Don’t err in pip-frame-remove-buffer if there is no PIP frame

This is useful e.g. to prevent the error when a PIP frame with a
temporarily displayed buffer is deleted before the buffer timer
attempts to remove the buffer.

.gitignore

@@ -0,0 +1,2 @@
+*.elc
+*.eld

README.org

@@ -43,6 +43,26 @@ this utility:
 
 * How?
 
+** Installation
+
+You can install pip-frame.el from [[https://melpa.org/#/pip-frame][MELPA]].  If you use [[https://github.com/radian-software/straight.el][straight.el]] and
+prefer using source repos directly, you can install pip-frame.el as
+follows:
+
+   #+begin_src elisp
+(straight-use-package
+ '(pip-frame :type git
+             :repo "https://git.zamazal.org/pdm/pip-frame"
+             :local-repo "pip-frame"))
+   #+end_src
+
+For manual installation, simply put [[./pip-frame.el][pip-frame.el]] file to your
+=site-lisp= directory and add the following to your Emacs configuration:
+
+   #+begin_src elisp
+(require ’pip-frame)
+   #+end_src
+
 ** Commands
 
 The PIP frame is created using =M-x pip-frame-add-buffer= command.  You
@@ -96,6 +116,10 @@ Some customization examples:
                                          (internal-border-width . 20))))
   #+end_src
 
------
+* Contact
 
-/To Petr./
+pip-frame.el is available at [[https://git.zamazal.org/pdm/pip-frame][git.zamazal.org]].  You can file issues
+there.
+
+If you don’t want to discuss things publicly or to bother registering
+at yet another web site, you can reach me at [[mailto:pdm@zamazal.org][pdm@zamazal.org]].

pip-frame.el

@@ -1,7 +1,13 @@
-;;; pip-frame.el --- PIP frame support  -*- lexical-binding: t -*-
+;;; pip-frame.el --- Display and manage a PIP frame  -*- lexical-binding: t -*-
 
 ;; Copyright (C) 2022 Milan Zamazal <pdm@zamazal.org>
 
+;; Author: Milan Zamazal <pdm@zamazal.org>
+;; Version: 1
+;; Package-Requires: ((emacs "25.1"))
+;; Keywords: frames
+;; URL: https://git.zamazal.org/pdm/pip-frame
+
 ;; COPYRIGHT NOTICE
 ;;
 ;; This program is free software: you can redistribute it and/or modify
@@ -17,6 +23,8 @@
 ;; You should have received a copy of the GNU General Public License
 ;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;
 ;; Display a floating Emacs frame with selected buffers.
 ;; Similar to PIP on screens.  Probably most useful in EXWM.
 ;;
@@ -25,10 +33,13 @@
 ;; `M-x pip-frame-remove-buffer' or close the whole frame with
 ;; `M-x pip-frame-delete-frame'.
 
+;;; Code:
+
 (require 'cl-lib)
 
 (defgroup pip-frame ()
-  "Display PIP frame.")
+  "Display PIP frame."
+  :group 'frames)
 
 (defcustom pip-frame-scale 4
   "How many times to shrink the PIP frame relative to the display size."
@@ -49,7 +60,9 @@ Usually, the value should be larger than 0 and much smaller than 1."
 
 (defcustom pip-frame-parameters
   '((left . 0.9)
-    (top .  0.9))
+    (top .  0.9)
+    (tab-bar-lines . 0)
+    (minibuffer . nil))
   "Alist of frame parameters to use for the PIP frame.
 The frame size is determined automatically using `pip-frame-scale'
 custom option but it can be overriden here."
@@ -61,16 +74,21 @@ custom option but it can be overriden here."
   :type '(alist :key-type symbol :value-type sexp)
   :group 'pip-frame)
 
+(defcustom pip-frame-temporary-buffer-seconds 10
+  "Number of seconds to keep a buffer displayed temporarily by default."
+  :type 'number
+  :group 'pip-frame)
+
 (defvar pip-frame--name "PIP-frame")
 
