Restore fontification of delimiters of multiline CC Mode strings.

E.g., on typing the closing delimiter of a string continued onto a second
line, the opening delimiter retained its font-lock-warning-face.

* lisp/progmodes/cc-defs.el (c-c++-raw-string-opener-re)
(c-c++-raw-string-opener-1-re): New constants.
(c-sub-at-c++-raw-string-opener, c-at-c++-raw-string-opener): New macros.

* lisp/progmodes/cc-engine.el (c-raw-string-pos)
(c-depropertize-raw-strings-in-region, c-after-change-unmark-raw-strings):
Replace uses of open-coded raw string regexps by the new constants and macros
in cc-defs.el.

* lisp/progmodes/cc-fonts.el (c-font-lock-raw-strings): Ditto

* lisp/progmodes/cc-mode.el (c-before-change-check-unbalanced-strings): Set
c-new-BEG to the beginning of the string when we encounter its closing ".
When not in a raw string, but in a string, clear syntax-table properties from
its delimiters and set c-new-BEG/END to its limits.
(c-after-change-mark-abnormal-strings): When applying syntax-table properties
to string delimiters, also set c-new-BEG/END to ensure subsequent
fontification.

4 files changed, 56 insertions, 22 deletions

diff --git a/lisp/progmodes/cc-defs.el b/lisp/progmodes/cc-defs.el
index 87ddf3ac1e2..cd4ed6b352e 100644
--- a/lisp/progmodes/cc-defs.el
+++ b/lisp/progmodes/cc-defs.el
@@ -503,6 +503,31 @@ to it is returned.  This function does not modify the point or the mark."
     ;; Emacs <22 + XEmacs
     '(default-value 'sentence-end)))
 
