/*
* Copyright (C) the libgit2 contributors. All rights reserved.
*
* This file is part of libgit2, distributed under the GNU GPL v2 with
* a Linking Exception. For full terms see the included COPYING file.
*/
#include "pack-objects.h"
#include "compress.h"
#include "delta.h"
#include "iterator.h"
#include "netops.h"
#include "pack.h"
#include "thread-utils.h"
#include "tree.h"
#include "git2/pack.h"
#include "git2/commit.h"
#include "git2/tag.h"
#include "git2/indexer.h"
#include "git2/config.h"
struct unpacked {
git_pobject *object;
void *data;
struct git_delta_index *index;
unsigned int depth;
};
struct tree_walk_context {
git_packbuilder *pb;
git_buf buf;
};
#ifdef GIT_THREADS
#define GIT_PACKBUILDER__MUTEX_OP(pb, mtx, op) do { \
int result = git_mutex_##op(&(pb)->mtx); \
assert(!result); \
GIT_UNUSED(result); \
} while (0)
#else
#define GIT_PACKBUILDER__MUTEX_OP(pb,mtx,op) GIT_UNUSED(pb)
#endif /* GIT_THREADS */
#define git_packbuilder__cache_lock(pb) GIT_PACKBUILDER__MUTEX_OP(pb, cache_mutex, lock)
#define git_packbuilder__cache_unlock(pb) GIT_PACKBUILDER__MUTEX_OP(pb, cache_mutex, unlock)
#define git_packbuilder__progress_lock(pb) GIT_PACKBUILDER__MUTEX_OP(pb, progress_mutex, lock)
#define git_packbuilder__progress_unlock(pb) GIT_PACKBUILDER__MUTEX_OP(pb, progress_mutex, unlock)
static unsigned name_hash(const char *name)
{
unsigned c, hash = 0;
if (!name)
return 0;
/*
* This effectively just creates a sortable number from the
* last sixteen non-whitespace characters. Last characters
* count "most", so things that end in ".c" sort together.
*/
while ((c = *name++) != 0) {
if (git__isspace(c))
continue;
hash = (hash >> 2) + (c << 24);
}
return hash;
}
static int packbuilder_config(git_packbuilder *pb)
{
git_config *config;
int ret;
int64_t val;
if (git_repository_config__weakptr(&config, pb->repo) < 0)
return -1;
#define config_get(KEY,DST,DFLT) do { \
ret = git_config_get_int64(&val, config, KEY); \
if (!ret) (DST) = val; \
else if (ret == GIT_ENOTFOUND) (DST) = (DFLT); \
else if (ret < 0) return -1; } while (0)
config_get("pack.deltaCacheSize", pb->max_delta_cache_size,
GIT_PACK_DELTA_CACHE_SIZE);
config_get("pack.deltaCacheLimit", pb->cache_max_small_delta_size,
GIT_PACK_DELTA_CACHE_LIMIT);
config_get("pack.deltaCacheSize", pb->big_file_threshold,
GIT_PACK_BIG_FILE_THRESHOLD);
config_get("pack.windowMemory", pb->window_memory_limit, 0);
#undef config_get
return 0;
}
int git_packbuilder_new(git_packbuilder **out, git_repository *repo)
{
git_packbuilder *pb;
*out = NULL;
pb = git__calloc(1, sizeof(*pb));
GITERR_CHECK_ALLOC(pb);
pb->object_ix = git_oidmap_alloc();
if (!pb->object_ix)
goto on_error;
pb->repo = repo;
pb->nr_threads = 1; /* do not spawn any thread by default */
if (git_hash_ctx_init(&pb->ctx) < 0 ||
git_repository_odb(&pb->odb, repo) < 0 ||
packbuilder_config(pb) < 0)
goto on_error;
#ifdef GIT_THREADS
if (git_mutex_init(&pb->cache_mutex) ||
git_mutex_init(&pb->progress_mutex) ||
git_cond_init(&pb->progress_cond))
goto on_error;
#endif
*out = pb;
return 0;
on_error:
git_packbuilder_free(pb);
return -1;
}
unsigned int git_packbuilder_set_threads(git_packbuilder *pb, unsigned int n)
{
assert(pb);
#ifdef GIT_THREADS
pb->nr_threads = n;
#else
GIT_UNUSED(n);
assert(1 == pb->nr_threads);
#endif
return pb->nr_threads;
}
static void rehash(git_packbuilder *pb)
{
git_pobject *po;
khiter_t pos;
unsigned int i;
int ret;
kh_clear(oid, pb->object_ix);
for (i = 0, po = pb->object_list; i < pb->nr_objects; i++, po++) {
pos = kh_put(oid, pb->object_ix, &po->id, &ret);
