git/pack-bitmap.c
Derrick Stolee 756f1bcd29 fsck: verify checksums of all .bitmap files
If a filesystem-level corruption occurs in a .bitmap file, Git can react
poorly. This could take the form of a run-time error due to failing to
parse an EWAH bitmap or be more subtle such as returning the wrong set
of objects to a fetch or clone.

A natural first response to either of these kinds of errors is to run
'git fsck' to see if any files are corrupt. This currently ignores all
.bitmap files.

Add checks to 'git fsck' for all .bitmap files that are currently
associated with a multi-pack-index or pack file. Verify their checksums
using the hashfile API.

We iterate through all multi-pack-indexes and pack-files to be sure to
check all .bitmap files, not just the one that would be read by the
process. For example, a multi-pack-index bitmap overrules a pack-bitmap.
However, if the multi-pack-index is removed, the pack-bitmap may be
selected instead. Be thorough to include every file that could become
active in such a way. This includes checking files in alternates.

There is potential that we could extend this effort to check the
structure of the reachability bitmaps themselves, but it is very
expensive to do so. At minimum, it's as expensive as generating the
bitmaps in the first place, and that's assuming that we don't use the
trivial algorithm of verifying each bitmap individually. The trivial
algorithm will result in quadratic behavior (number of objects times
number of bitmapped commits) while the bitmap building operation
constructs a lattice of commits to build bitmaps incrementally and then
generate the final bitmaps from a subset of those commits.

If we were to extend 'git fsck' to check .bitmap file contents more
closely like this, then we would likely want to hide it behind an option
that signals the user is more willing to do expensive operations such as
this.

For testing, set up a repository with a pack-bitmap _and_ a
multi-pack-index bitmap. This requires some file movement to avoid
deleting the pack-bitmap during the repack that creates the
multi-pack-index bitmap. We can then verify that 'git fsck' is checking
all files, not just the "active" bitmap.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-05-02 08:48:22 -07:00

2394 lines
61 KiB
C

#include "git-compat-util.h"
#include "alloc.h"
#include "commit.h"
#include "gettext.h"
#include "hex.h"
#include "strbuf.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"
#include "packfile.h"
#include "repository.h"
#include "trace2.h"
#include "object-file.h"
#include "object-store.h"
#include "list-objects-filter-options.h"
#include "midx.h"
#include "config.h"
/*
* An entry on the bitmap index, representing the bitmap for a given
* commit.
*/
struct stored_bitmap {
struct object_id oid;
struct ewah_bitmap *root;
struct stored_bitmap *xor;
int flags;
};
/*
* The active bitmap index for a repository. 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.
*/
struct bitmap_index {
/*
* The pack or multi-pack index (MIDX) that this bitmap index belongs
* to.
*
* Exactly one of these must be non-NULL; this specifies the object
* order used to interpret this bitmap.
*/
struct packed_git *pack;
struct multi_pack_index *midx;
/*
* 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 object ID -> `stored_bitmap` for all the bitmapped commits */
kh_oid_map_t *bitmaps;
/* Number of bitmapped commits */
uint32_t entry_count;
/* If not NULL, this is a name-hash cache pointing into map. */
uint32_t *hashes;
/* The checksum of the packfile or MIDX; points into map. */
const unsigned char *checksum;
/*
* If not NULL, this point into the commit table extension
* (within the memory mapped region `map`).
*/
unsigned char *table_lookup;
/*
* 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;
kh_oid_pos_t *positions;
} ext_index;
/* Bitmap result of the last performed walk */
struct bitmap *result;
/* "have" bitmap from the last performed walk */
struct bitmap *haves;
/* Version of the bitmap index */
unsigned int version;
};
static struct ewah_bitmap *lookup_stored_bitmap(struct stored_bitmap *st)
{
struct ewah_bitmap *parent;
struct ewah_bitmap *composed;
if (!st->xor)
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();
ssize_t 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 uint32_t bitmap_num_objects(struct bitmap_index *index)
{
if (index->midx)
return index->midx->num_objects;
return index->pack->num_objects;
}
static int load_bitmap_header(struct bitmap_index *index)
{
struct bitmap_disk_header *header = (void *)index->map;
size_t header_size = sizeof(*header) - GIT_MAX_RAWSZ + the_hash_algo->rawsz;
if (index->map_size < header_size + the_hash_algo->rawsz)
return error(_("corrupted bitmap index (too small)"));
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 '%d' for bitmap index file"), index->version);
/* Parse known bitmap format options */
{
uint32_t flags = ntohs(header->options);
size_t cache_size = st_mult(bitmap_num_objects(index), sizeof(uint32_t));
unsigned char *index_end = index->map + index->map_size - the_hash_algo->rawsz;
if ((flags & BITMAP_OPT_FULL_DAG) == 0)
BUG("unsupported options for bitmap index file "
"(Git requires BITMAP_OPT_FULL_DAG)");
if (flags & BITMAP_OPT_HASH_CACHE) {
if (cache_size > index_end - index->map - header_size)
return error(_("corrupted bitmap index file (too short to fit hash cache)"));
index->hashes = (void *)(index_end - cache_size);
index_end -= cache_size;
}
if (flags & BITMAP_OPT_LOOKUP_TABLE) {
size_t table_size = st_mult(ntohl(header->entry_count),
BITMAP_LOOKUP_TABLE_TRIPLET_WIDTH);
if (table_size > index_end - index->map - header_size)
return error(_("corrupted bitmap index file (too short to fit lookup table)"));
if (git_env_bool("GIT_TEST_READ_COMMIT_TABLE", 1))
index->table_lookup = (void *)(index_end - table_size);
index_end -= table_size;
}
}
index->entry_count = ntohl(header->entry_count);
index->checksum = header->checksum;
index->map_pos += header_size;
return 0;
}
static struct stored_bitmap *store_bitmap(struct bitmap_index *index,
struct ewah_bitmap *root,
const struct object_id *oid,
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;
oidcpy(&stored->oid, oid);
hash_pos = kh_put_oid_map(index->bitmaps, stored->oid, &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'"), oid_to_hex(oid));
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 nth_bitmap_object_oid(struct bitmap_index *index,
struct object_id *oid,
uint32_t n)
{
if (index->midx)
return nth_midxed_object_oid(oid, index->midx, n) ? 0 : -1;
return nth_packed_object_id(oid, index->pack, n);
}
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;
struct object_id oid;
if (index->map_size - index->map_pos < 6)
return error(_("corrupt ewah bitmap: truncated header for entry %d"), i);
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);
if (nth_bitmap_object_oid(index, &oid, commit_idx_pos) < 0)
return error(_("corrupt ewah bitmap: commit index %u out of range"),
(unsigned)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)