 (defun pip-frame--get-frame (&optional no-error)
   (let ((frame (cl-find pip-frame--name (frame-list)
-                        :key #'(lambda (f) (frame-parameter f 'name)))))
+                        :key (lambda (f) (frame-parameter f 'name)))))
     (or frame
         (unless no-error
           (error "No PIP frame")))))
 
-(defun pip-frame--make-frame ()
+(defun pip-frame--make-frame (buffer)
   (let ((frame (make-frame `((name . ,pip-frame--name)
                              (unsplittable . t)
                              ,@pip-frame-parameters
@@ -79,54 +97,93 @@ custom option but it can be overriden here."
         (frame-inhibit-implied-resize t)
         (face-height (round (/ (face-attribute 'default :height) pip-frame-font-scale))))
     (set-face-attribute 'default frame :height face-height)
-    (mapc #'(lambda (p) (set-face-attribute 'default frame (car p) (cdr p)))
-          pip-frame-face-attributes)
+    (dolist (p pip-frame-face-attributes)
+      (set-face-attribute 'default frame (car p) (cdr p)))
+    (set-window-buffer (car (window-list frame)) buffer)
     frame))
 
 (defun pip-frame-delete-frame ()
-  ""
+  "Delete the PIP frame."
   (interactive)
   (delete-frame (pip-frame--get-frame)))
 
 (defun pip-frame--buffers ()
   (mapcar #'window-buffer (window-list (pip-frame--get-frame))))
 
-(defun pip-frame--add-additional-buffer ()
-  (let* ((windows (window-list (pip-frame--get-frame)))
-         (sizes (mapcar #'(lambda (w)
-                            (let ((width (window-body-width w t))
-                                  (height (window-body-height w t)))
-                              (cons (+ (* width width) (* height height))
-                                    w)))
-                        windows))
-         (largest (cdr (cl-first (cl-sort sizes #'> :key #'car))))
-         (side (if (> (window-body-width largest t) (* 2 (window-body-height largest t)))
-                   'right
-                 'below))
-         (new-window (split-window largest nil side)))
-    (set-window-buffer new-window (current-buffer))))
+(defun pip-frame--add-additional-buffer (buffer temporary)
+  (let ((windows (window-list (pip-frame--get-frame))))
+    (unless (and temporary
+                 (cl-find buffer windows :key #'window-buffer :test #'eq))
+      (let* ((sizes (mapcar (lambda (w)
+                              (let ((width (window-body-width w t))
+                                    (height (window-body-height w t)))
+                                (cons (+ (* width width) (* height height))
+                                      w)))
+                            windows))
+             (largest (cdr (cl-first (cl-sort sizes #'> :key #'car))))
+             (side (if (> (window-body-width largest t)
+                          (* 2 (window-body-height largest t)))
+                       'right
+                     'below))
+             (new-window (split-window largest nil side)))
+        (set-window-buffer new-window buffer)))))
 
