[PATCH 19/27] [GSOC] ref-filter: remove strlen from find_subpos

From: ZheNing Hu via GitGitGadget <gitgitgadget@gmail.com>
Date: Aug 13, 2021, 08:23 UTC
Message-ID: <20cbc3645f14a2090195abeb880cca1541aa1206.1628842990.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.1016.git.1628842990.gitgitgadget@gmail.com>

From: ZheNing Hu <adlternative@gmail.com>

find_subpos() needs to use strlen() to get the length of the object content, but in the caller of find_subpos(): grab_sub_body_contents(), we can already get the length of the object content through data->size. So add a `size_t buf_size` in find_subpos(), and pass data->size to it. This can lead to weak performance optimizations.

Signed-off-by: ZheNing Hu <adlternative@gmail.com>
Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Hariom Verma <hariom18599@gmail.com>
---
 ref-filter.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/ref-filter.c b/ref-filter.c
index 3ccb531e073..be4c4405b12 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -1346,7 +1346,7 @@ static void grab_person(enum atom_type type, struct atom_value *val, int deref,
 	}
 }
 
-static void find_subpos(const char *buf,
+static void find_subpos(const char *buf, size_t buf_size,
 			const char **sub, size_t *sublen,
 			const char **body, size_t *bodylen,
 			size_t *nonsiglen,
@@ -1354,12 +1354,12 @@ static void find_subpos(const char *buf,
 {
 	struct strbuf payload = STRBUF_INIT;
 	struct strbuf signature = STRBUF_INIT;
+	const char *begin = buf;
 	const char *eol;
-	const char *end = buf + strlen(buf);
 	const char *sigstart;
 
 	/* parse signature first; we might not even have a subject line */
-	parse_signature(buf, end - buf, &payload, &signature);
+	parse_signature(buf, buf_size, &payload, &signature);
 
 	/* skip past header until we hit empty line */
 	while (*buf && *buf != '\n') {
@@ -1372,7 +1372,7 @@ static void find_subpos(const char *buf,
 	while (*buf == '\n')
 		buf++;
 	*sig = strbuf_detach(&signature, siglen);
-	sigstart = buf + parse_signed_buffer(buf, strlen(buf));
+	sigstart = buf + parse_signed_buffer(buf, buf_size - (buf - begin));
 
 	/* subject is first non-empty line */
 	*sub = buf;
@@ -1395,7 +1395,7 @@ static void find_subpos(const char *buf,
 	while (*buf == '\n' || *buf == '\r')
 		buf++;
 	*body = buf;
-	*bodylen = strlen(buf);
+	*bodylen = buf_size - (buf - begin);
 	*nonsiglen = sigstart - buf;
 }
 
@@ -1462,7 +1462,7 @@ static void grab_sub_body_contents(struct atom_value *val, int deref, struct exp
 		     !starts_with(name, "contents")))
 			continue;
 		if (!subpos)
-			find_subpos(buf,
+			find_subpos(buf, data->size,
 				    &subpos, &sublen,
 				    &bodypos, &bodylen, &nonsiglen,
 				    &sigpos, &siglen);

-- 
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