#!/usr/bin/env bash
# nbdkit
# Copyright Red Hat
#
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# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# * Neither the name of Red Hat nor the names of its contributors may be
# used to endorse or promote products derived from this software without
# specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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# SUCH DAMAGE.

source ./functions.sh
set -e
set -x
set -u

requires_filter cow
requires_nbdsh_uri
requires_run

# On Windows, calling ftruncate in the cow filter fails with:
# nbdkit: memory[1]: error: ftruncate: File too large
if is_windows; then
   echo "$0: the cow filter needs to be fixed to work on Windows"
   exit 77
fi

define script <<'EOF'
# Write some pattern data to the overlay and check it reads back OK.
buf = b"abcd" * 16384
h.pwrite(buf, 32768)
zero = h.pread(32768, 0)
assert zero == bytearray(32768)
buf2 = h.pread(65536, 32768)
assert buf == buf2
EOF
export script

# Run nbdkit with the cow filter and cow-on-read.
nbdkit --filter=cow \
       memory 128K cow-on-read=true \
       --run ' nbdsh -u "$uri" -c "$script" '
