Merge branch 'np/index-pack-memsave'

* np/index-pack-memsave:
  index-pack: smarter memory usage when appending objects
  index-pack: rationalize unpack_entry_data()
  index-pack: smarter memory usage when resolving deltas

diff --cc builtin/index-pack.c
index 03d0cd2f47016b59994a75c11403061fcad8a165,0000000000000000000000000000000000000000..a89ae831dd6251d7332e06470273d30fd9cb31eb
mode 100644,000000..100644
--- 1/builtin/index-pack.c
--- /dev/null
+++ b/builtin/index-pack.c
@@@ -1,1045 -1,0 +1,1046 @@@
-       stream.next_in = fill(1);
-       stream.avail_in = input_len;
-       git_inflate_init(&stream);
 +#include "cache.h"
 +#include "delta.h"
 +#include "pack.h"
 +#include "csum-file.h"
 +#include "blob.h"
 +#include "commit.h"
 +#include "tag.h"
 +#include "tree.h"
 +#include "progress.h"
 +#include "fsck.h"
 +#include "exec_cmd.h"
 +
 +static const char index_pack_usage[] =
 +"git index-pack [-v] [-o <index-file>] [{ --keep | --keep=<msg> }] [--strict] { <pack-file> | --stdin [--fix-thin] [<pack-file>] }";
 +
 +struct object_entry
 +{
 +      struct pack_idx_entry idx;
 +      unsigned long size;
 +      unsigned int hdr_size;
 +      enum object_type type;
 +      enum object_type real_type;
 +};
 +
 +union delta_base {
 +      unsigned char sha1[20];
 +      off_t offset;
 +};
 +
 +struct base_data {
 +      struct base_data *base;
 +      struct base_data *child;
 +      struct object_entry *obj;
 +      void *data;
 +      unsigned long size;
 +};
 +
 +/*
 + * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
 + * to memcmp() only the first 20 bytes.
 + */
 +#define UNION_BASE_SZ 20
 +
 +#define FLAG_LINK (1u<<20)
 +#define FLAG_CHECKED (1u<<21)
 +
 +struct delta_entry
 +{
 +      union delta_base base;
 +      int obj_no;
 +};
 +
 +static struct object_entry *objects;
 +static struct delta_entry *deltas;
 +static struct base_data *base_cache;
 +static size_t base_cache_used;
 +static int nr_objects;
 +static int nr_deltas;
 +static int nr_resolved_deltas;
 +
 +static int from_stdin;
 +static int strict;
 +static int verbose;
 +
 +static struct progress *progress;
 +
 +/* We always read in 4kB chunks. */
 +static unsigned char input_buffer[4096];
 +static unsigned int input_offset, input_len;
 +static off_t consumed_bytes;
 +static git_SHA_CTX input_ctx;
 +static uint32_t input_crc32;
 +static int input_fd, output_fd, pack_fd;
 +
 +static int mark_link(struct object *obj, int type, void *data)
 +{
 +      if (!obj)
 +              return -1;
 +
 +      if (type != OBJ_ANY && obj->type != type)
 +              die("object type mismatch at %s", sha1_to_hex(obj->sha1));
 +
 +      obj->flags |= FLAG_LINK;
 +      return 0;
 +}
 +
 +/* The content of each linked object must have been checked
 +   or it must be already present in the object database */
 +static void check_object(struct object *obj)
 +{
 +      if (!obj)
 +              return;
 +
 +      if (!(obj->flags & FLAG_LINK))
 +              return;
 +
 +      if (!(obj->flags & FLAG_CHECKED)) {
 +              unsigned long size;
 +              int type = sha1_object_info(obj->sha1, &size);
 +              if (type != obj->type || type <= 0)
 +                      die("object of unexpected type");
 +              obj->flags |= FLAG_CHECKED;
 +              return;
 +      }
 +}
 +
 +static void check_objects(void)
 +{
 +      unsigned i, max;
 +
 +      max = get_max_object_index();
 +      for (i = 0; i < max; i++)
 +              check_object(get_indexed_object(i));
 +}
 +
 +
 +/* Discard current buffer used content. */
 +static void flush(void)
 +{
 +      if (input_offset) {
 +              if (output_fd >= 0)
 +                      write_or_die(output_fd, input_buffer, input_offset);
 +              git_SHA1_Update(&input_ctx, input_buffer, input_offset);
 +              memmove(input_buffer, input_buffer + input_offset, input_len);
 +              input_offset = 0;
 +      }
 +}
 +
 +/*
 + * Make sure at least "min" bytes are available in the buffer, and
 + * return the pointer to the buffer.
