Merge "Move 'builtin-*' into a 'builtin/' subdirectory"

1 files changed, 2375 insertions, 0 deletions

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
new file mode 100644
index 0000000000..e1d3adf405
--- /dev/null
+++ b/builtin/pack-objects.c
@@ -0,0 +1,2375 @@
+#include "builtin.h"
+#include "cache.h"
+#include "attr.h"
+#include "object.h"
+#include "blob.h"
+#include "commit.h"
+#include "tag.h"
+#include "tree.h"
+#include "delta.h"
+#include "pack.h"
+#include "pack-revindex.h"
+#include "csum-file.h"
+#include "tree-walk.h"
+#include "diff.h"
+#include "revision.h"
+#include "list-objects.h"
+#include "progress.h"
+#include "refs.h"
+
+#ifndef NO_PTHREADS
+#include "thread-utils.h"
+#include <pthread.h>
+#endif
+
+static const char pack_usage[] =
+  "git pack-objects [{ -q | --progress | --all-progress }]\n"
+  "        [--all-progress-implied]\n"
+  "        [--max-pack-size=N] [--local] [--incremental]\n"
+  "        [--window=N] [--window-memory=N] [--depth=N]\n"
+  "        [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset]\n"
+  "        [--threads=N] [--non-empty] [--revs [--unpacked | --all]*]\n"
+  "        [--reflog] [--stdout | base-name] [--include-tag]\n"
+  "        [--keep-unreachable | --unpack-unreachable \n"
+  "        [<ref-list | <object-list]";
+
+struct object_entry {
+	struct pack_idx_entry idx;
+	unsigned long size;	/* uncompressed size */
+	struct packed_git *in_pack; 	/* already in pack */
+	off_t in_pack_offset;
+	struct object_entry *delta;	/* delta base object */
+	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
+					     */
+	void *delta_data;	/* cached delta (uncompressed) */
+	unsigned long delta_size;	/* delta data size (uncompressed) */
+	unsigned long z_delta_size;	/* delta data size (compressed) */
+	unsigned int hash;	/* name hint hash */
+	enum object_type type;
+	enum object_type in_pack_type;	/* could be delta */
+	unsigned char in_pack_header_size;
+	unsigned char preferred_base; /* we do not pack this, but is available
+				       * to be used as the base object to delta
+				       * objects against.
+				       */
+	unsigned char no_try_delta;
+};
+
+/*
+ * 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.
+ */
+static struct object_entry *objects;
+static struct pack_idx_entry **written_list;
+static uint32_t nr_objects, nr_alloc, nr_result, nr_written;
+
+static int non_empty;
+static int reuse_delta = 1, reuse_object = 1;
+static int keep_unreachable, unpack_unreachable, include_tag;
+static int local;
+static int incremental;
+static int ignore_packed_keep;
+static int allow_ofs_delta;
+static const char *base_name;
+static int progress = 1;
+static int window = 10;
+static unsigned long pack_size_limit, pack_size_limit_cfg;
+static int depth = 50;
+static int delta_search_threads;
+static int pack_to_stdout;
+static int num_preferred_base;
+static struct progress *progress_state;
+static int pack_compression_level = Z_DEFAULT_COMPRESSION;
+static int pack_compression_seen;
+
+static unsigned long delta_cache_size = 0;
+static unsigned long max_delta_cache_size = 256 * 1024 * 1024;
+static unsigned long cache_max_small_delta_size = 1000;
+
+static unsigned long window_memory_limit = 0;
+
+/*
+ * The object names in objects array are hashed with this hashtable,
+ * to help looking up the entry by object name.
+ * This hashtable is built after all the objects are seen.
+ */
+static int *object_ix;
+static int object_ix_hashsz;
+
+/*
+ * stats
+ */
+static uint32_t written, written_delta;
+static uint32_t reused, reused_delta;
+
+
+static void *get_delta(struct object_entry *entry)
+{
+	unsigned long size, base_size, delta_size;
+	void *buf, *base_buf, *delta_buf;
+	enum object_type type;
+
+	buf = read_sha1_file(entry->idx.sha1, &type, &size);
+	if (!buf)
+		die("unable to read %s", sha1_to_hex(entry->idx.sha1));
+	base_buf = read_sha1_file(entry->delta->idx.sha1, &type, &base_size);
+	if (!base_buf)
+		die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
+	delta_buf = diff_delta(base_buf, base_size,
+			       buf, size, &delta_size, 0);
+	if (!delta_buf || delta_size != entry->delta_size)
+		die("delta size changed");
+	free(buf);
+	free(base_buf);
+	return delta_buf;
+}
+
+static unsigned long do_compress(void **pptr, unsigned long size)
+{
+	z_stream stream;
+	void *in, *out;
+	unsigned long maxsize;
+
+	memset(&stream, 0, sizeof(stream));
+	deflateInit(&stream, pack_compression_level);
+	maxsize = deflateBound(&stream, size);
+
+	in = *pptr;
+	out = xmalloc(maxsize);
+	*pptr = out;
+
+	stream.next_in = in;
+	stream.avail_in = size;
+	stream.next_out = out;
+	stream.avail_out = maxsize;
+	while (deflate(&stream, Z_FINISH) == Z_OK)
+		; /* nothing */
+	deflateEnd(&stream);
+
+	free(in);
+	return stream.total_out;
+}
+
+/*
+ * 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_REF_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;
+}
+
+/*
+ * we are going to reuse the existing object data as is.  make
+ * sure it is not corrupt.
+ */
+static int check_pack_inflate(struct packed_git *p,
+		struct pack_window **w_curs,
+		off_t offset,
+		off_t len,
+		unsigned long expect)
+{
+	z_stream stream;
+	unsigned char fakebuf[4096], *in;
+	int st;
+
+	memset(&stream, 0, sizeof(stream));
+	git_inflate_init(&stream);
+	do {
+		in = use_pack(p, w_curs, offset, &stream.avail_in);
+		stream.next_in = in;
+		stream.next_out = fakebuf;
+		stream.avail_out = sizeof(fakebuf);
+		st = git_inflate(&stream, Z_FINISH);
+		offset += stream.next_in - in;
+	} while (st == Z_OK || st == Z_BUF_ERROR);
+	git_inflate_end(&stream);
+	return (st == Z_STREAM_END &&
+		stream.total_out == expect &&
+		stream.total_in == len) ? 0 : -1;
+}
+
+static void copy_pack_data(struct sha1file *f,
+		struct packed_git *p,
+		struct pack_window **w_curs,
+		off_t offset,
+		off_t len)
+{
+	unsigned char *in;
+	unsigned int avail;
+
+	while (len) {
+		in = use_pack(p, w_curs, offset, &avail);
+		if (avail > len)
+			avail = (unsigned int)len;
+		sha1write(f, in, avail);
+		offset += avail;
+		len -= avail;
+	}
+}
+
+static unsigned long write_object(struct sha1file *f,
+				  struct object_entry *entry,
+				  off_t write_offset)
+{
+	unsigned long size, limit, datalen;
+	void *buf;
+	unsigned char header[10], dheader[10];
+	unsigned hdrlen;
+	enum object_type type;
+	int usable_delta, to_reuse;
+
+	if (!pack_to_stdout)
+		crc32_begin(f);
+
+	type = entry->type;
+
+	/* apply size limit if limited packsize and not first object */
+	if (!pack_size_limit || !nr_written)
+		limit = 0;
+	else if (pack_size_limit <= write_offset)
+		/*
+		 * the earlier object did not fit the limit; avoid
+		 * mistaking this with unlimited (i.e. limit = 0).
