index-pack: calculate {ref,ofs}_{first,last} early
This is refactoring 2 of 2 to simplify struct base_data. Whenever we make a struct base_data, immediately calculate its delta children. This eliminates confusion as to when the {ref,ofs}_{first,last} fields are initialized. Before this patch, the delta children were calculated at the last possible moment. This allowed the members of struct base_data to be populated in any order, superficially useful when we have the object contents before the struct object_entry. But this makes reasoning about the state of struct base_data more complicated, hence this patch. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Jonathan Tan committed
Aug 24, 2020 at 12:16 UTC
b4718cae51f9630f2901c452ca4e4dfbf68f47ef
1 file changed
+60
-63
builtin/index-pack.c
+60
-63
@@ -33,12 +33,15 @@ struct object_stat {
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};
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struct base_data {
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+ /* Initialized by make_base(). */
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struct base_data *base;
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struct object_entry *obj;
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- void *data;
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- unsigned long size;
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int ref_first, ref_last;
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int ofs_first, ofs_last;
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+
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+ /* Not initialized by make_base(). */
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+ void *data;
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+ unsigned long size;
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};
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struct thread_local {
@@ -362,14 +365,6 @@ static void set_thread_data(struct thread_local *data)
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pthread_setspecific(key, data);
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}
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-static struct base_data *alloc_base_data(void)
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-{
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- struct base_data *base = xcalloc(1, sizeof(struct base_data));
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- base->ref_last = -1;
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- base->ofs_last = -1;
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- return base;
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-}
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-
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static void free_base_data(struct base_data *c)
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{
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if (c->data) {
@@ -406,19 +401,6 @@ static void prune_base_data(struct base_data *youngest_child)
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free(ancestry);
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}
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-static void link_base_data(struct base_data *base, struct base_data *c)
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-{
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- c->base = base;
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- if (c->data)
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- get_thread_data()->base_cache_used += c->size;
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- prune_base_data(c);
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-}
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-
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-static void unlink_base_data(struct base_data *c)
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-{
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- free_base_data(c);
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-}
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-
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static int is_delta_type(enum object_type type)
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{
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return (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA);
@@ -929,10 +911,25 @@ static void *get_base_data(struct base_data *c)
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return c->data;
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}
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-static void resolve_delta(struct object_entry *delta_obj,
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- struct base_data *base, struct base_data *result)
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+static struct base_data *make_base(struct object_entry *obj,
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+ struct base_data *parent)
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{
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- void *base_data, *delta_data;
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+ struct base_data *base = xcalloc(1, sizeof(struct base_data));
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+ base->base = parent;
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+ base->obj = obj;
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+ find_ref_delta_children(&obj->idx.oid,
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+ &base->ref_first, &base->ref_last);
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+ find_ofs_delta_children(obj->idx.offset,
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+ &base->ofs_first, &base->ofs_last);
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+ return base;
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+}
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+
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+static struct base_data *resolve_delta(struct object_entry *delta_obj,
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+ struct base_data *base)
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+{
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+ void *base_data, *delta_data, *result_data;
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+ struct base_data *result;
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+ unsigned long result_size;
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if (show_stat) {
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int i = delta_obj - objects;
@@ -946,19 +943,31 @@ static void resolve_delta(struct object_entry *delta_obj,
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}
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delta_data = get_data_from_pack(delta_obj);
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base_data = get_base_data(base);
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- result->obj = delta_obj;
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- result->data = patch_delta(base_data, base->size,
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- delta_data, delta_obj->size, &result->size);
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+ result_data = patch_delta(base_data, base->size,
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+ delta_data, delta_obj->size, &result_size);
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free(delta_data);
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- if (!result->data)
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+ if (!result_data)
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bad_object(delta_obj->idx.offset, _("failed to apply delta"));
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- hash_object_file(the_hash_algo, result->data, result->size,
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+ hash_object_file(the_hash_algo, result_data, result_size,
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type_name(delta_obj->real_type), &delta_obj->idx.oid);
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- sha1_object(result->data, NULL, result->size, delta_obj->real_type,
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+ sha1_object(result_data, NULL, result_size, delta_obj->real_type,
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&delta_obj->idx.oid);
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+
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+ result = make_base(delta_obj, base);
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+ if (result->ref_last == -1 && result->ofs_last == -1) {
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+ free(result_data);
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+ } else {
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+ result->data = result_data;