kh_value(pb->object_ix, pos) = po;
}
}
int git_packbuilder_insert(git_packbuilder *pb, const git_oid *oid,
const char *name)
{
git_pobject *po;
khiter_t pos;
int ret;
assert(pb && oid);
/* If the object already exists in the hash table, then we don't
* have any work to do */
pos = kh_get(oid, pb->object_ix, oid);
if (pos != kh_end(pb->object_ix))
return 0;
if (pb->nr_objects >= pb->nr_alloc) {
pb->nr_alloc = (pb->nr_alloc + 1024) * 3 / 2;
pb->object_list = git__realloc(pb->object_list,
pb->nr_alloc * sizeof(*po));
GITERR_CHECK_ALLOC(pb->object_list);
rehash(pb);
}
po = pb->object_list + pb->nr_objects;
memset(po, 0x0, sizeof(*po));
if (git_odb_read_header(&po->size, &po->type, pb->odb, oid) < 0)
return -1;
pb->nr_objects++;
git_oid_cpy(&po->id, oid);
po->hash = name_hash(name);
pos = kh_put(oid, pb->object_ix, &po->id, &ret);
assert(ret != 0);
kh_value(pb->object_ix, pos) = po;
pb->done = false;
return 0;
}
/*
* The per-object header is a pretty dense thing, which is
* - first byte: low four bits are "size",
* then three bits of "type",
* with the high bit being "size continues".
* - each byte afterwards: low seven bits are size continuation,
* with the high bit being "size continues"
*/
static int gen_pack_object_header(
unsigned char *hdr,
unsigned long size,
git_otype type)
{
unsigned char *hdr_base;
unsigned char c;
assert(type >= GIT_OBJ_COMMIT && type <= GIT_OBJ_REF_DELTA);
/* TODO: add support for chunked objects; see git.git 6c0d19b1 */
c = (unsigned char)((type << 4) | (size & 15));
size >>= 4;
hdr_base = hdr;
while (size) {
*hdr++ = c | 0x80;
c = size & 0x7f;
size >>= 7;
}
*hdr++ = c;
return (int)(hdr - hdr_base);
}
static int get_delta(void **out, git_odb *odb, git_pobject *po)
{
git_odb_object *src = NULL, *trg = NULL;
unsigned long delta_size;
void *delta_buf;
*out = NULL;
if (git_odb_read(&src, odb, &po->delta->id) < 0 ||
git_odb_read(&trg, odb, &po->id) < 0)
goto on_error;
delta_buf = git_delta(
git_odb_object_data(src), (unsigned long)git_odb_object_size(src),
git_odb_object_data(trg), (unsigned long)git_odb_object_size(trg),
&delta_size, 0);
if (!delta_buf || delta_size != po->delta_size) {
giterr_set(GITERR_INVALID, "Delta size changed");
goto on_error;
}
*out = delta_buf;
git_odb_object_free(src);
git_odb_object_free(trg);
return 0;
on_error:
git_odb_object_free(src);
git_odb_object_free(trg);
return -1;
}
static int write_object(git_buf *buf, git_packbuilder *pb, git_pobject *po)
{
git_odb_object *obj = NULL;
git_buf zbuf = GIT_BUF_INIT;
git_otype type;
unsigned char hdr[10];
unsigned int hdr_len;
unsigned long size;
void *data;
if (po->delta) {
if (po->delta_data)
data = po->delta_data;
else if (get_delta(&data, pb->odb, po) < 0)
goto on_error;
size = po->delta_size;
type = GIT_OBJ_REF_DELTA;
} else {
if (git_odb_read(&obj, pb->odb, &po->id))
goto on_error;
data = (void *)git_odb_object_data(obj);
size = (unsigned long)git_odb_object_size(obj);
type = git_odb_object_type(obj);
}
/* Write header */
hdr_len = gen_pack_object_header(hdr, size, type);
if (git_buf_put(buf, (char *)hdr, hdr_len) < 0)
goto on_error;
if (git_hash_update(&pb->ctx, hdr, hdr_len) < 0)
goto on_error;
if (type == GIT_OBJ_REF_DELTA) {
if (git_buf_put(buf, (char *)po->delta->id.id, GIT_OID_RAWSZ) < 0 ||
git_hash_update(&pb->ctx, po->delta->id.id, GIT_OID_RAWSZ) < 0)
goto on_error;
}
/* Write data */
if (po->z_delta_size)
size = po->z_delta_size;
else if (git__compress(&zbuf, data, size) < 0)
goto on_error;
else {
if (po->delta)
git__free(data);
data = zbuf.ptr;
size = (unsigned long)zbuf.size;