+		 */
+		limit = 1;
+	else
+		limit = pack_size_limit - write_offset;
+
+	if (!entry->delta)
+		usable_delta = 0;	/* no delta */
+	else if (!pack_size_limit)
+	       usable_delta = 1;	/* unlimited packfile */
+	else if (entry->delta->idx.offset == (off_t)-1)
+		usable_delta = 0;	/* base was written to another pack */
+	else if (entry->delta->idx.offset)
+		usable_delta = 1;	/* base already exists in this pack */
+	else
+		usable_delta = 0;	/* base could end up in another pack */
+
+	if (!reuse_object)
+		to_reuse = 0;	/* explicit */
+	else if (!entry->in_pack)
+		to_reuse = 0;	/* can't reuse what we don't have */
+	else if (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA)
+				/* check_object() decided it for us ... */
+		to_reuse = usable_delta;
+				/* ... but pack split may override that */
+	else if (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) {
+		no_reuse:
+		if (!usable_delta) {
+			buf = read_sha1_file(entry->idx.sha1, &type, &size);
+			if (!buf)
+				die("unable to read %s", sha1_to_hex(entry->idx.sha1));
+			/*
+			 * make sure no cached delta data remains from a
+			 * previous attempt before a pack split occurred.
+			 */
+			free(entry->delta_data);
+			entry->delta_data = NULL;
+			entry->z_delta_size = 0;
+		} else if (entry->delta_data) {
+			size = entry->delta_size;
+			buf = entry->delta_data;
+			entry->delta_data = NULL;
+			type = (allow_ofs_delta && entry->delta->idx.offset) ?
+				OBJ_OFS_DELTA : OBJ_REF_DELTA;
+		} else {
+			buf = get_delta(entry);
+			size = entry->delta_size;
+			type = (allow_ofs_delta && entry->delta->idx.offset) ?
+				OBJ_OFS_DELTA : OBJ_REF_DELTA;
+		}
+
+		if (entry->z_delta_size)
+			datalen = entry->z_delta_size;
+		else
+			datalen = do_compress(&buf, size);
+
+		/*
+		 * The object header is a byte of 'type' followed by zero or
+		 * more bytes of length.
+		 */
+		hdrlen = encode_header(type, size, header);
+
+		if (type == OBJ_OFS_DELTA) {
+			/*
+			 * Deltas with relative base contain an additional
+			 * encoding of the relative offset for the delta
+			 * base from this object's position in the pack.
+			 */
+			off_t ofs = entry->idx.offset - entry->delta->idx.offset;
+			unsigned pos = sizeof(dheader) - 1;
+			dheader[pos] = ofs & 127;
+			while (ofs >>= 7)
+				dheader[--pos] = 128 | (--ofs & 127);
+			if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+				free(buf);
+				return 0;
+			}
+			sha1write(f, header, hdrlen);
+			sha1write(f, dheader + pos, sizeof(dheader) - pos);
+			hdrlen += sizeof(dheader) - pos;
+		} else if (type == OBJ_REF_DELTA) {
+			/*
+			 * Deltas with a base reference contain
+			 * an additional 20 bytes for the base sha1.
+			 */
+			if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+				free(buf);
+				return 0;
+			}
+			sha1write(f, header, hdrlen);
+			sha1write(f, entry->delta->idx.sha1, 20);
+			hdrlen += 20;
+		} else {
+			if (limit && hdrlen + datalen + 20 >= limit) {
+				free(buf);
+				return 0;
+			}
+			sha1write(f, header, hdrlen);
+		}
+		sha1write(f, buf, datalen);
+		free(buf);
+	}
+	else {
+		struct packed_git *p = entry->in_pack;
+		struct pack_window *w_curs = NULL;
+		struct revindex_entry *revidx;
+		off_t offset;
+
+		if (entry->delta)
+			type = (allow_ofs_delta && entry->delta->idx.offset) ?
+				OBJ_OFS_DELTA : OBJ_REF_DELTA;
+		hdrlen = encode_header(type, entry->size, header);
+
+		offset = entry->in_pack_offset;
+		revidx = find_pack_revindex(p, offset);
+		datalen = revidx[1].offset - offset;
+		if (!pack_to_stdout && p->index_version > 1 &&
+		    check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
+			error("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
+			unuse_pack(&w_curs);
+			goto no_reuse;
+		}
+
+		offset += entry->in_pack_header_size;
+		datalen -= entry->in_pack_header_size;
+		if (!pack_to_stdout && p->index_version == 1 &&
+		    check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
+			error("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
+			unuse_pack(&w_curs);
+			goto no_reuse;
+		}
+
+		if (type == OBJ_OFS_DELTA) {
+			off_t ofs = entry->idx.offset - entry->delta->idx.offset;
+			unsigned pos = sizeof(dheader) - 1;
+			dheader[pos] = ofs & 127;
+			while (ofs >>= 7)
+				dheader[--pos] = 128 | (--ofs & 127);
+			if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+				unuse_pack(&w_curs);
+				return 0;
+			}
+			sha1write(f, header, hdrlen);
+			sha1write(f, dheader + pos, sizeof(dheader) - pos);
+			hdrlen += sizeof(dheader) - pos;
+			reused_delta++;
+		} else if (type == OBJ_REF_DELTA) {
+			if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+				unuse_pack(&w_curs);
+				return 0;
+			}
+			sha1write(f, header, hdrlen);
+			sha1write(f, entry->delta->idx.sha1, 20);
+			hdrlen += 20;
+			reused_delta++;
+		} else {
+			if (limit && hdrlen + datalen + 20 >= limit) {
+				unuse_pack(&w_curs);
+				return 0;
+			}
+			sha1write(f, header, hdrlen);
+		}
+		copy_pack_data(f, p, &w_curs, offset, datalen);
+		unuse_pack(&w_curs);
+		reused++;
+	}
+	if (usable_delta)
+		written_delta++;
+	written++;
+	if (!pack_to_stdout)
+		entry->idx.crc32 = crc32_end(f);
+	return hdrlen + datalen;
+}
+
+static int write_one(struct sha1file *f,
+			       struct object_entry *e,
+			       off_t *offset)
+{
+	unsigned long size;
+
+	/* offset is non zero if object is written already. */
+	if (e->idx.offset || e->preferred_base)
+		return -1;
+
+	/* if we are deltified, write out base object first. */
+	if (e->delta && !write_one(f, e->delta, offset))
+		return 0;
+
+	e->idx.offset = *offset;
+	size = write_object(f, e, *offset);
+	if (!size) {
+		e->idx.offset = 0;
+		return 0;
+	}
+	written_list[nr_written++] = &e->idx;
+
+	/* make sure off_t is sufficiently large not to wrap */
+	if (*offset > *offset + size)
+		die("pack too large for current definition of off_t");
+	*offset += size;
+	return 1;
+}
+
+/* forward declaration for write_pack_file */
+static int adjust_perm(const char *path, mode_t mode);
+
+static void write_pack_file(void)
+{
+	uint32_t i = 0, j;
+	struct sha1file *f;
+	off_t offset;
+	struct pack_header hdr;
+	uint32_t nr_remaining = nr_result;
+	time_t last_mtime = 0;
+
+	if (progress > pack_to_stdout)
+		progress_state = start_progress("Writing objects", nr_result);
+	written_list = xmalloc(nr_objects * sizeof(*written_list));
+
+	do {
+		unsigned char sha1[20];
+		char *pack_tmp_name = NULL;
+
+		if (pack_to_stdout) {
+			f = sha1fd_throughput(1, "<stdout>", progress_state);
+		} else {
+			char tmpname[PATH_MAX];
+			int fd;
+			fd = odb_mkstemp(tmpname, sizeof(tmpname),
+					 "pack/tmp_pack_XXXXXX");
+			pack_tmp_name = xstrdup(tmpname);
+			f = sha1fd(fd, pack_tmp_name);
+		}
+
+		hdr.hdr_signature = htonl(PACK_SIGNATURE);
+		hdr.hdr_version = htonl(PACK_VERSION);
+		hdr.hdr_entries = htonl(nr_remaining);
+		sha1write(f, &hdr, sizeof(hdr));
+		offset = sizeof(hdr);
+		nr_written = 0;
+		for (; i < nr_objects; i++) {
+			if (!write_one(f, objects + i, &offset))
+				break;
+			display_progress(progress_state, written);
+		}
+
+		/*
+		 * Did we write the wrong # entries in the header?
