diff: use skip_to_optional_arg_default() in parsing --relative
[gitweb.git] / refs.c
diff --git a/refs.c b/refs.c
index 41aec6505d1309fa2efed2bd9aca0a0ef2646444..339d4318ee4500ffeb26426bdf9976979ecf739a 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -174,23 +174,41 @@ int refname_is_safe(const char *refname)
        return 1;
 }
 
+/*
+ * Return true if refname, which has the specified oid and flags, can
+ * be resolved to an object in the database. If the referred-to object
+ * does not exist, emit a warning and return false.
+ */
+int ref_resolves_to_object(const char *refname,
+                          const struct object_id *oid,
+                          unsigned int flags)
+{
+       if (flags & REF_ISBROKEN)
+               return 0;
+       if (!has_sha1_file(oid->hash)) {
+               error("%s does not point to a valid object!", refname);
+               return 0;
+       }
+       return 1;
+}
+
 char *refs_resolve_refdup(struct ref_store *refs,
                          const char *refname, int resolve_flags,
-                         unsigned char *sha1, int *flags)
+                         struct object_id *oid, int *flags)
 {
        const char *result;
 
        result = refs_resolve_ref_unsafe(refs, refname, resolve_flags,
-                                        sha1, flags);
+                                        oid, flags);
        return xstrdup_or_null(result);
 }
 
 char *resolve_refdup(const char *refname, int resolve_flags,
-                    unsigned char *sha1, int *flags)
+                    struct object_id *oid, int *flags)
 {
        return refs_resolve_refdup(get_main_ref_store(),
                                   refname, resolve_flags,
-                                  sha1, flags);
+                                  oid, flags);
 }
 
 /* The argument to filter_refs */
@@ -201,28 +219,27 @@ struct ref_filter {
 };
 
 int refs_read_ref_full(struct ref_store *refs, const char *refname,
-                      int resolve_flags, unsigned char *sha1, int *flags)
+                      int resolve_flags, struct object_id *oid, int *flags)
 {
-       if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, sha1, flags))
+       if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, oid, flags))
                return 0;
        return -1;
 }
 
-int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
+int read_ref_full(const char *refname, int resolve_flags, struct object_id *oid, int *flags)
 {
        return refs_read_ref_full(get_main_ref_store(), refname,
-                                 resolve_flags, sha1, flags);
+                                 resolve_flags, oid, flags);
 }
 
-int read_ref(const char *refname, unsigned char *sha1)
+int read_ref(const char *refname, struct object_id *oid)
 {
-       return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
+       return read_ref_full(refname, RESOLVE_REF_READING, oid, NULL);
 }
 
 int ref_exists(const char *refname)
 {
-       unsigned char sha1[20];
-       return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
+       return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, NULL, NULL);
 }
 
 static int filter_refs(const char *refname, const struct object_id *oid,
@@ -235,12 +252,12 @@ static int filter_refs(const char *refname, const struct object_id *oid,
        return filter->fn(refname, oid, flags, filter->cb_data);
 }
 
-enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
+enum peel_status peel_object(const struct object_id *name, struct object_id *oid)
 {
-       struct object *o = lookup_unknown_object(name);
+       struct object *o = lookup_unknown_object(name->hash);
 
        if (o->type == OBJ_NONE) {
-               int type = sha1_object_info(name, NULL);
+               int type = sha1_object_info(name->hash, NULL);
                if (type < 0 || !object_as_type(o, type, 0))
                        return PEEL_INVALID;
        }
@@ -252,7 +269,7 @@ enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
        if (!o)
                return PEEL_INVALID;
 
-       hashcpy(sha1, o->oid.hash);
+       oidcpy(oid, &o->oid);
        return PEEL_PEELED;
 }
 
@@ -268,12 +285,11 @@ static int warn_if_dangling_symref(const char *refname, const struct object_id *
 {
        struct warn_if_dangling_data *d = cb_data;
        const char *resolves_to;
-       struct object_id junk;
 
        if (!(flags & REF_ISSYMREF))
                return 0;
 
-       resolves_to = resolve_ref_unsafe(refname, 0, junk.hash, NULL);
+       resolves_to = resolve_ref_unsafe(refname, 0, NULL, NULL);
        if (!resolves_to
            || (d->refname
                ? strcmp(resolves_to, d->refname)
@@ -318,12 +334,6 @@ int for_each_tag_ref(each_ref_fn fn, void *cb_data)
        return refs_for_each_tag_ref(get_main_ref_store(), fn, cb_data);
 }
 
