ed

commit de8be38be7f9111fc80f747c519037f5a18e7b29
parent 7b4af7e0476a5ef0427e2f66921dd164052ed06f
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Sun, 13 Dec 2015 20:53:29 +0100

Discard undo data after new edit

Every time we read a file for editing (first use of r,
or any use of e and E) we have to clear the undo data,
because we cannot undo the action.

Diffstat:
M
ed.c
 | 
19
++++++++++++++-----

1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/ed.c b/ed.c
@@ -227,15 +227,20 @@ setglobal(int i, int v)
 }
 
 static void
+clearundo(void)
+{
+	free(udata.vec);
+	udata.vec = NULL;
+	newcmd = udata.nr = udata.cap = 0;
+}
+
+static void
 relink(int to1, int from1, int from2, int to2)
 {
 	struct link *p;
 
-	if (newcmd) {
-		free(udata.vec);
-		udata.vec = NULL;
-		newcmd = udata.nr = udata.cap = 0;
-	}
+	if (newcmd)
+		clearundo();
 	if (udata.nr >= udata.cap) {
 		size_t siz = (udata.cap + 10) * sizeof(struct link);
 		if ((p = realloc(udata.vec, siz)) == NULL)
@@ -312,6 +317,7 @@ setscratch()
 	int k;
 
 	clearbuf();
+	clearundo();
 	strcpy(tmpname, "ed.XXXXXX");
 	if ((scratch = mkstemp(tmpname)) < 0) {
 		/* try /tmp if cwd is not writable */
@@ -322,6 +328,7 @@ setscratch()
 	if ((k = makeline("", NULL)))
 		error("input/output error in scratch file");
 	relink(k, k, k, k);
+	clearundo();
 	modflag = 0;
 }
 
@@ -607,6 +614,7 @@ doread(char *fname)
 
 	if (savfname[0] == '\0') {
 		modflag = 0;
+		clearundo();
 		strcpy(savfname, fname);
 	}
 }
@@ -1188,6 +1196,7 @@ repeat:
 		strcpy(savfname, getfname());
 		deflines(curln, curln);
 		doread(savfname);
+		clearundo();
 		modflag = 0;
 		break;
 	default: