From d28913a9e6609fef96f5baf6e9f4d5055ede744c Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@swtch.com>
Date: Tue, 14 Jan 2020 16:38:34 -0500
Subject: acme: save/restore multiline tags in Dump/Load

The dump substitutes each \n in a multiline tag with a 0xff byte.
Since it is not valid UTF it cannot occur in an ordinary dump file.
Old acmes will just read it in as an error rune.

Fixes #135.
Fixes #153.
---
 src/cmd/acme/rows.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

(limited to 'src/cmd/acme')

diff --git a/src/cmd/acme/rows.c b/src/cmd/acme/rows.c
index 83c64594..7a64fabf 100644
--- a/src/cmd/acme/rows.c
+++ b/src/cmd/acme/rows.c
@@ -316,7 +316,7 @@ rowclean(Row *row)
 void
 rowdump(Row *row, char *file)
 {
-	int i, j, fd, m, n, dumped;
+	int i, j, fd, m, n, start, dumped;
 	uint q0, q1;
 	Biobuf *b;
 	char *buf, *a, *fontname;
@@ -434,9 +434,17 @@ rowdump(Row *row, char *file)
 			m = min(RBUFSIZE, w->tag.file->b.nc);
 			bufread(&w->tag.file->b, 0, r, m);
 			n = 0;
-			while(n<m && r[n]!='\n')
-				n++;
-			Bprint(b, "%.*S\n", n, r);
+			while(n<m) {
+				start = n;
+				while(n<m && r[n]!='\n')
+					n++;
+				Bprint(b, "%.*S", n-start, r+start);
+				if(n<m) {
+					Bputc(b, 0xff); // \n in tag becomes 0xff byte (invalid UTF)
+					n++;
+				}
+			}
+			Bprint(b, "\n");
 			if(dumped){
 				q0 = 0;
 				q1 = t->file->b.nc;
@@ -719,6 +727,10 @@ rowload(Row *row, char *file, int initing)
 		if(l == nil)
 			goto Rescue2;
 		l[Blinelen(b)-1] = 0;
+		/* convert 0xff in multiline tag back to \n */
+		for(i = 0; l[i] != 0; i++)
+			if((uchar)l[i] == 0xff)
+				l[i] = '\n';
 		r = bytetorune(l+5*12, &nr);
 		ns = -1;
 		for(n=0; n<nr; n++){
-- 
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