+		 * If so, rewrite it like in fast-import
+		 */
+		if (pack_to_stdout) {
+			sha1close(f, sha1, CSUM_CLOSE);
+		} else if (nr_written == nr_remaining) {
+			sha1close(f, sha1, CSUM_FSYNC);
+		} else {
+			int fd = sha1close(f, sha1, 0);
+			fixup_pack_header_footer(fd, sha1, pack_tmp_name,
+						 nr_written, sha1, offset);
+			close(fd);
+		}
+
+		if (!pack_to_stdout) {
+			mode_t mode = umask(0);
+			struct stat st;
+			const char *idx_tmp_name;
+			char tmpname[PATH_MAX];
+
+			umask(mode);
+			mode = 0444 & ~mode;
+
+			idx_tmp_name = write_idx_file(NULL, written_list,
+						      nr_written, sha1);
+
+			snprintf(tmpname, sizeof(tmpname), "%s-%s.pack",
+				 base_name, sha1_to_hex(sha1));
+			free_pack_by_name(tmpname);
+			if (adjust_perm(pack_tmp_name, mode))
+				die_errno("unable to make temporary pack file readable");
+			if (rename(pack_tmp_name, tmpname))
+				die_errno("unable to rename temporary pack file");
+
+			/*
+			 * Packs are runtime accessed in their mtime
+			 * order since newer packs are more likely to contain
+			 * younger objects.  So if we are creating multiple
+			 * packs then we should modify the mtime of later ones
+			 * to preserve this property.
+			 */
+			if (stat(tmpname, &st) < 0) {
+				warning("failed to stat %s: %s",
+					tmpname, strerror(errno));
+			} else if (!last_mtime) {
+				last_mtime = st.st_mtime;
+			} else {
+				struct utimbuf utb;
+				utb.actime = st.st_atime;
+				utb.modtime = --last_mtime;
+				if (utime(tmpname, &utb) < 0)
+					warning("failed utime() on %s: %s",
+						tmpname, strerror(errno));
+			}
+
+			snprintf(tmpname, sizeof(tmpname), "%s-%s.idx",
+				 base_name, sha1_to_hex(sha1));
+			if (adjust_perm(idx_tmp_name, mode))
+				die_errno("unable to make temporary index file readable");
+			if (rename(idx_tmp_name, tmpname))
+				die_errno("unable to rename temporary index file");
+
+			free((void *) idx_tmp_name);
+			free(pack_tmp_name);
+			puts(sha1_to_hex(sha1));
+		}
+
+		/* mark written objects as written to previous pack */
+		for (j = 0; j < nr_written; j++) {
+			written_list[j]->offset = (off_t)-1;
+		}
+		nr_remaining -= nr_written;
+	} while (nr_remaining && i < nr_objects);
+
+	free(written_list);
+	stop_progress(&progress_state);
+	if (written != nr_result)
+		die("wrote %"PRIu32" objects while expecting %"PRIu32,
+			written, nr_result);
+}
+
+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 (!hashcmp(sha1, objects[object_ix[i] - 1].idx.sha1))
+			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)
+{
+	uint32_t 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->idx.sha1);
+		if (0 <= ix)
+			continue;
+		ix = -1 - ix;
+		object_ix[ix] = i + 1;
+	}
+}
+
+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 (isspace(c))
+			continue;
+		hash = (hash >> 2) + (c << 24);
+	}
+	return hash;
+}
+
+static void setup_delta_attr_check(struct git_attr_check *check)
+{
+	static struct git_attr *attr_delta;
+
+	if (!attr_delta)
+		attr_delta = git_attr("delta");
+
+	check[0].attr = attr_delta;
+}
+
+static int no_try_delta(const char *path)
+{
+	struct git_attr_check check[1];
+
+	setup_delta_attr_check(check);
+	if (git_checkattr(path, ARRAY_SIZE(check), check))
+		return 0;
+	if (ATTR_FALSE(check->value))
+		return 1;
+	return 0;
+}
+
+static int add_object_entry(const unsigned char *sha1, enum object_type type,
+			    const char *name, int exclude)
+{
+	struct object_entry *entry;
+	struct packed_git *p, *found_pack = NULL;
+	off_t found_offset = 0;
+	int ix;
+	unsigned hash = name_hash(name);
+
+	ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
+	if (ix >= 0) {
+		if (exclude) {
+			entry = objects + object_ix[ix] - 1;
+			if (!entry->preferred_base)
+				nr_result--;
+			entry->preferred_base = 1;
+		}
+		return 0;
+	}
+
+	if (!exclude && local && has_loose_object_nonlocal(sha1))
+		return 0;
+
+	for (p = packed_git; p; p = p->next) {
+		off_t offset = find_pack_entry_one(sha1, p);
+		if (offset) {
+			if (!found_pack) {
+				found_offset = offset;
+				found_pack = p;
+			}
+			if (exclude)
+				break;
+			if (incremental)
+				return 0;
+			if (local && !p->pack_local)
+				return 0;
+			if (ignore_packed_keep && p->pack_local && p->pack_keep)
+				return 0;
+		}
+	}
+
+	if (nr_objects >= nr_alloc) {
+		nr_alloc = (nr_alloc  + 1024) * 3 / 2;
+		objects = xrealloc(objects, nr_alloc * sizeof(*entry));
+	}
+
+	entry = objects + nr_objects++;
+	memset(entry, 0, sizeof(*entry));
+	hashcpy(entry->idx.sha1, sha1);
+	entry->hash = hash;
+	if (type)
+		entry->type = type;
+	if (exclude)
+		entry->preferred_base = 1;
+	else
+		nr_result++;
+	if (found_pack) {
+		entry->in_pack = found_pack;
+		entry->in_pack_offset = found_offset;
+	}
+
+	if (object_ix_hashsz * 3 <= nr_objects * 4)
+		rehash_objects();
+	else
+		object_ix[-1 - ix] = nr_objects;
+
+	display_progress(progress_state, nr_objects);
+
+	if (name && no_try_delta(name))
+		entry->no_try_delta = 1;
+
+	return 1;
+}
+
+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;
+	enum object_type type;
+	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 && !hashcmp(ent->sha1, sha1)) {
+			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 (type != OBJ_TREE) {
+		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;
+	}
+	hashcpy(nent->sha1, sha1);
+	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;
+	int cmp;
+
+	while (tree_entry(tree,&entry)) {
+		if (S_ISGITLINK(entry.mode))
+			continue;
+		cmp = tree_entry_len(entry.path, entry.sha1) != cmplen ? 1 :
+		      memcmp(name, entry.path, cmplen);
+		if (cmp > 0)
+			continue;
+		if (cmp < 0)
+			return;
+		if (name[cmplen] != '/') {
+			add_object_entry(entry.sha1,
+					 object_type(entry.mode),
+					 fullname, 1);
+			return;
+		}
+		if (S_ISDIR(entry.mode)) {
+			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;
+			init_tree_desc(&sub, tree->tree_data, 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(const char *name)
+{
+	struct pbase_tree *it;
+	int cmplen;
+	unsigned hash = name_hash(name);
+
+	if (!num_preferred_base || check_pbase_path(hash))
+		return;
+
+	cmplen = name_cmp_len(name);
+	for (it = pbase_tree; it; it = it->next) {
