Jeff King <peff@xxxxxxxx> writes:
> On Tue, Nov 12, 2019 at 08:49:44PM +0900, Junio C Hamano wrote:
>
>> Jeff King <peff@xxxxxxxx> writes:
>>
>> >> @@ cache.h: int hex_to_bytes(unsigned char *binary, const char *hex, size_t len);
>> >> * buffers, making it safe to make multiple calls for a single statement, like:
>> >> *
>> >> - * printf("%s -> %s", sha1_to_hex(one), sha1_to_hex(two));
>> >> -+ * printf("%s -> %s", oid_to_hex(one), oid_to_hex(two));
>> >> ++ * printf("%s -> %s", hash_to_hex(one), hash_to_hex(two));
>> >> */
>> >> char *hash_to_hex_algop_r(char *buffer, const unsigned char *hash, const struct git_hash_algo *);
>> >> char *oid_to_hex_r(char *out, const struct object_id *oid);
>> >
>> > This one-liner leaves the types of "one" and "two" unspecified. :) So
>> > it's not wrong to use hash_to_hex(), but maybe it's better to be pushing
>> > people towards oid_to_hex() as their first choice? It probably doesn't
>> > matter too much either way.
>>
>> The pre-context of that comment reads:
>>
>> * Convert a binary hash to its hex equivalent. The `_r` variant is reentrant,
>> * and writes the NUL-terminated output to the buffer `out`, which must be at
>> * least `GIT_MAX_HEXSZ + 1` bytes, and returns a pointer to out for
>> * convenience.
>>
>> so I think the intent of the example that used to use sha1_to_hex()
>> has been the raw bytestring that is the object name, not its form
>> that is encapsulated in the "struct object_id()".
>
> I guess you're keying on the phrase "binary hash" there (the
> "GIT_MAX_HEXZ" bits only apply to the "_r" variants anyway). I'd read it
> as encompassing all of the functions below, including oid_to_hex(). But
> I'm OK with it either way.
Yes. "binary hash" is about "unsigned char[]". I think that's
historical accident---we added "struct object_id *" variants without
updating the comment.
Here is another try. The "everybody uses oid_to_hex" in the log
message has also been updated.
1: 8a030f1796 ! 1: b19f3fe9dd hex: drop sha1_to_hex()
@@ Metadata
## Commit message ##
hex: drop sha1_to_hex()
- There's only a single caller left of sha1_to_hex(), since everybody now
- uses oid_to_hex() instead. This case is in the sha1dc wrapper, where we
- print a hex sha1 when we find a collision. This one will always be sha1,
- regardless of the current hash algorithm, so we can't use oid_to_hex()
- here. In practice we'd probably not be running sha1 at all if it isn't
- the current algorithm, but it's possible we might still occasionally
+ There's only a single caller left of sha1_to_hex(), since everybody
+ that has an object name in "unsigned char[]" now uses hash_to_hex()
+ instead.
+
+ This case is in the sha1dc wrapper, where we print a hex sha1 when
+ we find a collision. This one will always be sha1, regardless of the
+ current hash algorithm, so we can't use hash_to_hex() here. In
+ practice we'd probably not be running sha1 at all if it isn't the
+ current algorithm, but it's possible we might still occasionally
need to compute a sha1 in a post-sha256 world.
Since sha1_to_hex() is just a wrapper for hash_to_hex_algop(), let's
@@ Commit message
it (and as with sha1_to_hex_r() in the previous patch, we'll drop the
coccinelle transformations, too).
- The sha1_to_hex() function is mentioned in a comment; we can easily swap
- that out for oid_to_hex() to give a better example. It's also mentioned
- in some test vectors in t4100, but that's not runnable code, so there's
- no point in trying to clean it up.
+ The sha1_to_hex() function is mentioned in a comment; we can easily
+ swap that out for oid_to_hex() to give a better example. Also
+ update the comment that was left stale when we added "struct
+ object_id *" as a way to name an object and added functions to
+ convert it to hex.
+
+ The function is also mentioned in some test vectors in t4100, but
+ that's not runnable code, so there's no point in trying to clean it
+ up.
Signed-off-by: Jeff King <peff@xxxxxxxx>
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
## cache.h ##
+@@ cache.h: int get_oid_hex(const char *hex, struct object_id *sha1);
+ int hex_to_bytes(unsigned char *binary, const char *hex, size_t len);
+
+ /*
+- * Convert a binary hash to its hex equivalent. The `_r` variant is reentrant,
++ * Convert a binary hash in "unsigned char []" or an object name in
++ * "struct object_id *" to its hex equivalent. The `_r` variant is reentrant,
+ * and writes the NUL-terminated output to the buffer `out`, which must be at
+ * least `GIT_MAX_HEXSZ + 1` bytes, and returns a pointer to out for
+ * convenience.
@@ cache.h: int hex_to_bytes(unsigned char *binary, const char *hex, size_t len);
* The non-`_r` variant returns a static buffer, but uses a ring of 4
* buffers, making it safe to make multiple calls for a single statement, like:
*
- * printf("%s -> %s", sha1_to_hex(one), sha1_to_hex(two));
++ * printf("%s -> %s", hash_to_hex(one), hash_to_hex(two));
+ * printf("%s -> %s", oid_to_hex(one), oid_to_hex(two));
*/
char *hash_to_hex_algop_r(char *buffer, const unsigned char *hash, const struct git_hash_algo *);
