feat(event): add WillCreateFile, WillRemoveFile (#2273)

node. These are mostly going to be useful for implementing lsp file
operation actions.

Co-authored-by: Alexander Courtis <alex@courtis.org>

doc/nvim-tree-lua.txt

@@ -2186,10 +2186,20 @@ e.g. handler for node renamed: >
                 handler parameters: ~
                   {fname}        `{string}` Absolute path to the created file
 
+- Event.WillCreateFile
+                handler parameters: ~
+                  {fname}        `{string}` Absolute path to the file to be
+                  created
+
 - Event.FileRemoved
                 handler parameters: ~
                   {fname}        `{string}` Absolute path to the removed file.
 
+- Event.WillRemoveFile
+                handler parameters: ~
+                  {fname}        `{string}` Absolute path to the file to be
+                  removed
+
 - Event.FolderCreated
                 handler parameters: ~
                   {folder_name}  `{string}` Absolute path to the created folder.

lua/nvim-tree/actions/fs/create-file.lua

@@ -9,6 +9,7 @@ local find_file = require("nvim-tree.actions.finders.find-file").fn
 local M = {}
 
 local function create_and_notify(file)
+  events._dispatch_will_create_file(file)
   local ok, fd = pcall(vim.loop.fs_open, file, "w", 420)
   if not ok then
     notify.error("Couldn't create file " .. file)

lua/nvim-tree/actions/fs/remove-file.lua

@@ -81,6 +81,7 @@ function M.remove(node)
     end
     events._dispatch_folder_removed(node.absolute_path)
   else
+    events._dispatch_will_remove_file(node.absolute_path)
     local success = vim.loop.fs_unlink(node.absolute_path)
     if not success then
       return notify.error("Could not remove " .. node.name)

lua/nvim-tree/actions/fs/trash.lua

@@ -75,6 +75,7 @@ function M.fn(node)
         end
       end)
     else
+      events._dispatch_will_remove_file(node.absolute_path)
       trash_path(function(_, rc)
         if rc ~= 0 then
           notify.warn("trash failed: " .. err_msg .. "; please see :help nvim-tree.trash")

lua/nvim-tree/events.lua

@@ -10,7 +10,9 @@ M.Event = {
   NodeRenamed = "NodeRenamed",
   TreeOpen = "TreeOpen",
   TreeClose = "TreeClose",
+  WillCreateFile = "WillCreateFile",
   FileCreated = "FileCreated",
+  WillRemoveFile = "WillRemoveFile",
   FileRemoved = "FileRemoved",
   FolderCreated = "FolderCreated",
   FolderRemoved = "FolderRemoved",
@@ -52,11 +54,21 @@ function M._dispatch_node_renamed(old_name, new_name)
   dispatch(M.Event.NodeRenamed, { old_name = old_name, new_name = new_name })
 end
 
+--@private
+function M._dispatch_will_remove_file(fname)
+  dispatch(M.Event.WillRemoveFile, { fname = fname })
+end
+
 --@private
 function M._dispatch_file_removed(fname)
   dispatch(M.Event.FileRemoved, { fname = fname })
 end
 
+--@private
+function M._dispatch_will_create_file(fname)
+  dispatch(M.Event.WillCreateFile, { fname = fname })
+end
+
 --@private
 function M._dispatch_file_created(fname)
   dispatch(M.Event.FileCreated, { fname = fname })