remote prune: optimize "dangling symref" check/warning

When 'git remote prune' was used to delete many refs in a repository
with many refs, a lot of time was spent checking for (now) dangling
symbolic refs pointing to the deleted ref, since warn_dangling_symref()
was once per deleted ref to check all other refs in the repository.

Avoid this using the new warn_dangling_symrefs() function which
makes one pass over all refs and checks for all the deleted refs in
one go, after they have all been deleted.

Signed-off-by: Jens Lindström <jl@opera.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/remote.c b/builtin/remote.c
index d33abe6598c737ddc176544c951ca7269db03b79..9b3e368983570be72a5c4b8476f69dc39522d192 100644 (file)
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -1313,6 +1313,7 @@ static int prune_remote(const char *remote, int dry_run)
 {
        int result = 0, i;
        struct ref_states states;
+       struct string_list delete_refs_list = STRING_LIST_INIT_NODUP;
        const char **delete_refs;
        const char *dangling_msg = dry_run
                ? _(" %s will become dangling!")
@@ -1339,6 +1340,8 @@ static int prune_remote(const char *remote, int dry_run)
        for (i = 0; i < states.stale.nr; i++) {
                const char *refname = states.stale.items[i].util;
 
+               string_list_insert(&delete_refs_list, refname);
+
                if (!dry_run)
                        result |= delete_ref(refname, NULL, 0);
 
@@ -1348,9 +1351,11 @@ static int prune_remote(const char *remote, int dry_run)
                else
                        printf_ln(_(" * [pruned] %s"),
                               abbrev_ref(refname, "refs/remotes/"));
-               warn_dangling_symref(stdout, dangling_msg, refname);
        }
 
+       warn_dangling_symrefs(stdout, dangling_msg, &delete_refs_list);
+       string_list_clear(&delete_refs_list, 0);
+
        free_remote_ref_states(&states);
        return result;
 }

diff --git a/refs.c b/refs.c
index 262c1c26cb0d82f85f59e4a4dc513921be2080f0..59fb70087a438a763cdbfb2c4e75de36d533aead 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -1611,6 +1611,7 @@ int peel_ref(const char *refname, unsigned char *sha1)
 struct warn_if_dangling_data {
        FILE *fp;
        const char *refname;
+       const struct string_list *refnames;
        const char *msg_fmt;
 };
 
@@ -1625,8 +1626,12 @@ static int warn_if_dangling_symref(const char *refname, const unsigned char *sha
                return 0;
 
        resolves_to = resolve_ref_unsafe(refname, junk, 0, NULL);
-       if (!resolves_to || strcmp(resolves_to, d->refname))
+       if (!resolves_to
+           || (d->refname
+               ? strcmp(resolves_to, d->refname)
+               : !string_list_has_string(d->refnames, resolves_to))) {
                return 0;
+       }
 
        fprintf(d->fp, d->msg_fmt, refname);
        fputc('\n', d->fp);
@@ -1639,6 +1644,18 @@ void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 
        data.fp = fp;
        data.refname = refname;
+       data.refnames = NULL;
+       data.msg_fmt = msg_fmt;
+       for_each_rawref(warn_if_dangling_symref, &data);
+}
+
+void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
+{
+       struct warn_if_dangling_data data;
+
+       data.fp = fp;
+       data.refname = NULL;
+       data.refnames = refnames;
        data.msg_fmt = msg_fmt;
        for_each_rawref(warn_if_dangling_symref, &data);
 }

diff --git a/refs.h b/refs.h
index f287c7aa65cea7b0c52a7454fef14d6f4f1d4d38..1440acc06ce59f35d23719adef18774731efe5a4 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -89,6 +89,7 @@ static inline const char *has_glob_specials(const char *pattern)
 extern int for_each_rawref(each_ref_fn, void *);
 
 extern void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname);
+extern void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list* refnames);
 
 /*
  * Lock the packed-refs file for writing.  Flags is passed to