chore(watchers): refactor events and make debouncer safe

- fs poll -> fs events
- make debouncer safe and fix diagnostics events

doc/nvim-tree-lua.txt

@@ -263,6 +263,7 @@ Subsequent calls to setup will replace the previous configuration.
       diagnostics = {
         enable = false,
         show_on_dirs = false,
+        debounce_delay = 50,
         icons = {
           hint = "",
           info = "",
@@ -328,6 +329,7 @@ Subsequent calls to setup will replace the previous configuration.
           all = false,
           config = false,
           copy_paste = false,
+          dev = false,
           diagnostics = false,
           git = false,
           profile = false,
@@ -471,6 +473,10 @@ Show LSP and COC diagnostics in the signcolumn
     Enable/disable the feature.
       Type: `boolean`, Default: `false`
 
+    *nvim-tree.diagnostics.debounce_delay*
+    Idle milliseconds between diagnostic event and update.
+      Type: `number`, Default: `50` (ms)
+
     *nvim-tree.diagnostics.show_on_dirs*
     Show diagnostic icons on parent directories.
       Type: `boolean`, Default: `false`
@@ -888,6 +894,10 @@ Configuration for diagnostic logging.
         File copy and paste actions.
           Type: `boolean`, Default: `false`
 
+        *nvim-tree.log.types.dev*
+        Used for local development only. Not useful for users.
+          Type: `boolean`, Default: `false`
+
         *nvim-tree.log.types.diagnostics*
         LSP and COC processing, verbose.
           Type: `boolean`, Default: `false`

lua/nvim-tree.lua

@@ -395,11 +395,17 @@ local function setup_autocommands(opts)
 
   if opts.diagnostics.enable then
     create_nvim_tree_autocmd("DiagnosticChanged", {
-      callback = require("nvim-tree.diagnostics").update,
+      callback = function()
+        log.line("diagnostics", "DiagnosticChanged")
+        require("nvim-tree.diagnostics").update()
+      end,
     })
     create_nvim_tree_autocmd("User", {
       pattern = "CocDiagnosticChange",
-      callback = require("nvim-tree.diagnostics").update,
+      callback = function()
+        log.line("diagnostics", "CocDiagnosticChange")
+        require("nvim-tree.diagnostics").update()
+      end,
     })
   end
 end
@@ -511,6 +517,7 @@ local DEFAULT_OPTS = { -- BEGIN_DEFAULT_OPTS
   diagnostics = {
     enable = false,
     show_on_dirs = false,
+    debounce_delay = 50,
     icons = {
       hint = "",
       info = "",
@@ -576,6 +583,7 @@ local DEFAULT_OPTS = { -- BEGIN_DEFAULT_OPTS
       all = false,
       config = false,
       copy_paste = false,
+      dev = false,
       diagnostics = false,
       git = false,
       profile = false,

lua/nvim-tree/core.lua

@@ -10,7 +10,7 @@ local first_init_done = false
 
 function M.init(foldername)
   if TreeExplorer then
-    TreeExplorer:_clear_watchers()
+    TreeExplorer:destroy()
   end
   TreeExplorer = explorer.Explorer.new(foldername)
   if not first_init_done then

lua/nvim-tree/diagnostics.lua

@@ -90,6 +90,7 @@ function M.update()
   if not M.enable or not core.get_explorer() or not view.is_buf_valid(view.get_bufnr()) then
     return
   end
+  utils.debounce("diagnostics", M.debounce_delay, function()
     local ps = log.profile_start "diagnostics update"
     log.line("diagnostics", "update")
 
@@ -127,6 +128,7 @@ function M.update()
       end
     end
     log.profile_end(ps, "diagnostics update")
+  end)
 end
 
 local links = {
@@ -138,6 +140,7 @@ local links = {
 
 function M.setup(opts)
   M.enable = opts.diagnostics.enable
+  M.debounce_delay = opts.diagnostics.debounce_delay
 
   if M.enable then
     log.line("diagnostics", "setup")

lua/nvim-tree/explorer/common.lua

@@ -43,6 +43,16 @@ function M.update_git_status(node, parent_ignored, status)
   end
 end
 