return error(_("invalid XOR offset in bitmap pack index"));
}
recent_bitmaps[i % MAX_XOR_OFFSET] = store_bitmap(
index, bitmap, &oid, xor_bitmap, flags);
}
return 0;
}
char *midx_bitmap_filename(struct multi_pack_index *midx)
{
struct strbuf buf = STRBUF_INIT;
get_midx_filename(&buf, midx->object_dir);
strbuf_addf(&buf, "-%s.bitmap", hash_to_hex(get_midx_checksum(midx)));
return strbuf_detach(&buf, NULL);
}
char *pack_bitmap_filename(struct packed_git *p)
{
size_t len;
if (!strip_suffix(p->pack_name, ".pack", &len))
BUG("pack_name does not end in .pack");
return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
}
static int open_midx_bitmap_1(struct bitmap_index *bitmap_git,
struct multi_pack_index *midx)
{
struct stat st;
char *bitmap_name = midx_bitmap_filename(midx);
int fd = git_open(bitmap_name);
uint32_t i;
struct packed_git *preferred;
if (fd < 0) {
if (errno != ENOENT)
warning_errno("cannot open '%s'", bitmap_name);
free(bitmap_name);
return -1;
}
free(bitmap_name);
if (fstat(fd, &st)) {
error_errno(_("cannot fstat bitmap file"));
close(fd);
return -1;
}
if (bitmap_git->pack || bitmap_git->midx) {
struct strbuf buf = STRBUF_INIT;
get_midx_filename(&buf, midx->object_dir);
trace2_data_string("bitmap", the_repository,
"ignoring extra midx bitmap file", buf.buf);
close(fd);
strbuf_release(&buf);
return -1;
}
bitmap_git->midx = midx;
bitmap_git->map_size = xsize_t(st.st_size);
bitmap_git->map_pos = 0;
bitmap_git->map = xmmap(NULL, bitmap_git->map_size, PROT_READ,
MAP_PRIVATE, fd, 0);
close(fd);
if (load_bitmap_header(bitmap_git) < 0)
goto cleanup;
if (!hasheq(get_midx_checksum(bitmap_git->midx), bitmap_git->checksum)) {
error(_("checksum doesn't match in MIDX and bitmap"));
goto cleanup;
}
if (load_midx_revindex(bitmap_git->midx)) {
warning(_("multi-pack bitmap is missing required reverse index"));
goto cleanup;
}
for (i = 0; i < bitmap_git->midx->num_packs; i++) {
if (prepare_midx_pack(the_repository, bitmap_git->midx, i))
die(_("could not open pack %s"),
bitmap_git->midx->pack_names[i]);
}
preferred = bitmap_git->midx->packs[midx_preferred_pack(bitmap_git)];
if (!is_pack_valid(preferred)) {
warning(_("preferred pack (%s) is invalid"),
preferred->pack_name);
goto cleanup;
}
return 0;
cleanup:
munmap(bitmap_git->map, bitmap_git->map_size);
bitmap_git->map_size = 0;
bitmap_git->map_pos = 0;
bitmap_git->map = NULL;
bitmap_git->midx = NULL;
return -1;
}
static int open_pack_bitmap_1(struct bitmap_index *bitmap_git, struct packed_git *packfile)
{
int fd;
struct stat st;
char *bitmap_name;
bitmap_name = pack_bitmap_filename(packfile);
fd = git_open(bitmap_name);
if (fd < 0) {
if (errno != ENOENT)
warning_errno("cannot open '%s'", bitmap_name);
free(bitmap_name);
return -1;
}
free(bitmap_name);
if (fstat(fd, &st)) {
error_errno(_("cannot fstat bitmap file"));
close(fd);
return -1;
}
if (bitmap_git->pack || bitmap_git->midx) {
trace2_data_string("bitmap", the_repository,
"ignoring extra bitmap file", packfile->pack_name);
close(fd);
return -1;
}
if (!is_pack_valid(packfile)) {
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;
bitmap_git->map_pos = 0;
bitmap_git->pack = NULL;
return -1;
}
trace2_data_string("bitmap", the_repository, "opened bitmap file",
packfile->pack_name);
return 0;
}
static int load_reverse_index(struct repository *r, struct bitmap_index *bitmap_git)
{
if (bitmap_is_midx(bitmap_git)) {
uint32_t i;
int ret;
/*
* The multi-pack-index's .rev file is already loaded via
* open_pack_bitmap_1().
*
* But we still need to open the individual pack .rev files,
* since we will need to make use of them in pack-objects.
*/
for (i = 0; i < bitmap_git->midx->num_packs; i++) {
ret = load_pack_revindex(r, bitmap_git->midx->packs[i]);
if (ret)
return ret;
}
return 0;
}
return load_pack_revindex(r, bitmap_git->pack);
}
static int load_bitmap(struct repository *r, struct bitmap_index *bitmap_git)
{
assert(bitmap_git->map);
bitmap_git->bitmaps = kh_init_oid_map();
bitmap_git->ext_index.positions = kh_init_oid_pos();
if (load_reverse_index(r, bitmap_git))
goto failed;
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 (!bitmap_git->table_lookup && load_bitmap_entries_v1(bitmap_git) < 0)
goto failed;
return 0;
failed:
munmap(bitmap_git->map, bitmap_git->map_size);
bitmap_git->map = NULL;
bitmap_git->map_size = 0;
kh_destroy_oid_map(bitmap_git->bitmaps);
bitmap_git->bitmaps = NULL;
kh_destroy_oid_pos(bitmap_git->ext_index.positions);
bitmap_git->ext_index.positions = NULL;
return -1;
}
static int open_pack_bitmap(struct repository *r,
struct bitmap_index *bitmap_git)
{
struct packed_git *p;
int ret = -1;
for (p = get_all_packs(r); p; p = p->next) {
if (open_pack_bitmap_1(bitmap_git, p) == 0) {
ret = 0;
/*
* The only reason to keep looking is to report
* duplicates.
*/
if (!trace2_is_enabled())
break;
}
}
return ret;
}
static int open_midx_bitmap(struct repository *r,
struct bitmap_index *bitmap_git)
{
int ret = -1;
struct multi_pack_index *midx;
assert(!bitmap_git->map);
for (midx = get_multi_pack_index(r); midx; midx = midx->next) {
if (!open_midx_bitmap_1(bitmap_git, midx))
ret = 0;
}
return ret;
}
static int open_bitmap(struct repository *r,
struct bitmap_index *bitmap_git)
{
int found;
assert(!bitmap_git->map);
found = !open_midx_bitmap(r, bitmap_git);
/*
* these will all be skipped if we opened a midx bitmap; but run it
* anyway if tracing is enabled to report the duplicates
*/
if (!found || trace2_is_enabled())
found |= !open_pack_bitmap(r, bitmap_git);
return found ? 0 : -1;
}
struct bitmap_index *prepare_bitmap_git(struct repository *r)
{
struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
if (!open_bitmap(r, bitmap_git) && !load_bitmap(r, bitmap_git))
return bitmap_git;
free_bitmap_index(bitmap_git);
return NULL;
}
struct bitmap_index *prepare_midx_bitmap_git(struct multi_pack_index *midx)
{
struct repository *r = the_repository;
struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
if (!open_midx_bitmap_1(bitmap_git, midx) && !load_bitmap(r, bitmap_git))
return bitmap_git;
free_bitmap_index(bitmap_git);
return NULL;
}
struct include_data {
struct bitmap_index *bitmap_git;
struct bitmap *base;
struct bitmap *seen;
};
struct bitmap_lookup_table_triplet {
uint32_t commit_pos;
uint64_t offset;
uint32_t xor_row;
};
struct bitmap_lookup_table_xor_item {
struct object_id oid;
uint64_t offset;
};
/*
* Given a `triplet` struct pointer and pointer `p`, this
* function reads the triplet beginning at `p` into the struct.
* Note that this function assumes that there is enough memory
* left for filling the `triplet` struct from `p`.
*/
static int bitmap_lookup_table_get_triplet_by_pointer(struct bitmap_lookup_table_triplet *triplet,
const unsigned char *p)
{
if (!triplet)
return -1;
triplet->commit_pos = get_be32(p);
p += sizeof(uint32_t);
triplet->offset = get_be64(p);
p += sizeof(uint64_t);
triplet->xor_row = get_be32(p);
return 0;
}
/*
* This function gets the raw triplet from `row`'th row in the
* lookup table and fills that data to the `triplet`.