+(defconst c-c++-raw-string-opener-re "R\"\\([^ ()\\\n\r\t]\\{0,16\\}\\)(")
+;; Matches a C++ raw string opener.  Submatch 1 is its identifier.
+
+(defconst c-c++-raw-string-opener-1-re "\"\\([^ ()\\\n\r\t]\\{0,16\\}\\)(")
+;; Matches a C++ raw string opener starting after the initial R.
+
+(defmacro c-sub-at-c++-raw-string-opener ()
+  `(save-excursion
+     (and
+      (if (eq (char-after) ?R)
+          (progn (forward-char) t)
+        (eq (char-before) ?R))
+      (looking-at c-c++-raw-string-opener-1-re))))
+
+(defmacro c-at-c++-raw-string-opener (&optional pos)
+  ;; Return non-nil if POS (default point) is either at the start of a C++ raw
+  ;; string opener, or after the introductory R of one.  The match data is
+  ;; overwritten.  On success the opener's identifier will be (match-string
+  ;; 1).  Text properties on any characters are ignored.
+  (if pos
+      `(save-excursion
+         (goto-char ,pos)
+         (c-sub-at-c++-raw-string-opener))
+    `(c-sub-at-c++-raw-string-opener)))
+
 ;; The following is essentially `save-buffer-state' from lazy-lock.el.
 ;; It ought to be a standard macro.
 (defmacro c-save-buffer-state (varlist &rest body)
diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 6b44aae0884..242954dbf25 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -6607,15 +6607,14 @@ comment at the start of cc-engine.el for more info."
                       (while
                           (and
                            (search-forward-regexp
-                            "R\"\\([^ ()\\\n\r\t]\\{0,16\\}\\)("
+                            c-c++-raw-string-opener-re
                             (1+ here) 'limit)
                            (< (point) here)))
                       (and (eq (point) (1+ here))
                            (match-beginning 1)
                            (goto-char (1- (match-beginning 1)))))))
                   (not (bobp)))))
-           (eq (char-before) ?R)
-           (looking-at "\"\\([^ ()\\\n\r\t]\\{0,16\\}\\)("))
+           (c-at-c++-raw-string-opener))
         (setq open-quote-pos (point)
               open-paren-pos (match-end 1)
               id (match-string-no-properties 1))
@@ -6733,7 +6732,7 @@ comment at the start of cc-engine.el for more info."
                (concat "\\("                                 ; 1
                        c-anchored-cpp-prefix                 ; 2
                        "\\)\\|\\("                           ; 3
-                       "R\"\\([^ ()\\\n\r\t]\\{0,16\\}\\)("  ; 4
+                       c-c++-raw-string-opener-re            ; 4
                        "\\)")
                finish t))
     (when (save-excursion
@@ -6752,7 +6751,7 @@ comment at the start of cc-engine.el for more info."
           (goto-char (match-end 2))     ; after the "#".
           (while (and (< (point) eom)
                       (c-syntactic-re-search-forward
-                       "R\"\\([^ ()\\\n\r\t]\\{0,16\\}\\)(" eom t))
+                       c-c++-raw-string-opener-re eom t))
             (c-depropertize-raw-string
              (match-string-no-properties 1) ; id
              (1+ (match-beginning 0))       ; open quote
@@ -6931,8 +6930,7 @@ comment at the start of cc-engine.el for more info."
       (goto-char end)
       (setq eoll (c-point 'eoll))
       (when (and (null c-old-END-literality)
-                 (search-forward-regexp "R\"\\([^ ()\\\n\r\t]\\{0,16\\}\\)("
-                                 eoll t))
+                 (search-forward-regexp c-c++-raw-string-opener-re eoll t))
         (setq state (c-state-semi-pp-to-literal end))
         (when (eq (cadr state) 'string)
           (unwind-protect
@@ -6969,7 +6967,7 @@ comment at the start of cc-engine.el for more info."
       (while
           (and
            (setq found
-                 (search-forward-regexp "R\"\\([^ ()\\\n\r\t]\\{0,16\\}\\)("
+                 (search-forward-regexp c-c++-raw-string-opener-re
                                        c-new-END 'bound))
            (<= (match-end 0) beg)))
       (when (and found (<= (match-beginning 0) end))
@@ -6983,7 +6981,7 @@ comment at the start of cc-engine.el for more info."
                                              'syntax-table)
                         '(1)))
         (goto-char (1- (cadr c-old-beg-rs)))
-        (unless (looking-at "R\"[^ ()\\\n\r\t]\\{0,16\\}(")
+        (unless (looking-at c-c++-raw-string-opener-re)
           (c-clear-char-property (1+ (point)) 'syntax-table)
           (c-truncate-semi-nonlit-pos-cache (1+ (point)))
           (if (c-search-forward-char-property 'syntax-table '(15)
@@ -6998,7 +6996,7 @@ comment at the start of cc-engine.el for more info."
               (and c-old-beg-rs
                    (eq (car c-old-beg-rs) 'open-delim)))
         (goto-char (cadr c-old-beg-rs))
-        (when (looking-at "\"\\([^ ()\\\n\r\t]\\{0,16\\}\\)(")
+        (when (looking-at c-c++-raw-string-opener-1-re)
           (setq id (match-string-no-properties 1))
           (when (re-search-forward (concat ")" id "\"") nil t) ; No bound.
             (setq c-new-END (point-max))
diff --git a/lisp/progmodes/cc-fonts.el b/lisp/progmodes/cc-fonts.el
index 4a5cf5719be..831fa308866 100644
--- a/lisp/progmodes/cc-fonts.el
+++ b/lisp/progmodes/cc-fonts.el
@@ -1684,11 +1684,8 @@ casts and declarations are fontified.  Used on level 2 and higher."
          (string-start (and (eq (cadr state) 'string)
                             (car (cddr state))))
          (raw-id (and string-start
-                      (save-excursion
-                        (goto-char string-start)
-                        (and (eq (char-before) ?R)
-                             (looking-at "\"\\([^ ()\\\n\r\t]\\{0,16\\}\\)(")
-                             (match-string-no-properties 1)))))
+                      (c-at-c++-raw-string-opener string-start)
+                      (match-string-no-properties 1)))
          (content-start (and raw-id (point))))
     ;; We go round the next loop twice per raw string, once for each "end".
     (while (< (point) limit)
diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index 27ed04fea52..1a360048752 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -1261,7 +1261,8 @@ Note that the style variables are always made local to the buffer."
                    (memq (char-after) c-string-delims)) ; Ignore an unterminated raw string's (.
           ;; Opening " on last line of text (without EOL).
           (c-clear-char-property (point) 'syntax-table)
-          (c-truncate-semi-nonlit-pos-cache (point)))))
+          (c-truncate-semi-nonlit-pos-cache (point))
+          (setq c-new-BEG (min c-new-BEG (point))))))
 