-int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
-{
-       return refs_for_each_tag_ref(get_submodule_ref_store(submodule),
-                                    fn, cb_data);
-}
-
 int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 {
        return refs_for_each_ref_in(refs, "refs/heads/", fn, cb_data);
@@ -334,12 +344,6 @@ int for_each_branch_ref(each_ref_fn fn, void *cb_data)
        return refs_for_each_branch_ref(get_main_ref_store(), fn, cb_data);
 }
 
-int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
-{
-       return refs_for_each_branch_ref(get_submodule_ref_store(submodule),
-                                       fn, cb_data);
-}
-
 int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 {
        return refs_for_each_ref_in(refs, "refs/remotes/", fn, cb_data);
@@ -350,12 +354,6 @@ int for_each_remote_ref(each_ref_fn fn, void *cb_data)
        return refs_for_each_remote_ref(get_main_ref_store(), fn, cb_data);
 }
 
-int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
-{
-       return refs_for_each_remote_ref(get_submodule_ref_store(submodule),
-                                       fn, cb_data);
-}
-
 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 {
        struct strbuf buf = STRBUF_INIT;
@@ -364,7 +362,7 @@ int head_ref_namespaced(each_ref_fn fn, void *cb_data)
        int flag;
 
        strbuf_addf(&buf, "%sHEAD", get_git_namespace());
-       if (!read_ref_full(buf.buf, RESOLVE_REF_READING, oid.hash, &flag))
+       if (!read_ref_full(buf.buf, RESOLVE_REF_READING, &oid, &flag))
                ret = fn(buf.buf, &oid, flag, cb_data);
        strbuf_release(&buf);
 
@@ -458,15 +456,15 @@ static char *substitute_branch_name(const char **string, int *len)
        return NULL;
 }
 
-int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
+int dwim_ref(const char *str, int len, struct object_id *oid, char **ref)
 {
        char *last_branch = substitute_branch_name(&str, &len);
-       int   refs_found  = expand_ref(str, len, sha1, ref);
+       int   refs_found  = expand_ref(str, len, oid, ref);
        free(last_branch);
        return refs_found;
 }
 
-int expand_ref(const char *str, int len, unsigned char *sha1, char **ref)
+int expand_ref(const char *str, int len, struct object_id *oid, char **ref)
 {
        const char **p, *r;
        int refs_found = 0;
@@ -474,11 +472,11 @@ int expand_ref(const char *str, int len, unsigned char *sha1, char **ref)
 
        *ref = NULL;
        for (p = ref_rev_parse_rules; *p; p++) {
-               unsigned char sha1_from_ref[20];
-               unsigned char *this_result;
+               struct object_id oid_from_ref;
+               struct object_id *this_result;
                int flag;
 
-               this_result = refs_found ? sha1_from_ref : sha1;
+               this_result = refs_found ? &oid_from_ref : oid;
                strbuf_reset(&fullref);
                strbuf_addf(&fullref, *p, len, str);
                r = resolve_ref_unsafe(fullref.buf, RESOLVE_REF_READING,
@@ -498,7 +496,7 @@ int expand_ref(const char *str, int len, unsigned char *sha1, char **ref)
        return refs_found;
 }
 
-int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
+int dwim_log(const char *str, int len, struct object_id *oid, char **log)
 {
        char *last_branch = substitute_branch_name(&str, &len);
        const char **p;
@@ -507,13 +505,13 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 
        *log = NULL;
        for (p = ref_rev_parse_rules; *p; p++) {
-               unsigned char hash[20];
+               struct object_id hash;
                const char *ref, *it;
 
                strbuf_reset(&path);
                strbuf_addf(&path, *p, len, str);
                ref = resolve_ref_unsafe(path.buf, RESOLVE_REF_READING,
-                                        hash, NULL);
+                                        &hash, NULL);
                if (!ref)
                        continue;
                if (reflog_exists(path.buf))
@@ -524,7 +522,7 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
                        continue;
                if (!logs_found++) {
                        *log = xstrdup(it);
-                       hashcpy(sha1, hash);
+                       oidcpy(oid, &hash);
                }
                if (!warn_ambiguous_refs)
                        break;
@@ -561,8 +559,23 @@ enum ref_type ref_type(const char *refname)
        return REF_TYPE_NORMAL;
 }
 
-static int write_pseudoref(const char *pseudoref, const unsigned char *sha1,
-                          const unsigned char *old_sha1, struct strbuf *err)
+long get_files_ref_lock_timeout_ms(void)
+{
+       static int configured = 0;
+
+       /* The default timeout is 100 ms: */
+       static int timeout_ms = 100;
+
+       if (!configured) {
+               git_config_get_int("core.filesreflocktimeout", &timeout_ms);
+               configured = 1;
+       }
+
+       return timeout_ms;
+}
+
+static int write_pseudoref(const char *pseudoref, const struct object_id *oid,
+                          const struct object_id *old_oid, struct strbuf *err)
 {
        const char *filename;
        int fd;
@@ -570,29 +583,34 @@ static int write_pseudoref(const char *pseudoref, const unsigned char *sha1,
        struct strbuf buf = STRBUF_INIT;
        int ret = -1;
 
