From: Junio C Hamano <junkio@cox.net>
Date: Sun, 13 Aug 2006 02:33:16 +0000 (-0700)
Subject: Merge branch 'jc/pack-objects'
X-Git-Tag: v1.4.3-rc1~270
X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=647377c4c91064fc5001acddd5357467c0da6ef9;p=git.git

Merge branch 'jc/pack-objects'
---

647377c4c91064fc5001acddd5357467c0da6ef9
diff --cc builtin-pack-objects.c
index 2301cd5c0,000000000..2f9921224
mode 100644,000000..100644
--- a/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@@ -1,1376 -1,0 +1,1392 @@@
 +#include "builtin.h"
 +#include "cache.h"
 +#include "object.h"
 +#include "blob.h"
 +#include "commit.h"
 +#include "tag.h"
 +#include "tree.h"
 +#include "delta.h"
 +#include "pack.h"
 +#include "csum-file.h"
 +#include "tree-walk.h"
 +#include <sys/time.h>
 +#include <signal.h>
 +
 +static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
 +
 +struct object_entry {
 +	unsigned char sha1[20];
 +	unsigned long size;	/* uncompressed size */
 +	unsigned long offset;	/* offset into the final pack file;
 +				 * nonzero if already written.
 +				 */
 +	unsigned int depth;	/* delta depth */
 +	unsigned int delta_limit;	/* base adjustment for in-pack delta */
 +	unsigned int hash;	/* name hint hash */
 +	enum object_type type;
 +	enum object_type in_pack_type;	/* could be delta */
 +	unsigned long delta_size;	/* delta data size (uncompressed) */
 +	struct object_entry *delta;	/* delta base object */
 +	struct packed_git *in_pack; 	/* already in pack */
 +	unsigned int in_pack_offset;
 +	struct object_entry *delta_child; /* deltified objects who bases me */
 +	struct object_entry *delta_sibling; /* other deltified objects who
 +					     * uses the same base as me
 +					     */
 +	int preferred_base;	/* we do not pack this, but is encouraged to
 +				 * be used as the base objectto delta huge
 +				 * objects against.
 +				 */
 +};
 +
 +/*
 + * Objects we are going to pack are collected in objects array (dynamically
 + * expanded).  nr_objects & nr_alloc controls this array.  They are stored
 + * in the order we see -- typically rev-list --objects order that gives us
 + * nice "minimum seek" order.
 + *
 + * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
 + * elements in the objects array.  The former is used to build the pack
 + * index (lists object names in the ascending order to help offset lookup),
 + * and the latter is used to group similar things together by try_delta()
 + * heuristics.
 + */
 +
 +static unsigned char object_list_sha1[20];
 +static int non_empty = 0;
 +static int no_reuse_delta = 0;
 +static int local = 0;
 +static int incremental = 0;
 +static struct object_entry **sorted_by_sha, **sorted_by_type;
 +static struct object_entry *objects = NULL;
 +static int nr_objects = 0, nr_alloc = 0, nr_result = 0;
 +static const char *base_name;
 +static unsigned char pack_file_sha1[20];
 +static int progress = 1;
 +static volatile sig_atomic_t progress_update = 0;
 +static int window = 10;
 +
 +/*
 + * The object names in objects array are hashed with this hashtable,
 + * to help looking up the entry by object name.  Binary search from
 + * sorted_by_sha is also possible but this was easier to code and faster.
 + * This hashtable is built after all the objects are seen.
 + */
 +static int *object_ix = NULL;
 +static int object_ix_hashsz = 0;
 +
 +/*
 + * Pack index for existing packs give us easy access to the offsets into
 + * corresponding pack file where each object's data starts, but the entries
 + * do not store the size of the compressed representation (uncompressed
 + * size is easily available by examining the pack entry header).  We build
 + * a hashtable of existing packs (pack_revindex), and keep reverse index
 + * here -- pack index file is sorted by object name mapping to offset; this
 + * pack_revindex[].revindex array is an ordered list of offsets, so if you
 + * know the offset of an object, next offset is where its packed
 + * representation ends.
 + */
 +struct pack_revindex {
 +	struct packed_git *p;
 +	unsigned long *revindex;
 +} *pack_revindex = NULL;
 +static int pack_revindex_hashsz = 0;
 +
 +/*
 + * stats
 + */
 +static int written = 0;
 +static int written_delta = 0;
 +static int reused = 0;
 +static int reused_delta = 0;
 +
 +static int pack_revindex_ix(struct packed_git *p)
 +{
 +	unsigned long ui = (unsigned long)p;
 +	int i;
 +
 +	ui = ui ^ (ui >> 16); /* defeat structure alignment */
 +	i = (int)(ui % pack_revindex_hashsz);
 +	while (pack_revindex[i].p) {
 +		if (pack_revindex[i].p == p)
 +			return i;
 +		if (++i == pack_revindex_hashsz)
 +			i = 0;
 +	}
 +	return -1 - i;
 +}
 +
 +static void prepare_pack_ix(void)
 +{
 +	int num;
 +	struct packed_git *p;
 +	for (num = 0, p = packed_git; p; p = p->next)
 +		num++;
 +	if (!num)
 +		return;
 +	pack_revindex_hashsz = num * 11;
 +	pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
 +	for (p = packed_git; p; p = p->next) {
 +		num = pack_revindex_ix(p);
 +		num = - 1 - num;
 +		pack_revindex[num].p = p;
 +	}
 +	/* revindex elements are lazily initialized */
 +}
 +
 +static int cmp_offset(const void *a_, const void *b_)
 +{
 +	unsigned long a = *(unsigned long *) a_;
 +	unsigned long b = *(unsigned long *) b_;
 +	if (a < b)
 +		return -1;
 +	else if (a == b)
 +		return 0;
 +	else
 +		return 1;
 +}
 +
 +/*
 + * Ordered list of offsets of objects in the pack.
 + */
 +static void prepare_pack_revindex(struct pack_revindex *rix)
 +{
 +	struct packed_git *p = rix->p;
 +	int num_ent = num_packed_objects(p);
 +	int i;
 +	void *index = p->index_base + 256;
 +
 +	rix->revindex = xmalloc(sizeof(unsigned long) * (num_ent + 1));
 +	for (i = 0; i < num_ent; i++) {
 +		unsigned int hl = *((unsigned int *)((char *) index + 24*i));
 +		rix->revindex[i] = ntohl(hl);
 +	}
 +	/* This knows the pack format -- the 20-byte trailer
 +	 * follows immediately after the last object data.
