Synnefo

# Copyright 2011-2012 GRNET S.A. All rights reserved.

#

# Redistribution and use in source and binary forms, with or

# without modification, are permitted provided that the following

# conditions are met:

#

#   1. Redistributions of source code must retain the above

#      copyright notice, this list of conditions and the following

#      disclaimer.

#

#   2. 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.

#

# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``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 GRNET S.A OR

# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

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# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED

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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN

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# The views and conclusions contained in the software and

# documentation are those of the authors and should not be

# interpreted as representing official policies, either expressed

# or implied, of GRNET S.A.

import sys

import os

import time

import uuid as uuidlib

import logging

import hashlib

import binascii

from base import DEFAULT_QUOTA, DEFAULT_VERSIONING, NotAllowedError, QuotaError, BaseBackend, \

    AccountExists, ContainerExists, AccountNotEmpty, ContainerNotEmpty, ItemNotExists, VersionNotExists

# Stripped-down version of the HashMap class found in tools.

class HashMap(list):

    def __init__(self, blocksize, blockhash):

        super(HashMap, self).__init__()

        self.blocksize = blocksize

        self.blockhash = blockhash

    def _hash_raw(self, v):

        h = hashlib.new(self.blockhash)

        h.update(v)

        return h.digest()

    def hash(self):

        if len(self) == 0:

            return self._hash_raw('')

        if len(self) == 1:

            return self.__getitem__(0)

        h = list(self)

        s = 2

        while s < len(h):

            s = s * 2

        h += [('\x00' * len(h[0]))] * (s - len(h))

        while len(h) > 1:

            h = [self._hash_raw(h[x] + h[x + 1]) for x in range(0, len(h), 2)]

        return h[0]

# Default modules and settings.

DEFAULT_DB_MODULE = 'pithos.backends.lib.sqlalchemy'

DEFAULT_DB_CONNECTION = 'sqlite:///backend.db'

DEFAULT_BLOCK_MODULE = 'pithos.backends.lib.hashfiler'

DEFAULT_BLOCK_PATH = 'data/'

DEFAULT_BLOCK_UMASK = 0o022

#DEFAULT_QUEUE_MODULE = 'pithos.backends.lib.rabbitmq'

#DEFAULT_QUEUE_CONNECTION = 'rabbitmq://guest:guest@localhost:5672/pithos'

QUEUE_MESSAGE_KEY_PREFIX = 'pithos.%s'

QUEUE_CLIENT_ID = 'pithos'

QUEUE_INSTANCE_ID = '1'

(CLUSTER_NORMAL, CLUSTER_HISTORY, CLUSTER_DELETED) = range(3)

inf = float('inf')

ULTIMATE_ANSWER = 42

logger = logging.getLogger(__name__)

def backend_method(func=None, autocommit=1):

    if func is None:

        def fn(func):

            return backend_method(func, autocommit)

        return fn

    if not autocommit:

        return func

    def fn(self, *args, **kw):

        self.wrapper.execute()

        try:

            self.messages = []

            ret = func(self, *args, **kw)

            for m in self.messages:

                self.queue.send(*m)

            self.wrapper.commit()

            return ret

        except:

            self.wrapper.rollback()

            raise

    return fn

class ModularBackend(BaseBackend):

    """A modular backend.

    Uses modules for SQL functions and storage.

    """

    def __init__(self, db_module=None, db_connection=None,

                 block_module=None, block_path=None, block_umask=None,

                 queue_module=None, queue_connection=None):

        db_module = db_module or DEFAULT_DB_MODULE

        db_connection = db_connection or DEFAULT_DB_CONNECTION

        block_module = block_module or DEFAULT_BLOCK_MODULE

        block_path = block_path or DEFAULT_BLOCK_PATH

        block_umask = block_umask or DEFAULT_BLOCK_UMASK

        #queue_module = queue_module or DEFAULT_QUEUE_MODULE

        #queue_connection = queue_connection or DEFAULT_QUEUE_CONNECTION

        self.hash_algorithm = 'sha256'

        self.block_size = 4 * 1024 * 1024  # 4MB

        self.default_policy = {'quota': DEFAULT_QUOTA,

                               'versioning': DEFAULT_VERSIONING}

        def load_module(m):