-       strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
+       if (!oid)
+               return 0;
+
+       strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
 
        filename = git_path("%s", pseudoref);
-       fd = hold_lock_file_for_update(&lock, filename, LOCK_DIE_ON_ERROR);
+       fd = hold_lock_file_for_update_timeout(&lock, filename,
+                                              LOCK_DIE_ON_ERROR,
+                                              get_files_ref_lock_timeout_ms());
        if (fd < 0) {
                strbuf_addf(err, "could not open '%s' for writing: %s",
                            filename, strerror(errno));
-               return -1;
+               goto done;
        }
 
-       if (old_sha1) {
-               unsigned char actual_old_sha1[20];
+       if (old_oid) {
+               struct object_id actual_old_oid;
 
-               if (read_ref(pseudoref, actual_old_sha1))
+               if (read_ref(pseudoref, &actual_old_oid))
                        die("could not read ref '%s'", pseudoref);
-               if (hashcmp(actual_old_sha1, old_sha1)) {
+               if (oidcmp(&actual_old_oid, old_oid)) {
                        strbuf_addf(err, "unexpected sha1 when writing '%s'", pseudoref);
                        rollback_lock_file(&lock);
                        goto done;
                }
        }
 
-       if (write_in_full(fd, buf.buf, buf.len) != buf.len) {
+       if (write_in_full(fd, buf.buf, buf.len) < 0) {
                strbuf_addf(err, "could not write to '%s'", filename);
                rollback_lock_file(&lock);
                goto done;
@@ -605,24 +623,25 @@ static int write_pseudoref(const char *pseudoref, const unsigned char *sha1,
        return ret;
 }
 
-static int delete_pseudoref(const char *pseudoref, const unsigned char *old_sha1)
+static int delete_pseudoref(const char *pseudoref, const struct object_id *old_oid)
 {
        static struct lock_file lock;
        const char *filename;
 
        filename = git_path("%s", pseudoref);
 
-       if (old_sha1 && !is_null_sha1(old_sha1)) {
+       if (old_oid && !is_null_oid(old_oid)) {
                int fd;
-               unsigned char actual_old_sha1[20];
+               struct object_id actual_old_oid;
 
-               fd = hold_lock_file_for_update(&lock, filename,
-                                              LOCK_DIE_ON_ERROR);
+               fd = hold_lock_file_for_update_timeout(
+                               &lock, filename, LOCK_DIE_ON_ERROR,
+                               get_files_ref_lock_timeout_ms());
                if (fd < 0)
                        die_errno(_("Could not open '%s' for writing"), filename);
-               if (read_ref(pseudoref, actual_old_sha1))
+               if (read_ref(pseudoref, &actual_old_oid))
                        die("could not read ref '%s'", pseudoref);
-               if (hashcmp(actual_old_sha1, old_sha1)) {
+               if (oidcmp(&actual_old_oid, old_oid)) {
                        warning("Unexpected sha1 when deleting %s", pseudoref);
                        rollback_lock_file(&lock);
                        return -1;
@@ -639,7 +658,7 @@ static int delete_pseudoref(const char *pseudoref, const unsigned char *old_sha1
 
 int refs_delete_ref(struct ref_store *refs, const char *msg,
                    const char *refname,
-                   const unsigned char *old_sha1,
+                   const struct object_id *old_oid,
                    unsigned int flags)
 {
        struct ref_transaction *transaction;
@@ -647,12 +666,12 @@ int refs_delete_ref(struct ref_store *refs, const char *msg,
 
        if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
                assert(refs == get_main_ref_store());
-               return delete_pseudoref(refname, old_sha1);
+               return delete_pseudoref(refname, old_oid);
        }
 
        transaction = ref_store_transaction_begin(refs, &err);
        if (!transaction ||
-           ref_transaction_delete(transaction, refname, old_sha1,
+           ref_transaction_delete(transaction, refname, old_oid,
                                   flags, msg, &err) ||
            ref_transaction_commit(transaction, &err)) {
                error("%s", err.buf);
@@ -666,10 +685,10 @@ int refs_delete_ref(struct ref_store *refs, const char *msg,
 }
 
 int delete_ref(const char *msg, const char *refname,
-              const unsigned char *old_sha1, unsigned int flags)
+              const struct object_id *old_oid, unsigned int flags)
 {
        return refs_delete_ref(get_main_ref_store(), msg, refname,
-                              old_sha1, flags);
+                              old_oid, flags);
 }
 
 int copy_reflog_msg(char *buf, const char *msg)
@@ -718,11 +737,11 @@ struct read_ref_at_cb {
        timestamp_t at_time;
        int cnt;
        int reccnt;
-       unsigned char *sha1;
+       struct object_id *oid;
        int found_it;
 
