Merge branch 'jk/faster-name-conflicts'
[gitweb.git] / refs.c
diff --git a/refs.c b/refs.c
index a4445a15a64d3aae0140bf62fbc27329229c48a3..311a6b52b1a9b65c997357e2d1d80e0e4743b2ca 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -24,6 +24,11 @@ static unsigned char refname_disposition[256] = {
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
 };
 
+/*
+ * Used as a flag to ref_transaction_delete when a loose ref is being
+ * pruned.
+ */
+#define REF_ISPRUNING  0x0100
 /*
  * Try to read one refname component from the front of refname.
  * Return the length of the component found, or -1 if the component is
@@ -779,37 +784,32 @@ static void prime_ref_dir(struct ref_dir *dir)
                        prime_ref_dir(get_ref_dir(entry));
        }
 }
-/*
- * Return true iff refname1 and refname2 conflict with each other.
- * Two reference names conflict if one of them exactly matches the
- * leading components of the other; e.g., "foo/bar" conflicts with
- * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
- * "foo/barbados".
- */
-static int names_conflict(const char *refname1, const char *refname2)
+
+static int entry_matches(struct ref_entry *entry, const char *refname)
 {
-       for (; *refname1 && *refname1 == *refname2; refname1++, refname2++)
-               ;
-       return (*refname1 == '\0' && *refname2 == '/')
-               || (*refname1 == '/' && *refname2 == '\0');
+       return refname && !strcmp(entry->name, refname);
 }
 
-struct name_conflict_cb {
-       const char *refname;
-       const char *oldrefname;
-       const char *conflicting_refname;
+struct nonmatching_ref_data {
+       const char *skip;
+       struct ref_entry *found;
 };
 
-static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
+static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
 {
-       struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
-       if (data->oldrefname && !strcmp(data->oldrefname, entry->name))
+       struct nonmatching_ref_data *data = vdata;
+
+       if (entry_matches(entry, data->skip))
                return 0;
-       if (names_conflict(data->refname, entry->name)) {
-               data->conflicting_refname = entry->name;
-               return 1;
-       }
-       return 0;
+
+       data->found = entry;
+       return 1;
+}
+
+static void report_refname_conflict(struct ref_entry *entry,
+                                   const char *refname)
+{
+       error("'%s' exists; cannot create '%s'", entry->name, refname);
 }
 
 /*
@@ -818,21 +818,84 @@ static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
  * oldrefname is non-NULL, ignore potential conflicts with oldrefname
  * (e.g., because oldrefname is scheduled for deletion in the same
  * operation).
+ *
+ * Two reference names conflict if one of them exactly matches the
+ * leading components of the other; e.g., "foo/bar" conflicts with
+ * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
+ * "foo/barbados".
  */
 static int is_refname_available(const char *refname, const char *oldrefname,
                                struct ref_dir *dir)
 {
-       struct name_conflict_cb data;
-       data.refname = refname;
-       data.oldrefname = oldrefname;
-       data.conflicting_refname = NULL;
+       const char *slash;
+       size_t len;
+       int pos;
+       char *dirname;
 
-       sort_ref_dir(dir);
-       if (do_for_each_entry_in_dir(dir, 0, name_conflict_fn, &data)) {
-               error("'%s' exists; cannot create '%s'",
-                     data.conflicting_refname, refname);
+       for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
+               /*
+                * We are still at a leading dir of the refname; we are
+                * looking for a conflict with a leaf entry.
+                *
+                * If we find one, we still must make sure it is
+                * not "oldrefname".
+                */
+               pos = search_ref_dir(dir, refname, slash - refname);
+               if (pos >= 0) {
+                       struct ref_entry *entry = dir->entries[pos];
+                       if (entry_matches(entry, oldrefname))
+                               return 1;
+                       report_refname_conflict(entry, refname);
+                       return 0;
+               }
+
+
+               /*
+                * Otherwise, we can try to continue our search with
+                * the next component; if we come up empty, we know
+                * there is nothing under this whole prefix.
+                */
+               pos = search_ref_dir(dir, refname, slash + 1 - refname);
+               if (pos < 0)
+                       return 1;
+
+               dir = get_ref_dir(dir->entries[pos]);
+       }
+
+       /*
+        * We are at the leaf of our refname; we want to
+        * make sure there are no directories which match it.
+        */
+       len = strlen(refname);
+       dirname = xmallocz(len + 1);
+       sprintf(dirname, "%s/", refname);
+       pos = search_ref_dir(dir, dirname, len + 1);
+       free(dirname);
+
+       if (pos >= 0) {
+               /*
+                * We found a directory named "refname". It is a
+                * problem iff it contains any ref that is not
+                * "oldrefname".
+                */
+               struct ref_entry *entry = dir->entries[pos];
+               struct ref_dir *dir = get_ref_dir(entry);
+               struct nonmatching_ref_data data;
+
+               data.skip = oldrefname;
+               sort_ref_dir(dir);
+               if (!do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data))
+                       return 1;
+
+               report_refname_conflict(data.found, refname);
                return 0;
        }
+
+       /*
+        * There is no point in searching for another leaf
+        * node which matches it; such an entry would be the
+        * ref we are looking for, not a conflict.
+        */
        return 1;
 }
 
