feat: extensions can support special windows

README.md

@@ -10,14 +10,13 @@ A: All the other plugins use `:mksession` under the hood
 
 **Q: Why don't you want to use `:mksession`?**
 
-A: While it's amazing that this feature is built-in to vim, and it does an impressively good job for most situations, it's very difficult to customize. If `:help sessionoptions` covers your use case, then you're golden. If you want anything else, you're out of luck.
+A: While it's amazing that this feature is built-in to vim, and it does an impressively good job for most situations, it is very difficult to customize. If `:help sessionoptions` covers your use case, then you're golden. If you want anything else, you're out of luck.
 
 ## TODO
 
 - [ ] tab-scoped sessions
 - [ ] documentation
 - [ ] make filepaths relative so sessions are portable
-- [ ] extensions can add supported buffers (e.g. nvim-tree, aerial)
 
 ## Requirements
 

lua/resession/extensions/example.lua

@@ -0,0 +1,44 @@
+local M = {}
+
+---Get the saved data for this extension
+---@return any
+M.on_save = function()
+  return {}
+end
+
+M.on_load = function(data)
+  --
+end
+
+---Called when resession gets configured
+---This function is optional
+---@param data table The configuration data passed in the config
+M.config = function(data)
+  --
+end
+
+---Check if a window is supported by this extension
+---This function is optional for extensions
+---@param winid integer
+---@param bufnr integer
+---@return boolean
+M.is_win_supported = function(winid, bufnr)
+  return true
+end
+
+---Save data for a window
+---@param winid integer
+---@return any
+M.save_win = function(winid)
+  return {}
+end
+
+---Called with the data from save_win
+---@param winid integer
+---@param config any
+---@return integer|nil If the original window has been replaced, return the new ID that should replace it
+M.load_win = function(winid, config)
+  --
+end
+
+return M

lua/resession/layout.lua

@@ -7,17 +7,36 @@ local M = {}
 ---@return table|false
 M.get_win_info = function(tabnr, winid)
   local bufnr = vim.api.nvim_win_get_buf(winid)
-  if not config.buffers.filter(bufnr) then
+  local win = {}
+  local supported_by_ext = false
+  for ext_name in pairs(config.extensions) do
+    local ext = util.get_extension(ext_name)
+    if ext and ext.is_win_supported and ext.is_win_supported(winid, bufnr) then
+      local ok, extension_data = pcall(ext.save_win, winid)
+      if ok then
+        win.extension_data = extension_data
+        win.extension = ext_name
+        supported_by_ext = true
+      else
+        vim.notify(
+          string.format("[resession] Extension %s save_win error: %s", ext_name, extension_data),
+          vim.log.levels.ERROR
+        )
+      end
+      break
+    end
+  end
+  if not supported_by_ext and not config.buffers.filter(bufnr) then
     return false
   end
-  local win = {
+  win = vim.tbl_extend("error", win, {
     bufname = vim.api.nvim_buf_get_name(bufnr),
     current = vim.api.nvim_get_current_win() == winid,
     cursor = vim.api.nvim_win_get_cursor(winid),
     width = vim.api.nvim_win_get_width(winid),
     height = vim.api.nvim_win_get_height(winid),
     options = util.save_win_options(winid),
-  }
+  })
   local winnr = vim.api.nvim_win_get_number(winid)
   if vim.fn.haslocaldir(winnr, tabnr) == 1 then
     win.cwd = vim.fn.getcwd(winnr, tabnr)
@@ -56,17 +75,14 @@ M.add_win_info_to_layout = function(tabnr, layout)
   return layout
 end
 
-local function set_winlayout(layout, visit_data)
+local function set_winlayout(layout)
   local type = layout[1]
   if type == "leaf" then
     local win = layout[2]
     win.winid = vim.api.nvim_get_current_win()
     if win.cwd then
       vim.cmd(string.format("lcd %s", win.cwd))
     end
-    if win.current then
-      visit_data.winid = vim.api.nvim_get_current_win()
-    end
   else
     local winids = {}
     for i, v in ipairs(layout[2]) do
@@ -81,7 +97,7 @@ local function set_winlayout(layout, visit_data)
     end
     for i, v in ipairs(layout[2]) do
       vim.api.nvim_set_current_win(winids[i])
-      set_winlayout(v, visit_data)
+      set_winlayout(v)
     end
   end
 end
@@ -95,24 +111,42 @@ end
 
 ---@param layout table
 ---@param scale_factor number[] Scaling factor for [width, height]
-local function set_winlayout_data(layout, scale_factor)
+local function set_winlayout_data(layout, scale_factor, visit_data)
   local type = layout[1]
   if type == "leaf" then
     local win = layout[2]
-    local bufnr = vim.fn.bufadd(win.bufname)
-    vim.api.nvim_win_set_buf(win.winid, bufnr)
-    -- After setting the buffer into the window, manually set the filetype to trigger syntax
-    -- highlighting
-    vim.api.nvim_buf_set_option(bufnr, "filetype", vim.api.nvim_buf_get_option(bufnr, "filetype"))
-    vim.api.nvim_win_set_cursor(win.winid, win.cursor)
+    if win.extension then
+      local ext = util.get_extension(win.extension)
+      if ext then
+        local ok, new_winid = pcall(ext.load_win, win.winid, win.extension_data)
+        if ok then
+          win.winid = new_winid or win.winid
+        else
+          vim.notify(
+            string.format("[resession] Extension %s load_win error: %s", win.extension, new_winid),
+            vim.log.levels.ERROR
+          )
+        end
+      end
+    else
+      local bufnr = vim.fn.bufadd(win.bufname)
+      vim.api.nvim_win_set_buf(win.winid, bufnr)
+      -- After setting the buffer into the window, manually set the filetype to trigger syntax
+      -- highlighting
+      vim.api.nvim_buf_set_option(bufnr, "filetype", vim.api.nvim_buf_get_option(bufnr, "filetype"))
+    end
+    pcall(vim.api.nvim_win_set_cursor, win.winid, win.cursor)
     util.restore_win_options(win.winid, win.options)
-    local width_scale = vim.wo[win.winid].winfixwidth and 1 or scale_factor[1]
+    local width_scale = vim.wo.winfixwidth and 1 or scale_factor[1]
     vim.api.nvim_win_set_width(win.winid, scale(win.width, width_scale))
-    local height_scale = vim.wo[win.winid].winfixheight and 1 or scale_factor[2]
+    local height_scale = vim.wo.winfixheight and 1 or scale_factor[2]
     vim.api.nvim_win_set_height(win.winid, scale(win.height, height_scale))
+    if win.current then
+      visit_data.winid = win.winid
+    end
   else
     for i, v in ipairs(layout[2]) do
-      set_winlayout_data(v, scale_factor)
+      set_winlayout_data(v, scale_factor, visit_data)
     end
   end
 end
@@ -121,9 +155,9 @@ end
 ---@param scale_factor number[] Scaling factor for [width, height]
 ---@return nil|integer The window that should have focus after session load
 M.set_winlayout = function(layout, scale_factor)
+  set_winlayout(layout)
   local ret = {}
-  set_winlayout(layout, ret)
-  set_winlayout_data(layout, scale_factor)
+  set_winlayout_data(layout, scale_factor, ret)
   return ret.winid
 end