optimize git with buffering

lua/lib/git.lua

@@ -0,0 +1,93 @@
+local M = {}
+
+local roots = {}
+
+local not_git = 'not a git repo'
+
+local function update_root_status(root)
+  local status = vim.fn.systemlist('cd '..root..' && git status --porcelain=v1')
+  roots[root] = {}
+
+  for _, v in pairs(status) do
+    local head = v:sub(0, 2)
+    local body = v:sub(4, -1)
+    if body:match('%->') ~= nil then
+      body = body:gsub('^.* %-> ', '')
+    end
+    roots[root][body] = head
+  end
+end
+
+function M.reload_roots()
+  for root, status in pairs(roots) do
+    if status ~= not_git then
+      update_root_status(root)
+    end
+  end
+end
+
+local function path_to_matching_str(path)
+  return path:gsub('(%-)', '(%%-)'):gsub('(%.)', '(%%.)')
+end
+
+local function get_git_root(path)
+  if roots[path] then
+    return path, roots[path]
+  end
+
+  for name, status in pairs(roots) do
+    if status ~= not_git then
+      if path:match(path_to_matching_str(name)) then
+        return name, status
+      end
+    end
+  end
+end
+
+local function create_root(cwd)
+  local git_root = vim.fn.system('cd '..cwd..' && git rev-parse --show-toplevel')
+  if not git_root or #git_root == 0 or git_root:match('fatal: not a git repository') then
+    roots[cwd] = not_git
+    return false
+  end
+  update_root_status(git_root:sub(0, -2))
+  return true
+end
+
+function M.update_status(entries, cwd)
+  local git_root, git_status = get_git_root(cwd)
+  if not git_root then
+    if not create_root(cwd) then
+      return
+    end
+    git_root, git_status = get_git_root(cwd)
+  elseif git_status == not_git then
+    return
+  end
+
+  local matching_cwd = path_to_matching_str(git_root..'/')
+  for _, node in pairs(entries) do
+    local relpath = node.absolute_path:gsub(matching_cwd, '')
+    if node.entries ~= nil then
+      relpath = relpath..'/'
+      node.git_status = nil
+    end
+
+    local status = git_status[relpath]
+    if status then
+      node.git_status = status
+    elseif node.entries ~= nil then
+      local matcher = '^'..path_to_matching_str(relpath)
+      for key, _ in pairs(git_status) do
+        if key:match(matcher) then
+          node.git_status = 'dirty'
+          break
+        end
+      end
+    else
+      node.git_status = nil
+    end
+  end
+end
+
+return M