mfctxt

#!/bin/sh

usage()
{
    cat >&2 <<__EOF__
Usage: $(basename $0) [ -o outfile ] revision1 [ revision2 ] ...

Options:
  -o outfile       -- The file to which the MFC commit message should be
                      written. Defaults to ./mfc.txt.
  revision         -- A Subversion commit revision number corresponding to
                      a commit in HEAD. At least one revision must be
                      specified.
Environment variables:
  SVNSRCBASE       -- Root of a checkout of the FreeBSD Subversion repository.
                      Defaults to \${HOME}/src/freebsd-svn.
__EOF__
    exit ${1-1}
}

log()
{
    echo "$(basename $0): $1" >&2
}

REVS=
SVNSRCBASE=${SVNSRCBASE-${HOME}/src/freebsd-svn}

while [ $# -gt 0 ]; do
    case $1 in
    -h|--help)
        usage 0
        ;;
    -o)
        shift; OUTF="$1"
        ;;
    *)
        if [ -z "$REVS" ]; then
            REVS="$1"
        else
            REVS="$REVS $1"
        fi
        ;;
    esac
    shift
done

OUTF=${OUTF-mfc.txt}

if [ -z "$REVS" ]; then
    usage
elif ! which svn >/dev/null 2>&1; then
    log "Subversion isn't installed. Exiting."
    exit 1
elif [ -f "$OUTF" ] && ! [ -w "$OUTF" ]; then
    log "Outfile '$OUTF' exists and isn't writable. Exiting."
    exit 1
elif ! svn status "$SVNSRCBASE/head" >/dev/null 2>&1; then
    log "Failed to access the FreeBSD Subversion repository. Exiting."
    exit 1
fi

if [ -f "$OUTF" ]; then
    backup=$(mktemp -t $(basename $0))
    if [ -z "$backup" ]; then
        log "Failed to create temporary file. Exiting."
        exit 1
    fi
    log "Warning: outfile '$OUTF' already exists. Backing it up to ${backup}."
    cp -f "$OUTF" $backup
    truncate -s 0 "$OUTF"
fi

TMPREVS=
for rev in $REVS; do
    if ! expr $rev : r >/dev/null 2>&1; then
        TMPREVS="$TMPREVS r${rev}"
    else
        TMPREVS="$TMPREVS $rev"
    fi
done
REVS=$TMPREVS

if [ $(echo $REVS | awk '{print NF}') -gt 1 ]; then
    echo "MFC ${REVS# *}." >> "$OUTF"
    echo >> "$OUTF"
fi

for rev in $REVS; do
    logf=$(mktemp -t $(basename $0))
    if [ -z "$logf" ]; then
        log "Failed to create a temporary file. Exiting."
        rm -f "$OUTF"
        exit 1
    fi
    svn log -r $rev "$SVNSRCBASE/head" > $logf 2>/dev/null
    if [ $? -ne 0 ]; then
        log "Warning: couldn't fetch log for revision '$rev', skipping."
        rm -f $logf
        continue
    elif [ "$(wc -l $logf | awk '{print $1}')" = 1 ]; then
        log "Warning: it looks like revision '$rev' belongs to another branch, skipping."
        rm -f $logf
        continue
    fi

    echo "MFC $rev:" >> "$OUTF"
    cat $logf | sed -e 1,3d -e '$d' -e '/^Approved by:/d' \
                                    -e '/^MFC after:/d' \
                                    -e '/^PR:/d' \
                                    -e '/^Reported by:/d' \
                                    -e '/^Reviewed by:/d' \
                                    -e '/^Sponsored by:/d' \
                                    -e '/^Submitted by:/d' \
                                    -e '/^Tested by:/d' >> "$OUTF"
    rm -f $logf
done

sed -i '' '$d' "$OUTF"