+(defvar pip-frame--buffer-timers '())
+
+(defun pip-frame--make-buffer-temporary (buffer seconds)
+  (when (eq seconds t)
+    (setq seconds pip-frame-temporary-buffer-seconds))
+  (let ((timer (run-with-timer seconds nil #'pip-frame-remove-buffer buffer)))
+    (setq pip-frame--buffer-timers (cons (cons buffer timer)
+                                         pip-frame--buffer-timers))))
+
+(defun pip-frame--delete-buffer-timer (buffer)
+  (let ((timer (alist-get buffer pip-frame--buffer-timers)))
+    (when timer
+      (cancel-timer timer)
+      (setq pip-frame--buffer-timers
+            (assq-delete-all buffer pip-frame--buffer-timers)))))
+  
 ;;;###autoload
-(defun pip-frame-add-buffer ()
-  ""
+(defun pip-frame-add-buffer (&optional buffer-or-name temporary)
+  "Add a buffer to the PIP frame.
+If there is no PIP frame then create one.
+If BUFFER-OR-NAME is specified, add the given buffer to the frame,
+otherwise add the current buffer.
+If TEMPORARY is given, display the buffer in the PIP frame for that
+many seconds and then remove it from the frame.  If t, display it for
+`pip-frame-temporary-buffer-seconds'.
+A buffer can be added and displayed multiple times in the frame.  If
+TEMPORARY is non-nil, the buffer is not displayed again if it is
+already present."
   (interactive)
-  (let ((frame (or (pip-frame--get-frame t))))
+  (let ((frame (pip-frame--get-frame t))
+        (buffer (get-buffer (or buffer-or-name (current-buffer)))))
     (if frame
-        (pip-frame--add-additional-buffer)
-      (pip-frame--make-frame))))
+        (progn
+          (when temporary
+            (pip-frame--delete-buffer-timer buffer))
+          (pip-frame--add-additional-buffer buffer temporary))
+      (pip-frame--make-frame buffer))
+    (when temporary
+      (pip-frame--make-buffer-temporary buffer temporary))))
 
-(defun pip-frame-remove-buffer (buffer-name)
-  ""
+(defun pip-frame-remove-buffer (buffer-or-name)
+  "Remove buffer named BUFFER-OR-NAME from the PIP frame.
+If it is the last buffer in the PIP frame, delete the frame.
+If the buffer is not present in the PIP frame, do nothing."
   (interactive (list (completing-read "Remove PIP buffer: "
                                       (mapcar #'buffer-name (pip-frame--buffers))
                                       nil t)))
-  (let* ((windows (window-list (pip-frame--get-frame)))
-         (windows-to-delete (cl-remove buffer-name windows
-                                       :key #'(lambda (w) (buffer-name (window-buffer w)))
-                                       :test-not #'string=)))
-    (if (= (length windows-to-delete) (length windows))
-        (pip-frame-delete-frame)
-      (mapc #'delete-window windows-to-delete))))
+  (if-let ((frame (pip-frame--get-frame t))
+           (windows (window-list frame))
+           (buffer (get-buffer buffer-or-name))
+           (windows-to-delete (cl-remove buffer windows
+                                         :key #'window-buffer
+                                         :test-not #'eq)))
+      (if (= (length windows-to-delete) (length windows))
+          (pip-frame-delete-frame)
+        (seq-do #'delete-window windows-to-delete))))
 
 (defun pip-frame--move (x y)
   (let ((frame (pip-frame--get-frame)))
@@ -140,18 +197,22 @@ custom option but it can be overriden here."
       (round (* pip-frame-move-step (nth (if vertical 3 2) workarea))))))
 
 (defun pip-frame-move-left ()
+  "Move the PIP frame left."
   (interactive)
   (pip-frame--move (- (pip-frame--move-step nil)) 0))
 
 (defun pip-frame-move-right ()
+  "Move the PIP frame right."
   (interactive)
   (pip-frame--move (pip-frame--move-step nil) 0))
 
 (defun pip-frame-move-up ()
+  "Move the PIP frame up."
   (interactive)
   (pip-frame--move 0 (- (pip-frame--move-step t))))
 
 (defun pip-frame-move-down ()
+  "Move the PIP frame down."
   (interactive)
   (pip-frame--move 0 (pip-frame--move-step t)))
 
@@ -164,9 +225,17 @@ custom option but it can be overriden here."
     map))
   
 (defun pip-frame-move ()
-  ""
+  "Move PIP frame interactively.
+Use arrow keys to move the frame around.
+Any other key stops this command and executes its own command."
   (interactive)
   (message "Use arrow keys to move the frame, any other key to quit")
   (set-transient-map pip-frame-move-map t))
 
 (provide 'pip-frame)
+
+;; Local Variables:
+;; checkdoc-force-docstrings-flag: nil
+;; End:
+
+;;; pip-frame.el ends here