-       unsigned char osha1[20];
-       unsigned char nsha1[20];
+       struct object_id ooid;
+       struct object_id noid;
        int tz;
        timestamp_t date;
        char **msg;
@@ -751,28 +770,28 @@ static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
                if (cb->cutoff_cnt)
                        *cb->cutoff_cnt = cb->reccnt - 1;
                /*
-                * we have not yet updated cb->[n|o]sha1 so they still
+                * we have not yet updated cb->[n|o]oid so they still
                 * hold the values for the previous record.
                 */
-               if (!is_null_sha1(cb->osha1)) {
-                       hashcpy(cb->sha1, noid->hash);
-                       if (hashcmp(cb->osha1, noid->hash))
+               if (!is_null_oid(&cb->ooid)) {
+                       oidcpy(cb->oid, noid);
+                       if (oidcmp(&cb->ooid, noid))
                                warning("Log for ref %s has gap after %s.",
                                        cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
                }
                else if (cb->date == cb->at_time)
-                       hashcpy(cb->sha1, noid->hash);
-               else if (hashcmp(noid->hash, cb->sha1))
+                       oidcpy(cb->oid, noid);
+               else if (oidcmp(noid, cb->oid))
                        warning("Log for ref %s unexpectedly ended on %s.",
                                cb->refname, show_date(cb->date, cb->tz,
                                                       DATE_MODE(RFC2822)));
-               hashcpy(cb->osha1, ooid->hash);
-               hashcpy(cb->nsha1, noid->hash);
+               oidcpy(&cb->ooid, ooid);
+               oidcpy(&cb->noid, noid);
                cb->found_it = 1;
                return 1;
        }
-       hashcpy(cb->osha1, ooid->hash);
-       hashcpy(cb->nsha1, noid->hash);
+       oidcpy(&cb->ooid, ooid);
+       oidcpy(&cb->noid, noid);
        if (cb->cnt > 0)
                cb->cnt--;
        return 0;
@@ -792,15 +811,15 @@ static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid
                *cb->cutoff_tz = tz;
        if (cb->cutoff_cnt)
                *cb->cutoff_cnt = cb->reccnt;
-       hashcpy(cb->sha1, ooid->hash);
-       if (is_null_sha1(cb->sha1))
-               hashcpy(cb->sha1, noid->hash);
+       oidcpy(cb->oid, ooid);
+       if (is_null_oid(cb->oid))
+               oidcpy(cb->oid, noid);
        /* We just want the first entry */
        return 1;
 }
 
 int read_ref_at(const char *refname, unsigned int flags, timestamp_t at_time, int cnt,
-               unsigned char *sha1, char **msg,
+               struct object_id *oid, char **msg,
                timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
 {
        struct read_ref_at_cb cb;
@@ -813,12 +832,12 @@ int read_ref_at(const char *refname, unsigned int flags, timestamp_t at_time, in
        cb.cutoff_time = cutoff_time;
        cb.cutoff_tz = cutoff_tz;
        cb.cutoff_cnt = cutoff_cnt;
-       cb.sha1 = sha1;
+       cb.oid = oid;
 
        for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
 
        if (!cb.reccnt) {
-               if (flags & GET_SHA1_QUIETLY)
+               if (flags & GET_OID_QUIETLY)
                        exit(128);
                else
                        die("Log for %s is empty.", refname);
@@ -878,8 +897,8 @@ void ref_transaction_free(struct ref_transaction *transaction)
 struct ref_update *ref_transaction_add_update(
                struct ref_transaction *transaction,
                const char *refname, unsigned int flags,
-               const unsigned char *new_sha1,
-               const unsigned char *old_sha1,
+               const struct object_id *new_oid,
+               const struct object_id *old_oid,
                const char *msg)
 {
        struct ref_update *update;
@@ -887,9 +906,6 @@ struct ref_update *ref_transaction_add_update(
        if (transaction->state != REF_TRANSACTION_OPEN)
                die("BUG: update called for transaction that is not open");
 
