From: Jani Nikula <jani@nikula.org>
To: notmuch@notmuchmail.org
Subject: [RFC PATCH 1/4] emacs: simplify point placement in notmuch-hello
Date: Tue, 17 Apr 2012 08:35:22 +0000
Message-Id:
 <bcfdc0d1969997e89e5abe0b320d77ee2109796a.1334651669.git.jani@nikula.org>
Precedence: list

notmuch-hello (called also through notmuch-hello-update, bound to '='
by default) tries to find the widget under or following point before
refresh, and put the point back to the widget afterwards. The code has
gotten a bit complicated, and has at least the following issues:

1) All the individual section functions have to include code to
   support point placement. If there is no such support, point is
   dropped to the search box. Only saved searches and all tags
   sections support point placement.

2) Point placement is based on widget-value. If there are two widgets
   with the same widget-value (for example a saved search with the
   same name as a tag) the point is moved to the earlier one.

3) When first entering notmuch-hello notmuch-hello-target is nil, and
   point is dropped to the search box.

This patch simplifies the code by removing all point placement based
on widgets. Point is simply saved before refresh, and put back to
where it was. Sometimes, but not very often, this would have the
appearance of moving the point relative to the nearest widgets. IMHO
this is a minor problem compared to the issues listed above.

A downside is that there's no visual cue (point movement) to indicate
that refresh has finished. Then again, neither was there before, if
point was at the beginning of a widget.
---
 emacs/notmuch-hello.el |   70 +++++++++++------------------------------------
 1 files changed, 17 insertions(+), 53 deletions(-)

diff --git a/emacs/notmuch-hello.el b/emacs/notmuch-hello.el
index 71d37b8..9cd907a 100644
--- a/emacs/notmuch-hello.el
+++ b/emacs/notmuch-hello.el
@@ -154,11 +154,6 @@ International Bureau of Weights and Measures."
 (defvar notmuch-hello-url "http://notmuchmail.org"
   "The `notmuch' web site.")
 
-(defvar notmuch-hello-search-pos nil
-  "Position of search widget, if any.
-
-This should only be set by `notmuch-hello-insert-search'.")
-
 (defvar notmuch-hello-custom-section-options
   '((:filter (string :tag "Filter for each tag"))
     (:filter-count (string :tag "Different filter to generate message counts"))
@@ -209,11 +204,8 @@ function produces a section simply by adding content to the current
 buffer.  A section should not end with an empty line, because a
 newline will be inserted after each section by `notmuch-hello'.
 
-Each function should take no arguments.  If the produced section
-includes `notmuch-hello-target' (i.e. cursor should be positioned
-inside this section), the function should return this element's
-position.
-Otherwise, it should return nil.
+Each function should take no arguments. The return value is
+ignored.
 
 For convenience an element can also be a list of the form (FUNC ARG1
 ARG2 .. ARGN) in which case FUNC will be applied to the rest of the
@@ -240,15 +232,6 @@ supported for \"Customized queries section\" items."
 	    notmuch-hello-query-section
 	    (function :tag "Custom section"))))
 
-(defvar notmuch-hello-target nil
-  "Button text at position of point before rebuilding the notmuch-buffer.
-
-This variable contains the text of the button, if any, the
-point was positioned at before the notmuch-hello buffer was
-rebuilt. This should never actually be global and is defined as a
-defvar only for documentation purposes and to avoid a compiler
-warning about it occurring as a free variable.")
-
 (defvar notmuch-hello-hidden-sections nil
   "List of sections titles whose contents are hidden")
 
@@ -449,8 +432,6 @@ Such a list can be computed with `notmuch-hello-query-counts'."
 		     (msg-count (third elem)))
 		(widget-insert (format "%8s "
 				       (notmuch-hello-nice-number msg-count)))
-		(if (string= name notmuch-hello-target)
-		    (setq found-target-pos (point-marker)))
 		(widget-create 'push-button
 			       :notify #'notmuch-hello-widget-search
 			       :notmuch-search-terms query
@@ -589,7 +570,6 @@ Complete list of currently available key bindings:
 (defun notmuch-hello-insert-search ()
   "Insert a search widget."
   (widget-insert "Search: ")
-  (setq notmuch-hello-search-pos (point-marker))
   (widget-create 'editable-field
 		 ;; Leave some space at the start and end of the
 		 ;; search boxes.
@@ -763,13 +743,7 @@ following:
       (set-buffer "*notmuch-hello*")
     (switch-to-buffer "*notmuch-hello*"))
 
-  (let ((notmuch-hello-target (if (widget-at)
-				  (widget-value (widget-at))
-				(condition-case nil
-				    (progn
-				      (widget-forward 1)
-				      (widget-value (widget-at)))
-				  (error nil))))
+  (let ((final-target-pos (point))
 	(inhibit-read-only t))
 
     ;; Delete all editable widget fields.  Editable widget fields are
@@ -788,30 +762,20 @@ following:
       (mapc 'delete-overlay (car all))
       (mapc 'delete-overlay (cdr all)))
 
-    (let (final-target-pos)
-      (mapc
-       (lambda (section)
-	 (let ((point-before (point))
-	       (result (if (functionp section)
-			   (funcall section)
-			 (apply (car section) (cdr section)))))
-	   (if (and (not final-target-pos) (integer-or-marker-p result))
-	       (setq final-target-pos result))
-	   ;; don't insert a newline when the previous section didn't show
-	   ;; anything.
-	   (unless (eq (point) point-before)
-	     (widget-insert "\n"))))
-       notmuch-hello-sections)
-      (widget-setup)
-
-      (when final-target-pos
-	(goto-char final-target-pos)
-	(unless (widget-at)
-	  (widget-forward 1)))
-
-      (unless (widget-at)
-	(when notmuch-hello-search-pos
-	  (goto-char notmuch-hello-search-pos)))))
+    (mapc
+     (lambda (section)
+       (let ((point-before (point)))
+	 (if (functionp section)
+	     (funcall section)
+	   (apply (car section) (cdr section)))
+	 ;; don't insert a newline when the previous section didn't
+	 ;; show anything.
+	 (unless (eq (point) point-before)
+	   (widget-insert "\n"))))
+     notmuch-hello-sections)
+    (widget-setup)
+
+    (goto-char final-target-pos))
   (run-hooks 'notmuch-hello-refresh-hook)
   (setq notmuch-hello-first-run nil))
 
-- 
1.7.1