# Copyright (c) 2006 The Regents of The University of Michigan
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met: redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer;
# redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution;
# neither the name of the copyright holders nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Authors: Ali Saidi

import os, sys
from os.path import join as joinpath
from os import environ as env

config_path = os.path.dirname(os.path.abspath(__file__))
config_root = os.path.dirname(config_path)

def searchpath(path, filename):
    for p in path:
        f = joinpath(p, filename)
        if os.path.exists(f):
            return f
    raise IOError, "Can't find file '%s' on path." % filename

def disk(filename):
    system()
    return searchpath(disk.path, filename)

def binary(filename):
    system()
    return searchpath(binary.path, filename)

def script(filename):
    system()
    return searchpath(script.path, filename)

def system():
    if not system.path:
        try:
            path = env['M5_PATH'].split(':')
        except KeyError:
            path = [ '/dist/m5/system', '/n/poolfs/z/dist/m5/system' ]

        # expand '~' and '~user' in paths
        path = map(os.path.expanduser, path)

        # filter out non-existent directories
        system.path = filter(os.path.isdir, path)

        if not system.path:
            raise IOError, "Can't find a path to system files."

    if not binary.path:
        binary.path = [joinpath(p, 'binaries') for p in system.path]
    if not disk.path:
        disk.path = [joinpath(p, 'disks') for p in system.path]
    if not script.path:
        script.path = [joinpath(config_root, 'boot')]

system.path = None
binary.path = None
disk.path = None
script.path = None