}
if (git_buf_put(buf, data, size) < 0 ||
git_hash_update(&pb->ctx, data, size) < 0)
goto on_error;
if (po->delta_data)
git__free(po->delta_data);
git_odb_object_free(obj);
git_buf_free(&zbuf);
pb->nr_written++;
return 0;
on_error:
git_odb_object_free(obj);
git_buf_free(&zbuf);
return -1;
}
enum write_one_status {
WRITE_ONE_SKIP = -1, /* already written */
WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
WRITE_ONE_WRITTEN = 1, /* normal */
WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
};
static int write_one(git_buf *buf, git_packbuilder *pb, git_pobject *po,
enum write_one_status *status)
{
if (po->recursing) {
*status = WRITE_ONE_RECURSIVE;
return 0;
} else if (po->written) {
*status = WRITE_ONE_SKIP;
return 0;
}
if (po->delta) {
po->recursing = 1;
if (write_one(buf, pb, po->delta, status) < 0)
return -1;
switch (*status) {
case WRITE_ONE_RECURSIVE:
/* we cannot depend on this one */
po->delta = NULL;
break;
default:
break;
}
}
po->written = 1;
po->recursing = 0;
return write_object(buf, pb, po);
}
GIT_INLINE(void) add_to_write_order(git_pobject **wo, unsigned int *endp,
git_pobject *po)
{
if (po->filled)
return;
wo[(*endp)++] = po;
po->filled = 1;
}
static void add_descendants_to_write_order(git_pobject **wo, unsigned int *endp,
git_pobject *po)
{
int add_to_order = 1;
while (po) {
if (add_to_order) {
git_pobject *s;
/* add this node... */
add_to_write_order(wo, endp, po);
/* all its siblings... */
for (s = po->delta_sibling; s; s = s->delta_sibling) {
add_to_write_order(wo, endp, s);
}
}
/* drop down a level to add left subtree nodes if possible */
if (po->delta_child) {
add_to_order = 1;
po = po->delta_child;
} else {
add_to_order = 0;
/* our sibling might have some children, it is next */
if (po->delta_sibling) {
po = po->delta_sibling;
continue;
}
/* go back to our parent node */
po = po->delta;
while (po && !po->delta_sibling) {
/* we're on the right side of a subtree, keep
* going up until we can go right again */
po = po->delta;
}
if (!po) {
/* done- we hit our original root node */
return;
}
/* pass it off to sibling at this level */
po = po->delta_sibling;
}
};
}
static void add_family_to_write_order(git_pobject **wo, unsigned int *endp,
git_pobject *po)
{
git_pobject *root;
for (root = po; root->delta; root = root->delta)
; /* nothing */
add_descendants_to_write_order(wo, endp, root);
}
static int cb_tag_foreach(const char *name, git_oid *oid, void *data)
{
git_packbuilder *pb = data;
git_pobject *po;
khiter_t pos;
GIT_UNUSED(name);
pos = kh_get(oid, pb->object_ix, oid);
if (pos == kh_end(pb->object_ix))
return 0;
po = kh_value(pb->object_ix, pos);
po->tagged = 1;
/* TODO: peel objects */
return 0;
}
static git_pobject **compute_write_order(git_packbuilder *pb)
{
unsigned int i, wo_end, last_untagged;
git_pobject **wo = git__malloc(sizeof(*wo) * pb->nr_objects);
for (i = 0; i < pb->nr_objects; i++) {
git_pobject *po = pb->object_list + i;
po->tagged = 0;
po->filled = 0;
po->delta_child = NULL;
po->delta_sibling = NULL;
}
/*
* Fully connect delta_child/delta_sibling network.
* Make sure delta_sibling is sorted in the original
* recency order.
*/
for (i = pb->nr_objects; i > 0;) {
git_pobject *po = &pb->object_list[--i];
if (!po->delta)
continue;
/* Mark me as the first child */
po->delta_sibling = po->delta->delta_child;
po->delta->delta_child = po;
}
/*
* Mark objects that are at the tip of tags.
*/
if (git_tag_foreach(pb->repo, &cb_tag_foreach, pb) < 0)
return NULL;
/*
* Give the objects in the original recency order until
* we see a tagged tip.
