git/pack-bitmap.c
James Clarke da41c942b3 pack-bitmap: don't perform unaligned memory access
The preceding bitmap entries have a 1-byte XOR-offset and 1-byte flags,
so their size is not a multiple of 4. Thus the name-hash cache is only
guaranteed to be 2-byte aligned and so we must use get_be32 rather than
indexing the array directly.

Signed-off-by: James Clarke <jrtc27@jrtc27.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-26 12:32:31 -07:00

1069 lines
25 KiB
C

#include "cache.h"
#include "commit.h"
#include "tag.h"
#include "diff.h"
#include "revision.h"
#include "progress.h"
#include "list-objects.h"
#include "pack.h"
#include "pack-bitmap.h"
#include "pack-revindex.h"
#include "pack-objects.h"
/*
* An entry on the bitmap index, representing the bitmap for a given
* commit.
*/
struct stored_bitmap {
unsigned char sha1[20];
struct ewah_bitmap *root;
struct stored_bitmap *xor;
int flags;
};
/*
* The currently active bitmap index. By design, repositories only have
* a single bitmap index available (the index for the biggest packfile in
* the repository), since bitmap indexes need full closure.
*
* If there is more than one bitmap index available (e.g. because of alternates),
* the active bitmap index is the largest one.
*/
static struct bitmap_index {
/* Packfile to which this bitmap index belongs to */
struct packed_git *pack;
/*
* Mark the first `reuse_objects` in the packfile as reused:
* they will be sent as-is without using them for repacking
* calculations
*/
uint32_t reuse_objects;
/* mmapped buffer of the whole bitmap index */
unsigned char *map;
size_t map_size; /* size of the mmaped buffer */
size_t map_pos; /* current position when loading the index */
/*
* Type indexes.
*
* Each bitmap marks which objects in the packfile are of the given
* type. This provides type information when yielding the objects from
* the packfile during a walk, which allows for better delta bases.
*/
struct ewah_bitmap *commits;
struct ewah_bitmap *trees;
struct ewah_bitmap *blobs;
struct ewah_bitmap *tags;
/* Map from SHA1 -> `stored_bitmap` for all the bitmapped commits */
khash_sha1 *bitmaps;
/* Number of bitmapped commits */
uint32_t entry_count;
/* Name-hash cache (or NULL if not present). */
uint32_t *hashes;
/*
* Extended index.
*
* When trying to perform bitmap operations with objects that are not
* packed in `pack`, these objects are added to this "fake index" and
* are assumed to appear at the end of the packfile for all operations
*/
struct eindex {
struct object **objects;
uint32_t *hashes;
uint32_t count, alloc;
khash_sha1_pos *positions;
} ext_index;
/* Bitmap result of the last performed walk */
struct bitmap *result;
/* Version of the bitmap index */
unsigned int version;
unsigned loaded : 1;
} bitmap_git;
static struct ewah_bitmap *lookup_stored_bitmap(struct stored_bitmap *st)
{
struct ewah_bitmap *parent;
struct ewah_bitmap *composed;
if (st->xor == NULL)
return st->root;
composed = ewah_pool_new();
parent = lookup_stored_bitmap(st->xor);
ewah_xor(st->root, parent, composed);
ewah_pool_free(st->root);
st->root = composed;
st->xor = NULL;
return composed;
}
/*
* Read a bitmap from the current read position on the mmaped
* index, and increase the read position accordingly
*/
static struct ewah_bitmap *read_bitmap_1(struct bitmap_index *index)
{
struct ewah_bitmap *b = ewah_pool_new();
int bitmap_size = ewah_read_mmap(b,
index->map + index->map_pos,
index->map_size - index->map_pos);
if (bitmap_size < 0) {
