Synnefo » Pithos

# Copyright 2011 GRNET S.A. All rights reserved.

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import os

from hashmap import HashMap

from binascii import hexlify, unhexlify

from cStringIO import StringIO

from client import Fault

def upload(client, file, container, prefix):

    meta = client.retrieve_container_metadata(container)

    blocksize = int(meta['x-container-block-size'])

    blockhash = meta['x-container-block-hash']

    size = os.path.getsize(file)

    hashes = HashMap(blocksize, blockhash)

    hashes.load(file)

    map = {'bytes': size, 'hashes': [hexlify(x) for x in hashes]}

    object = prefix + os.path.split(file)[-1]

    try:

        client.create_object_by_hashmap(container, object, map)

    except Fault, fault:

        if fault.status != 409:

            raise

    else:

        return

    missing = fault.data.split('\n')

    if '' in missing:

        del missing[missing.index(''):]

    with open(file) as fp:

        for hash in missing:

            offset = hashes.index(unhexlify(hash)) * blocksize

            fp.seek(offset)

            block = fp.read(blocksize)

            client.create_object(container, '.upload', StringIO(block))

    client.create_object_by_hashmap(container, object, map)

def download(client, container, object, file):

    meta = client.retrieve_container_metadata(container)

    blocksize = int(meta['x-container-block-size'])

    blockhash = meta['x-container-block-hash']

    if os.path.isfile(file):

        size = os.path.getsize(file)

        hashes = HashMap(blocksize, blockhash)

        hashes.load(file)

    else:

        size = 0

        hashes = []

    map = client.retrieve_object_hashmap(container, object)

    with open(file, 'a') as fp:

        for i, h in enumerate(map):

            if i < len(hashes) and h == hashes[i]:

                continue

            start = i * blocksize

            end = '' if i == len(map) - 1 else (i + 1) * blocksize

            data = client.retrieve_object(container, object, range='bytes=%s-%s' % (start, end))

            fp.seek(start)

            fp.write(data)