From 027e5234312581efdafa7741603234232e485103 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sindre=20T=2E=20Str=C3=B8m?= <sindrets@gmail.com>
Date: Thu, 22 Apr 2021 21:12:47 +0200
Subject: [PATCH] feat: Sort nodes sensibly (#334)

---
 lua/nvim-tree/populate.lua | 18 ++++++++++
 lua/nvim-tree/utils.lua    | 72 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 89 insertions(+), 1 deletion(-)

diff --git a/lua/nvim-tree/populate.lua b/lua/nvim-tree/populate.lua
index cc9ee881..18f76c74 100644
--- a/lua/nvim-tree/populate.lua
+++ b/lua/nvim-tree/populate.lua
@@ -106,6 +106,16 @@ local function should_group(cwd, dirs, files, links)
   return false
 end
 
+local function node_comparator(a, b)
+  if a.entries and not b.entries then
+    return true
+  elseif not a.entries and b.entries then
+    return false
+  end
+
+  return a.name:lower() <= b.name:lower()
+end
+
 local function gen_ignore_check(cwd)
   if not cwd then cwd = luv.cwd() end
   local ignore_list = {}
@@ -231,12 +241,14 @@ function M.refresh_entries(entries, cwd, parent_node)
 
   local prev = nil
   local change_prev
+  local new_nodes_added = false
   for _, e in ipairs(all) do
     for _, name in ipairs(e.entries) do
       change_prev = true
       if not named_entries[name] then
         local n = e.fn(cwd, name)
         if e.check(n.link_to, n.absolute_path) then
+          new_nodes_added = true
           git.invalidate_gitignore_map(n.absolute_path)
           idx = 1
           if prev then
@@ -258,6 +270,10 @@ function M.refresh_entries(entries, cwd, parent_node)
   if next_node then
     table.insert(entries, 1, next_node)
   end
+
+  if new_nodes_added then
+    utils.merge_sort(entries, node_comparator)
+  end
 end
 
 function M.populate(entries, cwd, parent_node)
@@ -326,6 +342,8 @@ function M.populate(entries, cwd, parent_node)
     return
   end
 
+  utils.merge_sort(entries, node_comparator)
+
   git.update_status(entries, cwd, parent_node)
 end
 
diff --git a/lua/nvim-tree/utils.lua b/lua/nvim-tree/utils.lua
index c09e967e..ab55de53 100644
--- a/lua/nvim-tree/utils.lua
+++ b/lua/nvim-tree/utils.lua
@@ -1,5 +1,5 @@
 local M = {}
-local uv = vim.loop -- or require("luv") ? i dont understand
+local uv = vim.loop
 local api = vim.api
 
 function M.path_to_matching_str(path)
@@ -83,4 +83,74 @@ function M.find_node(nodes, fn)
   return nil, i
 end
 
+---Create a shallow copy of a portion of a list.
+---@param t table
+---@param first integer First index, inclusive
+---@param last integer Last index, inclusive
+---@return table
+function M.tbl_slice(t, first, last)
+  local slice = {}
+  for i = first, last or #t, 1 do
+    table.insert(slice, t[i])
+  end
+
+  return slice
+end
+
+local function merge(t, first, mid, last, comparator)
+  local n1 = mid - first + 1
+  local n2 = last - mid
+  local ls = M.tbl_slice(t, first, mid)
+  local rs = M.tbl_slice(t, mid + 1, last)
+  local i = 1
+  local j = 1
+  local k = first
+
+  while (i <= n1 and j <= n2) do
+    if comparator(ls[i], rs[j]) then
+      t[k] = ls[i]
+      i = i + 1
+    else
+      t[k] = rs[j]
+      j = j + 1
+    end
+    k = k + 1
+  end
+
+  while i <= n1 do
+    t[k] = ls[i]
+    i = i + 1
+    k = k + 1
+  end
+
+  while j <= n2 do
+    t[k] = rs[j]
+    j = j + 1
+    k = k + 1
+  end
+end
+
+local function split_merge(t, first, last, comparator)
+  if (last - first) < 1 then return end
+
+  local mid = math.floor((first + last) / 2)
+
+  split_merge(t, first, mid, comparator)
+  split_merge(t, mid + 1, last, comparator)
+  merge(t, first, mid, last, comparator)
+end
+
+---Perform a merge sort on a given list.
+---@param t any[]
+---@param comparator function|nil
+function M.merge_sort(t, comparator)
+  if not comparator then
+    comparator = function (a, b)
+      return a < b
+    end
+  end
+
+  split_merge(t, 1, #t, comparator)
+end
+
 return M