sequencer: refactor how original todo list lines are accessed

Previously, we did a lot of arithmetic gymnastics to get at the line in
the todo list (as stored in todo_list.buf). This might have been fast,
but only in terms of execution speed, not in terms of developer time.

Let's refactor this to make it a lot easier to read, and hence to
reason about the correctness of the code. It is not performance-critical
code anyway.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/sequencer.c b/sequencer.c
index c131e39fa93e385cceac96354755a5d788611ddd..eac1c341c1cac4508f4eb4506b6a3de1a014618c 100644 (file)
--- a/sequencer.c
+++ b/sequencer.c
@@ -1871,6 +1871,23 @@ static int count_commands(struct todo_list *todo_list)
        return count;
 }
 
        return count;
 }
 

+static int get_item_line_offset(struct todo_list *todo_list, int index)
+{
+       return index < todo_list->nr ?
+               todo_list->items[index].offset_in_buf : todo_list->buf.len;
+}
+
+static const char *get_item_line(struct todo_list *todo_list, int index)
+{
+       return todo_list->buf.buf + get_item_line_offset(todo_list, index);
+}
+
+static int get_item_line_length(struct todo_list *todo_list, int index)
+{
+       return get_item_line_offset(todo_list, index + 1)
+               -  get_item_line_offset(todo_list, index);
+}
+

 static ssize_t strbuf_read_file_or_whine(struct strbuf *sb, const char *path)
 {
        int fd;
 static ssize_t strbuf_read_file_or_whine(struct strbuf *sb, const char *path)
 {
        int fd;


@@ -2250,29 +2267,27 @@ static int save_todo(struct todo_list *todo_list, struct replay_opts *opts)
        fd = hold_lock_file_for_update(&todo_lock, todo_path, 0);
        if (fd < 0)
                return error_errno(_("could not lock '%s'"), todo_path);
        fd = hold_lock_file_for_update(&todo_lock, todo_path, 0);
        if (fd < 0)
                return error_errno(_("could not lock '%s'"), todo_path);

-       offset = next < todo_list->nr ?
-               todo_list->items[next].offset_in_buf : todo_list->buf.len;
+       offset = get_item_line_offset(todo_list, next);

        if (write_in_full(fd, todo_list->buf.buf + offset,
                        todo_list->buf.len - offset) < 0)
                return error_errno(_("could not write to '%s'"), todo_path);
        if (commit_lock_file(&todo_lock) < 0)
                return error(_("failed to finalize '%s'"), todo_path);
 
        if (write_in_full(fd, todo_list->buf.buf + offset,
                        todo_list->buf.len - offset) < 0)
                return error_errno(_("could not write to '%s'"), todo_path);
        if (commit_lock_file(&todo_lock) < 0)
                return error(_("failed to finalize '%s'"), todo_path);
 

-       if (is_rebase_i(opts)) {
-               const char *done_path = rebase_path_done();
-               int fd = open(done_path, O_CREAT | O_WRONLY | O_APPEND, 0666);
-               int prev_offset = !next ? 0 :
-                       todo_list->items[next - 1].offset_in_buf;
+       if (is_rebase_i(opts) && next > 0) {
+               const char *done = rebase_path_done();
+               int fd = open(done, O_CREAT | O_WRONLY | O_APPEND, 0666);
+               int ret = 0;

 
 

-               if (fd >= 0 && offset > prev_offset &&
-                   write_in_full(fd, todo_list->buf.buf + prev_offset,
-                                 offset - prev_offset) < 0) {
-                       close(fd);
-                       return error_errno(_("could not write to '%s'"),
-                                          done_path);
-               }
-               if (fd >= 0)
-                       close(fd);
+               if (fd < 0)
+                       return 0;
+               if (write_in_full(fd, get_item_line(todo_list, next - 1),
+                                 get_item_line_length(todo_list, next - 1))
+                   < 0)
+                       ret = error_errno(_("could not write to '%s'"), done);
+               if (close(fd) < 0)
+                       ret = error_errno(_("failed to finalize '%s'"), done);
+               return ret;

        }
        return 0;
 }
        }
        return 0;
 }


@@ -3307,8 +3322,7 @@ int skip_unnecessary_picks(void)
                oid = &item->commit->object.oid;
        }
        if (i > 0) {
                oid = &item->commit->object.oid;
        }
        if (i > 0) {

-               int offset = i < todo_list.nr ?
-                       todo_list.items[i].offset_in_buf : todo_list.buf.len;
+               int offset = get_item_line_offset(&todo_list, i);

                const char *done_path = rebase_path_done();
 
                fd = open(done_path, O_CREAT | O_WRONLY | O_APPEND, 0666);
                const char *done_path = rebase_path_done();
 
                fd = open(done_path, O_CREAT | O_WRONLY | O_APPEND, 0666);


@@ -3488,12 +3502,10 @@ int rearrange_squash(void)
                                continue;
 
                        while (cur >= 0) {
                                continue;
 
                        while (cur >= 0) {

-                               int offset = todo_list.items[cur].offset_in_buf;
-                               int end_offset = cur + 1 < todo_list.nr ?
-                                       todo_list.items[cur + 1].offset_in_buf :
-                                       todo_list.buf.len;
-                               char *bol = todo_list.buf.buf + offset;
-                               char *eol = todo_list.buf.buf + end_offset;
+                               const char *bol =
+                                       get_item_line(&todo_list, cur);
+                               const char *eol =
+                                       get_item_line(&todo_list, cur + 1);

 
                                /* replace 'pick', by 'fixup' or 'squash' */
                                command = todo_list.items[cur].command;
 
                                /* replace 'pick', by 'fixup' or 'squash' */
                                command = todo_list.items[cur].command;