 + */
 +static void *fill(int min)
 +{
 +      if (min <= input_len)
 +              return input_buffer + input_offset;
 +      if (min > sizeof(input_buffer))
 +              die("cannot fill %d bytes", min);
 +      flush();
 +      do {
 +              ssize_t ret = xread(input_fd, input_buffer + input_len,
 +                              sizeof(input_buffer) - input_len);
 +              if (ret <= 0) {
 +                      if (!ret)
 +                              die("early EOF");
 +                      die_errno("read error on input");
 +              }
 +              input_len += ret;
 +              if (from_stdin)
 +                      display_throughput(progress, consumed_bytes + input_len);
 +      } while (input_len < min);
 +      return input_buffer;
 +}
 +
 +static void use(int bytes)
 +{
 +      if (bytes > input_len)
 +              die("used more bytes than were available");
 +      input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 +      input_len -= bytes;
 +      input_offset += bytes;
 +
 +      /* make sure off_t is sufficiently large not to wrap */
 +      if (consumed_bytes > consumed_bytes + bytes)
 +              die("pack too large for current definition of off_t");
 +      consumed_bytes += bytes;
 +}
 +
 +static const char *open_pack_file(const char *pack_name)
 +{
 +      if (from_stdin) {
 +              input_fd = 0;
 +              if (!pack_name) {
 +                      static char tmpfile[PATH_MAX];
 +                      output_fd = odb_mkstemp(tmpfile, sizeof(tmpfile),
 +                                              "pack/tmp_pack_XXXXXX");
 +                      pack_name = xstrdup(tmpfile);
 +              } else
 +                      output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 +              if (output_fd < 0)
 +                      die_errno("unable to create '%s'", pack_name);
 +              pack_fd = output_fd;
 +      } else {
 +              input_fd = open(pack_name, O_RDONLY);
 +              if (input_fd < 0)
 +                      die_errno("cannot open packfile '%s'", pack_name);
 +              output_fd = -1;
 +              pack_fd = input_fd;
 +      }
 +      git_SHA1_Init(&input_ctx);
 +      return pack_name;
 +}
 +
 +static void parse_pack_header(void)
 +{
 +      struct pack_header *hdr = fill(sizeof(struct pack_header));
 +
 +      /* Header consistency check */
 +      if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 +              die("pack signature mismatch");
 +      if (!pack_version_ok(hdr->hdr_version))
 +              die("pack version %"PRIu32" unsupported",
 +                      ntohl(hdr->hdr_version));
 +
 +      nr_objects = ntohl(hdr->hdr_entries);
 +      use(sizeof(struct pack_header));
 +}
 +
 +static NORETURN void bad_object(unsigned long offset, const char *format,
 +                     ...) __attribute__((format (printf, 2, 3)));
 +
 +static void bad_object(unsigned long offset, const char *format, ...)
 +{
 +      va_list params;
 +      char buf[1024];
 +
 +      va_start(params, format);
 +      vsnprintf(buf, sizeof(buf), format, params);
 +      va_end(params);
 +      die("pack has bad object at offset %lu: %s", offset, buf);
 +}
 +
 +static void free_base_data(struct base_data *c)
 +{
 +      if (c->data) {
 +              free(c->data);
 +              c->data = NULL;
 +              base_cache_used -= c->size;
 +      }
 +}
 +
 +static void prune_base_data(struct base_data *retain)
 +{
 +      struct base_data *b;
 +      for (b = base_cache;
 +           base_cache_used > delta_base_cache_limit && b;
 +           b = b->child) {
 +              if (b->data && b != retain)
 +                      free_base_data(b);
 +      }
 +}
 +
 +static void link_base_data(struct base_data *base, struct base_data *c)
 +{
 +      if (base)
 +              base->child = c;
 +      else
 +              base_cache = c;
 +
 +      c->base = base;
 +      c->child = NULL;
 +      if (c->data)
 +              base_cache_used += c->size;
 +      prune_base_data(c);
 +}
 +
 +static void unlink_base_data(struct base_data *c)
 +{
 +      struct base_data *base = c->base;
 +      if (base)
 +              base->child = NULL;
 +      else
 +              base_cache = NULL;
 +      free_base_data(c);
 +}
 +
 +static void *unpack_entry_data(unsigned long offset, unsigned long size)
 +{
++      int status;
 +      z_stream stream;
 +      void *buf = xmalloc(size);
 +
 +      memset(&stream, 0, sizeof(stream));
++      git_inflate_init(&stream);
 +      stream.next_out = buf;
 +      stream.avail_out = size;
-       for (;;) {
-               int ret = git_inflate(&stream, 0);
-               use(input_len - stream.avail_in);
-               if (stream.total_out == size && ret == Z_STREAM_END)
-                       break;
-               if (ret != Z_OK)
-                       bad_object(offset, "inflate returned %d", ret);
 +
-       }
++      do {
 +              stream.next_in = fill(1);
 +              stream.avail_in = input_len;
-       unsigned long rdy = 0;
-       unsigned char *src, *data;
