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65ef6fdaee
Problem: LuaLS struggles with the generics used in Nvim's runtime, requiring broad diagnostic suppressions. Indexing is also slow. Solution: Use EmmyLua for type checks in the build and CI. It offers more sophisticated type checking, substantially better support for generics, and much better flow analysis. Correct the affected annotations. Use `@internal`, supported directly by EmmyLua, instead of `@nodoc` for shared internal declarations, and support it in the help parser. AI-assisted
131 lines
3.8 KiB
Lua
131 lines
3.8 KiB
Lua
local F = vim.F
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local new_event = require('vim.async._event')
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local pcall = pcall
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do
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local ok, coxpcall = pcall(require, 'coxpcall')
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if ok and type(coxpcall) == 'table' and type(coxpcall.pcall) == 'function' then
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pcall = coxpcall.pcall
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end
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end
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local validate = vim.validate
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--- A semaphore manages an internal permit counter. [Semaphore:acquire()]
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--- consumes one permit and [Semaphore:release()] returns one permit. If no
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--- permits are available, `acquire()` suspends the current task until another
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--- task releases one.
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---
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--- The preferred way to use a Semaphore is with the `with()` method, which
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--- automatically acquires and releases the semaphore around a function call.
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--- This is useful for limiting sections that start external work and then
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--- await it, such as file reads, requests, or subprocesses.
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---
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--- ```lua
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--- local async = vim.async
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---
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--- async.run(function()
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--- local limit = async.semaphore(4)
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--- local tasks = {}
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---
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--- for _, path in ipairs(paths) do
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--- table.insert(tasks, async.run(function()
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--- return limit:with(function()
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--- return read_file(path)
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--- end)
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--- end))
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--- end
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---
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--- local next_task = async.iter(tasks)
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--- while true do
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--- local task = next_task()
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--- if task == nil then
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--- break
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--- end
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--- async.await(task)
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--- end
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--- end)
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--- ```
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--- @class vim.async.Semaphore
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--- @field private _permits integer
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--- @field private _max_permits integer
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--- @field package _event vim.async.Event
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local Semaphore = {}
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Semaphore.__index = Semaphore
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--- Executes a function while holding one semaphore permit.
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---
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--- This acquires the semaphore before running the function and releases it
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--- after the function completes, even if it errors or the current task is
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--- closed.
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--- @async
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--- @generic R
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--- @param fn async fun(): R... # Function to execute within the semaphore's context.
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--- @return R... # Result(s) of the executed function.
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function Semaphore:with(fn)
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self:acquire()
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-- This pcall is only a try/finally guard for release(); all errors are
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-- immediately rethrown so it is not an async recovery boundary.
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local r = F.pack_len(pcall(fn))
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self:release()
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local stat = r[1]
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if not stat then
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local err = r[2]
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error(err, 0)
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end
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return unpack(r, 2, r.n)
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end
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--- Acquire a semaphore permit.
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---
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--- If the internal counter is greater than zero, decrement it by `1` and
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--- return immediately. If it is `0`, wait until [Semaphore:release()] is
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--- called.
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--- @async
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function Semaphore:acquire()
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self._event:wait()
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self._permits = self._permits - 1
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assert(self._permits >= 0, 'Semaphore value is negative')
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if self._permits == 0 then
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self._event:clear()
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end
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end
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--- Release a semaphore permit.
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---
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--- Increments the internal counter by `1` and can wake a task waiting in
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--- [Semaphore:acquire()].
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---
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--- Calling this more times than permits were acquired raises an error.
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function Semaphore:release()
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if self._permits >= self._max_permits then
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error('Semaphore value is greater than max permits', 2)
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end
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self._permits = self._permits + 1
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self._event:set(1)
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end
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--- Create an async semaphore that allows up to a given number of acquisitions.
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---
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--- Prefer [Semaphore:with()] for most uses so permits are released reliably.
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--- Use [Semaphore:acquire()] and [Semaphore:release()] directly only when the
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--- acquire and release points cannot be expressed as one function call.
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--- @param permits? integer (default: 1)
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--- @return vim.async.Semaphore
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local function new_semaphore(permits)
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validate('permits', permits, 'number', true)
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permits = permits or 1
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if permits < 1 or permits % 1 ~= 0 then
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error('permits: expected positive integer', 2)
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end
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local obj = setmetatable({
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_max_permits = permits,
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_permits = permits,
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_event = new_event(),
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}, Semaphore)
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obj._event:set()
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return obj
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end
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return new_semaphore
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