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From: Derrick Stolee <stolee@gmail.com>
To: Taylor Blau <me@ttaylorr.com>, Junio C Hamano <gitster@pobox.com>
Cc: Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org, jnareb@gmail.com, garimasigit@gmail.com,
	Derrick Stolee <dstolee@microsoft.com>
Subject: Re: [PATCH 1/3] revision: complicated pathspecs disable filters
Date: Mon, 13 Apr 2020 07:54:48 -0400	[thread overview]
Message-ID: <4a3af6a9-50ef-1759-7e4c-56f6c5af542a@gmail.com> (raw)
In-Reply-To: <20200413000748.GA55122@syl.local>

On 4/12/2020 8:07 PM, Taylor Blau wrote:
> On Sun, Apr 12, 2020 at 03:30:07PM -0700, Junio C Hamano wrote:
>> Taylor Blau <me@ttaylorr.com> writes:
>>
>>> I certainly wouldn't complain about a comment here explaining these
>>> three checks, but I suppose that the rationale is only a 'git blame'
>>> away (and I guess that is faster now after this series ;-)).
>>>
>>>> +	if (revs->prune_data.has_wildcard)
>>>> +		return;
>>>> +	if (revs->prune_data.nr > 1)
>>>> +		return;
>>>> +	if (revs->prune_data.magic ||
>>>> +	    (revs->prune_data.nr &&
>>>> +	     revs->prune_data.items[0].magic))
>>
>> This says "any magic", but it is overly pessimistic to disable the
>> optimization for "literal" magic.  That magic is the one that lets
>> well written scripts to say "I have in a '$variable' that the user
>> gave me as a pathname (not pathspec), and it may have a wildcard
>> letter in it, but please treat it as a literal string" by prefixing
>> ":(literal)" before that user-supplied data, so it is punishing well
>> disciplined folks.

This is a good point. I'm unfamiliar with these advanced pathspec
tricks.

> I hadn't thought of that, but it makes sense to me. How about something
> like this squashed into this patch? I moved the if-chain that Stolee
> introduced out to its own function, at least since they seem
> well-contained and related to one another. I figure that this simplifies
> the implementation of 'prepare_to_use_bloom_filter' by giving the reader
> less to think about up-front.
> 
> diff --git a/revision.c b/revision.c
> index 534c0bf996..15bf4ccff5 100644
> --- a/revision.c
> +++ b/revision.c
> @@ -654,6 +654,18 @@ static void trace2_bloom_filter_statistics_atexit(void)
>         jw_release(&jw);
>  }
> 
> +static int has_bloom_key(struct pathspec *spec)
> +{
> +       if (spec->has_wildcard)
> +               return 0;
> +       if (spec->nr > 1)
> +               return 0;
> +       if ((spec->magic & ~PATHSPEC_LITERAL) ||
> +           (spec->nr && spec->items[0].magic & ~PATHSPEC_LITERAL))
> +               return 0;
> +       return 1;
> +}
> +

Perhaps flip this on its head?

+static int forbids_bloom_key(struct pathspec *spec)
+{
+       if (spec->has_wildcard)
+               return 1;
+       if (spec->nr > 1)
+               return 1;
+       if (spec->magic & ~PATHSPEC_LITERAL)
+		return 1;
+	if (spec->nr && (spec->items[0].magic & ~PATHSPEC_LITERAL))
+               return 1;
+       return 0;
+}
+

>  static void prepare_to_use_bloom_filter(struct rev_info *revs)
>  {
>         struct pathspec_item *pi;
> @@ -665,13 +677,7 @@ static void prepare_to_use_bloom_filter(struct rev_info *revs)
>         if (!revs->commits)
>             return;
> 
> -       if (revs->prune_data.has_wildcard)
> -               return;
> -       if (revs->prune_data.nr > 1)
> -               return;
> -       if (revs->prune_data.magic ||
> -           (revs->prune_data.nr &&
> -            revs->prune_data.items[0].magic))
> +       if (!has_bloom_key(&revs->prune_data))
>                 return;

Then this would be "if (forbids_bloom_key(&revs->prune_data))"

Generally, I like pulling this stuff out as a method to isolate and
label its purpose. If we wanted to allow certain :(icase) things
later, then we know what to modify in order to "allow" it.