*/
static int bitmap_lookup_table_get_triplet(struct bitmap_index *bitmap_git,
uint32_t pos,
struct bitmap_lookup_table_triplet *triplet)
{
unsigned char *p = NULL;
if (pos >= bitmap_git->entry_count)
return error(_("corrupt bitmap lookup table: triplet position out of index"));
p = bitmap_git->table_lookup + st_mult(pos, BITMAP_LOOKUP_TABLE_TRIPLET_WIDTH);
return bitmap_lookup_table_get_triplet_by_pointer(triplet, p);
}
/*
* Searches for a matching triplet. `commit_pos` is a pointer
* to the wanted commit position value. `table_entry` points to
* a triplet in lookup table. The first 4 bytes of each
* triplet (pointed by `table_entry`) are compared with `*commit_pos`.
*/
static int triplet_cmp(const void *commit_pos, const void *table_entry)
{
uint32_t a = *(uint32_t *)commit_pos;
uint32_t b = get_be32(table_entry);
if (a > b)
return 1;
else if (a < b)
return -1;
return 0;
}
static uint32_t bitmap_bsearch_pos(struct bitmap_index *bitmap_git,
struct object_id *oid,
uint32_t *result)
{
int found;
if (bitmap_is_midx(bitmap_git))
found = bsearch_midx(oid, bitmap_git->midx, result);
else
found = bsearch_pack(oid, bitmap_git->pack, result);
return found;
}
/*
* `bsearch_triplet_by_pos` function searches for the raw triplet
* having commit position same as `commit_pos` and fills `triplet`
* object from the raw triplet. Returns 1 on success and 0 on
* failure.
*/
static int bitmap_bsearch_triplet_by_pos(uint32_t commit_pos,
struct bitmap_index *bitmap_git,
struct bitmap_lookup_table_triplet *triplet)
{
unsigned char *p = bsearch(&commit_pos, bitmap_git->table_lookup, bitmap_git->entry_count,
BITMAP_LOOKUP_TABLE_TRIPLET_WIDTH, triplet_cmp);
if (!p)
return -1;
return bitmap_lookup_table_get_triplet_by_pointer(triplet, p);
}
static struct stored_bitmap *lazy_bitmap_for_commit(struct bitmap_index *bitmap_git,
struct commit *commit)
{
uint32_t commit_pos, xor_row;
uint64_t offset;
int flags;
struct bitmap_lookup_table_triplet triplet;
struct object_id *oid = &commit->object.oid;
struct ewah_bitmap *bitmap;
struct stored_bitmap *xor_bitmap = NULL;
const int bitmap_header_size = 6;
static struct bitmap_lookup_table_xor_item *xor_items = NULL;
static size_t xor_items_nr = 0, xor_items_alloc = 0;
static int is_corrupt = 0;
int xor_flags;
khiter_t hash_pos;
struct bitmap_lookup_table_xor_item *xor_item;
if (is_corrupt)
return NULL;
if (!bitmap_bsearch_pos(bitmap_git, oid, &commit_pos))
return NULL;
if (bitmap_bsearch_triplet_by_pos(commit_pos, bitmap_git, &triplet) < 0)
return NULL;
xor_items_nr = 0;
offset = triplet.offset;
xor_row = triplet.xor_row;
while (xor_row != 0xffffffff) {
ALLOC_GROW(xor_items, xor_items_nr + 1, xor_items_alloc);
if (xor_items_nr + 1 >= bitmap_git->entry_count) {
error(_("corrupt bitmap lookup table: xor chain exceeds entry count"));
goto corrupt;
}
if (bitmap_lookup_table_get_triplet(bitmap_git, xor_row, &triplet) < 0)
goto corrupt;
xor_item = &xor_items[xor_items_nr];
xor_item->offset = triplet.offset;
if (nth_bitmap_object_oid(bitmap_git, &xor_item->oid, triplet.commit_pos) < 0) {
error(_("corrupt bitmap lookup table: commit index %u out of range"),
triplet.commit_pos);
goto corrupt;
}
hash_pos = kh_get_oid_map(bitmap_git->bitmaps, xor_item->oid);
/*
* If desired bitmap is already stored, we don't need
* to iterate further. Because we know that bitmaps
* that are needed to be parsed to parse this bitmap
* has already been stored. So, assign this stored bitmap
* to the xor_bitmap.
*/
if (hash_pos < kh_end(bitmap_git->bitmaps) &&
(xor_bitmap = kh_value(bitmap_git->bitmaps, hash_pos)))
break;
xor_items_nr++;
xor_row = triplet.xor_row;
}
while (xor_items_nr) {
xor_item = &xor_items[xor_items_nr - 1];
bitmap_git->map_pos = xor_item->offset;
if (bitmap_git->map_size - bitmap_git->map_pos < bitmap_header_size) {
error(_("corrupt ewah bitmap: truncated header for bitmap of commit \"%s\""),
oid_to_hex(&xor_item->oid));
goto corrupt;
}
bitmap_git->map_pos += sizeof(uint32_t) + sizeof(uint8_t);
xor_flags = read_u8(bitmap_git->map, &bitmap_git->map_pos);
bitmap = read_bitmap_1(bitmap_git);
if (!bitmap)
goto corrupt;
xor_bitmap = store_bitmap(bitmap_git, bitmap, &xor_item->oid, xor_bitmap, xor_flags);
xor_items_nr--;
}
bitmap_git->map_pos = offset;
if (bitmap_git->map_size - bitmap_git->map_pos < bitmap_header_size) {
error(_("corrupt ewah bitmap: truncated header for bitmap of commit \"%s\""),
oid_to_hex(oid));
goto corrupt;
}
/*
* Don't bother reading the commit's index position or its xor
* offset:
*
* - The commit's index position is irrelevant to us, since
* load_bitmap_entries_v1 only uses it to learn the object
* id which is used to compute the hashmap's key. We already
* have an object id, so no need to look it up again.
*
* - The xor_offset is unusable for us, since it specifies how
* many entries previous to ours we should look at. This
* makes sense when reading the bitmaps sequentially (as in
* load_bitmap_entries_v1()), since we can keep track of
* each bitmap as we read them.
*
* But it can't work for us, since the bitmap's don't have a
* fixed size. So we learn the position of the xor'd bitmap
* from the commit table (and resolve it to a bitmap in the
* above if-statement).
*
* Instead, we can skip ahead and immediately read the flags and
* ewah bitmap.
