From: Ben Peart <peartben@gmail.com>
To: "Martin Ågren" <martin.agren@gmail.com>,
"Ben Peart" <Ben.Peart@microsoft.com>
Cc: "git@vger.kernel.org" <git@vger.kernel.org>,
"pclouds@gmail.com" <pclouds@gmail.com>,
"alexmv@dropbox.com" <alexmv@dropbox.com>,
"blees@dcon.de" <blees@dcon.de>,
"gitster@pobox.com" <gitster@pobox.com>,
"bmwill@google.com" <bmwill@google.com>,
"avarab@gmail.com" <avarab@gmail.com>,
"johannes.schindelin@gmx.de" <johannes.schindelin@gmx.de>
Subject: Re: [PATCH v1 1/2] fsexcludes: add a programmatic way to exclude files from git's working directory traversal logic
Date: Wed, 11 Apr 2018 15:56:35 -0400 [thread overview]
Message-ID: <082cda6c-eb9f-c853-c09b-e0d3bc04cb9c@gmail.com> (raw)
In-Reply-To: <CAN0heSpKzG93OcAAAoHQxURVGsHFWz6j494C+3bezHLTOovQHA@mail.gmail.com>
On 4/10/2018 6:09 PM, Martin Ågren wrote:
> On 10 April 2018 at 23:04, Ben Peart <Ben.Peart@microsoft.com> wrote:
>> The File System Excludes module is a new programmatic way to exclude files and
>> folders from git's traversal of the working directory. fsexcludes_init() should
>> be called with a string buffer that contains a NUL separated list of path names
>> of the files and/or directories that should be included. Any path not listed
>> will be excluded. The paths should be relative to the root of the working
>> directory and be separated by a single NUL.
>>
>> The excludes logic in dir.c has been updated to honor the results of
>> fsexcludes_is_excluded_from(). If fsexcludes does not exclude the file, the
>> normal excludes logic is also checked as it could further reduce the set of
>> files that should be included.
>
> Here you mention a change in dir.c...
>
>> Makefile | 1 +
>> fsexcludes.c | 210 +++++++++++++++++++++++++++++++++++++++++++++++++++
>> fsexcludes.h | 27 +++++++
>> 3 files changed, 238 insertions(+)
>
> ... but this patch does not seem to touch dir.c at all.
>
Oops! Fixed in V2.
>> +static int check_fsexcludes_hashmap(struct hashmap *map, const char *pattern, int patternlen)
>> +{
>> + struct strbuf sb = STRBUF_INIT;
>> + struct fsexcludes fse;
>> + char *slash;
>> +
>> + /* Check straight mapping */
>> + strbuf_reset(&sb);
>
> You could drop this strbuf_reset(). Or did you intend to use a static
> struct strbuf?
>
Good point, fixed in V2.
>> + /*
>> + * Check to see if it matches a directory or any path
>> + * underneath it. In other words, 'a/b/foo.txt' will match
>> + * '/', 'a/', and 'a/b/'.
>> + */
>> + slash = strchr(sb.buf, '/');
>> + while (slash) {
>> + fse.pattern = sb.buf;
>> + fse.patternlen = slash - sb.buf + 1;
>> + hashmap_entry_init(&fse, fsexcludeshash(fse.pattern, fse.patternlen));
>> + if (hashmap_get(map, &fse, NULL)) {
>> + strbuf_release(&sb);
>> + return 0;
>> + }
>> + slash = strchr(slash + 1, '/');
>> + }
>
> Maybe a for-loop would make this slightly more obvious:
>
> for (slash = strchr(sb.buf, '/'); slash; slash = strchr(slash + 1, '/'))
>
> On second thought, maybe not.
>
>> + entry = buf = fsexcludes_data->buf;
>> + len = fsexcludes_data->len;
>> + for (i = 0; i < len; i++) {
>> + if (buf[i] == '\0') {
>> + fsexcludes_hashmap_add(map, entry, buf + i - entry);
>> + entry = buf + i + 1;
>> + }
>> + }
>> +}
>
> Very minor: I would have found "buf - entry + i" clearer here and later,
> but I'm sure you'll find someone of the opposing opinion (e.g.,
> yourself). ;-)
>
>> +static int check_directory_hashmap(struct hashmap *map, const char *pathname, int pathlen)
>> +{
>> + struct strbuf sb = STRBUF_INIT;
>> + struct fsexcludes fse;
>> +
>> + /* Check for directory */
>> + strbuf_reset(&sb);
>
> Same comment as above about this spurious reset.
