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From: Alban Gruin <alban.gruin@gmail.com>
To: phillip.wood@dunelm.org.uk, git@vger.kernel.org
Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de>,
	Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2 06/16] sequencer: refactor sequencer_add_exec_commands() to work on a todo_list
Date: Fri, 2 Nov 2018 00:31:49 +0100
Message-ID: <c57384de-0996-2294-db8f-0204f9c16226@gmail.com> (raw)
In-Reply-To: <12e849d3-351b-7673-1f14-742d0fbb1ac1@talktalk.net>

Le 30/10/2018 à 17:47, Phillip Wood a écrit :
> On 27/10/2018 22:29, Alban Gruin wrote:
>> This refactors sequencer_add_exec_commands() to work on a todo_list to
>> avoid redundant reads and writes to the disk.
>>
>> An obvious way to do this would be to insert the `exec' command between
>> the other commands, and reparse it once this is done.  This is not what
>> is done here.  Instead, the command is appended to the buffer once, and
>> a new list of items is created.  Items from the old list are copied to
>> it, and new `exec' items are appended when necessary.  This eliminates
>> the need to reparse the todo list, but this also means its buffer cannot
>> be directly written to the disk, hence todo_list_write_to_disk().
> 
> I'd reword this slightly, maybe
> 
> Instead of just inserting the `exec' command between the other commands,
> and re-parsing the buffer at the end the exec command is appended to the
> buffer once, and a new list of items is created.  Items from the old
> list are copied across and new `exec' items are appended when necessary.
>  This eliminates the need to reparse the buffer, but this also means we
> have to use todo_list_write_to_disk() to write the file.
> 
>> sequencer_add_exec_commands() still reads the todo list from the disk,
>> as it is needed by rebase -p.  todo_list_add_exec_commands() works on a
>> todo_list structure, and reparses it at the end.
> 
> I think the saying 'reparses' is confusing as that is what we're trying
> to avoid.
> 
>> complete_action() still uses sequencer_add_exec_commands() for now.
>> This will be changed in a future commit.
>>
>> Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
>> ---
>>   sequencer.c | 69 +++++++++++++++++++++++++++++++++++++----------------
>>   1 file changed, 49 insertions(+), 20 deletions(-)
>>
>> diff --git a/sequencer.c b/sequencer.c
>> index e12860c047..12a3efeca8 100644
>> --- a/sequencer.c
>> +++ b/sequencer.c
>> @@ -4216,6 +4216,50 @@ int sequencer_make_script(FILE *out, int argc,
>> const char **argv,
>>       return 0;
>>   }
>>   +static void todo_list_add_exec_commands(struct todo_list *todo_list,
>> +                    const char *commands)
>> +{
>> +    struct strbuf *buf = &todo_list->buf;
>> +    const char *old_buf = buf->buf;
>> +    size_t commands_len = strlen(commands + strlen("exec ")) - 1;
>> +    int i, first = 1, nr = 0, alloc = 0;
> 
> Minor nit pick, I think it is clearer if first is initialized just
> before the loop as it is in the deleted code below.
> 
>> +    struct todo_item *items = NULL,
>> +        base_item = {TODO_EXEC, NULL, 0, 0, commands_len, 0};
>> +
>> +    strbuf_addstr(buf, commands);
>> +    base_item.offset_in_buf = buf->len - commands_len - 1;
>> +    base_item.arg = buf->buf + base_item.offset_in_buf;
> 
> I think if the user gives --exec more than once on the command line then
> commands will contain more than one exec command so this needs to parse
> commands and create one todo_item for each command.
> 

Ouch, you’re right.  Thanks for the heads up.

>> +
>> +    /*
>> +     * Insert <commands> after every pick. Here, fixup/squash chains
>> +     * are considered part of the pick, so we insert the commands
>> *after*
>> +     * those chains if there are any.
>> +     */
>> +    for (i = 0; i < todo_list->nr; i++) {
>> +        enum todo_command command = todo_list->items[i].command;
>> +        if (todo_list->items[i].arg)
>> +            todo_list->items[i].arg = todo_list->items[i].arg -
>> old_buf + buf->buf;
>> +
>> +        if (command == TODO_PICK && !first) {
>> +            ALLOC_GROW(items, nr + 1, alloc);
>> +            memcpy(items + nr++, &base_item, sizeof(struct todo_item));
> 
> I think it would be clearer to say
>     items[nr++] = base_item;
> rather than using memcpy. This applies below and to some of the other
> patches as well. Also this needs to loop over all the base_items if the
> user gave --exec more than once on the command line.
> 

I agree with you, it’s way more readable, IMO.  But for some reason, I
thought it was not possible to assign a struct to another in C.

