master be437883c6d: Amend the handling of c-laomib-cache.

[Alan Mackenzie]

branch: master
commit be437883c6d85f3ff2eddd4359bbfb9230c92910
Author: Alan Mackenzie <acm@muc.de>
Commit: Alan Mackenzie <acm@muc.de>

    Amend the handling of c-laomib-cache.
    
    There was unstable syntactic analysis of lines which were brace
    lists.  This fixes bug#64133.
    
    * lisp/progmodes/cc-engine.el (c-laomib-cache): Allow several
    entries with the same LIM element corresponding to distinct
    scanning regions.
    (c-laomib-get-cache): Add new parameter START.  Adjust to be
    able to have entries with the same LIM element and handle them
    correctly.
    (c-laomib-put-cache): Amend the handling of cache entries with
    the same LIM element.
    (c-looking-at-or-maybe-in-bracelist): Supply the needed new
    argument to c-laomib-get-cache.  Add in a new call to
    c-laomib-put-cache.
---
 lisp/progmodes/cc-engine.el | 44 ++++++++++++++++++++++++++++++++------------
 1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index c4ae8aadd65..721daf9d53f 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -12997,11 +12997,19 @@ comment at the start of cc-engine.el for more info."
 (defvar c-laomib-cache nil)
 (make-variable-buffer-local 'c-laomib-cache)
 
-(defun c-laomib-get-cache (containing-sexp)
-  ;; Get an element from `c-laomib-cache' matching CONTAINING-SEXP.
+(defun c-laomib-get-cache (containing-sexp start)
+  ;; Get an element from `c-laomib-cache' matching CONTAINING-SEXP, and which
+  ;; is suitable for start postiion START.
   ;; Return that element or nil if one wasn't found.
-  (let ((elt (assq containing-sexp c-laomib-cache)))
-    (when elt
+  (let ((ptr c-laomib-cache)
+       elt)
+    (while
+       (and ptr
+            (setq elt (car ptr))
+            (or (not (eq (car elt) containing-sexp))
+                (< start (car (cddr elt)))))
+      (setq ptr (cdr ptr)))
+    (when ptr
       ;; Move the fetched `elt' to the front of the cache.
       (setq c-laomib-cache (delq elt c-laomib-cache))
       (push elt c-laomib-cache)
@@ -13013,18 +13021,26 @@ comment at the start of cc-engine.el for more info."
   ;; the components of the new element (see comment for `c-laomib-cache').
   ;; The return value is of no significance.
   (when lim
-    (let ((old-elt (assq lim c-laomib-cache))
-         ;; (elt (cons containing-sexp (cons start nil)))
+    (let (old-elt
          (new-elt (list lim start end result))
          big-ptr
          (cur-ptr c-laomib-cache)
-         togo (size 0) cur-size
-         )
-      (if old-elt (setq c-laomib-cache (delq old-elt c-laomib-cache)))
+         togo (size 0) cur-size)
+
+      ;; If there is an elt which overlaps with the new element, remove it.
+      (while
+         (and cur-ptr
+              (setq old-elt (car cur-ptr))
+              (or (not (eq (car old-elt) lim))
+                  (not (and (> start (car (cddr old-elt)))
+                            (<= start (cadr old-elt))))))
+       (setq cur-ptr (cdr cur-ptr)))
+      (when (and cur-ptr old-elt)
+       (setq c-laomib-cache (delq old-elt c-laomib-cache)))
 
       (while (>= (length c-laomib-cache) 4)
        ;; We delete the least recently used elt which doesn't enclose START,
-       ;; or..
+       ;; or ...
        (dolist (elt c-laomib-cache)
          (if (or (<= start (cadr elt))
                  (> start (car (cddr elt))))
@@ -13032,8 +13048,10 @@ comment at the start of cc-engine.el for more info."
 
        ;; ... delete the least recently used elt which isn't the biggest.
        (when (not togo)
+         (setq cur-ptr c-laomib-cache)
          (while (cdr cur-ptr)
-           (setq cur-size (- (nth 2 (cadr cur-ptr)) (car (cadr cur-ptr))))
+           (setq cur-size (- (cadr (cadr cur-ptr))
+                             (car (cddr (cadr cur-ptr)))))
            (when (> cur-size size)
              (setq size cur-size
                    big-ptr cur-ptr))
@@ -13225,7 +13243,7 @@ comment at the start of cc-engine.el for more info."
        (goto-char pos)
        (when (eq braceassignp 'dontknow)
          (let* ((cache-entry (and containing-sexp
-                                  (c-laomib-get-cache containing-sexp)))
+                                  (c-laomib-get-cache containing-sexp pos)))
                 (lim2 (or (cadr cache-entry) lim))
                 sub-bassign-p)
            (if cache-entry
@@ -13247,6 +13265,8 @@ comment at the start of cc-engine.el for more info."
                                            )
                        (setq braceassignp (nth 3 cache-entry))
                        (goto-char (nth 2 cache-entry)))
+                   (c-laomib-put-cache containing-sexp
+                                       start (point) sub-bassign-p)
                    (setq braceassignp sub-bassign-p)))
                 (t))