* lisp/gnus: Further reduce assumptions about gnus-data format

* lisp/gnus/gnus-registry.el (gnus-registry-fetch-message-id-fast)
(gnus-registry-fetch-simplified-message-subject-fast)
(gnus-registry-fetch-sender-fast, gnus-registry-fetch-recipients-fast)
(gnus-registry--set/remove-mark): Don't hardcode assoc for gnus-data-find-in.

* lisp/gnus/gnus-sum.el (gnus-data-update-list): Don't hardcode `nth 2`
for gnus-data-pos.
(gnus-summary-insert-old-articles, gnus-summary-insert-new-articles)
(gnus-summary-first-article-p): Don't hardcode `car` for `gnus-data-number`.
(gnus-summary-move-article, gnus-summary-expire-articles)
(gnus-summary-delete-article): Don't hardcode assoc for gnus-data-find-in.

* lisp/gnus/spam.el (spam-fetch-article-header): Don't hardcode `nth 3`
for gnus-data-header.

3 files changed, 26 insertions, 36 deletions

diff --git a/lisp/gnus/gnus-registry.el b/lisp/gnus/gnus-registry.el
index 634cf926cea..6e549cf246d 100644
--- a/lisp/gnus/gnus-registry.el
+++ b/lisp/gnus/gnus-registry.el
@@ -799,11 +799,9 @@ Overrides existing keywords with FORCE set non-nil."
 
 ;; message field fetchers
 (defun gnus-registry-fetch-message-id-fast (article)
-  "Fetch the Message-ID quickly, using the internal gnus-data-list function."
-  (if (and (numberp article)
-           (assoc article (gnus-data-list nil)))
-      (mail-header-id (gnus-data-header (assoc article (gnus-data-list nil))))
-    nil))
+  "Fetch the Message-ID quickly, using the internal `gnus-data-find' function."
+  (when-let* ((data (and (numberp article) (gnus-data-find article))))
+    (mail-header-id (gnus-data-header data))))
 
 (defun gnus-registry-extract-addresses (text)
   "Extract all the addresses in a normalized way from TEXT.
@@ -830,23 +828,18 @@ Addresses without a name will say \"noname\"."
     nil))
 
 (defun gnus-registry-fetch-simplified-message-subject-fast (article)
-  "Fetch the Subject quickly, using the internal gnus-data-list function."
-  (if (and (numberp article)
-           (assoc article (gnus-data-list nil)))
-      (gnus-string-remove-all-properties
-       (gnus-registry-simplify-subject
-        (mail-header-subject (gnus-data-header
-                              (assoc article (gnus-data-list nil))))))
-    nil))
+  "Fetch the Subject quickly, using the internal `gnus-data-find' function."
+  (when-let* ((data (and (numberp article) (gnus-data-find article))))
+    (gnus-string-remove-all-properties
+     (gnus-registry-simplify-subject
+      (mail-header-subject (gnus-data-header data))))))
 
 (defun gnus-registry-fetch-sender-fast (article)
-  (when-let* ((data (and (numberp article)
-                         (assoc article (gnus-data-list nil)))))
+  (when-let* ((data (and (numberp article) (gnus-data-find article))))
     (mail-header-from (gnus-data-header data))))
 
 (defun gnus-registry-fetch-recipients-fast (article)
-  (when-let* ((data (and (numberp article)
-                         (assoc article (gnus-data-list nil))))
+  (when-let* ((data (and (numberp article) (gnus-data-find article)))
               (extra (mail-header-extra (gnus-data-header data))))
     (gnus-registry-sort-addresses
      (or (cdr (assq 'Cc extra)) "")
@@ -887,9 +880,7 @@ FUNCTION should take two parameters, a mark symbol and the cell value."
     (gnus-message 9 "Applying mark %s to %d articles"
                   mark (length articles))
     (dolist (article articles)
-      (gnus-summary-update-article
-       article
-       (assoc article (gnus-data-list nil))))))
+      (gnus-summary-update-article article (gnus-data-find article)))))
 
 ;; This is ugly code, but I don't know how to do it better.
 (defun gnus-registry-install-shortcuts ()
diff --git a/lisp/gnus/gnus-sum.el b/lisp/gnus/gnus-sum.el
index 4c4445275a6..8fdb766584b 100644
--- a/lisp/gnus/gnus-sum.el
+++ b/lisp/gnus/gnus-sum.el
@@ -3246,7 +3246,7 @@ The following commands are available:
   "Add OFFSET to the POS of all data entries in DATA."
   (setq gnus-newsgroup-data-reverse nil)
   (while data
-    (setcar (nthcdr 2 (car data)) (+ offset (nth 2 (car data))))
+    (cl-incf (gnus-data-pos (car data)) offset)
     (setq data (cdr data))))
 
 (defun gnus-summary-article-pseudo-p (article)
@@ -3574,7 +3574,7 @@ buffer that was in action when the last article was fetched."
   "Return whether ARTICLE is the first article in the buffer."
   (if (not (setq article (or article (gnus-summary-article-number))))
       nil
-    (eq article (caar gnus-newsgroup-data))))
+    (eq article (gnus-data-number (car gnus-newsgroup-data)))))
 
