contrib/buildrpm

revlog: remove unnecessary cache validation in _chunks

Previously, we likely called _chunkraw() multiple times in order to
ensure it didn't change out from under us. I'm pretty certain this code
had its origins in the days where we attempted to have thread safety of
localrepository and thus revlog instances.

revlog instances are already not thread safe for writing. And, as of
Mercurial 3.6, hgweb uses a separate localrepository instance per
request, so there should only be a single thread reading a revlog at
a time. We more or less decided that attempting to make classes like
revlog thread safe is a lost cause.

So, this patch removes thread safety from _chunks. As a result, we make
one less call into _chunkraw() when the initial read isn't serviced
by the cache. This translates to savings of 4 function calls overall
and possibly prevents the creation of an additional buffer view into the
cache. I doubt this translates into any real world performance wins
because decompression will almost certainly dwarf time spent in
_chunks(). But it does make the code simpler, so it is an improvement.

#!/bin/sh -e
#
# Build a Mercurial RPM from the current repo
#
# Tested on
# - Fedora 20
# - CentOS 5
# - centOS 6

. $(dirname $0)/packagelib.sh

BUILD=1
RPMBUILDDIR="$PWD/rpmbuild"
while [ "$1" ]; do
    case "$1" in
    --prepare )
        shift
        BUILD=
        ;;
    --withpython | --with-python)
        shift
        PYTHONVER=2.7.10
        PYTHONMD5=d7547558fd673bd9d38e2108c6b42521
        ;;
    --rpmbuilddir )
        shift
        RPMBUILDDIR="$1"
        shift
        ;;
    * )
        echo "Invalid parameter $1!" 1>&2
        exit 1
        ;;
    esac
done

cd "`dirname $0`/.."

specfile=$PWD/contrib/mercurial.spec
if [ ! -f $specfile ]; then
    echo "Cannot find $specfile!" 1>&2
    exit 1
fi

if [ ! -d .hg ]; then
    echo 'You are not inside a Mercurial repository!' 1>&2
    exit 1
fi

gethgversion

# TODO: handle distance/node set, and type set

if [ -z "$type" ] ; then
   release=1
else
    release=0.9_$type
fi

if [ -n "$distance" ] ; then
    release=$release+$distance_$node
fi

if [ "$PYTHONVER" ]; then
    release=$release+$PYTHONVER
    RPMPYTHONVER=$PYTHONVER
else
    RPMPYTHONVER=%{nil}
fi

mkdir -p $RPMBUILDDIR/SOURCES
$HG archive -t tgz $RPMBUILDDIR/SOURCES/mercurial-$version-$release.tar.gz
if [ "$PYTHONVER" ]; then
(
    mkdir -p build
    cd build
    PYTHON_SRCFILE=Python-$PYTHONVER.tgz
    [ -f $PYTHON_SRCFILE ] || curl -Lo $PYTHON_SRCFILE http://www.python.org/ftp/python/$PYTHONVER/$PYTHON_SRCFILE
    if [ "$PYTHONMD5" ]; then
        echo "$PYTHONMD5 $PYTHON_SRCFILE" | md5sum -w -c
    fi
    ln -f $PYTHON_SRCFILE $RPMBUILDDIR/SOURCES/$PYTHON_SRCFILE

    DOCUTILSVER=`sed -ne "s/^%global docutilsname docutils-//p" $specfile`
    DOCUTILS_SRCFILE=docutils-$DOCUTILSVER.tar.gz
    [ -f $DOCUTILS_SRCFILE ] || curl -Lo $DOCUTILS_SRCFILE http://downloads.sourceforge.net/project/docutils/docutils/$DOCUTILSVER/$DOCUTILS_SRCFILE
    DOCUTILSMD5=`sed -ne "s/^%global docutilsmd5 //p" $specfile`
    if [ "$DOCUTILSMD5" ]; then
        echo "$DOCUTILSMD5 $DOCUTILS_SRCFILE" | md5sum -w -c
    fi
    ln -f $DOCUTILS_SRCFILE $RPMBUILDDIR/SOURCES/$DOCUTILS_SRCFILE
)
fi

mkdir -p $RPMBUILDDIR/SPECS
rpmspec=$RPMBUILDDIR/SPECS/mercurial.spec

sed -e "s,^Version:.*,Version: $version," \
    -e "s,^Release:.*,Release: $release," \
    $specfile > $rpmspec

echo >> $rpmspec
echo "%changelog" >> $rpmspec

if echo $version | grep '+' > /dev/null 2>&1; then
    latesttag="`echo $version | sed -e 's/+.*//'`"
    $HG log -r .:"$latesttag" -fM \
        --template '{date|hgdate}\t{author}\t{desc|firstline}\n' | python -c '
import sys, time

def datestr(date, format):
    return time.strftime(format, time.gmtime(float(date[0]) - date[1]))

changelog = []
for l in sys.stdin.readlines():
    tok = l.split("\t")
    hgdate = tuple(int(v) for v in tok[0].split())
    changelog.append((datestr(hgdate, "%F"), tok[1], hgdate, tok[2]))
prevtitle = ""
for l in sorted(changelog, reverse=True):
    title = "* %s %s" % (datestr(l[2], "%a %b %d %Y"), l[1])
    if prevtitle != title:
        prevtitle = title
        print
        print title
    print "- %s" % l[3].strip()
' >> $rpmspec

else

    $HG log \
         --template '{date|hgdate}\t{author}\t{desc|firstline}\n' \
         .hgtags | python -c '
import sys, time

def datestr(date, format):
    return time.strftime(format, time.gmtime(float(date[0]) - date[1]))

for l in sys.stdin.readlines():
    tok = l.split("\t")
    hgdate = tuple(int(v) for v in tok[0].split())
    print "* %s %s\n- %s" % (datestr(hgdate, "%a %b %d %Y"), tok[1], tok[2])
' >> $rpmspec

fi

sed -i \
    -e "s/^%define withpython.*$/%define withpython $RPMPYTHONVER/" \
    $rpmspec

if [ "$BUILD" ]; then
    rpmbuild --define "_topdir $RPMBUILDDIR" -ba $rpmspec --clean
    if [ $? = 0 ]; then
        echo
        echo "Built packages for $version-$release:"
        find $RPMBUILDDIR/*RPMS/ -type f -newer $rpmspec
    fi
else
    echo "Prepared sources for $version-$release $rpmspec are in $RPMBUILDDIR/SOURCES/ - use like:"
    echo "rpmbuild --define '_topdir $RPMBUILDDIR' -ba $rpmspec --clean"
fi