            __import__(m)

            return sys.modules[m]

        self.db_module = load_module(db_module)

        self.wrapper = self.db_module.DBWrapper(db_connection)

        params = {'wrapper': self.wrapper}

        self.permissions = self.db_module.Permissions(**params)

        for x in ['READ', 'WRITE']:

            setattr(self, x, getattr(self.db_module, x))

        self.node = self.db_module.Node(**params)

        for x in ['ROOTNODE', 'SERIAL', 'HASH', 'SIZE', 'TYPE', 'MTIME', 'MUSER', 'UUID', 'CHECKSUM', 'CLUSTER', 'MATCH_PREFIX', 'MATCH_EXACT']:

            setattr(self, x, getattr(self.db_module, x))

        self.block_module = load_module(block_module)

        params = {'path': block_path,

                  'block_size': self.block_size,

                  'hash_algorithm': self.hash_algorithm,

                  'umask': block_umask}

        self.store = self.block_module.Store(**params)

        if queue_module and queue_connection:

            self.queue_module = load_module(queue_module)

            params = {'exchange': queue_connection,

                      'client_id': QUEUE_CLIENT_ID}

            self.queue = self.queue_module.Queue(**params)

        else:

            class NoQueue:

                def send(self, *args):

                    pass

                def close(self):

                    pass

            self.queue = NoQueue()

    def close(self):

        self.wrapper.close()

        self.queue.close()

    @backend_method

    def list_accounts(self, user, marker=None, limit=10000):

        """Return a list of accounts the user can access."""

        logger.debug("list_accounts: %s %s %s", user, marker, limit)

        allowed = self._allowed_accounts(user)

        start, limit = self._list_limits(allowed, marker, limit)

        return allowed[start:start + limit]

    @backend_method

    def get_account_meta(self, user, account, domain, until=None, include_user_defined=True):

        """Return a dictionary with the account metadata for the domain."""

        logger.debug(

            "get_account_meta: %s %s %s %s", user, account, domain, until)

        path, node = self._lookup_account(account, user == account)

        if user != account:

            if until or node is None or account not in self._allowed_accounts(user):

                raise NotAllowedError

        try:

            props = self._get_properties(node, until)

            mtime = props[self.MTIME]

        except NameError:

            props = None

            mtime = until

        count, bytes, tstamp = self._get_statistics(node, until)

        tstamp = max(tstamp, mtime)

        if until is None:

            modified = tstamp

        else:

            modified = self._get_statistics(

                node)[2]  # Overall last modification.

            modified = max(modified, mtime)

        if user != account:

            meta = {'name': account}

        else:

            meta = {}

            if props is not None and include_user_defined:

                meta.update(

                    dict(self.node.attribute_get(props[self.SERIAL], domain)))

            if until is not None:

                meta.update({'until_timestamp': tstamp})

            meta.update({'name': account, 'count': count, 'bytes': bytes})

        meta.update({'modified': modified})

        return meta

    @backend_method

    def update_account_meta(self, user, account, domain, meta, replace=False):

        """Update the metadata associated with the account for the domain."""

        logger.debug("update_account_meta: %s %s %s %s %s", user,

                     account, domain, meta, replace)

        if user != account:

            raise NotAllowedError

        path, node = self._lookup_account(account, True)

        self._put_metadata(user, node, domain, meta, replace)

    @backend_method

    def get_account_groups(self, user, account):

        """Return a dictionary with the user groups defined for this account."""

        logger.debug("get_account_groups: %s %s", user, account)

        if user != account:

            if account not in self._allowed_accounts(user):

                raise NotAllowedError

            return {}

        self._lookup_account(account, True)

        return self.permissions.group_dict(account)

