Merge remote-tracking branch 'upstream/master' into colorcolcharcolorcolchar

1 files changed, 223 insertions, 0 deletions

diff --git a/runtime/lua/vim/_watch.lua b/runtime/lua/vim/_watch.lua
new file mode 100644
index 0000000000..43fce3bf7f
--- /dev/null
+++ b/runtime/lua/vim/_watch.lua
@@ -0,0 +1,223 @@
+local M = {}
+local uv = vim.uv
+
+---@enum vim._watch.FileChangeType
+local FileChangeType = {
+  Created = 1,
+  Changed = 2,
+  Deleted = 3,
+}
+
+--- Enumeration describing the types of events watchers will emit.
+M.FileChangeType = vim.tbl_add_reverse_lookup(FileChangeType)
+
+--- 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.uv_fs_event_t|uv.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
+
+--- @class watch.PollOpts
+--- @field debounce? integer
+--- @field include_pattern? vim.lpeg.Pattern
+--- @field exclude_pattern? vim.lpeg.Pattern
+
+---@param path string
+---@param opts watch.PollOpts
+---@param callback function Called on new events
+---@return function cancel stops the watcher
+local function recurse_watch(path, opts, callback)
+  opts = opts or {}
+  local debounce = opts.debounce or 500
+  local uvflags = {}
+  ---@type table<string, uv.uv_fs_event_t> handle by fullpath
+  local handles = {}
+
+  local timer = assert(uv.new_timer())
+
+  ---@type table[]
+  local changesets = {}
+
+  local function is_included(filepath)
+    return opts.include_pattern and opts.include_pattern:match(filepath)
+  end
+  local function is_excluded(filepath)
+    return opts.exclude_pattern and opts.exclude_pattern:match(filepath)
+  end
+
+  local process_changes = function()
+    assert(false, "Replaced later. I'm only here as forward reference")
+  end
+
+  local function create_on_change(filepath)
+    return function(err, filename, events)
+      assert(not err, err)
+      local fullpath = vim.fs.joinpath(filepath, filename)
+      if is_included(fullpath) and not is_excluded(filepath) then
+        table.insert(changesets, {
+          fullpath = fullpath,
+          events = events,
+        })
+        timer:start(debounce, 0, process_changes)
+      end
+    end
+  end
+
+  process_changes = function()
+    ---@type table<string, table[]>
+    local filechanges = vim.defaulttable()
+    for i, change in ipairs(changesets) do
+      changesets[i] = nil
+      if is_included(change.fullpath) and not is_excluded(change.fullpath) then
+        table.insert(filechanges[change.fullpath], change.events)
+      end
+    end
+    for fullpath, events_list in pairs(filechanges) do
+      uv.fs_stat(fullpath, function(_, stat)
+        ---@type vim._watch.FileChangeType
+        local change_type
+        if stat then
+          change_type = FileChangeType.Created
+          for _, event in ipairs(events_list) do
+            if event.change then
+              change_type = FileChangeType.Changed
+            end
+          end
+          if stat.type == 'directory' then
+            local handle = handles[fullpath]
+            if not handle then
+              handle = assert(uv.new_fs_event())
+              handles[fullpath] = handle
+              handle:start(fullpath, uvflags, create_on_change(fullpath))
+            end
+          end
+        else
+          local handle = handles[fullpath]
+          if handle then
+            if not handle:is_closing() then
+              handle:close()
+            end
+            handles[fullpath] = nil
+          end
+          change_type = FileChangeType.Deleted
+        end
+        callback(fullpath, change_type)
+      end)
+    end
+  end
+  local root_handle = assert(uv.new_fs_event())
+  handles[path] = root_handle
+  root_handle:start(path, uvflags, create_on_change(path))
+
+  --- "640K ought to be enough for anyone"
+  --- Who has folders this deep?
+  local max_depth = 100
+
+  for name, type in vim.fs.dir(path, { depth = max_depth }) do
+    local filepath = vim.fs.joinpath(path, name)
+    if type == 'directory' and not is_excluded(filepath) then
+      local handle = assert(uv.new_fs_event())
+      handles[filepath] = handle
+      handle:start(filepath, uvflags, create_on_change(filepath))
+    end
+  end
+  local function cancel()
+    for fullpath, handle in pairs(handles) do
+      if not handle:is_closing() then
+        handle:close()
+      end
+      handles[fullpath] = nil
+    end
+    timer:stop()
+    timer:close()
+  end
+  return 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
+---     - debounce (number|nil)
+---                Time events are debounced in ms. Defaults to 500
+---     - 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 recurse_watch(path, opts, callback)
+end
+
+return M