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Diffstat (limited to 'third_party/git/t/lib-pack.sh')
| -rw-r--r-- | third_party/git/t/lib-pack.sh | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/third_party/git/t/lib-pack.sh b/third_party/git/t/lib-pack.sh new file mode 100644 index 000000000000..c4d907a450a7 --- /dev/null +++ b/third_party/git/t/lib-pack.sh @@ -0,0 +1,110 @@ +# 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 + + # If it's not a delta, we can convince pack-objects to generate a pack + # with just our entry, and then strip off the header (12 bytes) and + # trailer (20 bytes). + if test -z "$2" + then + echo "$1" | git pack-objects --stdout >pack_obj.tmp && + size=$(wc -c <pack_obj.tmp) && + dd if=pack_obj.tmp bs=1 count=$((size - 20 - 12)) skip=12 && + rm -f pack_obj.tmp + return + fi + + 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-tool 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/* +} |