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#!/usr/bin/env python

# Copyright (C) 2011 GRNET S.A.

#

# 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; either version 2 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; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.

"""

A tool that connects to the Pithos backend and returns the size and contents

of a pithos object.

Since the backend does not have a "root" account we use the account given in

the URL as the user when connecting to the backend.

"""

from optparse import OptionParser

from sys import exit, stdout, stderr

try:

    from pithos.backends.modular import ModularBackend

except ImportError:

    stderr.write("Pithos backend was not found.\n")

    exit(2)

parser = OptionParser(usage='%prog [options] <URL>')

parser.add_option('--db', dest='db', metavar='URI',

        help='SQLAlchemy URI of the database [REQUIRED]')

parser.add_option('--data', dest='data', metavar='DIR',

        help='path to the directory where data are stored [REQUIRED]')

parser.add_option('-s', action='store_true', dest='size', default=False,

        help='print file size and exit')

def urlsplit(url):

    """Returns (accout, container, object) from a location string"""

    assert url.startswith('pithos://'), "Invalid URL"

    t = url.split('/', 4)

    assert len(t) == 5, "Invalid URL"

    return t[2:5]

def print_size(backend, url):

    """Writes object's size to stdout."""

    account, container, object = urlsplit(url)

    meta = backend.get_object_meta(account, account, container, object, None)

    print meta['bytes']

def print_data(backend, url):

    """Writes object's size to stdout."""

    account, container, object = urlsplit(url)

    size, hashmap = backend.get_object_hashmap(account, account, container,

            object)

    for hash in hashmap:

        block = backend.get_block(hash)

        if len(block) > size:

            block = block[:size]

        stdout.write(block)

        size -= len(block)

def main():

    options, args = parser.parse_args()

    if len(args) != 1 or not options.db or not options.data:

        parser.print_help()

        exit(1)

    url = args[0]

    backend = ModularBackend(None, options.db, None, options.data)

    if options.size:

        print_size(backend, url)

    else:

        print_data(backend, url)

if __name__ == '__main__':

    main()