#define DISABLE_SIGN_COMPARE_WARNINGS

#include "git-compat-util.h"

#include "environment.h"

#include "hex.h"

#include "repository.h"

#include "pack.h"

#include "progress.h"

#include "packfile.h"

#include "object-file.h"

#include "odb.h"

#include "odb/streaming.h"

struct idx_entry {

  off_t                offset;

  unsigned int nr;

};

static int compare_entries(const void *e1, const void *e2)

{

  const struct idx_entry *entry1 = e1;

  const struct idx_entry *entry2 = e2;

  if (entry1->offset < entry2->offset)

    return -1;

  if (entry1->offset > entry2->offset)

    return 1;

  return 0;

}

int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,

       off_t offset, off_t len, unsigned int nr)

{

  const uint32_t *index_crc;

  uint32_t data_crc = crc32(0, NULL, 0);

  do {

    unsigned long avail;

    void *data = use_pack(p, w_curs, offset, &avail);

    if (avail > len)

      avail = len;

    data_crc = crc32(data_crc, data, avail);

    offset += avail;

    len -= avail;

  } while (len);

  index_crc = p->index_data;

  index_crc += 2 + 256 + (size_t)p->num_objects * (p->repo->hash_algo->rawsz/4) + nr;

  return data_crc != ntohl(*index_crc);

}

static int verify_packfile(struct repository *r,

         struct packed_git *p,

         struct pack_window **w_curs,

         verify_fn fn,

         struct progress *progress, uint32_t base_count)

{

  off_t index_size = p->index_size;

  const unsigned char *index_base = p->index_data;

  struct git_hash_ctx ctx;

  unsigned char hash[GIT_MAX_RAWSZ], *pack_sig;

  off_t offset = 0, pack_sig_ofs = 0;

  uint32_t nr_objects, i;

  int err = 0;

  struct idx_entry *entries;

  if (!is_pack_valid(p))

    return error("packfile %s cannot be accessed", p->pack_name);

  r->hash_algo->init_fn(&ctx);

  do {

    unsigned long remaining;

    unsigned char *in = use_pack(p, w_curs, offset, &remaining);

    offset += remaining;

    if (!pack_sig_ofs)

      pack_sig_ofs = p->pack_size - r->hash_algo->rawsz;

    if (offset > pack_sig_ofs)

      remaining -= (unsigned int)(offset - pack_sig_ofs);

    git_hash_update(&ctx, in, remaining);

  } while (offset < pack_sig_ofs);

  git_hash_final(hash, &ctx);

  pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);

  if (!hasheq(hash, pack_sig, r->hash_algo))

    err = error("%s pack checksum mismatch",

          p->pack_name);

  if (!hasheq(index_base + index_size - r->hash_algo->hexsz, pack_sig,

        r->hash_algo))

    err = error("%s pack checksum does not match its index",

          p->pack_name);

  unuse_pack(w_curs);

  /* Make sure everything reachable from idx is valid.  Since we

   * have verified that nr_objects matches between idx and pack,

   * we do not do scan-streaming check on the pack file.

   */

  nr_objects = p->num_objects;

  ALLOC_ARRAY(entries, nr_objects + 1);

  entries[nr_objects].offset = pack_sig_ofs;

  /* first sort entries by pack offset, since unpacking them is more efficient that way */

  for (i = 0; i < nr_objects; i++) {

    entries[i].offset = nth_packed_object_offset(p, i);

    entries[i].nr = i;

  }

  QSORT(entries, nr_objects, compare_entries);

  for (i = 0; i < nr_objects; i++) {

    struct odb_read_stream *stream = NULL;

    void *data;

    struct object_id oid;

    enum object_type type;

    unsigned long size;

    off_t curpos;

    int data_valid;

    if (nth_packed_object_id(&oid, p, entries[i].nr) < 0)

      BUG("unable to get oid of object %lu from %s",

          (unsigned long)entries[i].nr, p->pack_name);

    if (p->index_version > 1) {

      off_t offset = entries[i].offset;

      off_t len = entries[i+1].offset - offset;

      unsigned int nr = entries[i].nr;

      if (check_pack_crc(p, w_curs, offset, len, nr))

        err = error("index CRC mismatch for object %s "

              "from %s at offset %"PRIuMAX"",

              oid_to_hex(&oid),

              p->pack_name, (uintmax_t)offset);

    }

    curpos = entries[i].offset;

    type = unpack_object_header(p, w_curs, &curpos, &size);

    unuse_pack(w_curs);

    if (type == OBJ_BLOB &&

        repo_settings_get_big_file_threshold(r) <= size) {

      /*

       * Let stream_object_signature() check it with

       * the streaming interface; no point slurping

       * the data in-core only to discard.

       */

      data = NULL;

      data_valid = 0;

    } else {

      data = unpack_entry(r, p, entries[i].offset, &type, &size);

      data_valid = 1;

    }

    if (data_valid && !data)

      err = error("cannot unpack %s from %s at offset %"PRIuMAX"",

            oid_to_hex(&oid), p->pack_name,

            (uintmax_t)entries[i].offset);

    else if (data && check_object_signature(r, &oid, data, size,

              type) < 0)

      err = error("packed %s from %s is corrupt",

            oid_to_hex(&oid), p->pack_name);

    else if (!data &&

       (packfile_read_object_stream(&stream, &oid, p, entries[i].offset) < 0 ||

        stream_object_signature(r, stream, &oid) < 0))

      err = error("packed %s from %s is corrupt",

            oid_to_hex(&oid), p->pack_name);

    else if (fn) {

      int eaten = 0;

      err |= fn(&oid, type, size, data, &eaten);

      if (eaten)

        data = NULL;

    }

    if (((base_count + i) & 1023) == 0)

      display_progress(progress, base_count + i);

    if (stream)

      odb_read_stream_close(stream);

    free(data);

  }

  display_progress(progress, base_count + i);

  free(entries);

  return err;

}

int verify_pack_index(struct packed_git *p)

{

  int err = 0;

  if (open_pack_index(p))

    return error("packfile %s index not opened", p->pack_name);

  /* Verify SHA1 sum of the index file */

  if (!hashfile_checksum_valid(p->repo->hash_algo, p->index_data, p->index_size))

    err = error("Packfile index for %s hash mismatch",

          p->pack_name);

  return err;

}

int verify_pack(struct repository *r, struct packed_git *p, verify_fn fn,

    struct progress *progress, uint32_t base_count)

{

  int err = 0;

  struct pack_window *w_curs = NULL;

  err |= verify_pack_index(p);

  if (!p->index_data)

    return -1;

  err |= verify_packfile(r, p, &w_curs, fn, progress, base_count);

  unuse_pack(&w_curs);

  return err;

}