 +	 */
 +	rix->revindex[num_ent] = p->pack_size - 20;
 +	qsort(rix->revindex, num_ent, sizeof(unsigned long), cmp_offset);
 +}
 +
 +static unsigned long find_packed_object_size(struct packed_git *p,
 +					     unsigned long ofs)
 +{
 +	int num;
 +	int lo, hi;
 +	struct pack_revindex *rix;
 +	unsigned long *revindex;
 +	num = pack_revindex_ix(p);
 +	if (num < 0)
 +		die("internal error: pack revindex uninitialized");
 +	rix = &pack_revindex[num];
 +	if (!rix->revindex)
 +		prepare_pack_revindex(rix);
 +	revindex = rix->revindex;
 +	lo = 0;
 +	hi = num_packed_objects(p) + 1;
 +	do {
 +		int mi = (lo + hi) / 2;
 +		if (revindex[mi] == ofs) {
 +			return revindex[mi+1] - ofs;
 +		}
 +		else if (ofs < revindex[mi])
 +			hi = mi;
 +		else
 +			lo = mi + 1;
 +	} while (lo < hi);
 +	die("internal error: pack revindex corrupt");
 +}
 +
 +static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 +{
 +	unsigned long othersize, delta_size;
 +	char type[10];
 +	void *otherbuf = read_sha1_file(entry->delta->sha1, type, &othersize);
 +	void *delta_buf;
 +
 +	if (!otherbuf)
 +		die("unable to read %s", sha1_to_hex(entry->delta->sha1));
 +        delta_buf = diff_delta(otherbuf, othersize,
 +			       buf, size, &delta_size, 0);
 +        if (!delta_buf || delta_size != entry->delta_size)
 +        	die("delta size changed");
 +        free(buf);
 +        free(otherbuf);
 +	return delta_buf;
 +}
 +
 +/*
 + * The per-object header is a pretty dense thing, which is
 + *  - first byte: low four bits are "size", then three bits of "type",
 + *    and the high bit is "size continues".
 + *  - each byte afterwards: low seven bits are size continuation,
 + *    with the high bit being "size continues"
 + */
 +static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 +{
 +	int n = 1;
 +	unsigned char c;
 +
 +	if (type < OBJ_COMMIT || type > OBJ_DELTA)
 +		die("bad type %d", type);
 +
 +	c = (type << 4) | (size & 15);
 +	size >>= 4;
 +	while (size) {
 +		*hdr++ = c | 0x80;
 +		c = size & 0x7f;
 +		size >>= 7;
 +		n++;
 +	}
 +	*hdr = c;
 +	return n;
 +}
 +
 +static unsigned long write_object(struct sha1file *f,
 +				  struct object_entry *entry)
 +{
 +	unsigned long size;
 +	char type[10];
 +	void *buf;
 +	unsigned char header[10];
 +	unsigned hdrlen, datalen;
 +	enum object_type obj_type;
 +	int to_reuse = 0;
 +
 +	if (entry->preferred_base)
 +		return 0;
 +
 +	obj_type = entry->type;
 +	if (! entry->in_pack)
 +		to_reuse = 0;	/* can't reuse what we don't have */
 +	else if (obj_type == OBJ_DELTA)
 +		to_reuse = 1;	/* check_object() decided it for us */
 +	else if (obj_type != entry->in_pack_type)
 +		to_reuse = 0;	/* pack has delta which is unusable */
 +	else if (entry->delta)
 +		to_reuse = 0;	/* we want to pack afresh */
 +	else
 +		to_reuse = 1;	/* we have it in-pack undeltified,
 +				 * and we do not need to deltify it.
 +				 */
 +
++	if (!entry->in_pack && !entry->delta) {
++		unsigned char *map;
++		unsigned long mapsize;
++		map = map_sha1_file(entry->sha1, &mapsize);
++		if (map && !legacy_loose_object(map)) {
++			/* We can copy straight into the pack file */
++			sha1write(f, map, mapsize);
++			munmap(map, mapsize);
++			written++;
++			reused++;
++			return mapsize;
++		}
++		if (map)
++			munmap(map, mapsize);
++	}
++
 +	if (! to_reuse) {
 +		buf = read_sha1_file(entry->sha1, type, &size);
 +		if (!buf)
 +			die("unable to read %s", sha1_to_hex(entry->sha1));
 +		if (size != entry->size)
 +			die("object %s size inconsistency (%lu vs %lu)",
 +			    sha1_to_hex(entry->sha1), size, entry->size);
 +		if (entry->delta) {
 +			buf = delta_against(buf, size, entry);
 +			size = entry->delta_size;
 +			obj_type = OBJ_DELTA;
 +		}
 +		/*
 +		 * The object header is a byte of 'type' followed by zero or
 +		 * more bytes of length.  For deltas, the 20 bytes of delta
 +		 * sha1 follows that.
 +		 */
 +		hdrlen = encode_header(obj_type, size, header);
 +		sha1write(f, header, hdrlen);
 +
 +		if (entry->delta) {
 +			sha1write(f, entry->delta, 20);
 +			hdrlen += 20;
 +		}
 +		datalen = sha1write_compressed(f, buf, size);
 +		free(buf);
 +	}
 +	else {
 +		struct packed_git *p = entry->in_pack;
 +		use_packed_git(p);
 +
 +		datalen = find_packed_object_size(p, entry->in_pack_offset);
 +		buf = (char *) p->pack_base + entry->in_pack_offset;
 +		sha1write(f, buf, datalen);
 +		unuse_packed_git(p);
 +		hdrlen = 0; /* not really */
 +		if (obj_type == OBJ_DELTA)
 +			reused_delta++;
 +		reused++;
 +	}
 +	if (obj_type == OBJ_DELTA)
 +		written_delta++;
 +	written++;
 +	return hdrlen + datalen;
 +}
 +
 +static unsigned long write_one(struct sha1file *f,
 +			       struct object_entry *e,
 +			       unsigned long offset)
 +{
 +	if (e->offset)
 +		/* offset starts from header size and cannot be zero
 +		 * if it is written already.
 +		 */
 +		return offset;
 +	e->offset = offset;
 +	offset += write_object(f, e);
 +	/* if we are deltified, write out its base object. */
 +	if (e->delta)
 +		offset = write_one(f, e->delta, offset);
 +	return offset;
 +}
 +
 +static void write_pack_file(void)
 +{
 +	int i;
 +	struct sha1file *f;
 +	unsigned long offset;
 +	struct pack_header hdr;
 +	unsigned last_percent = 999;
 +	int do_progress = 0;
 +
 +	if (!base_name)
 +		f = sha1fd(1, "<stdout>");
 +	else {
 +		f = sha1create("%s-%s.%s", base_name,
 +			       sha1_to_hex(object_list_sha1), "pack");
 +		do_progress = progress;
 +	}
 +	if (do_progress)
 +		fprintf(stderr, "Writing %d objects.\n", nr_result);
 +
 +	hdr.hdr_signature = htonl(PACK_SIGNATURE);
 +	hdr.hdr_version = htonl(PACK_VERSION);
 +	hdr.hdr_entries = htonl(nr_result);
 +	sha1write(f, &hdr, sizeof(hdr));
 +	offset = sizeof(hdr);
 +	if (!nr_result)
 +		goto done;
 +	for (i = 0; i < nr_objects; i++) {
 +		offset = write_one(f, objects + i, offset);
 +		if (do_progress) {
 +			unsigned percent = written * 100 / nr_result;
 +			if (progress_update || percent != last_percent) {
 +				fprintf(stderr, "%4u%% (%u/%u) done\r",
 +					percent, written, nr_result);
 +				progress_update = 0;
 +				last_percent = percent;
 +			}
 +		}
 +	}
 +	if (do_progress)
 +		fputc('\n', stderr);
 + done:
 +	sha1close(f, pack_file_sha1, 1);
 +}
 +
 +static void write_index_file(void)
 +{
 +	int i;
 +	struct sha1file *f = sha1create("%s-%s.%s", base_name,
 +					sha1_to_hex(object_list_sha1), "idx");
 +	struct object_entry **list = sorted_by_sha;
 +	struct object_entry **last = list + nr_result;
 +	unsigned int array[256];
 +
 +	/*
 +	 * Write the first-level table (the list is sorted,
 +	 * but we use a 256-entry lookup to be able to avoid
 +	 * having to do eight extra binary search iterations).
