Synnefo

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from archipelagoblocker import ArchipelagoBlocker

class Blocker(object):

    """Blocker.

       Required constructor parameters: blocksize, blockpath, hashtype.

       Optional blockpool.

    """

    def __init__(self, **params):

        self.archip_blocker = ArchipelagoBlocker(**params)

        self.hashlen = self.archip_blocker.hashlen

        self.blocksize = params['blocksize']

    def block_hash(self, data):

        """Hash a block of data"""

        return self.archip_blocker.block_hash(data)

    def block_ping(self, hashes):

        """Check hashes for existence and

           return those missing from block storage.

        """

        return self.archip_blocker.block_ping(hashes)

    def block_retr(self, hashes):

        """Retrieve blocks from storage by their hashes."""

        return self.archip_blocker.block_retr(hashes)

    def block_retr_archipelago(self, hashes):

        """Retrieve blocks from storage by theri hashes."""

        return self.archip_blocker.block_retr_archipelago(hashes)

    def block_stor(self, blocklist):

        """Store a bunch of blocks and return (hashes, missing).

           Hashes is a list of the hashes of the blocks,

           missing is a list of indices in that list indicating

           which blocks were missing from the store.

        """

        (hashes, missing) = self.archip_blocker.block_stor(blocklist)

        return (hashes, missing)

    def block_delta(self, blkhash, offset, data):

        """Construct and store a new block from a given block

           and a data 'patch' applied at offset. Return:

           (the hash of the new block, if the block already existed)

        """

        blocksize = self.blocksize

        archip_hash = None

        archip_existed = True

        (archip_hash, archip_existed) = \

                self.archip_blocker.block_delta(blkhash, offset, data)

        if not archip_hash:

            return None, None

        if self.archip_blocker and not archip_hash:

            block = self.archip_blocker.block_retr((blkhash,))

            if not block:

                return None, None

            block = block[0]

            newblock = block[:offset] + data

            if len(newblock) > blocksize:

                newblock = newblock[:blocksize]

            elif len(newblock) < blocksize:

                newblock += block[len(newblock):]

            archip_hash, archip_existed = self.rblocker.block_stor((newblock,))

        return archip_hash, 1 if archip_existed else 0