sha1_name.c: rename to use dash in file name
authorStefan Beller <sbeller@google.com>
Tue, 10 Apr 2018 21:26:19 +0000 (14:26 -0700)
committerJunio C Hamano <gitster@pobox.com>
Wed, 11 Apr 2018 09:11:00 +0000 (18:11 +0900)
This is more consistent with the project style. The majority of Git's
source files use dashes in preference to underscores in their file names.

Signed-off-by: Stefan Beller <sbeller@google.com>
Makefile
list-objects-filter.c
object.h
sha1-name.c [new file with mode: 0644]
sha1_name.c [deleted file]
index 88730d6fdd4bbae8a7b842b822f6e0faa99a4e3f..ed0ac30a16fa3ec7433f7c373954e3364a8fe4f3 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -901,7 +901,7 @@ LIB_OBJS += setup.o
 LIB_OBJS += sha1-array.o
 LIB_OBJS += sha1-lookup.o
 LIB_OBJS += sha1_file.o
-LIB_OBJS += sha1_name.o
+LIB_OBJS += sha1-name.o
 LIB_OBJS += shallow.o
 LIB_OBJS += sideband.o
 LIB_OBJS += sigchain.o
index 0ec83aaf1888903be4f1de38c8a94a594ef2130a..247717561f8fb6e2320b0128cad4325a4fca7da5 100644 (file)
@@ -19,7 +19,7 @@
  * in the traversal (until we mark it SEEN).  This is a way to
  * let us silently de-dup calls to show() in the caller.  This
  * is subtly different from the "revision.h:SHOWN" and the
- * "sha1_name.c:ONELINE_SEEN" bits.  And also different from
+ * "sha1-name.c:ONELINE_SEEN" bits.  And also different from
  * the non-de-dup usage in pack-bitmap.c
  */
 #define FILTER_SHOWN_BUT_REVISIT (1<<21)
index f13f85b2a94e3afc15debfbaf89416b5cda45acb..b8e70e55190bb918a523af0e45fac626b0290fdc 100644 (file)
--- a/object.h
+++ b/object.h
@@ -37,7 +37,7 @@ struct object_array {
  * bundle.c:                                        16
  * http-push.c:                                     16-----19
  * commit.c:                                        16-----19
- * sha1_name.c:                                              20
+ * sha1-name.c:                                              20
  * list-objects-filter.c:                                      21
  * builtin/fsck.c:           0--3
  * builtin/index-pack.c:                                     2021
diff --git a/sha1-name.c b/sha1-name.c
new file mode 100644 (file)
index 0000000..5b93bf8
--- /dev/null
@@ -0,0 +1,1734 @@
+#include "cache.h"
+#include "config.h"
+#include "tag.h"
+#include "commit.h"
+#include "tree.h"
+#include "blob.h"
+#include "tree-walk.h"
+#include "refs.h"
+#include "remote.h"
+#include "dir.h"
+#include "sha1-array.h"
+#include "packfile.h"
+#include "object-store.h"
+#include "repository.h"
+
+static int get_oid_oneline(const char *, struct object_id *, struct commit_list *);
+
+typedef int (*disambiguate_hint_fn)(const struct object_id *, void *);
+
+struct disambiguate_state {
+       int len; /* length of prefix in hex chars */
+       char hex_pfx[GIT_MAX_HEXSZ + 1];
+       struct object_id bin_pfx;
+
+       disambiguate_hint_fn fn;
+       void *cb_data;
+       struct object_id candidate;
+       unsigned candidate_exists:1;
+       unsigned candidate_checked:1;
+       unsigned candidate_ok:1;
+       unsigned disambiguate_fn_used:1;
+       unsigned ambiguous:1;
+       unsigned always_call_fn:1;
+};
+
+static void update_candidates(struct disambiguate_state *ds, const struct object_id *current)
+{
+       if (ds->always_call_fn) {
+               ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
+               return;
+       }
+       if (!ds->candidate_exists) {
+               /* this is the first candidate */
+               oidcpy(&ds->candidate, current);
+               ds->candidate_exists = 1;
+               return;
+       } else if (!oidcmp(&ds->candidate, current)) {
+               /* the same as what we already have seen */
+               return;
+       }
+
+       if (!ds->fn) {
+               /* cannot disambiguate between ds->candidate and current */
+               ds->ambiguous = 1;
+               return;
+       }
+
+       if (!ds->candidate_checked) {
+               ds->candidate_ok = ds->fn(&ds->candidate, ds->cb_data);
+               ds->disambiguate_fn_used = 1;
+               ds->candidate_checked = 1;
+       }
+
+       if (!ds->candidate_ok) {
+               /* discard the candidate; we know it does not satisfy fn */
+               oidcpy(&ds->candidate, current);
+               ds->candidate_checked = 0;
+               return;
+       }
+
+       /* if we reach this point, we know ds->candidate satisfies fn */
+       if (ds->fn(current, ds->cb_data)) {
+               /*
+                * if both current and candidate satisfy fn, we cannot
+                * disambiguate.
+                */
+               ds->candidate_ok = 0;
+               ds->ambiguous = 1;
+       }
+
+       /* otherwise, current can be discarded and candidate is still good */
+}
+
+static int append_loose_object(const struct object_id *oid, const char *path,
+                              void *data)
+{
+       oid_array_append(data, oid);
+       return 0;
+}
+
+static int match_sha(unsigned, const unsigned char *, const unsigned char *);
+
+static void find_short_object_filename(struct disambiguate_state *ds)
+{
+       int subdir_nr = ds->bin_pfx.hash[0];
+       struct alternate_object_database *alt;
+       static struct alternate_object_database *fakeent;
+
+       if (!fakeent) {
+               /*
+                * Create a "fake" alternate object database that
+                * points to our own object database, to make it
+                * easier to get a temporary working space in
+                * alt->name/alt->base while iterating over the
+                * object databases including our own.
+                */
+               fakeent = alloc_alt_odb(get_object_directory());
+       }
+       fakeent->next = the_repository->objects->alt_odb_list;
+
+       for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
+               int pos;
+
+               if (!alt->loose_objects_subdir_seen[subdir_nr]) {
+                       struct strbuf *buf = alt_scratch_buf(alt);
+                       for_each_file_in_obj_subdir(subdir_nr, buf,
+                                                   append_loose_object,
+                                                   NULL, NULL,
+                                                   &alt->loose_objects_cache);
+                       alt->loose_objects_subdir_seen[subdir_nr] = 1;
+               }
+
+               pos = oid_array_lookup(&alt->loose_objects_cache, &ds->bin_pfx);
+               if (pos < 0)
+                       pos = -1 - pos;
+               while (!ds->ambiguous && pos < alt->loose_objects_cache.nr) {
+                       const struct object_id *oid;
+                       oid = alt->loose_objects_cache.oid + pos;
+                       if (!match_sha(ds->len, ds->bin_pfx.hash, oid->hash))
+                               break;
+                       update_candidates(ds, oid);
+                       pos++;
+               }
+       }
+}
+
+static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
+{
+       do {
+               if (*a != *b)
+                       return 0;
+               a++;
+               b++;
+               len -= 2;
+       } while (len > 1);
+       if (len)
+               if ((*a ^ *b) & 0xf0)
+                       return 0;
+       return 1;
+}
+
+static void unique_in_pack(struct packed_git *p,
+                          struct disambiguate_state *ds)
+{
+       uint32_t num, i, first = 0;
+       const struct object_id *current = NULL;
+
+       if (open_pack_index(p) || !p->num_objects)
+               return;
+
+       num = p->num_objects;
+       bsearch_pack(&ds->bin_pfx, p, &first);
+
+       /*
+        * At this point, "first" is the location of the lowest object
+        * with an object name that could match "bin_pfx".  See if we have
+        * 0, 1 or more objects that actually match(es).
+        */
+       for (i = first; i < num && !ds->ambiguous; i++) {
+               struct object_id oid;
+               current = nth_packed_object_oid(&oid, p, i);
+               if (!match_sha(ds->len, ds->bin_pfx.hash, current->hash))
+                       break;
+               update_candidates(ds, current);
+       }
+}
+
+static void find_short_packed_object(struct disambiguate_state *ds)
+{
+       struct packed_git *p;
+
+       for (p = get_packed_git(the_repository); p && !ds->ambiguous;
+            p = p->next)
+               unique_in_pack(p, ds);
+}
+
+#define SHORT_NAME_NOT_FOUND (-1)
+#define SHORT_NAME_AMBIGUOUS (-2)
+
+static int finish_object_disambiguation(struct disambiguate_state *ds,
+                                       struct object_id *oid)
+{
+       if (ds->ambiguous)
+               return SHORT_NAME_AMBIGUOUS;
+
+       if (!ds->candidate_exists)
+               return SHORT_NAME_NOT_FOUND;
+
+       if (!ds->candidate_checked)
+               /*
+                * If this is the only candidate, there is no point
+                * calling the disambiguation hint callback.
+                *
+                * On the other hand, if the current candidate
+                * replaced an earlier candidate that did _not_ pass
+                * the disambiguation hint callback, then we do have
+                * more than one objects that match the short name
+                * given, so we should make sure this one matches;
+                * otherwise, if we discovered this one and the one
+                * that we previously discarded in the reverse order,
+                * we would end up showing different results in the
+                * same repository!
+                */
+               ds->candidate_ok = (!ds->disambiguate_fn_used ||
+                                   ds->fn(&ds->candidate, ds->cb_data));
+
+       if (!ds->candidate_ok)
+               return SHORT_NAME_AMBIGUOUS;
+
+       oidcpy(oid, &ds->candidate);
+       return 0;
+}
+
+static int disambiguate_commit_only(const struct object_id *oid, void *cb_data_unused)
+{
+       int kind = oid_object_info(oid, NULL);
+       return kind == OBJ_COMMIT;
+}
+
+static int disambiguate_committish_only(const struct object_id *oid, void *cb_data_unused)
+{
+       struct object *obj;
+       int kind;
+
+       kind = oid_object_info(oid, NULL);
+       if (kind == OBJ_COMMIT)
+               return 1;
+       if (kind != OBJ_TAG)
+               return 0;
+
+       /* We need to do this the hard way... */
+       obj = deref_tag(parse_object(oid), NULL, 0);
+       if (obj && obj->type == OBJ_COMMIT)
+               return 1;
+       return 0;
+}
+
+static int disambiguate_tree_only(const struct object_id *oid, void *cb_data_unused)
+{
+       int kind = oid_object_info(oid, NULL);
+       return kind == OBJ_TREE;
+}
+
+static int disambiguate_treeish_only(const struct object_id *oid, void *cb_data_unused)
+{
+       struct object *obj;
+       int kind;
+
+       kind = oid_object_info(oid, NULL);
+       if (kind == OBJ_TREE || kind == OBJ_COMMIT)
+               return 1;
+       if (kind != OBJ_TAG)
+               return 0;
+
+       /* We need to do this the hard way... */
+       obj = deref_tag(parse_object(oid), NULL, 0);
+       if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
+               return 1;
+       return 0;
+}
+
+static int disambiguate_blob_only(const struct object_id *oid, void *cb_data_unused)
+{
+       int kind = oid_object_info(oid, NULL);
+       return kind == OBJ_BLOB;
+}
+
+static disambiguate_hint_fn default_disambiguate_hint;
+
+int set_disambiguate_hint_config(const char *var, const char *value)
+{
+       static const struct {
+               const char *name;
+               disambiguate_hint_fn fn;
+       } hints[] = {
+               { "none", NULL },
+               { "commit", disambiguate_commit_only },
+               { "committish", disambiguate_committish_only },
+               { "tree", disambiguate_tree_only },
+               { "treeish", disambiguate_treeish_only },
+               { "blob", disambiguate_blob_only }
+       };
+       int i;
+
+       if (!value)
+               return config_error_nonbool(var);
+
+       for (i = 0; i < ARRAY_SIZE(hints); i++) {
+               if (!strcasecmp(value, hints[i].name)) {
+                       default_disambiguate_hint = hints[i].fn;
+                       return 0;
+               }
+       }
+
+       return error("unknown hint type for '%s': %s", var, value);
+}
+
+static int init_object_disambiguation(const char *name, int len,
+                                     struct disambiguate_state *ds)
+{
+       int i;
+
+       if (len < MINIMUM_ABBREV || len > GIT_SHA1_HEXSZ)
+               return -1;
+
+       memset(ds, 0, sizeof(*ds));
+
+       for (i = 0; i < len ;i++) {
+               unsigned char c = name[i];
+               unsigned char val;
+               if (c >= '0' && c <= '9')
+                       val = c - '0';
+               else if (c >= 'a' && c <= 'f')
+                       val = c - 'a' + 10;
+               else if (c >= 'A' && c <='F') {
+                       val = c - 'A' + 10;
+                       c -= 'A' - 'a';
+               }
+               else
+                       return -1;
+               ds->hex_pfx[i] = c;
+               if (!(i & 1))
+                       val <<= 4;
+               ds->bin_pfx.hash[i >> 1] |= val;
+       }
+
+       ds->len = len;
+       ds->hex_pfx[len] = '\0';
+       prepare_alt_odb(the_repository);
+       return 0;
+}
+
+static int show_ambiguous_object(const struct object_id *oid, void *data)
+{
+       const struct disambiguate_state *ds = data;
+       struct strbuf desc = STRBUF_INIT;
+       int type;
+
+
+       if (ds->fn && !ds->fn(oid, ds->cb_data))
+               return 0;
+
+       type = oid_object_info(oid, NULL);
+       if (type == OBJ_COMMIT) {
+               struct commit *commit = lookup_commit(oid);
+               if (commit) {
+                       struct pretty_print_context pp = {0};
+                       pp.date_mode.type = DATE_SHORT;
+                       format_commit_message(commit, " %ad - %s", &desc, &pp);
+               }
+       } else if (type == OBJ_TAG) {
+               struct tag *tag = lookup_tag(oid);
+               if (!parse_tag(tag) && tag->tag)
+                       strbuf_addf(&desc, " %s", tag->tag);
+       }
+
+       advise("  %s %s%s",
+              find_unique_abbrev(oid, DEFAULT_ABBREV),
+              type_name(type) ? type_name(type) : "unknown type",
+              desc.buf);
+
+       strbuf_release(&desc);
+       return 0;
+}
+
+static int get_short_oid(const char *name, int len, struct object_id *oid,
+                         unsigned flags)
+{
+       int status;
+       struct disambiguate_state ds;
+       int quietly = !!(flags & GET_OID_QUIETLY);
+
+       if (init_object_disambiguation(name, len, &ds) < 0)
+               return -1;
+
+       if (HAS_MULTI_BITS(flags & GET_OID_DISAMBIGUATORS))
+               die("BUG: multiple get_short_oid disambiguator flags");
+
+       if (flags & GET_OID_COMMIT)
+               ds.fn = disambiguate_commit_only;
+       else if (flags & GET_OID_COMMITTISH)
+               ds.fn = disambiguate_committish_only;
+       else if (flags & GET_OID_TREE)
+               ds.fn = disambiguate_tree_only;
+       else if (flags & GET_OID_TREEISH)
+               ds.fn = disambiguate_treeish_only;
+       else if (flags & GET_OID_BLOB)
+               ds.fn = disambiguate_blob_only;
+       else
+               ds.fn = default_disambiguate_hint;
+
+       find_short_object_filename(&ds);
+       find_short_packed_object(&ds);
+       status = finish_object_disambiguation(&ds, oid);
+
+       if (!quietly && (status == SHORT_NAME_AMBIGUOUS)) {
+               error(_("short SHA1 %s is ambiguous"), ds.hex_pfx);
+
+               /*
+                * We may still have ambiguity if we simply saw a series of
+                * candidates that did not satisfy our hint function. In
+                * that case, we still want to show them, so disable the hint
+                * function entirely.
+                */
+               if (!ds.ambiguous)
+                       ds.fn = NULL;
+
+               advise(_("The candidates are:"));
+               for_each_abbrev(ds.hex_pfx, show_ambiguous_object, &ds);
+       }
+
+       return status;
+}
+
+static int collect_ambiguous(const struct object_id *oid, void *data)
+{
+       oid_array_append(data, oid);
+       return 0;
+}
+
+int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
+{
+       struct oid_array collect = OID_ARRAY_INIT;
+       struct disambiguate_state ds;
+       int ret;
+
+       if (init_object_disambiguation(prefix, strlen(prefix), &ds) < 0)
+               return -1;
+
+       ds.always_call_fn = 1;
+       ds.fn = collect_ambiguous;
+       ds.cb_data = &collect;
+       find_short_object_filename(&ds);
+       find_short_packed_object(&ds);
+
+       ret = oid_array_for_each_unique(&collect, fn, cb_data);
+       oid_array_clear(&collect);
+       return ret;
+}
+
+/*
+ * Return the slot of the most-significant bit set in "val". There are various
+ * ways to do this quickly with fls() or __builtin_clzl(), but speed is
+ * probably not a big deal here.
+ */
+static unsigned msb(unsigned long val)
+{
+       unsigned r = 0;
+       while (val >>= 1)
+               r++;
+       return r;
+}
+
+struct min_abbrev_data {
+       unsigned int init_len;
+       unsigned int cur_len;
+       char *hex;
+       const struct object_id *oid;
+};
+
+static inline char get_hex_char_from_oid(const struct object_id *oid,
+                                        unsigned int pos)
+{
+       static const char hex[] = "0123456789abcdef";
+
+       if ((pos & 1) == 0)
+               return hex[oid->hash[pos >> 1] >> 4];
+       else
+               return hex[oid->hash[pos >> 1] & 0xf];
+}
+
+static int extend_abbrev_len(const struct object_id *oid, void *cb_data)
+{
+       struct min_abbrev_data *mad = cb_data;
+
+       unsigned int i = mad->init_len;
+       while (mad->hex[i] && mad->hex[i] == get_hex_char_from_oid(oid, i))
+               i++;
+
+       if (i < GIT_MAX_RAWSZ && i >= mad->cur_len)
+               mad->cur_len = i + 1;
+
+       return 0;
+}
+
+static void find_abbrev_len_for_pack(struct packed_git *p,
+                                    struct min_abbrev_data *mad)
+{
+       int match = 0;
+       uint32_t num, first = 0;
+       struct object_id oid;
+       const struct object_id *mad_oid;
+
+       if (open_pack_index(p) || !p->num_objects)
+               return;
+
+       num = p->num_objects;
+       mad_oid = mad->oid;
+       match = bsearch_pack(mad_oid, p, &first);
+
+       /*
+        * first is now the position in the packfile where we would insert
+        * mad->hash if it does not exist (or the position of mad->hash if
+        * it does exist). Hence, we consider a maximum of two objects
+        * nearby for the abbreviation length.
+        */
+       mad->init_len = 0;
+       if (!match) {
+               if (nth_packed_object_oid(&oid, p, first))
+                       extend_abbrev_len(&oid, mad);
+       } else if (first < num - 1) {
+               if (nth_packed_object_oid(&oid, p, first + 1))
+                       extend_abbrev_len(&oid, mad);
+       }
+       if (first > 0) {
+               if (nth_packed_object_oid(&oid, p, first - 1))
+                       extend_abbrev_len(&oid, mad);
+       }
+       mad->init_len = mad->cur_len;
+}
+
+static void find_abbrev_len_packed(struct min_abbrev_data *mad)
+{
+       struct packed_git *p;
+
+       for (p = get_packed_git(the_repository); p; p = p->next)
+               find_abbrev_len_for_pack(p, mad);
+}
+
+int find_unique_abbrev_r(char *hex, const struct object_id *oid, int len)
+{
+       struct disambiguate_state ds;
+       struct min_abbrev_data mad;
+       struct object_id oid_ret;
+       if (len < 0) {
+               unsigned long count = approximate_object_count();
+               /*
+                * Add one because the MSB only tells us the highest bit set,
+                * not including the value of all the _other_ bits (so "15"
+                * is only one off of 2^4, but the MSB is the 3rd bit.
+                */
+               len = msb(count) + 1;
+               /*
+                * We now know we have on the order of 2^len objects, which
+                * expects a collision at 2^(len/2). But we also care about hex
+                * chars, not bits, and there are 4 bits per hex. So all
+                * together we need to divide by 2 and round up.
+                */
+               len = DIV_ROUND_UP(len, 2);
+               /*
+                * For very small repos, we stick with our regular fallback.
+                */
+               if (len < FALLBACK_DEFAULT_ABBREV)
+                       len = FALLBACK_DEFAULT_ABBREV;
+       }
+
+       oid_to_hex_r(hex, oid);
+       if (len == GIT_SHA1_HEXSZ || !len)
+               return GIT_SHA1_HEXSZ;
+
+       mad.init_len = len;
+       mad.cur_len = len;
+       mad.hex = hex;
+       mad.oid = oid;
+
+       find_abbrev_len_packed(&mad);
+
+       if (init_object_disambiguation(hex, mad.cur_len, &ds) < 0)
+               return -1;
+
+       ds.fn = extend_abbrev_len;
+       ds.always_call_fn = 1;
+       ds.cb_data = (void *)&mad;
+
+       find_short_object_filename(&ds);
+       (void)finish_object_disambiguation(&ds, &oid_ret);
+
+       hex[mad.cur_len] = 0;
+       return mad.cur_len;
+}
+
+const char *find_unique_abbrev(const struct object_id *oid, int len)
+{
+       static int bufno;
+       static char hexbuffer[4][GIT_MAX_HEXSZ + 1];
+       char *hex = hexbuffer[bufno];
+       bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
+       find_unique_abbrev_r(hex, oid, len);
+       return hex;
+}
+
+static int ambiguous_path(const char *path, int len)
+{
+       int slash = 1;
+       int cnt;
+
+       for (cnt = 0; cnt < len; cnt++) {
+               switch (*path++) {
+               case '\0':
+                       break;
+               case '/':
+                       if (slash)
+                               break;
+                       slash = 1;
+                       continue;
+               case '.':
+                       continue;
+               default:
+                       slash = 0;
+                       continue;
+               }
+               break;
+       }
+       return slash;
+}
+
+static inline int at_mark(const char *string, int len,
+                         const char **suffix, int nr)
+{
+       int i;
+
+       for (i = 0; i < nr; i++) {
+               int suffix_len = strlen(suffix[i]);
+               if (suffix_len <= len
+                   && !strncasecmp(string, suffix[i], suffix_len))
+                       return suffix_len;
+       }
+       return 0;
+}
+
+static inline int upstream_mark(const char *string, int len)
+{
+       const char *suffix[] = { "@{upstream}", "@{u}" };
+       return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
+}
+
+static inline int push_mark(const char *string, int len)
+{
+       const char *suffix[] = { "@{push}" };
+       return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
+}
+
+static int get_oid_1(const char *name, int len, struct object_id *oid, unsigned lookup_flags);
+static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
+
+static int get_oid_basic(const char *str, int len, struct object_id *oid,
+                         unsigned int flags)
+{
+       static const char *warn_msg = "refname '%.*s' is ambiguous.";
+       static const char *object_name_msg = N_(
+       "Git normally never creates a ref that ends with 40 hex characters\n"
+       "because it will be ignored when you just specify 40-hex. These refs\n"
+       "may be created by mistake. For example,\n"
+       "\n"
+       "  git checkout -b $br $(git rev-parse ...)\n"
+       "\n"
+       "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
+       "examine these refs and maybe delete them. Turn this message off by\n"
+       "running \"git config advice.objectNameWarning false\"");
+       struct object_id tmp_oid;
+       char *real_ref = NULL;
+       int refs_found = 0;
+       int at, reflog_len, nth_prior = 0;
+
+       if (len == GIT_SHA1_HEXSZ && !get_oid_hex(str, oid)) {
+               if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
+                       refs_found = dwim_ref(str, len, &tmp_oid, &real_ref);
+                       if (refs_found > 0) {
+                               warning(warn_msg, len, str);
+                               if (advice_object_name_warning)
+                                       fprintf(stderr, "%s\n", _(object_name_msg));
+                       }
+                       free(real_ref);
+               }
+               return 0;
+       }
+
+       /* basic@{time or number or -number} format to query ref-log */
+       reflog_len = at = 0;
+       if (len && str[len-1] == '}') {
+               for (at = len-4; at >= 0; at--) {
+                       if (str[at] == '@' && str[at+1] == '{') {
+                               if (str[at+2] == '-') {
+                                       if (at != 0)
+                                               /* @{-N} not at start */
+                                               return -1;
+                                       nth_prior = 1;
+                                       continue;
+                               }
+                               if (!upstream_mark(str + at, len - at) &&
+                                   !push_mark(str + at, len - at)) {
+                                       reflog_len = (len-1) - (at+2);
+                                       len = at;
+                               }
+                               break;
+                       }
+               }
+       }
+
+       /* Accept only unambiguous ref paths. */
+       if (len && ambiguous_path(str, len))
+               return -1;
+
+       if (nth_prior) {
+               struct strbuf buf = STRBUF_INIT;
+               int detached;
+
+               if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
+                       detached = (buf.len == GIT_SHA1_HEXSZ && !get_oid_hex(buf.buf, oid));
+                       strbuf_release(&buf);
+                       if (detached)
+                               return 0;
+               }
+       }
+
+       if (!len && reflog_len)
+               /* allow "@{...}" to mean the current branch reflog */
+               refs_found = dwim_ref("HEAD", 4, oid, &real_ref);
+       else if (reflog_len)
+               refs_found = dwim_log(str, len, oid, &real_ref);
+       else
+               refs_found = dwim_ref(str, len, oid, &real_ref);
+
+       if (!refs_found)
+               return -1;
+
+       if (warn_ambiguous_refs && !(flags & GET_OID_QUIETLY) &&
+           (refs_found > 1 ||
+            !get_short_oid(str, len, &tmp_oid, GET_OID_QUIETLY)))
+               warning(warn_msg, len, str);
+
+       if (reflog_len) {
+               int nth, i;
+               timestamp_t at_time;
+               timestamp_t co_time;
+               int co_tz, co_cnt;
+
+               /* Is it asking for N-th entry, or approxidate? */
+               for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
+                       char ch = str[at+2+i];
+                       if ('0' <= ch && ch <= '9')
+                               nth = nth * 10 + ch - '0';
+                       else
+                               nth = -1;
+               }
+               if (100000000 <= nth) {
+                       at_time = nth;
+                       nth = -1;
+               } else if (0 <= nth)
+                       at_time = 0;
+               else {
+                       int errors = 0;
+                       char *tmp = xstrndup(str + at + 2, reflog_len);
+                       at_time = approxidate_careful(tmp, &errors);
+                       free(tmp);
+                       if (errors) {
+                               free(real_ref);
+                               return -1;
+                       }
+               }
+               if (read_ref_at(real_ref, flags, at_time, nth, oid, NULL,
+                               &co_time, &co_tz, &co_cnt)) {
+                       if (!len) {
+                               if (starts_with(real_ref, "refs/heads/")) {
+                                       str = real_ref + 11;
+                                       len = strlen(real_ref + 11);
+                               } else {
+                                       /* detached HEAD */
+                                       str = "HEAD";
+                                       len = 4;
+                               }
+                       }
+                       if (at_time) {
+                               if (!(flags & GET_OID_QUIETLY)) {
+                                       warning("Log for '%.*s' only goes "
+                                               "back to %s.", len, str,
+                                               show_date(co_time, co_tz, DATE_MODE(RFC2822)));
+                               }
+                       } else {
+                               if (flags & GET_OID_QUIETLY) {
+                                       exit(128);
+                               }
+                               die("Log for '%.*s' only has %d entries.",
+                                   len, str, co_cnt);
+                       }
+               }
+       }
+
+       free(real_ref);
+       return 0;
+}
+
+static int get_parent(const char *name, int len,
+                     struct object_id *result, int idx)
+{
+       struct object_id oid;
+       int ret = get_oid_1(name, len, &oid, GET_OID_COMMITTISH);
+       struct commit *commit;
+       struct commit_list *p;
+
+       if (ret)
+               return ret;
+       commit = lookup_commit_reference(&oid);
+       if (parse_commit(commit))
+               return -1;
+       if (!idx) {
+               oidcpy(result, &commit->object.oid);
+               return 0;
+       }
+       p = commit->parents;
+       while (p) {
+               if (!--idx) {
+                       oidcpy(result, &p->item->object.oid);
+                       return 0;
+               }
+               p = p->next;
+       }
+       return -1;
+}
+
+static int get_nth_ancestor(const char *name, int len,
+                           struct object_id *result, int generation)
+{
+       struct object_id oid;
+       struct commit *commit;
+       int ret;
+
+       ret = get_oid_1(name, len, &oid, GET_OID_COMMITTISH);
+       if (ret)
+               return ret;
+       commit = lookup_commit_reference(&oid);
+       if (!commit)
+               return -1;
+
+       while (generation--) {
+               if (parse_commit(commit) || !commit->parents)
+                       return -1;
+               commit = commit->parents->item;
+       }
+       oidcpy(result, &commit->object.oid);
+       return 0;
+}
+
+struct object *peel_to_type(const char *name, int namelen,
+                           struct object *o, enum object_type expected_type)
+{
+       if (name && !namelen)
+               namelen = strlen(name);
+       while (1) {
+               if (!o || (!o->parsed && !parse_object(&o->oid)))
+                       return NULL;
+               if (expected_type == OBJ_ANY || o->type == expected_type)
+                       return o;
+               if (o->type == OBJ_TAG)
+                       o = ((struct tag*) o)->tagged;
+               else if (o->type == OBJ_COMMIT)
+                       o = &(((struct commit *) o)->tree->object);
+               else {
+                       if (name)
+                               error("%.*s: expected %s type, but the object "
+                                     "dereferences to %s type",
+                                     namelen, name, type_name(expected_type),
+                                     type_name(o->type));
+                       return NULL;
+               }
+       }
+}
+
+static int peel_onion(const char *name, int len, struct object_id *oid,
+                     unsigned lookup_flags)
+{
+       struct object_id outer;
+       const char *sp;
+       unsigned int expected_type = 0;
+       struct object *o;
+
+       /*
+        * "ref^{type}" dereferences ref repeatedly until you cannot
+        * dereference anymore, or you get an object of given type,
+        * whichever comes first.  "ref^{}" means just dereference
+        * tags until you get a non-tag.  "ref^0" is a shorthand for
+        * "ref^{commit}".  "commit^{tree}" could be used to find the
+        * top-level tree of the given commit.
+        */
+       if (len < 4 || name[len-1] != '}')
+               return -1;
+
+       for (sp = name + len - 1; name <= sp; sp--) {
+               int ch = *sp;
+               if (ch == '{' && name < sp && sp[-1] == '^')
+                       break;
+       }
+       if (sp <= name)
+               return -1;
+
+       sp++; /* beginning of type name, or closing brace for empty */
+       if (starts_with(sp, "commit}"))
+               expected_type = OBJ_COMMIT;
+       else if (starts_with(sp, "tag}"))
+               expected_type = OBJ_TAG;
+       else if (starts_with(sp, "tree}"))
+               expected_type = OBJ_TREE;
+       else if (starts_with(sp, "blob}"))
+               expected_type = OBJ_BLOB;
+       else if (starts_with(sp, "object}"))
+               expected_type = OBJ_ANY;
+       else if (sp[0] == '}')
+               expected_type = OBJ_NONE;
+       else if (sp[0] == '/')
+               expected_type = OBJ_COMMIT;
+       else
+               return -1;
+
+       lookup_flags &= ~GET_OID_DISAMBIGUATORS;
+       if (expected_type == OBJ_COMMIT)
+               lookup_flags |= GET_OID_COMMITTISH;
+       else if (expected_type == OBJ_TREE)
+               lookup_flags |= GET_OID_TREEISH;
+
+       if (get_oid_1(name, sp - name - 2, &outer, lookup_flags))
+               return -1;
+
+       o = parse_object(&outer);
+       if (!o)
+               return -1;
+       if (!expected_type) {
+               o = deref_tag(o, name, sp - name - 2);
+               if (!o || (!o->parsed && !parse_object(&o->oid)))
+                       return -1;
+               oidcpy(oid, &o->oid);
+               return 0;
+       }
+
+       /*
+        * At this point, the syntax look correct, so
+        * if we do not get the needed object, we should
+        * barf.
+        */
+       o = peel_to_type(name, len, o, expected_type);
+       if (!o)
+               return -1;
+
+       oidcpy(oid, &o->oid);
+       if (sp[0] == '/') {
+               /* "$commit^{/foo}" */
+               char *prefix;
+               int ret;
+               struct commit_list *list = NULL;
+
+               /*
+                * $commit^{/}. Some regex implementation may reject.
+                * We don't need regex anyway. '' pattern always matches.
+                */
+               if (sp[1] == '}')
+                       return 0;
+
+               prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
+               commit_list_insert((struct commit *)o, &list);
+               ret = get_oid_oneline(prefix, oid, list);
+               free(prefix);
+               return ret;
+       }
+       return 0;
+}
+
+static int get_describe_name(const char *name, int len, struct object_id *oid)
+{
+       const char *cp;
+       unsigned flags = GET_OID_QUIETLY | GET_OID_COMMIT;
+
+       for (cp = name + len - 1; name + 2 <= cp; cp--) {
+               char ch = *cp;
+               if (!isxdigit(ch)) {
+                       /* We must be looking at g in "SOMETHING-g"
+                        * for it to be describe output.
+                        */
+                       if (ch == 'g' && cp[-1] == '-') {
+                               cp++;
+                               len -= cp - name;
+                               return get_short_oid(cp, len, oid, flags);
+                       }
+               }
+       }
+       return -1;
+}
+
+static int get_oid_1(const char *name, int len, struct object_id *oid, unsigned lookup_flags)
+{
+       int ret, has_suffix;
+       const char *cp;
+
+       /*
+        * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
+        */
+       has_suffix = 0;
+       for (cp = name + len - 1; name <= cp; cp--) {
+               int ch = *cp;
+               if ('0' <= ch && ch <= '9')
+                       continue;
+               if (ch == '~' || ch == '^')
+                       has_suffix = ch;
+               break;
+       }
+
+       if (has_suffix) {
+               int num = 0;
+               int len1 = cp - name;
+               cp++;
+               while (cp < name + len)
+                       num = num * 10 + *cp++ - '0';
+               if (!num && len1 == len - 1)
+                       num = 1;
+               if (has_suffix == '^')
+                       return get_parent(name, len1, oid, num);
+               /* else if (has_suffix == '~') -- goes without saying */
+               return get_nth_ancestor(name, len1, oid, num);
+       }
+
+       ret = peel_onion(name, len, oid, lookup_flags);
+       if (!ret)
+               return 0;
+
+       ret = get_oid_basic(name, len, oid, lookup_flags);
+       if (!ret)
+               return 0;
+
+       /* It could be describe output that is "SOMETHING-gXXXX" */
+       ret = get_describe_name(name, len, oid);
+       if (!ret)
+               return 0;
+
+       return get_short_oid(name, len, oid, lookup_flags);
+}
+
+/*
+ * This interprets names like ':/Initial revision of "git"' by searching
+ * through history and returning the first commit whose message starts
+ * the given regular expression.
+ *
+ * For negative-matching, prefix the pattern-part with '!-', like: ':/!-WIP'.
+ *
+ * For a literal '!' character at the beginning of a pattern, you have to repeat
+ * that, like: ':/!!foo'
+ *
+ * For future extension, all other sequences beginning with ':/!' are reserved.
+ */
+
+/* Remember to update object flag allocation in object.h */
+#define ONELINE_SEEN (1u<<20)
+
+static int handle_one_ref(const char *path, const struct object_id *oid,
+                         int flag, void *cb_data)
+{
+       struct commit_list **list = cb_data;
+       struct object *object = parse_object(oid);
+       if (!object)
+               return 0;
+       if (object->type == OBJ_TAG) {
+               object = deref_tag(object, path, strlen(path));
+               if (!object)
+                       return 0;
+       }
+       if (object->type != OBJ_COMMIT)
+               return 0;
+       commit_list_insert((struct commit *)object, list);
+       return 0;
+}
+
+static int get_oid_oneline(const char *prefix, struct object_id *oid,
+                           struct commit_list *list)
+{
+       struct commit_list *backup = NULL, *l;
+       int found = 0;
+       int negative = 0;
+       regex_t regex;
+
+       if (prefix[0] == '!') {
+               prefix++;
+
+               if (prefix[0] == '-') {
+                       prefix++;
+                       negative = 1;
+               } else if (prefix[0] != '!') {
+                       return -1;
+               }
+       }
+
+       if (regcomp(&regex, prefix, REG_EXTENDED))
+               return -1;
+
+       for (l = list; l; l = l->next) {
+               l->item->object.flags |= ONELINE_SEEN;
+               commit_list_insert(l->item, &backup);
+       }
+       while (list) {
+               const char *p, *buf;
+               struct commit *commit;
+               int matches;
+
+               commit = pop_most_recent_commit(&list, ONELINE_SEEN);
+               if (!parse_object(&commit->object.oid))
+                       continue;
+               buf = get_commit_buffer(commit, NULL);
+               p = strstr(buf, "\n\n");
+               matches = negative ^ (p && !regexec(&regex, p + 2, 0, NULL, 0));
+               unuse_commit_buffer(commit, buf);
+
+               if (matches) {
+                       oidcpy(oid, &commit->object.oid);
+                       found = 1;
+                       break;
+               }
+       }
+       regfree(&regex);
+       free_commit_list(list);
+       for (l = backup; l; l = l->next)
+               clear_commit_marks(l->item, ONELINE_SEEN);
+       free_commit_list(backup);
+       return found ? 0 : -1;
+}
+
+struct grab_nth_branch_switch_cbdata {
+       int remaining;
+       struct strbuf buf;
+};
+
+static int grab_nth_branch_switch(struct object_id *ooid, struct object_id *noid,
+                                 const char *email, timestamp_t timestamp, int tz,
+                                 const char *message, void *cb_data)
+{
+       struct grab_nth_branch_switch_cbdata *cb = cb_data;
+       const char *match = NULL, *target = NULL;
+       size_t len;
+
+       if (skip_prefix(message, "checkout: moving from ", &match))
+               target = strstr(match, " to ");
+
+       if (!match || !target)
+               return 0;
+       if (--(cb->remaining) == 0) {
+               len = target - match;
+               strbuf_reset(&cb->buf);
+               strbuf_add(&cb->buf, match, len);
+               return 1; /* we are done */
+       }
+       return 0;
+}
+
+/*
+ * Parse @{-N} syntax, return the number of characters parsed
+ * if successful; otherwise signal an error with negative value.
