From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 21 Mar 2017 22:03:29 +0000 (-0700)
Subject: Merge branch 'rs/commit-parsing-optim' into maint
X-Git-Tag: v2.12.2~13
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/d6bc22e64b9572f72b2eb26fa1ce9d697d9d0d8e?hp=93abd178716c20024422f902d2f0bc560be44dc7

Merge branch 'rs/commit-parsing-optim' into maint

The code that parses header fields in the commit object has been
updated for (micro)performance and code hygiene.

* rs/commit-parsing-optim:
commit: don't check for space twice when looking for header
commit: be more precise when searching for headers
---

diff --git a/commit.c b/commit.c
index 2cf85158b4..fab8269731 100644
--- a/commit.c
+++ b/commit.c
@@ -1308,11 +1308,11 @@ void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
 
 static inline int standard_header_field(const char *field, size_t len)
 {
-	return ((len == 4 && !memcmp(field, "tree ", 5)) ||
-		(len == 6 && !memcmp(field, "parent ", 7)) ||
-		(len == 6 && !memcmp(field, "author ", 7)) ||
-		(len == 9 && !memcmp(field, "committer ", 10)) ||
-		(len == 8 && !memcmp(field, "encoding ", 9)));
+	return ((len == 4 && !memcmp(field, "tree", 4)) ||
+		(len == 6 && !memcmp(field, "parent", 6)) ||
+		(len == 6 && !memcmp(field, "author", 6)) ||
+		(len == 9 && !memcmp(field, "committer", 9)) ||
+		(len == 8 && !memcmp(field, "encoding", 8)));
 }
 
 static int excluded_header_field(const char *field, size_t len, const char **exclude)
@@ -1322,8 +1322,7 @@ static int excluded_header_field(const char *field, size_t len, const char **exc
 
 	while (*exclude) {
 		size_t xlen = strlen(*exclude);
-		if (len == xlen &&
-		    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
+		if (len == xlen && !memcmp(field, *exclude, xlen))
 			return 1;
 		exclude++;
 	}
@@ -1354,12 +1353,11 @@ static struct commit_extra_header *read_commit_extra_header_lines(
 		strbuf_reset(&buf);
 		it = NULL;
 
-		eof = strchr(line, ' ');
-		if (next <= eof)
+		eof = memchr(line, ' ', next - line);
+		if (!eof)
 			eof = next;
-
-		if (standard_header_field(line, eof - line) ||
-		    excluded_header_field(line, eof - line, exclude))
+		else if (standard_header_field(line, eof - line) ||
+			 excluded_header_field(line, eof - line, exclude))
 			continue;
 
 		it = xcalloc(1, sizeof(*it));