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+ result->size = result_size;
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+ get_thread_data()->base_cache_used += result->size;
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+ prune_base_data(result);
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+ }
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+
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counter_lock();
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nr_resolved_deltas++;
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counter_unlock();
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+
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+ return result;
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}
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/*
@@ -984,24 +993,9 @@ static int compare_and_swap_type(signed char *type,
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static struct base_data *find_unresolved_deltas_1(struct base_data *base,
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struct base_data *prev_base)
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{
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- if (base->ref_last == -1 && base->ofs_last == -1) {
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- find_ref_delta_children(&base->obj->idx.oid,
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- &base->ref_first, &base->ref_last);
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-
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- find_ofs_delta_children(base->obj->idx.offset,
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- &base->ofs_first, &base->ofs_last);
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-
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- if (base->ref_last == -1 && base->ofs_last == -1) {
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- free(base->data);
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- return NULL;
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- }
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-
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- link_base_data(prev_base, base);
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- }
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-
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if (base->ref_first <= base->ref_last) {
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struct object_entry *child = objects + ref_deltas[base->ref_first].obj_no;
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- struct base_data *result = alloc_base_data();
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+ struct base_data *result;
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if (!compare_and_swap_type(&child->real_type, OBJ_REF_DELTA,
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base->obj->real_type))
@@ -1009,7 +1003,7 @@ static struct base_data *find_unresolved_deltas_1(struct base_data *base,
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(uintmax_t)child->idx.offset,
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oid_to_hex(&base->obj->idx.oid));
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- resolve_delta(child, base, result);
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+ result = resolve_delta(child, base);
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if (base->ref_first == base->ref_last && base->ofs_last == -1)
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free_base_data(base);
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@@ -1019,11 +1013,11 @@ static struct base_data *find_unresolved_deltas_1(struct base_data *base,
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if (base->ofs_first <= base->ofs_last) {
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struct object_entry *child = objects + ofs_deltas[base->ofs_first].obj_no;
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- struct base_data *result = alloc_base_data();
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+ struct base_data *result;
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assert(child->real_type == OBJ_OFS_DELTA);
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child->real_type = base->obj->real_type;
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- resolve_delta(child, base, result);
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+ result = resolve_delta(child, base);
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if (base->ofs_first == base->ofs_last)
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free_base_data(base);
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@@ -1031,7 +1025,7 @@ static struct base_data *find_unresolved_deltas_1(struct base_data *base,
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return result;
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}
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- unlink_base_data(base);
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+ free_base_data(base);
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return NULL;
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}
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@@ -1074,9 +1068,8 @@ static int compare_ref_delta_entry(const void *a, const void *b)
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static void resolve_base(struct object_entry *obj)
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{
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- struct base_data *base_obj = alloc_base_data();
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- base_obj->obj = obj;
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- base_obj->data = NULL;
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+ struct base_data *base_obj = make_base(obj, NULL);
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+
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find_unresolved_deltas(base_obj);
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}
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@@ -1369,22 +1362,26 @@ static void fix_unresolved_deltas(struct hashfile *f)
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for (i = 0; i < nr_ref_deltas; i++) {
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struct ref_delta_entry *d = sorted_by_pos[i];
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enum object_type type;
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- struct base_data *base_obj = alloc_base_data();
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+ struct base_data *base;
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+ void *data;
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+ unsigned long size;
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+ struct object_entry *obj;
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if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
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continue;
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- base_obj->data = read_object_file(&d->oid, &type,
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- &base_obj->size);
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- if (!base_obj->data)
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+ data = read_object_file(&d->oid, &type, &size);
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+ if (!data)
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continue;
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if (check_object_signature(the_repository, &d->oid,
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- base_obj->data, base_obj->size,
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+ data, size,
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type_name(type)))
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die(_("local object %s is corrupt"), oid_to_hex(&d->oid));
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- base_obj->obj = append_obj_to_pack(f, d->oid.hash,
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- base_obj->data, base_obj->size, type);
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- find_unresolved_deltas(base_obj);
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+ obj = append_obj_to_pack(f, d->oid.hash, data, size, type);
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+ base = make_base(obj, NULL);
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+ base->data = data;
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+ base->size = size;
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+ find_unresolved_deltas(base);
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display_progress(progress, nr_resolved_deltas);
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}
1387
free(sorted_by_pos);