+ */
+static int interpret_nth_prior_checkout(const char *name, int namelen,
+                                       struct strbuf *buf)
+{
+       long nth;
+       int retval;
+       struct grab_nth_branch_switch_cbdata cb;
+       const char *brace;
+       char *num_end;
+
+       if (namelen < 4)
+               return -1;
+       if (name[0] != '@' || name[1] != '{' || name[2] != '-')
+               return -1;
+       brace = memchr(name, '}', namelen);
+       if (!brace)
+               return -1;
+       nth = strtol(name + 3, &num_end, 10);
+       if (num_end != brace)
+               return -1;
+       if (nth <= 0)
+               return -1;
+       cb.remaining = nth;
+       strbuf_init(&cb.buf, 20);
+
+       retval = 0;
+       if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
+               strbuf_reset(buf);
+               strbuf_addbuf(buf, &cb.buf);
+               retval = brace - name + 1;
+       }
+
+       strbuf_release(&cb.buf);
+       return retval;
+}
+
+int get_oid_mb(const char *name, struct object_id *oid)
+{
+       struct commit *one, *two;
+       struct commit_list *mbs;
+       struct object_id oid_tmp;
+       const char *dots;
+       int st;
+
+       dots = strstr(name, "...");
+       if (!dots)
+               return get_oid(name, oid);
+       if (dots == name)
+               st = get_oid("HEAD", &oid_tmp);
+       else {
+               struct strbuf sb;
+               strbuf_init(&sb, dots - name);
+               strbuf_add(&sb, name, dots - name);
+               st = get_oid_committish(sb.buf, &oid_tmp);
+               strbuf_release(&sb);
+       }
+       if (st)
+               return st;
+       one = lookup_commit_reference_gently(&oid_tmp, 0);
+       if (!one)
+               return -1;
+
+       if (get_oid_committish(dots[3] ? (dots + 3) : "HEAD", &oid_tmp))
+               return -1;
+       two = lookup_commit_reference_gently(&oid_tmp, 0);
+       if (!two)
+               return -1;
+       mbs = get_merge_bases(one, two);
+       if (!mbs || mbs->next)
+               st = -1;
+       else {
+               st = 0;
+               oidcpy(oid, &mbs->item->object.oid);
+       }
+       free_commit_list(mbs);
+       return st;
+}
+
+/* parse @something syntax, when 'something' is not {.*} */
+static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
+{
+       const char *next;
+
+       if (len || name[1] == '{')
+               return -1;
+
+       /* make sure it's a single @, or @@{.*}, not @foo */
+       next = memchr(name + len + 1, '@', namelen - len - 1);
+       if (next && next[1] != '{')
+               return -1;
+       if (!next)
+               next = name + namelen;
+       if (next != name + 1)
+               return -1;
+
+       strbuf_reset(buf);
+       strbuf_add(buf, "HEAD", 4);
+       return 1;
+}
+
+static int reinterpret(const char *name, int namelen, int len,
+                      struct strbuf *buf, unsigned allowed)
+{
+       /* we have extra data, which might need further processing */
+       struct strbuf tmp = STRBUF_INIT;
+       int used = buf->len;
+       int ret;
+
+       strbuf_add(buf, name + len, namelen - len);
+       ret = interpret_branch_name(buf->buf, buf->len, &tmp, allowed);
+       /* that data was not interpreted, remove our cruft */
+       if (ret < 0) {
+               strbuf_setlen(buf, used);
+               return len;
+       }
+       strbuf_reset(buf);
+       strbuf_addbuf(buf, &tmp);
+       strbuf_release(&tmp);
+       /* tweak for size of {-N} versus expanded ref name */
+       return ret - used + len;
+}
+
+static void set_shortened_ref(struct strbuf *buf, const char *ref)
+{
+       char *s = shorten_unambiguous_ref(ref, 0);
+       strbuf_reset(buf);
+       strbuf_addstr(buf, s);
+       free(s);
+}
+
+static int branch_interpret_allowed(const char *refname, unsigned allowed)
+{
+       if (!allowed)
+               return 1;
+
+       if ((allowed & INTERPRET_BRANCH_LOCAL) &&
+           starts_with(refname, "refs/heads/"))
+               return 1;
+       if ((allowed & INTERPRET_BRANCH_REMOTE) &&
+           starts_with(refname, "refs/remotes/"))
+               return 1;
+
+       return 0;
+}
+
+static int interpret_branch_mark(const char *name, int namelen,
+                                int at, struct strbuf *buf,
+                                int (*get_mark)(const char *, int),
+                                const char *(*get_data)(struct branch *,
+                                                        struct strbuf *),
+                                unsigned allowed)
+{
+       int len;
+       struct branch *branch;
+       struct strbuf err = STRBUF_INIT;
+       const char *value;
+
+       len = get_mark(name + at, namelen - at);
+       if (!len)
+               return -1;
+
+       if (memchr(name, ':', at))
+               return -1;
+
+       if (at) {
+               char *name_str = xmemdupz(name, at);
+               branch = branch_get(name_str);
+               free(name_str);
+       } else
+               branch = branch_get(NULL);
+
+       value = get_data(branch, &err);
+       if (!value)
+               die("%s", err.buf);
+
+       if (!branch_interpret_allowed(value, allowed))
+               return -1;
+
+       set_shortened_ref(buf, value);
+       return len + at;
+}
+
+int interpret_branch_name(const char *name, int namelen, struct strbuf *buf,
+                         unsigned allowed)
+{
+       char *at;
+       const char *start;
+       int len;
+
+       if (!namelen)
+               namelen = strlen(name);
+
+       if (!allowed || (allowed & INTERPRET_BRANCH_LOCAL)) {
+               len = interpret_nth_prior_checkout(name, namelen, buf);
+               if (!len) {
+                       return len; /* syntax Ok, not enough switches */
+               } else if (len > 0) {
+                       if (len == namelen)
+                               return len; /* consumed all */
+                       else
+                               return reinterpret(name, namelen, len, buf, allowed);
+               }
+       }
+
+       for (start = name;
+            (at = memchr(start, '@', namelen - (start - name)));
+            start = at + 1) {
+
+               if (!allowed || (allowed & INTERPRET_BRANCH_HEAD)) {
+                       len = interpret_empty_at(name, namelen, at - name, buf);
+                       if (len > 0)
+                               return reinterpret(name, namelen, len, buf,
+                                                  allowed);
+               }
+
+               len = interpret_branch_mark(name, namelen, at - name, buf,
+                                           upstream_mark, branch_get_upstream,
+                                           allowed);
+               if (len > 0)
+                       return len;
+
+               len = interpret_branch_mark(name, namelen, at - name, buf,
+                                           push_mark, branch_get_push,
+                                           allowed);
+               if (len > 0)
+                       return len;
+       }
+
+       return -1;
+}
+
+void strbuf_branchname(struct strbuf *sb, const char *name, unsigned allowed)
+{
+       int len = strlen(name);
+       int used = interpret_branch_name(name, len, sb, allowed);
+
+       if (used < 0)
+               used = 0;
+       strbuf_add(sb, name + used, len - used);
+}
+
+int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
+{
+       if (startup_info->have_repository)
+               strbuf_branchname(sb, name, INTERPRET_BRANCH_LOCAL);
+       else
+               strbuf_addstr(sb, name);
+
+       /*
+        * This splice must be done even if we end up rejecting the
+        * name; builtin/branch.c::copy_or_rename_branch() still wants
+        * to see what the name expanded to so that "branch -m" can be
+        * used as a tool to correct earlier mistakes.
+        */
+       strbuf_splice(sb, 0, 0, "refs/heads/", 11);
+
+       if (*name == '-' ||
+           !strcmp(sb->buf, "refs/heads/HEAD"))
+               return -1;
+
+       return check_refname_format(sb->buf, 0);
+}
+
+/*
+ * This is like "get_oid_basic()", except it allows "object ID expressions",
+ * notably "xyz^" for "parent of xyz"
+ */
+int get_oid(const char *name, struct object_id *oid)
+{
+       struct object_context unused;
+       return get_oid_with_context(name, 0, oid, &unused);
+}
+
+
+/*
+ * Many callers know that the user meant to name a commit-ish by
+ * syntactical positions where the object name appears.  Calling this
+ * function allows the machinery to disambiguate shorter-than-unique
+ * abbreviated object names between commit-ish and others.
+ *
+ * Note that this does NOT error out when the named object is not a
+ * commit-ish. It is merely to give a hint to the disambiguation
+ * machinery.
+ */
+int get_oid_committish(const char *name, struct object_id *oid)
+{
+       struct object_context unused;
+       return get_oid_with_context(name, GET_OID_COMMITTISH,
+                                   oid, &unused);
+}
+
+int get_oid_treeish(const char *name, struct object_id *oid)
+{
+       struct object_context unused;
+       return get_oid_with_context(name, GET_OID_TREEISH,
+                                   oid, &unused);
+}
+
+int get_oid_commit(const char *name, struct object_id *oid)
+{
+       struct object_context unused;
+       return get_oid_with_context(name, GET_OID_COMMIT,
+                                   oid, &unused);
+}
+
+int get_oid_tree(const char *name, struct object_id *oid)
+{
+       struct object_context unused;
+       return get_oid_with_context(name, GET_OID_TREE,
+                                   oid, &unused);
+}
+
+int get_oid_blob(const char *name, struct object_id *oid)
+{
+       struct object_context unused;
+       return get_oid_with_context(name, GET_OID_BLOB,
+                                   oid, &unused);
+}
+
+/* Must be called only when object_name:filename doesn't exist. */
+static void diagnose_invalid_oid_path(const char *prefix,
+                                     const char *filename,
+                                     const struct object_id *tree_oid,
+                                     const char *object_name,
+                                     int object_name_len)
+{
+       struct object_id oid;
+       unsigned mode;
+
+       if (!prefix)
+               prefix = "";
+
+       if (file_exists(filename))
+               die("Path '%s' exists on disk, but not in '%.*s'.",
+                   filename, object_name_len, object_name);
+       if (is_missing_file_error(errno)) {
+               char *fullname = xstrfmt("%s%s", prefix, filename);
+
+               if (!get_tree_entry(tree_oid, fullname, &oid, &mode)) {
+                       die("Path '%s' exists, but not '%s'.\n"
+                           "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
+                           fullname,
+                           filename,
+                           object_name_len, object_name,
+                           fullname,
+                           object_name_len, object_name,
+                           filename);
+               }
+               die("Path '%s' does not exist in '%.*s'",
+                   filename, object_name_len, object_name);
+       }
+}
+
+/* Must be called only when :stage:filename doesn't exist. */
+static void diagnose_invalid_index_path(int stage,
+                                       const char *prefix,
+                                       const char *filename)
+{
+       const struct cache_entry *ce;
+       int pos;
+       unsigned namelen = strlen(filename);
+       struct strbuf fullname = STRBUF_INIT;
+
+       if (!prefix)
+               prefix = "";
+
+       /* Wrong stage number? */
+       pos = cache_name_pos(filename, namelen);
+       if (pos < 0)
+               pos = -pos - 1;
+       if (pos < active_nr) {
+               ce = active_cache[pos];
+               if (ce_namelen(ce) == namelen &&
+                   !memcmp(ce->name, filename, namelen))
+                       die("Path '%s' is in the index, but not at stage %d.\n"
+                           "Did you mean ':%d:%s'?",
+                           filename, stage,
+                           ce_stage(ce), filename);
+       }
+
+       /* Confusion between relative and absolute filenames? */
+       strbuf_addstr(&fullname, prefix);
+       strbuf_addstr(&fullname, filename);
+       pos = cache_name_pos(fullname.buf, fullname.len);
+       if (pos < 0)
+               pos = -pos - 1;
+       if (pos < active_nr) {
+               ce = active_cache[pos];
+               if (ce_namelen(ce) == fullname.len &&
+                   !memcmp(ce->name, fullname.buf, fullname.len))
+                       die("Path '%s' is in the index, but not '%s'.\n"
+                           "Did you mean ':%d:%s' aka ':%d:./%s'?",
+                           fullname.buf, filename,
+                           ce_stage(ce), fullname.buf,
+                           ce_stage(ce), filename);
+       }
+
+       if (file_exists(filename))
+               die("Path '%s' exists on disk, but not in the index.", filename);
+       if (is_missing_file_error(errno))
+               die("Path '%s' does not exist (neither on disk nor in the index).",
+                   filename);
+
+       strbuf_release(&fullname);
+}
+
+
+static char *resolve_relative_path(const char *rel)
+{
+       if (!starts_with(rel, "./") && !starts_with(rel, "../"))
+               return NULL;
+
+       if (!is_inside_work_tree())
+               die("relative path syntax can't be used outside working tree.");
+
+       /* die() inside prefix_path() if resolved path is outside worktree */
+       return prefix_path(startup_info->prefix,
+                          startup_info->prefix ? strlen(startup_info->prefix) : 0,
+                          rel);
+}
+
+static int get_oid_with_context_1(const char *name,
+                                 unsigned flags,
+                                 const char *prefix,
+                                 struct object_id *oid,
+                                 struct object_context *oc)
+{
+       int ret, bracket_depth;
+       int namelen = strlen(name);
+       const char *cp;
+       int only_to_die = flags & GET_OID_ONLY_TO_DIE;
+
+       if (only_to_die)
+               flags |= GET_OID_QUIETLY;
+
+       memset(oc, 0, sizeof(*oc));
+       oc->mode = S_IFINVALID;
+       strbuf_init(&oc->symlink_path, 0);
+       ret = get_oid_1(name, namelen, oid, flags);
+       if (!ret)
+               return ret;
+       /*
+        * sha1:path --> object name of path in ent sha1
+        * :path -> object name of absolute path in index
+        * :./path -> object name of path relative to cwd in index
+        * :[0-3]:path -> object name of path in index at stage
+        * :/foo -> recent commit matching foo
+        */
+       if (name[0] == ':') {
+               int stage = 0;
+               const struct cache_entry *ce;
+               char *new_path = NULL;
+               int pos;
+               if (!only_to_die && namelen > 2 && name[1] == '/') {
+                       struct commit_list *list = NULL;
+
+                       for_each_ref(handle_one_ref, &list);
+                       commit_list_sort_by_date(&list);
+                       return get_oid_oneline(name + 2, oid, list);
+               }
+               if (namelen < 3 ||
+                   name[2] != ':' ||
+                   name[1] < '0' || '3' < name[1])
+                       cp = name + 1;
+               else {
+                       stage = name[1] - '0';
+                       cp = name + 3;
+               }
+               new_path = resolve_relative_path(cp);
+               if (!new_path) {
+                       namelen = namelen - (cp - name);
+               } else {
+                       cp = new_path;
+                       namelen = strlen(cp);
+               }
+
+               if (flags & GET_OID_RECORD_PATH)
+                       oc->path = xstrdup(cp);
+
+               if (!active_cache)
+                       read_cache();
+               pos = cache_name_pos(cp, namelen);
+               if (pos < 0)
+                       pos = -pos - 1;
+               while (pos < active_nr) {
+                       ce = active_cache[pos];
+                       if (ce_namelen(ce) != namelen ||
+                           memcmp(ce->name, cp, namelen))
+                               break;
+                       if (ce_stage(ce) == stage) {
+                               oidcpy(oid, &ce->oid);
+                               oc->mode = ce->ce_mode;
+                               free(new_path);
+                               return 0;
+                       }
+                       pos++;
+               }
+               if (only_to_die && name[1] && name[1] != '/')
+                       diagnose_invalid_index_path(stage, prefix, cp);
+               free(new_path);
+               return -1;
+       }
+       for (cp = name, bracket_depth = 0; *cp; cp++) {
+               if (*cp == '{')
+                       bracket_depth++;
+               else if (bracket_depth && *cp == '}')
+                       bracket_depth--;
+               else if (!bracket_depth && *cp == ':')
+                       break;
+       }
+       if (*cp == ':') {
+               struct object_id tree_oid;
+               int len = cp - name;
+               unsigned sub_flags = flags;
+
+               sub_flags &= ~GET_OID_DISAMBIGUATORS;
+               sub_flags |= GET_OID_TREEISH;
+
+               if (!get_oid_1(name, len, &tree_oid, sub_flags)) {
+                       const char *filename = cp+1;
+                       char *new_filename = NULL;
+
+                       new_filename = resolve_relative_path(filename);
+                       if (new_filename)
+                               filename = new_filename;
+                       if (flags & GET_OID_FOLLOW_SYMLINKS) {
+                               ret = get_tree_entry_follow_symlinks(tree_oid.hash,
+                                       filename, oid->hash, &oc->symlink_path,
+                                       &oc->mode);
+                       } else {
+                               ret = get_tree_entry(&tree_oid, filename, oid,
+                                                    &oc->mode);
+                               if (ret && only_to_die) {
+                                       diagnose_invalid_oid_path(prefix,
+                                                                  filename,
+                                                                  &tree_oid,
+                                                                  name, len);
+                               }
+                       }
+                       hashcpy(oc->tree, tree_oid.hash);
+                       if (flags & GET_OID_RECORD_PATH)
+                               oc->path = xstrdup(filename);
+
+                       free(new_filename);
+                       return ret;
+               } else {
+                       if (only_to_die)
+                               die("Invalid object name '%.*s'.", len, name);
+               }
+       }
+       return ret;
+}
+
+/*
+ * Call this function when you know "name" given by the end user must
+ * name an object but it doesn't; the function _may_ die with a better
+ * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
+ * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
+ * you have a chance to diagnose the error further.
