeditadditions_core.utils.inspect")
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--- Javascript Promises, implemented in Lua
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-- In other words, a wrapper to manage asynchronous operations.
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-- Due to limitations of Lua, while this Promise API is similar it isn't exactly the same as in JS. Most notably is that there is a .run() function you must call AFTER you call .then_() as many times as you need.
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@ -15,92 +17,73 @@ Promise.__name = "Promise" -- A hack to allow identification in wea.inspect
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function Promise.new(fn)
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local result = {
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state = "pending",
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fns = { { then_ = fn } }
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fns = { { fn_then_ = fn } }
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}
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setmetatable(result, Promise)
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return result
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end
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-- NOTE: fn_catch support is NOT FULLY IMPLEMENTED yet!
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-- Example: It doesn't work when calling non-async .then()s!
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function Promise.then_(self, fn_then, fn_catch)
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local step_item = {
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then_ = fn_then,
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}
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if type(fn_catch) == "function" then
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step_item.catch_ = fn_catch
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end
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table.insert(self.fns, step_item)
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return self
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------------------------------------------------------------------------
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local do_unpack = unpack
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if not do_unpack then do_unpack = table.unpack end
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if not do_unpack then
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error("Error: Failed to find unpack implementation")
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end
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--- Executes the function this Promise is wrapping all associated chained functions in sequence.
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-- This is a separate method for portability, since Lua does not implement setTimeout which is required to ensure that if an non-async function is wrapped the parent function still has time to call .then_() before it finishes and the associated .then_()ed functions are attached correctly.
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--
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-- WARNING: If you call .then_() AFTER calling .run(), your .then_()ed function may not be called correctly!
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-- @returns Promise The current promise, for daisy chaining purposes.
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function Promise.run(self)
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-- TODO update self.state here
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do_run(promise, {}, 1, function(...)
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end)
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return self
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end
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local function do_run(promise, args, depth, origin_resolve)
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-- print("DO_RUN promise", inspect(promise), "args", inspect(args), "depth", depth, "origin_resolve", origin_resolve)
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---
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-- 0: Termination condition
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---
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if #promise.fns == 0 then
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promise.state = "fulfilled"
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origin_resolve(table.unpack(args))
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origin_resolve(do_unpack(args))
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return
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end
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---
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-- 1: Sort out inputs
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---
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if args == nil then args = {} end
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local next = table.remove(promise.fns, 1)
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local do_next_fn = function(args)
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do_run(promise, args, depth + 1)
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local do_next_fn = function(args_to_pass)
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do_run(promise, args_to_pass, depth + 1, origin_resolve)
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end
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---
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-- 2: Run teh function!
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---
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-- (if it's the 1st one in the sequence we treat it specially)
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local results
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if depth == 1 then
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-- This function is the inner one of a promise already.
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-- It has already recieved arguments, so it expected resolve/reject instead
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next.then_(function(...) -- RESOLVE
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next.fn_then_(function(...) -- RESOLVE
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if getmetatable(arg[1]) == Promise then
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promise.state = "rejected"
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error("Error: Returning nested Promises is not currently supported.")
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end
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do_next_fn(args) -- Execute the next one in the sequence
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do_next_fn(arg) -- Execute the next one in the sequence
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end, function(...) -- REJECT
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promise.state = "rejected"
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if type(next.catch_) == "function" then
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next.catch_(table.unpack(arg))
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if type(next.fn_catch_) == "function" then
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next.fn_catch_(do_unpack(arg))
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else
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error("Error: Promise rejected but no catch function present. TODO make this error message more useful and informative.")
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error(
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"Error: Promise rejected but no catch function present. TODO make this error message more useful and informative.")
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-- If there's no catch registered, throw an error
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end
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end)
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else
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results = { next.then_(table.unpack(args)) }
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results = { next.fn_then_(do_unpack(args)) }
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---
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-- 3: Handle the aftermath
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---
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@ -121,35 +104,67 @@ local function do_run(promise, args, depth, origin_resolve)
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do_next_fn(results)
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end
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end
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end
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------------------------------------------------------------------------
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-- NOTE: fn_catch support is NOT FULLY IMPLEMENTED yet!
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-- Example: It doesn't work when calling non-async .then()s!
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function Promise.then_(self, fn_then, fn_catch)
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local step_item = {
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fn_then_ = fn_then,
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}
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if type(fn_catch) == "function" then
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step_item.fn_catch_ = fn_catch
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end
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table.insert(self.fns, step_item)
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return self
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end
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--- Executes the function this Promise is wrapping all associated chained functions in sequence.
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-- This is a separate method for portability, since Lua does not implement setTimeout which is required to ensure that if an non-async function is wrapped the parent function still has time to call .then_() before it finishes and the associated .then_()ed functions are attached correctly.
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--
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-- WARNING: If you call .then_() AFTER calling .run(), your .then_()ed function may not be called correctly!
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-- @returns Promise The current promise, for daisy chaining purposes.
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function Promise.run(self)
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-- TODO update self.state here
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do_run(self, {}, 1, function(...)
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end)
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return self
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end
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return Promise
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-- return Promise
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-- TEST example code, TODO test this
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-- function test()
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-- return Promise.new(function(resolve, reject)
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-- -- TODO do something asyncy here
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-- print("DEBUG running test function")
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-- resolve(4)
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-- end)
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-- end
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function test()
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return Promise.new(function(resolve, reject)
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-- TODO do something asyncy here
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print("DEBUG running test function")
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resolve(4)
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end)
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end
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-- test()
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-- .then_(function(val)
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-- print("DEBUG then #1 VAL", val)
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-- return val * 2
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-- end)
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-- .then_(function(val)
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-- print("DEBUG then #2 VAL", val)
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-- return math.sqrt(val)
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-- end)
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-- .then_(function(val)
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-- print("DEBUG then #3 VAL", val)
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-- end)
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-- .run()
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test()
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:then_(function(val)
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print("DEBUG then #1 VAL", val)
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return val * 2
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end)
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:then_(function(val)
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print("DEBUG then #2 VAL", val)
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return math.sqrt(val)
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end)
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:then_(function(val)
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print("DEBUG then #3 VAL", val)
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end)
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:run()
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