> Best Wishes
> 
> Phillip
> 

Cheers,
Alban


  reply index

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-07 19:54 [PATCH 00/15] sequencer: refactor functions working " Alban Gruin
2018-10-07 19:54 ` [PATCH 01/15] sequencer: clear the number of items of a todo_list before parsing Alban Gruin
2018-10-07 19:54 ` [PATCH 02/15] sequencer: make the todo_list structure public Alban Gruin
2018-10-07 19:54 ` [PATCH 03/15] sequencer: refactor check_todo_list() to work on a todo_list Alban Gruin
2018-10-11 11:23   ` Phillip Wood
2018-10-07 19:54 ` [PATCH 04/15] sequencer: refactor sequencer_add_exec_commands() " Alban Gruin
2018-10-11 11:25   ` Phillip Wood
2018-10-11 16:57     ` Alban Gruin
2018-10-12  9:54       ` Phillip Wood
2018-10-12 12:23         ` Alban Gruin
2018-10-07 19:54 ` [PATCH 05/15] sequencer: refactor rearrange_squash() " Alban Gruin
2018-10-07 19:54 ` [PATCH 06/15] sequencer: refactor transform_todos() " Alban Gruin
2018-10-07 19:54 ` [PATCH 07/15] sequencer: make sequencer_make_script() write its script to a strbuf Alban Gruin
2018-10-12 10:01   ` SZEDER Gábor
2018-10-19  8:16     ` Junio C Hamano
2018-10-19  9:27       ` SZEDER Gábor
2018-10-07 19:54 ` [PATCH 08/15] sequencer: change complete_action() to use the refactored functions Alban Gruin
2018-10-11 13:51   ` Phillip Wood
2018-10-11 17:06     ` Alban Gruin
2018-10-07 19:54 ` [PATCH 09/15] sequencer: refactor skip_unnecessary_picks() to work on a todo_list Alban Gruin
2018-10-07 19:54 ` [PATCH 10/15] rebase-interactive: use todo_list_transform() in edit_todo_list() Alban Gruin
2018-10-11 15:16   ` Phillip Wood
2018-10-11 19:58     ` Alban Gruin
2018-10-07 19:54 ` [PATCH 11/15] rebase-interactive: append_todo_help() changes Alban Gruin
2018-10-07 19:54 ` [PATCH 12/15] rebase-interactive: rewrite edit_todo_list() to handle the initial edit Alban Gruin
2018-10-07 19:54 ` [PATCH 13/15] sequencer: use edit_todo_list() in complete_action() Alban Gruin
2018-10-07 19:54 ` [PATCH 14/15] sequencer: fix a call to error() in transform_todo_file() Alban Gruin
2018-10-07 19:54 ` [PATCH 15/15] rebase--interactive: move transform_todo_file() to rebase--interactive.c Alban Gruin
2018-10-07 20:51 ` [PATCH 00/15] sequencer: refactor functions working on a todo_list Alban Gruin
2018-10-27 21:29 ` [PATCH v2 00/16] " Alban Gruin
2018-10-27 21:29   ` [PATCH v2 01/16] sequencer: changes in parse_insn_buffer() Alban Gruin
2018-10-27 21:29   ` [PATCH v2 02/16] sequencer: make the todo_list structure public Alban Gruin
2018-10-27 21:29   ` [PATCH v2 03/16] sequencer: refactor transform_todos() to work on a todo_list Alban Gruin
2018-10-27 21:29   ` [PATCH v2 04/16] sequencer: introduce todo_list_write_to_file() Alban Gruin
2018-10-30 16:28     ` Phillip Wood
2018-11-01 23:31       ` Alban Gruin
2018-10-27 21:29   ` [PATCH v2 05/16] sequencer: refactor check_todo_list() to work on a todo_list Alban Gruin
2018-10-27 21:29   ` [PATCH v2 06/16] sequencer: refactor sequencer_add_exec_commands() " Alban Gruin
2018-10-30 16:47     ` Phillip Wood
2018-11-01 23:31       ` Alban Gruin [this message]
2018-11-02 10:09         ` Phillip Wood
2018-11-02 16:26           ` Alban Gruin