+ */
+void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
+{
+       struct object_context oc;
+       struct object_id oid;
+       get_oid_with_context_1(name, GET_OID_ONLY_TO_DIE, prefix, &oid, &oc);
+}
+
+int get_oid_with_context(const char *str, unsigned flags, struct object_id *oid, struct object_context *oc)
+{
+       if (flags & GET_OID_FOLLOW_SYMLINKS && flags & GET_OID_ONLY_TO_DIE)
+               die("BUG: incompatible flags for get_sha1_with_context");
+       return get_oid_with_context_1(str, flags, NULL, oid, oc);
+}
diff --git a/sha1_name.c b/sha1_name.c
deleted file mode 100644 (file)
index 5b93bf8..0000000
+++ /dev/null
@@ -1,1734 +0,0 @@
-#include "cache.h"
-#include "config.h"
-#include "tag.h"
-#include "commit.h"
-#include "tree.h"
-#include "blob.h"
-#include "tree-walk.h"
-#include "refs.h"
-#include "remote.h"
-#include "dir.h"
-#include "sha1-array.h"
-#include "packfile.h"
-#include "object-store.h"
-#include "repository.h"
-
-static int get_oid_oneline(const char *, struct object_id *, struct commit_list *);
-
-typedef int (*disambiguate_hint_fn)(const struct object_id *, void *);
-
-struct disambiguate_state {
-       int len; /* length of prefix in hex chars */
-       char hex_pfx[GIT_MAX_HEXSZ + 1];
-       struct object_id bin_pfx;
-
-       disambiguate_hint_fn fn;
-       void *cb_data;
-       struct object_id candidate;
-       unsigned candidate_exists:1;
-       unsigned candidate_checked:1;
-       unsigned candidate_ok:1;
-       unsigned disambiguate_fn_used:1;
-       unsigned ambiguous:1;
-       unsigned always_call_fn:1;
-};
-
-static void update_candidates(struct disambiguate_state *ds, const struct object_id *current)
-{
-       if (ds->always_call_fn) {
-               ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
-               return;
-       }
-       if (!ds->candidate_exists) {
-               /* this is the first candidate */
-               oidcpy(&ds->candidate, current);
-               ds->candidate_exists = 1;
-               return;
-       } else if (!oidcmp(&ds->candidate, current)) {
-               /* the same as what we already have seen */
-               return;
-       }
-
-       if (!ds->fn) {
-               /* cannot disambiguate between ds->candidate and current */
-               ds->ambiguous = 1;
-               return;
-       }
-
-       if (!ds->candidate_checked) {
-               ds->candidate_ok = ds->fn(&ds->candidate, ds->cb_data);
-               ds->disambiguate_fn_used = 1;
-               ds->candidate_checked = 1;
-       }
-
-       if (!ds->candidate_ok) {
-               /* discard the candidate; we know it does not satisfy fn */
-               oidcpy(&ds->candidate, current);
-               ds->candidate_checked = 0;
-               return;
-       }
-
-       /* if we reach this point, we know ds->candidate satisfies fn */
-       if (ds->fn(current, ds->cb_data)) {
-               /*
-                * if both current and candidate satisfy fn, we cannot
-                * disambiguate.
-                */
-               ds->candidate_ok = 0;
-               ds->ambiguous = 1;
-       }
-
-       /* otherwise, current can be discarded and candidate is still good */
-}
-
-static int append_loose_object(const struct object_id *oid, const char *path,
-                              void *data)
-{
-       oid_array_append(data, oid);
-       return 0;
-}
-
-static int match_sha(unsigned, const unsigned char *, const unsigned char *);
-
-static void find_short_object_filename(struct disambiguate_state *ds)
-{
-       int subdir_nr = ds->bin_pfx.hash[0];
-       struct alternate_object_database *alt;
-       static struct alternate_object_database *fakeent;
-
-       if (!fakeent) {
-               /*
-                * Create a "fake" alternate object database that
-                * points to our own object database, to make it
-                * easier to get a temporary working space in
-                * alt->name/alt->base while iterating over the
-                * object databases including our own.
-                */
-               fakeent = alloc_alt_odb(get_object_directory());
-       }
-       fakeent->next = the_repository->objects->alt_odb_list;
-
-       for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
-               int pos;
-
-               if (!alt->loose_objects_subdir_seen[subdir_nr]) {
-                       struct strbuf *buf = alt_scratch_buf(alt);
-                       for_each_file_in_obj_subdir(subdir_nr, buf,
-                                                   append_loose_object,
-                                                   NULL, NULL,
-                                                   &alt->loose_objects_cache);
-                       alt->loose_objects_subdir_seen[subdir_nr] = 1;
-               }
-
-               pos = oid_array_lookup(&alt->loose_objects_cache, &ds->bin_pfx);
-               if (pos < 0)
-                       pos = -1 - pos;
-               while (!ds->ambiguous && pos < alt->loose_objects_cache.nr) {
-                       const struct object_id *oid;
-                       oid = alt->loose_objects_cache.oid + pos;
-                       if (!match_sha(ds->len, ds->bin_pfx.hash, oid->hash))
-                               break;
-                       update_candidates(ds, oid);
-                       pos++;
-               }
-       }
-}
-
-static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
-{
-       do {
-               if (*a != *b)
-                       return 0;
-               a++;
-               b++;
-               len -= 2;
-       } while (len > 1);
-       if (len)
-               if ((*a ^ *b) & 0xf0)
-                       return 0;
-       return 1;
-}
-
-static void unique_in_pack(struct packed_git *p,
-                          struct disambiguate_state *ds)
-{
-       uint32_t num, i, first = 0;
-       const struct object_id *current = NULL;
-
-       if (open_pack_index(p) || !p->num_objects)
-               return;
-
-       num = p->num_objects;
-       bsearch_pack(&ds->bin_pfx, p, &first);
-
-       /*
-        * At this point, "first" is the location of the lowest object
-        * with an object name that could match "bin_pfx".  See if we have
-        * 0, 1 or more objects that actually match(es).
-        */
-       for (i = first; i < num && !ds->ambiguous; i++) {
-               struct object_id oid;
-               current = nth_packed_object_oid(&oid, p, i);
-               if (!match_sha(ds->len, ds->bin_pfx.hash, current->hash))
-                       break;
-               update_candidates(ds, current);
-       }
-}
-
-static void find_short_packed_object(struct disambiguate_state *ds)
-{
-       struct packed_git *p;
-
-       for (p = get_packed_git(the_repository); p && !ds->ambiguous;
-            p = p->next)
-               unique_in_pack(p, ds);
-}
-
-#define SHORT_NAME_NOT_FOUND (-1)
-#define SHORT_NAME_AMBIGUOUS (-2)
-
-static int finish_object_disambiguation(struct disambiguate_state *ds,
-                                       struct object_id *oid)
-{
-       if (ds->ambiguous)
-               return SHORT_NAME_AMBIGUOUS;
-
-       if (!ds->candidate_exists)
-               return SHORT_NAME_NOT_FOUND;
-
-       if (!ds->candidate_checked)
-               /*
-                * If this is the only candidate, there is no point
-                * calling the disambiguation hint callback.
-                *
-                * On the other hand, if the current candidate
-                * replaced an earlier candidate that did _not_ pass
-                * the disambiguation hint callback, then we do have
-                * more than one objects that match the short name
-                * given, so we should make sure this one matches;
-                * otherwise, if we discovered this one and the one
-                * that we previously discarded in the reverse order,
-                * we would end up showing different results in the
-                * same repository!
-                */
-               ds->candidate_ok = (!ds->disambiguate_fn_used ||
-                                   ds->fn(&ds->candidate, ds->cb_data));
-
-       if (!ds->candidate_ok)
-               return SHORT_NAME_AMBIGUOUS;
-
-       oidcpy(oid, &ds->candidate);
-       return 0;
-}
-
-static int disambiguate_commit_only(const struct object_id *oid, void *cb_data_unused)
-{
-       int kind = oid_object_info(oid, NULL);
-       return kind == OBJ_COMMIT;
-}
-
-static int disambiguate_committish_only(const struct object_id *oid, void *cb_data_unused)
-{
-       struct object *obj;
-       int kind;
-
-       kind = oid_object_info(oid, NULL);
-       if (kind == OBJ_COMMIT)
-               return 1;
-       if (kind != OBJ_TAG)
-               return 0;
-
-       /* We need to do this the hard way... */
-       obj = deref_tag(parse_object(oid), NULL, 0);
-       if (obj && obj->type == OBJ_COMMIT)
-               return 1;
-       return 0;
-}
-
-static int disambiguate_tree_only(const struct object_id *oid, void *cb_data_unused)
-{
-       int kind = oid_object_info(oid, NULL);
-       return kind == OBJ_TREE;
-}
-
-static int disambiguate_treeish_only(const struct object_id *oid, void *cb_data_unused)
-{
-       struct object *obj;
-       int kind;
-
-       kind = oid_object_info(oid, NULL);
-       if (kind == OBJ_TREE || kind == OBJ_COMMIT)
-               return 1;
-       if (kind != OBJ_TAG)
-               return 0;
-
-       /* We need to do this the hard way... */
-       obj = deref_tag(parse_object(oid), NULL, 0);
-       if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
-               return 1;
-       return 0;
-}
-
-static int disambiguate_blob_only(const struct object_id *oid, void *cb_data_unused)
-{
-       int kind = oid_object_info(oid, NULL);
-       return kind == OBJ_BLOB;
-}
-
-static disambiguate_hint_fn default_disambiguate_hint;
-
-int set_disambiguate_hint_config(const char *var, const char *value)
-{
-       static const struct {
-               const char *name;
-               disambiguate_hint_fn fn;
-       } hints[] = {
-               { "none", NULL },
-               { "commit", disambiguate_commit_only },
-               { "committish", disambiguate_committish_only },
-               { "tree", disambiguate_tree_only },
-               { "treeish", disambiguate_treeish_only },
-               { "blob", disambiguate_blob_only }
-       };
-       int i;
-
-       if (!value)
-               return config_error_nonbool(var);
-
-       for (i = 0; i < ARRAY_SIZE(hints); i++) {
-               if (!strcasecmp(value, hints[i].name)) {
-                       default_disambiguate_hint = hints[i].fn;
-                       return 0;
-               }
-       }
-
-       return error("unknown hint type for '%s': %s", var, value);
-}
-
-static int init_object_disambiguation(const char *name, int len,
-                                     struct disambiguate_state *ds)
-{
-       int i;
-
-       if (len < MINIMUM_ABBREV || len > GIT_SHA1_HEXSZ)
-               return -1;
-
-       memset(ds, 0, sizeof(*ds));
-
-       for (i = 0; i < len ;i++) {
-               unsigned char c = name[i];
-               unsigned char val;
-               if (c >= '0' && c <= '9')
-                       val = c - '0';
-               else if (c >= 'a' && c <= 'f')
-                       val = c - 'a' + 10;
-               else if (c >= 'A' && c <='F') {
-                       val = c - 'A' + 10;
-                       c -= 'A' - 'a';
-               }
-               else
-                       return -1;
-               ds->hex_pfx[i] = c;
-               if (!(i & 1))
-                       val <<= 4;
-               ds->bin_pfx.hash[i >> 1] |= val;
-       }
-
-       ds->len = len;
-       ds->hex_pfx[len] = '\0';
-       prepare_alt_odb(the_repository);
-       return 0;
-}
-
-static int show_ambiguous_object(const struct object_id *oid, void *data)
-{
-       const struct disambiguate_state *ds = data;
-       struct strbuf desc = STRBUF_INIT;
-       int type;
-
-
-       if (ds->fn && !ds->fn(oid, ds->cb_data))
-               return 0;
-
-       type = oid_object_info(oid, NULL);
-       if (type == OBJ_COMMIT) {
-               struct commit *commit = lookup_commit(oid);
-               if (commit) {
-                       struct pretty_print_context pp = {0};
-                       pp.date_mode.type = DATE_SHORT;
-                       format_commit_message(commit, " %ad - %s", &desc, &pp);
-               }
-       } else if (type == OBJ_TAG) {
-               struct tag *tag = lookup_tag(oid);
-               if (!parse_tag(tag) && tag->tag)
-                       strbuf_addf(&desc, " %s", tag->tag);
-       }
-
-       advise("  %s %s%s",
-              find_unique_abbrev(oid, DEFAULT_ABBREV),
-              type_name(type) ? type_name(type) : "unknown type",
-              desc.buf);
-
-       strbuf_release(&desc);
-       return 0;
-}
-
-static int get_short_oid(const char *name, int len, struct object_id *oid,
-                         unsigned flags)
-{
-       int status;
-       struct disambiguate_state ds;
-       int quietly = !!(flags & GET_OID_QUIETLY);
-
-       if (init_object_disambiguation(name, len, &ds) < 0)
-               return -1;
-
-       if (HAS_MULTI_BITS(flags & GET_OID_DISAMBIGUATORS))
-               die("BUG: multiple get_short_oid disambiguator flags");
-
-       if (flags & GET_OID_COMMIT)
-               ds.fn = disambiguate_commit_only;
-       else if (flags & GET_OID_COMMITTISH)
-               ds.fn = disambiguate_committish_only;
-       else if (flags & GET_OID_TREE)
-               ds.fn = disambiguate_tree_only;
-       else if (flags & GET_OID_TREEISH)
-               ds.fn = disambiguate_treeish_only;
-       else if (flags & GET_OID_BLOB)
-               ds.fn = disambiguate_blob_only;
-       else
-               ds.fn = default_disambiguate_hint;
-
-       find_short_object_filename(&ds);
-       find_short_packed_object(&ds);
-       status = finish_object_disambiguation(&ds, oid);
-
-       if (!quietly && (status == SHORT_NAME_AMBIGUOUS)) {
-               error(_("short SHA1 %s is ambiguous"), ds.hex_pfx);
-
-               /*
-                * We may still have ambiguity if we simply saw a series of
-                * candidates that did not satisfy our hint function. In
-                * that case, we still want to show them, so disable the hint
-                * function entirely.
