Re: [PATCH v3 06/16] sequencer: refactor sequencer_add_exec_commands() to work on a todo_list

> Hi,
> 
> On Fri, 30 Nov 2018, Phillip Wood wrote:
> 
>>> diff --git a/sequencer.c b/sequencer.c
>>> index 900899ef20..11692d0b98 100644
>>> --- a/sequencer.c
>>> +++ b/sequencer.c
>>> @@ -4394,24 +4394,29 @@ int sequencer_make_script(FILE *out, int argc, const
>>> char **argv,
>>>   	return 0;
>>>   }
>>>   
>>> -/*
>>> - * Add commands after pick and (series of) squash/fixup commands
>>> - * in the todo list.
>>> - */
>>> -int sequencer_add_exec_commands(const char *commands)
>>> +static void todo_list_add_exec_commands(struct todo_list *todo_list,
>>> +					struct string_list *commands)
>>> {
>>> -	const char *todo_file = rebase_path_todo();
>>> -	struct todo_list todo_list = TODO_LIST_INIT;
>>> -	struct strbuf *buf = &todo_list.buf;
>>> -	size_t offset = 0, commands_len = strlen(commands);
>>> -	int i, insert;
>>> +	struct strbuf *buf = &todo_list->buf;
>>> +	const char *old_buf = buf->buf;
>>> +	size_t base_length = buf->len;
>>> +	int i, insert, nr = 0, alloc = 0;
>>> +	struct todo_item *items = NULL, *base_items = NULL;
>>>
>>> -	if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
>>> -		return error(_("could not read '%s'."), todo_file);
>>> +	for (i = 0; i < commands->nr; ++i) {
>>> +		strbuf_addstr(buf, commands->items[i].string);
>>> +		strbuf_addch(buf, '\n');
>>> +	}
>>
>> This could cause buf->buf to be reallocated in which case all the
>> todo_list_item.arg pointers will be invalidated.
> 
> I guess it is a good time for me to admit that the `arg` idea was not my
> best. Maybe it would be good to convert that from a pointer to an offset,
> e.g. `size_t arg_offset_in_buf;`? Or maybe we should just drop the
> `_in_buf` suffix and clarify in a comment next to the declaration of the
> fields that they are offsets in the strbuf?