+		if (cmplen == 0) {
+			add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
+		}
+		else {
+			struct tree_desc tree;
+			init_tree_desc(&tree, it->pcache.tree_data, 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];
+
+	if (window <= num_preferred_base++)
+		return;
+
+	data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
+	if (!data)
+		return;
+
+	for (it = pbase_tree; it; it = it->next) {
+		if (!hashcmp(it->pcache.sha1, tree_sha1)) {
+			free(data);
+			return;
+		}
+	}
+
+	it = xcalloc(1, sizeof(*it));
+	it->next = pbase_tree;
+	pbase_tree = it;
+
+	hashcpy(it->pcache.sha1, tree_sha1);
+	it->pcache.tree_data = data;
+	it->pcache.tree_size = size;
+}
+
+static void cleanup_preferred_base(void)
+{
+	struct pbase_tree *it;
+	unsigned i;
+
+	it = pbase_tree;
+	pbase_tree = NULL;
+	while (it) {
+		struct pbase_tree *this = it;
+		it = this->next;
+		free(this->pcache.tree_data);
+		free(this);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
+		if (!pbase_tree_cache[i])
+			continue;
+		free(pbase_tree_cache[i]->tree_data);
+		free(pbase_tree_cache[i]);
+		pbase_tree_cache[i] = NULL;
+	}
+
+	free(done_pbase_paths);
+	done_pbase_paths = NULL;
+	done_pbase_paths_num = done_pbase_paths_alloc = 0;
+}
+
+static void check_object(struct object_entry *entry)
+{
+	if (entry->in_pack) {
+		struct packed_git *p = entry->in_pack;
+		struct pack_window *w_curs = NULL;
+		const unsigned char *base_ref = NULL;
+		struct object_entry *base_entry;
+		unsigned long used, used_0;
+		unsigned int avail;
+		off_t ofs;
+		unsigned char *buf, c;
+
+		buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
+
+		/*
+		 * We want in_pack_type even if we do not reuse delta
+		 * since non-delta representations could still be reused.
+		 */
+		used = unpack_object_header_buffer(buf, avail,
+						   &entry->in_pack_type,
+						   &entry->size);
+		if (used == 0)
+			goto give_up;
+
+		/*
+		 * Determine if this is a delta and if so whether we can
+		 * reuse it or not.  Otherwise let's find out as cheaply as
+		 * possible what the actual type and size for this object is.
+		 */
+		switch (entry->in_pack_type) {
+		default:
+			/* Not a delta hence we've already got all we need. */
+			entry->type = entry->in_pack_type;
+			entry->in_pack_header_size = used;
+			if (entry->type < OBJ_COMMIT || entry->type > OBJ_BLOB)
+				goto give_up;
+			unuse_pack(&w_curs);
+			return;
+		case OBJ_REF_DELTA:
+			if (reuse_delta && !entry->preferred_base)
+				base_ref = use_pack(p, &w_curs,
+						entry->in_pack_offset + used, NULL);
+			entry->in_pack_header_size = used + 20;
+			break;
+		case OBJ_OFS_DELTA:
+			buf = use_pack(p, &w_curs,
+				       entry->in_pack_offset + used, NULL);
+			used_0 = 0;
+			c = buf[used_0++];
+			ofs = c & 127;
+			while (c & 128) {
+				ofs += 1;
+				if (!ofs || MSB(ofs, 7)) {
+					error("delta base offset overflow in pack for %s",
+					      sha1_to_hex(entry->idx.sha1));
+					goto give_up;
+				}
+				c = buf[used_0++];
+				ofs = (ofs << 7) + (c & 127);
+			}
+			ofs = entry->in_pack_offset - ofs;
+			if (ofs <= 0 || ofs >= entry->in_pack_offset) {
+				error("delta base offset out of bound for %s",
+				      sha1_to_hex(entry->idx.sha1));
+				goto give_up;
+			}
+			if (reuse_delta && !entry->preferred_base) {
+				struct revindex_entry *revidx;
+				revidx = find_pack_revindex(p, ofs);
+				if (!revidx)
+					goto give_up;
+				base_ref = nth_packed_object_sha1(p, revidx->nr);
+			}
+			entry->in_pack_header_size = used + used_0;
+			break;
+		}
+
+		if (base_ref && (base_entry = locate_object_entry(base_ref))) {
+			/*
+			 * If base_ref was set above that means we wish to
+			 * reuse delta data, and we even found that base
+			 * in the list of objects we want to pack. Goodie!
+			 *
+			 * 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.
+			 */
+			entry->type = entry->in_pack_type;
+			entry->delta = base_entry;
+			entry->delta_size = entry->size;
+			entry->delta_sibling = base_entry->delta_child;
+			base_entry->delta_child = entry;
+			unuse_pack(&w_curs);
+			return;
+		}
+
+		if (entry->type) {
+			/*
+			 * This must be a delta and we already know what the
+			 * final object type is.  Let's extract the actual
+			 * object size from the delta header.
+			 */
+			entry->size = get_size_from_delta(p, &w_curs,
+					entry->in_pack_offset + entry->in_pack_header_size);
+			if (entry->size == 0)
+				goto give_up;
+			unuse_pack(&w_curs);
+			return;
+		}
+
+		/*
+		 * No choice but to fall back to the recursive delta walk
+		 * with sha1_object_info() to find about the object type
+		 * at this point...
+		 */
+		give_up:
+		unuse_pack(&w_curs);
+	}
+
+	entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
+	/*
+	 * The error condition is checked in prepare_pack().  This is
+	 * to permit a missing preferred base object to be ignored
+	 * as a preferred base.  Doing so can result in a larger
+	 * pack file, but the transfer will still take place.
+	 */
+}
+
+static int pack_offset_sort(const void *_a, const void *_b)
+{
+	const struct object_entry *a = *(struct object_entry **)_a;
+	const struct object_entry *b = *(struct object_entry **)_b;
+
+	/* avoid filesystem trashing with loose objects */
+	if (!a->in_pack && !b->in_pack)
+		return hashcmp(a->idx.sha1, b->idx.sha1);
+
+	if (a->in_pack < b->in_pack)
+		return -1;
+	if (a->in_pack > b->in_pack)
+		return 1;
+	return a->in_pack_offset < b->in_pack_offset ? -1 :
+			(a->in_pack_offset > b->in_pack_offset);
+}
+
+static void get_object_details(void)
+{
+	uint32_t i;
+	struct object_entry **sorted_by_offset;
+
+	sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
+	for (i = 0; i < nr_objects; i++)
+		sorted_by_offset[i] = objects + i;
+	qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
+
+	for (i = 0; i < nr_objects; i++)
+		check_object(sorted_by_offset[i]);
+
+	free(sorted_by_offset);
+}
+
+/*
+ * We search for deltas in a list sorted by type, by filename hash, and then
+ * 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.  The deepest deltas are therefore the oldest objects which are
+ * less susceptible to be accessed often.