++              status = git_inflate(&stream, 0);
++              use(input_len - stream.avail_in);
++      } while (status == Z_OK);
++      if (stream.total_out != size || status != Z_STREAM_END)
++              bad_object(offset, "inflate returned %d", status);
 +      git_inflate_end(&stream);
 +      return buf;
 +}
 +
 +static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
 +{
 +      unsigned char *p;
 +      unsigned long size, c;
 +      off_t base_offset;
 +      unsigned shift;
 +      void *data;
 +
 +      obj->idx.offset = consumed_bytes;
 +      input_crc32 = crc32(0, Z_NULL, 0);
 +
 +      p = fill(1);
 +      c = *p;
 +      use(1);
 +      obj->type = (c >> 4) & 7;
 +      size = (c & 15);
 +      shift = 4;
 +      while (c & 0x80) {
 +              p = fill(1);
 +              c = *p;
 +              use(1);
 +              size += (c & 0x7f) << shift;
 +              shift += 7;
 +      }
 +      obj->size = size;
 +
 +      switch (obj->type) {
 +      case OBJ_REF_DELTA:
 +              hashcpy(delta_base->sha1, fill(20));
 +              use(20);
 +              break;
 +      case OBJ_OFS_DELTA:
 +              memset(delta_base, 0, sizeof(*delta_base));
 +              p = fill(1);
 +              c = *p;
 +              use(1);
 +              base_offset = c & 127;
 +              while (c & 128) {
 +                      base_offset += 1;
 +                      if (!base_offset || MSB(base_offset, 7))
 +                              bad_object(obj->idx.offset, "offset value overflow for delta base object");
 +                      p = fill(1);
 +                      c = *p;
 +                      use(1);
 +                      base_offset = (base_offset << 7) + (c & 127);
 +              }
 +              delta_base->offset = obj->idx.offset - base_offset;
 +              if (delta_base->offset <= 0 || delta_base->offset >= obj->idx.offset)
 +                      bad_object(obj->idx.offset, "delta base offset is out of bound");
 +              break;
 +      case OBJ_COMMIT:
 +      case OBJ_TREE:
 +      case OBJ_BLOB:
 +      case OBJ_TAG:
 +              break;
 +      default:
 +              bad_object(obj->idx.offset, "unknown object type %d", obj->type);
 +      }
 +      obj->hdr_size = consumed_bytes - obj->idx.offset;
 +
 +      data = unpack_entry_data(obj->idx.offset, obj->size);
 +      obj->idx.crc32 = input_crc32;
 +      return data;
 +}
 +
 +static void *get_data_from_pack(struct object_entry *obj)
 +{
 +      off_t from = obj[0].idx.offset + obj[0].hdr_size;
 +      unsigned long len = obj[1].idx.offset - from;
-       int st;
++      unsigned char *data, *inbuf;
 +      z_stream stream;
-       src = xmalloc(len);
-       data = src;
-       do {
-               ssize_t n = pread(pack_fd, data + rdy, len - rdy, from + rdy);
-               if (n < 0)
-                       die_errno("cannot pread pack file");
-               if (!n)
-                       die("premature end of pack file, %lu bytes missing",
-                           len - rdy);
-               rdy += n;
-       } while (rdy < len);
++      int status;
 +
-       stream.next_in = src;
-       stream.avail_in = len;
-       git_inflate_init(&stream);
-       while ((st = git_inflate(&stream, Z_FINISH)) == Z_OK);
-       git_inflate_end(&stream);
-       if (st != Z_STREAM_END || stream.total_out != obj->size)
 +      data = xmalloc(obj->size);
++      inbuf = xmalloc((len < 64*1024) ? len : 64*1024);
++
 +      memset(&stream, 0, sizeof(stream));
++      git_inflate_init(&stream);
 +      stream.next_out = data;
 +      stream.avail_out = obj->size;
-       free(src);
++
++      do {
++              ssize_t n = (len < 64*1024) ? len : 64*1024;
++              n = pread(pack_fd, inbuf, n, from);
++              if (n < 0)
++                      die_errno("cannot pread pack file");
++              if (!n)
++                      die("premature end of pack file, %lu bytes missing", len);
++              from += n;
++              len -= n;
++              stream.next_in = inbuf;
++              stream.avail_in = n;
++              status = git_inflate(&stream, 0);
++      } while (len && status == Z_OK && !stream.avail_in);
++
++      /* This has been inflated OK when first encountered, so... */
++      if (status != Z_STREAM_END || stream.total_out != obj->size)
 +              die("serious inflate inconsistency");
-       unsigned long maxsize;
-       void *out;
++
++      git_inflate_end(&stream);
++      free(inbuf);
 +      return data;
 +}
 +
 +static int find_delta(const union delta_base *base)
 +{
 +      int first = 0, last = nr_deltas;
 +
 +        while (first < last) {
 +                int next = (first + last) / 2;
 +                struct delta_entry *delta = &deltas[next];
 +                int cmp;
 +
 +                cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
 +                if (!cmp)
 +                        return next;
 +                if (cmp < 0) {
 +                        last = next;
 +                        continue;
 +                }
 +                first = next+1;
 +        }
