refs/files-backend: convert many internals to struct object_id

Convert many of the internals of the files backend to use struct
object_id.  Avoid converting public APIs (except one change to
refs/ref-cache.c) to limit the scope of the changes.

Convert one use of get_sha1_hex to parse_oid_hex, and rely on the fact
that a strbuf will be NUL-terminated and that parse_oid_hex will fail on
truncated input to avoid the need to check the length.

This is a requirement to convert parse_object later on.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

3 files changed, 60 insertions, 72 deletions

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 413505ff07..2c360a4107 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -195,27 +195,15 @@ static const char PACKED_REFS_HEADER[] =
  * Return a pointer to the refname within the line (null-terminated),
  * or NULL if there was a problem.
  */
-static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
+static const char *parse_ref_line(struct strbuf *line, struct object_id *oid)
 {
 	const char *ref;
 
-	/*
-	 * 42: the answer to everything.
-	 *
-	 * In this case, it happens to be the answer to
-	 *  40 (length of sha1 hex representation)
-	 *  +1 (space in between hex and name)
-	 *  +1 (newline at the end of the line)
-	 */
-	if (line->len <= 42)
-		return NULL;
-
-	if (get_sha1_hex(line->buf, sha1) < 0)
+	if (parse_oid_hex(line->buf, oid, &ref) < 0)
 		return NULL;
-	if (!isspace(line->buf[40]))
+	if (!isspace(*ref++))
 		return NULL;
 
-	ref = line->buf + 41;
 	if (isspace(*ref))
 		return NULL;
 
@@ -260,7 +248,7 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 	enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
 
 	while (strbuf_getwholeline(&line, f, '\n') != EOF) {
-		unsigned char sha1[20];
+		struct object_id oid;
 		const char *refname;
 		const char *traits;
 
@@ -273,17 +261,17 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 			continue;
 		}
 
-		refname = parse_ref_line(&line, sha1);
+		refname = parse_ref_line(&line, &oid);
 		if (refname) {
 			int flag = REF_ISPACKED;
 
 			if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
 				if (!refname_is_safe(refname))
 					die("packed refname is dangerous: %s", refname);
-				hashclr(sha1);
+				oidclr(&oid);
 				flag |= REF_BAD_NAME | REF_ISBROKEN;
 			}
-			last = create_ref_entry(refname, sha1, flag, 0);
+			last = create_ref_entry(refname, &oid, flag, 0);
 			if (peeled == PEELED_FULLY ||
 			    (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
 				last->flag |= REF_KNOWS_PEELED;
@@ -294,8 +282,8 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 		    line.buf[0] == '^' &&
 		    line.len == PEELED_LINE_LENGTH &&
 		    line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
-		    !get_sha1_hex(line.buf + 1, sha1)) {
-			hashcpy(last->u.value.peeled.hash, sha1);
+		    !get_oid_hex(line.buf + 1, &oid)) {
+			oidcpy(&last->u.value.peeled, &oid);
 			/*
 			 * Regardless of what the file header said,
 			 * we definitely know the value of *this*
@@ -404,14 +392,14 @@ static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
  * commit_packed_refs().
  */
 static void add_packed_ref(struct files_ref_store *refs,
-			   const char *refname, const unsigned char *sha1)
+			   const char *refname, const struct object_id *oid)
 {
 	struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
 
 	if (!packed_ref_cache->lock)
 		die("internal error: packed refs not locked");
 	add_ref_entry(get_packed_ref_dir(packed_ref_cache),
-		      create_ref_entry(refname, sha1, REF_ISPACKED, 1));
+		      create_ref_entry(refname, oid, REF_ISPACKED, 1));
 }
 
 /*
@@ -444,7 +432,7 @@ static void loose_fill_ref_dir(struct ref_store *ref_store,
 	strbuf_add(&refname, dirname, dirnamelen);
 
 	while ((de = readdir(d)) != NULL) {
-		unsigned char sha1[20];
+		struct object_id oid;
 		struct stat st;
 		int flag;
 
