file filter

ff

#!/usr/bin/env bash

check_perm() {
  local path="$1"
  local min="$2"
  local max="$3"
  local owner="$4"
  local group="$5"
  local stat=( $(stat -L -c "0%#a %U %G" $path 2>/dev/null) )
  local fperm=${stat[0]}
  local fowner=${stat[1]}
  local fgroup=${stat[2]}
  printf -v _min "%o" $((~0$fperm & 0${min:-0550}))
  printf -v _max "%o" $((0$fperm & ~0${max:-0770}))
  #printf "%s\n" "$path $min $max $owner $group | $fperm $fowner $fgroup | ~0$fperm & 0${min:-0550} = $_min | 0$fperm & ~0${max:-0770} = $_max"
  [ $_min -eq 0 ] || return 11
  [ $_max -eq 0 ] || return 12
  [ "$(id -u $owner 2>/dev/null)" == $(id -u $fowner 2>/dev/null) ] || return 15
  [ "$(id -g $group 2>/dev/null)" == $(id -g $fgroup 2>/dev/null) ] || return 16
  return 0
}

die() {
  local msg=$1
  local errcode=$2
  local err
  case "$errcode" in
    11) err="min perm";;
    12) err="max perm";;
    13) err="running user";;
    14) err="running group";;
    15) err="file owner";;
    16) err="file group";;
     *) err="undefined error";;
  esac
  printf "%s: %s (%s)\n" "$msg" "$err" "$errcode"
  exit
}

wait_file() {
  is_file $1 || return 1
  test -f ${1%/*}/.#${1##*/} || ln $1 ${1%/*}/.#${1##*/} 2>/dev/null
  while [[ -f $1 && -n $(lsof $1 2>/dev/null) ]]; do :; done
  rm -f ${1%/*}/.#${1##*/}
}

ff() {
  local file=$1
  local dst=$2
  file=${file## }
  wait_file $file || return
  local now=$(date +%s.%N)
  local mod=$(stat -c%.Y $file 2>/dev/null) && ((${mod/./})) || return
  printf "%s found %s: %s -> %s (%.9f)\n" ${FUNCNAME[2]} $file $mod $now $((${now/./}-${mod/./}))e-9
  pass_tests ${FF_FAIL} "$file" && move "$file" "$dst" || move "$file" "$quarantine"
}

incorrect_perm() { die "incorrect permissions or directory ownership on $1" $2; }

iwatch() {
  if [[ -z $iwatch_fd ]] || ! kill -0 $iwatch_pid &>/dev/null; then
    fifo=$(mktemp -u)
    mkfifo $fifo
    exec {iwatch_fd}<>$fifo
    inotifywait -m -q -e create -e moved_to --format " %w%f" "$1" > $fifo &
    iwatch_pid=$!
    rm -f $fifo
    echo "iwatch started ($iwatch_pid:$iwatch_fd)"
    trap "kill $iwatch_pid $swatch_pid &>/dev/null; exit" 0 INT QUIT TERM
  fi
  read -n 256 -t .005 -u $iwatch_fd file
  read_file "$file" "$2"
}

write_slowly() {
  exec {_write_slowly}> "$1"
  while read -n ${2:-2048} bytes; do
    [[ -n $bytes ]] && echo -n $bytes 1>&${_write_slowly} || echo 1>&${_write_slowly}
    sleep ${3:-.01}
  done
  eval "exec ${_write_slowly}>&-"
}

min_age() {
  local min_age file=$2 now=${3:-$(date +%s.%N)}
  local file_mod=$(stat -c%.Y "$file" 2>/dev/null || echo -1)
  [[ $file_mod == -1 ]] && return 1
  printf -v min_age %.9f $1
  (((${now/./}-${file_mod/./}) > ${min_age/./}))
}

dir_empty() {
  shopt -s nullglob
  local remaining=($1/*)
  ((!${#remaining[@]}))
}

is_file() {
  [[ -f $1 ]] || return 1
  [[ "${1##*/}" =~ ^\. ]] && return 1
  [[ -f ${1%/*}/.#${1##*/} ]] && return 1
  return 0
}

