From c455e609bdf065c3177eec29234348809cdc372c Mon Sep 17 00:00:00 2001 From: Alan Mackenzie Date: Thu, 14 Nov 2019 19:51:01 +0000 Subject: [PATCH] CC Mode: Fix two bugs in the "state cache". This (along with a suggestion to the OP to set open-paren-in-column-0-is-defun-start to nil) fixes bug #37910. It may also have fixed bug #5490 and bug #18072. * lisp/progmodes/cc-engine.el (c-state-cache-non-literal-place): Remove thi non-sensical function, replacing it with .... (c-state-cache-lower-good-pos): New function. (c-renarrow-state-cache, c-append-lower-brace-pair-to-state-cache) (c-remove-stale-state-cache, c-remove-stale-state-cache-backwards): Instead of altering the state-cache list structure with setcar and setcdr, use setq and consing. (c-parse-state-1): Call c-state-cache-lower-good-pos rather than c-state-cache-non-literal-place. --- lisp/progmodes/cc-engine.el | 61 +++++++++++++++++++++++++------------ 1 file changed, 42 insertions(+), 19 deletions(-) diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el index 15b23bb2e6a..e2f822951c8 100644 --- a/lisp/progmodes/cc-engine.el +++ b/lisp/progmodes/cc-engine.el @@ -3366,19 +3366,35 @@ comment at the start of cc-engine.el for more info." (or (car (c-state-literal-at pos)) pos)) -(defsubst c-state-cache-non-literal-place (pos state) - ;; Return a position outside of a string/comment/macro at or before POS. - ;; STATE is the parse-partial-sexp state at POS. - (let ((res (if (or (nth 3 state) ; in a string? - (and (nth 4 state) - (not (eq (nth 7 state) 'syntax-table)))) ; in a comment? - (nth 8 state) - pos))) +(defun c-state-cache-lower-good-pos (here pos state) + ;; Return a good pos (in the sense of `c-state-cache-good-pos') at the + ;; lowest[*] position between POS and HERE which is syntactically equivalent + ;; to HERE. This position may be HERE itself. POS is before HERE in the + ;; buffer. + ;; [*] We don't actually always determine this exact position, since this + ;; would require a disproportionate amount of work, given that this function + ;; deals only with a corner condition, and POS and HERE are typically on + ;; adjacent lines. We actually return either POS, when POS is a good + ;; position, HERE otherwise. Exceptionally, when POS is in a comment, but + ;; HERE not, we can return the position of the end of the comment. + (let (s) (save-excursion - (goto-char res) - (if (c-beginning-of-macro) - (point) - res)))) + (goto-char pos) + (when (nth 8 state) ; POS in a comment or string. Move out of it. + (setq s (parse-partial-sexp pos here nil nil state 'syntax-table)) + (when (< (point) here) + (setq pos (point) + state s))) + (if (eq (point) here) ; HERE is in the same literal as POS + pos + (setq s (parse-partial-sexp pos here (1+ (car state)) nil state nil)) + (cond + ((> (car s) (car state)) ; Moved into a paren between POS and HERE + here) + ((not (eq (nth 6 s) (car state))) ; Moved out of a paren between POS + ; and HERE + here) + (t pos)))))) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; Stuff to do with point-min, and coping with any literal there. @@ -3685,7 +3701,13 @@ comment at the start of cc-engine.el for more info." ; brace pair. (setq c-state-cache nil c-state-cache-good-pos c-state-min-scan-pos) - (setcdr ptr nil) + ;; Do not alter the original `c-state-cache' structure, since there + ;; may be a loop suspended which is looping through that structure. + ;; This may have been the cause of bug #37910. + (let ((cdr-ptr (cdr ptr))) + (setcdr ptr nil) + (setq c-state-cache (copy-sequence c-state-cache)) + (setcdr ptr cdr-ptr)) (setq c-state-cache-good-pos (1+ (c-state-cache-top-lparen)))) ))) @@ -3788,11 +3810,12 @@ comment at the start of cc-engine.el for more info." (setq new-cons (cons bra (1+ ce))) (cond ((consp (car c-state-cache)) - (setcar c-state-cache new-cons)) + (setq c-state-cache (cons new-cons (cdr c-state-cache)))) ((and (numberp (car c-state-cache)) ; probably never happens (< ce (car c-state-cache))) - (setcdr c-state-cache - (cons new-cons (cdr c-state-cache)))) + (setq c-state-cache + (cons (car c-state-cache) + (cons new-cons (cdr c-state-cache))))) (t (setq c-state-cache (cons new-cons c-state-cache))))) ;; We haven't found a brace pair. Record this in the cache. @@ -3993,7 +4016,7 @@ comment at the start of cc-engine.el for more info." (when (and c-state-cache (consp (car c-state-cache)) (> (cdar c-state-cache) upper-lim)) - (setcar c-state-cache (caar c-state-cache)) + (setq c-state-cache (cons (caar c-state-cache) (cdr c-state-cache))) (setq scan-back-pos (car c-state-cache) cons-separated t)) @@ -4130,7 +4153,7 @@ comment at the start of cc-engine.el for more info." ;; knowledge of what's inside these braces, we have no alternative but ;; to direct the caller to scan the buffer from the opening brace. (setq pos (caar c-state-cache)) - (setcar c-state-cache pos) + (setq c-state-cache (cons pos (cdr c-state-cache))) (list (1+ pos) pos t)) ; return value. We've just converted a brace pair ; entry into a { entry, so the caller needs to ; search for a brace pair before the {. @@ -4380,7 +4403,7 @@ comment at the start of cc-engine.el for more info." (setq c-state-cache-good-pos (if (and bopl-state (< good-pos (- here c-state-cache-too-far))) - (c-state-cache-non-literal-place here-bopl bopl-state) + (c-state-cache-lower-good-pos here here-bopl bopl-state) good-pos))) ((eq strategy 'backward) -- 2.39.5