error("Failed to load bitmap index (corrupted?)");
ewah_pool_free(b);
return NULL;
}
index->map_pos += bitmap_size;
return b;
}
static int load_bitmap_header(struct bitmap_index *index)
{
struct bitmap_disk_header *header = (void *)index->map;
if (index->map_size < sizeof(*header) + 20)
return error("Corrupted bitmap index (missing header data)");
if (memcmp(header->magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE)) != 0)
return error("Corrupted bitmap index file (wrong header)");
index->version = ntohs(header->version);
if (index->version != 1)
return error("Unsupported version for bitmap index file (%d)", index->version);
/* Parse known bitmap format options */
{
uint32_t flags = ntohs(header->options);
if ((flags & BITMAP_OPT_FULL_DAG) == 0)
return error("Unsupported options for bitmap index file "
"(Git requires BITMAP_OPT_FULL_DAG)");
if (flags & BITMAP_OPT_HASH_CACHE) {
unsigned char *end = index->map + index->map_size - 20;
index->hashes = ((uint32_t *)end) - index->pack->num_objects;
}
}
index->entry_count = ntohl(header->entry_count);
index->map_pos += sizeof(*header);
return 0;
}
static struct stored_bitmap *store_bitmap(struct bitmap_index *index,
struct ewah_bitmap *root,
const unsigned char *sha1,
struct stored_bitmap *xor_with,
int flags)
{
struct stored_bitmap *stored;
khiter_t hash_pos;
int ret;
stored = xmalloc(sizeof(struct stored_bitmap));
stored->root = root;
stored->xor = xor_with;
stored->flags = flags;
hashcpy(stored->sha1, sha1);
hash_pos = kh_put_sha1(index->bitmaps, stored->sha1, &ret);
/* a 0 return code means the insertion succeeded with no changes,
* because the SHA1 already existed on the map. this is bad, there
* shouldn't be duplicated commits in the index */
if (ret == 0) {
error("Duplicate entry in bitmap index: %s", sha1_to_hex(sha1));
return NULL;
}
kh_value(index->bitmaps, hash_pos) = stored;
return stored;
}
static inline uint32_t read_be32(const unsigned char *buffer, size_t *pos)
{
uint32_t result = get_be32(buffer + *pos);
(*pos) += sizeof(result);
return result;
}
static inline uint8_t read_u8(const unsigned char *buffer, size_t *pos)
{
return buffer[(*pos)++];
}
#define MAX_XOR_OFFSET 160
static int load_bitmap_entries_v1(struct bitmap_index *index)
{
uint32_t i;
struct stored_bitmap *recent_bitmaps[MAX_XOR_OFFSET] = { NULL };
for (i = 0; i < index->entry_count; ++i) {
int xor_offset, flags;
struct ewah_bitmap *bitmap = NULL;
struct stored_bitmap *xor_bitmap = NULL;
uint32_t commit_idx_pos;
const unsigned char *sha1;
commit_idx_pos = read_be32(index->map, &index->map_pos);
xor_offset = read_u8(index->map, &index->map_pos);
flags = read_u8(index->map, &index->map_pos);
sha1 = nth_packed_object_sha1(index->pack, commit_idx_pos);
bitmap = read_bitmap_1(index);
if (!bitmap)
return -1;
if (xor_offset > MAX_XOR_OFFSET || xor_offset > i)
return error("Corrupted bitmap pack index");
if (xor_offset > 0) {
xor_bitmap = recent_bitmaps[(i - xor_offset) % MAX_XOR_OFFSET];
if (xor_bitmap == NULL)
return error("Invalid XOR offset in bitmap pack index");
}
recent_bitmaps[i % MAX_XOR_OFFSET] = store_bitmap(
index, bitmap, sha1, xor_bitmap, flags);
}
return 0;
}
static char *pack_bitmap_filename(struct packed_git *p)
{
size_t len;
if (!strip_suffix(p->pack_name, ".pack", &len))
die("BUG: pack_name does not end in .pack");
return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
}
static int open_pack_bitmap_1(struct packed_git *packfile)
{
int fd;
struct stat st;
char *idx_name;
if (open_pack_index(packfile))
