feat(explorer): add filesystem watchers (#1304)

* feat(explorer): add experimental watchers

This commit introduces watchers to update the tree.
This behavior is introduced behind an "filesystem_watchers" option
which should prevent instabilities.
It will become the default at some point.

Co-authored-by: Alexander Courtis <alex@courtis.org>

lua/nvim-tree/git/init.lua

@@ -1,5 +1,8 @@
+local log = require "nvim-tree.log"
+local utils = require "nvim-tree.utils"
 local git_utils = require "nvim-tree.git.utils"
 local Runner = require "nvim-tree.git.runner"
+local Watcher = require("nvim-tree.watcher").Watcher
 
 local M = {
   config = nil,
@@ -13,22 +16,37 @@ function M.reload()
   end
 
   for project_root in pairs(M.projects) do
-    M.projects[project_root] = {}
-    local git_status = Runner.run {
-      project_root = project_root,
-      list_untracked = git_utils.should_show_untracked(project_root),
-      list_ignored = true,
-      timeout = M.config.timeout,
-    }
-    M.projects[project_root] = {
-      files = git_status,
-      dirs = git_utils.file_status_to_dir_status(git_status, project_root),
-    }
+    M.reload_project(project_root)
   end
 
   return M.projects
 end
 
+function M.reload_project(project_root)
+  local project = M.projects[project_root]
+  if not project or not M.config.enable then
+    return
+  end
+
+  local watcher = M.projects[project_root].watcher
+  M.projects[project_root] = {}
+  local git_status = Runner.run {
+    project_root = project_root,
+    list_untracked = git_utils.should_show_untracked(project_root),
+    list_ignored = true,
+    timeout = M.config.timeout,
+  }
+  M.projects[project_root] = {
+    files = git_status,
+    dirs = git_utils.file_status_to_dir_status(git_status, project_root),
+    watcher = watcher,
+  }
+end
+
+function M.get_project(project_root)
+  return M.projects[project_root]
+end
+
 function M.get_project_root(cwd)
   if M.cwd_to_project_root[cwd] then
     return M.cwd_to_project_root[cwd]
@@ -42,6 +60,35 @@ function M.get_project_root(cwd)
   return project_root
 end
 
+function M.reload_tree_at(project_root)
+  local root_node = utils.get_node_from_path(project_root)
+  if not root_node then
+    return
+  end
+
+  M.reload_project(project_root)
+  local project = M.get_project(project_root)
+
+  local project_files = project.files and project.files or {}
+  local project_dirs = project.dirs and project.dirs or {}
+
+  local function iterate(n)
+    local parent_ignored = n.git_status == "!!"
+    for _, node in pairs(n.nodes) do
+      node.git_status = project_dirs[node.absolute_path] or project_files[node.absolute_path]
+      if not node.git_status and parent_ignored then
+        node.git_status = "!!"
+      end
+
+      if node.nodes and #node.nodes > 0 then
+        iterate(node)
+      end
+    end
+  end
+
+  iterate(root_node)
+end
+
 function M.load_project_status(cwd)
   if not M.config.enable then
     return {}
@@ -64,15 +111,32 @@ function M.load_project_status(cwd)
     list_ignored = true,
     timeout = M.config.timeout,
   }
+
+  local watcher = nil
+  if M.config.watcher.enable then
+    log.line("watcher", "git start")
+    watcher = Watcher.new {
+      absolute_path = utils.path_join { project_root, ".git" },
+      interval = M.config.watcher.interval,
+      on_event = function()
+        log.line("watcher", "git event")
+        M.reload_tree_at(project_root)
+        require("nvim-tree.renderer").draw()
+      end,
+    }
+  end
+
   M.projects[project_root] = {
     files = git_status,
     dirs = git_utils.file_status_to_dir_status(git_status, project_root),
+    watcher = watcher,
   }
   return M.projects[project_root]
 end
 
 function M.setup(opts)
   M.config = opts.git
+  M.config.watcher = opts.filesystem_watchers
 end
 
 return M

lua/nvim-tree/git/runner.lua

@@ -53,7 +53,9 @@ end
 
 function Runner:_log_raw_output(output)
   if output and type(output) == "string" then
-    log.raw("git", "%s", output)
+    -- TODO put this back after watcher feature completed
+    -- log.raw("git", "%s", output)
+    log.line("git", "done")
   end
 end