+ */
+static int type_size_sort(const void *_a, const void *_b)
+{
+	const struct object_entry *a = *(struct object_entry **)_a;
+	const struct object_entry *b = *(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);  /* newest first */
+}
+
+struct unpacked {
+	struct object_entry *entry;
+	void *data;
+	struct delta_index *index;
+	unsigned depth;
+};
+
+static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
+			   unsigned long delta_size)
+{
+	if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
+		return 0;
+
+	if (delta_size < 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;
+}
+
+#ifndef NO_PTHREADS
+
+static pthread_mutex_t read_mutex;
+#define read_lock()		pthread_mutex_lock(&read_mutex)
+#define read_unlock()		pthread_mutex_unlock(&read_mutex)
+
+static pthread_mutex_t cache_mutex;
+#define cache_lock()		pthread_mutex_lock(&cache_mutex)
+#define cache_unlock()		pthread_mutex_unlock(&cache_mutex)
+
+static pthread_mutex_t progress_mutex;
+#define progress_lock()		pthread_mutex_lock(&progress_mutex)
+#define progress_unlock()	pthread_mutex_unlock(&progress_mutex)
+
+#else
+
+#define read_lock()		(void)0
+#define read_unlock()		(void)0
+#define cache_lock()		(void)0
+#define cache_unlock()		(void)0
+#define progress_lock()		(void)0
+#define progress_unlock()	(void)0
+
+#endif
+
+static int try_delta(struct unpacked *trg, struct unpacked *src,
+		     unsigned max_depth, unsigned long *mem_usage)
+{
+	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;
+	unsigned ref_depth;
+	enum object_type type;
+	void *delta_buf;
+
+	/* Don't bother doing diffs between different types */
+	if (trg_entry->type != src_entry->type)
+		return -1;
+
+	/*
+	 * We do not bother to try a delta that we discarded
+	 * on an earlier try, but only when reusing delta data.
+	 */
+	if (reuse_delta && trg_entry->in_pack &&
+	    trg_entry->in_pack == src_entry->in_pack &&
+	    trg_entry->in_pack_type != OBJ_REF_DELTA &&
+	    trg_entry->in_pack_type != OBJ_OFS_DELTA)
+		return 0;
+
+	/* Let's not bust the allowed depth. */
+	if (src->depth >= max_depth)
+		return 0;
+
+	/* Now some size filtering heuristics. */
+	trg_size = trg_entry->size;
+	if (!trg_entry->delta) {
+		max_size = trg_size/2 - 20;
+		ref_depth = 1;
+	} else {
+		max_size = trg_entry->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 = src_entry->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) {
+		read_lock();
+		trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
+		read_unlock();
+		if (!trg->data)
+			die("object %s cannot be read",
+			    sha1_to_hex(trg_entry->idx.sha1));
+		if (sz != trg_size)
+			die("object %s inconsistent object length (%lu vs %lu)",
+			    sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
+		*mem_usage += sz;
+	}
+	if (!src->data) {
+		read_lock();
+		src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
+		read_unlock();
+		if (!src->data)
+			die("object %s cannot be read",
+			    sha1_to_hex(src_entry->idx.sha1));
+		if (sz != src_size)
+			die("object %s inconsistent object length (%lu vs %lu)",
+			    sha1_to_hex(src_entry->idx.sha1), sz, src_size);
+		*mem_usage += sz;
+	}
+	if (!src->index) {
+		src->index = create_delta_index(src->data, src_size);
+		if (!src->index) {
+			static int warned = 0;
+			if (!warned++)
+				warning("suboptimal pack - out of memory");
+			return 0;
+		}
+		*mem_usage += sizeof_delta_index(src->index);
+	}
+
+	delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
+	if (!delta_buf)
+		return 0;
+
+	if (trg_entry->delta) {
+		/* Prefer only shallower same-sized deltas. */
+		if (delta_size == trg_entry->delta_size &&
+		    src->depth + 1 >= trg->depth) {
+			free(delta_buf);
+			return 0;
+		}
+	}
+
+	/*
+	 * Handle memory allocation outside of the cache
+	 * accounting lock.  Compiler will optimize the strangeness
+	 * away when NO_PTHREADS is defined.
+	 */
+	free(trg_entry->delta_data);
+	cache_lock();
+	if (trg_entry->delta_data) {
+		delta_cache_size -= trg_entry->delta_size;
+		trg_entry->delta_data = NULL;
+	}
+	if (delta_cacheable(src_size, trg_size, delta_size)) {
+		delta_cache_size += delta_size;
+		cache_unlock();
+		trg_entry->delta_data = xrealloc(delta_buf, delta_size);
+	} else {
+		cache_unlock();
+		free(delta_buf);
+	}
+
+	trg_entry->delta = src_entry;
+	trg_entry->delta_size = delta_size;
+	trg->depth = src->depth + 1;
+
+	return 1;
+}
+
+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 unsigned long free_unpacked(struct unpacked *n)
+{
+	unsigned long freed_mem = sizeof_delta_index(n->index);
+	free_delta_index(n->index);
+	n->index = NULL;
+	if (n->data) {
+		freed_mem += n->entry->size;
+		free(n->data);
+		n->data = NULL;
+	}
+	n->entry = NULL;
+	n->depth = 0;
+	return freed_mem;
+}
+
+static void find_deltas(struct object_entry **list, unsigned *list_size,
+			int window, int depth, unsigned *processed)
+{
+	uint32_t i, idx = 0, count = 0;
+	struct unpacked *array;
+	unsigned long mem_usage = 0;
+
+	array = xcalloc(window, sizeof(struct unpacked));
+
+	for (;;) {
+		struct object_entry *entry;
+		struct unpacked *n = array + idx;
+		int j, max_depth, best_base = -1;
+
+		progress_lock();
+		if (!*list_size) {
+			progress_unlock();
+			break;
+		}
+		entry = *list++;
+		(*list_size)--;
+		if (!entry->preferred_base) {
+			(*processed)++;
+			display_progress(progress_state, *processed);
+		}
+		progress_unlock();
+
+		mem_usage -= free_unpacked(n);
+		n->entry = entry;
+
+		while (window_memory_limit &&
+		       mem_usage > window_memory_limit &&
+		       count > 1) {
+			uint32_t tail = (idx + window - count) % window;
+			mem_usage -= free_unpacked(array + tail);
+			count--;
+		}
+
+		/* We do not compute delta to *create* objects we are not
+		 * going to pack.
+		 */
+		if (entry->preferred_base)
+			goto next;
+
+		/*
+		 * 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 (entry->delta_child) {
+			max_depth -= check_delta_limit(entry, 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->entry)
+				break;
+			ret = try_delta(n, m, max_depth, &mem_usage);
+			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 (entry->delta_data && !pack_to_stdout) {
+			entry->z_delta_size = do_compress(&entry->delta_data,
+							  entry->delta_size);
+			cache_lock();
+			delta_cache_size -= entry->delta_size;
+			delta_cache_size += entry->z_delta_size;
+			cache_unlock();
+		}
+
+		/* 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 && 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 (entry->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;
+	}
+
+	for (i = 0; i < window; ++i) {
+		free_delta_index(array[i].index);
+		free(array[i].data);
+	}
+	free(array);
+}
+
+#ifndef NO_PTHREADS
+
+/*
+ * The main thread waits on the condition that (at least) one of the workers
+ * has stopped working (which is indicated in the .working member of
+ * struct thread_params).
+ * When a work thread has completed its work, it sets .working to 0 and
+ * signals the main thread and waits on the condition that .data_ready
+ * becomes 1.
