object-file API: add a format_object_header() function
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 a *_literally() 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. In the case of fast-import.c the callers unfortunately need to cast back & forth between "unsigned char *" and "char *", since format_object_header() ad encode_in_pack_object_header() take different signedness. 1. https://lore.kernel.org/git/211213.86bl1l9bfz.gmgdl@evledraar.gmail.com/ Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Ævar Arnfjörð Bjarmason committed
Feb 5, 2022 at 00:48 UTC
b04cdea46cf5ae60066fa6dd12d5449bf3ef283f
6 files changed
+35
-11
builtin/fast-import.c
+3
-3
@@ -937,8 +937,8 @@ static int store_object(
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git_hash_ctx c;
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git_zstream s;
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- hdrlen = xsnprintf((char *)hdr, sizeof(hdr), "%s %lu",
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- type_name(type), (unsigned long)dat->len) + 1;
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+ hdrlen = format_object_header((char *)hdr, sizeof(hdr), type,
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+ dat->len);
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the_hash_algo->init_fn(&c);
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the_hash_algo->update_fn(&c, hdr, hdrlen);
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the_hash_algo->update_fn(&c, dat->buf, dat->len);
@@ -1091,7 +1091,7 @@ static void stream_blob(uintmax_t len, struct object_id *oidout, uintmax_t mark)
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hashfile_checkpoint(pack_file, &checkpoint);
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offset = checkpoint.offset;
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- hdrlen = xsnprintf((char *)out_buf, out_sz, "blob %" PRIuMAX, len) + 1;
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+ hdrlen = format_object_header((char *)out_buf, out_sz, OBJ_BLOB, len);
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the_hash_algo->init_fn(&c);
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the_hash_algo->update_fn(&c, out_buf, hdrlen);
builtin/index-pack.c
+1
-2
@@ -449,8 +449,7 @@ static void *unpack_entry_data(off_t offset, unsigned long size,
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int hdrlen;
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if (!is_delta_type(type)) {
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- hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX,
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- type_name(type),(uintmax_t)size) + 1;
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+ hdrlen = format_object_header(hdr, sizeof(hdr), type, size);
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the_hash_algo->init_fn(&c);
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the_hash_algo->update_fn(&c, hdr, hdrlen);
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} else
bulk-checkin.c
+2
-2
@@ -220,8 +220,8 @@ static int deflate_to_pack(struct bulk_checkin_state *state,
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if (seekback == (off_t) -1)
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return error("cannot find the current offset");
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- header_len = xsnprintf((char *)obuf, sizeof(obuf), "%s %" PRIuMAX,
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- type_name(type), (uintmax_t)size) + 1;
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+ header_len = format_object_header((char *)obuf, sizeof(obuf),
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+ type, size);
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the_hash_algo->init_fn(&ctx);
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the_hash_algo->update_fn(&ctx, obuf, header_len);
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http-push.c
+1
-1
@@ -363,7 +363,7 @@ static void start_put(struct transfer_request *request)
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git_zstream stream;
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unpacked = read_object_file(&request->obj->oid, &type, &len);
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- hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX , type_name(type), (uintmax_t)len) + 1;
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+ hdrlen = format_object_header(hdr, sizeof(hdr), type, len);
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/* Set it up */
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git_deflate_init(&stream, zlib_compression_level);
object-file.c
+20
-3
@@ -1049,6 +1049,23 @@ void *xmmap(void *start, size_t length,
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return ret;
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}
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+static int format_object_header_literally(char *str, size_t size,
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+ const char *type, size_t objsize)
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+{
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+ return xsnprintf(str, size, "%s %"PRIuMAX, type, (uintmax_t)objsize) + 1;
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+}
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+
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+int format_object_header(char *str, size_t size, enum object_type type,
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+ size_t objsize)
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+{
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+ const char *name = type_name(type);
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+
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+ if (!name)
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+ BUG("could not get a type name for 'enum object_type' value %d", type);
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+
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+ return format_object_header_literally(str, size, name, objsize);
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+}
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+
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/*
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* With an in-core object data in "map", rehash it to make sure the
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* object name actually matches "oid" to detect object corruption.
@@ -1077,7 +1094,7 @@ int check_object_signature(struct repository *r, const struct object_id *oid,
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return -1;
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/* Generate the header */
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- hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX , type_name(obj_type), (uintmax_t)size) + 1;
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+ hdrlen = format_object_header(hdr, sizeof(hdr), obj_type, size);
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/* Sha1.. */
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r->hash_algo->init_fn(&c);
@@ -1777,7 +1794,7 @@ static void write_object_file_prepare(const struct git_hash_algo *algo,
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git_hash_ctx c;
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/* Generate the header */
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- *hdrlen = xsnprintf(hdr, *hdrlen, "%s %"PRIuMAX , type, (uintmax_t)len)+1;
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+ *hdrlen = format_object_header_literally(hdr, *hdrlen, type, len);
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/* Sha1.. */
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algo->init_fn(&c);
@@ -2051,7 +2068,7 @@ int force_object_loose(const struct object_id *oid, time_t mtime)
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buf = read_object(the_repository, oid, &type, &len);
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if (!buf)
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return error(_("cannot read object for %s"), oid_to_hex(oid));
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- hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX , type_name(type), (uintmax_t)len) + 1;
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+ hdrlen = format_object_header(hdr, sizeof(hdr), type, len);
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ret = write_loose_object(oid, hdr, hdrlen, buf, len, mtime, 0);
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free(buf);
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object-store.h
+8
@@ -331,6 +331,14 @@ int repo_has_object_file_with_flags(struct repository *r,
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*/
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int has_loose_object_nonlocal(const struct object_id *);
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+/**
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+ * format_object_header() is a thin wrapper around s xsnprintf() that
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+ * writes the initial "<type> <obj-len>" part of the loose object
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+ * header. It returns the size that snprintf() returns + 1.
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+ */
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+int format_object_header(char *str, size_t size, enum object_type type,
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+ size_t objsize);
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+
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void assert_oid_type(const struct object_id *oid, enum object_type expect);
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/*