@@ -465,10 +453,10 @@ static void loose_fill_ref_dir(struct ref_store *ref_store,
 			if (!refs_resolve_ref_unsafe(&refs->base,
 						     refname.buf,
 						     RESOLVE_REF_READING,
-						     sha1, &flag)) {
-				hashclr(sha1);
+						     oid.hash, &flag)) {
+				oidclr(&oid);
 				flag |= REF_ISBROKEN;
-			} else if (is_null_sha1(sha1)) {
+			} else if (is_null_oid(&oid)) {
 				/*
 				 * It is so astronomically unlikely
 				 * that NULL_SHA1 is the SHA-1 of an
@@ -484,11 +472,11 @@ static void loose_fill_ref_dir(struct ref_store *ref_store,
 						 REFNAME_ALLOW_ONELEVEL)) {
 				if (!refname_is_safe(refname.buf))
 					die("loose refname is dangerous: %s", refname.buf);
-				hashclr(sha1);
+				oidclr(&oid);
 				flag |= REF_BAD_NAME | REF_ISBROKEN;
 			}
 			add_entry_to_dir(dir,
-					 create_ref_entry(refname.buf, sha1, flag, 0));
+					 create_ref_entry(refname.buf, &oid, flag, 0));
 		}
 		strbuf_setlen(&refname, dirnamelen);
 		strbuf_setlen(&path, path_baselen);
@@ -1526,7 +1514,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 			packed_entry->flag = REF_ISPACKED;
 			oidcpy(&packed_entry->u.value.oid, iter->oid);
 		} else {
-			packed_entry = create_ref_entry(iter->refname, iter->oid->hash,
+			packed_entry = create_ref_entry(iter->refname, iter->oid,
 							REF_ISPACKED, 0);
 			add_ref_entry(packed_refs, packed_entry);
 		}
@@ -1709,10 +1697,10 @@ static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
 }
 
 static int write_ref_to_lockfile(struct ref_lock *lock,
-				 const unsigned char *sha1, struct strbuf *err);
+				 const struct object_id *oid, struct strbuf *err);
 static int commit_ref_update(struct files_ref_store *refs,
 			     struct ref_lock *lock,
-			     const unsigned char *sha1, const char *logmsg,
+			     const struct object_id *oid, const char *logmsg,
 			     struct strbuf *err);
 
 static int files_rename_ref(struct ref_store *ref_store,
@@ -1721,7 +1709,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 {
 	struct files_ref_store *refs =
 		files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
-	unsigned char sha1[20], orig_sha1[20];
+	struct object_id oid, orig_oid;
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
 	struct stat loginfo;
@@ -1743,7 +1731,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 
 	if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
 				     RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-				orig_sha1, &flag)) {
+				orig_oid.hash, &flag)) {
 		ret = error("refname %s not found", oldrefname);
 		goto out;
 	}
@@ -1765,21 +1753,21 @@ static int files_rename_ref(struct ref_store *ref_store,
 	}
 
 	if (refs_delete_ref(&refs->base, logmsg, oldrefname,
-			    orig_sha1, REF_NODEREF)) {
+			    orig_oid.hash, REF_NODEREF)) {
 		error("unable to delete old %s", oldrefname);
 		goto rollback;
 	}
 
 	/*
-	 * Since we are doing a shallow lookup, sha1 is not the
-	 * correct value to pass to delete_ref as old_sha1. But that
-	 * doesn't matter, because an old_sha1 check wouldn't add to
+	 * Since we are doing a shallow lookup, oid is not the
+	 * correct value to pass to delete_ref as old_oid. But that
+	 * doesn't matter, because an old_oid check wouldn't add to
 	 * the safety anyway; we want to delete the reference whatever
 	 * its current value.
 	 */
 	if (!refs_read_ref_full(&refs->base, newrefname,
 				RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-				sha1, NULL) &&
+				oid.hash, NULL) &&
 	    refs_delete_ref(&refs->base, NULL, newrefname,
 			    NULL, REF_NODEREF)) {
 		if (errno == EISDIR) {
@@ -1812,10 +1800,10 @@ static int files_rename_ref(struct ref_store *ref_store,
 		strbuf_release(&err);
 		goto rollback;
 	}
-	hashcpy(lock->old_oid.hash, orig_sha1);
+	oidcpy(&lock->old_oid, &orig_oid);
 