swatch() {
  if [[ -z $swatch_fd ]] || ! kill -0 $swatch_pid &>/dev/null; then
    local fifo=$(mktemp -u)
    mkfifo $fifo
    exec {swatch_fd}<>$fifo
    while sleep .1 && kill -0 $$ &>/dev/null; do
      dir_empty $1 && continue
      local now=$(date +%s.%N)
      for file in $1/*; do
        is_file $file && min_age 0 $file $now && echo $file
      done
    done > $fifo &
    swatch_pid=$!
    rm -f $fifo
    echo "swatch started ($swatch_pid:$swatch_fd)"
    trap "kill $swatch_pid $iwatch_pid &>/dev/null; exit" 0 INT QUIT TERM
  fi
  read -n 256 -t .1 -u $swatch_fd file
  read_file "$file" "$2"
}

read_file() {
  err=$?
  [[ -n $1 && -n $2 ]] || return 1
  ((err>=129)) && err=129
  case $err in
    0) ff "$1" "$2" &;;
    129) true;;
    *) false;;
  esac
}

move() {
  mkdir -p "$2" || return 1
  test -d "$2" || return 1
  local hidden="$2/.#${1##*/}"
  mv -f "$1" "$hidden" &>/dev/null || return
  chown --reference="$2" "$hidden" &>/dev/null || return
  chmod --reference="$2" "$hidden" &>/dev/null || return
  chmod -x "$hidden" &>/dev/null || return
  mv -f "$hidden" "$2/${1##*/}" &>/dev/null || return
  printf "'%s' -> '%s' (%s)\n" "$1" "$2/${1##*/}" ${FUNCNAME[3]}
  rm -f ${1%/*}/.#${1##*/}
}

pass_tests() {
  local fail=$1; shift
  local file=$1; shift
  for test in "${tests[@]}"; do
    type "$test" &>/dev/null || case "${fail:-safe}" in
      lock) return 1;;
      safe) continue;;
    esac
    test -f "$file"
    echo "$test $file"
    $test "$file" &>/dev/null || return 1
  done
  return 0
}

umask 0000
tests=()
while getopts "d:o:q:s:t:" o; do
  case "$o" in
    d)
      #path[:0550:0770[:owner:group]]
      DST=(${OPTARG//:/ })
      test -n "${DST[0]}" -a -d "${DST[0]}" || die "dst path not a directory"
      dst="${DST[0]}"
      check_perm "${DST[@]}" || incorrect_perm ${DST[0]} $?
      ;;
    o)
      owner=(${OPTARG/:/ })
      [ "$(id -u 2>/dev/null)" == "$(id -u ${owner[0]} 2>/dev/null)" ] || die error 13
      [ "$(id -g 2>/dev/null)" == "$(id -g ${owner[1]} 2>/dev/null)" ] || die error 14
      ;;
    q) quarantine=$OPTARG;;
    s)
      #path[:0550:0770[:owner:group]]
      SRC=(${OPTARG//:/ })
      test -n "${SRC[0]}" -a -d "${SRC[0]}" || die "src path not a directory"
      src="${SRC[0]}"
      check_perm "${SRC[@]}" || incorrect_perm ${SRC[@]} $?
      ;;
    t)
      unset -f "$OPTARG"
      tests+=($OPTARG)
      ;;
  esac
done
shift $(($OPTIND-1))
[ -n "$dst" ] || die "dst path not set"
[ -n "$src" ] || die "src path not set"
: ${quarantine:=$dst-quarantine}

for conf in ${FF_CONF:-./ff.conf} /etc/ff.conf; do test -f $conf || continue; source $conf && echo "Loaded $conf" && break; done
for test in "${tests[@]}"; do declare -f "$test" &>/dev/null && echo "Found test: $test" || die "no func $test"; done

shopt -s nullglob
for file in $src/.#*; do
  [[ -f $file ]] || continue
  h=$(stat -c%h $file 2>/dev/null || echo 0)
  (($h>1)) && rm -f $file
done

while :; do
  iwatch "$src" "$dst"
  swatch "$src" "$dst"
done