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tspiteritspiteri
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improve position recovery in rust-format-buffer
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‎rust-mode.el

Lines changed: 103 additions & 42 deletions
Original file line numberDiff line numberDiff line change
@@ -1281,6 +1281,88 @@ This is written mainly to be used as `end-of-defun-function' for Rust."
12811281
(kill-buffer))
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(error "Rustfmt failed, see *rustfmt* buffer for details"))))
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1284+
(defconst rust--format-word "\\b\\(else\\|enum\\|fn\\|for\\|if\\|let\\|loop\\|match\\|struct\\|unsafe\\|while\\)\\b")
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(defconst rust--format-line "\\([\n]\\)")
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;; Counts number of matches of regex beginning up to max-beginning,
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;; leaving the point at the beginning of the last match.
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(defun rust--format-count (regex max-beginning)
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(let ((count 0)
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save-point
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beginning)
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(while (and (< (point) max-beginning)
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(re-search-forward regex max-beginning t))
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(setq count (1+ count))
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(setq beginning (match-beginning 1)))
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;; try one more in case max-beginning lies in the middle of a match
1298+
(setq save-point (point))
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(when (re-search-forward regex nil t)
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(let ((try-beginning (match-beginning 1)))
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(if (> try-beginning max-beginning)
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(goto-char save-point)
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(setq count (1+ count))
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(setq beginning try-beginning))))
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(when beginning (goto-char beginning))
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count))
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;; Gets list describing pos or (point).
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;; The list contains:
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;; 1. the number of matches of rust--format-word,
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;; 2. the number of matches of rust--format-line after that,
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;; 3. the number of columns after that.
1313+
(defun rust--format-get-loc (buffer &optional pos)
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(with-current-buffer buffer
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(save-excursion
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(let ((pos (or pos (point)))
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words lines columns)
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(goto-char (point-min))
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(setq words (rust--format-count rust--format-word pos))
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(setq lines (rust--format-count rust--format-line pos))
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(if (> lines 0)
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(if (= (point) pos)
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(setq columns -1)
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(forward-char 1)
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(goto-char pos)
1326+
(setq columns (current-column)))
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(let ((initial-column (current-column)))
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(goto-char pos)
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(setq columns (- (current-column) initial-column))))
1330+
(list words lines columns)))))
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1332+
;; Moves the point forward by count matches of regex up to max-pos,
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;; and returns new max-pos making sure final position does not include another match.
1334+
(defun rust--format-forward (regex count max-pos)
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(when (< (point) max-pos)
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(let ((beginning (point)))
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(while (> count 0)
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(setq count (1- count))
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(re-search-forward regex nil t)
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(setq beginning (match-beginning 1)))
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(when (re-search-forward regex nil t)
1342+
(setq max-pos (min max-pos (match-beginning 1))))
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(goto-char beginning)))
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max-pos)
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1346+
;; Gets the position from a location list obtained using rust--format-get-loc.
1347+
(defun rust--format-get-pos (buffer loc)
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(with-current-buffer buffer
1349+
(save-excursion
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(goto-char (point-min))
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(let ((max-pos (point-max))
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(words (pop loc))
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(lines (pop loc))
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(columns (pop loc)))
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(setq max-pos (rust--format-forward rust--format-word words max-pos))
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(setq max-pos (rust--format-forward rust--format-line lines max-pos))
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(when (> lines 0) (forward-char))
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(let ((initial-column (current-column))
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(save-point (point)))
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(move-end-of-line nil)
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(when (> (current-column) (+ initial-column columns))
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(goto-char save-point)
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(forward-char columns)))
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(min (point) max-pos)))))
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(defun rust-format-buffer ()
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"Format the current buffer using rustfmt."
12861368
(interactive)
@@ -1289,58 +1371,37 @@ This is written mainly to be used as `end-of-defun-function' for Rust."
12891371

12901372
(let* ((current (current-buffer))
12911373
(base (or (buffer-base-buffer current) current))
1292-
buffer-pos
1293-
window-pos)
1374+
buffer-loc
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window-loc)
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(dolist (buffer (buffer-list))
12951377
(when (or (eq buffer base)
12961378
(eq (buffer-base-buffer buffer) base))
1297-
(with-current-buffer buffer
1298-
(push (list buffer
1299-
(line-number-at-pos)
1300-
(current-column))
1301-
buffer-pos))))
1379+
(push (list buffer
1380+
(rust--format-get-loc buffer nil))
1381+
buffer-loc)))
13021382
(dolist (window (window-list))
13031383
(let ((buffer (window-buffer window)))
13041384
(when (or (eq buffer base)
13051385
(eq (buffer-base-buffer buffer) base))
13061386
(let ((start (window-start window))
13071387
(point (window-point window)))
1308-
(with-current-buffer buffer
1309-
(push (list window
1310-
(line-number-at-pos start)
1311-
(save-excursion (goto-char start) (current-column))
1312-
(line-number-at-pos point)
1313-
(save-excursion (goto-char point) (current-column)))
1314-
window-pos))))))
1315-
(rust--format-call current)
1316-
(dolist (pos buffer-pos)
1317-
(let ((buffer (pop pos))
1318-
(line (pop pos))
1319-
(column (pop pos)))
1388+
(push (list window
1389+
(rust--format-get-loc buffer start)
1390+
(rust--format-get-loc buffer point))
1391+
window-loc)))))
1392+
(rust--format-call (current-buffer))
1393+
(dolist (loc buffer-loc)
1394+
(let* ((buffer (pop loc))
1395+
(pos (rust--format-get-pos buffer (pop loc))))
13201396
(with-current-buffer buffer
1321-
;; Move to the same line and column as before. This is best
1322-
;; effort: if rustfmt inserted lines before point, we end up in
1323-
;; the wrong place. See issue #162.
1324-
(goto-char (point-min))
1325-
(forward-line (1- line))
1326-
(forward-char column))))
1327-
(dolist (pos window-pos)
1328-
(let ((window (pop pos))
1329-
(start-line (pop pos))
1330-
(start-column (pop pos))
1331-
(point-line (pop pos))
1332-
(point-column (pop pos)))
1333-
(with-current-buffer (window-buffer window)
1334-
(let ((start (save-excursion (goto-char (point-min))
1335-
(forward-line (1- start-line))
1336-
(forward-char start-column)
1337-
(point)))
1338-
(point (save-excursion (goto-char (point-min))
1339-
(forward-line (1- point-line))
1340-
(forward-char point-column)
1341-
(point))))
1342-
(set-window-start window start)
1343-
(set-window-point window point))))))
1397+
(goto-char pos))))
1398+
(dolist (loc window-loc)
1399+
(let* ((window (pop loc))
1400+
(buffer (window-buffer window))
1401+
(start (rust--format-get-pos buffer (pop loc)))
1402+
(pos (rust--format-get-pos buffer (pop loc))))
1403+
(set-window-start window start)
1404+
(set-window-point window pos))))
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13451406
;; Issue #127: Running this on a buffer acts like a revert, and could cause
13461407
;; the fontification to get out of sync. Call the same hook to ensure it is

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