 (defun gnus-summary-last-article-p (&optional article)
   "Return whether ARTICLE is the last article in the buffer."
@@ -4725,10 +4725,10 @@ If LINE, insert the rebuilt thread starting on line LINE."
             (push thr roots))
           (setq thread (cdr thread)))
         ;; We now have all (unique) roots.
-        (if (= (length roots) 1)
-            ;; All the loose roots are now one solid root.
-            (setq thread (car roots))
-          (setq thread (cons subject (gnus-sort-threads roots))))))
+        (setq thread (if (= (length roots) 1)
+                         ;; All the loose roots are now one solid root.
+                         (car roots)
+                       (cons subject (gnus-sort-threads roots))))))
     (let (threads)
       ;; We then insert this thread into the summary buffer.
       (when line
@@ -4738,6 +4738,7 @@ If LINE, insert the rebuilt thread starting on line LINE."
         (if gnus-show-threads
             (gnus-summary-prepare-threads (gnus-cut-threads (list thread)))
           (gnus-summary-prepare-unthreaded thread))
+        ;; FIXME: Why is this `nreverse' safe?  Don't we need `reverse' instead?
         (setq data (nreverse gnus-newsgroup-data))
         (setq threads gnus-newsgroup-threads))
       ;; We splice the new data into the data structure.
@@ -10170,7 +10171,7 @@ ACTION can be either `move' (the default), `crosspost' or `copy'."
           (run-hook-with-args 'gnus-summary-article-delete-hook
                               action
                               (gnus-data-header
-                               (assoc article (gnus-data-list nil)))
+                               (gnus-data-find-in article (gnus-data-list nil)))
                               gnus-newsgroup-name nil
                               select-method)))
        (t
@@ -10280,8 +10281,7 @@ ACTION can be either `move' (the default), `crosspost' or `copy'."
           ;; run the move/copy/crosspost/respool hook
           (run-hook-with-args 'gnus-summary-article-move-hook
                               action
-                              (gnus-data-header
-                               (assoc article (gnus-data-list nil)))
+                              (gnus-data-header (gnus-data-find article))
                               gnus-newsgroup-name
                               to-newsgroup
                               select-method))
@@ -10524,7 +10524,7 @@ This will be the case if the article has both been mailed and posted."
                     (run-hook-with-args
                      'gnus-summary-article-expire-hook
                      'delete
-                     (gnus-data-header (assoc article (gnus-data-list nil)))
+                     (gnus-data-header (gnus-data-find article))
                      gnus-newsgroup-name
                      (cond
                       ((stringp nnmail-expiry-target) nnmail-expiry-target)
@@ -10588,8 +10588,7 @@ confirmation before the articles are deleted."
           (unless (memq (car articles) not-deleted)
             (gnus-summary-mark-article (car articles) gnus-canceled-mark)
             (let* ((article (car articles))
-                   (ghead  (gnus-data-header
-                            (assoc article (gnus-data-list nil)))))
+                   (ghead  (gnus-data-header (gnus-data-find article))))
               (run-hook-with-args 'gnus-summary-article-delete-hook
                                   'delete ghead gnus-newsgroup-name nil
                                   nil)))
@@ -13038,7 +13037,7 @@ If ALL is non-nil, already read articles become readable.
 If ALL is a number, fetch this number of articles."
   (interactive "P")
   (prog1
-      (let ((old (sort (mapcar #'car gnus-newsgroup-data) #'<))
+      (let ((old (sort (mapcar #'gnus-data-number gnus-newsgroup-data) #'<))
             older len)
         (setq older
               ;; Some nntp servers lie about their active range.  When
@@ -13108,7 +13107,7 @@ If ALL is a number, fetch this number of articles."
 (defun gnus-summary-insert-new-articles ()
   "Insert all new articles in this group."
   (interactive)
-  (let ((old (sort (mapcar #'car gnus-newsgroup-data) #'<))
+  (let ((old (sort (mapcar #'gnus-data-number gnus-newsgroup-data) #'<))
         (old-high gnus-newsgroup-highest)
         (nnmail-fetched-sources (list t))
         (new-active (gnus-activate-group gnus-newsgroup-name 'scan))
diff --git a/lisp/gnus/spam.el b/lisp/gnus/spam.el
index 4d31d0a1f1c..d752bf0efee 100644
--- a/lisp/gnus/spam.el
+++ b/lisp/gnus/spam.el
@@ -1520,7 +1520,7 @@ In the case of mover backends, checks the setting of
 ;;       nil)))
 
 (defun spam-fetch-field-fast (article field &optional prepared-data-header)
-  "Fetch a FIELD for ARTICLE with the internal `gnus-data-list' function.
+  "Fetch a FIELD for ARTICLE with the internal `gnus-data-find' function.
 When PREPARED-DATA-HEADER is given, don't look in the Gnus data.
 When FIELD is 'number, ARTICLE can be any number (since we want
 to find it out)."
@@ -1586,7 +1586,7 @@ to find it out)."
 (defun spam-fetch-article-header (article)
   (with-current-buffer gnus-summary-buffer
     (gnus-read-header article)
-    (nth 3 (assq article gnus-newsgroup-data))))
+    (gnus-data-header (gnus-data-find article))))
 ;;}}}
 
 ;;{{{ Spam determination.