From 5c451ff0f2f8e6aa2c0b47e5439bf2e459ccf37a Mon Sep 17 00:00:00 2001
From: Grzegorz Milka <grzegorzmilka@gmail.com>
Date: Wed, 15 Mar 2023 19:11:26 +0100
Subject: [PATCH] feat: add max_traversed_entries option

At my work, we have a huge monorepo with a directory with over 70k
entries. This plugin, being synchronous, was blocking Neovim for tens of
seconds.

This option should be universally useful to just time-box any search
done by this plugin. I don't think it makes sense to leave this
search unbounded as people expect interactivity from Neovim.

Perhaps, some change of API will make it possible to make search more
optimal (e.g., a batch fetch), but even than a limit to how many entries
Neovim has to process is relevant.
---
 README.md             | 10 ++++++++++
 lua/cmp_path/init.lua |  7 ++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 1cfd7a6..a5d33da 100644
--- a/README.md
+++ b/README.md
@@ -48,3 +48,13 @@ Specify if directory names in the completion menu should include a trailing slas
 _Default:_ returns the current working directory of the current buffer
 
 Specifies the base directory for relative paths.
+
+### max_traverse_entries (type: number)
+
+_Default:_ `nil`
+
+The maximum count of entries in a directory will this source traverse before returning candidates.
+
+Some directories may have a large number of entries. Users, who prefer to have a time-bounded feedback over completeness, may limit the number of entries this plugin fetches with this option.
+
+If this option is set to nil, there's no effective limit.
diff --git a/lua/cmp_path/init.lua b/lua/cmp_path/init.lua
index 4e63d27..86ed495 100644
--- a/lua/cmp_path/init.lua
+++ b/lua/cmp_path/init.lua
@@ -13,6 +13,7 @@ local constants = {
 ---@field public trailing_slash boolean
 ---@field public label_trailing_slash boolean
 ---@field public get_cwd fun(): string
+---@field public max_traversed_entries number
 
 ---@type cmp_path.Option
 local defaults = {
@@ -21,6 +22,7 @@ local defaults = {
   get_cwd = function(params)
     return vim.fn.expand(('#%d:p:h'):format(params.context.bufnr))
   end,
+  max_traversed_entries = nil,
 }
 
 source.new = function()
@@ -168,7 +170,8 @@ source._candidates = function(_, dirname, include_hidden, option, callback)
     table.insert(items, item)
   end
 
-  while true do
+  local entry_count = 0
+  while option.max_traversed_entries == nil or entry_count < option.max_traversed_entries do
     local name, fs_type, e = vim.loop.fs_scandir_next(fs)
     if e then
       return callback(fs_type, nil)
@@ -177,6 +180,7 @@ source._candidates = function(_, dirname, include_hidden, option, callback)
       break
     end
     create_item(name, fs_type)
+    entry_count = entry_count + 1
   end
 
   callback(nil, items)
@@ -198,6 +202,7 @@ source._validate_option = function(_, params)
     trailing_slash = { option.trailing_slash, 'boolean' },
     label_trailing_slash = { option.label_trailing_slash, 'boolean' },
     get_cwd = { option.get_cwd, 'function' },
+    max_traversed_entries = { option.max_traversed_entries, { 'number', 'nil' }},
   })
   return option
 end