pack_refs(): split creation of packed refs and entry writing

Split pack_refs() into multiple passes:

* Iterate over loose refs.  For each one that can be turned into a
packed ref, create a corresponding entry in the packed refs cache.

* Write the packed refs to the packed-refs file.

This change isolates the mutation of the packed-refs file to a single
place.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/refs.c b/refs.c
index 1184b9995bd47f52f4cd93be1490b5d9853bc653..9f1a007e3b4d08e888f378cc667635d2cbf79ecc 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -2023,35 +2023,50 @@ struct ref_to_prune {
 
 struct pack_refs_cb_data {
        unsigned int flags;
 
 struct pack_refs_cb_data {
        unsigned int flags;

+       struct ref_dir *packed_refs;

        struct ref_to_prune *ref_to_prune;
        struct ref_to_prune *ref_to_prune;

-       int fd;

 };
 
 };
 

-static int pack_one_ref(struct ref_entry *entry, void *cb_data)
+/*
+ * An each_ref_entry_fn that is run over loose references only.  If
+ * the loose reference can be packed, add an entry in the packed ref
+ * cache.  If the reference should be pruned, also add it to
+ * ref_to_prune in the pack_refs_cb_data.
+ */
+static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)

 {
        struct pack_refs_cb_data *cb = cb_data;
        enum peel_status peel_status;
 {
        struct pack_refs_cb_data *cb = cb_data;
        enum peel_status peel_status;

+       struct ref_entry *packed_entry;

        int is_tag_ref = !prefixcmp(entry->name, "refs/tags/");
 
        int is_tag_ref = !prefixcmp(entry->name, "refs/tags/");
 

-       /* ALWAYS pack refs that were already packed or are tags */
-       if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref &&
-           !(entry->flag & REF_ISPACKED))
+       /* ALWAYS pack tags */
+       if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)

                return 0;
 
        /* Do not pack symbolic or broken refs: */
        if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
                return 0;
 
                return 0;
 
        /* Do not pack symbolic or broken refs: */
        if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
                return 0;
 

+       /* Add a packed ref cache entry equivalent to the loose entry. */

        peel_status = peel_entry(entry, 1);
        if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
                die("internal error peeling reference %s (%s)",
                    entry->name, sha1_to_hex(entry->u.value.sha1));
        peel_status = peel_entry(entry, 1);
        if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
                die("internal error peeling reference %s (%s)",
                    entry->name, sha1_to_hex(entry->u.value.sha1));

-       write_packed_entry(cb->fd, entry->name, entry->u.value.sha1,
-                          peel_status == PEEL_PEELED ?
-                          entry->u.value.peeled : NULL);
+       packed_entry = find_ref(cb->packed_refs, entry->name);
+       if (packed_entry) {
+               /* Overwrite existing packed entry with info from loose entry */
+               packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
+               hashcpy(packed_entry->u.value.sha1, entry->u.value.sha1);
+       } else {
+               packed_entry = create_ref_entry(entry->name, entry->u.value.sha1,
+                                               REF_ISPACKED | REF_KNOWS_PEELED, 0);
+               add_ref(cb->packed_refs, packed_entry);
+       }
+       hashcpy(packed_entry->u.value.peeled, entry->u.value.peeled);

 
 

-       /* If the ref was already packed, there is no need to prune it. */
-       if ((cb->flags & PACK_REFS_PRUNE) && !(entry->flag & REF_ISPACKED)) {
+       /* Schedule the loose reference for pruning if requested. */
+       if ((cb->flags & PACK_REFS_PRUNE)) {

                int namelen = strlen(entry->name) + 1;
                struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
                hashcpy(n->sha1, entry->u.value.sha1);
                int namelen = strlen(entry->name) + 1;
                struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
                hashcpy(n->sha1, entry->u.value.sha1);


@@ -2118,16 +2133,21 @@ static struct lock_file packlock;
 int pack_refs(unsigned int flags)
 {
        struct pack_refs_cb_data cbdata;
 int pack_refs(unsigned int flags)
 {
        struct pack_refs_cb_data cbdata;

+       int fd;

 
        memset(&cbdata, 0, sizeof(cbdata));
        cbdata.flags = flags;
 
 
        memset(&cbdata, 0, sizeof(cbdata));
        cbdata.flags = flags;
 

-       cbdata.fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"),
-                                             LOCK_DIE_ON_ERROR);
+       fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"),
+                                      LOCK_DIE_ON_ERROR);
+       cbdata.packed_refs = get_packed_refs(&ref_cache);

 
 

-       write_or_die(cbdata.fd, PACKED_REFS_HEADER, strlen(PACKED_REFS_HEADER));
+       do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
+                                pack_if_possible_fn, &cbdata);
+
+       write_or_die(fd, PACKED_REFS_HEADER, strlen(PACKED_REFS_HEADER));
+       do_for_each_entry_in_dir(cbdata.packed_refs, 0, write_packed_entry_fn, &fd);

 
 

-       do_for_each_entry(&ref_cache, "", pack_one_ref, &cbdata);

        if (commit_lock_file(&packlock) < 0)
                die_errno("unable to overwrite old ref-pack file");
        prune_refs(cbdata.ref_to_prune);
        if (commit_lock_file(&packlock) < 0)
                die_errno("unable to overwrite old ref-pack file");
        prune_refs(cbdata.ref_to_prune);