-       if ((flags & REF_ISPRUNING) && !(flags & REF_NODEREF))
-               die("BUG: REF_ISPRUNING set without REF_NODEREF");
-
        FLEX_ALLOC_STR(update, refname, refname);
        ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
        transaction->updates[transaction->nr++] = update;
@@ -897,23 +913,23 @@ struct ref_update *ref_transaction_add_update(
        update->flags = flags;
 
        if (flags & REF_HAVE_NEW)
-               hashcpy(update->new_oid.hash, new_sha1);
+               oidcpy(&update->new_oid, new_oid);
        if (flags & REF_HAVE_OLD)
-               hashcpy(update->old_oid.hash, old_sha1);
+               oidcpy(&update->old_oid, old_oid);
        update->msg = xstrdup_or_null(msg);
        return update;
 }
 
 int ref_transaction_update(struct ref_transaction *transaction,
                           const char *refname,
-                          const unsigned char *new_sha1,
-                          const unsigned char *old_sha1,
+                          const struct object_id *new_oid,
+                          const struct object_id *old_oid,
                           unsigned int flags, const char *msg,
                           struct strbuf *err)
 {
        assert(err);
 
-       if ((new_sha1 && !is_null_sha1(new_sha1)) ?
+       if ((new_oid && !is_null_oid(new_oid)) ?
            check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
            !refname_is_safe(refname)) {
                strbuf_addf(err, "refusing to update ref with bad name '%s'",
@@ -921,64 +937,57 @@ int ref_transaction_update(struct ref_transaction *transaction,
                return -1;
        }
 
-       flags &= REF_TRANSACTION_UPDATE_ALLOWED_FLAGS;
+       if (flags & ~REF_TRANSACTION_UPDATE_ALLOWED_FLAGS)
+               BUG("illegal flags 0x%x passed to ref_transaction_update()", flags);
 
-       flags |= (new_sha1 ? REF_HAVE_NEW : 0) | (old_sha1 ? REF_HAVE_OLD : 0);
+       flags |= (new_oid ? REF_HAVE_NEW : 0) | (old_oid ? REF_HAVE_OLD : 0);
 
        ref_transaction_add_update(transaction, refname, flags,
-                                  new_sha1, old_sha1, msg);
+                                  new_oid, old_oid, msg);
        return 0;
 }
 
 int ref_transaction_create(struct ref_transaction *transaction,
                           const char *refname,
-                          const unsigned char *new_sha1,
+                          const struct object_id *new_oid,
                           unsigned int flags, const char *msg,
                           struct strbuf *err)
 {
-       if (!new_sha1 || is_null_sha1(new_sha1))
-               die("BUG: create called without valid new_sha1");
-       return ref_transaction_update(transaction, refname, new_sha1,
-                                     null_sha1, flags, msg, err);
+       if (!new_oid || is_null_oid(new_oid))
+               die("BUG: create called without valid new_oid");
+       return ref_transaction_update(transaction, refname, new_oid,
+                                     &null_oid, flags, msg, err);
 }
 
 int ref_transaction_delete(struct ref_transaction *transaction,
                           const char *refname,
-                          const unsigned char *old_sha1,
+                          const struct object_id *old_oid,
                           unsigned int flags, const char *msg,
                           struct strbuf *err)
 {
-       if (old_sha1 && is_null_sha1(old_sha1))
-               die("BUG: delete called with old_sha1 set to zeros");
+       if (old_oid && is_null_oid(old_oid))
+               die("BUG: delete called with old_oid set to zeros");
        return ref_transaction_update(transaction, refname,
-                                     null_sha1, old_sha1,
+                                     &null_oid, old_oid,
                                      flags, msg, err);
 }
 
 int ref_transaction_verify(struct ref_transaction *transaction,
                           const char *refname,
-                          const unsigned char *old_sha1,
+                          const struct object_id *old_oid,
                           unsigned int flags,
                           struct strbuf *err)
 {
-       if (!old_sha1)
-               die("BUG: verify called with old_sha1 set to NULL");
+       if (!old_oid)
+               die("BUG: verify called with old_oid set to NULL");
        return ref_transaction_update(transaction, refname,
-                                     NULL, old_sha1,
+                                     NULL, old_oid,
                                      flags, NULL, err);
 }
 