*/
bitmap_git->map_pos += sizeof(uint32_t) + sizeof(uint8_t);
flags = read_u8(bitmap_git->map, &bitmap_git->map_pos);
bitmap = read_bitmap_1(bitmap_git);
if (!bitmap)
goto corrupt;
return store_bitmap(bitmap_git, bitmap, oid, xor_bitmap, flags);
corrupt:
free(xor_items);
is_corrupt = 1;
return NULL;
}
struct ewah_bitmap *bitmap_for_commit(struct bitmap_index *bitmap_git,
struct commit *commit)
{
khiter_t hash_pos = kh_get_oid_map(bitmap_git->bitmaps,
commit->object.oid);
if (hash_pos >= kh_end(bitmap_git->bitmaps)) {
struct stored_bitmap *bitmap = NULL;
if (!bitmap_git->table_lookup)
return NULL;
/* this is a fairly hot codepath - no trace2_region please */
/* NEEDSWORK: cache misses aren't recorded */
bitmap = lazy_bitmap_for_commit(bitmap_git, commit);
if (!bitmap)
return NULL;
return lookup_stored_bitmap(bitmap);
}
return lookup_stored_bitmap(kh_value(bitmap_git->bitmaps, hash_pos));
}
static inline int bitmap_position_extended(struct bitmap_index *bitmap_git,
const struct object_id *oid)
{
kh_oid_pos_t *positions = bitmap_git->ext_index.positions;
khiter_t pos = kh_get_oid_pos(positions, *oid);
if (pos < kh_end(positions)) {
int bitmap_pos = kh_value(positions, pos);
return bitmap_pos + bitmap_num_objects(bitmap_git);
}
return -1;
}
static inline int bitmap_position_packfile(struct bitmap_index *bitmap_git,
const struct object_id *oid)
{
uint32_t pos;
off_t offset = find_pack_entry_one(oid->hash, bitmap_git->pack);
if (!offset)
return -1;
if (offset_to_pack_pos(bitmap_git->pack, offset, &pos) < 0)
return -1;
return pos;
}
static int bitmap_position_midx(struct bitmap_index *bitmap_git,
const struct object_id *oid)
{
uint32_t want, got;
if (!bsearch_midx(oid, bitmap_git->midx, &want))
return -1;
if (midx_to_pack_pos(bitmap_git->midx, want, &got) < 0)
return -1;
return got;
}
static int bitmap_position(struct bitmap_index *bitmap_git,
const struct object_id *oid)
{
int pos;
if (bitmap_is_midx(bitmap_git))
pos = bitmap_position_midx(bitmap_git, oid);
else
pos = bitmap_position_packfile(bitmap_git, oid);
return (pos >= 0) ? pos : bitmap_position_extended(bitmap_git, oid);
}
static int ext_index_add_object(struct bitmap_index *bitmap_git,
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_oid_pos(eindex->positions, object->oid, &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_num_objects(bitmap_git);
}
struct bitmap_show_data {
struct bitmap_index *bitmap_git;
struct bitmap *base;
};
static void show_object(struct object *object, const char *name, void *data_)
{
struct bitmap_show_data *data = data_;
int bitmap_pos;
bitmap_pos = bitmap_position(data->bitmap_git, &object->oid);
if (bitmap_pos < 0)
bitmap_pos = ext_index_add_object(data->bitmap_git, object,
name);
bitmap_set(data->base, bitmap_pos);
}
static void show_commit(struct commit *commit UNUSED,
void *data UNUSED)
{
}
static int add_to_include_set(struct bitmap_index *bitmap_git,
struct include_data *data,
struct commit *commit,
int bitmap_pos)
{
struct ewah_bitmap *partial;
if (data->seen && bitmap_get(data->seen, bitmap_pos))
return 0;
if (bitmap_get(data->base, bitmap_pos))
return 0;
partial = bitmap_for_commit(bitmap_git, commit);
if (partial) {
bitmap_or_ewah(data->base, partial);
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(data->bitmap_git, &commit->object.oid);
if (bitmap_pos < 0)
bitmap_pos = ext_index_add_object(data->bitmap_git,
(struct object *)commit,
NULL);
if (!add_to_include_set(data->bitmap_git, data, commit, bitmap_pos)) {
struct commit_list *parent = commit->parents;
while (parent) {
parent->item->object.flags |= SEEN;
parent = parent->next;
}
return 0;
}
return 1;
}
static int should_include_obj(struct object *obj, void *_data)
{
struct include_data *data = _data;
int bitmap_pos;
bitmap_pos = bitmap_position(data->bitmap_git, &obj->oid);
if (bitmap_pos < 0)
return 1;
if ((data->seen && bitmap_get(data->seen, bitmap_pos)) ||
bitmap_get(data->base, bitmap_pos)) {
obj->flags |= SEEN;
return 0;
}
return 1;
}
static int add_commit_to_bitmap(struct bitmap_index *bitmap_git,
struct bitmap **base,
struct commit *commit)
{
struct ewah_bitmap *or_with = bitmap_for_commit(bitmap_git, commit);
if (!or_with)
return 0;
if (!*base)
*base = ewah_to_bitmap(or_with);
else
bitmap_or_ewah(*base, or_with);
return 1;
}
static struct bitmap *find_objects(struct bitmap_index *bitmap_git,
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 &&
add_commit_to_bitmap(bitmap_git, &base, (struct commit *)object)) {
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)
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(bitmap_git, &object->oid);
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;
struct bitmap_show_data show_data;
if (!base)
base = bitmap_new();
incdata.bitmap_git = bitmap_git;
incdata.base = base;
incdata.seen = seen;
revs->include_check = should_include;
revs->include_check_obj = should_include_obj;
revs->include_check_data = &incdata;
if (prepare_revision_walk(revs))
die(_("revision walk setup failed"));
show_data.bitmap_git = bitmap_git;
show_data.base = base;
traverse_commit_list(revs,
show_commit, show_object,
&show_data);
revs->include_check = NULL;
revs->include_check_obj = NULL;
revs->include_check_data = NULL;
}
return base;
}
static void show_extended_objects(struct bitmap_index *bitmap_git,
struct rev_info *revs,
show_reachable_fn show_reach)
{
struct bitmap *objects = bitmap_git->result;
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_num_objects(bitmap_git) + i))
continue;
obj = eindex->objects[i];
if ((obj->type == OBJ_BLOB && !revs->blob_objects) ||
(obj->type == OBJ_TREE && !revs->tree_objects) ||
(obj->type == OBJ_TAG && !revs->tag_objects))
continue;
show_reach(&obj->oid, obj->type, 0, eindex->hashes[i], NULL, 0);
}
}
static void init_type_iterator(struct ewah_iterator *it,
struct bitmap_index *bitmap_git,
enum object_type type)
{
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:
BUG("object type %d not stored by bitmap type index", type);
break;
}
}
static void show_objects_for_type(
struct bitmap_index *bitmap_git,
enum object_type object_type,
show_reachable_fn show_reach)
{
size_t i = 0;
uint32_t offset;
struct ewah_iterator it;
eword_t filter;
struct bitmap *objects = bitmap_git->result;
init_type_iterator(&it, bitmap_git, object_type);
for (i = 0; i < objects->word_alloc &&
ewah_iterator_next(&filter, &it); i++) {
eword_t word = objects->words[i] & filter;
size_t pos = (i * BITS_IN_EWORD);
if (!word)
continue;
for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
struct packed_git *pack;
struct object_id oid;
uint32_t hash = 0, index_pos;
off_t ofs;
if ((word >> offset) == 0)
break;
offset += ewah_bit_ctz64(word >> offset);
if (bitmap_is_midx(bitmap_git)) {
struct multi_pack_index *m = bitmap_git->midx;
uint32_t pack_id;
index_pos = pack_pos_to_midx(m, pos + offset);
ofs = nth_midxed_offset(m, index_pos);
nth_midxed_object_oid(&oid, m, index_pos);
pack_id = nth_midxed_pack_int_id(m, index_pos);
pack = bitmap_git->midx->packs[pack_id];
} else {
index_pos = pack_pos_to_index(bitmap_git->pack, pos + offset);
ofs = pack_pos_to_offset(bitmap_git->pack, pos + offset);
nth_bitmap_object_oid(bitmap_git, &oid, index_pos);
pack = bitmap_git->pack;
}
if (bitmap_git->hashes)
hash = get_be32(bitmap_git->hashes + index_pos);
show_reach(&oid, object_type, 0, hash, pack, ofs);
}
}
}
static int in_bitmapped_pack(struct bitmap_index *bitmap_git,
struct object_list *roots)
{
while (roots) {
struct object *object = roots->item;
roots = roots->next;
if (bitmap_is_midx(bitmap_git)) {
if (bsearch_midx(&object->oid, bitmap_git->midx, NULL))
return 1;
} else {
if (find_pack_entry_one(object->oid.hash, bitmap_git->pack) > 0)
return 1;
}
}
return 0;
}
static struct bitmap *find_tip_objects(struct bitmap_index *bitmap_git,
struct object_list *tip_objects,
enum object_type type)
{
struct bitmap *result = bitmap_new();
struct object_list *p;
for (p = tip_objects; p; p = p->next) {
int pos;
if (p->item->type != type)
continue;
pos = bitmap_position(bitmap_git, &p->item->oid);
if (pos < 0)
continue;
bitmap_set(result, pos);
}
return result;
}
static void filter_bitmap_exclude_type(struct bitmap_index *bitmap_git,
struct object_list *tip_objects,
struct bitmap *to_filter,
enum object_type type)
{
struct eindex *eindex = &bitmap_git->ext_index;
struct bitmap *tips;
struct ewah_iterator it;
eword_t mask;
uint32_t i;
/*
* The non-bitmap version of this filter never removes
* objects which the other side specifically asked for,
* so we must match that behavior.