*/
for (i = wo_end = 0; i < pb->nr_objects; i++) {
git_pobject *po = pb->object_list + i;
if (po->tagged)
break;
add_to_write_order(wo, &wo_end, po);
}
last_untagged = i;
/*
* Then fill all the tagged tips.
*/
for (; i < pb->nr_objects; i++) {
git_pobject *po = pb->object_list + i;
if (po->tagged)
add_to_write_order(wo, &wo_end, po);
}
/*
* And then all remaining commits and tags.
*/
for (i = last_untagged; i < pb->nr_objects; i++) {
git_pobject *po = pb->object_list + i;
if (po->type != GIT_OBJ_COMMIT &&
po->type != GIT_OBJ_TAG)
continue;
add_to_write_order(wo, &wo_end, po);
}
/*
* And then all the trees.
*/
for (i = last_untagged; i < pb->nr_objects; i++) {
git_pobject *po = pb->object_list + i;
if (po->type != GIT_OBJ_TREE)
continue;
add_to_write_order(wo, &wo_end, po);
}
/*
* Finally all the rest in really tight order
*/
for (i = last_untagged; i < pb->nr_objects; i++) {
git_pobject *po = pb->object_list + i;
if (!po->filled)
add_family_to_write_order(wo, &wo_end, po);
}
if (wo_end != pb->nr_objects) {
giterr_set(GITERR_INVALID, "invalid write order");
return NULL;
}
return wo;
}
static int write_pack(git_packbuilder *pb,
int (*cb)(void *buf, size_t size, void *data),
void *data)
{
git_pobject **write_order;
git_pobject *po;
git_buf buf = GIT_BUF_INIT;
enum write_one_status status;
struct git_pack_header ph;
unsigned int i = 0;
write_order = compute_write_order(pb);
if (write_order == NULL)
goto on_error;
/* Write pack header */
ph.hdr_signature = htonl(PACK_SIGNATURE);
ph.hdr_version = htonl(PACK_VERSION);
ph.hdr_entries = htonl(pb->nr_objects);
if (cb(&ph, sizeof(ph), data) < 0)
goto on_error;
if (git_hash_update(&pb->ctx, &ph, sizeof(ph)) < 0)
goto on_error;
pb->nr_remaining = pb->nr_objects;
do {
pb->nr_written = 0;
for ( ; i < pb->nr_objects; ++i) {
po = write_order[i];
if (write_one(&buf, pb, po, &status) < 0)
goto on_error;
if (cb(buf.ptr, buf.size, data) < 0)
goto on_error;
git_buf_clear(&buf);
}
pb->nr_remaining -= pb->nr_written;
} while (pb->nr_remaining && i < pb->nr_objects);
git__free(write_order);
git_buf_free(&buf);
if (git_hash_final(&pb->pack_oid, &pb->ctx) < 0)
goto on_error;
return cb(pb->pack_oid.id, GIT_OID_RAWSZ, data);
on_error:
git__free(write_order);
git_buf_free(&buf);
return -1;
}
static int write_pack_buf(void *buf, size_t size, void *data)
{
git_buf *b = (git_buf *)data;
return git_buf_put(b, buf, size);
}
static int write_pack_to_file(void *buf, size_t size, void *data)
{
git_filebuf *file = (git_filebuf *)data;
return git_filebuf_write(file, buf, size);
}
static int write_pack_file(git_packbuilder *pb, const char *path)
{
git_filebuf file = GIT_FILEBUF_INIT;
if (git_filebuf_open(&file, path, 0) < 0 ||
write_pack(pb, &write_pack_to_file, &file) < 0 ||
git_filebuf_commit(&file, GIT_PACK_FILE_MODE) < 0) {
git_filebuf_cleanup(&file);
return -1;
}
return 0;
}
static int type_size_sort(const void *_a, const void *_b)
{
const git_pobject *a = (git_pobject *)_a;
const git_pobject *b = (git_pobject *)_b;
if (a->type > b->type)
return -1;
if (a->type < b->type)
return 1;
if (a->hash > b->hash)
return -1;
if (a->hash < b->hash)
return 1;
/*
* TODO
*
if (a->preferred_base > b->preferred_base)
return -1;
if (a->preferred_base < b->preferred_base)
return 1;
*/
if (a->size > b->size)
return -1;
if (a->size < b->size)
return 1;
return a < b ? -1 : (a > b); /* newest first */
}
static int delta_cacheable(git_packbuilder *pb, unsigned long src_size,
unsigned long trg_size, unsigned long delta_size)
{
if (pb->max_delta_cache_size &&
pb->delta_cache_size + delta_size > pb->max_delta_cache_size)
return 0;
if (delta_size < pb->cache_max_small_delta_size)
return 1;
/* cache delta, if objects are large enough compared to delta size */
if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
return 1;
return 0;
}
static int try_delta(git_packbuilder *pb, struct unpacked *trg,
struct unpacked *src, unsigned int max_depth,
unsigned long *mem_usage, int *ret)