-int update_ref_oid(const char *msg, const char *refname,
-              const struct object_id *new_oid, const struct object_id *old_oid,
-              unsigned int flags, enum action_on_err onerr)
-{
-       return update_ref(msg, refname, new_oid ? new_oid->hash : NULL,
-               old_oid ? old_oid->hash : NULL, flags, onerr);
-}
-
 int refs_update_ref(struct ref_store *refs, const char *msg,
-                   const char *refname, const unsigned char *new_sha1,
-                   const unsigned char *old_sha1, unsigned int flags,
+                   const char *refname, const struct object_id *new_oid,
+                   const struct object_id *old_oid, unsigned int flags,
                    enum action_on_err onerr)
 {
        struct ref_transaction *t = NULL;
@@ -987,11 +996,11 @@ int refs_update_ref(struct ref_store *refs, const char *msg,
 
        if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
                assert(refs == get_main_ref_store());
-               ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
+               ret = write_pseudoref(refname, new_oid, old_oid, &err);
        } else {
                t = ref_store_transaction_begin(refs, &err);
                if (!t ||
-                   ref_transaction_update(t, refname, new_sha1, old_sha1,
+                   ref_transaction_update(t, refname, new_oid, old_oid,
                                           flags, msg, &err) ||
                    ref_transaction_commit(t, &err)) {
                        ret = 1;
@@ -1021,12 +1030,12 @@ int refs_update_ref(struct ref_store *refs, const char *msg,
 }
 
 int update_ref(const char *msg, const char *refname,
-              const unsigned char *new_sha1,
-              const unsigned char *old_sha1,
+              const struct object_id *new_oid,
+              const struct object_id *old_oid,
               unsigned int flags, enum action_on_err onerr)
 {
-       return refs_update_ref(get_main_ref_store(), msg, refname, new_sha1,
-                              old_sha1, flags, onerr);
+       return refs_update_ref(get_main_ref_store(), msg, refname, new_oid,
+                              old_oid, flags, onerr);
 }
 
 char *shorten_unambiguous_ref(const char *refname, int strict)
@@ -1232,19 +1241,13 @@ int refs_rename_ref_available(struct ref_store *refs,
        return ok;
 }
 
-int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
+int refs_head_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 {
        struct object_id oid;
        int flag;
 
-       if (submodule) {
-               if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
-                       return fn("HEAD", &oid, 0, cb_data);
-
-               return 0;
-       }
-
-       if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
+       if (!refs_read_ref_full(refs, "HEAD", RESOLVE_REF_READING,
+                               &oid, &flag))
                return fn("HEAD", &oid, flag, cb_data);
 
        return 0;
@@ -1252,7 +1255,7 @@ int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 
 int head_ref(each_ref_fn fn, void *cb_data)
 {
-       return head_ref_submodule(NULL, fn, cb_data);
+       return refs_head_ref(get_main_ref_store(), fn, cb_data);
 }
 
 struct ref_iterator *refs_ref_iterator_begin(
@@ -1275,6 +1278,10 @@ struct ref_iterator *refs_ref_iterator_begin(
        if (trim)
                iter = prefix_ref_iterator_begin(iter, "", trim);
 
+       /* Sanity check for subclasses: */
+       if (!iter->ordered)
+               BUG("reference iterator is not ordered");
+
        return iter;
 }
 
@@ -1310,11 +1317,6 @@ int for_each_ref(each_ref_fn fn, void *cb_data)
        return refs_for_each_ref(get_main_ref_store(), fn, cb_data);
 }
 
-int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
-{
-       return refs_for_each_ref(get_submodule_ref_store(submodule), fn, cb_data);
-}
-
 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
                         each_ref_fn fn, void *cb_data)
 {
@@ -1336,23 +1338,15 @@ int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsig
                               prefix, fn, 0, flag, cb_data);
 }
 
-int for_each_ref_in_submodule(const char *submodule, const char *prefix,
-                             each_ref_fn fn, void *cb_data)
-{
-       return refs_for_each_ref_in(get_submodule_ref_store(submodule),
-                                   prefix, fn, cb_data);
-}
-
-int for_each_fullref_in_submodule(const char *submodule, const char *prefix,
-                                 each_ref_fn fn, void *cb_data,
-                                 unsigned int broken)
+int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
+                            each_ref_fn fn, void *cb_data,
+                            unsigned int broken)
 {
        unsigned int flag = 0;
 
        if (broken)
                flag = DO_FOR_EACH_INCLUDE_BROKEN;
-       return do_for_each_ref(get_submodule_ref_store(submodule),
-                              prefix, fn, 0, flag, cb_data);
+       return do_for_each_ref(refs, prefix, fn, 0, flag, cb_data);
 }
 
 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
@@ -1360,7 +1354,7 @@ int for_each_replace_ref(each_ref_fn fn, void *cb_data)
        return do_for_each_ref(get_main_ref_store(),
                               git_replace_ref_base, fn,
                               strlen(git_replace_ref_base),
-                              0, cb_data);
+                              DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 }
 
 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
@@ -1386,22 +1380,25 @@ int for_each_rawref(each_ref_fn fn, void *cb_data)
 }
 
 int refs_read_raw_ref(struct ref_store *ref_store,
-                     const char *refname, unsigned char *sha1,
+                     const char *refname, struct object_id *oid,
                      struct strbuf *referent, unsigned int *type)
 {
-       return ref_store->be->read_raw_ref(ref_store, refname, sha1, referent, type);
+       return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, type);
 }
 
