[PATCH 5/6] shortlog: optimize out useless "<none>" normalization

From: Jeff King <peff@peff.net>
Date: Jan 15, 2016, 17:10 UTC
Message-ID: <20160115171006.GE21102@sigill.intra.peff.net>
In-Reply-To: <20160115170627.GA20983@sigill.intra.peff.net>

If we are in --summary mode, we will always pass <none> to insert_one_record, which will then do some normalization (e.g., cutting out "[PATCH]"). There's no point in doing so if we aren't going to use the result anyway.

This drops my best-of-five for "git shortlog -ns HEAD" on linux.git from:

  real    0m5.257s
  user    0m5.104s
  sys     0m0.156s

to:

  real    0m5.194s
  user    0m5.028s
  sys     0m0.168s

That's only 1%, but arguably the result is clearer to read, as we're able to group our variable declarations inside the conditional block. It also opens up further optimization possibilities for future patches.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/shortlog.c | 63 +++++++++++++++++++++++++++++-------------------------
 1 file changed, 34 insertions(+), 29 deletions(-)

diff --git a/builtin/shortlog.c b/builtin/shortlog.c
index 3e1e0d6..c2bf9b2 100644
--- a/builtin/shortlog.c
+++ b/builtin/shortlog.c
@@ -31,13 +31,9 @@ static void insert_one_record(struct shortlog *log,
 			      const char *author,
 			      const char *oneline)
 {
-	const char *dot3 = log->common_repo_prefix;
-	char *buffer, *p;
 	struct string_list_item *item;
 	const char *mailbuf, *namebuf;
 	size_t namelen, maillen;
-	const char *eol;
-	struct strbuf subject = STRBUF_INIT;
 	struct strbuf namemailbuf = STRBUF_INIT;
 	struct ident_split ident;
 
@@ -59,34 +55,43 @@ static void insert_one_record(struct shortlog *log,
 	if (item->util == NULL)
 		item->util = xcalloc(1, sizeof(struct string_list));
 
-	/* Skip any leading whitespace, including any blank lines. */
-	while (*oneline && isspace(*oneline))
-		oneline++;
-	eol = strchr(oneline, '\n');
-	if (!eol)
-		eol = oneline + strlen(oneline);
-	if (starts_with(oneline, "[PATCH")) {
-		char *eob = strchr(oneline, ']');
-		if (eob && (!eol || eob < eol))
-			oneline = eob + 1;
-	}
-	while (*oneline && isspace(*oneline) && *oneline != '\n')
-		oneline++;
-	format_subject(&subject, oneline, " ");
-	buffer = strbuf_detach(&subject, NULL);
-
-	if (dot3) {
-		int dot3len = strlen(dot3);
-		if (dot3len > 5) {
-			while ((p = strstr(buffer, dot3)) != NULL) {
-				int taillen = strlen(p) - dot3len;
-				memcpy(p, "/.../", 5);
-				memmove(p + 5, p + dot3len, taillen + 1);
+	if (log->summary)
+		string_list_append(item->util, xstrdup(""));
+	else {
+		const char *dot3 = log->common_repo_prefix;
+		char *buffer, *p;
+		struct strbuf subject = STRBUF_INIT;
+		const char *eol;
+
+		/* Skip any leading whitespace, including any blank lines. */
+		while (*oneline && isspace(*oneline))
+			oneline++;
+		eol = strchr(oneline, '\n');
+		if (!eol)
+			eol = oneline + strlen(oneline);
+		if (starts_with(oneline, "[PATCH")) {
+			char *eob = strchr(oneline, ']');
+			if (eob && (!eol || eob < eol))
+				oneline = eob + 1;
+		}
+		while (*oneline && isspace(*oneline) && *oneline != '\n')
+			oneline++;
+		format_subject(&subject, oneline, " ");
+		buffer = strbuf_detach(&subject, NULL);
+
+		if (dot3) {
+			int dot3len = strlen(dot3);
+			if (dot3len > 5) {
+				while ((p = strstr(buffer, dot3)) != NULL) {
+					int taillen = strlen(p) - dot3len;
+					memcpy(p, "/.../", 5);
+					memmove(p + 5, p + dot3len, taillen + 1);
+				}
 			}
 		}
-	}
 
-	string_list_append(item->util, buffer);
+		string_list_append(item->util, buffer);
+	}
 }
 
 /*

-- 
2.7.0.244.g0701a9d