 +	 */
 +	for (i = 0; i < 256; i++) {
 +		struct object_entry **next = list;
 +		while (next < last) {
 +			struct object_entry *entry = *next;
 +			if (entry->sha1[0] != i)
 +				break;
 +			next++;
 +		}
 +		array[i] = htonl(next - sorted_by_sha);
 +		list = next;
 +	}
 +	sha1write(f, array, 256 * sizeof(int));
 +
 +	/*
 +	 * Write the actual SHA1 entries..
 +	 */
 +	list = sorted_by_sha;
 +	for (i = 0; i < nr_result; i++) {
 +		struct object_entry *entry = *list++;
 +		unsigned int offset = htonl(entry->offset);
 +		sha1write(f, &offset, 4);
 +		sha1write(f, entry->sha1, 20);
 +	}
 +	sha1write(f, pack_file_sha1, 20);
 +	sha1close(f, NULL, 1);
 +}
 +
 +static int locate_object_entry_hash(const unsigned char *sha1)
 +{
 +	int i;
 +	unsigned int ui;
 +	memcpy(&ui, sha1, sizeof(unsigned int));
 +	i = ui % object_ix_hashsz;
 +	while (0 < object_ix[i]) {
 +		if (!memcmp(sha1, objects[object_ix[i]-1].sha1, 20))
 +			return i;
 +		if (++i == object_ix_hashsz)
 +			i = 0;
 +	}
 +	return -1 - i;
 +}
 +
 +static struct object_entry *locate_object_entry(const unsigned char *sha1)
 +{
 +	int i;
 +
 +	if (!object_ix_hashsz)
 +		return NULL;
 +
 +	i = locate_object_entry_hash(sha1);
 +	if (0 <= i)
 +		return &objects[object_ix[i]-1];
 +	return NULL;
 +}
 +
 +static void rehash_objects(void)
 +{
 +	int i;
 +	struct object_entry *oe;
 +
 +	object_ix_hashsz = nr_objects * 3;
 +	if (object_ix_hashsz < 1024)
 +		object_ix_hashsz = 1024;
 +	object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 +	memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 +	for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 +		int ix = locate_object_entry_hash(oe->sha1);
 +		if (0 <= ix)
 +			continue;
 +		ix = -1 - ix;
 +		object_ix[ix] = i + 1;
 +	}
 +}
 +
 +static unsigned name_hash(const char *name)
 +{
 +	unsigned char c;
 +	unsigned hash = 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 (isspace(c))
 +			continue;
 +		hash = (hash >> 2) + (c << 24);
 +	}
 +	return hash;
 +}
 +
 +static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclude)
 +{
 +	unsigned int idx = nr_objects;
 +	struct object_entry *entry;
 +	struct packed_git *p;
 +	unsigned int found_offset = 0;
 +	struct packed_git *found_pack = NULL;
 +	int ix, status = 0;
 +
 +	if (!exclude) {
 +		for (p = packed_git; p; p = p->next) {
 +			struct pack_entry e;
 +			if (find_pack_entry_one(sha1, &e, p)) {
 +				if (incremental)
 +					return 0;
 +				if (local && !p->pack_local)
 +					return 0;
 +				if (!found_pack) {
 +					found_offset = e.offset;
 +					found_pack = e.p;
 +				}
 +			}
 +		}
 +	}
 +	if ((entry = locate_object_entry(sha1)) != NULL)
 +		goto already_added;
 +
 +	if (idx >= nr_alloc) {
 +		unsigned int needed = (idx + 1024) * 3 / 2;
 +		objects = xrealloc(objects, needed * sizeof(*entry));
 +		nr_alloc = needed;
 +	}
 +	entry = objects + idx;
 +	nr_objects = idx + 1;
 +	memset(entry, 0, sizeof(*entry));
 +	memcpy(entry->sha1, sha1, 20);
 +	entry->hash = hash;
 +
 +	if (object_ix_hashsz * 3 <= nr_objects * 4)
 +		rehash_objects();
 +	else {
 +		ix = locate_object_entry_hash(entry->sha1);
 +		if (0 <= ix)
 +			die("internal error in object hashing.");
 +		object_ix[-1 - ix] = idx + 1;
 +	}
 +	status = 1;
 +
 + already_added:
 +	if (progress_update) {
 +		fprintf(stderr, "Counting objects...%d\r", nr_objects);
 +		progress_update = 0;
 +	}
 +	if (exclude)
 +		entry->preferred_base = 1;
 +	else {
 +		if (found_pack) {
 +			entry->in_pack = found_pack;
 +			entry->in_pack_offset = found_offset;
 +		}
 +	}
 +	return status;
 +}
 +
 +struct pbase_tree_cache {
 +	unsigned char sha1[20];
 +	int ref;
 +	int temporary;
 +	void *tree_data;
 +	unsigned long tree_size;
 +};
 +
 +static struct pbase_tree_cache *(pbase_tree_cache[256]);
 +static int pbase_tree_cache_ix(const unsigned char *sha1)
 +{
 +	return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 +}
 +static int pbase_tree_cache_ix_incr(int ix)
 +{
 +	return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 +}
 +
 +static struct pbase_tree {
 +	struct pbase_tree *next;
 +	/* This is a phony "cache" entry; we are not
 +	 * going to evict it nor find it through _get()
 +	 * mechanism -- this is for the toplevel node that
 +	 * would almost always change with any commit.
 +	 */
 +	struct pbase_tree_cache pcache;
 +} *pbase_tree;
 +
 +static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 +{
 +	struct pbase_tree_cache *ent, *nent;
 +	void *data;
 +	unsigned long size;
 +	char type[20];
 +	int neigh;
 +	int my_ix = pbase_tree_cache_ix(sha1);
 +	int available_ix = -1;
 +
 +	/* pbase-tree-cache acts as a limited hashtable.
 +	 * your object will be found at your index or within a few
 +	 * slots after that slot if it is cached.