Good point, fixed in V2.
>
>> + if (hashmap_get(map, &fse, NULL)) {
>> + strbuf_release(&sb);
>> + return 0;
>> + }
>> +
>> + strbuf_release(&sb);
>> + return 1;
>> +}
>> +
>> +/*
>> + * Return 1 for exclude, 0 for include and -1 for undecided.
>> + */
>> +int fsexcludes_is_excluded_from(struct index_state *istate,
>> + const char *pathname, int pathlen, int dtype)
>> +{
>
> Will we at some point regret not being able to "return negative on
> error"? I guess that would be "-2" or "negative other than -1".
>
This function is modeled after the other is_excluded_from* functions in
dir.c so that the return value can be handled the same way. I don't
anticipate any need for change but you're right, we could return some
other "negative other than -1" if it was ever needed.
>> +void fsexcludes_init(struct strbuf *sb) {
>> + fsexcludes_initialized = 1;
>> + fsexcludes_data = *sb;
>> +}
>
> Grabbing the strbuf's members looks a bit odd. Is this
> performance-sensitive enough that you do not want to make a copy? If a
> caller releases its strbuf, which would normally be a good thing to do,
> we may be in big trouble later. (Not only may .buf be stale, .len may
> indicate we actually have something to read.)
>
> I can understand that you do not want to pass a pointer+len, and that it
> is not enough to pass sb.buf, since the string may contain nuls.
>
> Maybe detach the original strbuf? That way, if a caller releases its
> buffer, that is a no-op. A caller which goes on to use its buffer should
> fail quickly and obviously. Right now, an incorrect caller would
> probably fail more subtly and less reproducibly.
>
> In any case, maybe document this in the .h-file?
Great suggestion! I was looking for a better way to ensure the buffer
ownership transfer was robust. I'll do both strbuf_detach() and update
the header file. Thank you.
>
> Martin
>
next prev parent reply other threads:[~2018-04-11 19:56 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-10 21:04 [PATCH v1 0/2] fsexcludes: Add programmatic way to exclude files Ben Peart
2018-04-10 21:04 ` [PATCH v1 1/2] fsexcludes: add a programmatic way to exclude files from git's working directory traversal logic Ben Peart
2018-04-10 22:09 ` Martin Ågren
2018-04-11 19:56 ` Ben Peart [this message]
2018-04-11 6:58 ` Junio C Hamano
2018-04-10 21:04 ` [PATCH v1 2/2] fsmonitor: switch to use new fsexcludes logic and remove unused untracked cache based logic Ben Peart
2018-04-11 20:01 ` [PATCH v2 0/2] fsexcludes: Add programmatic way to exclude files Ben Peart
2018-04-11 20:01 ` [PATCH v2 1/2] fsexcludes: add a programmatic way to exclude files from git's working directory traversal logic Ben Peart
2018-04-11 23:52 ` Junio C Hamano
2018-04-13 11:53 ` Ben Peart
2018-04-11 20:01 ` [PATCH v2 2/2] fsmonitor: switch to use new fsexcludes logic and remove unused untracked cache based logic Ben Peart
2018-04-13 12:22 ` [PATCH v3 0/2] fsexcludes: Add programmatic way to exclude files Ben Peart
2018-04-13 12:22 ` [PATCH v3 1/2] fsexcludes: add a programmatic way to exclude files from git's working directory traversal logic Ben Peart
2018-04-13 12:22 ` [PATCH v3 2/2] fsmonitor: switch to use new fsexcludes logic and remove unused untracked cache based logic Ben Peart
2018-04-18 15:31 ` [PATCH v3 0/2] fsexcludes: Add programmatic way to exclude files Ben Peart
2018-04-18 21:25 ` Junio C Hamano
2018-04-14 15:59 ` [PATCH v1 " Duy Nguyen
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