Thanks,
-Stolee

  reply	other threads:[~2020-04-13 11:59 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-11  1:02 [PATCH 0/3] Integrate changed-path Bloom filters with 'git blame' Derrick Stolee via GitGitGadget
2020-04-11  1:02 ` [PATCH 1/3] revision: complicated pathspecs disable filters Derrick Stolee via GitGitGadget
2020-04-11 21:40   ` Junio C Hamano
2020-04-13 11:49     ` Derrick Stolee
2020-04-14 18:25       ` Junio C Hamano
2020-04-15 13:27         ` Derrick Stolee
2020-04-15 18:37           ` Derrick Stolee
2020-04-15 19:32             ` Junio C Hamano
2020-04-15 19:39               ` Junio C Hamano
2020-04-15 21:25             ` Junio C Hamano
2020-04-16  0:56               ` Taylor Blau
2020-04-15 22:18             ` Jakub Narębski
2020-04-16  0:52               ` Taylor Blau
2020-04-16 13:26                 ` Derrick Stolee
2020-04-16 16:33                   ` Taylor Blau
2020-04-16 18:02                     ` Junio C Hamano
2020-04-12 22:22   ` Taylor Blau
2020-04-12 22:30     ` Junio C Hamano
2020-04-13  0:07       ` Taylor Blau
2020-04-13 11:54         ` Derrick Stolee [this message]
2020-04-11  1:03 ` [PATCH 2/3] commit: write commit-graph with bloom filters Derrick Stolee via GitGitGadget
2020-04-11 21:57   ` Junio C Hamano
2020-04-12 20:51     ` Taylor Blau
2020-04-13 12:08       ` Derrick Stolee
2020-04-13 22:11         ` Junio C Hamano
2020-04-11  1:03 ` [PATCH 3/3] blame: use changed-path Bloom filters Derrick Stolee via GitGitGadget
2020-04-11 22:03   ` Junio C Hamano
2020-04-12  7:39     ` Eric Sunshine
2020-04-11 21:30 ` [PATCH 0/3] Integrate changed-path Bloom filters with 'git blame' Junio C Hamano
2020-04-13 14:45 ` [PATCH v2 0/4] " Derrick Stolee via GitGitGadget
2020-04-13 14:45   ` [PATCH v2 1/4] revision: complicated pathspecs disable filters Derrick Stolee via GitGitGadget
2020-04-13 16:09     ` Taylor Blau
2020-04-13 22:18       ` Junio C Hamano
2020-04-13 14:45   ` [PATCH v2 2/4] commit: write commit-graph with Bloom filters Derrick Stolee via GitGitGadget
2020-04-13 16:12     ` Taylor Blau
2020-04-13 22:21       ` Junio C Hamano
2020-04-14 15:04         ` Derrick Stolee
2020-04-14 17:26           ` Junio C Hamano
2020-04-14 17:40             ` Derrick Stolee
2020-04-15  0:17               ` Taylor Blau
2020-04-13 14:45   ` [PATCH v2 3/4] commit-graph: write commit-graph in more tests Derrick Stolee via GitGitGadget
2020-04-13 14:45   ` [PATCH v2 4/4] blame: use changed-path Bloom filters Derrick Stolee via GitGitGadget
2020-04-13 16:21   ` [PATCH v2 0/4] Integrate changed-path Bloom filters with 'git blame' Taylor Blau
2020-04-16 20:14   ` [PATCH v3 0/3] " Derrick Stolee via GitGitGadget
2020-04-16 20:14     ` [PATCH v3 1/3] revision: complicated pathspecs disable filters Derrick Stolee via GitGitGadget
2020-06-07 20:33       ` SZEDER Gábor
2020-04-16 20:14     ` [PATCH v3 2/3] tests: write commit-graph with Bloom filters Derrick Stolee via GitGitGadget
2020-04-16 20:14     ` [PATCH v3 3/3] blame: use changed-path " Derrick Stolee via GitGitGadget

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