Use a modification count cache to verify and commit memoized folder

orders, instead of blocking interrupts, so that MEMOIZE-FOLDER-ORDER
may now be interrupted.

Memoize the folder order immediately before it is assigned to a folder
in SET-FOLDER-ORDER!.  This means that it can no longer be delayed
until actually needed, but also that if it is interrupted it won't
actually set the folder's order and thereby wedge IMAIL until the
messages are sorted.

Allow message indices to fall outside the range of folder orders, and
leave them as they are, in case the folder order has not been updated
yet to reflect them.

diff --git a/v7/src/imail/imail-core.scm b/v7/src/imail/imail-core.scm
index 207a1c8c37e856286c475f5fd2c580e017dcbdf6..80020887f3477c8a6f273786706e4f0b3c55d247 100644 (file)
--- a/v7/src/imail/imail-core.scm
+++ b/v7/src/imail/imail-core.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Id: imail-core.scm,v 1.159 2007/03/11 04:32:07 riastradh Exp $
+$Id: imail-core.scm,v 1.160 2007/03/11 15:04:31 riastradh Exp $
 
 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
     1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
@@ -410,6 +410,7 @@ USA.
 (define set-folder-order!
   (let ((modifier (slot-modifier <folder> 'ORDER)))
     (lambda (folder order)
+      (if order (memoize-folder-order order folder))
       (let ((original-order (folder-order folder)))
         (modifier folder order)
         (cond ((and (not original-order) order)
@@ -732,15 +733,18 @@ USA.
                   (constructor make-folder-order (predicate selector)))
   (predicate #f read-only #t)
   (selector #f read-only #t)
-  (tree #f))
+  (tree #f)
+  (modification-count -1))
 
 (define (map-folder-index folder index)
   (let ((order (folder-order folder)))
     (if order
        (begin
          (memoize-folder-order order folder)
-          (%message-index
-           (wt-tree/index-datum (folder-order-tree order) index)))
+          (let ((tree (folder-order-tree order)))
+            (if (< index (wt-tree/size tree))
+                (%message-index (wt-tree/index-datum tree index))
+                index)))
        index)))
 
 (define (unmap-folder-index folder index)
@@ -748,10 +752,11 @@ USA.
     (if order
        (begin
          (memoize-folder-order order folder)
-          (wt-tree/rank (folder-order-tree order)
-                        (cons ((folder-order-selector order)
-                               (%get-message folder index))
-                              index)))
+          (or (wt-tree/rank (folder-order-tree order)
+                            (cons ((folder-order-selector order)
+                                   (%get-message folder index))
+                                  index))
+              index))
        index)))
 
 (define (make-wt-message-tree key<?)
@@ -763,22 +768,32 @@ USA.
                (< (cdr a) (cdr b))))))))
 \f
 (define (memoize-folder-order order folder)
-  (without-interrupts
+  (let loop ()
+    (let ((modification-count (folder-order-modification-count order)))
+      (if (not (= modification-count (object-modification-count folder)))
+          (if (not (folder-order-tree order))
+              (begin
+                (set-folder-order-tree!
+                 order
+                 (build-folder-order-tree order folder))
+                (set-folder-order-modification-count! order modification-count)
+                (loop)))))))
+
+(define (build-folder-order-tree order folder)
+  ((imail-ui:message-wrapper "Sorting folder")
    (lambda ()
-     (if (not (folder-order-tree order))
-         ((imail-ui:message-wrapper "Sorting folder")
-          (lambda ()
-            (let ((length (folder-length folder))
-                  (selector (folder-order-selector order))
-                  (tree (make-wt-message-tree (folder-order-predicate order))))
-              (do ((index 0 (+ index 1)))
-                  ((= index length))
-                (imail-ui:progress-meter index #f)
-                (let ((message (%get-message folder index)))
-                  (wt-tree/add! tree
-                                (cons (selector message) index)
-                                message)))
-              (set-folder-order-tree! order tree))))))))
+     (let ((length (folder-length folder))
+           (selector (folder-order-selector order))
+           (tree (make-wt-message-tree (folder-order-predicate order))))
+       (do ((index 0 (+ index 1)))
+           ((= index length))
+         (if (zero? (remainder index 100))
+             (imail-ui:progress-meter index #f))
+         (let ((message (%get-message folder index)))
+           (wt-tree/add! tree
+                         (cons (selector message) index)
+                         message)))
+       tree))))
 
 (define (update-folder-order folder modification-type arguments)
   (without-interrupts