Re: [PATCH v2] receive-pack.c: consolidate find header logic
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Dec 30, 2021, 23:01 UTC
- Message-ID
- <xmqq1r1tofyf.fsf@gitster.g>
- In-Reply-To
- <pull.1125.v2.git.git.1640758765723.gitgitgadget@gmail.com>
"John Cai via GitGitGadget" <gitgitgadget@gmail.com> writes:
Show 10 quoted lines
> From: John Cai <johncai86@gmail.com> > > There are two functions that have very similar logic of finding a header > value. find_commit_header, and find_header. We can conslidate the logic > by using find_commit_header and replacing the logic in find_header. > > Introduce a new function find_header_max, which is equivalent to > find_commit_header except it takes a len parameter that determines how > many bytes to read. find_commit_header can then call find_header_max > with 0 as the len.
find_header_max() is not the name of the function that finds the largest header? That is misleading.
<git-compat-util.h> defines a few helper functions that take a counted string, and they are named with _mem() suffix after the name of their NUL-terminated counterparts (if exists). skip_prefix() has skip_prefix_mem(), strip_suffix() has strip_suffix_mem().
find_header_mem() or something along that line, perhaps?
Show 12 quoted lines
> diff --git a/commit.c b/commit.c > index a348f085b2b..2ed115e04a0 100644 > --- a/commit.c > +++ b/commit.c > @@ -1631,12 +1631,14 @@ struct commit_list **commit_list_append(struct commit *commit, > return &new_commit->next; > } > > -const char *find_commit_header(const char *msg, const char *key, size_t *out_len) > +const char *find_header_max(const char *msg, const char *key, > + size_t len, > + size_t *out_len)
If <len> is meant to be the length part of <ptr,len> pair, we should have it immediately after the <ptr> parameter.
find_header_mem(const char *msg, size_t len,
const char *key, size_t *out_len)That makes it clear to the readers that <msg, len> are close friends.
Also, I have a feeling that ...
Show 6 quoted lines
> {
> int key_len = strlen(key);
> const char *line = msg;
>
> - while (line) {
> + while (line && (len == 0 || line < msg + len)) {... we do not want this special casing of "if !len". By making the caller responsible to _always_ supply the length of msg, we can lose the conditional.
Show 10 quoted lines
> const char *eol = strchrnul(line, '\n');
>
> if (line == eol)
> @@ -1653,6 +1655,10 @@ const char *find_commit_header(const char *msg, const char *key, size_t *out_len
> return NULL;
> }
>
> +const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
> +{
> + return find_header_max(msg, key, 0, out_len);I.e. find_header_mem(msg, strlen(msg), key, out_len);
Show 27 quoted lines
> diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
> index 9f4a0b816cf..b69ead8dcda 100644
> --- a/builtin/receive-pack.c
> +++ b/builtin/receive-pack.c
> @@ -581,32 +581,19 @@ static char *prepare_push_cert_nonce(const char *path, timestamp_t stamp)
> return strbuf_detach(&buf, NULL);
> }
>
> -/*
> - * NEEDSWORK: reuse find_commit_header() from jk/commit-author-parsing
> - * after dropping "_commit" from its name and possibly moving it out
> - * of commit.c
> - */
> static char *find_header(const char *msg, size_t len, const char *key,
> const char **next_line)
> {
> + size_t out_len;
> + const char *val = find_header_max(msg, key, len, &out_len);
> +
> + if (val == NULL)
> + return NULL;
> +
> + if (next_line)
> + *next_line = val + out_len + 1;
> +
> + return xmemdupz(val, out_len);
> }Yup, something along that line. Note that find_header() does make it clear that the <msg, len> parameters form a pair. We want to do the same for the new helper.