#!/bin/bash
#
# See $desc, below, for program description
#
# Copyright (c) 2013 Red Hat, Inc.
#
# Author(s):
#   Jeff Cody <jcody@redhat.com>
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; under version 2 of the license
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, see <http://www.gnu.org/licenses/gpl-2.0.html>.
#

set -C -u -e
set -o pipefail

desc="
$0 iterates through a git commit range, and performs the
following on each commit:
  - git checkout
  - make clean
  - configure
  - make

It will also optionally perform a git-reset and git-clean between
checkouts, if requested via the '-f' option.

The script will exit and report on first error on any of the above steps,
(except no error checking is performed on 'make clean')

NOTE: While executing, the script will checkout out each commit
      in the range in the current git tree.  On exit, the HEAD
      at the time the script was called is checked out"


# default range is the last commit
def_range="HEAD^!"
def_config_opt="--target-list=x86_64-softmmu"
# you may want to have make perform multiple jobs, e.g. -j4
# this is ommitted as the default in case the project makefile
# is not safe for parallel make processes
def_make_opt=""
def_log="output-$$.log"
def_logdir=""
force_clean='n'

logfile=$def_log
range=`git config compile-check.range || true`
config_opt=`git config compile-check.configopt || true`
make_opt=`git config compile-check.makeopt || true`
logdir=`git config compile-check.logdir || true`

if [[ -z "$range" ]]
then
    range=$def_range
    git config compile-check.range $range || true
fi
if [[ -z "$config_opt" ]]
then
    config_opt=$def_config_opt
    git config compile-check.configopt $config_opt || true
fi
if [[ -z "$make_opt" ]]
then
    make_opt=$def_make_opt
    git config compile-check.makeopt $make_opt || true
fi
if [[ -z "$logdir" ]]
then
    logdir=$def_logdir
    git config compile-check.logdir $logdir || true
fi

usage() {
    echo ""
    echo "$0 [OPTIONS]"
    echo "$desc"
    echo ""
    echo "OPTIONS:"
    echo "      -r git range
            optional; default is '$range'
"
    echo "      -c configure options
            optional; default is '$config_opt'
"
    echo "      -m make options
            optional; default is '$make_opt'
"
    echo "      -d log dir
            optional; default is '$logdir'
"
    echo "      -l log filename
            optional; default is output-PROCID, where PROCID is the bash process id
            note: you may specify a full path for the log filename here, and exclude the
            -d option.
"
    echo "      -f force a git reset and clean
            this will cause a 'git reset --hard; git clean -fdx' to be run between checkouts.
            !! WARNING: This may cause data loss in your git tree.
                        READ the git-clean and git-reset man pages and make
                        sure you understand the implications of
                        'git clean -fdx' and 'git reset --hard' before using !!
            If you specify this option, make sure the logfile falls outside of the tree.
"
    echo "      -h help"
}

while getopts ":r:c:m:l:d:hf" opt
do
    case $opt in
        r) range=$OPTARG
            ;;
        c) config_opt=$OPTARG
            ;;
        m) make_opt=$OPTARG
            ;;
        d) logdir=$OPTARG
            ;;
        l) logfile=$OPTARG
            ;;
        f) force_clean='y'
            ;;
        h) usage
           exit
            ;;
        \?) echo "Unknown option: -$OPTARG" >&2
            usage
            exit 1
            ;;
    esac
done

# append a '/' to logdir if $logdir was specified without one
[[ -n "$logdir" ]] && [[ ${logdir:${#logdir}-1} != "/" ]] && logdir="${logdir}/"

logfile="${logdir}${logfile}"

head=`git rev-parse --abbrev-ref=strict HEAD`
if [ HEAD = "$head" ]
then
    # we're at a detached head, get hash
    head=`git rev-parse HEAD`
fi


total=`git rev-list "$range" |wc -l`

echo "log output: $logfile"

rm -f "$logfile"
date > "$logfile"
echo "git compile check for $range." >> "$logfile"
echo "* configure options='$config_opt'" >> "$logfile"
echo "* make options='$make_opt'" >> "$logfile"
echo "Performing a test compile on $total patches" | tee -a "$logfile"
echo "-------------------------------------------------------------" >> "$logfile"
echo "" | tee -a "$logfile"

clean_repo() {
    if [[ $force_clean == 'y' ]]
    then
        git reset --hard >> "$logfile" 2>&1 || true
        git clean -fdx   >> "$logfile" 2>&1 || true
    fi
}

# we want to cleanup and return the git tree back to the previous head
trap cleanup EXIT

cleanup() {
    echo ""
    echo -n "Cleaning up..."
    clean_repo
    git checkout $head > /dev/null 2>&1
    echo "done."
}

cnt=1
# don't pipe the git job into read, to avoid subshells
while read hash
do
    txt=`git log --pretty=tformat:"%h: %s" $hash^!`
    echo "${cnt}/${total}: compiling: $txt" | tee -a "$logfile"
    let cnt=$cnt+1;
    echo "####################" >> "$logfile"
    clean_repo
    make clean > /dev/null 2>&1 || true
    git checkout $hash          >> "$logfile" 2>&1 && \
        ./configure $config_opt >> "$logfile" 2>&1 && \
        make $make_opt          >> "$logfile" 2>&1 ||
    (
        S=$?
        # don't complain for SIGINT, SIGTERM, SIGQUIT
        if [ $S -ne 130 ] && [ $S -ne 131 ] && [ $S -ne 143 ]
        then
            echo "" | tee -a "$logfile"
            echo "ERROR: commit $hash failed to build!" | tee -a "$logfile"
            git show --stat $hash | tee -a "$logfile"
        fi
        exit 1
    )
done < <(git log $range --pretty=tformat:"%H" --reverse)

echo "
All patches in $range compiled successfully!" | tee -a "$logfile"
exit 0