From c23e7dd3353d55ddfedceb1eb75d6c6a4fb28d04 Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Thu, 20 Sep 2001 18:13:01 +0000
Subject: [PATCH] To each message shown in a summary buffer, attach a mark
 pointing at the line on which the message is shown.  Use this in the code
 that maps from messages to marks, changing it from (slow) linear time in the
 number of messages to constant time.

---
 v7/src/imail/imail-summary.scm | 60 ++++++++++++++++++++--------------
 1 file changed, 36 insertions(+), 24 deletions(-)

diff --git a/v7/src/imail/imail-summary.scm b/v7/src/imail/imail-summary.scm
index 272e1fb19..e956937f1 100644
--- a/v7/src/imail/imail-summary.scm
+++ b/v7/src/imail/imail-summary.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;; $Id: imail-summary.scm,v 1.45 2001/09/20 17:45:26 cph Exp $
+;;; $Id: imail-summary.scm,v 1.46 2001/09/20 18:13:01 cph Exp $
 ;;;
 ;;; Copyright (c) 2000-2001 Massachusetts Institute of Technology
 ;;;
@@ -308,6 +308,12 @@ SUBJECT is a string of regexps separated by commas."
 	(mark-temporary! mark)))))
 
 (define (write-imail-summary-line! message index-digits mark)
+  (let ((m (get-property message 'IMAIL-SUMMARY-MARK #f)))
+    (if m
+	(mark-temporary! m)))
+  (store-property! message
+		   'IMAIL-SUMMARY-MARK
+		   (mark-right-inserting-copy mark))
   (insert-char #\space mark)
   (insert-string (message-flag-markers message) mark)
   (insert-char #\space mark)
@@ -530,29 +536,35 @@ SUBJECT is a string of regexps separated by commas."
 	(round->exact (* (window-y-size window) height)))))
 
 (define (imail-summary-find-message buffer message)
-  (let ((index (message-index message)))
-    (if index
-	(let ((m (imail-summary-first-line buffer)))
-	  (let ((index* (imail-summary-selected-message-index m)))
-	     (cond ((not index*)
-		    (values #f #f))
-		   ((< index* index)
-		    (let loop ((last m))
-		      (let ((m (line-start last 1 #f)))
-			(if m
-			    (let ((index*
-				   (imail-summary-selected-message-index m)))
-			       (cond ((or (not index*)
-					  (> index* index))
-				      (values last #t))
-				     ((= index index*)
-				      (values m #f))
-				     (else
-				      (loop m))))
-			    (values last #t)))))
-		   (else
-		    (values m (> index* index))))))
-	(values #f #f))))
+  (let ((mark (get-property message 'IMAIL-SUMMARY-MARK #f)))
+    (if (and mark
+	     (eqv? (imail-summary-selected-message-index mark)
+		   (message-index message)))
+	(values mark #f)
+	(let ((index (message-index message)))
+	  (if index
+	      (let ((m (imail-summary-first-line buffer)))
+		(let ((index* (imail-summary-selected-message-index m)))
+		   (cond ((not index*)
+			  (values #f #f))
+			 ((< index* index)
+			  (let loop ((last m))
+			    (let ((m (line-start last 1 #f)))
+			      (if m
+				  (let ((index*
+					 (imail-summary-selected-message-index
+					  m)))
+				     (cond ((or (not index*)
+						(> index* index))
+					    (values last #t))
+					   ((= index index*)
+					    (values m #f))
+					   (else
+					    (loop m))))
+				  (values last #t)))))
+			 (else
+			  (values m (> index* index))))))
+	      (values #f #f))))))
 
 (define (imail-summary-first-line buffer)
   (line-start (buffer-start buffer) 2 'LIMIT))
-- 
2.25.1