2018-11-02 17:09             ` Phillip Wood
2018-10-27 21:29   ` [PATCH v2 07/16] sequencer: refactor rearrange_squash() " Alban Gruin
2018-10-27 21:29   ` [PATCH v2 08/16] sequencer: make sequencer_make_script() write its script to a strbuf Alban Gruin
2018-10-27 21:29   ` [PATCH v2 09/16] sequencer: change complete_action() to use the refactored functions Alban Gruin
2018-10-27 21:29   ` [PATCH v2 10/16] sequencer: refactor skip_unnecessary_picks() to work on a todo_list Alban Gruin
2018-10-27 21:29   ` [PATCH v2 11/16] rebase-interactive: use todo_list_write_to_file() in edit_todo_list() Alban Gruin
2018-10-27 21:29   ` [PATCH v2 12/16] rebase-interactive: append_todo_help() changes Alban Gruin
2018-10-27 21:29   ` [PATCH v2 13/16] rebase-interactive: rewrite edit_todo_list() to handle the initial edit Alban Gruin
2018-10-27 21:29   ` [PATCH v2 14/16] sequencer: use edit_todo_list() in complete_action() Alban Gruin
2018-10-27 21:29   ` [PATCH v2 15/16] sequencer: fix a call to error() in transform_todo_file() Alban Gruin
2018-10-27 21:29   ` [PATCH v2 16/16] rebase--interactive: move transform_todo_file() to rebase--interactive.c Alban Gruin
2018-10-29  3:05   ` [PATCH v2 00/16] sequencer: refactor functions working on a todo_list Junio C Hamano
2018-10-29 15:34     ` Alban Gruin
2018-11-09  8:07   ` [PATCH v3 " Alban Gruin
2018-11-09  8:07     ` [PATCH v3 01/16] sequencer: changes in parse_insn_buffer() Alban Gruin
2018-11-09  8:07     ` [PATCH v3 02/16] sequencer: make the todo_list structure public Alban Gruin
2018-11-09  8:07     ` [PATCH v3 03/16] sequencer: refactor transform_todos() to work on a todo_list Alban Gruin
2018-11-09  8:07     ` [PATCH v3 04/16] sequencer: introduce todo_list_write_to_file() Alban Gruin
2018-11-09  8:07     ` [PATCH v3 05/16] sequencer: refactor check_todo_list() to work on a todo_list Alban Gruin
2018-11-09  8:07     ` [PATCH v3 06/16] sequencer: refactor sequencer_add_exec_commands() " Alban Gruin
2018-11-09  8:07     ` [PATCH v3 07/16] sequencer: refactor rearrange_squash() " Alban Gruin
2018-11-09  8:07     ` [PATCH v3 08/16] sequencer: make sequencer_make_script() write its script to a strbuf Alban Gruin
2018-11-09  8:07     ` [PATCH v3 09/16] sequencer: change complete_action() to use the refactored functions Alban Gruin
2018-11-09  8:07     ` [PATCH v3 10/16] sequencer: refactor skip_unnecessary_picks() to work on a todo_list Alban Gruin
2018-11-09  8:08     ` [PATCH v3 11/16] rebase-interactive: use todo_list_write_to_file() in edit_todo_list() Alban Gruin
2018-11-09  8:08     ` [PATCH v3 12/16] rebase-interactive: append_todo_help() changes Alban Gruin
2018-11-09  8:08     ` [PATCH v3 13/16] rebase-interactive: rewrite edit_todo_list() to handle the initial edit Alban Gruin
2018-11-09  8:08     ` [PATCH v3 14/16] sequencer: use edit_todo_list() in complete_action() Alban Gruin
2018-11-09  8:08     ` [PATCH v3 15/16] sequencer: fix a call to error() in transform_todo_file() Alban Gruin
2018-11-09  8:08     ` [PATCH v3 16/16] rebase--interactive: move transform_todo_file() to rebase--interactive.c Alban Gruin

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