Add a convenience function to wrap the xsnprintf() command that generates loose object headers. This code was copy/pasted in various parts of the codebase, let's define it in one place and re-use it from there. All except one caller of it had a valid "enum object_type" for us, it's only write_object_file_prepare() which might need to deal with "git hash-object --literally" and a potential garbage type. Let's have the primary API use an "enum object_type", and define an *_extended() function that can take an arbitrary "const char *" for the type. See [1] for the discussion that prompted this patch, i.e. new code in object-file.c that wanted to copy/paste the xsnprintf() invocation. 1. https://lore.kernel.org/git/211213.86bl1l9bfz.gmgdl@xxxxxxxxxxxxxxxxxxx/ Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> --- On Fri, Dec 17 2021, Han Xin wrote: > From: Han Xin <hanxin.hx@xxxxxxxxxxxxxxx> > > There are 3 places where "xsnprintf" is used to generate the object > header, and I originally planned to add a fourth in the latter patch. > > According to Ævar Arnfjörð Bjarmason’s suggestion, although it's just > one line, it's also code that's very central to git, so reafactor them > into a function which will help later readability. > > Helped-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> > Signed-off-by: Han Xin <hanxin.hx@xxxxxxxxxxxxxxx> I came up with this after my comment on the earlier round suggesting to factor out that header formatting. I don't know if this more thorough approach is worth it or if you'd like to replace your change with this one, but just posting it here as an RFC. builtin/index-pack.c | 3 +-- bulk-checkin.c | 4 ++-- cache.h | 21 +++++++++++++++++++++ http-push.c | 2 +- object-file.c | 14 +++++++++++--- 5 files changed, 36 insertions(+), 8 deletions(-) diff --git a/builtin/index-pack.c b/builtin/index-pack.c index c23d01de7dc..900c6539f68 100644 --- a/builtin/index-pack.c +++ b/builtin/index-pack.c @@ -449,8 +449,7 @@ static void *unpack_entry_data(off_t offset, unsigned long size, int hdrlen; if (!is_delta_type(type)) { - hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX, - type_name(type),(uintmax_t)size) + 1; + hdrlen = format_loose_header(hdr, sizeof(hdr), type, (uintmax_t)size); the_hash_algo->init_fn(&c); the_hash_algo->update_fn(&c, hdr, hdrlen); } else diff --git a/bulk-checkin.c b/bulk-checkin.c index 8785b2ac806..446dea7c516 100644 --- a/bulk-checkin.c +++ b/bulk-checkin.c @@ -220,8 +220,8 @@ static int deflate_to_pack(struct bulk_checkin_state *state, if (seekback == (off_t) -1) return error("cannot find the current offset"); - header_len = xsnprintf((char *)obuf, sizeof(obuf), "%s %" PRIuMAX, - type_name(type), (uintmax_t)size) + 1; + header_len = format_loose_header((char *)obuf, sizeof(obuf), + type, (uintmax_t)size); the_hash_algo->init_fn(&ctx); the_hash_algo->update_fn(&ctx, obuf, header_len); diff --git a/cache.h b/cache.h index d5cafba17d4..ccece21a4a2 100644 --- a/cache.h +++ b/cache.h @@ -1309,6 +1309,27 @@ enum unpack_loose_header_result unpack_loose_header(git_zstream *stream, unsigned long bufsiz, struct strbuf *hdrbuf); +/** + * format_loose_header() is a thin wrapper around s xsnprintf() that + * writes the initial "<type> <obj-len>" part of the loose object + * header. It returns the size that snprintf() returns + 1. + * + * The format_loose_header_extended() function allows for writing a + * type_name that's not one of the "enum object_type" types. This is + * used for "git hash-object --literally". Pass in a OBJ_NONE as the + * type, and a non-NULL "type_str" to do that. + * + * format_loose_header() is a convenience wrapper for + * format_loose_header_extended(). + */ +int format_loose_header_extended(char *str, size_t size, enum object_type type, + const char *type_str, size_t objsize); +static inline int format_loose_header(char *str, size_t size, + enum object_type type, size_t objsize) +{ + return format_loose_header_extended(str, size, type, NULL, objsize); +} + /** * parse_loose_header() parses the starting "<type> <len>\0" of an * object. If it doesn't follow that format -1 is returned. To check diff --git a/http-push.c b/http-push.c index 3309aaf004a..d1a8619e0af 100644 --- a/http-push.c +++ b/http-push.c @@ -363,7 +363,7 @@ static void start_put(struct transfer_request *request) git_zstream stream; unpacked = read_object_file(&request->obj->oid, &type, &len); - hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX , type_name(type), (uintmax_t)len) + 1; + hdrlen = format_loose_header(hdr, sizeof(hdr), type, (uintmax_t)len); /* Set it up */ git_deflate_init(&stream, zlib_compression_level); diff --git a/object-file.c b/object-file.c index eac67f6f5f9..d94609ee48d 100644 --- a/object-file.c +++ b/object-file.c @@ -1009,6 +1009,14 @@ void *xmmap(void *start, size_t length, return ret; } +int format_loose_header_extended(char *str, size_t size, enum object_type type, + const char *typestr, size_t objsize) +{ + const char *s = type == OBJ_NONE ? typestr : type_name(type); + + return xsnprintf(str, size, "%s %"PRIuMAX, s, (uintmax_t)objsize) + 1; +} + /* * With an in-core object data in "map", rehash it to make sure the * object name actually matches "oid" to detect object corruption. @@ -1037,7 +1045,7 @@ int check_object_signature(struct repository *r, const struct object_id *oid, return -1; /* Generate the header */ - hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX , type_name(obj_type), (uintmax_t)size) + 1; + hdrlen = format_loose_header(hdr, sizeof(hdr), obj_type, size); /* Sha1.. */ r->hash_algo->init_fn(&c); @@ -1737,7 +1745,7 @@ static void write_object_file_prepare(const struct git_hash_algo *algo, git_hash_ctx c; /* Generate the header */ - *hdrlen = xsnprintf(hdr, *hdrlen, "%s %"PRIuMAX , type, (uintmax_t)len)+1; + *hdrlen = format_loose_header_extended(hdr, *hdrlen, OBJ_NONE, type, len); /* Sha1.. */ algo->init_fn(&c); @@ -2009,7 +2017,7 @@ int force_object_loose(const struct object_id *oid, time_t mtime) buf = read_object(the_repository, oid, &type, &len); if (!buf) return error(_("cannot read object for %s"), oid_to_hex(oid)); - hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX , type_name(type), (uintmax_t)len) + 1; + hdrlen = format_loose_header(hdr, sizeof(hdr), type, len); ret = write_loose_object(oid, hdr, hdrlen, buf, len, mtime, 0); free(buf); -- 2.34.1.1119.g606023410ba