 /* This function needs to return a meaningful errno on failure */
 const char *refs_resolve_ref_unsafe(struct ref_store *refs,
                                    const char *refname,
                                    int resolve_flags,
-                                   unsigned char *sha1, int *flags)
+                                   struct object_id *oid, int *flags)
 {
        static struct strbuf sb_refname = STRBUF_INIT;
+       struct object_id unused_oid;
        int unused_flags;
        int symref_count;
 
+       if (!oid)
+               oid = &unused_oid;
        if (!flags)
                flags = &unused_flags;
 
@@ -1429,11 +1426,24 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs,
                unsigned int read_flags = 0;
 
                if (refs_read_raw_ref(refs, refname,
-                                     sha1, &sb_refname, &read_flags)) {
+                                     oid, &sb_refname, &read_flags)) {
                        *flags |= read_flags;
-                       if (errno != ENOENT || (resolve_flags & RESOLVE_REF_READING))
+
+                       /* In reading mode, refs must eventually resolve */
+                       if (resolve_flags & RESOLVE_REF_READING)
                                return NULL;
-                       hashclr(sha1);
+
+                       /*
+                        * Otherwise a missing ref is OK. But the files backend
+                        * may show errors besides ENOENT if there are
+                        * similarly-named refs.
+                        */
+                       if (errno != ENOENT &&
+                           errno != EISDIR &&
+                           errno != ENOTDIR)
+                               return NULL;
+
+                       oidclr(oid);
                        if (*flags & REF_BAD_NAME)
                                *flags |= REF_ISBROKEN;
                        return refname;
@@ -1443,7 +1453,7 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs,
 
                if (!(read_flags & REF_ISSYMREF)) {
                        if (*flags & REF_BAD_NAME) {
-                               hashclr(sha1);
+                               oidclr(oid);
                                *flags |= REF_ISBROKEN;
                        }
                        return refname;
@@ -1451,7 +1461,7 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs,
 
                refname = sb_refname.buf;
                if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
-                       hashclr(sha1);
+                       oidclr(oid);
                        return refname;
                }
                if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
@@ -1478,40 +1488,25 @@ int refs_init_db(struct strbuf *err)
 }
 
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
-                              unsigned char *sha1, int *flags)
+                              struct object_id *oid, int *flags)
 {
        return refs_resolve_ref_unsafe(get_main_ref_store(), refname,
-                                      resolve_flags, sha1, flags);
+                                      resolve_flags, oid, flags);
 }
 
 int resolve_gitlink_ref(const char *submodule, const char *refname,
-                       unsigned char *sha1)
+                       struct object_id *oid)
 {
-       size_t len = strlen(submodule);
        struct ref_store *refs;
        int flags;
 
-       while (len && submodule[len - 1] == '/')
-               len--;
-
-       if (!len)
-               return -1;
-
-       if (submodule[len]) {
-               /* We need to strip off one or more trailing slashes */
-               char *stripped = xmemdupz(submodule, len);
-
-               refs = get_submodule_ref_store(stripped);
-               free(stripped);
-       } else {
-               refs = get_submodule_ref_store(submodule);
-       }
+       refs = get_submodule_ref_store(submodule);
 
        if (!refs)
                return -1;
 
-       if (!refs_resolve_ref_unsafe(refs, refname, 0, sha1, &flags) ||
-           is_null_sha1(sha1))
+       if (!refs_resolve_ref_unsafe(refs, refname, 0, oid, &flags) ||
+           is_null_oid(oid))
                return -1;
        return 0;
 }
@@ -1620,31 +1615,32 @@ struct ref_store *get_submodule_ref_store(const char *submodule)
 {
        struct strbuf submodule_sb = STRBUF_INIT;
        struct ref_store *refs;
-       int ret;
+       char *to_free = NULL;
+       size_t len;
 
-       if (!submodule || !*submodule) {
-               /*
-                * FIXME: This case is ideally not allowed. But that
-                * can't happen until we clean up all the callers.
-                */
-               return get_main_ref_store();
-       }
+       if (!submodule)
+               return NULL;
+
+       len = strlen(submodule);
+       while (len && is_dir_sep(submodule[len - 1]))
+               len--;
+       if (!len)
+               return NULL;
+
+       if (submodule[len])
+               /* We need to strip off one or more trailing slashes */
+               submodule = to_free = xmemdupz(submodule, len);
 
        refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
        if (refs)
-               return refs;
+               goto done;
 
        strbuf_addstr(&submodule_sb, submodule);
-       ret = is_nonbare_repository_dir(&submodule_sb);
-       strbuf_release(&submodule_sb);
-       if (!ret)
-               return NULL;
+       if (!is_nonbare_repository_dir(&submodule_sb))
+               goto done;
 