 +	 */
 +	for (neigh = 0; neigh < 8; neigh++) {
 +		ent = pbase_tree_cache[my_ix];
 +		if (ent && !memcmp(ent->sha1, sha1, 20)) {
 +			ent->ref++;
 +			return ent;
 +		}
 +		else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 +			 ((0 <= available_ix) &&
 +			  (!ent && pbase_tree_cache[available_ix])))
 +			available_ix = my_ix;
 +		if (!ent)
 +			break;
 +		my_ix = pbase_tree_cache_ix_incr(my_ix);
 +	}
 +
 +	/* Did not find one.  Either we got a bogus request or
 +	 * we need to read and perhaps cache.
 +	 */
 +	data = read_sha1_file(sha1, type, &size);
 +	if (!data)
 +		return NULL;
 +	if (strcmp(type, tree_type)) {
 +		free(data);
 +		return NULL;
 +	}
 +
 +	/* We need to either cache or return a throwaway copy */
 +
 +	if (available_ix < 0)
 +		ent = NULL;
 +	else {
 +		ent = pbase_tree_cache[available_ix];
 +		my_ix = available_ix;
 +	}
 +
 +	if (!ent) {
 +		nent = xmalloc(sizeof(*nent));
 +		nent->temporary = (available_ix < 0);
 +	}
 +	else {
 +		/* evict and reuse */
 +		free(ent->tree_data);
 +		nent = ent;
 +	}
 +	memcpy(nent->sha1, sha1, 20);
 +	nent->tree_data = data;
 +	nent->tree_size = size;
 +	nent->ref = 1;
 +	if (!nent->temporary)
 +		pbase_tree_cache[my_ix] = nent;
 +	return nent;
 +}
 +
 +static void pbase_tree_put(struct pbase_tree_cache *cache)
 +{
 +	if (!cache->temporary) {
 +		cache->ref--;
 +		return;
 +	}
 +	free(cache->tree_data);
 +	free(cache);
 +}
 +
 +static int name_cmp_len(const char *name)
 +{
 +	int i;
 +	for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 +		;
 +	return i;
 +}
 +
 +static void add_pbase_object(struct tree_desc *tree,
 +			     const char *name,
 +			     int cmplen,
 +			     const char *fullname)
 +{
 +	struct name_entry entry;
 +
 +	while (tree_entry(tree,&entry)) {
 +		unsigned long size;
 +		char type[20];
 +
 +		if (entry.pathlen != cmplen ||
 +		    memcmp(entry.path, name, cmplen) ||
 +		    !has_sha1_file(entry.sha1) ||
 +		    sha1_object_info(entry.sha1, type, &size))
 +			continue;
 +		if (name[cmplen] != '/') {
 +			unsigned hash = name_hash(fullname);
 +			add_object_entry(entry.sha1, hash, 1);
 +			return;
 +		}
 +		if (!strcmp(type, tree_type)) {
 +			struct tree_desc sub;
 +			struct pbase_tree_cache *tree;
 +			const char *down = name+cmplen+1;
 +			int downlen = name_cmp_len(down);
 +
 +			tree = pbase_tree_get(entry.sha1);
 +			if (!tree)
 +				return;
 +			sub.buf = tree->tree_data;
 +			sub.size = tree->tree_size;
 +
 +			add_pbase_object(&sub, down, downlen, fullname);
 +			pbase_tree_put(tree);
 +		}
 +	}
 +}
 +
 +static unsigned *done_pbase_paths;
 +static int done_pbase_paths_num;
 +static int done_pbase_paths_alloc;
 +static int done_pbase_path_pos(unsigned hash)
 +{
 +	int lo = 0;
 +	int hi = done_pbase_paths_num;
 +	while (lo < hi) {
 +		int mi = (hi + lo) / 2;
 +		if (done_pbase_paths[mi] == hash)
 +			return mi;
 +		if (done_pbase_paths[mi] < hash)
 +			hi = mi;
 +		else
 +			lo = mi + 1;
 +	}
 +	return -lo-1;
 +}
 +
 +static int check_pbase_path(unsigned hash)
 +{
 +	int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
 +	if (0 <= pos)
 +		return 1;
 +	pos = -pos - 1;
 +	if (done_pbase_paths_alloc <= done_pbase_paths_num) {
 +		done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
 +		done_pbase_paths = xrealloc(done_pbase_paths,
 +					    done_pbase_paths_alloc *
 +					    sizeof(unsigned));
 +	}
 +	done_pbase_paths_num++;
 +	if (pos < done_pbase_paths_num)
 +		memmove(done_pbase_paths + pos + 1,
 +			done_pbase_paths + pos,
 +			(done_pbase_paths_num - pos - 1) * sizeof(unsigned));
 +	done_pbase_paths[pos] = hash;
 +	return 0;
 +}
 +
 +static void add_preferred_base_object(char *name, unsigned hash)
 +{
 +	struct pbase_tree *it;
 +	int cmplen = name_cmp_len(name);
 +
 +	if (check_pbase_path(hash))
 +		return;
 +
 +	for (it = pbase_tree; it; it = it->next) {
 +		if (cmplen == 0) {
 +			hash = name_hash("");
 +			add_object_entry(it->pcache.sha1, hash, 1);
 +		}
 +		else {
 +			struct tree_desc tree;
 +			tree.buf = it->pcache.tree_data;
 +			tree.size = it->pcache.tree_size;
 +			add_pbase_object(&tree, name, cmplen, name);
 +		}
 +	}
 +}
 +
 +static void add_preferred_base(unsigned char *sha1)
 +{
 +	struct pbase_tree *it;
 +	void *data;
 +	unsigned long size;
 +	unsigned char tree_sha1[20];
 +
 +	data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
 +	if (!data)
 +		return;
 +
 +	for (it = pbase_tree; it; it = it->next) {
 +		if (!memcmp(it->pcache.sha1, tree_sha1, 20)) {
 +			free(data);
 +			return;
 +		}
 +	}
 +
 +	it = xcalloc(1, sizeof(*it));
 +	it->next = pbase_tree;
 +	pbase_tree = it;
 +
 +	memcpy(it->pcache.sha1, tree_sha1, 20);
 +	it->pcache.tree_data = data;
 +	it->pcache.tree_size = size;
 +}
 +
 +static void check_object(struct object_entry *entry)
 +{
 +	char type[20];
 +
 +	if (entry->in_pack && !entry->preferred_base) {
 +		unsigned char base[20];
 +		unsigned long size;
 +		struct object_entry *base_entry;
 +
 +		/* We want in_pack_type even if we do not reuse delta.
 +		 * There is no point not reusing non-delta representations.
 +		 */
 +		check_reuse_pack_delta(entry->in_pack,
 +				       entry->in_pack_offset,
 +				       base, &size,
 +				       &entry->in_pack_type);
 +
 +		/* Check if it is delta, and the base is also an object
 +		 * we are going to pack.  If so we will reuse the existing
 +		 * delta.
