New experimental feature to save&restore window and frame setup.

* etc/NEWS: Document new Desktop option `desktop-save-windows'.

* lisp/desktop.el (desktop-save-windows): New defcustom.
  (desktop--saved-states): New var.
  (desktop--excluded-frame-parameters): New defconst.
  (desktop--filter-frame-parms, desktop--find-frame-in-display)
  (desktop--restore-windows, desktop--save-windows): New functions.
  (desktop-save): Call `desktop--save-windows'.
  (desktop-read): Call `desktop--restore-windows'.

4 files changed, 98 insertions, 0 deletions

diff --git a/etc/ChangeLog b/etc/ChangeLog
index c8748396f60..93ba05bc377 100644
--- a/etc/ChangeLog
+++ b/etc/ChangeLog
@@ -1,3 +1,7 @@
+2013-06-27  Juanma Barranquero  <lekktu@gmail.com>
+
+        * NEWS: Document new Desktop option `desktop-save-windows'.
+
 2013-06-27  Stephen Berman  <stephen.berman@gmx.net>
 
         * NEWS: Mention new version of todo-mode.el and obsoleting and
diff --git a/etc/NEWS b/etc/NEWS
index 85cf3b80acd..f5ab7c60ce5 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -237,6 +237,9 @@ on the given date.
 *** `desktop-auto-save-timeout' defines the number of seconds between
 auto-saves of the desktop.
 
+*** `desktop-save-windows' enables saving and restoring the window/frame
+configuration.
+
 ** Dired
 
 *** New minor mode `dired-hide-details-mode' hides details.
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 4c0952f88f5..2c36162b017 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,14 @@
+2013-06-27  Juanma Barranquero  <lekktu@gmail.com>
+
+        New experimental feature to save&restore window and frame setup.
+        * desktop.el (desktop-save-windows): New defcustom.
+        (desktop--saved-states): New var.
+        (desktop--excluded-frame-parameters): New defconst.
+        (desktop--filter-frame-parms, desktop--find-frame-in-display)
+        (desktop--restore-windows, desktop--save-windows): New functions.
+        (desktop-save): Call `desktop--save-windows'.
+        (desktop-read): Call `desktop--restore-windows'.
+
 2013-06-27  Lars Magne Ingebrigtsen  <larsi@gnus.org>
 
         * net/shr.el (add-face-text-property): Removed compat definition.
diff --git a/lisp/desktop.el b/lisp/desktop.el
index 8e66a9b81a3..68c2b26b5d7 100644
--- a/lisp/desktop.el
+++ b/lisp/desktop.el
@@ -371,6 +371,12 @@ modes are restored automatically; they should not be listed here."
   :type '(repeat symbol)
   :group 'desktop)
 
+(defcustom desktop-save-windows nil
+  "When non-nil, save window/frame configuration to desktop file."
+  :type 'boolean
+  :group 'desktop
+  :version "24.4")
+
 (defcustom desktop-file-name-format 'absolute
   "Format in which desktop file names should be saved.
 Possible values are:
@@ -556,6 +562,9 @@ DIRNAME omitted or nil means use `desktop-dirname'."
   "Checksum of the last auto-saved contents of the desktop file.
 Used to avoid writing contents unchanged between auto-saves.")
 
+(defvar desktop--saved-states nil
+  "Internal use only.")
+
 ;; ----------------------------------------------------------------------------
 ;; Desktop file conflict detection
 (defvar desktop-file-modtime nil
@@ -858,6 +867,42 @@ DIRNAME must be the directory in which the desktop file will be saved."
 
 
 ;; ----------------------------------------------------------------------------
+(defconst desktop--excluded-frame-parameters
+  '(buffer-list
+    buffer-predicate
+    buried-buffer-list
+    explicit-name
+    font-backend
+    minibuffer
+    name
+    outer-window-id
+    parent-id
+    window-id
+    window-system)
+  "Frame parameters not saved or restored.")
+
+(defun desktop--filter-frame-parms (frame)
+  "Return frame parameters of FRAME.
+Parameters in `desktop--excluded-frame-parameters' are excluded.
+Internal use only."
+  (let (params)
+    (dolist (param (frame-parameters frame))
+      (unless (memq (car param) desktop--excluded-frame-parameters)
+        (push param params)))
+    params))
+
+(defun desktop--save-windows ()
+  "Save window/frame state, as a global variable.
+Intended to be called from `desktop-save'.
+Internal use only."
+  (setq desktop--saved-states
+        (and desktop-save-windows
+             (mapcar (lambda (frame)
+                       (cons (desktop--filter-frame-parms frame)
+                             (window-state-get (frame-root-window frame) t)))
+                     (frame-list))))
+  (desktop-outvar 'desktop--saved-states))
+
 ;;;###autoload
 (defun desktop-save (dirname &optional release auto-save)
   "Save the desktop in a desktop file.
@@ -896,6 +941,9 @@ and don't save the buffer if they are the same."
           (save-excursion (run-hooks 'desktop-save-hook))
           (goto-char (point-max))
           (insert "\n;; Global section:\n")
+          ;; Called here because we save the window/frame state as a global
+          ;; variable for compatibility with previous Emacsen.
+          (desktop--save-windows)
           (mapc (function desktop-outvar) desktop-globals-to-save)
           (when (memq 'kill-ring desktop-globals-to-save)
             (insert
@@ -954,6 +1002,37 @@ This function also sets `desktop-dirname' to nil."
 (defvar desktop-lazy-timer nil)
 
 ;; ----------------------------------------------------------------------------
+(defun desktop--find-frame-in-display (frames display)
+  (let (result)
+    (while (and frames (not result))
+      (if (equal display (frame-parameter (car frames) 'display))
+          (setq result (car frames))
+        (setq frames (cdr frames))))
+    result))
+
+(defun desktop--restore-windows ()
+  "Restore window/frame configuration.
+Internal use only."
+  (when (and desktop-save-windows desktop--saved-states)
+    (condition-case nil
+        (let ((frames (frame-list)))
+          (dolist (state desktop--saved-states)
+            (let* ((fconfig (car state))
+                   (display (cdr (assq 'display fconfig)))
+                   (frame (desktop--find-frame-in-display frames display)))
+              (if (not frame)
+                  ;; no frames in the display -- make a new one
+                  (setq frame (make-frame-on-display display fconfig))
+                ;; found one -- reuse and remove from list
+                (setq frames (delq frame frames))
+                (modify-frame-parameters frame fconfig))
+              ;; restore windows
+              (window-state-put (cdr state) (frame-root-window frame) 'safe)))
+          ;; delete any remaining frames
+          (mapc #'delete-frame frames))
+      (error
+       (message "Error loading window configuration from desktop file")))))
+
 ;;;###autoload
 (defun desktop-read (&optional dirname)
   "Read and process the desktop file in directory DIRNAME.
@@ -1022,6 +1101,7 @@ Using it may cause conflicts.  Use it anyway? " owner)))))
             (switch-to-buffer (car (buffer-list)))
             (run-hooks 'desktop-delay-hook)
             (setq desktop-delay-hook nil)
+            (desktop--restore-windows)
             (run-hooks 'desktop-after-read-hook)
             (message "Desktop: %d buffer%s restored%s%s."
                      desktop-buffer-ok-count