-                */
-               if (!ds.ambiguous)
-                       ds.fn = NULL;
-
-               advise(_("The candidates are:"));
-               for_each_abbrev(ds.hex_pfx, show_ambiguous_object, &ds);
-       }
-
-       return status;
-}
-
-static int collect_ambiguous(const struct object_id *oid, void *data)
-{
-       oid_array_append(data, oid);
-       return 0;
-}
-
-int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
-{
-       struct oid_array collect = OID_ARRAY_INIT;
-       struct disambiguate_state ds;
-       int ret;
-
-       if (init_object_disambiguation(prefix, strlen(prefix), &ds) < 0)
-               return -1;
-
-       ds.always_call_fn = 1;
-       ds.fn = collect_ambiguous;
-       ds.cb_data = &collect;
-       find_short_object_filename(&ds);
-       find_short_packed_object(&ds);
-
-       ret = oid_array_for_each_unique(&collect, fn, cb_data);
-       oid_array_clear(&collect);
-       return ret;
-}
-
-/*
- * Return the slot of the most-significant bit set in "val". There are various
- * ways to do this quickly with fls() or __builtin_clzl(), but speed is
- * probably not a big deal here.
- */
-static unsigned msb(unsigned long val)
-{
-       unsigned r = 0;
-       while (val >>= 1)
-               r++;
-       return r;
-}
-
-struct min_abbrev_data {
-       unsigned int init_len;
-       unsigned int cur_len;
-       char *hex;
-       const struct object_id *oid;
-};
-
-static inline char get_hex_char_from_oid(const struct object_id *oid,
-                                        unsigned int pos)
-{
-       static const char hex[] = "0123456789abcdef";
-
-       if ((pos & 1) == 0)
-               return hex[oid->hash[pos >> 1] >> 4];
-       else
-               return hex[oid->hash[pos >> 1] & 0xf];
-}
-
-static int extend_abbrev_len(const struct object_id *oid, void *cb_data)
-{
-       struct min_abbrev_data *mad = cb_data;
-
-       unsigned int i = mad->init_len;
-       while (mad->hex[i] && mad->hex[i] == get_hex_char_from_oid(oid, i))
-               i++;
-
-       if (i < GIT_MAX_RAWSZ && i >= mad->cur_len)
-               mad->cur_len = i + 1;
-
-       return 0;
-}
-
-static void find_abbrev_len_for_pack(struct packed_git *p,
-                                    struct min_abbrev_data *mad)
-{
-       int match = 0;
-       uint32_t num, first = 0;
-       struct object_id oid;
-       const struct object_id *mad_oid;
-
-       if (open_pack_index(p) || !p->num_objects)
-               return;
-
-       num = p->num_objects;
-       mad_oid = mad->oid;
-       match = bsearch_pack(mad_oid, p, &first);
-
-       /*
-        * first is now the position in the packfile where we would insert
-        * mad->hash if it does not exist (or the position of mad->hash if
-        * it does exist). Hence, we consider a maximum of two objects
-        * nearby for the abbreviation length.
-        */
-       mad->init_len = 0;
-       if (!match) {
-               if (nth_packed_object_oid(&oid, p, first))
-                       extend_abbrev_len(&oid, mad);
-       } else if (first < num - 1) {
-               if (nth_packed_object_oid(&oid, p, first + 1))
-                       extend_abbrev_len(&oid, mad);
-       }
-       if (first > 0) {
-               if (nth_packed_object_oid(&oid, p, first - 1))
-                       extend_abbrev_len(&oid, mad);
-       }
-       mad->init_len = mad->cur_len;
-}
-
-static void find_abbrev_len_packed(struct min_abbrev_data *mad)
-{
-       struct packed_git *p;
-
-       for (p = get_packed_git(the_repository); p; p = p->next)
-               find_abbrev_len_for_pack(p, mad);
-}
-
-int find_unique_abbrev_r(char *hex, const struct object_id *oid, int len)
-{
-       struct disambiguate_state ds;
-       struct min_abbrev_data mad;
-       struct object_id oid_ret;
-       if (len < 0) {
-               unsigned long count = approximate_object_count();
-               /*
-                * Add one because the MSB only tells us the highest bit set,
-                * not including the value of all the _other_ bits (so "15"
-                * is only one off of 2^4, but the MSB is the 3rd bit.
-                */
-               len = msb(count) + 1;
-               /*
-                * We now know we have on the order of 2^len objects, which
-                * expects a collision at 2^(len/2). But we also care about hex
-                * chars, not bits, and there are 4 bits per hex. So all
-                * together we need to divide by 2 and round up.
-                */
-               len = DIV_ROUND_UP(len, 2);
-               /*
-                * For very small repos, we stick with our regular fallback.
-                */
-               if (len < FALLBACK_DEFAULT_ABBREV)
-                       len = FALLBACK_DEFAULT_ABBREV;
-       }
-
-       oid_to_hex_r(hex, oid);
-       if (len == GIT_SHA1_HEXSZ || !len)
-               return GIT_SHA1_HEXSZ;
-
-       mad.init_len = len;
-       mad.cur_len = len;
-       mad.hex = hex;
-       mad.oid = oid;
-
-       find_abbrev_len_packed(&mad);
-
-       if (init_object_disambiguation(hex, mad.cur_len, &ds) < 0)
-               return -1;
-
-       ds.fn = extend_abbrev_len;
-       ds.always_call_fn = 1;
-       ds.cb_data = (void *)&mad;
-
-       find_short_object_filename(&ds);
-       (void)finish_object_disambiguation(&ds, &oid_ret);
-
-       hex[mad.cur_len] = 0;
-       return mad.cur_len;
-}
-
-const char *find_unique_abbrev(const struct object_id *oid, int len)
-{
-       static int bufno;
-       static char hexbuffer[4][GIT_MAX_HEXSZ + 1];
-       char *hex = hexbuffer[bufno];
-       bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
-       find_unique_abbrev_r(hex, oid, len);
-       return hex;
-}
-
-static int ambiguous_path(const char *path, int len)
-{
-       int slash = 1;
-       int cnt;
-
-       for (cnt = 0; cnt < len; cnt++) {
-               switch (*path++) {
-               case '\0':
-                       break;
-               case '/':
-                       if (slash)
-                               break;
-                       slash = 1;
-                       continue;
-               case '.':
-                       continue;
-               default:
-                       slash = 0;
-                       continue;
-               }
-               break;
-       }
-       return slash;
-}
-
-static inline int at_mark(const char *string, int len,
-                         const char **suffix, int nr)
-{
-       int i;
-
-       for (i = 0; i < nr; i++) {
-               int suffix_len = strlen(suffix[i]);
-               if (suffix_len <= len
-                   && !strncasecmp(string, suffix[i], suffix_len))
-                       return suffix_len;
-       }
-       return 0;
-}
-
-static inline int upstream_mark(const char *string, int len)
-{
-       const char *suffix[] = { "@{upstream}", "@{u}" };
-       return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
-}
-
-static inline int push_mark(const char *string, int len)
-{
-       const char *suffix[] = { "@{push}" };
-       return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
-}
-
-static int get_oid_1(const char *name, int len, struct object_id *oid, unsigned lookup_flags);
-static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
-
-static int get_oid_basic(const char *str, int len, struct object_id *oid,
-                         unsigned int flags)
-{
-       static const char *warn_msg = "refname '%.*s' is ambiguous.";
-       static const char *object_name_msg = N_(
-       "Git normally never creates a ref that ends with 40 hex characters\n"
-       "because it will be ignored when you just specify 40-hex. These refs\n"
-       "may be created by mistake. For example,\n"
-       "\n"
-       "  git checkout -b $br $(git rev-parse ...)\n"
-       "\n"
-       "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
-       "examine these refs and maybe delete them. Turn this message off by\n"
-       "running \"git config advice.objectNameWarning false\"");
-       struct object_id tmp_oid;
-       char *real_ref = NULL;
-       int refs_found = 0;
-       int at, reflog_len, nth_prior = 0;
-
-       if (len == GIT_SHA1_HEXSZ && !get_oid_hex(str, oid)) {
-               if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
-                       refs_found = dwim_ref(str, len, &tmp_oid, &real_ref);
-                       if (refs_found > 0) {
-                               warning(warn_msg, len, str);
-                               if (advice_object_name_warning)
-                                       fprintf(stderr, "%s\n", _(object_name_msg));
-                       }
-                       free(real_ref);
-               }
-               return 0;
-       }
-
-       /* basic@{time or number or -number} format to query ref-log */
-       reflog_len = at = 0;
-       if (len && str[len-1] == '}') {
-               for (at = len-4; at >= 0; at--) {
-                       if (str[at] == '@' && str[at+1] == '{') {
-                               if (str[at+2] == '-') {
-                                       if (at != 0)
-                                               /* @{-N} not at start */
-                                               return -1;
-                                       nth_prior = 1;
-                                       continue;
-                               }
-                               if (!upstream_mark(str + at, len - at) &&
-                                   !push_mark(str + at, len - at)) {
-                                       reflog_len = (len-1) - (at+2);
-                                       len = at;
-                               }
-                               break;
-                       }
-               }
-       }
-
-       /* Accept only unambiguous ref paths. */
-       if (len && ambiguous_path(str, len))
-               return -1;
-
-       if (nth_prior) {
-               struct strbuf buf = STRBUF_INIT;
-               int detached;
-
-               if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
-                       detached = (buf.len == GIT_SHA1_HEXSZ && !get_oid_hex(buf.buf, oid));
-                       strbuf_release(&buf);
-                       if (detached)
-                               return 0;
-               }
-       }
-
-       if (!len && reflog_len)
-               /* allow "@{...}" to mean the current branch reflog */
-               refs_found = dwim_ref("HEAD", 4, oid, &real_ref);
-       else if (reflog_len)
-               refs_found = dwim_log(str, len, oid, &real_ref);
-       else
-               refs_found = dwim_ref(str, len, oid, &real_ref);
-
-       if (!refs_found)
-               return -1;
-
-       if (warn_ambiguous_refs && !(flags & GET_OID_QUIETLY) &&
-           (refs_found > 1 ||
-            !get_short_oid(str, len, &tmp_oid, GET_OID_QUIETLY)))
-               warning(warn_msg, len, str);
-
-       if (reflog_len) {
-               int nth, i;
-               timestamp_t at_time;
-               timestamp_t co_time;
-               int co_tz, co_cnt;
-
-               /* Is it asking for N-th entry, or approxidate? */
-               for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
-                       char ch = str[at+2+i];
-                       if ('0' <= ch && ch <= '9')
-                               nth = nth * 10 + ch - '0';
-                       else
-                               nth = -1;
-               }
-               if (100000000 <= nth) {
-                       at_time = nth;
-                       nth = -1;
-               } else if (0 <= nth)
-                       at_time = 0;
-               else {
-                       int errors = 0;
-                       char *tmp = xstrndup(str + at + 2, reflog_len);
-                       at_time = approxidate_careful(tmp, &errors);
-                       free(tmp);
-                       if (errors) {
-                               free(real_ref);
-                               return -1;
-                       }
-               }
-               if (read_ref_at(real_ref, flags, at_time, nth, oid, NULL,
-                               &co_time, &co_tz, &co_cnt)) {
-                       if (!len) {
-                               if (starts_with(real_ref, "refs/heads/")) {
-                                       str = real_ref + 11;
-                                       len = strlen(real_ref + 11);
-                               } else {
-                                       /* detached HEAD */
-                                       str = "HEAD";
-                                       len = 4;
-                               }
-                       }
-                       if (at_time) {
-                               if (!(flags & GET_OID_QUIETLY)) {
-                                       warning("Log for '%.*s' only goes "
-                                               "back to %s.", len, str,
-                                               show_date(co_time, co_tz, DATE_MODE(RFC2822)));
-                               }
-                       } else {
-                               if (flags & GET_OID_QUIETLY) {
-                                       exit(128);
-                               }
-                               die("Log for '%.*s' only has %d entries.",
-                                   len, str, co_cnt);
-                       }
-               }
-       }
-
-       free(real_ref);
-       return 0;
-}
-
-static int get_parent(const char *name, int len,
-                     struct object_id *result, int idx)
-{
-       struct object_id oid;
-       int ret = get_oid_1(name, len, &oid, GET_OID_COMMITTISH);
-       struct commit *commit;
-       struct commit_list *p;
-
-       if (ret)
-               return ret;
-       commit = lookup_commit_reference(&oid);
-       if (parse_commit(commit))
-               return -1;
-       if (!idx) {
-               oidcpy(result, &commit->object.oid);
-               return 0;
-       }
-       p = commit->parents;
-       while (p) {
-               if (!--idx) {
-                       oidcpy(result, &p->item->object.oid);
-                       return 0;
-               }
-               p = p->next;
-       }
-       return -1;
-}
-
-static int get_nth_ancestor(const char *name, int len,
-                           struct object_id *result, int generation)
-{
-       struct object_id oid;
-       struct commit *commit;
-       int ret;
-
-       ret = get_oid_1(name, len, &oid, GET_OID_COMMITTISH);
-       if (ret)
-               return ret;
-       commit = lookup_commit_reference(&oid);
-       if (!commit)
-               return -1;
-
-       while (generation--) {
-               if (parse_commit(commit) || !commit->parents)
-                       return -1;
-               commit = commit->parents->item;
-       }
-       oidcpy(result, &commit->object.oid);
-       return 0;
-}
-
-struct object *peel_to_type(const char *name, int namelen,
-                           struct object *o, enum object_type expected_type)
-{
-       if (name && !namelen)
-               namelen = strlen(name);
-       while (1) {
-               if (!o || (!o->parsed && !parse_object(&o->oid)))
-                       return NULL;
-               if (expected_type == OBJ_ANY || o->type == expected_type)
-                       return o;
-               if (o->type == OBJ_TAG)
-                       o = ((struct tag*) o)->tagged;
-               else if (o->type == OBJ_COMMIT)
-                       o = &(((struct commit *) o)->tree->object);
-               else {
-                       if (name)
-                               error("%.*s: expected %s type, but the object "
-                                     "dereferences to %s type",
-                                     namelen, name, type_name(expected_type),
-                                     type_name(o->type));
-                       return NULL;
-               }
-       }
-}
-
-static int peel_onion(const char *name, int len, struct object_id *oid,
-                     unsigned lookup_flags)
-{
-       struct object_id outer;
-       const char *sp;
-       unsigned int expected_type = 0;
-       struct object *o;
-
-       /*
-        * "ref^{type}" dereferences ref repeatedly until you cannot
-        * dereference anymore, or you get an object of given type,
-        * whichever comes first.  "ref^{}" means just dereference
-        * tags until you get a non-tag.  "ref^0" is a shorthand for
-        * "ref^{commit}".  "commit^{tree}" could be used to find the
-        * top-level tree of the given commit.