 +        return -first-1;
 +}
 +
 +static void find_delta_children(const union delta_base *base,
 +                              int *first_index, int *last_index)
 +{
 +      int first = find_delta(base);
 +      int last = first;
 +      int end = nr_deltas - 1;
 +
 +      if (first < 0) {
 +              *first_index = 0;
 +              *last_index = -1;
 +              return;
 +      }
 +      while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
 +              --first;
 +      while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
 +              ++last;
 +      *first_index = first;
 +      *last_index = last;
 +}
 +
 +static void sha1_object(const void *data, unsigned long size,
 +                      enum object_type type, unsigned char *sha1)
 +{
 +      hash_sha1_file(data, size, typename(type), sha1);
 +      if (has_sha1_file(sha1)) {
 +              void *has_data;
 +              enum object_type has_type;
 +              unsigned long has_size;
 +              has_data = read_sha1_file(sha1, &has_type, &has_size);
 +              if (!has_data)
 +                      die("cannot read existing object %s", sha1_to_hex(sha1));
 +              if (size != has_size || type != has_type ||
 +                  memcmp(data, has_data, size) != 0)
 +                      die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
 +              free(has_data);
 +      }
 +      if (strict) {
 +              if (type == OBJ_BLOB) {
 +                      struct blob *blob = lookup_blob(sha1);
 +                      if (blob)
 +                              blob->object.flags |= FLAG_CHECKED;
 +                      else
 +                              die("invalid blob object %s", sha1_to_hex(sha1));
 +              } else {
 +                      struct object *obj;
 +                      int eaten;
 +                      void *buf = (void *) data;
 +
 +                      /*
 +                       * we do not need to free the memory here, as the
 +                       * buf is deleted by the caller.
 +                       */
 +                      obj = parse_object_buffer(sha1, type, size, buf, &eaten);
 +                      if (!obj)
 +                              die("invalid %s", typename(type));
 +                      if (fsck_object(obj, 1, fsck_error_function))
 +                              die("Error in object");
 +                      if (fsck_walk(obj, mark_link, NULL))
 +                              die("Not all child objects of %s are reachable", sha1_to_hex(obj->sha1));
 +
 +                      if (obj->type == OBJ_TREE) {
 +                              struct tree *item = (struct tree *) obj;
 +                              item->buffer = NULL;
 +                      }
 +                      if (obj->type == OBJ_COMMIT) {
 +                              struct commit *commit = (struct commit *) obj;
 +                              commit->buffer = NULL;
 +                      }
 +                      obj->flags |= FLAG_CHECKED;
 +              }
 +      }
 +}
 +
 +static void *get_base_data(struct base_data *c)
 +{
 +      if (!c->data) {
 +              struct object_entry *obj = c->obj;
 +
 +              if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 +                      void *base = get_base_data(c->base);
 +                      void *raw = get_data_from_pack(obj);
 +                      c->data = patch_delta(
 +                              base, c->base->size,
 +                              raw, obj->size,
 +                              &c->size);
 +                      free(raw);
 +                      if (!c->data)
 +                              bad_object(obj->idx.offset, "failed to apply delta");
 +              } else {
 +                      c->data = get_data_from_pack(obj);
 +                      c->size = obj->size;
 +              }
 +
 +              base_cache_used += c->size;
 +              prune_base_data(c);
 +      }
 +      return c->data;
 +}
 +
 +static void resolve_delta(struct object_entry *delta_obj,
 +                        struct base_data *base, struct base_data *result)
 +{
 +      void *base_data, *delta_data;
 +
 +      delta_obj->real_type = base->obj->real_type;
 +      delta_data = get_data_from_pack(delta_obj);
 +      base_data = get_base_data(base);
 +      result->obj = delta_obj;
 +      result->data = patch_delta(base_data, base->size,
 +                                 delta_data, delta_obj->size, &result->size);
 +      free(delta_data);
 +      if (!result->data)
 +              bad_object(delta_obj->idx.offset, "failed to apply delta");
 +      sha1_object(result->data, result->size, delta_obj->real_type,
 +                  delta_obj->idx.sha1);
 +      nr_resolved_deltas++;
 +}
 +
 +static void find_unresolved_deltas(struct base_data *base,
 +                                 struct base_data *prev_base)
 +{
 +      int i, ref_first, ref_last, ofs_first, ofs_last;
 +
 +      /*
 +       * This is a recursive function. Those brackets should help reducing
 +       * stack usage by limiting the scope of the delta_base union.
