[PATCH v2 4/7] emacs: Use result text properties for search result iteration

[Mark Walters]

On Sat, 14 Jul 2012, Austin Clements <amdragon at MIT.EDU> wrote:
> This simplifies the traversal of regions of results and eliminates the
> need for save-excursions (which tend to get in the way of maintaining
> point when we make changes to the buffer).  It also fixes some strange
> corner cases in the old line-based code where results that bordered
> the region but were not included in it could be affected by region
> commands.  Coincidentally, this also essentially enables multi-line
> search result formats; the only remaining non-multi-line-capable
> functions are notmuch-search-{next,previous}-thread, which are only
> used interactively.

Having understood how macros work (thanks to Austin's patient
explanations on irc) this looks fine. So +1 for the whole series.

Best wishes

Mark
> ---
>  emacs/notmuch.el |   61 ++++++++++++++++++++++++++++++------------------------
>  1 file changed, 34 insertions(+), 27 deletions(-)
>
> diff --git a/emacs/notmuch.el b/emacs/notmuch.el
> index 8e1a769..92ba2c1 100644
> --- a/emacs/notmuch.el
> +++ b/emacs/notmuch.el
> @@ -427,17 +427,33 @@ returns nil"
>      (next-single-property-change (or pos (point)) 'notmuch-search-result
>  				 nil (point-max))))
>  
> +(defmacro notmuch-search-do-results (beg end pos-sym &rest body)
> +  "Invoke BODY for each result between BEG and END.
> +
> +POS-SYM will be bound to the point at the beginning of the
> +current result."
> +  (declare (indent 3))
> +  (let ((end-sym (make-symbol "end"))
> +	(first-sym (make-symbol "first")))
> +    `(let ((,pos-sym (notmuch-search-result-beginning ,beg))
> +	   ;; End must be a marker in case body changes the text
> +	   (,end-sym (copy-marker ,end))
> +	   ;; Make sure we examine one result, even if (= beg end)
> +	   (,first-sym t))
> +       ;; We have to be careful if the region extends beyond the
> +       ;; results.  In this case, pos could be null or there could be
> +       ;; no result at pos.
> +       (while (and ,pos-sym (or (< ,pos-sym ,end-sym) ,first-sym))
> +	 (when (notmuch-search-get-result ,pos-sym)
> +	   , at body)
> +	 (setq ,pos-sym (notmuch-search-result-end ,pos-sym)
> +	       ,first-sym nil)))))
> +
>  (defun notmuch-search-properties-in-region (property beg end)
> -  (save-excursion
> -    (let ((output nil)
> -	  (last-line (line-number-at-pos end))
> -	  (max-line (- (line-number-at-pos (point-max)) 2)))
> -      (goto-char beg)
> -      (beginning-of-line)
> -      (while (<= (line-number-at-pos) (min last-line max-line))
> -	(setq output (cons (get-text-property (point) property) output))
> -	(forward-line 1))
> -      output)))
> +  (let (output)
> +    (notmuch-search-do-results beg end pos
> +      (push (get-text-property pos property) output))
> +    output))
>  
>  (defun notmuch-search-find-thread-id ()
>    "Return the thread for the current thread"
> @@ -517,28 +533,19 @@ and will also appear in a buffer named \"*Notmuch errors*\"."
>    (plist-get (notmuch-search-get-result pos) :tags))
>  
>  (defun notmuch-search-get-tags-region (beg end)
> -  (save-excursion
> -    (let ((output nil)
> -	  (last-line (line-number-at-pos end))
> -	  (max-line (- (line-number-at-pos (point-max)) 2)))
> -      (goto-char beg)
> -      (while (<= (line-number-at-pos) (min last-line max-line))
> -	(setq output (append output (notmuch-search-get-tags)))
> -	(forward-line 1))
> -      output)))
> +  (let (output)
> +    (notmuch-search-do-results beg end pos
> +      (setq output (append output (notmuch-search-get-tags pos))))
> +    output))
>  
>  (defun notmuch-search-tag-region (beg end &optional tag-changes)
>    "Change tags for threads in the given region."
>    (let ((search-string (notmuch-search-find-thread-id-region-search beg end)))
>      (setq tag-changes (funcall 'notmuch-tag search-string tag-changes))
> -    (save-excursion
> -      (let ((last-line (line-number-at-pos end))
> -	    (max-line (- (line-number-at-pos (point-max)) 2)))
> -	(goto-char beg)
> -	(while (<= (line-number-at-pos) (min last-line max-line))
> -	  (notmuch-search-set-tags
> -	   (notmuch-update-tags (notmuch-search-get-tags) tag-changes))
> -	  (forward-line))))))
> +    (notmuch-search-do-results beg end pos
> +      (notmuch-search-set-tags
> +       (notmuch-update-tags (notmuch-search-get-tags pos) tag-changes)
> +       pos))))
>  
>  (defun notmuch-search-tag (&optional tag-changes)
>    "Change tags for the currently selected thread or region.
> -- 
> 1.7.10