 +		 */
 +		if (!no_reuse_delta &&
 +		    entry->in_pack_type == OBJ_DELTA &&
 +		    (base_entry = locate_object_entry(base)) &&
 +		    (!base_entry->preferred_base)) {
 +
 +			/* Depth value does not matter - find_deltas()
 +			 * will never consider reused delta as the
 +			 * base object to deltify other objects
 +			 * against, in order to avoid circular deltas.
 +			 */
 +
 +			/* uncompressed size of the delta data */
 +			entry->size = entry->delta_size = size;
 +			entry->delta = base_entry;
 +			entry->type = OBJ_DELTA;
 +
 +			entry->delta_sibling = base_entry->delta_child;
 +			base_entry->delta_child = entry;
 +
 +			return;
 +		}
 +		/* Otherwise we would do the usual */
 +	}
 +
 +	if (sha1_object_info(entry->sha1, type, &entry->size))
 +		die("unable to get type of object %s",
 +		    sha1_to_hex(entry->sha1));
 +
 +	if (!strcmp(type, commit_type)) {
 +		entry->type = OBJ_COMMIT;
 +	} else if (!strcmp(type, tree_type)) {
 +		entry->type = OBJ_TREE;
 +	} else if (!strcmp(type, blob_type)) {
 +		entry->type = OBJ_BLOB;
 +	} else if (!strcmp(type, tag_type)) {
 +		entry->type = OBJ_TAG;
 +	} else
 +		die("unable to pack object %s of type %s",
 +		    sha1_to_hex(entry->sha1), type);
 +}
 +
 +static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
 +{
 +	struct object_entry *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 void get_object_details(void)
 +{
 +	int i;
 +	struct object_entry *entry;
 +
 +	prepare_pack_ix();
 +	for (i = 0, entry = objects; i < nr_objects; i++, entry++)
 +		check_object(entry);
 +
 +	if (nr_objects == nr_result) {
 +		/*
 +		 * Depth of objects that depend on the entry -- this
 +		 * is subtracted from depth-max to break too deep
 +		 * delta chain because of delta data reusing.
 +		 * However, we loosen this restriction when we know we
 +		 * are creating a thin pack -- it will have to be
 +		 * expanded on the other end anyway, so do not
 +		 * artificially cut the delta chain and let it go as
 +		 * deep as it wants.
 +		 */
 +		for (i = 0, entry = objects; i < nr_objects; i++, entry++)
 +			if (!entry->delta && entry->delta_child)
 +				entry->delta_limit =
 +					check_delta_limit(entry, 1);
 +	}
 +}
 +
 +typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
 +
 +static entry_sort_t current_sort;
 +
 +static int sort_comparator(const void *_a, const void *_b)
 +{
 +	struct object_entry *a = *(struct object_entry **)_a;
 +	struct object_entry *b = *(struct object_entry **)_b;
 +	return current_sort(a,b);
 +}
 +
 +static struct object_entry **create_sorted_list(entry_sort_t sort)
 +{
 +	struct object_entry **list = xmalloc(nr_objects * sizeof(struct object_entry *));
 +	int i;
 +
 +	for (i = 0; i < nr_objects; i++)
 +		list[i] = objects + i;
 +	current_sort = sort;
 +	qsort(list, nr_objects, sizeof(struct object_entry *), sort_comparator);
 +	return list;
 +}
 +
 +static int sha1_sort(const struct object_entry *a, const struct object_entry *b)
 +{
 +	return memcmp(a->sha1, b->sha1, 20);
 +}
 +
 +static struct object_entry **create_final_object_list(void)
 +{
 +	struct object_entry **list;
 +	int i, j;
 +
 +	for (i = nr_result = 0; i < nr_objects; i++)
 +		if (!objects[i].preferred_base)
 +			nr_result++;
 +	list = xmalloc(nr_result * sizeof(struct object_entry *));
 +	for (i = j = 0; i < nr_objects; i++) {
 +		if (!objects[i].preferred_base)
 +			list[j++] = objects + i;
 +	}
 +	current_sort = sha1_sort;
 +	qsort(list, nr_result, sizeof(struct object_entry *), sort_comparator);
 +	return list;
 +}
 +
 +static int type_size_sort(const struct object_entry *a, const struct object_entry *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;
 +	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);
 +}
 +
 +struct unpacked {
 +	struct object_entry *entry;
 +	void *data;
 +	struct delta_index *index;
 +};
 +
 +/*
 + * We search for deltas _backwards_ in a list sorted by type and
 + * by size, so that we see progressively smaller and smaller files.
 + * That's because we prefer deltas to be from the bigger file
 + * to the smaller - deletes are potentially cheaper, but perhaps
 + * more importantly, the bigger file is likely the more recent
 + * one.
 + */
 +static int try_delta(struct unpacked *trg, struct unpacked *src,
 +		     unsigned max_depth)
 +{
 +	struct object_entry *trg_entry = trg->entry;
 +	struct object_entry *src_entry = src->entry;
 +	unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
 +	char type[10];
 +	void *delta_buf;
 +
 +	/* Don't bother doing diffs between different types */
 +	if (trg_entry->type != src_entry->type)
 +		return -1;
 +
 +	/* We do not compute delta to *create* objects we are not
 +	 * going to pack.
 +	 */
 +	if (trg_entry->preferred_base)
 +		return -1;
 +
 +	/*
 +	 * We do not bother to try a delta that we discarded
 +	 * on an earlier try, but only when reusing delta data.
 +	 */
 +	if (!no_reuse_delta && trg_entry->in_pack &&
 +	    trg_entry->in_pack == src_entry->in_pack)
 +		return 0;
 +
 +	/*
 +	 * 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.
