checkout_entry(): use the strbuf throughout the function

There is no need to break out the "buf" and "len" members into
separate temporary variables.  Rename path_buf to path and use
path.buf and path.len directly.  This makes it easier to reason about
the data flow in the function.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

entry.c

@@ -237,27 +237,25 @@ static int check_path(const char *path, int len, struct stat *st, int skiplen)
 int checkout_entry(struct cache_entry *ce,
 		   const struct checkout *state, char *topath)
 {
-	static struct strbuf path_buf = STRBUF_INIT;
-	char *path;
+	static struct strbuf path = STRBUF_INIT;
 	struct stat st;
-	int len;
 
 	if (topath)
 		return write_entry(ce, topath, state, 1);
 
-	strbuf_reset(&path_buf);
-	strbuf_add(&path_buf, state->base_dir, state->base_dir_len);
-	strbuf_add(&path_buf, ce->name, ce_namelen(ce));
-	path = path_buf.buf;
-	len = path_buf.len;
+	strbuf_reset(&path);
+	strbuf_add(&path, state->base_dir, state->base_dir_len);
+	strbuf_add(&path, ce->name, ce_namelen(ce));
 
-	if (!check_path(path, len, &st, state->base_dir_len)) {
+	if (!check_path(path.buf, path.len, &st, state->base_dir_len)) {
 		unsigned changed = ce_match_stat(ce, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
 		if (!changed)
 			return 0;
 		if (!state->force) {
 			if (!state->quiet)
-				fprintf(stderr, "%s already exists, no checkout\n", path);
+				fprintf(stderr,
+					"%s already exists, no checkout\n",
+					path.buf);
 			return -1;
 		}
 
@@ -272,12 +270,14 @@ int checkout_entry(struct cache_entry *ce,
 			if (S_ISGITLINK(ce->ce_mode))
 				return 0;
 			if (!state->force)
-				return error("%s is a directory", path);
-			remove_subtree(path);
-		} else if (unlink(path))
-			return error("unable to unlink old '%s' (%s)", path, strerror(errno));
+				return error("%s is a directory", path.buf);
+			remove_subtree(path.buf);
+		} else if (unlink(path.buf))
+			return error("unable to unlink old '%s' (%s)",
+				     path.buf, strerror(errno));
 	} else if (state->not_new)
 		return 0;
-	create_directories(path, len, state);
-	return write_entry(ce, path, state, 0);
+
+	create_directories(path.buf, path.len, state);
+	return write_entry(ce, path.buf, state, 0);
 }