-	if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
-	    commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) {
+	if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
+	    commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) {
 		error("unable to write current sha1 into %s: %s", newrefname, err.buf);
 		strbuf_release(&err);
 		goto rollback;
@@ -1835,8 +1823,8 @@ static int files_rename_ref(struct ref_store *ref_store,
 
 	flag = log_all_ref_updates;
 	log_all_ref_updates = LOG_REFS_NONE;
-	if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
-	    commit_ref_update(refs, lock, orig_sha1, NULL, &err)) {
+	if (write_ref_to_lockfile(lock, &orig_oid, &err) ||
+	    commit_ref_update(refs, lock, &orig_oid, NULL, &err)) {
 		error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
 		strbuf_release(&err);
 	}
@@ -1986,8 +1974,8 @@ static int files_create_reflog(struct ref_store *ref_store,
 	return 0;
 }
 
-static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
-			    const unsigned char *new_sha1,
+static int log_ref_write_fd(int fd, const struct object_id *old_oid,
+			    const struct object_id *new_oid,
 			    const char *committer, const char *msg)
 {
 	int msglen, written;
@@ -1998,8 +1986,8 @@ static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
 	maxlen = strlen(committer) + msglen + 100;
 	logrec = xmalloc(maxlen);
 	len = xsnprintf(logrec, maxlen, "%s %s %s\n",
-			sha1_to_hex(old_sha1),
-			sha1_to_hex(new_sha1),
+			oid_to_hex(old_oid),
+			oid_to_hex(new_oid),
 			committer);
 	if (msglen)
 		len += copy_reflog_msg(logrec + len - 1, msg) - 1;
@@ -2013,8 +2001,8 @@ static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
 }
 
 static int files_log_ref_write(struct files_ref_store *refs,
-			       const char *refname, const unsigned char *old_sha1,
-			       const unsigned char *new_sha1, const char *msg,
+			       const char *refname, const struct object_id *old_oid,
+			       const struct object_id *new_oid, const char *msg,
 			       int flags, struct strbuf *err)
 {
 	int logfd, result;
@@ -2031,7 +2019,7 @@ static int files_log_ref_write(struct files_ref_store *refs,
 
 	if (logfd < 0)
 		return 0;
-	result = log_ref_write_fd(logfd, old_sha1, new_sha1,
+	result = log_ref_write_fd(logfd, old_oid, new_oid,
 				  git_committer_info(0), msg);
 	if (result) {
 		struct strbuf sb = STRBUF_INIT;
@@ -2063,29 +2051,29 @@ static int files_log_ref_write(struct files_ref_store *refs,
  * return -1.
  */
 static int write_ref_to_lockfile(struct ref_lock *lock,
-				 const unsigned char *sha1, struct strbuf *err)
+				 const struct object_id *oid, struct strbuf *err)
 {
 	static char term = '\n';
 	struct object *o;
 	int fd;
 
-	o = parse_object(sha1);
+	o = parse_object(oid->hash);
 	if (!o) {
 		strbuf_addf(err,
 			    "trying to write ref '%s' with nonexistent object %s",
-			    lock->ref_name, sha1_to_hex(sha1));
+			    lock->ref_name, oid_to_hex(oid));
 		unlock_ref(lock);
 		return -1;
 	}
 	if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
 		strbuf_addf(err,
 			    "trying to write non-commit object %s to branch '%s'",
-			    sha1_to_hex(sha1), lock->ref_name);
+			    oid_to_hex(oid), lock->ref_name);
 		unlock_ref(lock);
 		return -1;
 	}
 	fd = get_lock_file_fd(lock->lk);
-	if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
+	if (write_in_full(fd, oid_to_hex(oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||
 	    write_in_full(fd, &term, 1) != 1 ||
 	    close_ref(lock) < 0) {
 		strbuf_addf(err,
@@ -2103,14 +2091,14 @@ static int write_ref_to_lockfile(struct ref_lock *lock,
  */
 static int commit_ref_update(struct files_ref_store *refs,
 			     struct ref_lock *lock,
-			     const unsigned char *sha1, const char *logmsg,
+			     const struct object_id *oid, const char *logmsg,
 			     struct strbuf *err)
 {
 	files_assert_main_repository(refs, "commit_ref_update");
 
 	clear_loose_ref_cache(refs);
 	if (files_log_ref_write(refs, lock->ref_name,
-				lock->old_oid.hash, sha1,
+				&lock->old_oid, oid,
 				logmsg, 0, err)) {
 		char *old_msg = strbuf_detach(err, NULL);
 		strbuf_addf(err, "cannot update the ref '%s': %s",
@@ -2133,18 +2121,18 @@ static int commit_ref_update(struct files_ref_store *refs,
 		 * check with HEAD only which should cover 99% of all usage
 		 * scenarios (even 100% of the default ones).
 		 */
-		unsigned char head_sha1[20];
+		struct object_id head_oid;
 		int head_flag;
 		const char *head_ref;
 
