Re: [PATCH 2/2] commit: don't check for space twice when looking for header
Am 27.02.2017 um 23:27 schrieb Jakub Narębski:
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> W dniu 25.02.2017 o 20:27, René Scharfe pisze:
>> Both standard_header_field() and excluded_header_field() check if
>> there's a space after the buffer that's handed to them. We already
>> check in the caller if that space is present. Don't bother calling
>> the functions if it's missing, as they are guaranteed to return 0 in
>> that case, and remove the now redundant checks from them.
>>
>> Signed-off-by: Rene Scharfe <l.s.r@web.de>
>> ---
>> commit.c | 18 ++++++++----------
>> 1 file changed, 8 insertions(+), 10 deletions(-)
>>
>> diff --git a/commit.c b/commit.c
>> index 173c6d3818..fab8269731 100644
>> --- a/commit.c
>> +++ b/commit.c
>> @@ -1308,11 +1308,11 @@ void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
>>
>> static inline int standard_header_field(const char *field, size_t len)
>> {
>> - return ((len == 4 && !memcmp(field, "tree ", 5)) ||
>> - (len == 6 && !memcmp(field, "parent ", 7)) ||
>> - (len == 6 && !memcmp(field, "author ", 7)) ||
>> - (len == 9 && !memcmp(field, "committer ", 10)) ||
>> - (len == 8 && !memcmp(field, "encoding ", 9)));
>> + return ((len == 4 && !memcmp(field, "tree", 4)) ||
>> + (len == 6 && !memcmp(field, "parent", 6)) ||
>> + (len == 6 && !memcmp(field, "author", 6)) ||
>> + (len == 9 && !memcmp(field, "committer", 9)) ||
>> + (len == 8 && !memcmp(field, "encoding", 8)));
>
> I agree (for what it is worth from me) with the rest of changes,
> but I think current code is better self-documenting for this
> function.Having a function that is given a buffer/length pair and accessing the byte after it raises questions, though. :)
Nicer than keeping the space would be to use excluded_header_field() for standard headers as well as a next step, I think -- but that would be a bit slower.
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>
>> }
>>
>> static int excluded_header_field(const char *field, size_t len, const char **exclude)
>> @@ -1322,8 +1322,7 @@ static int excluded_header_field(const char *field, size_t len, const char **exc
>>
>> while (*exclude) {
>> size_t xlen = strlen(*exclude);
>> - if (len == xlen &&
>> - !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
>> + if (len == xlen && !memcmp(field, *exclude, xlen))
>> return 1;
>> exclude++;
>> }
>> @@ -1357,9 +1356,8 @@ static struct commit_extra_header *read_commit_extra_header_lines(
>> eof = memchr(line, ' ', next - line);
>> if (!eof)
>> eof = next;
>> -
>> - if (standard_header_field(line, eof - line) ||
>> - excluded_header_field(line, eof - line, exclude))
>> + else if (standard_header_field(line, eof - line) ||
>> + excluded_header_field(line, eof - line, exclude))
>> continue;
>>
>> it = xcalloc(1, sizeof(*it));
>>
>
René Scharfe
