packfile: disentangle return value of `packed_object_info()`

The `packed_object_info()` function returns the type of the packed
object. While we use an `enum object_type` to store the return value,
this type is not to be confused with the actual object type. It _may_
contain the object type, but it may just as well encode that the given
packed object is stored as a delta.

We have removed the only caller that relied on this returned object type
in the preceding commit, so let's simplify semantics and return either 0
on success or a negative error code otherwise.

This unblocks a small optimization where we can skip reading the object
type altogether.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/packfile.c b/packfile.c
index f7c33a2f77a96695fdd6fd9ebad988f105eb2028..8c6ef45a6727bde726deb215d5cadea90f0755ba 100644 (file)
--- a/packfile.c
+++ b/packfile.c
@@ -1587,6 +1587,7 @@ int packed_object_info(struct repository *r, struct packed_git *p,
        unsigned long size;
        off_t curpos = obj_offset;
        enum object_type type;
+       int ret;
 
        /*
         * We always get the representation type, but only convert it to
@@ -1607,12 +1608,12 @@ int packed_object_info(struct repository *r, struct packed_git *p,
                        off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
                                                           type, obj_offset);
                        if (!base_offset) {
-                               type = OBJ_BAD;
+                               ret = -1;
                                goto out;
                        }
                        *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
                        if (*oi->sizep == 0) {
-                               type = OBJ_BAD;
+                               ret = -1;
                                goto out;
                        }
                } else {
@@ -1625,7 +1626,7 @@ int packed_object_info(struct repository *r, struct packed_git *p,
                if (offset_to_pack_pos(p, obj_offset, &pos) < 0) {
                        error("could not find object at offset %"PRIuMAX" "
                              "in pack %s", (uintmax_t)obj_offset, p->pack_name);
-                       type = OBJ_BAD;
+                       ret = -1;
                        goto out;
                }
 
@@ -1639,7 +1640,7 @@ int packed_object_info(struct repository *r, struct packed_git *p,
                if (oi->typep)
                        *oi->typep = ptot;
                if (ptot < 0) {
-                       type = OBJ_BAD;
+                       ret = -1;
                        goto out;
                }
        }
@@ -1649,7 +1650,7 @@ int packed_object_info(struct repository *r, struct packed_git *p,
                        if (get_delta_base_oid(p, &w_curs, curpos,
                                               oi->delta_base_oid,
                                               type, obj_offset) < 0) {
-                               type = OBJ_BAD;
+                               ret = -1;
                                goto out;
                        }
                } else
@@ -1672,9 +1673,11 @@ int packed_object_info(struct repository *r, struct packed_git *p,
                break;
        }
 
+       ret = 0;
+
 out:
        unuse_pack(&w_curs);
-       return type;
+       return ret;
 }
 
 static void *unpack_compressed_entry(struct packed_git *p,
@@ -2152,7 +2155,7 @@ int packfile_store_read_object_info(struct packfile_store *store,
                                    unsigned flags UNUSED)
 {
        struct pack_entry e;
-       int rtype;
+       int ret;
 
        if (!find_pack_entry(store->odb->repo, oid, &e))
                return 1;
@@ -2164,8 +2167,8 @@ int packfile_store_read_object_info(struct packfile_store *store,
        if (!oi)
                return 0;
 
-       rtype = packed_object_info(store->odb->repo, e.p, e.offset, oi);
-       if (rtype < 0) {
+       ret = packed_object_info(store->odb->repo, e.p, e.offset, oi);
+       if (ret < 0) {
                mark_bad_packed_object(e.p, oid);
                return -1;
        }

diff --git a/packfile.h b/packfile.h
index 59d162a3f415e50d05af84a77beed7fedbbb6fc2..07f5bfbc4fc63126fbfaa73417640de070043275 100644 (file)
--- a/packfile.h
+++ b/packfile.h
@@ -378,6 +378,10 @@ void release_pack_memory(size_t);
 /* global flag to enable extra checks when accessing packed objects */
 extern int do_check_packed_object_crc;
 
+/*
+ * Look up the object info for a specific offset in the packfile.
+ * success, a negative error code otherwise.
+ */
 int packed_object_info(struct repository *r,
                       struct packed_git *pack,
                       off_t offset, struct object_info *);