+function M.node_destroy(node)
+  if not node then
+    return
+  end
+
+  if node.watcher then
+    node.watcher:destroy()
+  end
+end
+
 function M.setup(opts)
   M.config = {
     git = opts.git,

lua/nvim-tree/explorer/init.lua

@@ -2,6 +2,7 @@ local uv = vim.loop
 
 local git = require "nvim-tree.git"
 local watch = require "nvim-tree.explorer.watch"
+local common = require "nvim-tree.explorer.common"
 
 local M = {}
 
@@ -33,22 +34,16 @@ function Explorer:expand(node)
   self:_load(node)
 end
 
-function Explorer.clear_watchers_for(root_node)
+function Explorer:destroy()
   local function iterate(node)
-    if node.watcher then
-      node.watcher:stop()
+    common.node_destroy(node)
+    if node.nodes then
       for _, child in pairs(node.nodes) do
-        if child.watcher then
         iterate(child)
       end
     end
   end
-  end
-  iterate(root_node)
-end
-
-function Explorer:_clear_watchers()
-  Explorer.clear_watchers_for(self)
+  iterate(self)
 end
 
 function M.setup(opts)

lua/nvim-tree/explorer/reload.lua

@@ -69,7 +69,12 @@ function M.reload(node, status)
   node.nodes = vim.tbl_map(
     update_status(nodes_by_path, node_ignored, status),
     vim.tbl_filter(function(n)
+      if child_names[n.absolute_path] then
         return child_names[n.absolute_path]
+      else
+        common.node_destroy(n)
+        return nil
+      end
     end, node.nodes)
   )
 

lua/nvim-tree/explorer/watch.lua

@@ -46,7 +46,7 @@ function M.create_watcher(absolute_path)
   end
 
   log.line("watcher", "node start '%s'", absolute_path)
-  Watcher.new {
+  return Watcher.new {
     absolute_path = absolute_path,
     interval = M.interval,
     on_event = function(opts)

lua/nvim-tree/git/init.lua

@@ -29,8 +29,8 @@ function M.reload_project(project_root, path)
     return
   end
 
-  if path and not path:match("^" .. project_root) then
-    path = nil
+  if path and path:find(project_root, 1, true) ~= 1 then
+    return
   end
 
   local git_status = Runner.run {
@@ -43,7 +43,7 @@ function M.reload_project(project_root, path)
 
   if path then
     for p in pairs(project.files) do
-      if p:match("^" .. path) then
+      if p:find(path, 1, true) == 1 then
         project.files[p] = nil
       end
     end
@@ -138,10 +138,6 @@ function M.load_project_status(cwd)
           reload_tree_at(opts.project_root)
         end)
       end,
-      on_event0 = function()
-        log.line("watcher", "git event")
-        M.reload_tree_at(project_root)
-      end,
     }
   end
 

lua/nvim-tree/git/runner.lua

@@ -147,11 +147,11 @@ function Runner.run(opts)
   log.profile_end(ps, "git job %s %s", opts.project_root, opts.path)
 
   if self.rc == -1 then
-    log.line("git", "job timed out")
+    log.line("git", "job timed out  %s %s", opts.project_root, opts.path)
   elseif self.rc ~= 0 then
-    log.line("git", "job failed with return code %d", self.rc)
+    log.line("git", "job fail rc %d %s %s", self.rc, opts.project_root, opts.path)
   else
-    log.line("git", "job success")
+    log.line("git", "job success    %s %s", opts.project_root, opts.path)
   end
 
   return self.output

lua/nvim-tree/utils.lua

@@ -307,25 +307,57 @@ function M.key_by(tbl, key)
   return keyed
 end
 
----Execute callback timeout ms after the lastest invocation with context. Waiting invocations for that context will be discarded. Caller should this ensure that callback performs the same or functionally equivalent actions.
+local function timer_stop_close(timer)
+  if timer:is_active() then
+    timer:stop()
+  end
+  if not timer:is_closing() then
+    timer:close()
+  end
+end
+
+---Execute callback timeout ms after the lastest invocation with context.
+---Waiting invocations for that context will be discarded.
+---Invocation will be rescheduled while a callback is being executed.
+---Caller must ensure that callback performs the same or functionally equivalent actions.
+---
 ---@param context string identifies the callback to debounce
 ---@param timeout number ms to wait
 ---@param callback function to execute on completion
 function M.debounce(context, timeout, callback)
-  if M.debouncers[context] then
-    pcall(uv.close, M.debouncers[context])
+  -- all execution here is done in a synchronous context; no thread safety required
+
+  M.debouncers[context] = M.debouncers[context] or {}
+  local debouncer = M.debouncers[context]
+
+  -- cancel waiting or executing timer
+  if debouncer.timer then
+    timer_stop_close(debouncer.timer)
   end
 