 		head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
 						   RESOLVE_REF_READING,
-						   head_sha1, &head_flag);
+						   head_oid.hash, &head_flag);
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name)) {
 			struct strbuf log_err = STRBUF_INIT;
 			if (files_log_ref_write(refs, "HEAD",
-						lock->old_oid.hash, sha1,
+						&lock->old_oid, oid,
 						logmsg, 0, &log_err)) {
 				error("%s", log_err.buf);
 				strbuf_release(&log_err);
@@ -2182,12 +2170,12 @@ static void update_symref_reflog(struct files_ref_store *refs,
 				 const char *target, const char *logmsg)
 {
 	struct strbuf err = STRBUF_INIT;
-	unsigned char new_sha1[20];
+	struct object_id new_oid;
 	if (logmsg &&
 	    !refs_read_ref_full(&refs->base, target,
-				RESOLVE_REF_READING, new_sha1, NULL) &&
-	    files_log_ref_write(refs, refname, lock->old_oid.hash,
-				new_sha1, logmsg, 0, &err)) {
+				RESOLVE_REF_READING, new_oid.hash, NULL) &&
+	    files_log_ref_write(refs, refname, &lock->old_oid,
+				&new_oid, logmsg, 0, &err)) {
 		error("%s", err.buf);
 		strbuf_release(&err);
 	}
@@ -2866,7 +2854,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 			 * The reference already has the desired
 			 * value, so we don't need to write it.
 			 */
-		} else if (write_ref_to_lockfile(lock, update->new_oid.hash,
+		} else if (write_ref_to_lockfile(lock, &update->new_oid,
 						 err)) {
 			char *write_err = strbuf_detach(err, NULL);
 
@@ -3001,8 +2989,8 @@ static int files_transaction_commit(struct ref_store *ref_store,
 		    update->flags & REF_LOG_ONLY) {
 			if (files_log_ref_write(refs,
 						lock->ref_name,
-						lock->old_oid.hash,
-						update->new_oid.hash,
+						&lock->old_oid,
+						&update->new_oid,
 						update->msg, update->flags,
 						err)) {
 				char *old_msg = strbuf_detach(err, NULL);
@@ -3174,7 +3162,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 		if ((update->flags & REF_HAVE_NEW) &&
 		    !is_null_oid(&update->new_oid))
 			add_packed_ref(refs, update->refname,
-				       update->new_oid.hash);
+				       &update->new_oid);
 	}
 
 	if (commit_packed_refs(refs)) {
diff --git a/refs/ref-cache.c b/refs/ref-cache.c
index 6059362f1d..6b11d9cd12 100644
--- a/refs/ref-cache.c
+++ b/refs/ref-cache.c
@@ -32,7 +32,7 @@ struct ref_dir *get_ref_dir(struct ref_entry *entry)
 }
 
 struct ref_entry *create_ref_entry(const char *refname,
-				   const unsigned char *sha1, int flag,
+				   const struct object_id *oid, int flag,
 				   int check_name)
 {
 	struct ref_entry *ref;
@@ -41,7 +41,7 @@ struct ref_entry *create_ref_entry(const char *refname,
 	    check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
 		die("Reference has invalid format: '%s'", refname);
 	FLEX_ALLOC_STR(ref, name, refname);
-	hashcpy(ref->u.value.oid.hash, sha1);
+	oidcpy(&ref->u.value.oid, oid);
 	oidclr(&ref->u.value.peeled);
 	ref->flag = flag;
 	return ref;
diff --git a/refs/ref-cache.h b/refs/ref-cache.h
index ffdc54f3f0..1f65e2f9ed 100644
--- a/refs/ref-cache.h
+++ b/refs/ref-cache.h
@@ -185,7 +185,7 @@ struct ref_entry *create_dir_entry(struct ref_cache *cache,
 				   int incomplete);
 
 struct ref_entry *create_ref_entry(const char *refname,
-				   const unsigned char *sha1, int flag,
+				   const struct object_id *oid, int flag,
 				   int check_name);
 
 /*