*/
tips = find_tip_objects(bitmap_git, tip_objects, type);
/*
* We can use the type-level bitmap for 'type' to work in whole
* words for the objects that are actually in the bitmapped
* packfile.
*/
for (i = 0, init_type_iterator(&it, bitmap_git, type);
i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
i++) {
if (i < tips->word_alloc)
mask &= ~tips->words[i];
to_filter->words[i] &= ~mask;
}
/*
* Clear any objects that weren't in the packfile (and so would
* not have been caught by the loop above. We'll have to check
* them individually.
*/
for (i = 0; i < eindex->count; i++) {
uint32_t pos = i + bitmap_num_objects(bitmap_git);
if (eindex->objects[i]->type == type &&
bitmap_get(to_filter, pos) &&
!bitmap_get(tips, pos))
bitmap_unset(to_filter, pos);
}
bitmap_free(tips);
}
static void filter_bitmap_blob_none(struct bitmap_index *bitmap_git,
struct object_list *tip_objects,
struct bitmap *to_filter)
{
filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
OBJ_BLOB);
}
static unsigned long get_size_by_pos(struct bitmap_index *bitmap_git,
uint32_t pos)
{
unsigned long size;
struct object_info oi = OBJECT_INFO_INIT;
oi.sizep = &size;
if (pos < bitmap_num_objects(bitmap_git)) {
struct packed_git *pack;
off_t ofs;
if (bitmap_is_midx(bitmap_git)) {
uint32_t midx_pos = pack_pos_to_midx(bitmap_git->midx, pos);
uint32_t pack_id = nth_midxed_pack_int_id(bitmap_git->midx, midx_pos);
pack = bitmap_git->midx->packs[pack_id];
ofs = nth_midxed_offset(bitmap_git->midx, midx_pos);
} else {
pack = bitmap_git->pack;
ofs = pack_pos_to_offset(pack, pos);
}
if (packed_object_info(the_repository, pack, ofs, &oi) < 0) {
struct object_id oid;
nth_bitmap_object_oid(bitmap_git, &oid,
pack_pos_to_index(pack, pos));
die(_("unable to get size of %s"), oid_to_hex(&oid));
}
} else {
struct eindex *eindex = &bitmap_git->ext_index;
struct object *obj = eindex->objects[pos - bitmap_num_objects(bitmap_git)];
if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
die(_("unable to get size of %s"), oid_to_hex(&obj->oid));
}
return size;
}
static void filter_bitmap_blob_limit(struct bitmap_index *bitmap_git,
struct object_list *tip_objects,
struct bitmap *to_filter,
unsigned long limit)
{
struct eindex *eindex = &bitmap_git->ext_index;
struct bitmap *tips;
struct ewah_iterator it;
eword_t mask;
uint32_t i;
tips = find_tip_objects(bitmap_git, tip_objects, OBJ_BLOB);
for (i = 0, init_type_iterator(&it, bitmap_git, OBJ_BLOB);
i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
i++) {
eword_t word = to_filter->words[i] & mask;
unsigned offset;
for (offset = 0; offset < BITS_IN_EWORD; offset++) {
uint32_t pos;
if ((word >> offset) == 0)
break;
offset += ewah_bit_ctz64(word >> offset);
pos = i * BITS_IN_EWORD + offset;
if (!bitmap_get(tips, pos) &&
get_size_by_pos(bitmap_git, pos) >= limit)
bitmap_unset(to_filter, pos);
}
}
for (i = 0; i < eindex->count; i++) {
uint32_t pos = i + bitmap_num_objects(bitmap_git);
if (eindex->objects[i]->type == OBJ_BLOB &&
bitmap_get(to_filter, pos) &&
!bitmap_get(tips, pos) &&
get_size_by_pos(bitmap_git, pos) >= limit)
bitmap_unset(to_filter, pos);
}
bitmap_free(tips);
}
static void filter_bitmap_tree_depth(struct bitmap_index *bitmap_git,
struct object_list *tip_objects,
struct bitmap *to_filter,
unsigned long limit)
{
if (limit)
BUG("filter_bitmap_tree_depth given non-zero limit");
filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
OBJ_TREE);
filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
OBJ_BLOB);
}
static void filter_bitmap_object_type(struct bitmap_index *bitmap_git,
struct object_list *tip_objects,
struct bitmap *to_filter,
enum object_type object_type)
{
if (object_type < OBJ_COMMIT || object_type > OBJ_TAG)
BUG("filter_bitmap_object_type given invalid object");
if (object_type != OBJ_TAG)
filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter, OBJ_TAG);
if (object_type != OBJ_COMMIT)
filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter, OBJ_COMMIT);
if (object_type != OBJ_TREE)
filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter, OBJ_TREE);
if (object_type != OBJ_BLOB)
filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter, OBJ_BLOB);
}
static int filter_bitmap(struct bitmap_index *bitmap_git,
struct object_list *tip_objects,
struct bitmap *to_filter,
struct list_objects_filter_options *filter)
{
if (!filter || filter->choice == LOFC_DISABLED)
return 0;
if (filter->choice == LOFC_BLOB_NONE) {
if (bitmap_git)
filter_bitmap_blob_none(bitmap_git, tip_objects,
to_filter);
return 0;
}
if (filter->choice == LOFC_BLOB_LIMIT) {
if (bitmap_git)
filter_bitmap_blob_limit(bitmap_git, tip_objects,
to_filter,
filter->blob_limit_value);
return 0;
}
if (filter->choice == LOFC_TREE_DEPTH &&
filter->tree_exclude_depth == 0) {
if (bitmap_git)
filter_bitmap_tree_depth(bitmap_git, tip_objects,
to_filter,
filter->tree_exclude_depth);
return 0;
}
if (filter->choice == LOFC_OBJECT_TYPE) {
if (bitmap_git)
filter_bitmap_object_type(bitmap_git, tip_objects,
to_filter,
filter->object_type);
return 0;
}
if (filter->choice == LOFC_COMBINE) {
int i;
for (i = 0; i < filter->sub_nr; i++) {
if (filter_bitmap(bitmap_git, tip_objects, to_filter,
&filter->sub[i]) < 0)
return -1;
}
return 0;
}
/* filter choice not handled */
return -1;
}
static int can_filter_bitmap(struct list_objects_filter_options *filter)
{
return !filter_bitmap(NULL, NULL, NULL, filter);
}
struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs,
int filter_provided_objects)
{
unsigned int i;
struct object_list *wants = NULL;
struct object_list *haves = NULL;
struct bitmap *wants_bitmap = NULL;
struct bitmap *haves_bitmap = NULL;
struct bitmap_index *bitmap_git;
/*
* We can't do pathspec limiting with bitmaps, because we don't know
* which commits are associated with which object changes (let alone
* even which objects are associated with which paths).
