[Patch v2 1/3] emacs: Move colour line from search to lib

[Mark Walters <markwalters1009@gmail.com>]

This patch moves the overlay/colouring from notmuch.el to
notmuch-lib.el. This is in preparation for its use by notmuch-show in
the next patch. This is just a rebased version of the emacs/notmuch.el
and emacs/notmuch-lib.el parts of David Edmondson's patch (see
id:"1325006003-27152-1-git-send-email-dme@dme.org")
---
 emacs/notmuch-lib.el |   18 ++++++++++++++++++
 emacs/notmuch.el     |   15 +--------------
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
index 6907a5f..c8a9351 100644
--- a/emacs/notmuch-lib.el
+++ b/emacs/notmuch-lib.el
@@ -148,6 +148,24 @@ the user hasn't set this variable with the old or new value."
   "Return a query that matches the message with id ID."
   (concat "id:\"" (replace-regexp-in-string "\"" "\"\"" id t t) "\""))
 
+(defun notmuch-color-line (start end line-tag-list spec)
+  "Colorize a line based on tags."
+  ;; Create the overlay only if the message has tags which match one
+  ;; of those specified in `spec'.
+  (let (overlay)
+    (mapc (lambda (elem)
+	    (let ((tag (car elem))
+		  (attributes (cdr elem)))
+	      (when (member tag line-tag-list)
+		(when (not overlay)
+		  (setq overlay (make-overlay start end))
+		  (overlay-put overlay 'priority 5))
+		;; Merge the specified properties with any already
+		;; applied from an earlier match.
+		(overlay-put overlay 'face
+			     (append (overlay-get overlay 'face) attributes)))))
+	  spec)))
+
 ;;
 
 (defun notmuch-common-do-stash (text)
diff --git a/emacs/notmuch.el b/emacs/notmuch.el
index c6236db..d5f40e2 100644
--- a/emacs/notmuch.el
+++ b/emacs/notmuch.el
@@ -612,20 +612,7 @@ foreground and blue background."
 
 (defun notmuch-search-color-line (start end line-tag-list)
   "Colorize lines in `notmuch-show' based on tags."
-  ;; Create the overlay only if the message has tags which match one
-  ;; of those specified in `notmuch-search-line-faces'.
-  (let (overlay)
-    (mapc (lambda (elem)
-	    (let ((tag (car elem))
-		  (attributes (cdr elem)))
-	      (when (member tag line-tag-list)
-		(when (not overlay)
-		  (setq overlay (make-overlay start end)))
-		;; Merge the specified properties with any already
-		;; applied from an earlier match.
-		(overlay-put overlay 'face
-			     (append (overlay-get overlay 'face) attributes)))))
-	  notmuch-search-line-faces)))
+  (notmuch-color-line start end line-tag-list notmuch-search-line-faces))
 
 (defun notmuch-search-author-propertize (authors)
   "Split `authors' into matching and non-matching authors and
-- 
1.7.9.1