    @backend_method

    def update_account_groups(self, user, account, groups, replace=False):

        """Update the groups associated with the account."""

        logger.debug("update_account_groups: %s %s %s %s", user,

                     account, groups, replace)

        if user != account:

            raise NotAllowedError

        self._lookup_account(account, True)

        self._check_groups(groups)

        if replace:

            self.permissions.group_destroy(account)

        for k, v in groups.iteritems():

            if not replace:  # If not already deleted.

                self.permissions.group_delete(account, k)

            if v:

                self.permissions.group_addmany(account, k, v)

    @backend_method

    def get_account_policy(self, user, account):

        """Return a dictionary with the account policy."""

        logger.debug("get_account_policy: %s %s", user, account)

        if user != account:

            if account not in self._allowed_accounts(user):

                raise NotAllowedError

            return {}

        path, node = self._lookup_account(account, True)

        return self._get_policy(node)

    @backend_method

    def update_account_policy(self, user, account, policy, replace=False):

        """Update the policy associated with the account."""

        logger.debug("update_account_policy: %s %s %s %s", user,

                     account, policy, replace)

        if user != account:

            raise NotAllowedError

        path, node = self._lookup_account(account, True)

        self._check_policy(policy)

        self._put_policy(node, policy, replace)

    @backend_method

    def put_account(self, user, account, policy={}):

        """Create a new account with the given name."""

        logger.debug("put_account: %s %s %s", user, account, policy)

        if user != account:

            raise NotAllowedError

        node = self.node.node_lookup(account)

        if node is not None:

            raise AccountExists('Account already exists')

        if policy:

            self._check_policy(policy)

        node = self._put_path(user, self.ROOTNODE, account)

        self._put_policy(node, policy, True)

    @backend_method

    def delete_account(self, user, account):

        """Delete the account with the given name."""

        logger.debug("delete_account: %s %s", user, account)

        if user != account:

            raise NotAllowedError

        node = self.node.node_lookup(account)

        if node is None:

            return

        if not self.node.node_remove(node):

            raise AccountNotEmpty('Account is not empty')

        self.permissions.group_destroy(account)

    @backend_method

    def list_containers(self, user, account, marker=None, limit=10000, shared=False, until=None, public=False):

        """Return a list of containers existing under an account."""

        logger.debug("list_containers: %s %s %s %s %s %s %s", user,

                     account, marker, limit, shared, until, public)

        if user != account:

            if until or account not in self._allowed_accounts(user):

                raise NotAllowedError

            allowed = self._allowed_containers(user, account)

            start, limit = self._list_limits(allowed, marker, limit)

            return allowed[start:start + limit]

        if shared or public:

            allowed = set()

            if shared:

                allowed.update([x.split('/', 2)[1] for x in self.permissions.access_list_shared(account)])

            if public:

                allowed.update([x[0].split('/', 2)[1] for x in self.permissions.public_list(account)])

            allowed = sorted(allowed)

            start, limit = self._list_limits(allowed, marker, limit)

            return allowed[start:start + limit]

        node = self.node.node_lookup(account)

        containers = [x[0] for x in self._list_object_properties(

            node, account, '', '/', marker, limit, False, None, [], until)]

        start, limit = self._list_limits(

            [x[0] for x in containers], marker, limit)

        return containers[start:start + limit]

    @backend_method

    def list_container_meta(self, user, account, container, domain, until=None):

        """Return a list with all the container's object meta keys for the domain."""

        logger.debug("list_container_meta: %s %s %s %s %s", user,

                     account, container, domain, until)

        allowed = []

        if user != account:

            if until:

                raise NotAllowedError

            allowed = self.permissions.access_list_paths(

                user, '/'.join((account, container)))

            if not allowed:

                raise NotAllowedError

        path, node = self._lookup_container(account, container)

        before = until if until is not None else inf

        allowed = self._get_formatted_paths(allowed)

        return self.node.latest_attribute_keys(node, domain, before, CLUSTER_DELETED, allowed)

