Make git-pack-objects a builtin

Signed-off-by: Matthias Kestenholz <matthias@spinlock.ch>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 0 insertions, 1376 deletions

diff --git a/pack-objects.c b/pack-objects.c
deleted file mode 100644
index 861c7f0..0000000
--- a/pack-objects.c
+++ /dev/null
@@ -1,1376 +0,0 @@
-#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 (! 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 main(int argc, char **argv)
-{
-	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;
-
-	setup_git_directory();
-	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;
-}