#! /bin/bash

########################################################################
#
# File:    reg_periodic
# Author:  Janis Johnson
# Date:    2002/12/28
#
# Over a range of dates at specified intervals, invoke separate tools to
# update sources, do a build, and run one or more tests. 
#
# Define these in a file whose name is the argument to this script:
#   LOW_DATE:   Date string recognized by the date command.
#   HIGH_DATE:  Date string recognized by the date command.
#   INTERVAL:   Time (in seconds) between dates for which to build.
#   REG_UPDATE: Pathname of script to update your source tree.
#   REG_BUILD:  Pathname of script to build enough of the product to run
#               the test.
#   REG_TEST:   Pathname of script to run one or more tests.
# Optional:
#   VERBOSITY:  Default is 0, to print only errors and final message.
#   DATE_IN_MSG If set to anything but 0, include the time and date in
#               messages
#   REG_STOP    Pathname of a file whose existence says to quit; default
#               is STOP in the current directory.
#
#
# Copyright (c) 2002, 2003, 2005, 2009, 2010 Free Software Foundation, Inc.
#
# This file 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; either version 3 of the License, or
# (at your option) any later version.
#
# 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; see the file COPYING3.  If not see
# <http://www.gnu.org/licenses/>.
#
########################################################################

########################################################################
# Functions
########################################################################

# Issue a message if its verbosity level is high enough.

msg() {
  test ${1} -gt ${VERBOSITY}  && return

  if [ "x${DATE_IN_MSG}" = "x" ]; then
    echo "${2}"
  else
    echo "`${DATE}`  ${2}"
  fi
}

# Issue an error message and exit with a nonzero status.

error() {
  msg 0 "error: ${1}"
  exit 1
}

# Turn seconds since the epoch into a date we can use with source
# control tools and report to the user.

make_date() {
  MADE_DATE=`${DATE} -u +"%Y-%m-%d %H:%M %Z" --date "1970-01-01 ${1} seconds"` \
    || error "make_date: date command failed"
}

# Build the components to test using sources as of a particular date and
# run a test case.  Pass each of the scripts the date that we're
# testing; the first one needs it, the others can ignore it if they want.

process_date() {
  TEST_DATE="${1}"

  ${REG_UPDATE} "${TEST_DATE}"
  if [ $? -ne 0 ]; then
    msg 0 "source update failed for ${TEST_DATE}"
    return
  fi
  ${REG_BUILD} "${TEST_DATE}"
  if [ $? -ne 0 ]; then
    msg 0 "build failed for ${TEST_DATE}"
    return
  fi
  ${REG_TEST} "${TEST_DATE}"
}
 
########################################################################
# Main program (so to speak)
########################################################################

# If DATE isn't defined, use the default date command; the configuration
# file can override this.

if [ "x${DATE}" = "x" ]; then
  DATE=date
fi

# Process the configuration file.

if [ $# -ne 1 ]; then
  echo Usage: $0 config_file
  exit 1
fi

CONFIG=${1}
if [ ! -f ${CONFIG} ]; then
  error "configuration file ${CONFIG} does not exist"
fi

# OK, the config file exists.  Source it, make sure required parameters
# are defined and their files exist, and give default values to optional
# parameters.

. ${CONFIG}

test "x${REG_UPDATE}" = "x" && error "REG_UPDATE is not defined"
test "x${REG_BUILD}" = "x" && error "REG_BUILD is not defined"
test "x${REG_TEST}" = "x" && error "REG_TEST is not defined"
test "x${INTERVAL}" = "x" && error "INTERVAL is not defined"
test -x ${REG_TEST} || error "REG_TEST is not an executable file"
test "x${VERBOSITY}" = "x" && VERBOSITY=0
test "x${REG_STOP}" = "x" && REG_STOP="STOP"

msg 2 "LOW_DATE   = ${LOW_DATE}"
msg 2 "HIGH_DATE  = ${HIGH_DATE}"
msg 2 "INTERVAL   = ${INTERVAL}"
msg 2 "REG_UPDATE = ${REG_UPDATE}"
msg 2 "REG_BUILD  = ${REG_BUILD}"
msg 2 "REG_TEST   = ${REG_TEST}"
msg 2 "VERBOSITY  = ${VERBOSITY}"

# Change the dates into seconds since the epoch.  This uses an extension
# in GNU date.

LOW_DATE=`${DATE} +%s --date "${LOW_DATE}"` || \
  error "date command failed for \"${LOW_DATE}\""
HIGH_DATE=`${DATE} +%s --date "${HIGH_DATE}"` || \
  error "date command failed for \"${LOW_DATE}\""

# Process each date in the range.

while [ ${LOW_DATE} -le ${HIGH_DATE} ]; do

  # If a file called STOP appears, stop; this allows a clean way to
  # interrupt a search.

  if [ -f ${REG_STOP} ]; then
    msg 0 "STOP file detected"
    rm -f ${REG_STOP}
    exit 1
  fi

  # Get a version of the date that is usable by tools and readable
  # by people, then process it.

  make_date ${LOW_DATE}
  process_date "${MADE_DATE}"
  let LOW_DATE=LOW_DATE+INTERVAL
done

msg 1 "done"