return -1;
idx_name = pack_bitmap_filename(packfile);
fd = git_open_noatime(idx_name);
free(idx_name);
if (fd < 0)
return -1;
if (fstat(fd, &st)) {
close(fd);
return -1;
}
if (bitmap_git.pack) {
warning("ignoring extra bitmap file: %s", packfile->pack_name);
close(fd);
return -1;
}
bitmap_git.pack = packfile;
bitmap_git.map_size = xsize_t(st.st_size);
bitmap_git.map = xmmap(NULL, bitmap_git.map_size, PROT_READ, MAP_PRIVATE, fd, 0);
bitmap_git.map_pos = 0;
close(fd);
if (load_bitmap_header(&bitmap_git) < 0) {
munmap(bitmap_git.map, bitmap_git.map_size);
bitmap_git.map = NULL;
bitmap_git.map_size = 0;
return -1;
}
return 0;
}
static int load_pack_bitmap(void)
{
assert(bitmap_git.map && !bitmap_git.loaded);
bitmap_git.bitmaps = kh_init_sha1();
bitmap_git.ext_index.positions = kh_init_sha1_pos();
load_pack_revindex(bitmap_git.pack);
if (!(bitmap_git.commits = read_bitmap_1(&bitmap_git)) ||
!(bitmap_git.trees = read_bitmap_1(&bitmap_git)) ||
!(bitmap_git.blobs = read_bitmap_1(&bitmap_git)) ||
!(bitmap_git.tags = read_bitmap_1(&bitmap_git)))
goto failed;
if (load_bitmap_entries_v1(&bitmap_git) < 0)
goto failed;
bitmap_git.loaded = 1;
return 0;
failed:
munmap(bitmap_git.map, bitmap_git.map_size);
bitmap_git.map = NULL;
bitmap_git.map_size = 0;
return -1;
}
static int open_pack_bitmap(void)
{
struct packed_git *p;
int ret = -1;
assert(!bitmap_git.map && !bitmap_git.loaded);
prepare_packed_git();
for (p = packed_git; p; p = p->next) {
if (open_pack_bitmap_1(p) == 0)
ret = 0;
}
return ret;
}
int prepare_bitmap_git(void)
{
if (bitmap_git.loaded)
return 0;
if (!open_pack_bitmap())
return load_pack_bitmap();
return -1;
}
struct include_data {
struct bitmap *base;
struct bitmap *seen;
};
static inline int bitmap_position_extended(const unsigned char *sha1)
{
khash_sha1_pos *positions = bitmap_git.ext_index.positions;
khiter_t pos = kh_get_sha1_pos(positions, sha1);
if (pos < kh_end(positions)) {
int bitmap_pos = kh_value(positions, pos);
return bitmap_pos + bitmap_git.pack->num_objects;
}
return -1;
}
static inline int bitmap_position_packfile(const unsigned char *sha1)
{
off_t offset = find_pack_entry_one(sha1, bitmap_git.pack);
if (!offset)
return -1;
return find_revindex_position(bitmap_git.pack, offset);
}
static int bitmap_position(const unsigned char *sha1)
{
int pos = bitmap_position_packfile(sha1);
return (pos >= 0) ? pos : bitmap_position_extended(sha1);
}
static int ext_index_add_object(struct object *object, const char *name)
{
struct eindex *eindex = &bitmap_git.ext_index;
khiter_t hash_pos;
int hash_ret;
int bitmap_pos;
hash_pos = kh_put_sha1_pos(eindex->positions, object->oid.hash, &hash_ret);
if (hash_ret > 0) {
if (eindex->count >= eindex->alloc) {
eindex->alloc = (eindex->alloc + 16) * 3 / 2;
REALLOC_ARRAY(eindex->objects, eindex->alloc);
REALLOC_ARRAY(eindex->hashes, eindex->alloc);
}
bitmap_pos = eindex->count;
eindex->objects[eindex->count] = object;
eindex->hashes[eindex->count] = pack_name_hash(name);
kh_value(eindex->positions, hash_pos) = bitmap_pos;
eindex->count++;
} else {
bitmap_pos = kh_value(eindex->positions, hash_pos);
}
return bitmap_pos + bitmap_git.pack->num_objects;
}
static void show_object(struct object *object, const char *name, void *data)
{
struct bitmap *base = data;
int bitmap_pos;
bitmap_pos = bitmap_position(object->oid.hash);
if (bitmap_pos < 0)
bitmap_pos = ext_index_add_object(object, name);
bitmap_set(base, bitmap_pos);
}
static void show_commit(struct commit *commit, void *data)
{
}