-  M.debouncers[context] = uv.new_timer()
-  M.debouncers[context]:start(
-    timeout,
-    0,
-    vim.schedule_wrap(function()
-      M.debouncers[context]:close()
-      M.debouncers[context] = nil
+  local timer = uv.new_timer()
+  debouncer.timer = timer
+  timer:start(timeout, 0, function()
+    timer_stop_close(timer)
+
+    -- reschedule when callback is running
+    if debouncer.executing then
+      M.debounce(context, timeout, callback)
+      return
+    end
+
+    -- call back at a safe time
+    debouncer.executing = true
+    vim.schedule(function()
       callback()
+      debouncer.executing = false
+
+      -- no other timer waiting
+      if debouncer.timer == timer then
+        M.debouncers[context] = nil
+      end
+    end)
   end)
-  )
 end
 
 function M.focus_file(path)

lua/nvim-tree/watcher.lua

@@ -9,6 +9,13 @@ local M = {
 local Watcher = {}
 Watcher.__index = Watcher
 
+local FS_EVENT_FLAGS = {
+  -- inotify or equivalent will be used; fallback to stat has not yet been implemented
+  stat = false,
+  -- recursive is not functional in neovim's libuv implementation
+  recursive = false,
+}
+
 function Watcher.new(opts)
   for _, existing in ipairs(M._watchers) do
     if existing._opts.absolute_path == opts.absolute_path then
@@ -35,40 +42,47 @@ function Watcher:start()
 
   local rc, _, name
 
-  self._p, _, name = uv.new_fs_poll()
-  if not self._p then
-    self._p = nil
+  self._e, _, name = uv.new_fs_event()
+  if not self._e then
+    self._e = nil
     utils.warn(
-      string.format("Could not initialize an fs_poll watcher for path %s : %s", self._opts.absolute_path, name)
+      string.format("Could not initialize an fs_event watcher for path %s : %s", self._opts.absolute_path, name)
     )
     return nil
   end
 
-  local poll_cb = vim.schedule_wrap(function(err)
+  local event_cb = vim.schedule_wrap(function(err, filename, events)
     if err then
-      log.line("watcher", "poll_cb for %s fail : %s", self._opts.absolute_path, err)
+      log.line("watcher", "event_cb for %s fail : %s", self._opts.absolute_path, err)
     else
+      log.line("watcher", "event_cb '%s' '%s' %s", self._opts.absolute_path, filename, vim.inspect(events))
       self._opts.on_event(self._opts)
     end
   end)
 
-  rc, _, name = uv.fs_poll_start(self._p, self._opts.absolute_path, self._opts.interval, poll_cb)
+  rc, _, name = self._e:start(self._opts.absolute_path, FS_EVENT_FLAGS, event_cb)
   if rc ~= 0 then
-    utils.warn(string.format("Could not start the fs_poll watcher for path %s : %s", self._opts.absolute_path, name))
+    utils.warn(string.format("Could not start the fs_event watcher for path %s : %s", self._opts.absolute_path, name))
     return nil
   end
 
   return self
 end
 
-function Watcher:stop()
-  log.line("watcher", "Watcher:stop  '%s'", self._opts.absolute_path)
-  if self._p then
-    local rc, _, name = uv.fs_poll_stop(self._p)
+function Watcher:destroy()
+  log.line("watcher", "Watcher:destroy '%s'", self._opts.absolute_path)
+  if self._e then
+    local rc, _, name = self._e:stop()
     if rc ~= 0 then
-      utils.warn(string.format("Could not stop the fs_poll watcher for path %s : %s", self._opts.absolute_path, name))
+      utils.warn(string.format("Could not stop the fs_event watcher for path %s : %s", self._opts.absolute_path, name))
+    end
+    self._e = nil
+  end
+  for i, w in ipairs(M._watchers) do
+    if w == self then
+      table.remove(M._watchers, i)
+      break
     end
-    self._p = nil
   end
 end
 
@@ -76,7 +90,7 @@ M.Watcher = Watcher
 
 function M.purge_watchers()
   for _, watcher in pairs(M._watchers) do
-    watcher:stop()
+    watcher:destroy()
   end
   M._watchers = {}
 end