 +       */
 +      {
 +              union delta_base base_spec;
 +
 +              hashcpy(base_spec.sha1, base->obj->idx.sha1);
 +              find_delta_children(&base_spec, &ref_first, &ref_last);
 +
 +              memset(&base_spec, 0, sizeof(base_spec));
 +              base_spec.offset = base->obj->idx.offset;
 +              find_delta_children(&base_spec, &ofs_first, &ofs_last);
 +      }
 +
 +      if (ref_last == -1 && ofs_last == -1) {
 +              free(base->data);
 +              return;
 +      }
 +
 +      link_base_data(prev_base, base);
 +
 +      for (i = ref_first; i <= ref_last; i++) {
 +              struct object_entry *child = objects + deltas[i].obj_no;
 +              if (child->real_type == OBJ_REF_DELTA) {
 +                      struct base_data result;
 +                      resolve_delta(child, base, &result);
 +                      if (i == ref_last && ofs_last == -1)
 +                              free_base_data(base);
 +                      find_unresolved_deltas(&result, base);
 +              }
 +      }
 +
 +      for (i = ofs_first; i <= ofs_last; i++) {
 +              struct object_entry *child = objects + deltas[i].obj_no;
 +              if (child->real_type == OBJ_OFS_DELTA) {
 +                      struct base_data result;
 +                      resolve_delta(child, base, &result);
 +                      if (i == ofs_last)
 +                              free_base_data(base);
 +                      find_unresolved_deltas(&result, base);
 +              }
 +      }
 +
 +      unlink_base_data(base);
 +}
 +
 +static int compare_delta_entry(const void *a, const void *b)
 +{
 +      const struct delta_entry *delta_a = a;
 +      const struct delta_entry *delta_b = b;
 +      return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
 +}
 +
 +/* Parse all objects and return the pack content SHA1 hash */
 +static void parse_pack_objects(unsigned char *sha1)
 +{
 +      int i;
 +      struct delta_entry *delta = deltas;
 +      struct stat st;
 +
 +      /*
 +       * First pass:
 +       * - find locations of all objects;
 +       * - calculate SHA1 of all non-delta objects;
 +       * - remember base (SHA1 or offset) for all deltas.
 +       */
 +      if (verbose)
 +              progress = start_progress(
 +                              from_stdin ? "Receiving objects" : "Indexing objects",
 +                              nr_objects);
 +      for (i = 0; i < nr_objects; i++) {
 +              struct object_entry *obj = &objects[i];
 +              void *data = unpack_raw_entry(obj, &delta->base);
 +              obj->real_type = obj->type;
 +              if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 +                      nr_deltas++;
 +                      delta->obj_no = i;
 +                      delta++;
 +              } else
 +                      sha1_object(data, obj->size, obj->type, obj->idx.sha1);
 +              free(data);
 +              display_progress(progress, i+1);
 +      }
 +      objects[i].idx.offset = consumed_bytes;
 +      stop_progress(&progress);
 +
 +      /* Check pack integrity */
 +      flush();
 +      git_SHA1_Final(sha1, &input_ctx);
 +      if (hashcmp(fill(20), sha1))
 +              die("pack is corrupted (SHA1 mismatch)");
 +      use(20);
 +
 +      /* If input_fd is a file, we should have reached its end now. */
 +      if (fstat(input_fd, &st))
 +              die_errno("cannot fstat packfile");
 +      if (S_ISREG(st.st_mode) &&
 +                      lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
 +              die("pack has junk at the end");
 +
 +      if (!nr_deltas)
 +              return;
 +
 +      /* Sort deltas by base SHA1/offset for fast searching */
 +      qsort(deltas, nr_deltas, sizeof(struct delta_entry),
 +            compare_delta_entry);
 +
 +      /*
 +       * Second pass:
 +       * - for all non-delta objects, look if it is used as a base for
 +       *   deltas;
 +       * - if used as a base, uncompress the object and apply all deltas,
 +       *   recursively checking if the resulting object is used as a base
 +       *   for some more deltas.