static int add_to_include_set(struct include_data *data,
const unsigned char *sha1,
int bitmap_pos)
{
khiter_t hash_pos;
if (data->seen && bitmap_get(data->seen, bitmap_pos))
return 0;
if (bitmap_get(data->base, bitmap_pos))
return 0;
hash_pos = kh_get_sha1(bitmap_git.bitmaps, sha1);
if (hash_pos < kh_end(bitmap_git.bitmaps)) {
struct stored_bitmap *st = kh_value(bitmap_git.bitmaps, hash_pos);
bitmap_or_ewah(data->base, lookup_stored_bitmap(st));
return 0;
}
bitmap_set(data->base, bitmap_pos);
return 1;
}
static int should_include(struct commit *commit, void *_data)
{
struct include_data *data = _data;
int bitmap_pos;
bitmap_pos = bitmap_position(commit->object.oid.hash);
if (bitmap_pos < 0)
bitmap_pos = ext_index_add_object((struct object *)commit, NULL);
if (!add_to_include_set(data, commit->object.oid.hash, bitmap_pos)) {
struct commit_list *parent = commit->parents;
while (parent) {
parent->item->object.flags |= SEEN;
parent = parent->next;
}
return 0;
}
return 1;
}
static struct bitmap *find_objects(struct rev_info *revs,
struct object_list *roots,
struct bitmap *seen)
{
struct bitmap *base = NULL;
int needs_walk = 0;
struct object_list *not_mapped = NULL;
/*
* Go through all the roots for the walk. The ones that have bitmaps
* on the bitmap index will be `or`ed together to form an initial
* global reachability analysis.
*
* The ones without bitmaps in the index will be stored in the
* `not_mapped_list` for further processing.
*/
while (roots) {
struct object *object = roots->item;
roots = roots->next;
if (object->type == OBJ_COMMIT) {
khiter_t pos = kh_get_sha1(bitmap_git.bitmaps, object->oid.hash);
if (pos < kh_end(bitmap_git.bitmaps)) {
struct stored_bitmap *st = kh_value(bitmap_git.bitmaps, pos);
struct ewah_bitmap *or_with = lookup_stored_bitmap(st);
if (base == NULL)
base = ewah_to_bitmap(or_with);
else
bitmap_or_ewah(base, or_with);
object->flags |= SEEN;
continue;
}
}
object_list_insert(object, &not_mapped);
}
/*
* Best case scenario: We found bitmaps for all the roots,
* so the resulting `or` bitmap has the full reachability analysis
*/
if (not_mapped == NULL)
return base;
roots = not_mapped;
/*
* Let's iterate through all the roots that don't have bitmaps to
* check if we can determine them to be reachable from the existing
* global bitmap.
*
* If we cannot find them in the existing global bitmap, we'll need
* to push them to an actual walk and run it until we can confirm
* they are reachable
*/
while (roots) {
struct object *object = roots->item;
int pos;
roots = roots->next;
pos = bitmap_position(object->oid.hash);
if (pos < 0 || base == NULL || !bitmap_get(base, pos)) {
object->flags &= ~UNINTERESTING;
add_pending_object(revs, object, "");
needs_walk = 1;
} else {
object->flags |= SEEN;
}
}
if (needs_walk) {
struct include_data incdata;
if (base == NULL)
base = bitmap_new();
incdata.base = base;
incdata.seen = seen;
revs->include_check = should_include;
revs->include_check_data = &incdata;
if (prepare_revision_walk(revs))
die("revision walk setup failed");
traverse_commit_list(revs, show_commit, show_object, base);
}
return base;
}
static void show_extended_objects(struct bitmap *objects,
show_reachable_fn show_reach)
{
struct eindex *eindex = &bitmap_git.ext_index;
uint32_t i;
for (i = 0; i < eindex->count; ++i) {
struct object *obj;
if (!bitmap_get(objects, bitmap_git.pack->num_objects + i))
continue;
obj = eindex->objects[i];
show_reach(obj->oid.hash, obj->type, 0, eindex->hashes[i], NULL, 0);
}
}
