Re: [PATCH 6/6] fetch-pack: introduce negotiator API

2018-06-05 Thread Jonathan Tan
On Tue, Jun 5, 2018 at 5:37 PM, Jonathan Nieder  wrote:
>> This patch is written to be more easily reviewed: static functions are
>> moved verbatim from fetch-pack.c to negotiator/default.c, and it can be
>> seen that the lines replaced by negotiator->X() calls are present in the
>> X() functions respectively.
>
> nit: s/more//

OK.

>> +#include "fetch-negotiator.h"
>
> To avoid various standards weirdness, the first #include in all files
> should be git-compat-util.h, cache.h, or builtin.h.  I tend to just
> use git-compat-util.h.

OK.

>> +#include "cache.h"
>
> What does this need from cache.h?

If I remember correctly, I needed something, but I might not. I'll
remove it if so.

>> +#include "commit.h"
>
> optional: could use a forward-declaration "struct commit;" since we
> only use pointers instead of the complete type.  Do we document when
> to prefer forward-declaration and when to #include complete type
> definitions somewhere?

I'll use the forward declaration then.

> [...]
>> +struct fetch_negotiator {
>
> Neat.  Can this file include an overview of the calling sequence / how
> I use this API? E.g.
>
> /*
>  * Standard calling sequence:
>  * 1. Obtain a struct fetch_negotiator * using [...]
>  * 2. For each [etc]
>  * 3. Free resources associated with the negotiator by calling
>  *release(this).  This frees the pointer; it cannot be
>  *reused.
>  */
>
> That would be a good complement to the reference documentation in the
> struct definition.

OK.

>> @@ -1061,19 +944,17 @@ static struct ref *do_fetch_pack(struct 
>> fetch_pack_args *args,
>>   if (!server_supports("deepen-relative") && args->deepen_relative)
>>   die(_("Server does not support --deepen"));
>>
>> - if (marked)
>> - for_each_ref(clear_marks, NULL);
>> - marked = 1;
>> - if (everything_local(, args, , sought, nr_sought)) {
>> + if (everything_local(, args, , sought, nr_sought)) {
>>   packet_flush(fd[1]);
>>   goto all_done;
>>   }
>> - if (find_common(, args, fd, , ref) < 0)
>> + if (find_common(, args, fd, , ref) < 0)
>>   if (!args->keep_pack)
>>   /* When cloning, it is not unusual to have
>>* no common commit.
>>*/
>>   warning(_("no common commits"));
>> + negotiator.release();
>
> Should this go after the all_done so that it doesn't get bypassed in
> the everything_local case?

Good point - will do.

>> @@ -1434,6 +1316,7 @@ static struct ref *do_fetch_pack_v2(struct 
>> fetch_pack_args *args,
>>   continue;
>>   }
>>   }
>> + negotiator.release();
>>
>>   oidset_clear();
>
> nit: could put the negotiator.release() after the blank
> line, in the same paragraph as the other free calls like
> oidset_clear().

OK.

>> +++ b/negotiator/default.c
>> @@ -0,0 +1,173 @@
>> +#include "default.h"
>
> First #include should be "git-compat-util.h".

OK.

> [...]
>> +/*
>> +   This function marks a rev and its ancestors as common.
>> +   In some cases, it is desirable to mark only the ancestors (for example
>> +   when only the server does not yet know that they are common).
>> +*/
>
> Not about this change: comments should have ' *' at the start of each
> line (could do in a preparatory patch or a followup).

I'll add a followup.

>> --- /dev/null
>> +++ b/negotiator/default.h
>> @@ -0,0 +1,8 @@
>> +#ifndef NEGOTIATOR_DEFAULT_H
>> +#define NEGOTIATOR_DEFAULT_H
>> +
>> +#include "fetch-negotiator.h"
>> +
>> +void default_negotiator_init(struct fetch_negotiator *negotiator);
>
> optional: same question about whether to use a forward declaration as in
> fetch-negotiator.h.

I'll use a forward declaration.