 +       */
 +      if (verbose)
 +              progress = start_progress("Resolving deltas", nr_deltas);
 +      for (i = 0; i < nr_objects; i++) {
 +              struct object_entry *obj = &objects[i];
 +              struct base_data base_obj;
 +
 +              if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
 +                      continue;
 +              base_obj.obj = obj;
 +              base_obj.data = NULL;
 +              find_unresolved_deltas(&base_obj, NULL);
 +              display_progress(progress, nr_resolved_deltas);
 +      }
 +}
 +
 +static int write_compressed(struct sha1file *f, void *in, unsigned int size)
 +{
 +      z_stream stream;
-       maxsize = deflateBound(&stream, size);
-       out = xmalloc(maxsize);
- 
-       /* Compress it */
++      int status;
++      unsigned char outbuf[4096];
 +
 +      memset(&stream, 0, sizeof(stream));
 +      deflateInit(&stream, zlib_compression_level);
-       stream.next_out = out;
-       stream.avail_out = maxsize;
-       while (deflate(&stream, Z_FINISH) == Z_OK);
-       deflateEnd(&stream);
 +      stream.next_in = in;
 +      stream.avail_in = size;
-       sha1write(f, out, size);
-       free(out);
 +
++      do {
++              stream.next_out = outbuf;
++              stream.avail_out = sizeof(outbuf);
++              status = deflate(&stream, Z_FINISH);
++              sha1write(f, outbuf, sizeof(outbuf) - stream.avail_out);
++      } while (status == Z_OK);
++
++      if (status != Z_STREAM_END)
++              die("unable to deflate appended object (%d)", status);
 +      size = stream.total_out;
++      deflateEnd(&stream);
 +      return size;
 +}
 +
 +static struct object_entry *append_obj_to_pack(struct sha1file *f,
 +                             const unsigned char *sha1, void *buf,
 +                             unsigned long size, enum object_type type)
 +{
 +      struct object_entry *obj = &objects[nr_objects++];
 +      unsigned char header[10];
 +      unsigned long s = size;
 +      int n = 0;
 +      unsigned char c = (type << 4) | (s & 15);
 +      s >>= 4;
 +      while (s) {
 +              header[n++] = c | 0x80;
 +              c = s & 0x7f;
 +              s >>= 7;
 +      }
 +      header[n++] = c;
 +      crc32_begin(f);
 +      sha1write(f, header, n);
 +      obj[0].size = size;
 +      obj[0].hdr_size = n;
 +      obj[0].type = type;
 +      obj[0].real_type = type;
 +      obj[1].idx.offset = obj[0].idx.offset + n;
 +      obj[1].idx.offset += write_compressed(f, buf, size);
 +      obj[0].idx.crc32 = crc32_end(f);
 +      sha1flush(f);
 +      hashcpy(obj->idx.sha1, sha1);
 +      return obj;
 +}
 +
 +static int delta_pos_compare(const void *_a, const void *_b)
 +{
 +      struct delta_entry *a = *(struct delta_entry **)_a;
 +      struct delta_entry *b = *(struct delta_entry **)_b;
 +      return a->obj_no - b->obj_no;
 +}
 +
 +static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
 +{
 +      struct delta_entry **sorted_by_pos;
 +      int i, n = 0;
 +
 +      /*
 +       * Since many unresolved deltas may well be themselves base objects
 +       * for more unresolved deltas, we really want to include the
 +       * smallest number of base objects that would cover as much delta
 +       * as possible by picking the
 +       * trunc deltas first, allowing for other deltas to resolve without
 +       * additional base objects.  Since most base objects are to be found
 +       * before deltas depending on them, a good heuristic is to start
 +       * resolving deltas in the same order as their position in the pack.
 +       */
 +      sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
 +      for (i = 0; i < nr_deltas; i++) {
 +              if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
 +                      continue;
 +              sorted_by_pos[n++] = &deltas[i];
 +      }
 +      qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
 +
 +      for (i = 0; i < n; i++) {
 +              struct delta_entry *d = sorted_by_pos[i];
 +              enum object_type type;
 +              struct base_data base_obj;
 +
 +              if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
 +                      continue;
 +              base_obj.data = read_sha1_file(d->base.sha1, &type, &base_obj.size);
 +              if (!base_obj.data)
 +                      continue;
 +
 +              if (check_sha1_signature(d->base.sha1, base_obj.data,
 +                              base_obj.size, typename(type)))
 +                      die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
 +              base_obj.obj = append_obj_to_pack(f, d->base.sha1,
 +                                      base_obj.data, base_obj.size, type);