      (t (goto-char end)                 ; point-max
         (when
@@ -1271,17 +1272,24 @@ Note that the style variables are always made local to the buffer."
           (c-clear-char-property (point) 'syntax-table)
           (c-truncate-semi-nonlit-pos-cache (point)))))
 
-    (unless (and c-multiline-string-start-char
-                 (not (c-characterp c-multiline-string-start-char)))
+    (unless 
+        (or (and
+             ;; Don't set c-new-BEG/END if we're in a raw string.
+             (eq beg-literal-type 'string)
+             (c-at-c++-raw-string-opener (car beg-limits)))
+            (and c-multiline-string-start-char
+                 (not (c-characterp c-multiline-string-start-char))))
       (when (and (eq end-literal-type 'string)
                  (not (eq (char-before (cdr end-limits)) ?\()))
         (c-clear-char-property (1- (cdr end-limits)) 'syntax-table)
-        (c-truncate-semi-nonlit-pos-cache (1- (cdr end-limits))))
+        (c-truncate-semi-nonlit-pos-cache (1- (cdr end-limits)))
+        (setq c-new-END (max c-new-END (cdr end-limits))))
 
       (when (and (eq beg-literal-type 'string)
                  (memq (char-after (car beg-limits)) c-string-delims))
         (c-clear-char-property (car beg-limits) 'syntax-table)
-        (c-truncate-semi-nonlit-pos-cache (car beg-limits))))))
+        (c-truncate-semi-nonlit-pos-cache (car beg-limits))
+        (setq c-new-BEG (min c-new-BEG (car beg-limits)))))))
 
 (defun c-after-change-mark-abnormal-strings (beg end _old-len)
   ;; Mark any unbalanced strings in the region (c-new-BEG c-new-END) with
@@ -1352,6 +1360,7 @@ Note that the style variables are always made local to the buffer."
               (car beg-limits))
              (t                         ; comment
               (cdr beg-limits))))
+      ;; Handle one string each time around the next while loop.
       (while
           (and
            (< (point) c-new-END)
@@ -1373,10 +1382,15 @@ Note that the style variables are always made local to the buffer."
           (cond
            ((memq (char-after (match-end 0)) '(?\n ?\r))
             (c-put-char-property (1- (point)) 'syntax-table '(15))
-            (c-put-char-property (match-end 0) 'syntax-table '(15)))
+            (c-put-char-property (match-end 0) 'syntax-table '(15))
+            (setq c-new-BEG (min c-new-BEG (point))
+                  c-new-END (max c-new-END (match-end 0))))
            ((or (eq (match-end 0) (point-max))
                 (eq (char-after (match-end 0)) ?\\)) ; \ at EOB
-            (c-put-char-property (1- (point)) 'syntax-table '(15))))
+            (c-put-char-property (1- (point)) 'syntax-table '(15))
+            (setq c-new-BEG (min c-new-BEG (point))
+                  c-new-END (max c-new-END (match-end 0))) ; Do we need c-new-END?
+            ))
           (goto-char (min (1+ (match-end 0)) (point-max))))
         (setq s nil)))))