local log = require("nvim-tree.log")

local git = require("nvim-tree.git")

local utils = require("nvim-tree.utils")

local notify = require("nvim-tree.notify")

local config = require("nvim-tree.config")

local Watcher = require("nvim-tree.watcher").Watcher

local M = {}

-- monotonically increasing, unique

local uid = 0

---@param path string

---@return boolean

local function is_git(path)

-- If $GIT_DIR is set, consider its value to be equivalent to '.git'.

-- Expand $GIT_DIR (and `path`) to a full path (see :help filename-modifiers), since

-- it's possible to set it to a relative path. We want to make our best

-- effort to expand that to a valid absolute path.

if vim.fn.fnamemodify(path, ":p") == vim.fn.fnamemodify(vim.env.GIT_DIR, ":p") then

return true

elseif vim.fn.fnamemodify(path, ":t") == ".git" then

return true

else

return false

end

end

local IGNORED_PATHS = {

-- disable watchers on kernel filesystems

-- which have a lot of unwanted events

"/sys",

"/proc",

"/dev",

}

---Return true when a path is:

---- Blacklisted via {ignore_dirs}

---- Not whitelisted via {whitelist_dirs}, when it is not an empty table.

---@param path string

---@return boolean

local function is_folder_ignored(path)

for _, folder in ipairs(IGNORED_PATHS) do

if vim.startswith(path, folder) then

return true

end

end

---Return true when p matches an entry in dirs, escaping for windows

---@param p string absolute path

---@param dirs string[] regexes

---@return boolean

local function matches_dirs(p, dirs)

for _, dir in ipairs(dirs) do

if config.os.windows then

dir = dir:gsub("/", "\\\\") or dir

end

if vim.fn.match(p, dir) ~= -1 then

return true

end

end

return false

end

if type(config.g.filesystem_watchers.ignore_dirs) == "table" then

if matches_dirs(path, config.g.filesystem_watchers.ignore_dirs --[[@as string[] ]]) then

return true

end

elseif type(config.g.filesystem_watchers.ignore_dirs) == "function" then

if config.g.filesystem_watchers.ignore_dirs(path) then

return true

end

end

if type(config.g.filesystem_watchers.whitelist_dirs) == "table" and #config.g.filesystem_watchers.whitelist_dirs > 0 then

if not matches_dirs(path, config.g.filesystem_watchers.whitelist_dirs --[[@as string[] ]]) then

return true

end

elseif type(config.g.filesystem_watchers.whitelist_dirs) == "function" then

if not config.g.filesystem_watchers.whitelist_dirs(path) then

return true

end

end

return false

end

---@param node DirectoryNode

---@return Watcher|nil

function M.create_watcher(node)

if not config.g.filesystem_watchers.enable or type(node) ~= "table" then

return nil

end

local path = node.link_to or node.absolute_path

if is_git(path) or is_folder_ignored(path) then

return nil

end

---@param watcher Watcher

local function callback(watcher)

log.line("watcher", "node event scheduled refresh %s", watcher.data.context)

-- event is awaiting debouncing and handling

watcher.data.outstanding_events = watcher.data.outstanding_events + 1

-- disable watcher when outstanding exceeds max

if config.g.filesystem_watchers.max_events > 0 and watcher.data.outstanding_events > config.g.filesystem_watchers.max_events then

notify.error(string.format(

"Observed %d consecutive file system events with interval < %dms, exceeding filesystem_watchers.max_events=%s. Disabling watcher for directory '%s'. Consider adding this directory to filesystem_watchers.ignore_dirs",

watcher.data.outstanding_events,

config.g.filesystem_watchers.debounce_delay,

config.g.filesystem_watchers.max_events,

node.absolute_path

))

node:destroy_watcher()

end

utils.debounce(watcher.data.context, config.g.filesystem_watchers.debounce_delay, function()

if watcher.destroyed then

return

end

-- event has been handled

watcher.data.outstanding_events = 0

if node.link_to then

log.line("watcher", "node event executing refresh '%s' -> '%s'", node.link_to, node.absolute_path)

else

log.line("watcher", "node event executing refresh '%s'", node.absolute_path)

end

git.refresh_dir(node)

end)

end

uid = uid + 1

return Watcher:create({

path = path,

callback = callback,

data = {

context = "explorer:watch:" .. path .. ":" .. uid,

outstanding_events = 0, -- unprocessed events that have not been debounced

}

})

end

return M