*/
if (revs->prune)
return NULL;
if (!can_filter_bitmap(&revs->filter))
return NULL;
/* try to open a bitmapped pack, but don't parse it yet
* because we may not need to use it */
CALLOC_ARRAY(bitmap_git, 1);
if (open_bitmap(revs->repo, bitmap_git) < 0)
goto cleanup;
for (i = 0; i < revs->pending.nr; ++i) {
struct object *object = revs->pending.objects[i].item;
if (object->type == OBJ_NONE)
parse_object_or_die(&object->oid, 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);
object = parse_object_or_die(get_tagged_oid(tag), NULL);
object->flags |= (tag->object.flags & UNINTERESTING);
}
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(bitmap_git, haves))
goto cleanup;
/* if we don't want anything, we're done here */
if (!wants)
goto cleanup;
/*
* 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 (load_bitmap(revs->repo, bitmap_git) < 0)
goto cleanup;
object_array_clear(&revs->pending);
if (haves) {
revs->ignore_missing_links = 1;
haves_bitmap = find_objects(bitmap_git, revs, haves, NULL);
reset_revision_walk();
revs->ignore_missing_links = 0;
if (!haves_bitmap)
BUG("failed to perform bitmap walk");
}
wants_bitmap = find_objects(bitmap_git, revs, wants, haves_bitmap);
if (!wants_bitmap)
BUG("failed to perform bitmap walk");
if (haves_bitmap)
bitmap_and_not(wants_bitmap, haves_bitmap);
filter_bitmap(bitmap_git,
(revs->filter.choice && filter_provided_objects) ? NULL : wants,
wants_bitmap,
&revs->filter);
bitmap_git->result = wants_bitmap;
bitmap_git->haves = haves_bitmap;
object_list_free(&wants);
object_list_free(&haves);
return bitmap_git;
cleanup:
free_bitmap_index(bitmap_git);
object_list_free(&wants);
object_list_free(&haves);
return NULL;
}
/*
* -1 means "stop trying further objects"; 0 means we may or may not have
* reused, but you can keep feeding bits.
*/
static int try_partial_reuse(struct packed_git *pack,
size_t pos,
struct bitmap *reuse,
struct pack_window **w_curs)
{
off_t offset, delta_obj_offset;
enum object_type type;
unsigned long size;
/*
* try_partial_reuse() is called either on (a) objects in the
* bitmapped pack (in the case of a single-pack bitmap) or (b)
* objects in the preferred pack of a multi-pack bitmap.
* Importantly, the latter can pretend as if only a single pack
* exists because:
*
* - The first pack->num_objects bits of a MIDX bitmap are
* reserved for the preferred pack, and
*
* - Ties due to duplicate objects are always resolved in
* favor of the preferred pack.
*
* Therefore we do not need to ever ask the MIDX for its copy of
* an object by OID, since it will always select it from the
* preferred pack. Likewise, the selected copy of the base
* object for any deltas will reside in the same pack.
*
* This means that we can reuse pos when looking up the bit in
* the reuse bitmap, too, since bits corresponding to the
* preferred pack precede all bits from other packs.
*/
if (pos >= pack->num_objects)
return -1; /* not actually in the pack or MIDX preferred pack */
offset = delta_obj_offset = pack_pos_to_offset(pack, pos);
type = unpack_object_header(pack, w_curs, &offset, &size);
if (type < 0)
return -1; /* broken packfile, punt */
if (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA) {
off_t base_offset;
uint32_t base_pos;
/*
* Find the position of the base object so we can look it up
* in our bitmaps. If we can't come up with an offset, or if
* that offset is not in the revidx, the pack is corrupt.
* There's nothing we can do, so just punt on this object,
* and the normal slow path will complain about it in
* more detail.
*/
base_offset = get_delta_base(pack, w_curs, &offset, type,
delta_obj_offset);
if (!base_offset)
return 0;
if (offset_to_pack_pos(pack, base_offset, &base_pos) < 0)
return 0;
/*
* We assume delta dependencies always point backwards. This
* lets us do a single pass, and is basically always true
* due to the way OFS_DELTAs work. You would not typically
* find REF_DELTA in a bitmapped pack, since we only bitmap
* packs we write fresh, and OFS_DELTA is the default). But
* let's double check to make sure the pack wasn't written with
* odd parameters.
*/
if (base_pos >= pos)
return 0;
/*
* And finally, if we're not sending the base as part of our
* reuse chunk, then don't send this object either. The base
* would come after us, along with other objects not
* necessarily in the pack, which means we'd need to convert
* to REF_DELTA on the fly. Better to just let the normal
* object_entry code path handle it.
*/
if (!bitmap_get(reuse, base_pos))
return 0;
}
/*
* If we got here, then the object is OK to reuse. Mark it.
*/
bitmap_set(reuse, pos);
return 0;
}
uint32_t midx_preferred_pack(struct bitmap_index *bitmap_git)
{
struct multi_pack_index *m = bitmap_git->midx;
if (!m)
BUG("midx_preferred_pack: requires non-empty MIDX");
return nth_midxed_pack_int_id(m, pack_pos_to_midx(bitmap_git->midx, 0));
}
int reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
struct packed_git **packfile_out,
uint32_t *entries,
struct bitmap **reuse_out)
{
struct repository *r = the_repository;
struct packed_git *pack;
struct bitmap *result = bitmap_git->result;
struct bitmap *reuse;
struct pack_window *w_curs = NULL;
size_t i = 0;
uint32_t offset;
uint32_t objects_nr;
assert(result);
load_reverse_index(r, bitmap_git);
if (bitmap_is_midx(bitmap_git))
pack = bitmap_git->midx->packs[midx_preferred_pack(bitmap_git)];
else
pack = bitmap_git->pack;
objects_nr = pack->num_objects;
while (i < result->word_alloc && result->words[i] == (eword_t)~0)
i++;
/*
* Don't mark objects not in the packfile or preferred pack. This bitmap
* marks objects eligible for reuse, but the pack-reuse code only
* understands how to reuse a single pack. Since the preferred pack is
* guaranteed to have all bases for its deltas (in a multi-pack bitmap),
* we use it instead of another pack. In single-pack bitmaps, the choice
* is made for us.
*/
if (i > objects_nr / BITS_IN_EWORD)
i = objects_nr / BITS_IN_EWORD;
reuse = bitmap_word_alloc(i);
memset(reuse->words, 0xFF, i * sizeof(eword_t));
for (; i < result->word_alloc; ++i) {
eword_t word = result->words[i];
size_t pos = (i * BITS_IN_EWORD);
for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
if ((word >> offset) == 0)
break;
offset += ewah_bit_ctz64(word >> offset);
if (try_partial_reuse(pack, pos + offset,
reuse, &w_curs) < 0) {
/*
* try_partial_reuse indicated we couldn't reuse
* any bits, so there is no point in trying more
* bits in the current word, or any other words
* in result.
*
* Jump out of both loops to avoid future
* unnecessary calls to try_partial_reuse.