static void show_objects_for_type(
struct bitmap *objects,
struct ewah_bitmap *type_filter,
enum object_type object_type,
show_reachable_fn show_reach)
{
size_t pos = 0, i = 0;
uint32_t offset;
struct ewah_iterator it;
eword_t filter;
if (bitmap_git.reuse_objects == bitmap_git.pack->num_objects)
return;
ewah_iterator_init(&it, type_filter);
while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
eword_t word = objects->words[i] & filter;
for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
const unsigned char *sha1;
struct revindex_entry *entry;
uint32_t hash = 0;
if ((word >> offset) == 0)
break;
offset += ewah_bit_ctz64(word >> offset);
if (pos + offset < bitmap_git.reuse_objects)
continue;
entry = &bitmap_git.pack->revindex[pos + offset];
sha1 = nth_packed_object_sha1(bitmap_git.pack, entry->nr);
if (bitmap_git.hashes)
hash = get_be32(bitmap_git.hashes + entry->nr);
show_reach(sha1, object_type, 0, hash, bitmap_git.pack, entry->offset);
}
pos += BITS_IN_EWORD;
i++;
}
}
static int in_bitmapped_pack(struct object_list *roots)
{
while (roots) {
struct object *object = roots->item;
roots = roots->next;
if (find_pack_entry_one(object->oid.hash, bitmap_git.pack) > 0)
return 1;
}
return 0;
}
int prepare_bitmap_walk(struct rev_info *revs)
{
unsigned int i;
unsigned int pending_nr = revs->pending.nr;
struct object_array_entry *pending_e = revs->pending.objects;
struct object_list *wants = NULL;
struct object_list *haves = NULL;
struct bitmap *wants_bitmap = NULL;
struct bitmap *haves_bitmap = NULL;
if (!bitmap_git.loaded) {
/* try to open a bitmapped pack, but don't parse it yet
* because we may not need to use it */
if (open_pack_bitmap() < 0)
return -1;
}
for (i = 0; i < pending_nr; ++i) {
struct object *object = pending_e[i].item;
if (object->type == OBJ_NONE)
parse_object_or_die(object->oid.hash, NULL);
while (object->type == OBJ_TAG) {
struct tag *tag = (struct tag *) object;
if (object->flags & UNINTERESTING)
object_list_insert(object, &haves);
else
object_list_insert(object, &wants);
if (!tag->tagged)
die("bad tag");
object = parse_object_or_die(tag->tagged->oid.hash, NULL);
}
if (object->flags & UNINTERESTING)
object_list_insert(object, &haves);
else
object_list_insert(object, &wants);
}
/*
* if we have a HAVES list, but none of those haves is contained
* in the packfile that has a bitmap, we don't have anything to
* optimize here
*/
if (haves && !in_bitmapped_pack(haves))
return -1;
/* if we don't want anything, we're done here */
if (!wants)
return -1;
/*
* now we're going to use bitmaps, so load the actual bitmap entries
* from disk. this is the point of no return; after this the rev_list
* becomes invalidated and we must perform the revwalk through bitmaps
*/
if (!bitmap_git.loaded && load_pack_bitmap() < 0)
return -1;
revs->pending.nr = 0;
revs->pending.alloc = 0;
revs->pending.objects = NULL;
if (haves) {
revs->ignore_missing_links = 1;
haves_bitmap = find_objects(revs, haves, NULL);
reset_revision_walk();
revs->ignore_missing_links = 0;
if (haves_bitmap == NULL)
die("BUG: failed to perform bitmap walk");
}
wants_bitmap = find_objects(revs, wants, haves_bitmap);
if (!wants_bitmap)
die("BUG: failed to perform bitmap walk");
if (haves_bitmap)
bitmap_and_not(wants_bitmap, haves_bitmap);
bitmap_git.result = wants_bitmap;
bitmap_free(haves_bitmap);
return 0;
}
int reuse_partial_packfile_from_bitmap(struct packed_git **packfile,
uint32_t *entries,
off_t *up_to)
{
/*
* Reuse the packfile content if we need more than
* 90% of its objects