{
git_pobject *trg_object = trg->object;
git_pobject *src_object = src->object;
git_odb_object *obj;
unsigned long trg_size, src_size, delta_size,
sizediff, max_size, sz;
unsigned int ref_depth;
void *delta_buf;
/* Don't bother doing diffs between different types */
if (trg_object->type != src_object->type) {
*ret = -1;
return 0;
}
*ret = 0;
/* TODO: support reuse-delta */
/* Let's not bust the allowed depth. */
if (src->depth >= max_depth)
return 0;
/* Now some size filtering heuristics. */
trg_size = (unsigned long)trg_object->size;
if (!trg_object->delta) {
max_size = trg_size/2 - 20;
ref_depth = 1;
} else {
max_size = trg_object->delta_size;
ref_depth = trg->depth;
}
max_size = (uint64_t)max_size * (max_depth - src->depth) /
(max_depth - ref_depth + 1);
if (max_size == 0)
return 0;
src_size = (unsigned long)src_object->size;
sizediff = src_size < trg_size ? trg_size - src_size : 0;
if (sizediff >= max_size)
return 0;
if (trg_size < src_size / 32)
return 0;
/* Load data if not already done */
if (!trg->data) {
if (git_odb_read(&obj, pb->odb, &trg_object->id) < 0)
return -1;
sz = (unsigned long)git_odb_object_size(obj);
trg->data = git__malloc(sz);
GITERR_CHECK_ALLOC(trg->data);
memcpy(trg->data, git_odb_object_data(obj), sz);
git_odb_object_free(obj);
if (sz != trg_size) {
giterr_set(GITERR_INVALID,
"Inconsistent target object length");
return -1;
}
*mem_usage += sz;
}
if (!src->data) {
if (git_odb_read(&obj, pb->odb, &src_object->id) < 0)
return -1;
sz = (unsigned long)git_odb_object_size(obj);
src->data = git__malloc(sz);
GITERR_CHECK_ALLOC(src->data);
memcpy(src->data, git_odb_object_data(obj), sz);
git_odb_object_free(obj);
if (sz != src_size) {
giterr_set(GITERR_INVALID,
"Inconsistent source object length");
return -1;
}
*mem_usage += sz;
}
if (!src->index) {
src->index = git_delta_create_index(src->data, src_size);
if (!src->index)
return 0; /* suboptimal pack - out of memory */
*mem_usage += git_delta_sizeof_index(src->index);
}
delta_buf = git_delta_create(src->index, trg->data, trg_size,
&delta_size, max_size);
if (!delta_buf)
return 0;
if (trg_object->delta) {
/* Prefer only shallower same-sized deltas. */
if (delta_size == trg_object->delta_size &&
src->depth + 1 >= trg->depth) {
git__free(delta_buf);
return 0;
}
}
git_packbuilder__cache_lock(pb);
if (trg_object->delta_data) {
git__free(trg_object->delta_data);
pb->delta_cache_size -= trg_object->delta_size;
trg_object->delta_data = NULL;
}
if (delta_cacheable(pb, src_size, trg_size, delta_size)) {
pb->delta_cache_size += delta_size;
git_packbuilder__cache_unlock(pb);
trg_object->delta_data = git__realloc(delta_buf, delta_size);
GITERR_CHECK_ALLOC(trg_object->delta_data);
} else {
/* create delta when writing the pack */
git_packbuilder__cache_unlock(pb);
git__free(delta_buf);
}
trg_object->delta = src_object;
trg_object->delta_size = delta_size;
trg->depth = src->depth + 1;
*ret = 1;
return 0;
}
static unsigned int check_delta_limit(git_pobject *me, unsigned int n)
{
git_pobject *child = me->delta_child;
unsigned int m = n;
while (child) {
unsigned int c = check_delta_limit(child, n + 1);
if (m < c)
m = c;
child = child->delta_sibling;
}
return m;
}
static unsigned long free_unpacked(struct unpacked *n)
{
unsigned long freed_mem = git_delta_sizeof_index(n->index);
git_delta_free_index(n->index);
n->index = NULL;
if (n->data) {
freed_mem += (unsigned long)n->object->size;
git__free(n->data);
n->data = NULL;
}
n->object = NULL;
n->depth = 0;
return freed_mem;
}
static int find_deltas(git_packbuilder *pb, git_pobject **list,
unsigned int *list_size, unsigned int window,
unsigned int depth)
{
git_pobject *po;
git_buf zbuf = GIT_BUF_INIT;
struct unpacked *array;
uint32_t idx = 0, count = 0;
unsigned long mem_usage = 0;
unsigned int i;
int error = -1;
array = git__calloc(window, sizeof(struct unpacked));
GITERR_CHECK_ALLOC(array);
for (;;) {
struct unpacked *n = array + idx;
unsigned int max_depth;
