Johan Herland <johan@xxxxxxxxxxx> writes:
>> +static void get_note_text(struct strbuf *buf, struct notes_tree *t,
>> + const unsigned char *object)
>> +{
>> + const unsigned char *sha1 = get_note(t, object);
>> + char *text;
>> + unsigned long len;
>> + enum object_type type;
>> +
>> + if (!sha1)
>> + return;
>> + text = read_sha1_file(sha1, &type, &len);
>> + if (text && len && type == OBJ_BLOB)
>> + strbuf_add(buf, text, len);
>> + free(text);
>> +}
>> +
>
> What about adding this function to notes.h as a convenience to other
> users of the notes API?
I actually was hoping to hear that I do not have to do this "check
existing and concatenate", and should let the add_note() function
run its default combine_notes method to do the concatenation.
I found a few things I wasn't quite sure in the notes/notes-merge API, by
the way.
- The combine_notes callback is run when a note is inserted into the
in-core notes tree. I felt that this is way too early if you want to
avoid racing with another process (and the patch tries to wrap
create-notes-commit with lock-ref/write-ref-sha1 pair), but perhaps
this is to deal with a case where the calling program calls add_notes()
on the same object multiple times.
- create_notes_commit() dies under a few conditions, but some callers
that are recording advisory/optional notes might want to get an error
and continue.
I think ideally this patch should handle notes like the following, which
is not quite how I coded it:
- initialize in-core notes tree;
- add bunch of notes, without regard to the existing ones, to in-core
notes tree by calling add_notes();
- lock the notes ref and read the "parent"; we may want to add "wait and
retry for a few times until we get the lock" support at lockfile API
level, but doing it at the application level would be fine.
- call create-notes-commit, which in turn merges the in-core
notes with what collides with those already in "parent" by
calling the combine-notes callback, merges and re-balances
the notes tree, and makes a notes commit object;
- update the notes ref with that notes commit, releasing the lock on
the ref.
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