 +              find_unresolved_deltas(&base_obj, NULL);
 +              display_progress(progress, nr_resolved_deltas);
 +      }
 +      free(sorted_by_pos);
 +}
 +
 +static void final(const char *final_pack_name, const char *curr_pack_name,
 +                const char *final_index_name, const char *curr_index_name,
 +                const char *keep_name, const char *keep_msg,
 +                unsigned char *sha1)
 +{
 +      const char *report = "pack";
 +      char name[PATH_MAX];
 +      int err;
 +
 +      if (!from_stdin) {
 +              close(input_fd);
 +      } else {
 +              fsync_or_die(output_fd, curr_pack_name);
 +              err = close(output_fd);
 +              if (err)
 +                      die_errno("error while closing pack file");
 +      }
 +
 +      if (keep_msg) {
 +              int keep_fd, keep_msg_len = strlen(keep_msg);
 +
 +              if (!keep_name)
 +                      keep_fd = odb_pack_keep(name, sizeof(name), sha1);
 +              else
 +                      keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
 +
 +              if (keep_fd < 0) {
 +                      if (errno != EEXIST)
 +                              die_errno("cannot write keep file '%s'",
 +                                        keep_name);
 +              } else {
 +                      if (keep_msg_len > 0) {
 +                              write_or_die(keep_fd, keep_msg, keep_msg_len);
 +                              write_or_die(keep_fd, "\n", 1);
 +                      }
 +                      if (close(keep_fd) != 0)
 +                              die_errno("cannot close written keep file '%s'",
 +                                  keep_name);
 +                      report = "keep";
 +              }
 +      }
 +
 +      if (final_pack_name != curr_pack_name) {
 +              if (!final_pack_name) {
 +                      snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
 +                               get_object_directory(), sha1_to_hex(sha1));
 +                      final_pack_name = name;
 +              }
 +              if (move_temp_to_file(curr_pack_name, final_pack_name))
 +                      die("cannot store pack file");
 +      } else if (from_stdin)
 +              chmod(final_pack_name, 0444);
 +
 +      if (final_index_name != curr_index_name) {
 +              if (!final_index_name) {
 +                      snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
 +                               get_object_directory(), sha1_to_hex(sha1));
 +                      final_index_name = name;
 +              }
 +              if (move_temp_to_file(curr_index_name, final_index_name))
 +                      die("cannot store index file");
 +      } else
 +              chmod(final_index_name, 0444);
 +
 +      if (!from_stdin) {
 +              printf("%s\n", sha1_to_hex(sha1));
 +      } else {
 +              char buf[48];
 +              int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
 +                                 report, sha1_to_hex(sha1));
 +              write_or_die(1, buf, len);
 +
 +              /*
 +               * Let's just mimic git-unpack-objects here and write
 +               * the last part of the input buffer to stdout.
 +               */
 +              while (input_len) {
 +                      err = xwrite(1, input_buffer + input_offset, input_len);
 +                      if (err <= 0)
 +                              break;
 +                      input_len -= err;
 +                      input_offset += err;
 +              }
 +      }
 +}
 +
 +static int git_index_pack_config(const char *k, const char *v, void *cb)
 +{
 +      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;
 +      }
 +      return git_default_config(k, v, cb);
 +}
 +
 +int cmd_index_pack(int argc, const char **argv, const char *prefix)
 +{
 +      int i, fix_thin_pack = 0;
 +      const char *curr_pack, *curr_index;
 +      const char *index_name = NULL, *pack_name = NULL;
 +      const char *keep_name = NULL, *keep_msg = NULL;
 +      char *index_name_buf = NULL, *keep_name_buf = NULL;
 +      struct pack_idx_entry **idx_objects;
 +      unsigned char pack_sha1[20];
 +
 +      if (argc == 2 && !strcmp(argv[1], "-h"))
 +              usage(index_pack_usage);
 +
 +      /*
 +       * We wish to read the repository's config file if any, and
 +       * for that it is necessary to call setup_git_directory_gently().
 +       * However if the cwd was inside .git/objects/pack/ then we need
 +       * to go back there or all the pack name arguments will be wrong.
 +       * And in that case we cannot rely on any prefix returned by
 +       * setup_git_directory_gently() either.