+ */
+
+struct thread_params {
+	pthread_t thread;
+	struct object_entry **list;
+	unsigned list_size;
+	unsigned remaining;
+	int window;
+	int depth;
+	int working;
+	int data_ready;
+	pthread_mutex_t mutex;
+	pthread_cond_t cond;
+	unsigned *processed;
+};
+
+static pthread_cond_t progress_cond;
+
+/*
+ * Mutex and conditional variable can't be statically-initialized on Windows.
+ */
+static void init_threaded_search(void)
+{
+	pthread_mutex_init(&read_mutex, NULL);
+	pthread_mutex_init(&cache_mutex, NULL);
+	pthread_mutex_init(&progress_mutex, NULL);
+	pthread_cond_init(&progress_cond, NULL);
+}
+
+static void cleanup_threaded_search(void)
+{
+	pthread_cond_destroy(&progress_cond);
+	pthread_mutex_destroy(&read_mutex);
+	pthread_mutex_destroy(&cache_mutex);
+	pthread_mutex_destroy(&progress_mutex);
+}
+
+static void *threaded_find_deltas(void *arg)
+{
+	struct thread_params *me = arg;
+
+	while (me->remaining) {
+		find_deltas(me->list, &me->remaining,
+			    me->window, me->depth, me->processed);
+
+		progress_lock();
+		me->working = 0;
+		pthread_cond_signal(&progress_cond);
+		progress_unlock();
+
+		/*
+		 * 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.
+		 */
+		pthread_mutex_lock(&me->mutex);
+		while (!me->data_ready)
+			pthread_cond_wait(&me->cond, &me->mutex);
+		me->data_ready = 0;
+		pthread_mutex_unlock(&me->mutex);
+	}
+	/* leave ->working 1 so that this doesn't get more work assigned */
+	return NULL;
+}
+
+static void ll_find_deltas(struct object_entry **list, unsigned list_size,
+			   int window, int depth, unsigned *processed)
+{
+	struct thread_params *p;
+	int i, ret, active_threads = 0;
+
+	init_threaded_search();
+
+	if (!delta_search_threads)	/* --threads=0 means autodetect */
+		delta_search_threads = online_cpus();
+	if (delta_search_threads <= 1) {
+		find_deltas(list, &list_size, window, depth, processed);
+		cleanup_threaded_search();
+		return;
+	}
+	if (progress > pack_to_stdout)
+		fprintf(stderr, "Delta compression using up to %d threads.\n",
+				delta_search_threads);
+	p = xcalloc(delta_search_threads, sizeof(*p));
+
+	/* Partition the work amongst work threads. */
+	for (i = 0; i < delta_search_threads; i++) {
+		unsigned sub_size = list_size / (delta_search_threads - i);
+
+		/* don't use too small segments or no deltas will be found */
+		if (sub_size < 2*window && i+1 < delta_search_threads)
+			sub_size = 0;
+
+		p[i].window = window;
+		p[i].depth = depth;
+		p[i].processed = processed;
+		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 < delta_search_threads; i++) {
+		if (!p[i].list_size)
+			continue;
+		pthread_mutex_init(&p[i].mutex, NULL);
+		pthread_cond_init(&p[i].cond, NULL);
+		ret = pthread_create(&p[i].thread, NULL,
+				     threaded_find_deltas, &p[i]);
+		if (ret)
+			die("unable to create thread: %s", strerror(ret));
+		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;
+
+		progress_lock();
+		for (;;) {
+			for (i = 0; !target && i < delta_search_threads; i++)
+				if (!p[i].working)
+					target = &p[i];
+			if (target)
+				break;
+			pthread_cond_wait(&progress_cond, &progress_mutex);
+		}
+
+		for (i = 0; i < delta_search_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;
+		progress_unlock();
+
+		pthread_mutex_lock(&target->mutex);
+		target->data_ready = 1;
+		pthread_cond_signal(&target->cond);
+		pthread_mutex_unlock(&target->mutex);
+
+		if (!sub_size) {
+			pthread_join(target->thread, NULL);
+			pthread_cond_destroy(&target->cond);
+			pthread_mutex_destroy(&target->mutex);
+			active_threads--;
+		}
+	}
+	cleanup_threaded_search();
+	free(p);
+}
+
+#else
+#define ll_find_deltas(l, s, w, d, p)	find_deltas(l, &s, w, d, p)
+#endif
+
+static int add_ref_tag(const char *path, const unsigned char *sha1, int flag, void *cb_data)
+{
+	unsigned char peeled[20];
+
+	if (!prefixcmp(path, "refs/tags/") && /* is a tag? */
+	    !peel_ref(path, peeled)        && /* peelable? */
+	    !is_null_sha1(peeled)          && /* annotated tag? */
+	    locate_object_entry(peeled))      /* object packed? */
+		add_object_entry(sha1, OBJ_TAG, NULL, 0);
+	return 0;
+}
+
+static void prepare_pack(int window, int depth)
+{
+	struct object_entry **delta_list;
+	uint32_t i, nr_deltas;
+	unsigned n;
+
+	get_object_details();
+
+	/*
+	 * If we're locally repacking then we need to be doubly careful
+	 * from now on in order to make sure no stealth corruption gets
+	 * propagated to the new pack.  Clients receiving streamed packs
+	 * should validate everything they get anyway so no need to incur
+	 * the additional cost here in that case.
+	 */
+	if (!pack_to_stdout)
+		do_check_packed_object_crc = 1;
+
+	if (!nr_objects || !window || !depth)
+		return;
+
+	delta_list = xmalloc(nr_objects * sizeof(*delta_list));
+	nr_deltas = n = 0;
+
+	for (i = 0; i < nr_objects; i++) {
+		struct object_entry *entry = objects + i;
+
+		if (entry->delta)
+			/* This happens if we decided to reuse existing
+			 * delta from a pack.  "reuse_delta &&" is implied.
+			 */
+			continue;
+
+		if (entry->size < 50)
+			continue;
+
+		if (entry->no_try_delta)
+			continue;
+
+		if (!entry->preferred_base) {
+			nr_deltas++;
+			if (entry->type < 0)
+				die("unable to get type of object %s",
+				    sha1_to_hex(entry->idx.sha1));
+		} else {
+			if (entry->type < 0) {
+				/*
+				 * This object is not found, but we
+				 * don't have to include it anyway.