int j, best_base = -1;
git_packbuilder__progress_lock(pb);
if (!*list_size) {
git_packbuilder__progress_unlock(pb);
break;
}
po = *list++;
(*list_size)--;
git_packbuilder__progress_unlock(pb);
mem_usage -= free_unpacked(n);
n->object = po;
while (pb->window_memory_limit &&
mem_usage > pb->window_memory_limit &&
count > 1) {
uint32_t tail = (idx + window - count) % window;
mem_usage -= free_unpacked(array + tail);
count--;
}
/*
* If the current object is at pack edge, take the depth the
* objects that depend on the current object into account
* otherwise they would become too deep.
*/
max_depth = depth;
if (po->delta_child) {
max_depth -= check_delta_limit(po, 0);
if (max_depth <= 0)
goto next;
}
j = window;
while (--j > 0) {
int ret;
uint32_t other_idx = idx + j;
struct unpacked *m;
if (other_idx >= window)
other_idx -= window;
m = array + other_idx;
if (!m->object)
break;
if (try_delta(pb, n, m, max_depth, &mem_usage, &ret) < 0)
goto on_error;
if (ret < 0)
break;
else if (ret > 0)
best_base = other_idx;
}
/*
* If we decided to cache the delta data, then it is best
* to compress it right away. First because we have to do
* it anyway, and doing it here while we're threaded will
* save a lot of time in the non threaded write phase,
* as well as allow for caching more deltas within
* the same cache size limit.
* ...
* But only if not writing to stdout, since in that case
* the network is most likely throttling writes anyway,
* and therefore it is best to go to the write phase ASAP
* instead, as we can afford spending more time compressing
* between writes at that moment.
*/
if (po->delta_data) {
if (git__compress(&zbuf, po->delta_data, po->delta_size) < 0)
goto on_error;
git__free(po->delta_data);
po->delta_data = git__malloc(zbuf.size);
GITERR_CHECK_ALLOC(po->delta_data);
memcpy(po->delta_data, zbuf.ptr, zbuf.size);
po->z_delta_size = (unsigned long)zbuf.size;
git_buf_clear(&zbuf);
git_packbuilder__cache_lock(pb);
pb->delta_cache_size -= po->delta_size;
pb->delta_cache_size += po->z_delta_size;
git_packbuilder__cache_unlock(pb);
}
/*
* If we made n a delta, and if n is already at max
* depth, leaving it in the window is pointless. we
* should evict it first.
*/
if (po->delta && max_depth <= n->depth)
continue;
/*
* Move the best delta base up in the window, after the
* currently deltified object, to keep it longer. It will
* be the first base object to be attempted next.
*/
if (po->delta) {
struct unpacked swap = array[best_base];
int dist = (window + idx - best_base) % window;
int dst = best_base;
while (dist--) {
int src = (dst + 1) % window;
array[dst] = array[src];
dst = src;
}
array[dst] = swap;
}
next:
idx++;
if (count + 1 < window)
count++;
if (idx >= window)
idx = 0;
}
error = 0;
on_error:
for (i = 0; i < window; ++i) {
git__free(array[i].index);
git__free(array[i].data);
}
git__free(array);
git_buf_free(&zbuf);
return error;
}
#ifdef GIT_THREADS
struct thread_params {
git_thread thread;
git_packbuilder *pb;
git_pobject **list;
git_cond cond;
git_mutex mutex;
unsigned int list_size;
unsigned int remaining;
int window;
int depth;
int working;
int data_ready;
};
static void *threaded_find_deltas(void *arg)
{
struct thread_params *me = arg;
while (me->remaining) {
if (find_deltas(me->pb, me->list, &me->remaining,
me->window, me->depth) < 0) {
; /* TODO */
}
git_packbuilder__progress_lock(me->pb);
me->working = 0;
git_cond_signal(&me->pb->progress_cond);
git_packbuilder__progress_unlock(me->pb);
if (git_mutex_lock(&me->mutex)) {
giterr_set(GITERR_THREAD, "unable to lock packfile condition mutex");
return NULL;
}
while (!me->data_ready)
git_cond_wait(&me->cond, &me->mutex);
/*
* We must not set ->data_ready before we wait on the
* condition because the main thread may have set it to 1
* before we get here. In order to be sure that new
* work is available if we see 1 in ->data_ready, it
* was initialized to 0 before this thread was spawned
* and we reset it to 0 right away.