*/
static const double REUSE_PERCENT = 0.9;
struct bitmap *result = bitmap_git.result;
uint32_t reuse_threshold;
uint32_t i, reuse_objects = 0;
assert(result);
for (i = 0; i < result->word_alloc; ++i) {
if (result->words[i] != (eword_t)~0) {
reuse_objects += ewah_bit_ctz64(~result->words[i]);
break;
}
reuse_objects += BITS_IN_EWORD;
}
#ifdef GIT_BITMAP_DEBUG
{
const unsigned char *sha1;
struct revindex_entry *entry;
entry = &bitmap_git.reverse_index->revindex[reuse_objects];
sha1 = nth_packed_object_sha1(bitmap_git.pack, entry->nr);
fprintf(stderr, "Failed to reuse at %d (%016llx)\n",
reuse_objects, result->words[i]);
fprintf(stderr, " %s\n", sha1_to_hex(sha1));
}
#endif
if (!reuse_objects)
return -1;
if (reuse_objects >= bitmap_git.pack->num_objects) {
bitmap_git.reuse_objects = *entries = bitmap_git.pack->num_objects;
*up_to = -1; /* reuse the full pack */
*packfile = bitmap_git.pack;
return 0;
}
reuse_threshold = bitmap_popcount(bitmap_git.result) * REUSE_PERCENT;
if (reuse_objects < reuse_threshold)
return -1;
bitmap_git.reuse_objects = *entries = reuse_objects;
*up_to = bitmap_git.pack->revindex[reuse_objects].offset;
*packfile = bitmap_git.pack;
return 0;
}
void traverse_bitmap_commit_list(show_reachable_fn show_reachable)
{
assert(bitmap_git.result);
show_objects_for_type(bitmap_git.result, bitmap_git.commits,
OBJ_COMMIT, show_reachable);
show_objects_for_type(bitmap_git.result, bitmap_git.trees,
OBJ_TREE, show_reachable);
show_objects_for_type(bitmap_git.result, bitmap_git.blobs,
OBJ_BLOB, show_reachable);
show_objects_for_type(bitmap_git.result, bitmap_git.tags,
OBJ_TAG, show_reachable);
show_extended_objects(bitmap_git.result, show_reachable);
bitmap_free(bitmap_git.result);
bitmap_git.result = NULL;
}
static uint32_t count_object_type(struct bitmap *objects,
enum object_type type)
{
struct eindex *eindex = &bitmap_git.ext_index;
uint32_t i = 0, count = 0;
struct ewah_iterator it;
eword_t filter;
switch (type) {
case OBJ_COMMIT:
ewah_iterator_init(&it, bitmap_git.commits);
break;
case OBJ_TREE:
ewah_iterator_init(&it, bitmap_git.trees);
break;
case OBJ_BLOB:
ewah_iterator_init(&it, bitmap_git.blobs);
break;
case OBJ_TAG:
ewah_iterator_init(&it, bitmap_git.tags);
break;
default:
return 0;
}
while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
eword_t word = objects->words[i++] & filter;
count += ewah_bit_popcount64(word);
}
for (i = 0; i < eindex->count; ++i) {
if (eindex->objects[i]->type == type &&
bitmap_get(objects, bitmap_git.pack->num_objects + i))
count++;
}
return count;
}
void count_bitmap_commit_list(uint32_t *commits, uint32_t *trees,
uint32_t *blobs, uint32_t *tags)
{
assert(bitmap_git.result);
if (commits)
*commits = count_object_type(bitmap_git.result, OBJ_COMMIT);
if (trees)
*trees = count_object_type(bitmap_git.result, OBJ_TREE);
if (blobs)
*blobs = count_object_type(bitmap_git.result, OBJ_BLOB);
if (tags)
*tags = count_object_type(bitmap_git.result, OBJ_TAG);
}
struct bitmap_test_data {
struct bitmap *base;
struct progress *prg;
size_t seen;
};
static void test_show_object(struct object *object, const char *name,
void *data)
{
struct bitmap_test_data *tdata = data;
int bitmap_pos;
bitmap_pos = bitmap_position(object->oid.hash);
if (bitmap_pos < 0)
die("Object not in bitmap: %s\n", oid_to_hex(&object->oid));
bitmap_set(tdata->base, bitmap_pos);
display_progress(tdata->prg, ++tdata->seen);
}
static void test_show_commit(struct commit *commit, void *data)
{
struct bitmap_test_data *tdata = data;