-        */
-       if (len < 4 || name[len-1] != '}')
-               return -1;
-
-       for (sp = name + len - 1; name <= sp; sp--) {
-               int ch = *sp;
-               if (ch == '{' && name < sp && sp[-1] == '^')
-                       break;
-       }
-       if (sp <= name)
-               return -1;
-
-       sp++; /* beginning of type name, or closing brace for empty */
-       if (starts_with(sp, "commit}"))
-               expected_type = OBJ_COMMIT;
-       else if (starts_with(sp, "tag}"))
-               expected_type = OBJ_TAG;
-       else if (starts_with(sp, "tree}"))
-               expected_type = OBJ_TREE;
-       else if (starts_with(sp, "blob}"))
-               expected_type = OBJ_BLOB;
-       else if (starts_with(sp, "object}"))
-               expected_type = OBJ_ANY;
-       else if (sp[0] == '}')
-               expected_type = OBJ_NONE;
-       else if (sp[0] == '/')
-               expected_type = OBJ_COMMIT;
-       else
-               return -1;
-
-       lookup_flags &= ~GET_OID_DISAMBIGUATORS;
-       if (expected_type == OBJ_COMMIT)
-               lookup_flags |= GET_OID_COMMITTISH;
-       else if (expected_type == OBJ_TREE)
-               lookup_flags |= GET_OID_TREEISH;
-
-       if (get_oid_1(name, sp - name - 2, &outer, lookup_flags))
-               return -1;
-
-       o = parse_object(&outer);
-       if (!o)
-               return -1;
-       if (!expected_type) {
-               o = deref_tag(o, name, sp - name - 2);
-               if (!o || (!o->parsed && !parse_object(&o->oid)))
-                       return -1;
-               oidcpy(oid, &o->oid);
-               return 0;
-       }
-
-       /*
-        * At this point, the syntax look correct, so
-        * if we do not get the needed object, we should
-        * barf.
-        */
-       o = peel_to_type(name, len, o, expected_type);
-       if (!o)
-               return -1;
-
-       oidcpy(oid, &o->oid);
-       if (sp[0] == '/') {
-               /* "$commit^{/foo}" */
-               char *prefix;
-               int ret;
-               struct commit_list *list = NULL;
-
-               /*
-                * $commit^{/}. Some regex implementation may reject.
-                * We don't need regex anyway. '' pattern always matches.
-                */
-               if (sp[1] == '}')
-                       return 0;
-
-               prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
-               commit_list_insert((struct commit *)o, &list);
-               ret = get_oid_oneline(prefix, oid, list);
-               free(prefix);
-               return ret;
-       }
-       return 0;
-}
-
-static int get_describe_name(const char *name, int len, struct object_id *oid)
-{
-       const char *cp;
-       unsigned flags = GET_OID_QUIETLY | GET_OID_COMMIT;
-
-       for (cp = name + len - 1; name + 2 <= cp; cp--) {
-               char ch = *cp;
-               if (!isxdigit(ch)) {
-                       /* We must be looking at g in "SOMETHING-g"
-                        * for it to be describe output.
-                        */
-                       if (ch == 'g' && cp[-1] == '-') {
-                               cp++;
-                               len -= cp - name;
-                               return get_short_oid(cp, len, oid, flags);
-                       }
-               }
-       }
-       return -1;
-}
-
-static int get_oid_1(const char *name, int len, struct object_id *oid, unsigned lookup_flags)
-{
-       int ret, has_suffix;
-       const char *cp;
-
-       /*
-        * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
-        */
-       has_suffix = 0;
-       for (cp = name + len - 1; name <= cp; cp--) {
-               int ch = *cp;
-               if ('0' <= ch && ch <= '9')
-                       continue;
-               if (ch == '~' || ch == '^')
-                       has_suffix = ch;
-               break;
-       }
-
-       if (has_suffix) {
-               int num = 0;
-               int len1 = cp - name;
-               cp++;
-               while (cp < name + len)
-                       num = num * 10 + *cp++ - '0';
-               if (!num && len1 == len - 1)
-                       num = 1;
-               if (has_suffix == '^')
-                       return get_parent(name, len1, oid, num);
-               /* else if (has_suffix == '~') -- goes without saying */
-               return get_nth_ancestor(name, len1, oid, num);
-       }
-
-       ret = peel_onion(name, len, oid, lookup_flags);
-       if (!ret)
-               return 0;
-
-       ret = get_oid_basic(name, len, oid, lookup_flags);
-       if (!ret)
-               return 0;
-
-       /* It could be describe output that is "SOMETHING-gXXXX" */
-       ret = get_describe_name(name, len, oid);
-       if (!ret)
-               return 0;
-
-       return get_short_oid(name, len, oid, lookup_flags);
-}
-
-/*
- * This interprets names like ':/Initial revision of "git"' by searching
- * through history and returning the first commit whose message starts
- * the given regular expression.
- *
- * For negative-matching, prefix the pattern-part with '!-', like: ':/!-WIP'.
- *
- * For a literal '!' character at the beginning of a pattern, you have to repeat
- * that, like: ':/!!foo'
- *
- * For future extension, all other sequences beginning with ':/!' are reserved.
- */
-
-/* Remember to update object flag allocation in object.h */
-#define ONELINE_SEEN (1u<<20)
-
-static int handle_one_ref(const char *path, const struct object_id *oid,
-                         int flag, void *cb_data)
-{
-       struct commit_list **list = cb_data;
-       struct object *object = parse_object(oid);
-       if (!object)
-               return 0;
-       if (object->type == OBJ_TAG) {
-               object = deref_tag(object, path, strlen(path));
-               if (!object)
-                       return 0;
-       }
-       if (object->type != OBJ_COMMIT)
-               return 0;
-       commit_list_insert((struct commit *)object, list);
-       return 0;
-}
-
-static int get_oid_oneline(const char *prefix, struct object_id *oid,
-                           struct commit_list *list)
-{
-       struct commit_list *backup = NULL, *l;
-       int found = 0;
-       int negative = 0;
-       regex_t regex;
-
-       if (prefix[0] == '!') {
-               prefix++;
-
-               if (prefix[0] == '-') {
-                       prefix++;
-                       negative = 1;
-               } else if (prefix[0] != '!') {
-                       return -1;
-               }
-       }
-
-       if (regcomp(&regex, prefix, REG_EXTENDED))
-               return -1;
-
-       for (l = list; l; l = l->next) {
-               l->item->object.flags |= ONELINE_SEEN;
-               commit_list_insert(l->item, &backup);
-       }
-       while (list) {
-               const char *p, *buf;
-               struct commit *commit;
-               int matches;
-
-               commit = pop_most_recent_commit(&list, ONELINE_SEEN);
-               if (!parse_object(&commit->object.oid))
-                       continue;
-               buf = get_commit_buffer(commit, NULL);
-               p = strstr(buf, "\n\n");
-               matches = negative ^ (p && !regexec(&regex, p + 2, 0, NULL, 0));
-               unuse_commit_buffer(commit, buf);
-
-               if (matches) {
-                       oidcpy(oid, &commit->object.oid);
-                       found = 1;
-                       break;
-               }
-       }
-       regfree(&regex);
-       free_commit_list(list);
-       for (l = backup; l; l = l->next)
-               clear_commit_marks(l->item, ONELINE_SEEN);
-       free_commit_list(backup);
-       return found ? 0 : -1;
-}
-
-struct grab_nth_branch_switch_cbdata {
-       int remaining;
-       struct strbuf buf;
-};
-
-static int grab_nth_branch_switch(struct object_id *ooid, struct object_id *noid,
-                                 const char *email, timestamp_t timestamp, int tz,
-                                 const char *message, void *cb_data)
-{
-       struct grab_nth_branch_switch_cbdata *cb = cb_data;
-       const char *match = NULL, *target = NULL;
-       size_t len;
-
-       if (skip_prefix(message, "checkout: moving from ", &match))
-               target = strstr(match, " to ");
-
-       if (!match || !target)
-               return 0;
-       if (--(cb->remaining) == 0) {
-               len = target - match;
-               strbuf_reset(&cb->buf);
-               strbuf_add(&cb->buf, match, len);
-               return 1; /* we are done */
-       }
-       return 0;
-}
-
-/*
- * Parse @{-N} syntax, return the number of characters parsed
- * if successful; otherwise signal an error with negative value.
- */
-static int interpret_nth_prior_checkout(const char *name, int namelen,
-                                       struct strbuf *buf)
-{
-       long nth;
-       int retval;
-       struct grab_nth_branch_switch_cbdata cb;
-       const char *brace;
-       char *num_end;
-
-       if (namelen < 4)
-               return -1;
-       if (name[0] != '@' || name[1] != '{' || name[2] != '-')
-               return -1;
-       brace = memchr(name, '}', namelen);
-       if (!brace)
-               return -1;
-       nth = strtol(name + 3, &num_end, 10);
-       if (num_end != brace)
-               return -1;
-       if (nth <= 0)
-               return -1;
-       cb.remaining = nth;
-       strbuf_init(&cb.buf, 20);
-
-       retval = 0;
-       if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
-               strbuf_reset(buf);
-               strbuf_addbuf(buf, &cb.buf);
-               retval = brace - name + 1;
-       }
-
-       strbuf_release(&cb.buf);
-       return retval;
-}
-
-int get_oid_mb(const char *name, struct object_id *oid)
-{
-       struct commit *one, *two;
-       struct commit_list *mbs;
-       struct object_id oid_tmp;
-       const char *dots;
-       int st;
-
-       dots = strstr(name, "...");
-       if (!dots)
-               return get_oid(name, oid);
-       if (dots == name)
-               st = get_oid("HEAD", &oid_tmp);
-       else {
-               struct strbuf sb;
-               strbuf_init(&sb, dots - name);
-               strbuf_add(&sb, name, dots - name);
-               st = get_oid_committish(sb.buf, &oid_tmp);
-               strbuf_release(&sb);
-       }
-       if (st)
-               return st;
-       one = lookup_commit_reference_gently(&oid_tmp, 0);
-       if (!one)
-               return -1;
-
-       if (get_oid_committish(dots[3] ? (dots + 3) : "HEAD", &oid_tmp))
-               return -1;
-       two = lookup_commit_reference_gently(&oid_tmp, 0);
-       if (!two)
-               return -1;
-       mbs = get_merge_bases(one, two);
-       if (!mbs || mbs->next)
-               st = -1;
-       else {
-               st = 0;
-               oidcpy(oid, &mbs->item->object.oid);
-       }
-       free_commit_list(mbs);
-       return st;
-}
-
-/* parse @something syntax, when 'something' is not {.*} */
-static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
-{
-       const char *next;
-
-       if (len || name[1] == '{')
-               return -1;
-
-       /* make sure it's a single @, or @@{.*}, not @foo */
-       next = memchr(name + len + 1, '@', namelen - len - 1);
-       if (next && next[1] != '{')
-               return -1;
-       if (!next)
-               next = name + namelen;
-       if (next != name + 1)
-               return -1;
-
-       strbuf_reset(buf);
-       strbuf_add(buf, "HEAD", 4);
-       return 1;
-}
-
-static int reinterpret(const char *name, int namelen, int len,
-                      struct strbuf *buf, unsigned allowed)
-{
-       /* we have extra data, which might need further processing */
-       struct strbuf tmp = STRBUF_INIT;
-       int used = buf->len;
-       int ret;
-
-       strbuf_add(buf, name + len, namelen - len);
-       ret = interpret_branch_name(buf->buf, buf->len, &tmp, allowed);
-       /* that data was not interpreted, remove our cruft */
-       if (ret < 0) {
-               strbuf_setlen(buf, used);
-               return len;
-       }
-       strbuf_reset(buf);
-       strbuf_addbuf(buf, &tmp);
-       strbuf_release(&tmp);
-       /* tweak for size of {-N} versus expanded ref name */
-       return ret - used + len;
-}
-
-static void set_shortened_ref(struct strbuf *buf, const char *ref)
-{
-       char *s = shorten_unambiguous_ref(ref, 0);
-       strbuf_reset(buf);
-       strbuf_addstr(buf, s);
-       free(s);
-}
-
-static int branch_interpret_allowed(const char *refname, unsigned allowed)
-{
-       if (!allowed)
-               return 1;
-
-       if ((allowed & INTERPRET_BRANCH_LOCAL) &&
-           starts_with(refname, "refs/heads/"))
-               return 1;
-       if ((allowed & INTERPRET_BRANCH_REMOTE) &&
-           starts_with(refname, "refs/remotes/"))
-               return 1;
-
-       return 0;
-}
-
-static int interpret_branch_mark(const char *name, int namelen,
-                                int at, struct strbuf *buf,
-                                int (*get_mark)(const char *, int),
-                                const char *(*get_data)(struct branch *,
-                                                        struct strbuf *),
-                                unsigned allowed)
-{
-       int len;
-       struct branch *branch;
-       struct strbuf err = STRBUF_INIT;
-       const char *value;
-
-       len = get_mark(name + at, namelen - at);
-       if (!len)
-               return -1;
-
-       if (memchr(name, ':', at))
-               return -1;
-
-       if (at) {
-               char *name_str = xmemdupz(name, at);
-               branch = branch_get(name_str);
-               free(name_str);
-       } else
-               branch = branch_get(NULL);
-
-       value = get_data(branch, &err);
-       if (!value)
-               die("%s", err.buf);
-
-       if (!branch_interpret_allowed(value, allowed))
-               return -1;
-
-       set_shortened_ref(buf, value);
-       return len + at;
-}
-
-int interpret_branch_name(const char *name, int namelen, struct strbuf *buf,
-                         unsigned allowed)
-{
-       char *at;
-       const char *start;
-       int len;
-
-       if (!namelen)
-               namelen = strlen(name);
-
-       if (!allowed || (allowed & INTERPRET_BRANCH_LOCAL)) {
-               len = interpret_nth_prior_checkout(name, namelen, buf);
-               if (!len) {
-                       return len; /* syntax Ok, not enough switches */
-               } else if (len > 0) {
-                       if (len == namelen)
-                               return len; /* consumed all */
-                       else
-                               return reinterpret(name, namelen, len, buf, allowed);
-               }
-       }
-
-       for (start = name;
-            (at = memchr(start, '@', namelen - (start - name)));
-            start = at + 1) {
-
-               if (!allowed || (allowed & INTERPRET_BRANCH_HEAD)) {
-                       len = interpret_empty_at(name, namelen, at - name, buf);
-                       if (len > 0)
-                               return reinterpret(name, namelen, len, buf,
-                                                  allowed);
-               }
-
-               len = interpret_branch_mark(name, namelen, at - name, buf,
-                                           upstream_mark, branch_get_upstream,
-                                           allowed);
-               if (len > 0)
-                       return len;
-
-               len = interpret_branch_mark(name, namelen, at - name, buf,
-                                           push_mark, branch_get_push,
-                                           allowed);
-               if (len > 0)
-                       return len;
-       }
-
-       return -1;
-}
-
-void strbuf_branchname(struct strbuf *sb, const char *name, unsigned allowed)
-{
-       int len = strlen(name);
-       int used = interpret_branch_name(name, len, sb, allowed);
-
-       if (used < 0)
-               used = 0;
-       strbuf_add(sb, name + used, len - used);
-}
-
-int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
-{
-       if (startup_info->have_repository)
-               strbuf_branchname(sb, name, INTERPRET_BRANCH_LOCAL);
-       else
-               strbuf_addstr(sb, name);
-
-       /*
-        * This splice must be done even if we end up rejecting the
-        * name; builtin/branch.c::copy_or_rename_branch() still wants
-        * to see what the name expanded to so that "branch -m" can be
-        * used as a tool to correct earlier mistakes.
