git/t/lib-pack.sh
Jonathan Nieder c74c72034f test: replace shebangs with descriptions in shell libraries
A #! line in these files is misleading, since these scriptlets are
meant to be sourced with '.' (using whatever shell sources them)
instead of run directly using the interpreter named on the #! line.

Removing the #! line shouldn't hurt syntax highlighting since
these files have filenames ending with '.sh'.  For documentation,
add a brief description of how the files are meant to be used in
place of the shebang line.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-11-26 14:23:52 -08:00

99 lines
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# Support routines for hand-crafting weird or malicious packs.
#
# You can make a complete pack like:
#
# pack_header 2 >foo.pack &&
# pack_obj e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 >>foo.pack &&
# pack_obj e68fe8129b546b101aee9510c5328e7f21ca1d18 >>foo.pack &&
# pack_trailer foo.pack
# Print the big-endian 4-byte octal representation of $1
uint32_octal () {
n=$1
printf '\\%o' $(($n / 16777216)); n=$((n % 16777216))
printf '\\%o' $(($n / 65536)); n=$((n % 65536))
printf '\\%o' $(($n / 256)); n=$((n % 256))
printf '\\%o' $(($n ));
}
# Print the big-endian 4-byte binary representation of $1
uint32_binary () {
printf "$(uint32_octal "$1")"
}
# Print a pack header, version 2, for a pack with $1 objects
pack_header () {
printf 'PACK' &&
printf '\0\0\0\2' &&
uint32_binary "$1"
}
# Print the pack data for object $1, as a delta against object $2 (or as a full
# object if $2 is missing or empty). The output is suitable for including
# directly in the packfile, and represents the entirety of the object entry.
# Doing this on the fly (especially picking your deltas) is quite tricky, so we
# have hardcoded some well-known objects. See the case statements below for the
# complete list.
pack_obj () {
case "$1" in
# empty blob
e69de29bb2d1d6434b8b29ae775ad8c2e48c5391)
case "$2" in
'')
printf '\060\170\234\003\0\0\0\0\1'
return
;;
esac
;;
# blob containing "\7\76"
e68fe8129b546b101aee9510c5328e7f21ca1d18)
case "$2" in
'')
printf '\062\170\234\143\267\3\0\0\116\0\106'
return
;;
01d7713666f4de822776c7622c10f1b07de280dc)
printf '\165\1\327\161\66\146\364\336\202\47\166' &&
printf '\307\142\54\20\361\260\175\342\200\334\170' &&
printf '\234\143\142\142\142\267\003\0\0\151\0\114'
return
;;
esac
;;
# blob containing "\7\0"
01d7713666f4de822776c7622c10f1b07de280dc)
case "$2" in
'')
printf '\062\170\234\143\147\0\0\0\20\0\10'
return
;;
e68fe8129b546b101aee9510c5328e7f21ca1d18)
printf '\165\346\217\350\22\233\124\153\20\32\356' &&
printf '\225\20\305\62\216\177\41\312\35\30\170\234' &&
printf '\143\142\142\142\147\0\0\0\53\0\16'
return
;;
esac
;;
esac
echo >&2 "BUG: don't know how to print $1${2:+ (from $2)}"
return 1
}
# Compute and append pack trailer to "$1"
pack_trailer () {
test-sha1 -b <"$1" >trailer.tmp &&
cat trailer.tmp >>"$1" &&
rm -f trailer.tmp
}
# Remove any existing packs to make sure that
# whatever we index next will be the pack that we
# actually use.
clear_packs () {
rm -f .git/objects/pack/*
}