Persist scratch buffer across sessions

- Adds doom/open-project-scratch-buffer (persistent project scratch
  buffers)
- Prefix arg = open scratch buffer in current window, for both
  doom/open-scratch-buffer and doom/open-project-scratch-buffer.
- Rename doom/delete-scratch-files ->
  doom/delete-persistent-scratch-file
- Remove doom-scratch-buffer-display-fn
- Rename doom-scratch-files-dir -> doom-scratch-dir
- Add SPC p s keybind to open project scratch buffer

core/autoload/scratch.el

@@ -1,12 +1,12 @@
 ;;; core/autoload/scratch.el -*- lexical-binding: t; -*-
 
-(defvar doom-scratch-files-dir (concat doom-etc-dir "scratch/")
+(defvar doom-scratch-default-file "__default"
-  "Where to store project scratch files, created by
+  "The default file name for a project-less scratch buffer.
-`doom/open-project-scratch-buffer'.")
 
-(defvar doom-scratch-buffer-display-fn #'display-buffer
+Will be saved in `doom-scratch-dir'.")
-  "The function to use to display the scratch buffer. Must accept one argument:
+
-the buffer to display.")
+(defvar doom-scratch-dir (concat doom-etc-dir "scratch")
+  "Where to save persistent scratch buffers.")
 
 (defvar doom-scratch-buffer-major-mode nil
   "What major mode to use in scratch buffers. This can be one of the
@@ -16,77 +16,129 @@ following:
   nil         Uses `fundamental-mode'
   MAJOR-MODE  Any major mode symbol")
 
+(defvar doom-scratch-buffers nil
+  "A list of active scratch buffers.")
+
+(defvar-local doom-scratch-current-project nil
+  "The name of the project associated with the current scratch buffer.")
+
 (defvar doom-scratch-buffer-hook ()
-  "The hooks to run after a scratch buffer is made.")
+  "The hooks to run after a scratch buffer is created.")
+
+(defun doom--load-persistent-scratch-buffer (name)
+  (let ((scratch-file (expand-file-name (or name doom-scratch-default-file)
+                                        doom-scratch-dir)))
+    (make-directory doom-scratch-dir t)
+    (if (not (file-readable-p scratch-file))
+        nil
+      (erase-buffer)
+      (insert-file-contents scratch-file)
+      (set-auto-mode)
+      t)))
+
+;;;###autoload
+(defun doom-scratch-buffer (&optional mode directory project-name)
+  "Return a scratchpad buffer in major MODE."
+  (let* ((buffer-name (if project-name
+                          (format "*doom:scratch (%s)*" project-name)
+                        "*doom:scratch*"))
+         (buffer (get-buffer buffer-name)))
+    (with-current-buffer (get-buffer-create buffer-name)
+      (unless buffer
+        (setq buffer (current-buffer)
+              default-directory directory
+              doom-scratch-current-project project-name)
+        (setq doom-scratch-buffers (cl-delete-if-not #'buffer-live-p doom-scratch-buffers))
+        (cl-pushnew buffer doom-scratch-buffers)
+        (doom--load-persistent-scratch-buffer project-name)
+        (when (and (eq major-mode 'fundamental-mode)
+                   (functionp mode))
+          (funcall mode))
+        (add-hook 'kill-buffer-hook #'doom|persist-scratch-buffer nil 'local)
+        (run-hooks 'doom-scratch-buffer-created-hook))
+      buffer)))
 
 
 ;;
-;; Library
+;;; Persistent scratch buffer
 
 ;;;###autoload
-(defun doom-scratch-buffer (&optional file mode text)
+(defun doom|persist-scratch-buffer ()
-  "Return a scratchpad buffer in major MODE with TEXT in it.
+  "Save the current buffer to `doom-scratch-dir'."
+  (write-region
+   (point-min) (point-max)
+   (expand-file-name (or doom-scratch-current-project doom-scratch-default-file)
+                     doom-scratch-dir)))
 
-If FILE is a valid path, open it as if it were a persistent scratchpad."
+;;;###autoload
-  (if file (setq file (file-truename file)))
+(defun doom|persist-scratch-buffers ()
-  (let ((buffer
+  "Save all scratch buffers to `doom-scratch-dir'."
-         (if file
+  (dolist (buffer (cl-delete-if-not #'buffer-live-p doom-scratch-buffers))
-             (with-current-buffer (find-file-noselect file)
-               (rename-buffer (format "*doom:scratch (%s)*" (file-name-nondirectory file)))
-               (current-buffer))
-           (get-buffer-create "*doom:scratch*"))))
     (with-current-buffer buffer
-      (when (and (functionp mode)
+      (doom|persist-scratch-buffer))))
-                 (not (eq major-mode mode)))
-        (funcall mode))
-      (when text
-        (insert text))
-      (run-hooks 'doom-scratch-buffer-hook)
-      (current-buffer))))
 
 ;;;###autoload
-(defun doom/open-scratch-buffer (&optional arg)
+(add-hook 'kill-emacs-hook #'doom|persist-scratch-buffers)
-  "Opens a scratch pad window in the same major-mode.
 