-        */
-       strbuf_splice(sb, 0, 0, "refs/heads/", 11);
-
-       if (*name == '-' ||
-           !strcmp(sb->buf, "refs/heads/HEAD"))
-               return -1;
-
-       return check_refname_format(sb->buf, 0);
-}
-
-/*
- * This is like "get_oid_basic()", except it allows "object ID expressions",
- * notably "xyz^" for "parent of xyz"
- */
-int get_oid(const char *name, struct object_id *oid)
-{
-       struct object_context unused;
-       return get_oid_with_context(name, 0, oid, &unused);
-}
-
-
-/*
- * Many callers know that the user meant to name a commit-ish by
- * syntactical positions where the object name appears.  Calling this
- * function allows the machinery to disambiguate shorter-than-unique
- * abbreviated object names between commit-ish and others.
- *
- * Note that this does NOT error out when the named object is not a
- * commit-ish. It is merely to give a hint to the disambiguation
- * machinery.
- */
-int get_oid_committish(const char *name, struct object_id *oid)
-{
-       struct object_context unused;
-       return get_oid_with_context(name, GET_OID_COMMITTISH,
-                                   oid, &unused);
-}
-
-int get_oid_treeish(const char *name, struct object_id *oid)
-{
-       struct object_context unused;
-       return get_oid_with_context(name, GET_OID_TREEISH,
-                                   oid, &unused);
-}
-
-int get_oid_commit(const char *name, struct object_id *oid)
-{
-       struct object_context unused;
-       return get_oid_with_context(name, GET_OID_COMMIT,
-                                   oid, &unused);
-}
-
-int get_oid_tree(const char *name, struct object_id *oid)
-{
-       struct object_context unused;
-       return get_oid_with_context(name, GET_OID_TREE,
-                                   oid, &unused);
-}
-
-int get_oid_blob(const char *name, struct object_id *oid)
-{
-       struct object_context unused;
-       return get_oid_with_context(name, GET_OID_BLOB,
-                                   oid, &unused);
-}
-
-/* Must be called only when object_name:filename doesn't exist. */
-static void diagnose_invalid_oid_path(const char *prefix,
-                                     const char *filename,
-                                     const struct object_id *tree_oid,
-                                     const char *object_name,
-                                     int object_name_len)
-{
-       struct object_id oid;
-       unsigned mode;
-
-       if (!prefix)
-               prefix = "";
-
-       if (file_exists(filename))
-               die("Path '%s' exists on disk, but not in '%.*s'.",
-                   filename, object_name_len, object_name);
-       if (is_missing_file_error(errno)) {
-               char *fullname = xstrfmt("%s%s", prefix, filename);
-
-               if (!get_tree_entry(tree_oid, fullname, &oid, &mode)) {
-                       die("Path '%s' exists, but not '%s'.\n"
-                           "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
-                           fullname,
-                           filename,
-                           object_name_len, object_name,
-                           fullname,
-                           object_name_len, object_name,
-                           filename);
-               }
-               die("Path '%s' does not exist in '%.*s'",
-                   filename, object_name_len, object_name);
-       }
-}
-
-/* Must be called only when :stage:filename doesn't exist. */
-static void diagnose_invalid_index_path(int stage,
-                                       const char *prefix,
-                                       const char *filename)
-{
-       const struct cache_entry *ce;
-       int pos;
-       unsigned namelen = strlen(filename);
-       struct strbuf fullname = STRBUF_INIT;
-
-       if (!prefix)
-               prefix = "";
-
-       /* Wrong stage number? */
-       pos = cache_name_pos(filename, namelen);
-       if (pos < 0)
-               pos = -pos - 1;
-       if (pos < active_nr) {
-               ce = active_cache[pos];
-               if (ce_namelen(ce) == namelen &&
-                   !memcmp(ce->name, filename, namelen))
-                       die("Path '%s' is in the index, but not at stage %d.\n"
-                           "Did you mean ':%d:%s'?",
-                           filename, stage,
-                           ce_stage(ce), filename);
-       }
-
-       /* Confusion between relative and absolute filenames? */
-       strbuf_addstr(&fullname, prefix);
-       strbuf_addstr(&fullname, filename);
-       pos = cache_name_pos(fullname.buf, fullname.len);
-       if (pos < 0)
-               pos = -pos - 1;
-       if (pos < active_nr) {
-               ce = active_cache[pos];
-               if (ce_namelen(ce) == fullname.len &&
-                   !memcmp(ce->name, fullname.buf, fullname.len))
-                       die("Path '%s' is in the index, but not '%s'.\n"
-                           "Did you mean ':%d:%s' aka ':%d:./%s'?",
-                           fullname.buf, filename,
-                           ce_stage(ce), fullname.buf,
-                           ce_stage(ce), filename);
-       }
-
-       if (file_exists(filename))
-               die("Path '%s' exists on disk, but not in the index.", filename);
-       if (is_missing_file_error(errno))
-               die("Path '%s' does not exist (neither on disk nor in the index).",
-                   filename);
-
-       strbuf_release(&fullname);
-}
-
-
-static char *resolve_relative_path(const char *rel)
-{
-       if (!starts_with(rel, "./") && !starts_with(rel, "../"))
-               return NULL;
-
-       if (!is_inside_work_tree())
-               die("relative path syntax can't be used outside working tree.");
-
-       /* die() inside prefix_path() if resolved path is outside worktree */
-       return prefix_path(startup_info->prefix,
-                          startup_info->prefix ? strlen(startup_info->prefix) : 0,
-                          rel);
-}
-
-static int get_oid_with_context_1(const char *name,
-                                 unsigned flags,
-                                 const char *prefix,
-                                 struct object_id *oid,
-                                 struct object_context *oc)
-{
-       int ret, bracket_depth;
-       int namelen = strlen(name);
-       const char *cp;
-       int only_to_die = flags & GET_OID_ONLY_TO_DIE;
-
-       if (only_to_die)
-               flags |= GET_OID_QUIETLY;
-
-       memset(oc, 0, sizeof(*oc));
-       oc->mode = S_IFINVALID;
-       strbuf_init(&oc->symlink_path, 0);
-       ret = get_oid_1(name, namelen, oid, flags);
-       if (!ret)
-               return ret;
-       /*
-        * sha1:path --> object name of path in ent sha1
-        * :path -> object name of absolute path in index
-        * :./path -> object name of path relative to cwd in index
-        * :[0-3]:path -> object name of path in index at stage
-        * :/foo -> recent commit matching foo
-        */
-       if (name[0] == ':') {
-               int stage = 0;
-               const struct cache_entry *ce;
-               char *new_path = NULL;
-               int pos;
-               if (!only_to_die && namelen > 2 && name[1] == '/') {
-                       struct commit_list *list = NULL;
-
-                       for_each_ref(handle_one_ref, &list);
-                       commit_list_sort_by_date(&list);
-                       return get_oid_oneline(name + 2, oid, list);
-               }
-               if (namelen < 3 ||
-                   name[2] != ':' ||
-                   name[1] < '0' || '3' < name[1])
-                       cp = name + 1;
-               else {
-                       stage = name[1] - '0';
-                       cp = name + 3;
-               }
-               new_path = resolve_relative_path(cp);
-               if (!new_path) {
-                       namelen = namelen - (cp - name);
-               } else {
-                       cp = new_path;
-                       namelen = strlen(cp);
-               }
-
-               if (flags & GET_OID_RECORD_PATH)
-                       oc->path = xstrdup(cp);
-
-               if (!active_cache)
-                       read_cache();
-               pos = cache_name_pos(cp, namelen);
-               if (pos < 0)
-                       pos = -pos - 1;
-               while (pos < active_nr) {
-                       ce = active_cache[pos];
-                       if (ce_namelen(ce) != namelen ||
-                           memcmp(ce->name, cp, namelen))
-                               break;
-                       if (ce_stage(ce) == stage) {
-                               oidcpy(oid, &ce->oid);
-                               oc->mode = ce->ce_mode;
-                               free(new_path);
-                               return 0;
-                       }
-                       pos++;
-               }
-               if (only_to_die && name[1] && name[1] != '/')
-                       diagnose_invalid_index_path(stage, prefix, cp);
-               free(new_path);
-               return -1;
-       }
-       for (cp = name, bracket_depth = 0; *cp; cp++) {
-               if (*cp == '{')
-                       bracket_depth++;
-               else if (bracket_depth && *cp == '}')
-                       bracket_depth--;
-               else if (!bracket_depth && *cp == ':')
-                       break;
-       }
-       if (*cp == ':') {
-               struct object_id tree_oid;
-               int len = cp - name;
-               unsigned sub_flags = flags;
-
-               sub_flags &= ~GET_OID_DISAMBIGUATORS;
-               sub_flags |= GET_OID_TREEISH;
-
-               if (!get_oid_1(name, len, &tree_oid, sub_flags)) {
-                       const char *filename = cp+1;
-                       char *new_filename = NULL;
-
-                       new_filename = resolve_relative_path(filename);
-                       if (new_filename)
-                               filename = new_filename;
-                       if (flags & GET_OID_FOLLOW_SYMLINKS) {
-                               ret = get_tree_entry_follow_symlinks(tree_oid.hash,
-                                       filename, oid->hash, &oc->symlink_path,
-                                       &oc->mode);
-                       } else {
-                               ret = get_tree_entry(&tree_oid, filename, oid,
-                                                    &oc->mode);
-                               if (ret && only_to_die) {
-                                       diagnose_invalid_oid_path(prefix,
-                                                                  filename,
-                                                                  &tree_oid,
-                                                                  name, len);
-                               }
-                       }
-                       hashcpy(oc->tree, tree_oid.hash);
-                       if (flags & GET_OID_RECORD_PATH)
-                               oc->path = xstrdup(filename);
-
-                       free(new_filename);
-                       return ret;
-               } else {
-                       if (only_to_die)
-                               die("Invalid object name '%.*s'.", len, name);
-               }
-       }
-       return ret;
-}
-
-/*
- * Call this function when you know "name" given by the end user must
- * name an object but it doesn't; the function _may_ die with a better
- * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
- * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
- * you have a chance to diagnose the error further.
- */
-void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
-{
-       struct object_context oc;
-       struct object_id oid;
-       get_oid_with_context_1(name, GET_OID_ONLY_TO_DIE, prefix, &oid, &oc);
-}
-
-int get_oid_with_context(const char *str, unsigned flags, struct object_id *oid, struct object_context *oc)
-{
-       if (flags & GET_OID_FOLLOW_SYMLINKS && flags & GET_OID_ONLY_TO_DIE)
-               die("BUG: incompatible flags for get_sha1_with_context");
-       return get_oid_with_context_1(str, flags, NULL, oid, oc);
-}