refacto: rewrite reloader

next step needs to merge the reloader and the explorer, the ancient code
was super complicated and long and the new one is very similar to the explorer.

lua/nvim-tree/explorer/reload.lua

@@ -1,5 +1,5 @@
 local api = vim.api
-local luv = vim.loop
+local uv = vim.loop
 
 local utils = require'nvim-tree.utils'
 local eutils = require'nvim-tree.explorer.utils'
@@ -7,67 +7,60 @@ local builders = require'nvim-tree.explorer.node-builders'
 
 local M = {}
 
+local function key_by(nodes, key)
+  local v = {}
+  for _, node in ipairs(nodes) do
+    v[node[key]] = node
+  end
+  return v
+end
+
 function M.reload(node, cwd, status)
-  local handle = luv.fs_scandir(cwd)
+  local handle = uv.fs_scandir(cwd)
   if type(handle) == 'string' then
     api.nvim_err_writeln(handle)
     return
   end
 
-  local named_nodes = {}
-  local cached_nodes = {}
-  local nodes_idx = {}
-  for i, child in ipairs(node.nodes) do
-    child.git_status = (node and node.git_status == '!!' and '!!')
-      or (status.files and status.files[child.absolute_path])
-      or (status.dirs and status.dirs[child.absolute_path])
-    cached_nodes[i] = child.name
-    nodes_idx[child.name] = i
-    named_nodes[child.name] = child
+  if node.group_next then
+    node.group_next = nil
+    node.nodes = {}
   end
 
-  local dirs = {}
-  local links = {}
-  local files = {}
-  local new_nodes = {}
-  local num_new_nodes = 0
+  local child_names = {}
 
+  local node_ignored = node.git_status == '!!'
+  local nodes_by_path = key_by(node.nodes, "absolute_path")
   while true do
-    local name, t = luv.fs_scandir_next(handle)
+    local name, t = uv.fs_scandir_next(handle)
     if not name then break end
-    num_new_nodes = num_new_nodes + 1
 
     local abs = utils.path_join({cwd, name})
-    if not eutils.should_ignore(abs) and not eutils.should_ignore_git(abs, status.files) then
-      if not t then
-        local stat = luv.fs_stat(abs)
-        t = stat and stat.type
-      end
-
-      if t == 'directory' then
-        table.insert(dirs, name)
-        new_nodes[name] = true
+    t = t or (uv.fs_stat(abs) or {}).type
+    child_names[abs] = true
+    if not nodes_by_path[abs] and not eutils.should_ignore(abs) and not eutils.should_ignore_git(abs, status.files) then
+      if t == 'directory' and uv.fs_access(abs, 'R') then
+        table.insert(node.nodes, builders.folder(abs, name, status, node_ignored))
       elseif t == 'file' then
-        table.insert(files, name)
-        new_nodes[name] = true
+        table.insert(node.nodes, builders.file(abs, name, status, node_ignored))
       elseif t == 'link' then
-        table.insert(links, name)
-        new_nodes[name] = true
+        local link = builders.link(abs, name, status, node_ignored)
+        if link.link_to ~= nil then
+          table.insert(node.nodes, link)
+        end
       end
     end
   end
 
-  -- Handle grouped dirs
-  local child_node = node.group_next
-  if child_node then
-    child_node.open = true
-    if num_new_nodes ~= 1 or not new_nodes[child_node.name] then
-      -- dir is no longer only containing a group dir, or group dir has been removed
-      -- either way: sever the group link on current dir
-      node.nodes = node.group_next
-      node.group_next = nil
-      named_nodes[child_node.name] = child_node
-    else
+  for i, n in ipairs(node.nodes) do
+    if not child_names[n.absolute_path] then
+      table.remove(node.nodes, i)
+    end
+  end
+
+  if vim.g.nvim_tree_group_empty == 1 then
+    local child_node = node.nodes[1]
+    if #(node.nodes) == 1 and child_node.nodes and uv.fs_access(child_node.absolute_path, 'R') then
       node.group_next = child_node
       local ns = M.reload(child_node, child_node.absolute_path, status)
       node.nodes = ns or {}
@@ -75,68 +68,7 @@ function M.reload(node, cwd, status)
     end
   end
 
-  local idx = 1
-  for _, name in ipairs(cached_nodes) do
-    local named_node = named_nodes[name]
-    if named_node and named_node.link_to then
-      -- If the link has been modified: remove it in case the link target has changed.
-      local stat = luv.fs_stat(node.absolute_path)
-      if stat and named_node.last_modified ~= stat.mtime.sec then
-        new_nodes[name] = nil
-        named_nodes[name] = nil
-      end
-    end
-
-    if not new_nodes[name] then
-      table.remove(node.nodes, idx)
-    else
-      idx = idx + 1
-    end
-  end
-
-  local all = {
-    { nodes = dirs, fn = builders.folder, check = function(_, abs) return luv.fs_access(abs, 'R') end },
-    { nodes = links, fn = builders.link, check = function(name) return name ~= nil end },
-    { nodes = files, fn = builders.file, check = function() return true end }
-  }
-
-  local prev = nil
-  local change_prev
-  local new_nodes_added = false
-  local parent_ignored = node.git_status == '!!'
-  for _, e in ipairs(all) do
-    for _, name in ipairs(e.nodes) do
-      change_prev = true
-      if not named_nodes[name] then
-        local abs = utils.path_join({cwd, name})
-        local n = e.fn(abs, name, status, parent_ignored)
-        if e.check(n.link_to, n.absolute_path) then
-          new_nodes_added = true
-          idx = 1
-          if prev then
-            idx = nodes_idx[prev] + 1
-          end
-          table.insert(node.nodes, idx, n)
-          nodes_idx[name] = idx
-          cached_nodes[idx] = name
-        else
-          change_prev = false
-        end
-      end
-      if change_prev and not (child_node and child_node.name == name) then
-        prev = name
-      end
-    end
-  end
-
-  if child_node then
-    table.insert(node.nodes, 1, child_node)
-  end
-
-  if new_nodes_added then
-    utils.merge_sort(node.nodes, eutils.node_comparator)
-  end
-
+  utils.merge_sort(node.nodes, eutils.node_comparator)
   return node.nodes
 end