Am 01.11.2017 um 23:15 schrieb Jeff King:
> On Wed, Nov 01, 2017 at 10:59:49PM +0100, René Scharfe wrote:
>
>>> The hex_to_bytes() function requires that the caller make sure they have
>>> the right number of bytes. But for many callers, I think they'd want to
>>> say "parse this oid, which might be truncated; I can't tell what the
>>> length is supposed to be".
>>
>> I'm confused by the word "many". After this series there are three
>> callers of hex_to_bytes() and I don't expect that number to grow.
>
> I meant only that most callers that parse oids, both in-file and not,
> would want to stop knowing about the length ahead of time.
That's a good idea.
> I'm not sure we know 100%
> yet what "new"-style hashes will look like, nor how their loose-object
> filenames would look.
So it's too early to implement a solution, but here's how a patch for
reducing dependency on hash lengths could look like today:
---
cache.h | 2 ++
hex.c | 13 +++++++++++++
http-push.c | 7 +++----
notes.c | 6 +-----
sha1_file.c | 4 +---
5 files changed, 20 insertions(+), 12 deletions(-)
diff --git a/cache.h b/cache.h
index f06bfbaf32..acd3804c21 100644
--- a/cache.h
+++ b/cache.h
@@ -1317,6 +1317,8 @@ extern int set_disambiguate_hint_config(const char *var, const char *value);
extern int get_sha1_hex(const char *hex, unsigned char *sha1);
extern int get_oid_hex(const char *hex, struct object_id *sha1);
+extern int get_oid_hex_tail(const char *hex, struct object_id *oid, size_t offset);
+
/*
* Read `len` pairs of hexadecimal digits from `hex` and write the
* values to `binary` as `len` bytes. Return 0 on success, or -1 if
diff --git a/hex.c b/hex.c
index 8df2d63728..3e6abe4d5e 100644
--- a/hex.c
+++ b/hex.c
@@ -47,6 +47,19 @@ int hex_to_bytes(unsigned char *binary, const char *hex, size_t len)
return 0;
}
+int get_oid_hex_tail(const char *hex, struct object_id *oid, size_t offset)
+{
+ for (; offset < GIT_SHA1_RAWSZ; offset++, hex += 2) {
+ int val = hex2chr(hex);
+ if (val < 0)
+ return -1;
+ oid->hash[offset] = val;
+ }
+ if (*hex)
+ return -1;
+ return 0;
+}
+
int get_sha1_hex(const char *hex, unsigned char *sha1)
{
int i;
diff --git a/http-push.c b/http-push.c
index 14435ab65d..a5512616b9 100644
--- a/http-push.c
+++ b/http-push.c
@@ -1007,18 +1007,17 @@ static void remote_ls(const char *path, int flags,
void (*userFunc)(struct remote_ls_ctx *ls),
void *userData);
-/* extract hex from sharded "xx/x{38}" filename */
+/* extract hex from sharded "xx/x{N}" filename */
static int get_oid_hex_from_objpath(const char *path, struct object_id *oid)
{
- if (strlen(path) != GIT_SHA1_HEXSZ + 1)
+ if (strnlen(path, 3) < 3)
return -1;
-
if (hex_to_bytes(oid->hash, path, 1))
return -1;
path += 2;
path++; /* skip '/' */
- return hex_to_bytes(oid->hash + 1, path, GIT_SHA1_RAWSZ - 1);
+ return get_oid_hex_tail(path, oid, 1);
}
static void process_ls_object(struct remote_ls_ctx *ls)
diff --git a/notes.c b/notes.c
index 04f8c8613c..ff6ce57022 100644
--- a/notes.c
+++ b/notes.c
@@ -410,17 +410,13 @@ static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
struct leaf_node *l;
size_t path_len = strlen(entry.path);
- if (path_len == 2 * (GIT_SHA1_RAWSZ - prefix_len)) {
+ if (!get_oid_hex_tail(entry.path, &object_oid, prefix_len)) {
/* This is potentially the remainder of the SHA-1 */
if (!S_ISREG(entry.mode))
/* notes must be blobs */
goto handle_non_note;
- if (hex_to_bytes(object_oid.hash + prefix_len, entry.path,
- GIT_SHA1_RAWSZ - prefix_len))
- goto handle_non_note; /* entry.path is not a SHA1 */
-
type = PTR_TYPE_NOTE;
} else if (path_len == 2) {
/* This is potentially an internal node */
diff --git a/sha1_file.c b/sha1_file.c
index a3c32d91d1..0486696b0b 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1911,9 +1911,7 @@ int for_each_file_in_obj_subdir(unsigned int subdir_nr,
strbuf_setlen(path, baselen);
strbuf_addf(path, "/%s", de->d_name);
- if (strlen(de->d_name) == GIT_SHA1_HEXSZ - 2 &&
- !hex_to_bytes(oid.hash + 1, de->d_name,
- GIT_SHA1_RAWSZ - 1)) {
+ if (!get_oid_hex_tail(de->d_name, &oid, 1)) {
if (obj_cb) {
r = obj_cb(&oid, path->buf, data);
if (r)
--
2.15.0