int bitmap_pos;
bitmap_pos = bitmap_position(commit->object.oid.hash);
if (bitmap_pos < 0)
die("Object not in bitmap: %s\n", oid_to_hex(&commit->object.oid));
bitmap_set(tdata->base, bitmap_pos);
display_progress(tdata->prg, ++tdata->seen);
}
void test_bitmap_walk(struct rev_info *revs)
{
struct object *root;
struct bitmap *result = NULL;
khiter_t pos;
size_t result_popcnt;
struct bitmap_test_data tdata;
if (prepare_bitmap_git())
die("failed to load bitmap indexes");
if (revs->pending.nr != 1)
die("you must specify exactly one commit to test");
fprintf(stderr, "Bitmap v%d test (%d entries loaded)\n",
bitmap_git.version, bitmap_git.entry_count);
root = revs->pending.objects[0].item;
pos = kh_get_sha1(bitmap_git.bitmaps, root->oid.hash);
if (pos < kh_end(bitmap_git.bitmaps)) {
struct stored_bitmap *st = kh_value(bitmap_git.bitmaps, pos);
struct ewah_bitmap *bm = lookup_stored_bitmap(st);
fprintf(stderr, "Found bitmap for %s. %d bits / %08x checksum\n",
oid_to_hex(&root->oid), (int)bm->bit_size, ewah_checksum(bm));
result = ewah_to_bitmap(bm);
}
if (result == NULL)
die("Commit %s doesn't have an indexed bitmap", oid_to_hex(&root->oid));
revs->tag_objects = 1;
revs->tree_objects = 1;
revs->blob_objects = 1;
result_popcnt = bitmap_popcount(result);
if (prepare_revision_walk(revs))
die("revision walk setup failed");
tdata.base = bitmap_new();
tdata.prg = start_progress("Verifying bitmap entries", result_popcnt);
tdata.seen = 0;
traverse_commit_list(revs, &test_show_commit, &test_show_object, &tdata);
stop_progress(&tdata.prg);
if (bitmap_equals(result, tdata.base))
fprintf(stderr, "OK!\n");
else
fprintf(stderr, "Mismatch!\n");
bitmap_free(result);
}
static int rebuild_bitmap(uint32_t *reposition,
struct ewah_bitmap *source,
struct bitmap *dest)
{
uint32_t pos = 0;
struct ewah_iterator it;
eword_t word;
ewah_iterator_init(&it, source);
while (ewah_iterator_next(&word, &it)) {
uint32_t offset, bit_pos;
for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
if ((word >> offset) == 0)
break;
offset += ewah_bit_ctz64(word >> offset);
bit_pos = reposition[pos + offset];
if (bit_pos > 0)
bitmap_set(dest, bit_pos - 1);
else /* can't reuse, we don't have the object */
return -1;
}
pos += BITS_IN_EWORD;
}
return 0;
}
int rebuild_existing_bitmaps(struct packing_data *mapping,
khash_sha1 *reused_bitmaps,
int show_progress)
{
uint32_t i, num_objects;
uint32_t *reposition;
struct bitmap *rebuild;
struct stored_bitmap *stored;
struct progress *progress = NULL;
khiter_t hash_pos;
int hash_ret;
if (prepare_bitmap_git() < 0)
return -1;
num_objects = bitmap_git.pack->num_objects;
reposition = xcalloc(num_objects, sizeof(uint32_t));
for (i = 0; i < num_objects; ++i) {
const unsigned char *sha1;
struct revindex_entry *entry;
struct object_entry *oe;
entry = &bitmap_git.pack->revindex[i];
sha1 = nth_packed_object_sha1(bitmap_git.pack, entry->nr);
oe = packlist_find(mapping, sha1, NULL);
if (oe)
reposition[i] = oe->in_pack_pos + 1;
}
rebuild = bitmap_new();
i = 0;
if (show_progress)
progress = start_progress("Reusing bitmaps", 0);
kh_foreach_value(bitmap_git.bitmaps, stored, {
if (stored->flags & BITMAP_FLAG_REUSE) {
if (!rebuild_bitmap(reposition,
lookup_stored_bitmap(stored),
rebuild)) {
hash_pos = kh_put_sha1(reused_bitmaps,
stored->sha1,
&hash_ret);
kh_value(reused_bitmaps, hash_pos) =
bitmap_to_ewah(rebuild);
}
bitmap_reset(rebuild);
display_progress(progress, ++i);
}
});
stop_progress(&progress);
free(reposition);
bitmap_free(rebuild);
return 0;
}