+				 */
+				continue;
+			}
+		}
+
+		delta_list[n++] = entry;
+	}
+
+	if (nr_deltas && n > 1) {
+		unsigned nr_done = 0;
+		if (progress)
+			progress_state = start_progress("Compressing objects",
+							nr_deltas);
+		qsort(delta_list, n, sizeof(*delta_list), type_size_sort);
+		ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
+		stop_progress(&progress_state);
+		if (nr_done != nr_deltas)
+			die("inconsistency with delta count");
+	}
+	free(delta_list);
+}
+
+static int git_pack_config(const char *k, const char *v, void *cb)
+{
+	if (!strcmp(k, "pack.window")) {
+		window = git_config_int(k, v);
+		return 0;
+	}
+	if (!strcmp(k, "pack.windowmemory")) {
+		window_memory_limit = git_config_ulong(k, v);
+		return 0;
+	}
+	if (!strcmp(k, "pack.depth")) {
+		depth = git_config_int(k, v);
+		return 0;
+	}
+	if (!strcmp(k, "pack.compression")) {
+		int level = git_config_int(k, v);
+		if (level == -1)
+			level = Z_DEFAULT_COMPRESSION;
+		else if (level < 0 || level > Z_BEST_COMPRESSION)
+			die("bad pack compression level %d", level);
+		pack_compression_level = level;
+		pack_compression_seen = 1;
+		return 0;
+	}
+	if (!strcmp(k, "pack.deltacachesize")) {
+		max_delta_cache_size = git_config_int(k, v);
+		return 0;
+	}
+	if (!strcmp(k, "pack.deltacachelimit")) {
+		cache_max_small_delta_size = git_config_int(k, v);
+		return 0;
+	}
+	if (!strcmp(k, "pack.threads")) {
+		delta_search_threads = git_config_int(k, v);
+		if (delta_search_threads < 0)
+			die("invalid number of threads specified (%d)",
+			    delta_search_threads);
+#ifdef NO_PTHREADS
+		if (delta_search_threads != 1)
+			warning("no threads support, ignoring %s", k);
+#endif
+		return 0;
+	}
+	if (!strcmp(k, "pack.indexversion")) {
+		pack_idx_default_version = git_config_int(k, v);
+		if (pack_idx_default_version > 2)
+			die("bad pack.indexversion=%"PRIu32,
+				pack_idx_default_version);
+		return 0;
+	}
+	if (!strcmp(k, "pack.packsizelimit")) {
+		pack_size_limit_cfg = git_config_ulong(k, v);
+		return 0;
+	}
+	return git_default_config(k, v, cb);
+}
+
+static void read_object_list_from_stdin(void)
+{
+	char line[40 + 1 + PATH_MAX + 2];
+	unsigned char sha1[20];
+
+	for (;;) {
+		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_errno("fgets");
+			clearerr(stdin);
+			continue;
+		}
+		if (line[0] == '-') {
+			if (get_sha1_hex(line+1, sha1))
+				die("expected edge sha1, got garbage:\n %s",
+				    line);
+			add_preferred_base(sha1);
+			continue;
+		}
+		if (get_sha1_hex(line, sha1))
+			die("expected sha1, got garbage:\n %s", line);
+
+		add_preferred_base_object(line+41);
+		add_object_entry(sha1, 0, line+41, 0);
+	}
+}
+
+#define OBJECT_ADDED (1u<<20)
+
+static void show_commit(struct commit *commit, void *data)
+{
+	add_object_entry(commit->object.sha1, OBJ_COMMIT, NULL, 0);
+	commit->object.flags |= OBJECT_ADDED;
+}
+
+static void show_object(struct object *obj, const struct name_path *path, const char *last)
+{
+	char *name = path_name(path, last);
+
+	add_preferred_base_object(name);
+	add_object_entry(obj->sha1, obj->type, name, 0);
+	obj->flags |= OBJECT_ADDED;
+
+	/*
+	 * We will have generated the hash from the name,
+	 * but not saved a pointer to it - we can free it
+	 */
+	free((char *)name);
+}
+
+static void show_edge(struct commit *commit)
+{
+	add_preferred_base(commit->object.sha1);
+}
+
+struct in_pack_object {
+	off_t offset;
+	struct object *object;
+};
+
+struct in_pack {
+	int alloc;
+	int nr;
+	struct in_pack_object *array;
+};
+
+static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
+{
+	in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->sha1, p);
+	in_pack->array[in_pack->nr].object = object;
+	in_pack->nr++;
+}
+
+/*
+ * Compare the objects in the offset order, in order to emulate the
+ * "git rev-list --objects" output that produced the pack originally.
+ */
+static int ofscmp(const void *a_, const void *b_)
+{
+	struct in_pack_object *a = (struct in_pack_object *)a_;
+	struct in_pack_object *b = (struct in_pack_object *)b_;
+
+	if (a->offset < b->offset)
+		return -1;
+	else if (a->offset > b->offset)
+		return 1;
+	else
+		return hashcmp(a->object->sha1, b->object->sha1);
+}
+
+static void add_objects_in_unpacked_packs(struct rev_info *revs)
+{
+	struct packed_git *p;
+	struct in_pack in_pack;
+	uint32_t i;
+
+	memset(&in_pack, 0, sizeof(in_pack));
+
+	for (p = packed_git; p; p = p->next) {
+		const unsigned char *sha1;
+		struct object *o;
+
+		if (!p->pack_local || p->pack_keep)
+			continue;
+		if (open_pack_index(p))
+			die("cannot open pack index");
+
+		ALLOC_GROW(in_pack.array,
+			   in_pack.nr + p->num_objects,
+			   in_pack.alloc);
+
+		for (i = 0; i < p->num_objects; i++) {
+			sha1 = nth_packed_object_sha1(p, i);
+			o = lookup_unknown_object(sha1);
+			if (!(o->flags & OBJECT_ADDED))
+				mark_in_pack_object(o, p, &in_pack);
+			o->flags |= OBJECT_ADDED;
+		}
+	}
+
+	if (in_pack.nr) {
+		qsort(in_pack.array, in_pack.nr, sizeof(in_pack.array[0]),
+		      ofscmp);
+		for (i = 0; i < in_pack.nr; i++) {
+			struct object *o = in_pack.array[i].object;
+			add_object_entry(o->sha1, o->type, "", 0);
+		}
+	}
+	free(in_pack.array);
+}
+
+static int has_sha1_pack_kept_or_nonlocal(const unsigned char *sha1)
+{
+	static struct packed_git *last_found = (void *)1;
+	struct packed_git *p;
+
+	p = (last_found != (void *)1) ? last_found : packed_git;
+
+	while (p) {
+		if ((!p->pack_local || p->pack_keep) &&
+			find_pack_entry_one(sha1, p)) {
+			last_found = p;
+			return 1;
+		}
+		if (p == last_found)
+			p = packed_git;
+		else
+			p = p->next;
+		if (p == last_found)
+			p = p->next;
+	}
+	return 0;
+}
+
+static void loosen_unused_packed_objects(struct rev_info *revs)
+{
+	struct packed_git *p;
+	uint32_t i;
+	const unsigned char *sha1;
+
+	for (p = packed_git; p; p = p->next) {
+		if (!p->pack_local || p->pack_keep)
+			continue;
+
+		if (open_pack_index(p))
+			die("cannot open pack index");
+
+		for (i = 0; i < p->num_objects; i++) {
+			sha1 = nth_packed_object_sha1(p, i);
+			if (!locate_object_entry(sha1) &&
+				!has_sha1_pack_kept_or_nonlocal(sha1))
+				if (force_object_loose(sha1, p->mtime))
+					die("unable to force loose object");
+		}
+	}
+}
+
+static void get_object_list(int ac, const char **av)
+{
+	struct rev_info revs;
+	char line[1000];
+	int flags = 0;
+
+	init_revisions(&revs, NULL);
+	save_commit_buffer = 0;
+	setup_revisions(ac, av, &revs, NULL);
+
+	while (fgets(line, sizeof(line), stdin) != NULL) {
+		int len = strlen(line);
+		if (len && line[len - 1] == '\n')
+			line[--len] = 0;
+		if (!len)
+			break;
+		if (*line == '-') {
+			if (!strcmp(line, "--not")) {