 +	 */
 +	if (trg_entry->delta_child) {
 +		if (max_depth <= trg_entry->delta_limit)
 +			return 0;
 +		max_depth -= trg_entry->delta_limit;
 +	}
 +	if (src_entry->depth >= max_depth)
 +		return 0;
 +
 +	/* Now some size filtering heuristics. */
 +	trg_size = trg_entry->size;
 +	max_size = trg_size/2 - 20;
 +	max_size = max_size * (max_depth - src_entry->depth) / max_depth;
 +	if (max_size == 0)
 +		return 0;
 +	if (trg_entry->delta && trg_entry->delta_size <= max_size)
 +		max_size = trg_entry->delta_size-1;
 +	src_size = src_entry->size;
 +	sizediff = src_size < trg_size ? trg_size - src_size : 0;
 +	if (sizediff >= max_size)
 +		return 0;
 +
 +	/* Load data if not already done */
 +	if (!trg->data) {
 +		trg->data = read_sha1_file(trg_entry->sha1, type, &sz);
 +		if (sz != trg_size)
 +			die("object %s inconsistent object length (%lu vs %lu)",
 +			    sha1_to_hex(trg_entry->sha1), sz, trg_size);
 +	}
 +	if (!src->data) {
 +		src->data = read_sha1_file(src_entry->sha1, type, &sz);
 +		if (sz != src_size)
 +			die("object %s inconsistent object length (%lu vs %lu)",
 +			    sha1_to_hex(src_entry->sha1), sz, src_size);
 +	}
 +	if (!src->index) {
 +		src->index = create_delta_index(src->data, src_size);
 +		if (!src->index)
 +			die("out of memory");
 +	}
 +
 +	delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
 +	if (!delta_buf)
 +		return 0;
 +
 +	trg_entry->delta = src_entry;
 +	trg_entry->delta_size = delta_size;
 +	trg_entry->depth = src_entry->depth + 1;
 +	free(delta_buf);
 +	return 1;
 +}
 +
 +static void progress_interval(int signum)
 +{
 +	progress_update = 1;
 +}
 +
 +static void find_deltas(struct object_entry **list, int window, int depth)
 +{
 +	int i, idx;
 +	unsigned int array_size = window * sizeof(struct unpacked);
 +	struct unpacked *array = xmalloc(array_size);
 +	unsigned processed = 0;
 +	unsigned last_percent = 999;
 +
 +	memset(array, 0, array_size);
 +	i = nr_objects;
 +	idx = 0;
 +	if (progress)
 +		fprintf(stderr, "Deltifying %d objects.\n", nr_result);
 +
 +	while (--i >= 0) {
 +		struct object_entry *entry = list[i];
 +		struct unpacked *n = array + idx;
 +		int j;
 +
 +		if (!entry->preferred_base)
 +			processed++;
 +
 +		if (progress) {
 +			unsigned percent = processed * 100 / nr_result;
 +			if (percent != last_percent || progress_update) {
 +				fprintf(stderr, "%4u%% (%u/%u) done\r",
 +					percent, processed, nr_result);
 +				progress_update = 0;
 +				last_percent = percent;
 +			}
 +		}
 +
 +		if (entry->delta)
 +			/* This happens if we decided to reuse existing
 +			 * delta from a pack.  "!no_reuse_delta &&" is implied.
 +			 */
 +			continue;
 +
 +		if (entry->size < 50)
 +			continue;
 +		free_delta_index(n->index);
 +		n->index = NULL;
 +		free(n->data);
 +		n->data = NULL;
 +		n->entry = entry;
 +
 +		j = window;
 +		while (--j > 0) {
 +			unsigned int other_idx = idx + j;
 +			struct unpacked *m;
 +			if (other_idx >= window)
 +				other_idx -= window;
 +			m = array + other_idx;
 +			if (!m->entry)
 +				break;
 +			if (try_delta(n, m, depth) < 0)
 +				break;
 +		}
 +		/* 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 (entry->delta && depth <= entry->depth)
 +			continue;
 +
 +		idx++;
 +		if (idx >= window)
 +			idx = 0;
 +	}
 +
 +	if (progress)
 +		fputc('\n', stderr);
 +
 +	for (i = 0; i < window; ++i) {
 +		free_delta_index(array[i].index);
 +		free(array[i].data);
 +	}
 +	free(array);
 +}
 +
 +static void prepare_pack(int window, int depth)
 +{
 +	get_object_details();
 +	sorted_by_type = create_sorted_list(type_size_sort);
 +	if (window && depth)
 +		find_deltas(sorted_by_type, window+1, depth);
 +}
 +
 +static int reuse_cached_pack(unsigned char *sha1, int pack_to_stdout)
 +{
 +	static const char cache[] = "pack-cache/pack-%s.%s";
 +	char *cached_pack, *cached_idx;
 +	int ifd, ofd, ifd_ix = -1;
 +
 +	cached_pack = git_path(cache, sha1_to_hex(sha1), "pack");
 +	ifd = open(cached_pack, O_RDONLY);
 +	if (ifd < 0)
 +		return 0;
 +
 +	if (!pack_to_stdout) {
 +		cached_idx = git_path(cache, sha1_to_hex(sha1), "idx");
 +		ifd_ix = open(cached_idx, O_RDONLY);
 +		if (ifd_ix < 0) {
 +			close(ifd);
 +			return 0;
 +		}
 +	}
 +
 +	if (progress)
 +		fprintf(stderr, "Reusing %d objects pack %s\n", nr_objects,
 +			sha1_to_hex(sha1));
 +
 +	if (pack_to_stdout) {
 +		if (copy_fd(ifd, 1))
 +			exit(1);
 +		close(ifd);
 +	}
 +	else {
 +		char name[PATH_MAX];
 +		snprintf(name, sizeof(name),
 +			 "%s-%s.%s", base_name, sha1_to_hex(sha1), "pack");
 +		ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
 +		if (ofd < 0)
 +			die("unable to open %s (%s)", name, strerror(errno));
 +		if (copy_fd(ifd, ofd))
 +			exit(1);
 +		close(ifd);
 +
 +		snprintf(name, sizeof(name),
 +			 "%s-%s.%s", base_name, sha1_to_hex(sha1), "idx");
 +		ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
 +		if (ofd < 0)
 +			die("unable to open %s (%s)", name, strerror(errno));
 +		if (copy_fd(ifd_ix, ofd))
 +			exit(1);
 +		close(ifd_ix);
 +		puts(sha1_to_hex(sha1));