Re: [PATCH 6/6] fetch-pack: introduce negotiator API

2018-06-05 Thread Jonathan Nieder
Jonathan Tan wrote:

> Introduce the new files fetch-negotiator.{h,c}, which contains an API
> behind which the details of negotiation are abstracted. Currently, only
> one algorithm is available: the existing one.
>
> This patch is written to be more easily reviewed: static functions are
> moved verbatim from fetch-pack.c to negotiator/default.c, and it can be
> seen that the lines replaced by negotiator->X() calls are present in the
> X() functions respectively.

nit: s/more//

> Signed-off-by: Jonathan Tan 
> ---
>  Makefile |   2 +
>  fetch-negotiator.c   |   7 ++
>  fetch-negotiator.h   |  45 ++
>  fetch-pack.c | 207 ++-
>  negotiator/default.c | 173 
>  negotiator/default.h |   8 ++
>  object.h |   3 +-
>  7 files changed, 282 insertions(+), 163 deletions(-)
>  create mode 100644 fetch-negotiator.c
>  create mode 100644 fetch-negotiator.h
>  create mode 100644 negotiator/default.c
>  create mode 100644 negotiator/default.h

Looks like a job for --color-moved. :)

[...]
> --- /dev/null
> +++ b/fetch-negotiator.c
> @@ -0,0 +1,7 @@
> +#include "fetch-negotiator.h"

To avoid various standards weirdness, the first #include in all files
should be git-compat-util.h, cache.h, or builtin.h.  I tend to just
use git-compat-util.h.

[...]
> +++ b/fetch-negotiator.h
> @@ -0,0 +1,45 @@
> +#ifndef FETCH_NEGOTIATOR
> +#define FETCH_NEGOTIATOR
> +
> +#include "cache.h"

What does this need from cache.h?

> +#include "commit.h"

optional: could use a forward-declaration "struct commit;" since we
only use pointers instead of the complete type.  Do we document when
to prefer forward-declaration and when to #include complete type
definitions somewhere?

[...]
> +struct fetch_negotiator {

Neat.  Can this file include an overview of the calling sequence / how
I use this API? E.g.

/*
 * Standard calling sequence:
 * 1. Obtain a struct fetch_negotiator * using [...]
 * 2. For each [etc]
 * 3. Free resources associated with the negotiator by calling
 *release(this).  This frees the pointer; it cannot be
 *reused.
 */

That would be a good complement to the reference documentation in the
struct definition.

[...]
> +++ b/object.h
> @@ -28,7 +28,8 @@ struct object_array {
>  /*
>   * object flag allocation:
>   * revision.h:   0-1026
> - * fetch-pack.c: 05
> + * fetch-pack.c: 01
> + * negotiator/default.c:   2--5
>   * walker.c: 0-2

Nice!

[...]
> +++ b/fetch-pack.c
[...]
> @@ -462,7 +348,7 @@ static int find_common(struct data *data, struct 
> fetch_pack_args *args,
>   retval = -1;
>   if (args->no_dependents)
>   goto done;
> - while ((oid = get_rev(data))) {
> + while ((oid = negotiator->next(negotiator))) {
[etc]

I like it. :)

[...]
> @@ -988,7 +870,8 @@ static struct ref *do_fetch_pack(struct fetch_pack_args 
> *args,
>   struct object_id oid;
>   const char *agent_feature;
>   int agent_len;
> - struct data data = { { compare_commits_by_commit_date } };
> + struct fetch_negotiator negotiator;
> + fetch_negotiator_init();

Sane.

[...]
> @@ -1061,19 +944,17 @@ static struct ref *do_fetch_pack(struct 
> fetch_pack_args *args,
>   if (!server_supports("deepen-relative") && args->deepen_relative)
>   die(_("Server does not support --deepen"));
>  
> - if (marked)
> - for_each_ref(clear_marks, NULL);
> - marked = 1;
> - if (everything_local(, args, , sought, nr_sought)) {
> + if (everything_local(, args, , sought, nr_sought)) {
>   packet_flush(fd[1]);
>   goto all_done;
>   }
> - if (find_common(, args, fd, , ref) < 0)
> + if (find_common(, args, fd, , ref) < 0)
>   if (!args->keep_pack)
>   /* When cloning, it is not unusual to have
>* no common commit.
>*/
>   warning(_("no common commits"));
> + negotiator.release();

Should this go after the all_done so that it doesn't get bypassed in
the everything_local case?

[...]
> @@ -1434,6 +1316,7 @@ static struct ref *do_fetch_pack_v2(struct 
> fetch_pack_args *args,
>   continue;
>   }
>   }
> + negotiator.release();
>  
>   oidset_clear();

nit: could put the negotiator.release() after the blank
line, in the same paragraph as the other free calls like
oidset_clear().

[...]
> +++ b/negotiator/default.c
> @@ -0,0 +1,173 @@
> +#include "default.h"

First #include should be "git-compat-util.h".

[...]
> +/*
> +   This function marks a rev and its ancestors as common.
> +   In some cases, it is desirable to mark only the ancestors (for example
> +   when only the server does not yet know that they are common).
> +*/