 +       */
 +      {
 +              char cwd[PATH_MAX+1];
 +              int nongit;
 +
 +              if (!getcwd(cwd, sizeof(cwd)-1))
 +                      die("Unable to get current working directory");
 +              setup_git_directory_gently(&nongit);
 +              git_config(git_index_pack_config, NULL);
 +              if (chdir(cwd))
 +                      die("Cannot come back to cwd");
 +      }
 +
 +      for (i = 1; i < argc; i++) {
 +              const char *arg = argv[i];
 +
 +              if (*arg == '-') {
 +                      if (!strcmp(arg, "--stdin")) {
 +                              from_stdin = 1;
 +                      } else if (!strcmp(arg, "--fix-thin")) {
 +                              fix_thin_pack = 1;
 +                      } else if (!strcmp(arg, "--strict")) {
 +                              strict = 1;
 +                      } else if (!strcmp(arg, "--keep")) {
 +                              keep_msg = "";
 +                      } else if (!prefixcmp(arg, "--keep=")) {
 +                              keep_msg = arg + 7;
 +                      } else if (!prefixcmp(arg, "--pack_header=")) {
 +                              struct pack_header *hdr;
 +                              char *c;
 +
 +                              hdr = (struct pack_header *)input_buffer;
 +                              hdr->hdr_signature = htonl(PACK_SIGNATURE);
 +                              hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
 +                              if (*c != ',')
 +                                      die("bad %s", arg);
 +                              hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
 +                              if (*c)
 +                                      die("bad %s", arg);
 +                              input_len = sizeof(*hdr);
 +                      } else if (!strcmp(arg, "-v")) {
 +                              verbose = 1;
 +                      } else if (!strcmp(arg, "-o")) {
 +                              if (index_name || (i+1) >= argc)
 +                                      usage(index_pack_usage);
 +                              index_name = argv[++i];
 +                      } else 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);
 +                      } else
 +                              usage(index_pack_usage);
 +                      continue;
 +              }
 +
 +              if (pack_name)
 +                      usage(index_pack_usage);
 +              pack_name = arg;
 +      }
 +
 +      if (!pack_name && !from_stdin)
 +              usage(index_pack_usage);
 +      if (fix_thin_pack && !from_stdin)
 +              die("--fix-thin cannot be used without --stdin");
 +      if (!index_name && pack_name) {
 +              int len = strlen(pack_name);
 +              if (!has_extension(pack_name, ".pack"))
 +                      die("packfile name '%s' does not end with '.pack'",
 +                          pack_name);
 +              index_name_buf = xmalloc(len);
 +              memcpy(index_name_buf, pack_name, len - 5);
 +              strcpy(index_name_buf + len - 5, ".idx");
 +              index_name = index_name_buf;
 +      }
 +      if (keep_msg && !keep_name && pack_name) {
 +              int len = strlen(pack_name);
 +              if (!has_extension(pack_name, ".pack"))
 +                      die("packfile name '%s' does not end with '.pack'",
 +                          pack_name);
 +              keep_name_buf = xmalloc(len);
 +              memcpy(keep_name_buf, pack_name, len - 5);
 +              strcpy(keep_name_buf + len - 5, ".keep");
 +              keep_name = keep_name_buf;
 +      }
 +
 +      curr_pack = open_pack_file(pack_name);
 +      parse_pack_header();
 +      objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
 +      deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
 +      parse_pack_objects(pack_sha1);
 +      if (nr_deltas == nr_resolved_deltas) {
 +              stop_progress(&progress);
 +              /* Flush remaining pack final 20-byte SHA1. */
 +              flush();
 +      } else {
 +              if (fix_thin_pack) {
 +                      struct sha1file *f;
 +                      unsigned char read_sha1[20], tail_sha1[20];
 +                      char msg[48];
 +                      int nr_unresolved = nr_deltas - nr_resolved_deltas;
 +                      int nr_objects_initial = nr_objects;
 +                      if (nr_unresolved <= 0)
 +                              die("confusion beyond insanity");
 +                      objects = xrealloc(objects,
 +                                         (nr_objects + nr_unresolved + 1)
 +                                         * sizeof(*objects));
 +                      f = sha1fd(output_fd, curr_pack);
 +                      fix_unresolved_deltas(f, nr_unresolved);
 +                      sprintf(msg, "completed with %d local objects",
 +                              nr_objects - nr_objects_initial);
 +                      stop_progress_msg(&progress, msg);
 +                      sha1close(f, tail_sha1, 0);
 +                      hashcpy(read_sha1, pack_sha1);
 +                      fixup_pack_header_footer(output_fd, pack_sha1,
 +                                               curr_pack, nr_objects,
 +                                               read_sha1, consumed_bytes-20);
 +                      if (hashcmp(read_sha1, tail_sha1) != 0)
 +                              die("Unexpected tail checksum for %s "
 +                                  "(disk corruption?)", curr_pack);
 +              }
 +              if (nr_deltas != nr_resolved_deltas)
 +                      die("pack has %d unresolved deltas",
 +                          nr_deltas - nr_resolved_deltas);
 +      }
 +      free(deltas);
 +      if (strict)
 +              check_objects();
 +
 +      idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
 +      for (i = 0; i < nr_objects; i++)
 +              idx_objects[i] = &objects[i].idx;
 +      curr_index = write_idx_file(index_name, idx_objects, nr_objects, pack_sha1);
 +      free(idx_objects);
 +
 +      final(pack_name, curr_pack,
 +              index_name, curr_index,
 +              keep_name, keep_msg,
 +              pack_sha1);
 +      free(objects);
 +      free(index_name_buf);
 +      free(keep_name_buf);
 +      if (pack_name == NULL)
 +              free((void *) curr_pack);
 +      if (index_name == NULL)
 +              free((void *) curr_index);
 +
 +      return 0;
 +}