*/
goto done;
}
}
}
done:
unuse_pack(&w_curs);
*entries = bitmap_popcount(reuse);
if (!*entries) {
bitmap_free(reuse);
return -1;
}
/*
* Drop any reused objects from the result, since they will not
* need to be handled separately.
*/
bitmap_and_not(result, reuse);
*packfile_out = pack;
*reuse_out = reuse;
return 0;
}
int bitmap_walk_contains(struct bitmap_index *bitmap_git,
struct bitmap *bitmap, const struct object_id *oid)
{
int idx;
if (!bitmap)
return 0;
idx = bitmap_position(bitmap_git, oid);
return idx >= 0 && bitmap_get(bitmap, idx);
}
void traverse_bitmap_commit_list(struct bitmap_index *bitmap_git,
struct rev_info *revs,
show_reachable_fn show_reachable)
{
assert(bitmap_git->result);
show_objects_for_type(bitmap_git, OBJ_COMMIT, show_reachable);
if (revs->tree_objects)
show_objects_for_type(bitmap_git, OBJ_TREE, show_reachable);
if (revs->blob_objects)
show_objects_for_type(bitmap_git, OBJ_BLOB, show_reachable);
if (revs->tag_objects)
show_objects_for_type(bitmap_git, OBJ_TAG, show_reachable);
show_extended_objects(bitmap_git, revs, show_reachable);
}
static uint32_t count_object_type(struct bitmap_index *bitmap_git,
enum object_type type)
{
struct bitmap *objects = bitmap_git->result;
struct eindex *eindex = &bitmap_git->ext_index;
uint32_t i = 0, count = 0;
struct ewah_iterator it;
eword_t filter;
init_type_iterator(&it, bitmap_git, type);
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_num_objects(bitmap_git) + i))
count++;
}
return count;
}
void count_bitmap_commit_list(struct bitmap_index *bitmap_git,
uint32_t *commits, uint32_t *trees,
uint32_t *blobs, uint32_t *tags)
{
assert(bitmap_git->result);
if (commits)
*commits = count_object_type(bitmap_git, OBJ_COMMIT);
if (trees)
*trees = count_object_type(bitmap_git, OBJ_TREE);
if (blobs)
*blobs = count_object_type(bitmap_git, OBJ_BLOB);
if (tags)
*tags = count_object_type(bitmap_git, OBJ_TAG);
}
struct bitmap_test_data {
struct bitmap_index *bitmap_git;
struct bitmap *base;
struct bitmap *commits;
struct bitmap *trees;
struct bitmap *blobs;
struct bitmap *tags;
struct progress *prg;
size_t seen;
};
static void test_bitmap_type(struct bitmap_test_data *tdata,
struct object *obj, int pos)
{
enum object_type bitmap_type = OBJ_NONE;
int bitmaps_nr = 0;
if (bitmap_get(tdata->commits, pos)) {
bitmap_type = OBJ_COMMIT;
bitmaps_nr++;
}
if (bitmap_get(tdata->trees, pos)) {
bitmap_type = OBJ_TREE;
bitmaps_nr++;
}
if (bitmap_get(tdata->blobs, pos)) {
bitmap_type = OBJ_BLOB;
bitmaps_nr++;
}
if (bitmap_get(tdata->tags, pos)) {
bitmap_type = OBJ_TAG;
bitmaps_nr++;
}
if (bitmap_type == OBJ_NONE)
die(_("object '%s' not found in type bitmaps"),
oid_to_hex(&obj->oid));
if (bitmaps_nr > 1)
die(_("object '%s' does not have a unique type"),
oid_to_hex(&obj->oid));
if (bitmap_type != obj->type)
die(_("object '%s': real type '%s', expected: '%s'"),
oid_to_hex(&obj->oid),
type_name(obj->type),
type_name(bitmap_type));
}
static void test_show_object(struct object *object,
const char *name UNUSED,
void *data)
{
struct bitmap_test_data *tdata = data;
int bitmap_pos;
bitmap_pos = bitmap_position(tdata->bitmap_git, &object->oid);
if (bitmap_pos < 0)
die(_("object not in bitmap: '%s'"), oid_to_hex(&object->oid));
test_bitmap_type(tdata, object, bitmap_pos);
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(tdata->bitmap_git,
&commit->object.oid);
if (bitmap_pos < 0)
die(_("object not in bitmap: '%s'"), oid_to_hex(&commit->object.oid));
test_bitmap_type(tdata, &commit->object, bitmap_pos);
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;
size_t result_popcnt;
struct bitmap_test_data tdata;
struct bitmap_index *bitmap_git;
struct ewah_bitmap *bm;
if (!(bitmap_git = prepare_bitmap_git(revs->repo)))
die(_("failed to load bitmap indexes"));
if (revs->pending.nr != 1)
die(_("you must specify exactly one commit to test"));
fprintf_ln(stderr, "Bitmap v%d test (%d entries%s)",
bitmap_git->version,
bitmap_git->entry_count,
bitmap_git->table_lookup ? "" : " loaded");
root = revs->pending.objects[0].item;
bm = bitmap_for_commit(bitmap_git, (struct commit *)root);
if (bm) {
fprintf_ln(stderr, "Found bitmap for '%s'. %d bits / %08x checksum",
oid_to_hex(&root->oid), (int)bm->bit_size, ewah_checksum(bm));
result = ewah_to_bitmap(bm);
}
if (!result)
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.bitmap_git = bitmap_git;
tdata.base = bitmap_new();
tdata.commits = ewah_to_bitmap(bitmap_git->commits);
tdata.trees = ewah_to_bitmap(bitmap_git->trees);
tdata.blobs = ewah_to_bitmap(bitmap_git->blobs);
tdata.tags = ewah_to_bitmap(bitmap_git->tags);
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_ln(stderr, "OK!");
else
die(_("mismatch in bitmap results"));
bitmap_free(result);
bitmap_free(tdata.base);
bitmap_free(tdata.commits);
bitmap_free(tdata.trees);
bitmap_free(tdata.blobs);
bitmap_free(tdata.tags);
free_bitmap_index(bitmap_git);
}
int test_bitmap_commits(struct repository *r)
{
struct object_id oid;
MAYBE_UNUSED void *value;
struct bitmap_index *bitmap_git = prepare_bitmap_git(r);
if (!bitmap_git)
die(_("failed to load bitmap indexes"));
/*
* As this function is only used to print bitmap selected
* commits, we don't have to read the commit table.
