Diffview auto-refresh, yank file path key bindings

lua/custom/directory-watcher.lua

@@ -0,0 +1,96 @@
+-- Custom directory watcher using Neovim's built-in libuv bindings
+-- Source: https://github.com/richardgill/nix/blob/ebdd8260f770d242db7b6163158cfe9ad9784c41/modules/home-manager/dot-files/nvim/lua/custom/directory-watcher.lua
+
+local M = {}
+
+local uv = vim.uv
+local watcher = nil
+local debounce_timer = nil
+local on_change_handlers = {}
+
+-- Debounce helper to prevent callback storms
+local debounce = function(fn, delay)
+  return function(...)
+    local args = { ... }
+    if debounce_timer then
+      debounce_timer:close()
+    end
+    debounce_timer = vim.defer_fn(function()
+      debounce_timer = nil
+      fn(unpack(args))
+    end, delay)
+  end
+end
+
+-- Register a named handler to be called when files change
+-- If a handler with the same name exists, it will be replaced
+-- Note: Named handlers are required to support Lua hotreload - when a file is reloaded,
+-- it re-registers its handler with the same name, replacing the old one instead of
+-- creating duplicates
+M.registerOnChangeHandler = function(name, handler)
+  on_change_handlers[name] = handler
+end
+
+-- Start watching a directory for file changes
+M.setup = function(opts)
+  opts = opts or {}
+  local path = opts.path
+  local debounce_delay = opts.debounce or 100 -- ms
+
+  if not path then
+    return false
+  end
+
+  -- Stop existing watcher if any
+  if watcher then
+    M.stop()
+  end
+
+  -- Create fs_event handle
+  local fs_event = uv.new_fs_event()
+  if not fs_event then
+    return false
+  end
+
+  -- Debounced callback for file changes
+  local on_change = debounce(function(err, filename, events)
+    if err then
+      M.stop()
+      return
+    end
+
+    if filename then
+      local full_path = path .. "/" .. filename
+
+      -- Call all registered handlers
+      for _, handler in pairs(on_change_handlers) do
+        pcall(handler, full_path, events)
+      end
+    end
+  end, debounce_delay)
+
+  -- Start watching (wrapped for thread safety)
+  local ok, err = fs_event:start(path, { recursive = false }, vim.schedule_wrap(on_change))
+
+  if ok ~= 0 then
+    return false
+  end
+
+  watcher = fs_event
+  return true
+end
+
+-- Stop the watcher and clean up resources
+M.stop = function()
+  if watcher then
+    watcher:stop()
+    watcher = nil
+  end
+
+  if debounce_timer then
+    debounce_timer:close()
+    debounce_timer = nil
+  end
+end
+
+return M