# libarchive -- the four compression backends, driven in BOTH directions.
#
# 98-libarchive.test asserts from `bsdtar --version` that zlib, bz2lib, liblzma
# and libzstd were linked. That is a claim about the link, not about the codec:
# a backend can be present and still be wrong, and the whole reason libarchive
# is worth having here is that a caller can hand it a .tar.gz, .tar.bz2, .tar.xz
# or .tar.zst without knowing which. So each codec is exercised twice.
#
# THE SECOND DIRECTION IS THE ONE THAT CANNOT BE FAKED. Compressing and then
# decompressing with the same library proves only that it is self-consistent --
# a codec that emitted its own private framing would round-trip perfectly and
# still be unable to read anything real. This image also ships gzip, bzip2, xz
# and zstd as standalone CLIs (BRINTOS-80 / -123 / -127 and the bzip2 pickup),
# each a DIFFERENT implementation of the same format, so every codec here is
# additionally asked to read a stream one of those wrote. That is the same
# argument 96-erofs-utils.test makes with its shipped upstream-built fixture,
# obtained here without shipping a fixture at all.
#
# Payload is deliberately ~18 KiB rather than the 37 KiB its sibling uses: this
# file forks four compressors and four decompressors twice over, and process
# count against the runner's 60 s cap -- not compression work -- is what put
# 56-lz4.test and the first draft of 97-parted.test over budget.
. "$BST_LIB"
require bsdtar libarchive/bsdtar-present

T=${TMPDIR:-/tmp}/bst-libarchive-c.$$
rm -rf "$T"; mkdir -p "$T/src"

i=0
while [ $i -lt 256 ]; do
  printf 'the quick brown fox jumps over the lazy dog 0123456789 ABCDEFGHIJKLMNOP\n'
  i=$((i + 1))
done > "$T/src/compressible.txt"
printf 'libarchive fixture\n' > "$T/src/top.txt"

SRCSZ=$(wc -c < "$T/src/compressible.txt" | tr -d ' ')
bsdtar -C "$T/src" -cf "$T/plain.tar" . 2> /dev/null
TARSZ=$(wc -c < "$T/plain.tar" | tr -d ' ')

# ours <id> <bsdtar-create-flag> <tag>
#   create with libarchive, assert the result is materially smaller than the tar
#   it came from, extract with libarchive, compare byte-for-byte.
#
# The LOWER size bound is not decoration: a failed create leaves a zero-byte or
# header-only file behind, and an upper-bound-only assertion passes on it -- the
# exact way a write-side case reported green on a run where nothing was written.
ours() {
  _id=$1; _flag=$2; _tag=$3; _a=$T/ours.$_tag; _o=$T/o.$_tag
  if bsdtar -C "$T/src" -c "$_flag" -f "$_a" . 2> /dev/null; then
    bst_ok "libarchive/$_id-create"
  else
    bst_notok "libarchive/$_id-create" "bsdtar -c $_flag failed"
  fi
  _sz=$(wc -c < "$_a" 2> /dev/null | tr -d ' ')
  if [ -n "$_sz" ] && [ "$_sz" -gt 64 ] && [ "$_sz" -lt "$TARSZ" ]; then
    bst_ok "libarchive/$_id-smaller"
  else
    bst_notok "libarchive/$_id-smaller" \
      "archive is ${_sz:-absent} bytes; a real one holding a $TARSZ byte tar is >64 and <$TARSZ"
  fi
  rm -rf "$_o"; mkdir -p "$_o"
  # -x auto-detects the codec from the stream, so no flag is passed back in:
  # a decoder picked by sniffing is the one a real caller gets.
  if bsdtar -C "$_o" -xf "$_a" 2> /dev/null; then
    bst_ok "libarchive/$_id-extract"
  else
    bst_notok "libarchive/$_id-extract" "bsdtar -xf failed on our own $_tag archive"
  fi
  check "libarchive/$_id-roundtrip" cmp -s "$T/src/compressible.txt" "$_o/compressible.txt"
}

ours gzip  -z      gz
ours bzip2 -j      bz2
ours xz    -J      xz
ours zstd  --zstd  zst

# theirs <id> <tag> <compressor-cmd...>
#   compress the SAME plain tar with the image's standalone CLI, then read it
#   back with libarchive. Nothing libarchive wrote is involved in the input.
theirs() {
  _id=$1; _tag=$2; shift 2
  _a=$T/theirs.$_tag; _o=$T/t.$_tag
  if ! command -v "$1" > /dev/null 2>&1; then
    bst_skip "libarchive/$_id-foreign" "$1 is not on this image"
    return
  fi
  "$@" < "$T/plain.tar" > "$_a" 2> /dev/null
  rm -rf "$_o"; mkdir -p "$_o"
  if [ -s "$_a" ] && bsdtar -C "$_o" -xf "$_a" 2> /dev/null; then
    bst_ok "libarchive/$_id-foreign"
  else
    bst_notok "libarchive/$_id-foreign" "bsdtar could not read a $_tag stream written by $1"
  fi
  check "libarchive/$_id-foreign-content" cmp -s "$T/src/compressible.txt" "$_o/compressible.txt"
}

theirs gzip  gz  gzip  -c
theirs bzip2 bz2 bzip2 -c
theirs xz    xz  xz    -c
theirs zstd  zst zstd  -q -c

# ------------------------------------------------------------------- control
# A codec that "decompressed" anything handed to it would satisfy every foreign
# case above without doing any of the work.
#
# Non-zero bytes, deliberately: a run of ZEROES is a valid empty tar (the
# all-zero block is tar's end-of-archive marker), so a zeroes-based control goes
# red against a correct bsdtar. See the longer note in 98-libarchive.test.
i=0
while [ $i -lt 128 ]; do
  printf 'NOT-A-COMPRESSED-STREAM-%d-qwertyuiopasdfghjkl\n' "$i"
  i=$((i + 1))
done > "$T/junk.gz"
if bsdtar -tf "$T/junk.gz" > /dev/null 2>&1; then
  bst_notok libarchive/reject-junk-stream "bsdtar decoded non-archive text named .gz as an archive"
else
  bst_ok libarchive/reject-junk-stream
fi

rm -rf "$T"