-If ARG (universal argument), then open a persistent scratch pad buffer. You'll
-be prompted for its name, or to open a previously created. These are stored in
-`doom-scratch-files-dir'.
 
-If a region is active, copy its contents to the scratch pad."
+;;
+;;; Commands
+
+;;;###autoload
+(defun doom/open-scratch-buffer (&optional arg project-p)
+  "Opens the (persistent) scratch buffer in a popup.
+
+If ARG, switch to it in the current window."
   (interactive "P")
   (let (projectile-enable-caching)
     (funcall
-     doom-scratch-buffer-display-fn
+     (if arg
+         #'switch-to-buffer
+       #'pop-to-buffer)
      (doom-scratch-buffer
-      (when arg
-        (if-let* ((file (read-file-name "Open scratch file > " doom-scratch-files-dir "scratch")))
-            file
-          (user-error "Aborting")))
       (cond ((eq doom-scratch-buffer-major-mode t)
              (unless (or buffer-read-only
                          (derived-mode-p 'special-mode)
                          (string-match-p "^ ?\\*" (buffer-name)))
                major-mode))
-            ((null doom-scratch-buffer-major-mode) nil)
+            ((null doom-scratch-buffer-major-mode)
+             nil)
             ((symbolp doom-scratch-buffer-major-mode)
              doom-scratch-buffer-major-mode))
-      (and (region-active-p)
+      default-directory
-           (buffer-substring-no-properties
+      (when project-p
-            (region-beginning) (region-end)))))))
+        (doom-project-name))))))
 
 ;;;###autoload
-(defun doom/switch-to-scratch-buffer (&optional arg)
+(defun doom/open-project-scratch-buffer (&optional arg)
-  "Switches to a scratch pad buffer in the current window.
+  "Opens the (persistent) project scratch buffer in a popup.
 
-Otherwise, does exactly what `doom/open-scratch-buffer' does."
+If ARG, switch to it in the current window."
   (interactive "P")
-  (let ((doom-scratch-buffer-display-fn #'switch-to-buffer))
+  (doom/open-scratch-buffer arg 'project))
-    (doom/open-scratch-buffer arg)))
 
 ;;;###autoload
-(defun doom/delete-scratch-files ()
+(defun doom/revert-scratch-buffer ()
-  "Deletes all scratch buffers in `doom-scratch-files-dir'."
+  "Revert scratch buffer to last persistent state."
   (interactive)
-  (dolist (file (directory-files doom-scratch-files-dir t "^[^.]" t))
+  (unless (string-match-p "^\\*doom:scratch" (buffer-name))
-    (delete-file file)
+    (user-error "Not in a scratch buffer"))
-    (message "Deleted '%s'" (file-name-nondirectory file))))
+  (when (doom--load-persistent-scratch-buffer doom-scratch-current-project)
+    (message "Reloaded scratch buffer")))
+
+;;;###autoload
+(defun doom/delete-persistent-scratch-file (&optional arg)
+  "Deletes a scratch buffer file in `doom-scratch-dir'.
+
+If prefix ARG, delete all persistent scratches."
+  (interactive)
+  (if arg
+      (progn
+        (delete-directory doom-scratch-dir t)
+        (message "Cleared %S" (abbreviate-file-name doom-scratch-dir)))
+    (make-directory doom-scratch-dir t)
+    (let ((file (read-file-name "Delete scratch file > " doom-scratch-dir "scratch")))
+      (if (not (file-exists-p file))
+          (message "%S does not exist" (abbreviate-file-name file))
+        (delete-file file)
+        (message "Successfully deleted %S" (abbreviate-file-name file))))))

modules/config/default/+evil-bindings.el

@@ -735,6 +735,7 @@
         :desc "Find other file"              "o" #'projectile-find-other-file
         :desc "Switch project"               "p" #'projectile-switch-project
         :desc "Find recent project files"    "r" #'projectile-recentf
+        :desc "Scratch buffer"               "s" #'doom/open-project-scratch-buffer
         :desc "List project tasks"           "t" #'+default/project-tasks
         (:prefix ("x" . "terminal")
           :desc "Open eshell in project"     "e" #'projectile-run-eshell

modules/ui/popup/config.el

@@ -136,7 +136,7 @@ prevent the popup(s) from messing up the UI (or vice versa)."
        :slot -1 :vslot -2 :ttl 0)
       ("^\\*Compil\\(?:ation\\|e-Log\\)"
        :vslot -2 :size 0.3 :ttl nil :quit t)
-      ("^\\*\\(?:\\(?:doom:\\)?scratch\\|Messages\\)"
+      ("^\\*\\(?:scratch\\|Messages\\)"
        :autosave t :ttl nil)
       ("^\\*Man "
        :size 0.45 :vslot -3 :ttl 0 :quit t :select t)