 +	}
 +
 +	return 1;
 +}
 +
 +static void setup_progress_signal(void)
 +{
 +	struct sigaction sa;
 +	struct itimerval v;
 +
 +	memset(&sa, 0, sizeof(sa));
 +	sa.sa_handler = progress_interval;
 +	sigemptyset(&sa.sa_mask);
 +	sa.sa_flags = SA_RESTART;
 +	sigaction(SIGALRM, &sa, NULL);
 +
 +	v.it_interval.tv_sec = 1;
 +	v.it_interval.tv_usec = 0;
 +	v.it_value = v.it_interval;
 +	setitimer(ITIMER_REAL, &v, NULL);
 +}
 +
 +static int git_pack_config(const char *k, const char *v)
 +{
 +	if(!strcmp(k, "pack.window")) {
 +		window = git_config_int(k, v);
 +		return 0;
 +	}
 +	return git_default_config(k, v);
 +}
 +
 +int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 +{
 +	SHA_CTX ctx;
 +	char line[40 + 1 + PATH_MAX + 2];
 +	int depth = 10, pack_to_stdout = 0;
 +	struct object_entry **list;
 +	int num_preferred_base = 0;
 +	int i;
 +
 +	git_config(git_pack_config);
 +
 +	progress = isatty(2);
 +	for (i = 1; i < argc; i++) {
 +		const char *arg = argv[i];
 +
 +		if (*arg == '-') {
 +			if (!strcmp("--non-empty", arg)) {
 +				non_empty = 1;
 +				continue;
 +			}
 +			if (!strcmp("--local", arg)) {
 +				local = 1;
 +				continue;
 +			}
 +			if (!strcmp("--progress", arg)) {
 +				progress = 1;
 +				continue;
 +			}
 +			if (!strcmp("--incremental", arg)) {
 +				incremental = 1;
 +				continue;
 +			}
 +			if (!strncmp("--window=", arg, 9)) {
 +				char *end;
 +				window = strtoul(arg+9, &end, 0);
 +				if (!arg[9] || *end)
 +					usage(pack_usage);
 +				continue;
 +			}
 +			if (!strncmp("--depth=", arg, 8)) {
 +				char *end;
 +				depth = strtoul(arg+8, &end, 0);
 +				if (!arg[8] || *end)
 +					usage(pack_usage);
 +				continue;
 +			}
 +			if (!strcmp("--progress", arg)) {
 +				progress = 1;
 +				continue;
 +			}
 +			if (!strcmp("-q", arg)) {
 +				progress = 0;
 +				continue;
 +			}
 +			if (!strcmp("--no-reuse-delta", arg)) {
 +				no_reuse_delta = 1;
 +				continue;
 +			}
 +			if (!strcmp("--stdout", arg)) {
 +				pack_to_stdout = 1;
 +				continue;
 +			}
 +			usage(pack_usage);
 +		}
 +		if (base_name)
 +			usage(pack_usage);
 +		base_name = arg;
 +	}
 +
 +	if (pack_to_stdout != !base_name)
 +		usage(pack_usage);
 +
 +	prepare_packed_git();
 +
 +	if (progress) {
 +		fprintf(stderr, "Generating pack...\n");
 +		setup_progress_signal();
 +	}
 +
 +	for (;;) {
 +		unsigned char sha1[20];
 +		unsigned hash;
 +
 +		if (!fgets(line, sizeof(line), stdin)) {
 +			if (feof(stdin))
 +				break;
 +			if (!ferror(stdin))
 +				die("fgets returned NULL, not EOF, not error!");
 +			if (errno != EINTR)
 +				die("fgets: %s", strerror(errno));
 +			clearerr(stdin);
 +			continue;
 +		}
 +
 +		if (line[0] == '-') {
 +			if (get_sha1_hex(line+1, sha1))
 +				die("expected edge sha1, got garbage:\n %s",
 +				    line+1);
 +			if (num_preferred_base++ < window)
 +				add_preferred_base(sha1);
 +			continue;
 +		}
 +		if (get_sha1_hex(line, sha1))
 +			die("expected sha1, got garbage:\n %s", line);
 +		hash = name_hash(line+41);
 +		add_preferred_base_object(line+41, hash);
 +		add_object_entry(sha1, hash, 0);
 +	}
 +	if (progress)
 +		fprintf(stderr, "Done counting %d objects.\n", nr_objects);
 +	sorted_by_sha = create_final_object_list();
 +	if (non_empty && !nr_result)
 +		return 0;
 +
 +	SHA1_Init(&ctx);
 +	list = sorted_by_sha;
 +	for (i = 0; i < nr_result; i++) {
 +		struct object_entry *entry = *list++;
 +		SHA1_Update(&ctx, entry->sha1, 20);
 +	}
 +	SHA1_Final(object_list_sha1, &ctx);
 +	if (progress && (nr_objects != nr_result))
 +		fprintf(stderr, "Result has %d objects.\n", nr_result);
 +
 +	if (reuse_cached_pack(object_list_sha1, pack_to_stdout))
 +		;
 +	else {
 +		if (nr_result)
 +			prepare_pack(window, depth);
 +		if (progress && pack_to_stdout) {
 +			/* the other end usually displays progress itself */
 +			struct itimerval v = {{0,},};
 +			setitimer(ITIMER_REAL, &v, NULL);
 +			signal(SIGALRM, SIG_IGN );
 +			progress_update = 0;
 +		}
 +		write_pack_file();
 +		if (!pack_to_stdout) {
 +			write_index_file();
 +			puts(sha1_to_hex(object_list_sha1));
 +		}
 +	}
 +	if (progress)
 +		fprintf(stderr, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
 +			nr_result, written, written_delta, reused, reused_delta);
 +	return 0;
 +}
diff --cc builtin-unpack-objects.c
index 09d264d9f,000000000..63f4b8e45
mode 100644,000000..100644
--- a/builtin-unpack-objects.c
+++ b/builtin-unpack-objects.c
@@@ -1,310 -1,0 +1,312 @@@
 +#include "builtin.h"
 +#include "cache.h"
 +#include "object.h"
 +#include "delta.h"
 +#include "pack.h"
 +#include "blob.h"
 +#include "commit.h"
 +#include "tag.h"
 +#include "tree.h"
 +
 +#include <sys/time.h>
 +
 +static int dry_run, quiet;
 +static const char unpack_usage[] = "git-unpack-objects [-n] [-q] < pack-file";
 +
 +/* We always read in 4kB chunks. */
 +static unsigned char buffer[4096];
 +static unsigned long offset, len, eof;
 +static SHA_CTX ctx;
 +
 +/*
 + * Make sure at least "min" bytes are available in the buffer, and
 + * return the pointer to the buffer.