+				flags ^= UNINTERESTING;
+				continue;
+			}
+			die("not a rev '%s'", line);
+		}
+		if (handle_revision_arg(line, &revs, flags, 1))
+			die("bad revision '%s'", line);
+	}
+
+	if (prepare_revision_walk(&revs))
+		die("revision walk setup failed");
+	mark_edges_uninteresting(revs.commits, &revs, show_edge);
+	traverse_commit_list(&revs, show_commit, show_object, NULL);
+
+	if (keep_unreachable)
+		add_objects_in_unpacked_packs(&revs);
+	if (unpack_unreachable)
+		loosen_unused_packed_objects(&revs);
+}
+
+static int adjust_perm(const char *path, mode_t mode)
+{
+	if (chmod(path, mode))
+		return -1;
+	return adjust_shared_perm(path);
+}
+
+int cmd_pack_objects(int argc, const char **argv, const char *prefix)
+{
+	int use_internal_rev_list = 0;
+	int thin = 0;
+	int all_progress_implied = 0;
+	uint32_t i;
+	const char **rp_av;
+	int rp_ac_alloc = 64;
+	int rp_ac;
+
+	read_replace_refs = 0;
+
+	rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
+
+	rp_av[0] = "pack-objects";
+	rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
+	rp_ac = 2;
+
+	git_config(git_pack_config, NULL);
+	if (!pack_compression_seen && core_compression_seen)
+		pack_compression_level = core_compression_level;
+
+	progress = isatty(2);
+	for (i = 1; i < argc; i++) {
+		const char *arg = argv[i];
+
+		if (*arg != '-')
+			break;
+
+		if (!strcmp("--non-empty", arg)) {
+			non_empty = 1;
+			continue;
+		}
+		if (!strcmp("--local", arg)) {
+			local = 1;
+			continue;
+		}
+		if (!strcmp("--incremental", arg)) {
+			incremental = 1;
+			continue;
+		}
+		if (!strcmp("--honor-pack-keep", arg)) {
+			ignore_packed_keep = 1;
+			continue;
+		}
+		if (!prefixcmp(arg, "--compression=")) {
+			char *end;
+			int level = strtoul(arg+14, &end, 0);
+			if (!arg[14] || *end)
+				usage(pack_usage);
+			if (level == -1)
+				level = Z_DEFAULT_COMPRESSION;
+			else if (level < 0 || level > Z_BEST_COMPRESSION)
+				die("bad pack compression level %d", level);
+			pack_compression_level = level;
+			continue;
+		}
+		if (!prefixcmp(arg, "--max-pack-size=")) {
+			pack_size_limit_cfg = 0;
+			if (!git_parse_ulong(arg+16, &pack_size_limit))
+				usage(pack_usage);
+			continue;
+		}
+		if (!prefixcmp(arg, "--window=")) {
+			char *end;
+			window = strtoul(arg+9, &end, 0);
+			if (!arg[9] || *end)
+				usage(pack_usage);
+			continue;
+		}
+		if (!prefixcmp(arg, "--window-memory=")) {
+			if (!git_parse_ulong(arg+16, &window_memory_limit))
+				usage(pack_usage);
+			continue;
+		}
+		if (!prefixcmp(arg, "--threads=")) {
+			char *end;
+			delta_search_threads = strtoul(arg+10, &end, 0);
+			if (!arg[10] || *end || delta_search_threads < 0)
+				usage(pack_usage);
+#ifdef NO_PTHREADS
+			if (delta_search_threads != 1)
+				warning("no threads support, "
+					"ignoring %s", arg);
+#endif
+			continue;
+		}
+		if (!prefixcmp(arg, "--depth=")) {
+			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("--all-progress", arg)) {
+			progress = 2;
+			continue;
+		}
+		if (!strcmp("--all-progress-implied", arg)) {
+			all_progress_implied = 1;
+			continue;
+		}
+		if (!strcmp("-q", arg)) {
+			progress = 0;
+			continue;
+		}
+		if (!strcmp("--no-reuse-delta", arg)) {
+			reuse_delta = 0;
+			continue;
+		}
+		if (!strcmp("--no-reuse-object", arg)) {
+			reuse_object = reuse_delta = 0;
+			continue;
+		}
+		if (!strcmp("--delta-base-offset", arg)) {
+			allow_ofs_delta = 1;
+			continue;
+		}
+		if (!strcmp("--stdout", arg)) {
+			pack_to_stdout = 1;
+			continue;
+		}
+		if (!strcmp("--revs", arg)) {
+			use_internal_rev_list = 1;
+			continue;
+		}
+		if (!strcmp("--keep-unreachable", arg)) {
+			keep_unreachable = 1;
+			continue;
+		}
+		if (!strcmp("--unpack-unreachable", arg)) {
+			unpack_unreachable = 1;
+			continue;
+		}
+		if (!strcmp("--include-tag", arg)) {
+			include_tag = 1;
+			continue;
+		}
+		if (!strcmp("--unpacked", arg) ||
+		    !strcmp("--reflog", arg) ||
+		    !strcmp("--all", arg)) {
+			use_internal_rev_list = 1;
+			if (rp_ac >= rp_ac_alloc - 1) {
+				rp_ac_alloc = alloc_nr(rp_ac_alloc);
+				rp_av = xrealloc(rp_av,
+						 rp_ac_alloc * sizeof(*rp_av));
+			}
+			rp_av[rp_ac++] = arg;
+			continue;
+		}
+		if (!strcmp("--thin", arg)) {
+			use_internal_rev_list = 1;
+			thin = 1;
+			rp_av[1] = "--objects-edge";
+			continue;
+		}
+		if (!prefixcmp(arg, "--index-version=")) {
+			char *c;
+			pack_idx_default_version = strtoul(arg + 16, &c, 10);
+			if (pack_idx_default_version > 2)
+				die("bad %s", arg);
+			if (*c == ',')
+				pack_idx_off32_limit = strtoul(c+1, &c, 0);
+			if (*c || pack_idx_off32_limit & 0x80000000)
+				die("bad %s", arg);
+			continue;
+		}
+		if (!strcmp(arg, "--keep-true-parents")) {
+			grafts_replace_parents = 0;
+			continue;
+		}
+		usage(pack_usage);
+	}
+
+	/* Traditionally "pack-objects [options] base extra" failed;
+	 * we would however want to take refs parameter that would
+	 * have been given to upstream rev-list ourselves, which means
+	 * we somehow want to say what the base name is.  So the
+	 * syntax would be:
+	 *
+	 * pack-objects [options] base <refs...>
+	 *
+	 * in other words, we would treat the first non-option as the
+	 * base_name and send everything else to the internal revision
+	 * walker.
+	 */
+
+	if (!pack_to_stdout)
+		base_name = argv[i++];
+
+	if (pack_to_stdout != !base_name)
+		usage(pack_usage);
+
+	if (!pack_to_stdout && !pack_size_limit)
+		pack_size_limit = pack_size_limit_cfg;
+	if (pack_to_stdout && pack_size_limit)
+		die("--max-pack-size cannot be used to build a pack for transfer.");
+	if (pack_size_limit && pack_size_limit < 1024*1024) {
+		warning("minimum pack size limit is 1 MiB");
+		pack_size_limit = 1024*1024;
+	}
+
+	if (!pack_to_stdout && thin)
+		die("--thin cannot be used to build an indexable pack.");
+
+	if (keep_unreachable && unpack_unreachable)
+		die("--keep-unreachable and --unpack-unreachable are incompatible.");
+
+	if (progress && all_progress_implied)
+		progress = 2;
+
+	prepare_packed_git();
+
+	if (progress)
+		progress_state = start_progress("Counting objects", 0);
+	if (!use_internal_rev_list)
+		read_object_list_from_stdin();
+	else {
+		rp_av[rp_ac] = NULL;
+		get_object_list(rp_ac, rp_av);
+	}
+	cleanup_preferred_base();
+	if (include_tag && nr_result)
+		for_each_ref(add_ref_tag, NULL);
+	stop_progress(&progress_state);
+
+	if (non_empty && !nr_result)
+		return 0;
+	if (nr_result)
+		prepare_pack(window, depth);
+	write_pack_file();
+	if (progress)
+		fprintf(stderr, "Total %"PRIu32" (delta %"PRIu32"),"
+			" reused %"PRIu32" (delta %"PRIu32")\n",
+			written, written_delta, reused, reused_delta);
+	return 0;
+}