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local M = {}
--- Enumeration describing the types of events watchers will emit.
M.FileChangeType = vim.tbl_add_reverse_lookup({
Created = 1,
Changed = 2,
Deleted = 3,
})
--- Joins filepath elements by static '/' separator
---
---@param ... (string) The path elements.
---@return string
local function filepath_join(...)
return table.concat({ ... }, '/')
end
--- Stops and closes a libuv |uv_fs_event_t| or |uv_fs_poll_t| handle
---
---@param handle (uv_fs_event_t|uv_fs_poll_t) The handle to stop
local function stop(handle)
local _, stop_err = handle:stop()
assert(not stop_err, stop_err)
local is_closing, close_err = handle:is_closing()
assert(not close_err, close_err)
if not is_closing then
handle:close()
end
end
--- Initializes and starts a |uv_fs_event_t|
---
---@param path (string) The path to watch
---@param opts (table|nil) Additional options
--- - uvflags (table|nil)
--- Same flags as accepted by |uv.fs_event_start()|
---@param callback (function) The function called when new events
---@return (function) Stops the watcher
function M.watch(path, opts, callback)
vim.validate({
path = { path, 'string', false },
opts = { opts, 'table', true },
callback = { callback, 'function', false },
})
path = vim.fs.normalize(path)
local uvflags = opts and opts.uvflags or {}
local handle, new_err = vim.uv.new_fs_event()
assert(not new_err, new_err)
local _, start_err = handle:start(path, uvflags, function(err, filename, events)
assert(not err, err)
local fullpath = path
if filename then
filename = filename:gsub('\\', '/')
fullpath = filepath_join(fullpath, filename)
end
local change_type = events.change and M.FileChangeType.Changed or 0
if events.rename then
local _, staterr, staterrname = vim.uv.fs_stat(fullpath)
if staterrname == 'ENOENT' then
change_type = M.FileChangeType.Deleted
else
assert(not staterr, staterr)
change_type = M.FileChangeType.Created
end
end
callback(fullpath, change_type)
end)
assert(not start_err, start_err)
return function()
stop(handle)
end
end
local default_poll_interval_ms = 2000
--- @class watch.Watches
--- @field is_dir boolean
--- @field children? table<string,watch.Watches>
--- @field cancel? fun()
--- @field started? boolean
--- @field handle? uv_fs_poll_t
--- @class watch.PollOpts
--- @field interval? integer
--- @field include_pattern? userdata
--- @field exclude_pattern? userdata
--- Implementation for poll, hiding internally-used parameters.
---
---@param path string
---@param opts watch.PollOpts
---@param callback fun(patch: string, filechangetype: integer)
---@param watches (watch.Watches|nil) A tree structure to maintain state for recursive watches.
--- - handle (uv_fs_poll_t)
--- The libuv handle
--- - cancel (function)
--- A function that cancels the handle and all children's handles
--- - is_dir (boolean)
--- Indicates whether the path is a directory (and the poll should
--- be invoked recursively)
--- - children (table|nil)
--- A mapping of directory entry name to its recursive watches
--- - started (boolean|nil)
--- Whether or not the watcher has first been initialized. Used
--- to prevent a flood of Created events on startup.
---@return fun() Cancel function
local function poll_internal(path, opts, callback, watches)
path = vim.fs.normalize(path)
local interval = opts and opts.interval or default_poll_interval_ms
watches = watches or {
is_dir = true,
}
watches.cancel = function()
if watches.children then
for _, w in pairs(watches.children) do
w.cancel()
end
end
if watches.handle then
stop(watches.handle)
end
end
local function incl_match()
return not opts.include_pattern or opts.include_pattern:match(path) ~= nil
end
local function excl_match()
return opts.exclude_pattern and opts.exclude_pattern:match(path) ~= nil
end
if not watches.is_dir and not incl_match() or excl_match() then
return watches.cancel
end
if not watches.handle then
local poll, new_err = vim.uv.new_fs_poll()
assert(not new_err, new_err)
watches.handle = poll
local _, start_err = poll:start(
path,
interval,
vim.schedule_wrap(function(err)
if err == 'ENOENT' then
return
end
assert(not err, err)
poll_internal(path, opts, callback, watches)
callback(path, M.FileChangeType.Changed)
end)
)
assert(not start_err, start_err)
if watches.started then
callback(path, M.FileChangeType.Created)
end
end
if watches.is_dir then
watches.children = watches.children or {}
local exists = {} --- @type table<string,true>
for name, ftype in vim.fs.dir(path) do
exists[name] = true
if not watches.children[name] then
watches.children[name] = {
is_dir = ftype == 'directory',
started = watches.started,
}
poll_internal(filepath_join(path, name), opts, callback, watches.children[name])
end
end
local newchildren = {} ---@type table<string,watch.Watches>
for name, watch in pairs(watches.children) do
if exists[name] then
newchildren[name] = watch
else
watch.cancel()
watches.children[name] = nil
if watch.handle then
callback(path .. '/' .. name, M.FileChangeType.Deleted)
end
end
end
watches.children = newchildren
end
watches.started = true
return watches.cancel
end
--- Initializes and starts a |uv_fs_poll_t| recursively watching every file underneath the
--- directory at path.
---
---@param path (string) The path to watch. Must refer to a directory.
---@param opts (table|nil) Additional options
--- - interval (number|nil)
--- Polling interval in ms as passed to |uv.fs_poll_start()|. Defaults to 2000.
--- - include_pattern (LPeg pattern|nil)
--- An |lpeg| pattern. Only changes to files whose full paths match the pattern
--- will be reported. Only matches against non-directoriess, all directories will
--- be watched for new potentially-matching files. exclude_pattern can be used to
--- filter out directories. When nil, matches any file name.
--- - exclude_pattern (LPeg pattern|nil)
--- An |lpeg| pattern. Only changes to files and directories whose full path does
--- not match the pattern will be reported. Matches against both files and
--- directories. When nil, matches nothing.
---@param callback (function) The function called when new events
---@return function Stops the watcher
function M.poll(path, opts, callback)
vim.validate({
path = { path, 'string', false },
opts = { opts, 'table', true },
callback = { callback, 'function', false },
})
return poll_internal(path, opts, callback, nil)
end
return M
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