 + */
 +static void * fill(int min)
 +{
 +	if (min <= len)
 +		return buffer + offset;
 +	if (eof)
 +		die("unable to fill input");
 +	if (min > sizeof(buffer))
 +		die("cannot fill %d bytes", min);
 +	if (offset) {
 +		SHA1_Update(&ctx, buffer, offset);
 +		memcpy(buffer, buffer + offset, len);
 +		offset = 0;
 +	}
 +	do {
 +		int ret = xread(0, buffer + len, sizeof(buffer) - len);
 +		if (ret <= 0) {
 +			if (!ret)
 +				die("early EOF");
 +			die("read error on input: %s", strerror(errno));
 +		}
 +		len += ret;
 +	} while (len < min);
 +	return buffer;
 +}
 +
 +static void use(int bytes)
 +{
 +	if (bytes > len)
 +		die("used more bytes than were available");
 +	len -= bytes;
 +	offset += bytes;
 +}
 +
 +static void *get_data(unsigned long size)
 +{
 +	z_stream stream;
 +	void *buf = xmalloc(size);
 +
 +	memset(&stream, 0, sizeof(stream));
 +
 +	stream.next_out = buf;
 +	stream.avail_out = size;
 +	stream.next_in = fill(1);
 +	stream.avail_in = len;
 +	inflateInit(&stream);
 +
 +	for (;;) {
 +		int ret = inflate(&stream, 0);
 +		use(len - stream.avail_in);
 +		if (stream.total_out == size && ret == Z_STREAM_END)
 +			break;
 +		if (ret != Z_OK)
 +			die("inflate returned %d\n", ret);
 +		stream.next_in = fill(1);
 +		stream.avail_in = len;
 +	}
 +	inflateEnd(&stream);
 +	return buf;
 +}
 +
 +struct delta_info {
 +	unsigned char base_sha1[20];
 +	unsigned long size;
 +	void *delta;
 +	struct delta_info *next;
 +};
 +
 +static struct delta_info *delta_list;
 +
 +static void add_delta_to_list(unsigned char *base_sha1, void *delta, unsigned long size)
 +{
 +	struct delta_info *info = xmalloc(sizeof(*info));
 +
 +	memcpy(info->base_sha1, base_sha1, 20);
 +	info->size = size;
 +	info->delta = delta;
 +	info->next = delta_list;
 +	delta_list = info;
 +}
 +
 +static void added_object(unsigned char *sha1, const char *type, void *data, unsigned long size);
 +
 +static void write_object(void *buf, unsigned long size, const char *type)
 +{
 +	unsigned char sha1[20];
 +	if (write_sha1_file(buf, size, type, sha1) < 0)
 +		die("failed to write object");
 +	added_object(sha1, type, buf, size);
 +}
 +
 +static int resolve_delta(const char *type,
 +	void *base, unsigned long base_size,
 +	void *delta, unsigned long delta_size)
 +{
 +	void *result;
 +	unsigned long result_size;
 +
 +	result = patch_delta(base, base_size,
 +			     delta, delta_size,
 +			     &result_size);
 +	if (!result)
 +		die("failed to apply delta");
 +	free(delta);
 +	write_object(result, result_size, type);
 +	free(result);
 +	return 0;
 +}
 +
 +static void added_object(unsigned char *sha1, const char *type, void *data, unsigned long size)
 +{
 +	struct delta_info **p = &delta_list;
 +	struct delta_info *info;
 +
 +	while ((info = *p) != NULL) {
 +		if (!memcmp(info->base_sha1, sha1, 20)) {
 +			*p = info->next;
 +			p = &delta_list;
 +			resolve_delta(type, data, size, info->delta, info->size);
 +			free(info);
 +			continue;
 +		}
 +		p = &info->next;
 +	}
 +}
 +
 +static int unpack_non_delta_entry(enum object_type kind, unsigned long size)
 +{
 +	void *buf = get_data(size);
 +	const char *type;
 +
 +	switch (kind) {
 +	case OBJ_COMMIT: type = commit_type; break;
 +	case OBJ_TREE:   type = tree_type; break;
 +	case OBJ_BLOB:   type = blob_type; break;
 +	case OBJ_TAG:    type = tag_type; break;
 +	default: die("bad type %d", kind);
 +	}
 +	if (!dry_run)
 +		write_object(buf, size, type);
 +	free(buf);
 +	return 0;
 +}
 +
 +static int unpack_delta_entry(unsigned long delta_size)
 +{
 +	void *delta_data, *base;
 +	unsigned long base_size;
 +	char type[20];
 +	unsigned char base_sha1[20];
 +	int result;
 +
 +	memcpy(base_sha1, fill(20), 20);
 +	use(20);
 +
 +	delta_data = get_data(delta_size);
 +	if (dry_run) {
 +		free(delta_data);
 +		return 0;
 +	}
 +
 +	if (!has_sha1_file(base_sha1)) {
 +		add_delta_to_list(base_sha1, delta_data, delta_size);
 +		return 0;
 +	}
 +	base = read_sha1_file(base_sha1, type, &base_size);
 +	if (!base)
 +		die("failed to read delta-pack base object %s", sha1_to_hex(base_sha1));
 +	result = resolve_delta(type, base, base_size, delta_data, delta_size);
 +	free(base);
 +	return result;
 +}
 +
 +static void unpack_one(unsigned nr, unsigned total)
 +{
 +	unsigned shift;
 +	unsigned char *pack, c;
 +	unsigned long size;
 +	enum object_type type;
 +
 +	pack = fill(1);
 +	c = *pack;
 +	use(1);
 +	type = (c >> 4) & 7;
 +	size = (c & 15);
 +	shift = 4;
 +	while (c & 0x80) {
 +		pack = fill(1);
 +		c = *pack++;
 +		use(1);
 +		size += (c & 0x7f) << shift;
 +		shift += 7;
 +	}
 +	if (!quiet) {
 +		static unsigned long last_sec;
 +		static unsigned last_percent;
 +		struct timeval now;
 +		unsigned percentage = (nr * 100) / total;
 +
 +		gettimeofday(&now, NULL);
 +		if (percentage != last_percent || now.tv_sec != last_sec) {
 +			last_sec = now.tv_sec;
 +			last_percent = percentage;
 +			fprintf(stderr, "%4u%% (%u/%u) done\r", percentage, nr, total);
 +		}
 +	}
 +	switch (type) {
 +	case OBJ_COMMIT:
 +	case OBJ_TREE:
 +	case OBJ_BLOB:
 +	case OBJ_TAG:
 +		unpack_non_delta_entry(type, size);
 +		return;
 +	case OBJ_DELTA:
 +		unpack_delta_entry(size);
 +		return;
 +	default:
 +		die("bad object type %d", type);
 +	}
 +}
 +
 +static void unpack_all(void)
 +{
 +	int i;
 +	struct pack_header *hdr = fill(sizeof(struct pack_header));
 +	unsigned nr_objects = ntohl(hdr->hdr_entries);
 +
 +	if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
 +		die("bad pack file");
 +	if (!pack_version_ok(hdr->hdr_version))
 +		die("unknown pack file version %d", ntohl(hdr->hdr_version));
 +	fprintf(stderr, "Unpacking %d objects\n", nr_objects);
 +
 +	use(sizeof(struct pack_header));
 +	for (i = 0; i < nr_objects; i++)
 +		unpack_one(i+1, nr_objects);
 +	if (delta_list)
 +		die("unresolved deltas left after unpacking");
 +}
 +
 +int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
 +{
 +	int i;
 +	unsigned char sha1[20];
 +
++	git_config(git_default_config);
++
 +	quiet = !isatty(2);
 +
 +	for (i = 1 ; i < argc; i++) {
 +		const char *arg = argv[i];
 +
 +		if (*arg == '-') {
 +			if (!strcmp(arg, "-n")) {
 +				dry_run = 1;
 +				continue;
 +			}
 +			if (!strcmp(arg, "-q")) {
 +				quiet = 1;
 +				continue;
 +			}
 +			usage(unpack_usage);
 +		}
 +
 +		/* We don't take any non-flag arguments now.. Maybe some day */
 +		usage(unpack_usage);
 +	}
 +	SHA1_Init(&ctx);
 +	unpack_all();
 +	SHA1_Update(&ctx, buffer, offset);
 +	SHA1_Final(sha1, &ctx);
 +	if (memcmp(fill(20), sha1, 20))
 +		die("final sha1 did not match");
 +	use(20);
 +
 +	/* Write the last part of the buffer to stdout */
 +	while (len) {
 +		int ret = xwrite(1, buffer + offset, len);
 +		if (ret <= 0)
 +			break;
 +		len -= ret;
 +		offset += ret;
 +	}
 +
 +	/* All done */
 +	if (!quiet)
 +		fprintf(stderr, "\n");
 +	return 0;
 +}