*/
me->data_ready = 0;
git_mutex_unlock(&me->mutex);
}
/* leave ->working 1 so that this doesn't get more work assigned */
return NULL;
}
static int ll_find_deltas(git_packbuilder *pb, git_pobject **list,
unsigned int list_size, unsigned int window,
unsigned int depth)
{
struct thread_params *p;
int i, ret, active_threads = 0;
if (!pb->nr_threads)
pb->nr_threads = git_online_cpus();
if (pb->nr_threads <= 1) {
find_deltas(pb, list, &list_size, window, depth);
return 0;
}
p = git__malloc(pb->nr_threads * sizeof(*p));
GITERR_CHECK_ALLOC(p);
/* Partition the work among the threads */
for (i = 0; i < pb->nr_threads; ++i) {
unsigned sub_size = list_size / (pb->nr_threads - i);
/* don't use too small segments or no deltas will be found */
if (sub_size < 2*window && i+1 < pb->nr_threads)
sub_size = 0;
p[i].pb = pb;
p[i].window = window;
p[i].depth = depth;
p[i].working = 1;
p[i].data_ready = 0;
/* try to split chunks on "path" boundaries */
while (sub_size && sub_size < list_size &&
list[sub_size]->hash &&
list[sub_size]->hash == list[sub_size-1]->hash)
sub_size++;
p[i].list = list;
p[i].list_size = sub_size;
p[i].remaining = sub_size;
list += sub_size;
list_size -= sub_size;
}
/* Start work threads */
for (i = 0; i < pb->nr_threads; ++i) {
if (!p[i].list_size)
continue;
git_mutex_init(&p[i].mutex);
git_cond_init(&p[i].cond);
ret = git_thread_create(&p[i].thread, NULL,
threaded_find_deltas, &p[i]);
if (ret) {
giterr_set(GITERR_THREAD, "unable to create thread");
return -1;
}
active_threads++;
}
/*
* Now let's wait for work completion. Each time a thread is done
* with its work, we steal half of the remaining work from the
* thread with the largest number of unprocessed objects and give
* it to that newly idle thread. This ensure good load balancing
* until the remaining object list segments are simply too short
* to be worth splitting anymore.
*/
while (active_threads) {
struct thread_params *target = NULL;
struct thread_params *victim = NULL;
unsigned sub_size = 0;
/* Start by locating a thread that has transitioned its
* 'working' flag from 1 -> 0. This indicates that it is
* ready to receive more work using our work-stealing
* algorithm. */
git_packbuilder__progress_lock(pb);
for (;;) {
for (i = 0; !target && i < pb->nr_threads; i++)
if (!p[i].working)
target = &p[i];
if (target)
break;
git_cond_wait(&pb->progress_cond, &pb->progress_mutex);
}
/* At this point we hold the progress lock and have located
* a thread to receive more work. We still need to locate a
* thread from which to steal work (the victim). */
for (i = 0; i < pb->nr_threads; i++)
if (p[i].remaining > 2*window &&
(!victim || victim->remaining < p[i].remaining))
victim = &p[i];
if (victim) {
sub_size = victim->remaining / 2;
list = victim->list + victim->list_size - sub_size;
while (sub_size && list[0]->hash &&
list[0]->hash == list[-1]->hash) {
list++;
sub_size--;
}
if (!sub_size) {
/*
* It is possible for some "paths" to have
* so many objects that no hash boundary
* might be found. Let's just steal the
* exact half in that case.
