emacs: hello: use batch count

This modifies notmuch hello to use the new count --batch
functionality. It should give exactly the same results as before but
under many conditions it should be much faster. In particular it is
much faster for remote use.

The code is a little ugly as it has to do some working out of the
query when asking the query and some when dealing with the result.
However, the code path is exactly the same in both local and remote
use.

1 files changed, 32 insertions, 20 deletions

diff --git a/emacs/notmuch-hello.el b/emacs/notmuch-hello.el
index 00b78e1e..cda79f1d 100644
--- a/emacs/notmuch-hello.el
+++ b/emacs/notmuch-hello.el
@@ -381,26 +381,38 @@ The result is the list of elements of the form (NAME QUERY COUNT).
 The values :show-empty-searches, :filter and :filter-count from
 options will be handled as specified for
 `notmuch-hello-insert-searches'."
-  (notmuch-remove-if-not
-   #'identity
-   (mapcar
-    (lambda (elem)
-      (let* ((name (car elem))
-	     (query-and-count (if (consp (cdr elem))
-				  ;; do we have a different query for the message count?
-				  (cons (second elem) (third elem))
-				(cons (cdr elem) (cdr elem))))
-	     (message-count
-	      (string-to-number
-	       (notmuch-saved-search-count
-		(notmuch-hello-filtered-query (cdr query-and-count)
-					      (or (plist-get options :filter-count)
-						 (plist-get options :filter)))))))
-	(and (or (plist-get options :show-empty-searches) (> message-count 0))
-	     (list name (notmuch-hello-filtered-query
-			 (car query-and-count) (plist-get options :filter))
-		   message-count))))
-    query-alist)))
+  (with-temp-buffer
+    (dolist (elem query-alist nil)
+      (let ((count-query (if (consp (cdr elem))
+			     ;; do we have a different query for the message count?
+			     (third elem)
+			   (cdr elem))))
+	(insert
+	 (notmuch-hello-filtered-query count-query
+				       (or (plist-get options :filter-count)
+					   (plist-get options :filter)))
+	 "\n")))
+
+    (call-process-region (point-min) (point-max) notmuch-command
+			 t t nil "count" "--batch")
+    (goto-char (point-min))
+
+    (notmuch-remove-if-not
+     #'identity
+     (mapcar
+      (lambda (elem)
+	(let ((name (car elem))
+	      (search-query (if (consp (cdr elem))
+				 ;; do we have a different query for the message count?
+				 (second elem)
+			      (cdr elem)))
+	      (message-count (prog1 (read (current-buffer))
+				(forward-line 1))))
+	  (and (or (plist-get options :show-empty-searches) (> message-count 0))
+	       (list name (notmuch-hello-filtered-query
+			   search-query (plist-get options :filter))
+		     message-count))))
+      query-alist))))
 
 (defun notmuch-hello-insert-buttons (searches)
   "Insert buttons for SEARCHES.