Add has_extension()

The little helper has_extension() documents through its name what we are
trying to do and makes sure we don't forget the underrun check.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-help.c

@@ -140,7 +140,7 @@ static void list_commands(const char *exec_path, const char *pattern)
 			continue;
 
 		entlen = strlen(de->d_name);
-		if (4 < entlen && !strcmp(de->d_name + entlen - 4, ".exe"))
+		if (has_extension(de->d_name, entlen, ".exe"))
 			entlen -= 4;
 
 		if (longest < entlen)

git-compat-util.h

@@ -139,6 +139,12 @@ static inline ssize_t xwrite(int fd, const void *buf, size_t len)
 	}
 }
 
+static inline int has_extension(const char *filename, int len, const char *ext)
+{
+	int extlen = strlen(ext);
+	return len > extlen && !memcmp(filename + len - extlen, ext, extlen);
+}
+
 /* Sane ctype - no locale, and works with signed chars */
 #undef isspace
 #undef isdigit

http-fetch.c

@@ -870,7 +870,7 @@ static void process_ls_pack(struct remote_ls_ctx *ls)
 
 	if (strlen(ls->dentry_name) == 63 &&
 	    !strncmp(ls->dentry_name, "objects/pack/pack-", 18) &&
-	    !strncmp(ls->dentry_name+58, ".pack", 5)) {
+	    has_extension(ls->dentry_name, 63, ".pack")) {
 		get_sha1_hex(ls->dentry_name + 18, sha1);
 		setup_index(ls->repo, sha1);
 	}

index-pack.c

@@ -447,7 +447,7 @@ int main(int argc, char **argv)
 		usage(index_pack_usage);
 	if (!index_name) {
 		int len = strlen(pack_name);
-		if (len < 5 || strcmp(pack_name + len - 5, ".pack"))
+		if (!has_extension(pack_name, len, ".pack"))
 			die("packfile name '%s' does not end with '.pack'",
 			    pack_name);
 		index_name_buf = xmalloc(len);

local-fetch.c

@@ -44,7 +44,7 @@ static int setup_indices(void)
 	while ((de = readdir(dir)) != NULL) {
 		int namelen = strlen(de->d_name);
 		if (namelen != 50 ||
-		    strcmp(de->d_name + namelen - 5, ".pack"))
+		    !has_extension(de->d_name, namelen, ".pack"))
 			continue;
 		get_sha1_hex(de->d_name + 5, sha1);
 		setup_index(sha1);

refs.c

@@ -147,7 +147,7 @@ static int do_for_each_ref(const char *base, int (*fn)(const char *path, const u
 			namelen = strlen(de->d_name);
 			if (namelen > 255)
 				continue;
-			if (namelen>5 && !strcmp(de->d_name+namelen-5,".lock"))
+			if (has_extension(de->d_name, namelen, ".lock"))
 				continue;
 			memcpy(path + baselen, de->d_name, namelen+1);
 			if (stat(git_path("%s", path), &st) < 0)

sha1_file.c

@@ -590,7 +590,7 @@ static void prepare_packed_git_one(char *objdir, int local)
 		int namelen = strlen(de->d_name);
 		struct packed_git *p;
 
-		if (strcmp(de->d_name + namelen - 4, ".idx"))
+		if (!has_extension(de->d_name, namelen, ".idx"))
 			continue;
 
 		/* we have .idx.  Is it a file we can map? */

verify-pack.c

@@ -10,7 +10,7 @@ static int verify_one_pack(char *arg, int verbose)
 		/* Should name foo.idx, but foo.pack may be named;
 		 * convert it to foo.idx
 		 */
-		if (!strcmp(arg + len - 5, ".pack")) {
+		if (has_extension(arg, len, ".pack")) {
 			strcpy(arg + len - 5, ".idx");
 			len--;
 		}