*/
sub_size = victim->remaining / 2;
list -= sub_size;
}
target->list = list;
victim->list_size -= sub_size;
victim->remaining -= sub_size;
}
target->list_size = sub_size;
target->remaining = sub_size;
target->working = 1;
git_packbuilder__progress_unlock(pb);
if (git_mutex_lock(&target->mutex)) {
giterr_set(GITERR_THREAD, "unable to lock packfile condition mutex");
git__free(p);
return -1;
}
target->data_ready = 1;
git_cond_signal(&target->cond);
git_mutex_unlock(&target->mutex);
if (!sub_size) {
git_thread_join(target->thread, NULL);
git_cond_free(&target->cond);
git_mutex_free(&target->mutex);
active_threads--;
}
}
git__free(p);
return 0;
}
#else
#define ll_find_deltas(pb, l, ls, w, d) find_deltas(pb, l, &ls, w, d)
#endif
static int prepare_pack(git_packbuilder *pb)
{
git_pobject **delta_list;
unsigned int i, n = 0;
if (pb->nr_objects == 0 || pb->done)
return 0; /* nothing to do */
delta_list = git__malloc(pb->nr_objects * sizeof(*delta_list));
GITERR_CHECK_ALLOC(delta_list);
for (i = 0; i < pb->nr_objects; ++i) {
git_pobject *po = pb->object_list + i;
/* Make sure the item is within our size limits */
if (po->size < 50 || po->size > pb->big_file_threshold)
continue;
delta_list[n++] = po;
}
if (n > 1) {
git__tsort((void **)delta_list, n, type_size_sort);
if (ll_find_deltas(pb, delta_list, n,
GIT_PACK_WINDOW + 1,
GIT_PACK_DEPTH) < 0) {
git__free(delta_list);
return -1;
}
}
pb->done = true;
git__free(delta_list);
return 0;
}
#define PREPARE_PACK if (prepare_pack(pb) < 0) { return -1; }
int git_packbuilder_foreach(git_packbuilder *pb, int (*cb)(void *buf, size_t size, void *payload), void *payload)
{
PREPARE_PACK;
return write_pack(pb, cb, payload);
}
int git_packbuilder_write_buf(git_buf *buf, git_packbuilder *pb)
{
PREPARE_PACK;
return write_pack(pb, &write_pack_buf, buf);
}
int git_packbuilder_write(git_packbuilder *pb, const char *path)
{
PREPARE_PACK;
return write_pack_file(pb, path);
}
#undef PREPARE_PACK
static int cb_tree_walk(const char *root, const git_tree_entry *entry, void *payload)
{
struct tree_walk_context *ctx = payload;
/* A commit inside a tree represents a submodule commit and should be skipped. */
if (git_tree_entry_type(entry) == GIT_OBJ_COMMIT)
return 0;
if (git_buf_sets(&ctx->buf, root) < 0 ||
git_buf_puts(&ctx->buf, git_tree_entry_name(entry)) < 0)
return -1;
return git_packbuilder_insert(ctx->pb,
git_tree_entry_id(entry),
git_buf_cstr(&ctx->buf));
}
int git_packbuilder_insert_commit(git_packbuilder *pb, const git_oid *oid)
{
git_commit *commit;
if (git_commit_lookup(&commit, pb->repo, oid) < 0 ||
git_packbuilder_insert(pb, oid, NULL) < 0)
return -1;
if (git_packbuilder_insert_tree(pb, git_commit_tree_id(commit)) < 0)
return -1;
git_commit_free(commit);
return 0;
}
int git_packbuilder_insert_tree(git_packbuilder *pb, const git_oid *oid)
{
git_tree *tree;
struct tree_walk_context context = { pb, GIT_BUF_INIT };
if (git_tree_lookup(&tree, pb->repo, oid) < 0 ||
git_packbuilder_insert(pb, oid, NULL) < 0)
return -1;
if (git_tree_walk(tree, GIT_TREEWALK_PRE, cb_tree_walk, &context) < 0) {
git_tree_free(tree);
git_buf_free(&context.buf);
return -1;
}
git_tree_free(tree);
git_buf_free(&context.buf);
return 0;
}
uint32_t git_packbuilder_object_count(git_packbuilder *pb)
{
return pb->nr_objects;
}
uint32_t git_packbuilder_written(git_packbuilder *pb)
{
return pb->nr_written;
}
void git_packbuilder_free(git_packbuilder *pb)
{
if (pb == NULL)
return;
#ifdef GIT_THREADS
git_mutex_free(&pb->cache_mutex);
git_mutex_free(&pb->progress_mutex);
git_cond_free(&pb->progress_cond);
#endif
if (pb->odb)
git_odb_free(pb->odb);
if (pb->object_ix)
git_oidmap_free(pb->object_ix);
if (pb->object_list)
git__free(pb->object_list);
git_hash_ctx_cleanup(&pb->ctx);
git__free(pb);
}