@@ -1162,7 +1225,7 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 
                if (de->d_name[0] == '.')
                        continue;
-               if (has_extension(de->d_name, ".lock"))
+               if (ends_with(de->d_name, ".lock"))
                        continue;
                strbuf_addstr(&refname, de->d_name);
                refdir = *refs->name
@@ -1542,9 +1605,8 @@ static enum peel_status peel_object(const unsigned char *name, unsigned char *sh
 
        if (o->type == OBJ_NONE) {
                int type = sha1_object_info(name, NULL);
-               if (type < 0)
+               if (type < 0 || !object_as_type(o, type, 0))
                        return PEEL_INVALID;
-               o->type = type;
        }
 
        if (o->type != OBJ_TAG)
@@ -2173,15 +2235,6 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
        return NULL;
 }
 
-static struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
-{
-       char refpath[PATH_MAX];
-       if (check_refname_format(refname, 0))
-               return NULL;
-       strcpy(refpath, mkpath("refs/%s", refname));
-       return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
-}
-
 struct ref_lock *lock_any_ref_for_update(const char *refname,
                                         const unsigned char *old_sha1,
                                         int flags, int *type_p)
@@ -2195,25 +2248,12 @@ struct ref_lock *lock_any_ref_for_update(const char *refname,
  * Write an entry to the packed-refs file for the specified refname.
  * If peeled is non-NULL, write it as the entry's peeled value.
  */
-static void write_packed_entry(int fd, char *refname, unsigned char *sha1,
+static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
                               unsigned char *peeled)
 {
-       char line[PATH_MAX + 100];
-       int len;
-
-       len = snprintf(line, sizeof(line), "%s %s\n",
-                      sha1_to_hex(sha1), refname);
-       /* this should not happen but just being defensive */
-       if (len > sizeof(line))
-               die("too long a refname '%s'", refname);
-       write_or_die(fd, line, len);
-
-       if (peeled) {
-               if (snprintf(line, sizeof(line), "^%s\n",
-                            sha1_to_hex(peeled)) != PEELED_LINE_LENGTH)
-                       die("internal error");
-               write_or_die(fd, line, PEELED_LINE_LENGTH);
-       }
+       fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
+       if (peeled)
+               fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
 }
 
 /*
@@ -2221,13 +2261,12 @@ static void write_packed_entry(int fd, char *refname, unsigned char *sha1,
  */
 static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
 {
-       int *fd = cb_data;
        enum peel_status peel_status = peel_entry(entry, 0);
 
        if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
                error("internal error: %s is not a valid packed reference!",
                      entry->name);
-       write_packed_entry(*fd, entry->name, entry->u.value.sha1,
+       write_packed_entry(cb_data, entry->name, entry->u.value.sha1,
                           peel_status == PEEL_PEELED ?
                           entry->u.value.peeled : NULL);
        return 0;
@@ -2263,15 +2302,22 @@ int commit_packed_refs(void)
                get_packed_ref_cache(&ref_cache);
        int error = 0;
        int save_errno = 0;
+       FILE *out;
 
        if (!packed_ref_cache->lock)
                die("internal error: packed-refs not locked");
-       write_or_die(packed_ref_cache->lock->fd,
-                    PACKED_REFS_HEADER, strlen(PACKED_REFS_HEADER));
 
+       out = fdopen(packed_ref_cache->lock->fd, "w");
+       if (!out)
+               die_errno("unable to fdopen packed-refs descriptor");
+
+       fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
        do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
-                                0, write_packed_entry_fn,
-                                &packed_ref_cache->lock->fd);
+                                0, write_packed_entry_fn, out);
+       if (fclose(out))
+               die_errno("write error");
+       packed_ref_cache->lock->fd = -1;
+
        if (commit_lock_file(packed_ref_cache->lock)) {
                save_errno = errno;
                error = -1;
@@ -2391,13 +2437,25 @@ static void try_remove_empty_parents(char *name)
 /* make sure nobody touched the ref, and unlink */
 static void prune_ref(struct ref_to_prune *r)
 {
-       struct ref_lock *lock = lock_ref_sha1(r->name + 5, r->sha1);
+       struct ref_transaction *transaction;
+       struct strbuf err = STRBUF_INIT;
 
