sequencer: factor out rewrite_file()

Reduce code duplication by extracting a function for rewriting an
existing file.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: rscharfe

sequencer.c

@@ -2665,6 +2665,20 @@ int check_todo_list(void)
 	return res;
 }
 
+static int rewrite_file(const char *path, const char *buf, size_t len)
+{
+	int rc = 0;
+	int fd = open(path, O_WRONLY);
+	if (fd < 0)
+		return error_errno(_("could not open '%s' for writing"), path);
+	if (write_in_full(fd, buf, len) < 0)
+		rc = error_errno(_("could not write to '%s'"), path);
+	if (!rc && ftruncate(fd, len) < 0)
+		rc = error_errno(_("could not truncate '%s'"), path);
+	close(fd);
+	return rc;
+}
+
 /* skip picking commits whose parents are unchanged */
 int skip_unnecessary_picks(void)
 {
@@ -2737,29 +2751,11 @@ int skip_unnecessary_picks(void)
 		}
 		close(fd);
 
-		fd = open(rebase_path_todo(), O_WRONLY, 0666);
-		if (fd < 0) {
-			error_errno(_("could not open '%s' for writing"),
-				    rebase_path_todo());
+		if (rewrite_file(rebase_path_todo(), todo_list.buf.buf + offset,
+				 todo_list.buf.len - offset) < 0) {
 			todo_list_release(&todo_list);
 			return -1;
 		}
-		if (write_in_full(fd, todo_list.buf.buf + offset,
-				todo_list.buf.len - offset) < 0) {
-			error_errno(_("could not write to '%s'"),
-				    rebase_path_todo());
-			close(fd);
-			todo_list_release(&todo_list);
-			return -1;
-		}
-		if (ftruncate(fd, todo_list.buf.len - offset) < 0) {
-			error_errno(_("could not truncate '%s'"),
-				    rebase_path_todo());
-			todo_list_release(&todo_list);
-			close(fd);
-			return -1;
-		}
-		close(fd);
 
 		todo_list.current = i;
 		if (is_fixup(peek_command(&todo_list, 0)))
@@ -2944,15 +2940,7 @@ int rearrange_squash(void)
 			}
 		}
 
-		fd = open(todo_file, O_WRONLY);
-		if (fd < 0)
-			res = error_errno(_("could not open '%s'"), todo_file);
-		else if (write(fd, buf.buf, buf.len) < 0)
-			res = error_errno(_("could not write to '%s'"), todo_file);
-		else if (ftruncate(fd, buf.len) < 0)
-			res = error_errno(_("could not truncate '%s'"),
-					   todo_file);
-		close(fd);
+		res = rewrite_file(todo_file, buf.buf, buf.len);
 		strbuf_release(&buf);
 	}