index-pack: Refactor base arguments of resolve_delta into a struct

We need to discard base objects which are not recently used if our
memory gets low, such as when we are unpacking a long delta chain
of a very large object.

To support tracking the available base objects we combine the
pointer and size into a struct.  Future changes would allow the
data pointer to be free'd and marked NULL if memory gets low.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Shawn O. Pearce 2008-07-13 22:07:44 -04:00 committed by Junio C Hamano
parent 191a8e32b3
commit f41aebd469

View File

@ -26,6 +26,11 @@ union delta_base {
off_t offset;
};
struct base_data {
void *data;
unsigned long size;
};
/*
* Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
* to memcmp() only the first 20 bytes.
@ -425,25 +430,25 @@ static void sha1_object(const void *data, unsigned long size,
}
}
static void resolve_delta(struct object_entry *delta_obj, void *base_data,
unsigned long base_size, enum object_type type)
static void resolve_delta(struct object_entry *delta_obj,
struct base_data *base_obj, enum object_type type)
{
void *delta_data;
unsigned long delta_size;
void *result;
unsigned long result_size;
union delta_base delta_base;
int j, first, last;
struct base_data result;
delta_obj->real_type = type;
delta_data = get_data_from_pack(delta_obj);
delta_size = delta_obj->size;
result = patch_delta(base_data, base_size, delta_data, delta_size,
&result_size);
result.data = patch_delta(base_obj->data, base_obj->size,
delta_data, delta_size,
&result.size);
free(delta_data);
if (!result)
if (!result.data)
bad_object(delta_obj->idx.offset, "failed to apply delta");
sha1_object(result, result_size, type, delta_obj->idx.sha1);
sha1_object(result.data, result.size, type, delta_obj->idx.sha1);
nr_resolved_deltas++;
hashcpy(delta_base.sha1, delta_obj->idx.sha1);
@ -451,7 +456,7 @@ static void resolve_delta(struct object_entry *delta_obj, void *base_data,
for (j = first; j <= last; j++) {
struct object_entry *child = objects + deltas[j].obj_no;
if (child->real_type == OBJ_REF_DELTA)
resolve_delta(child, result, result_size, type);
resolve_delta(child, &result, type);
}
}
@ -461,11 +466,11 @@ static void resolve_delta(struct object_entry *delta_obj, void *base_data,
for (j = first; j <= last; j++) {
struct object_entry *child = objects + deltas[j].obj_no;
if (child->real_type == OBJ_OFS_DELTA)
resolve_delta(child, result, result_size, type);
resolve_delta(child, &result, type);
}
}
free(result);
free(result.data);
}
static int compare_delta_entry(const void *a, const void *b)
@ -480,7 +485,6 @@ static void parse_pack_objects(unsigned char *sha1)
{
int i;
struct delta_entry *delta = deltas;
void *data;
struct stat st;
/*
@ -495,7 +499,7 @@ static void parse_pack_objects(unsigned char *sha1)
nr_objects);
for (i = 0; i < nr_objects; i++) {
struct object_entry *obj = &objects[i];
data = unpack_raw_entry(obj, &delta->base);
void *data = unpack_raw_entry(obj, &delta->base);
obj->real_type = obj->type;
if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
nr_deltas++;
@ -544,6 +548,7 @@ static void parse_pack_objects(unsigned char *sha1)
struct object_entry *obj = &objects[i];
union delta_base base;
int j, ref, ref_first, ref_last, ofs, ofs_first, ofs_last;
struct base_data base_obj;
if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
continue;
@ -554,22 +559,22 @@ static void parse_pack_objects(unsigned char *sha1)
ofs = !find_delta_children(&base, &ofs_first, &ofs_last);
if (!ref && !ofs)
continue;
data = get_data_from_pack(obj);
base_obj.data = get_data_from_pack(obj);
base_obj.size = obj->size;
if (ref)
for (j = ref_first; j <= ref_last; j++) {
struct object_entry *child = objects + deltas[j].obj_no;
if (child->real_type == OBJ_REF_DELTA)
resolve_delta(child, data,
obj->size, obj->type);
resolve_delta(child, &base_obj, obj->type);
}
if (ofs)
for (j = ofs_first; j <= ofs_last; j++) {
struct object_entry *child = objects + deltas[j].obj_no;
if (child->real_type == OBJ_OFS_DELTA)
resolve_delta(child, data,
obj->size, obj->type);
resolve_delta(child, &base_obj, obj->type);
}
free(data);
free(base_obj.data);
display_progress(progress, nr_resolved_deltas);
}
}
@ -655,28 +660,29 @@ static void fix_unresolved_deltas(int nr_unresolved)
for (i = 0; i < n; i++) {
struct delta_entry *d = sorted_by_pos[i];
void *data;
unsigned long size;
enum object_type type;
int j, first, last;
struct base_data base_obj;
if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
continue;
data = read_sha1_file(d->base.sha1, &type, &size);
if (!data)
base_obj.data = read_sha1_file(d->base.sha1, &type, &base_obj.size);
if (!base_obj.data)
continue;
find_delta_children(&d->base, &first, &last);
for (j = first; j <= last; j++) {
struct object_entry *child = objects + deltas[j].obj_no;
if (child->real_type == OBJ_REF_DELTA)
resolve_delta(child, data, size, type);
resolve_delta(child, &base_obj, type);
}
if (check_sha1_signature(d->base.sha1, data, size, typename(type)))
if (check_sha1_signature(d->base.sha1, base_obj.data,
base_obj.size, typename(type)))
die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
append_obj_to_pack(d->base.sha1, data, size, type);
free(data);
append_obj_to_pack(d->base.sha1, base_obj.data,
base_obj.size, type);
free(base_obj.data);
display_progress(progress, nr_resolved_deltas);
}
free(sorted_by_pos);