*/
if (bitmap_git->table_lookup) {
if (load_bitmap_entries_v1(bitmap_git) < 0)
die(_("failed to load bitmap indexes"));
}
kh_foreach(bitmap_git->bitmaps, oid, value, {
printf_ln("%s", oid_to_hex(&oid));
});
free_bitmap_index(bitmap_git);
return 0;
}
int test_bitmap_hashes(struct repository *r)
{
struct bitmap_index *bitmap_git = prepare_bitmap_git(r);
struct object_id oid;
uint32_t i, index_pos;
if (!bitmap_git || !bitmap_git->hashes)
goto cleanup;
for (i = 0; i < bitmap_num_objects(bitmap_git); i++) {
if (bitmap_is_midx(bitmap_git))
index_pos = pack_pos_to_midx(bitmap_git->midx, i);
else
index_pos = pack_pos_to_index(bitmap_git->pack, i);
nth_bitmap_object_oid(bitmap_git, &oid, index_pos);
printf_ln("%s %"PRIu32"",
oid_to_hex(&oid), get_be32(bitmap_git->hashes + index_pos));
}
cleanup:
free_bitmap_index(bitmap_git);
return 0;
}
int rebuild_bitmap(const 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;
}
uint32_t *create_bitmap_mapping(struct bitmap_index *bitmap_git,
struct packing_data *mapping)
{
struct repository *r = the_repository;
uint32_t i, num_objects;
uint32_t *reposition;
if (!bitmap_is_midx(bitmap_git))
load_reverse_index(r, bitmap_git);
else if (load_midx_revindex(bitmap_git->midx))
BUG("rebuild_existing_bitmaps: missing required rev-cache "
"extension");
num_objects = bitmap_num_objects(bitmap_git);
CALLOC_ARRAY(reposition, num_objects);
for (i = 0; i < num_objects; ++i) {
struct object_id oid;
struct object_entry *oe;
uint32_t index_pos;
if (bitmap_is_midx(bitmap_git))
index_pos = pack_pos_to_midx(bitmap_git->midx, i);
else
index_pos = pack_pos_to_index(bitmap_git->pack, i);
nth_bitmap_object_oid(bitmap_git, &oid, index_pos);
oe = packlist_find(mapping, &oid);
if (oe) {
reposition[i] = oe_in_pack_pos(mapping, oe) + 1;
if (bitmap_git->hashes && !oe->hash)
oe->hash = get_be32(bitmap_git->hashes + index_pos);
}
}
return reposition;
}
void free_bitmap_index(struct bitmap_index *b)
{
if (!b)
return;
if (b->map)
munmap(b->map, b->map_size);
ewah_pool_free(b->commits);
ewah_pool_free(b->trees);
ewah_pool_free(b->blobs);
ewah_pool_free(b->tags);
if (b->bitmaps) {
struct stored_bitmap *sb;
kh_foreach_value(b->bitmaps, sb, {
ewah_pool_free(sb->root);
free(sb);
});
}
kh_destroy_oid_map(b->bitmaps);
free(b->ext_index.objects);
free(b->ext_index.hashes);
kh_destroy_oid_pos(b->ext_index.positions);
bitmap_free(b->result);
bitmap_free(b->haves);
if (bitmap_is_midx(b)) {
/*
* Multi-pack bitmaps need to have resources associated with
* their on-disk reverse indexes unmapped so that stale .rev and
* .bitmap files can be removed.
*
* Unlike pack-based bitmaps, multi-pack bitmaps can be read and
* written in the same 'git multi-pack-index write --bitmap'
* process. Close resources so they can be removed safely on
* platforms like Windows.
*/
close_midx_revindex(b->midx);
}
free(b);
}
int bitmap_has_oid_in_uninteresting(struct bitmap_index *bitmap_git,
const struct object_id *oid)
{
return bitmap_git &&
bitmap_walk_contains(bitmap_git, bitmap_git->haves, oid);
}
static off_t get_disk_usage_for_type(struct bitmap_index *bitmap_git,
enum object_type object_type)
{
struct bitmap *result = bitmap_git->result;
off_t total = 0;
struct ewah_iterator it;
eword_t filter;
size_t i;
init_type_iterator(&it, bitmap_git, object_type);
for (i = 0; i < result->word_alloc &&
ewah_iterator_next(&filter, &it); i++) {
eword_t word = result->words[i] & filter;
size_t base = (i * BITS_IN_EWORD);
unsigned offset;
if (!word)
continue;
for (offset = 0; offset < BITS_IN_EWORD; offset++) {
if ((word >> offset) == 0)
break;
offset += ewah_bit_ctz64(word >> offset);
if (bitmap_is_midx(bitmap_git)) {
uint32_t pack_pos;
uint32_t midx_pos = pack_pos_to_midx(bitmap_git->midx, base + offset);
off_t offset = nth_midxed_offset(bitmap_git->midx, midx_pos);
uint32_t pack_id = nth_midxed_pack_int_id(bitmap_git->midx, midx_pos);
struct packed_git *pack = bitmap_git->midx->packs[pack_id];
if (offset_to_pack_pos(pack, offset, &pack_pos) < 0) {
struct object_id oid;
nth_midxed_object_oid(&oid, bitmap_git->midx, midx_pos);
die(_("could not find '%s' in pack '%s' at offset %"PRIuMAX),
oid_to_hex(&oid),
pack->pack_name,
(uintmax_t)offset);
}
total += pack_pos_to_offset(pack, pack_pos + 1) - offset;
} else {
size_t pos = base + offset;
total += pack_pos_to_offset(bitmap_git->pack, pos + 1) -
pack_pos_to_offset(bitmap_git->pack, pos);
}
}
}
return total;
}
static off_t get_disk_usage_for_extended(struct bitmap_index *bitmap_git)
{
struct bitmap *result = bitmap_git->result;
struct eindex *eindex = &bitmap_git->ext_index;
off_t total = 0;
struct object_info oi = OBJECT_INFO_INIT;
off_t object_size;
size_t i;
oi.disk_sizep = &object_size;
for (i = 0; i < eindex->count; i++) {
struct object *obj = eindex->objects[i];
if (!bitmap_get(result, bitmap_num_objects(bitmap_git) + i))
continue;
if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
die(_("unable to get disk usage of '%s'"),
oid_to_hex(&obj->oid));
total += object_size;
}
return total;
}
off_t get_disk_usage_from_bitmap(struct bitmap_index *bitmap_git,
struct rev_info *revs)
{
off_t total = 0;
total += get_disk_usage_for_type(bitmap_git, OBJ_COMMIT);
if (revs->tree_objects)
total += get_disk_usage_for_type(bitmap_git, OBJ_TREE);
if (revs->blob_objects)
total += get_disk_usage_for_type(bitmap_git, OBJ_BLOB);
if (revs->tag_objects)
total += get_disk_usage_for_type(bitmap_git, OBJ_TAG);
total += get_disk_usage_for_extended(bitmap_git);
return total;
}
int bitmap_is_midx(struct bitmap_index *bitmap_git)
{
return !!bitmap_git->midx;
}
const struct string_list *bitmap_preferred_tips(struct repository *r)
{
const struct string_list *dest;
if (!repo_config_get_string_multi(r, "pack.preferbitmaptips", &dest))
return dest;
return NULL;
}
int bitmap_is_preferred_refname(struct repository *r, const char *refname)
{
const struct string_list *preferred_tips = bitmap_preferred_tips(r);
struct string_list_item *item;
if (!preferred_tips)
return 0;
for_each_string_list_item(item, preferred_tips) {
if (starts_with(refname, item->string))
return 1;
}
return 0;
}
static int verify_bitmap_file(const char *name)
{
struct stat st;
unsigned char *data;
int fd = git_open(name);
int res = 0;
/* It is OK to not have the file. */
if (fd < 0 || fstat(fd, &st)) {
if (fd >= 0)
close(fd);
return 0;
}
data = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (!hashfile_checksum_valid(data, st.st_size))
res = error(_("bitmap file '%s' has invalid checksum"),
name);
munmap(data, st.st_size);
return res;
}
int verify_bitmap_files(struct repository *r)
{
int res = 0;
for (struct multi_pack_index *m = get_multi_pack_index(r);
m; m = m->next) {
char *midx_bitmap_name = midx_bitmap_filename(m);
res |= verify_bitmap_file(midx_bitmap_name);
free(midx_bitmap_name);
}
for (struct packed_git *p = get_all_packs(r);
p; p = p->next) {
char *pack_bitmap_name = pack_bitmap_filename(p);
res |= verify_bitmap_file(pack_bitmap_name);
free(pack_bitmap_name);
}
return res;
}