strbuf_addbuf(): allow passing the same buf to dst and src

gitster · gitster · commit 81d2caefedef · 2010-01-13T12:12:52.000-08:00
If sb and sb2 are the same (i.e. doubling the string), the underlying
strbuf_add() can make sb2-&gt;buf invalid by calling strbuf_grow(sb) at
the beginning; if realloc(3) done by strbuf_grow() needs to move the
string, strbuf_add() will read from an already freed buffer.

Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/strbuf.h b/strbuf.h
@@ -105,6 +105,7 @@ static inline void strbuf_addstr(struct strbuf *sb, const char *s) {
 	strbuf_add(sb, s, strlen(s));
 }
 static inline void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2) {
+	strbuf_grow(sb, sb2->len);
 	strbuf_add(sb, sb2->buf, sb2->len);
 }
 extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len);

Original file line number	Diff line number	Diff line change
`@@ -105,6 +105,7 @@ static inline void strbuf_addstr(struct strbuf sb, const char s) {`
`105`	`105`	`strbuf_add(sb, s, strlen(s));`
`106`	`106`	`}`
`107`	`107`	`static inline void strbuf_addbuf(struct strbuf sb, const struct strbuf sb2) {`
	`108`	`+ strbuf_grow(sb, sb2->len);`
`108`	`109`	`strbuf_add(sb, sb2->buf, sb2->len);`
`109`	`110`	`}`
`110`	`111`	`extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len);`