add event API (#265)

lua/nvim-tree/events.lua

@@ -0,0 +1,94 @@
+local M = {}
+
+local global_handlers = {}
+
+local Event = {
+  NodeRenamed = 'NodeRenamed',
+  FileCreated = 'FileCreated',
+  FileRemoved = 'FileRemoved',
+  FolderCreated = 'FolderCreated',
+  FolderRemoved = 'FolderRemoved',
+}
+
+local function get_handlers(event_name)
+  return global_handlers[event_name] or {}
+end
+
+local function register_handler(event_name, handler)
+  local handlers = get_handlers(event_name)
+  table.insert(handlers, handler)
+  global_handlers[event_name] = handlers
+end
+
+
+local function dispatch(event_name, payload)
+  for _, handler in pairs(get_handlers(event_name)) do
+    local success, error = pcall(handler, payload)
+    if not success then
+      vim.api.nvim_err_writeln('Handler for event ' .. event_name .. ' errored. ' .. vim.inspect(error))
+    end
+  end
+end
+
+--@private
+function M._dispatch_node_renamed(old_name, new_name)
+  dispatch(Event.NodeRenamed, {old_name=old_name, new_name=new_name})
+end
+
+--@private
+function M._dispatch_file_removed(fname)
+  dispatch(Event.FileRemoved, {fname=fname})
+end
+
+--@private
+function M._dispatch_file_created(fname)
+  dispatch(Event.FileCreated, {fname=fname})
+end
+
+--@private
+function M._dispatch_folder_created(folder_name)
+  dispatch(Event.FolderCreated, {folder_name=folder_name})
+end
+
+--@private
+function M._dispatch_folder_removed(folder_name)
+  dispatch(Event.FolderRemoved, {folder_name=folder_name})
+end
+
+--Registers a handler for the NodeRenamed event.
+--@param handler (function) Handler with the signature function(payload), where payload is a table containing:
+--  - old_name (string) Absolute path to the old node location.
+--  - new_name (string) Absolute path to the new node location.
+function M.on_node_renamed(handler)
+  register_handler(Event.NodeRenamed, handler)
+end
+
+--Registers a handler for the FileCreated event.
+--@param handler (function) Handler with the signature function(payload), where payload is a table containing:
+--  - fname (string) Absolute path to the created file.
+function M.on_file_created(handler)
+  register_handler(Event.FileCreated, handler)
+end
+
+--Registers a handler for the FileRemoved event.
+--@param handler (function) Handler with the signature function(payload), where payload is a table containing:
+--  - fname (string) Absolute path to the removed file.
+function M.on_file_removed(handler)
+  register_handler(Event.FileRemoved, handler)
+end
+
+--Registers a handler for the FolderCreated event.
+--@param handler (function) Handler with the signature function(payload), where payload is a table containing:
+--  - folder_name (string) Absolute path to the created folder.
+function M.on_folder_created(handler)
+  register_handler(Event.FolderCreated, handler)
+end
+
+--Registers a handler for the FolderRemoved event.
+--@param handler (function) Handler with the signature function(payload), where payload is a table containing:
+--  - folder_name (string) Absolute path to the removed folder.
+function M.on_folder_removed(handler)
+  register_handler(Event.FolderRemoved, handler)
+end
+
+return M