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git/t/lib-pack.sh
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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/* | |
} |