-       ret = submodule_to_gitdir(&submodule_sb, submodule);
-       if (ret) {
-               strbuf_release(&submodule_sb);
-               return NULL;
-       }
+       if (submodule_to_gitdir(&submodule_sb, submodule))
+               goto done;
 
        /* assume that add_submodule_odb() has been called */
        refs = ref_store_init(submodule_sb.buf,
@@ -1652,7 +1648,10 @@ struct ref_store *get_submodule_ref_store(const char *submodule)
        register_ref_store_map(&submodule_ref_stores, "submodule",
                               refs, submodule);
 
+done:
        strbuf_release(&submodule_sb);
+       free(to_free);
+
        return refs;
 }
 
@@ -1695,14 +1694,30 @@ int refs_pack_refs(struct ref_store *refs, unsigned int flags)
 }
 
 int refs_peel_ref(struct ref_store *refs, const char *refname,
-                 unsigned char *sha1)
+                 struct object_id *oid)
 {
-       return refs->be->peel_ref(refs, refname, sha1);
+       int flag;
+       struct object_id base;
+
+       if (current_ref_iter && current_ref_iter->refname == refname) {
+               struct object_id peeled;
+
+               if (ref_iterator_peel(current_ref_iter, &peeled))
+                       return -1;
+               oidcpy(oid, &peeled);
+               return 0;
+       }
+
+       if (refs_read_ref_full(refs, refname,
+                              RESOLVE_REF_READING, &base, &flag))
+               return -1;
+
+       return peel_object(&base, oid);
 }
 
-int peel_ref(const char *refname, unsigned char *sha1)
+int peel_ref(const char *refname, struct object_id *oid)
 {
-       return refs_peel_ref(get_main_ref_store(), refname, sha1);
+       return refs_peel_ref(get_main_ref_store(), refname, oid);
 }
 
 int refs_create_symref(struct ref_store *refs,
@@ -1862,7 +1877,7 @@ int refs_verify_refname_available(struct ref_store *refs,
                if (skip && string_list_has_string(skip, dirname.buf))
                        continue;
 
-               if (!refs_read_raw_ref(refs, dirname.buf, oid.hash, &referent, &type)) {
+               if (!refs_read_raw_ref(refs, dirname.buf, &oid, &referent, &type)) {
                        strbuf_addf(err, "'%s' exists; cannot create '%s'",
                                    dirname.buf, refname);
                        goto cleanup;
@@ -1992,19 +2007,19 @@ int delete_reflog(const char *refname)
 }
 
 int refs_reflog_expire(struct ref_store *refs,
-                      const char *refname, const unsigned char *sha1,
+                      const char *refname, const struct object_id *oid,
                       unsigned int flags,
                       reflog_expiry_prepare_fn prepare_fn,
                       reflog_expiry_should_prune_fn should_prune_fn,
                       reflog_expiry_cleanup_fn cleanup_fn,
                       void *policy_cb_data)
 {
-       return refs->be->reflog_expire(refs, refname, sha1, flags,
+       return refs->be->reflog_expire(refs, refname, oid, flags,
                                       prepare_fn, should_prune_fn,
                                       cleanup_fn, policy_cb_data);
 }
 
-int reflog_expire(const char *refname, const unsigned char *sha1,
+int reflog_expire(const char *refname, const struct object_id *oid,
                  unsigned int flags,
                  reflog_expiry_prepare_fn prepare_fn,
                  reflog_expiry_should_prune_fn should_prune_fn,
@@ -2012,7 +2027,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
                  void *policy_cb_data)
 {
        return refs_reflog_expire(get_main_ref_store(),
-                                 refname, sha1, flags,
+                                 refname, oid, flags,
                                  prepare_fn, should_prune_fn,
                                  cleanup_fn, policy_cb_data);
 }
@@ -2047,3 +2062,14 @@ int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 {
        return refs_rename_ref(get_main_ref_store(), oldref, newref, logmsg);
 }
+
+int refs_copy_existing_ref(struct ref_store *refs, const char *oldref,
+                   const char *newref, const char *logmsg)
+{
+       return refs->be->copy_ref(refs, oldref, newref, logmsg);
+}
+
+int copy_existing_ref(const char *oldref, const char *newref, const char *logmsg)
+{
+       return refs_copy_existing_ref(get_main_ref_store(), oldref, newref, logmsg);
+}