revlog: break up compression of large deltas
Python's zlib apparently makes an internal copy of strings passed to
compress(). To avoid this, compress strings 1M at a time, then join
them at the end if the result would be smaller than the original.
For initial commits of large but compressible files, this cuts peak
memory usage nearly in half.
#!/bin/sh
#
# This is an example of using HGEDITOR to create of diff to review the
# changes while commiting.
# If you want to pass your favourite editor some other parameters
# only for Mercurial, modify this:
case "${EDITOR}" in
"")
EDITOR="vi"
;;
emacs)
EDITOR="$EDITOR -nw"
;;
gvim|vim)
EDITOR="$EDITOR -f -o"
;;
esac
HGTMP=""
cleanup_exit() {
rm -rf "$HGTMP"
}
# Remove temporary files even if we get interrupted
trap "cleanup_exit" 0 # normal exit
trap "exit 255" 1 2 3 6 15 # HUP INT QUIT ABRT TERM
HGTMP="${TMPDIR-/tmp}/hgeditor.$RANDOM.$RANDOM.$RANDOM.$$"
(umask 077 && mkdir "$HGTMP") || {
echo "Could not create temporary directory! Exiting." 1>&2
exit 1
}
(
grep '^HG: changed' "$1" | cut -b 13- | while read changed; do
"$HG" diff "$changed" >> "$HGTMP/diff"
done
)
cat "$1" > "$HGTMP/msg"
MD5=$(which md5sum 2>/dev/null) || \
MD5=$(which md5 2>/dev/null)
[ -x "${MD5}" ] && CHECKSUM=`${MD5} "$HGTMP/msg"`
if [ -s "$HGTMP/diff" ]; then
$EDITOR "$HGTMP/msg" "$HGTMP/diff" || exit $?
else
$EDITOR "$HGTMP/msg" || exit $?
fi
[ -x "${MD5}" ] && (echo "$CHECKSUM" | ${MD5} -c >/dev/null 2>&1 && exit 13)
mv "$HGTMP/msg" "$1"
exit $?