[PATCH 2/6] shortlog: use strbufs to read from stdin

[Jeff King <peff@peff.net>]

We currently use fixed-size buffers with fgets(), which
could lead to incorrect results in the unlikely event that a
line had something like "Author:" at exactly its 1024th
character.

But it's easy to convert this to a strbuf, and because we
can reuse the same buffer through the loop, we don't even
pay the extra allocation cost.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/shortlog.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/builtin/shortlog.c b/builtin/shortlog.c
index ab25b44..6c0a72e 100644
--- a/builtin/shortlog.c
+++ b/builtin/shortlog.c
@@ -91,21 +91,24 @@ static void insert_one_record(struct shortlog *log,
 
 static void read_from_stdin(struct shortlog *log)
 {
-	char author[1024], oneline[1024];
+	struct strbuf author = STRBUF_INIT;
+	struct strbuf oneline = STRBUF_INIT;
 
-	while (fgets(author, sizeof(author), stdin) != NULL) {
+	while (strbuf_getline(&author, stdin, '\n') != EOF) {
 		const char *v;
-		if (!skip_prefix(author, "Author: ", &v) &&
-		    !skip_prefix(author, "author ", &v))
+		if (!skip_prefix(author.buf, "Author: ", &v) &&
+		    !skip_prefix(author.buf, "author ", &v))
 			continue;
-		while (fgets(oneline, sizeof(oneline), stdin) &&
-		       oneline[0] != '\n')
+		while (strbuf_getline(&oneline, stdin, '\n') != EOF &&
+		       oneline.len)
 			; /* discard headers */
-		while (fgets(oneline, sizeof(oneline), stdin) &&
-		       oneline[0] == '\n')
+		while (strbuf_getline(&oneline, stdin, '\n') != EOF &&
+		       !oneline.len)
 			; /* discard blanks */
-		insert_one_record(log, v, oneline);
+		insert_one_record(log, v, oneline.buf);
 	}
+	strbuf_release(&author);
+	strbuf_release(&oneline);
 }
 
 void shortlog_add_commit(struct shortlog *log, struct commit *commit)
-- 
2.7.0.248.g5eafd77