-       if (lock) {
-               unlink_or_warn(git_path("%s", r->name));
-               unlock_ref(lock);
-               try_remove_empty_parents(r->name);
+       if (check_refname_format(r->name, 0))
+               return;
+
+       transaction = ref_transaction_begin(&err);
+       if (!transaction ||
+           ref_transaction_delete(transaction, r->name, r->sha1,
+                                  REF_ISPRUNING, 1, &err) ||
+           ref_transaction_commit(transaction, NULL, &err)) {
+               ref_transaction_free(transaction);
+               error("%s", err.buf);
+               strbuf_release(&err);
+               return;
        }
+       ref_transaction_free(transaction);
+       strbuf_release(&err);
+       try_remove_empty_parents(r->name);
 }
 
 static void prune_refs(struct ref_to_prune *r)
@@ -2540,11 +2598,6 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
        return ret;
 }
 
-static int repack_without_ref(const char *refname)
-{
-       return repack_without_refs(&refname, 1, NULL);
-}
-
 static int delete_ref_loose(struct ref_lock *lock, int flag)
 {
        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
@@ -2562,24 +2615,22 @@ static int delete_ref_loose(struct ref_lock *lock, int flag)
 
 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 {
-       struct ref_lock *lock;
-       int ret = 0, flag = 0;
+       struct ref_transaction *transaction;
+       struct strbuf err = STRBUF_INIT;
 
-       lock = lock_ref_sha1_basic(refname, sha1, delopt, &flag);
-       if (!lock)
+       transaction = ref_transaction_begin(&err);
+       if (!transaction ||
+           ref_transaction_delete(transaction, refname, sha1, delopt,
+                                  sha1 && !is_null_sha1(sha1), &err) ||
+           ref_transaction_commit(transaction, NULL, &err)) {
+               error("%s", err.buf);
+               ref_transaction_free(transaction);
+               strbuf_release(&err);
                return 1;
-       ret |= delete_ref_loose(lock, flag);
-
-       /* removing the loose one could have resurrected an earlier
-        * packed one.  Also, if it was not loose we need to repack
-        * without it.
-        */
-       ret |= repack_without_ref(lock->ref_name);
-
-       unlink_or_warn(git_path("logs/%s", lock->ref_name));
-       clear_loose_ref_cache(&ref_cache);
-       unlock_ref(lock);
-       return ret;
+       }
+       ref_transaction_free(transaction);
+       strbuf_release(&err);
+       return 0;
 }
 
 /*
@@ -2878,7 +2929,7 @@ static int log_ref_write(const char *refname, const unsigned char *old_sha1,
        return 0;
 }
 
-static int is_branch(const char *refname)
+int is_branch(const char *refname)
 {
        return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
 }
@@ -3301,7 +3352,7 @@ static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data
 
                if (de->d_name[0] == '.')
                        continue;
-               if (has_extension(de->d_name, ".lock"))
+               if (ends_with(de->d_name, ".lock"))
                        continue;
                strbuf_addstr(name, de->d_name);
                if (stat(git_path("logs/%s", name->buf), &st) < 0) {
@@ -3336,25 +3387,6 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
        return retval;
 }
 
-static int update_ref_write(const char *action, const char *refname,
-                           const unsigned char *sha1, struct ref_lock *lock,
-                           struct strbuf *err, enum action_on_err onerr)
-{
-       if (write_ref_sha1(lock, sha1, action) < 0) {
-               const char *str = "Cannot update the ref '%s'.";
-               if (err)
-                       strbuf_addf(err, str, refname);
-
-               switch (onerr) {
-               case UPDATE_REFS_MSG_ON_ERR: error(str, refname); break;
-               case UPDATE_REFS_DIE_ON_ERR: die(str, refname); break;
-               case UPDATE_REFS_QUIET_ON_ERR: break;
-               }
-               return 1;
-       }
-       return 0;
-}
-
 /**
  * Information needed for a single ref update.  Set new_sha1 to the
  * new value or to zero to delete the ref.  To check the old value
@@ -3605,14 +3637,15 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                struct ref_update *update = updates[i];
 
                if (!is_null_sha1(update->new_sha1)) {
-                       ret = update_ref_write(msg,
-                                              update->refname,
-                                              update->new_sha1,
-                                              update->lock, err,
-                                              UPDATE_REFS_QUIET_ON_ERR);
-                       update->lock = NULL; /* freed by update_ref_write */
-                       if (ret)
+                       ret = write_ref_sha1(update->lock, update->new_sha1,
+                                            msg);
+                       update->lock = NULL; /* freed by write_ref_sha1 */
+                       if (ret) {
+                               if (err)
+                                       strbuf_addf(err, "Cannot update the ref '%s'.",
+                                                   update->refname);
                                goto cleanup;
+                       }
                }
        }
 
@@ -3621,8 +3654,9 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                struct ref_update *update = updates[i];
 
                if (update->lock) {
-                       delnames[delnum++] = update->lock->ref_name;
                        ret |= delete_ref_loose(update->lock, update->type);
+                       if (!(update->flags & REF_ISPRUNING))
+                               delnames[delnum++] = update->lock->ref_name;
                }
        }