    @backend_method

    def get_container_meta(self, user, account, container, domain, until=None, include_user_defined=True):

        """Return a dictionary with the container metadata for the domain."""

        logger.debug("get_container_meta: %s %s %s %s %s", user,

                     account, container, domain, until)

        if user != account:

            if until or container not in self._allowed_containers(user, account):

                raise NotAllowedError

        path, node = self._lookup_container(account, container)

        props = self._get_properties(node, until)

        mtime = props[self.MTIME]

        count, bytes, tstamp = self._get_statistics(node, until)

        tstamp = max(tstamp, mtime)

        if until is None:

            modified = tstamp

        else:

            modified = self._get_statistics(

                node)[2]  # Overall last modification.

            modified = max(modified, mtime)

        if user != account:

            meta = {'name': container}

        else:

            meta = {}

            if include_user_defined:

                meta.update(

                    dict(self.node.attribute_get(props[self.SERIAL], domain)))

            if until is not None:

                meta.update({'until_timestamp': tstamp})

            meta.update({'name': container, 'count': count, 'bytes': bytes})

        meta.update({'modified': modified})

        return meta

    @backend_method

    def update_container_meta(self, user, account, container, domain, meta, replace=False):

        """Update the metadata associated with the container for the domain."""

        logger.debug("update_container_meta: %s %s %s %s %s %s",

                     user, account, container, domain, meta, replace)

        if user != account:

            raise NotAllowedError

        path, node = self._lookup_container(account, container)

        src_version_id, dest_version_id = self._put_metadata(

            user, node, domain, meta, replace)

        if src_version_id is not None:

            versioning = self._get_policy(node)['versioning']

            if versioning != 'auto':

                self.node.version_remove(src_version_id)

    @backend_method

    def get_container_policy(self, user, account, container):

        """Return a dictionary with the container policy."""

        logger.debug(

            "get_container_policy: %s %s %s", user, account, container)

        if user != account:

            if container not in self._allowed_containers(user, account):

                raise NotAllowedError

            return {}

        path, node = self._lookup_container(account, container)

        return self._get_policy(node)

    @backend_method

    def update_container_policy(self, user, account, container, policy, replace=False):

        """Update the policy associated with the container."""

        logger.debug("update_container_policy: %s %s %s %s %s",

                     user, account, container, policy, replace)

        if user != account:

            raise NotAllowedError

        path, node = self._lookup_container(account, container)

        self._check_policy(policy)

        self._put_policy(node, policy, replace)

    @backend_method

    def put_container(self, user, account, container, policy={}):

        """Create a new container with the given name."""

        logger.debug(

            "put_container: %s %s %s %s", user, account, container, policy)

        if user != account:

            raise NotAllowedError

        try:

            path, node = self._lookup_container(account, container)

        except NameError:

            pass

        else:

            raise ContainerExists('Container already exists')

        if policy:

            self._check_policy(policy)

        path = '/'.join((account, container))

        node = self._put_path(

            user, self._lookup_account(account, True)[1], path)

        self._put_policy(node, policy, True)

    @backend_method

    def delete_container(self, user, account, container, until=None, prefix='', delimiter=None):

        """Delete/purge the container with the given name."""

        logger.debug("delete_container: %s %s %s %s %s %s", user,

                     account, container, until, prefix, delimiter)

        if user != account:

            raise NotAllowedError

        path, node = self._lookup_container(account, container)

        if until is not None:

            hashes, size = self.node.node_purge_children(

                node, until, CLUSTER_HISTORY)

            for h in hashes:

                self.store.map_delete(h)

            self.node.node_purge_children(node, until, CLUSTER_DELETED)

            self._report_size_change(user, account, -size, {'action':

                                     'container purge', 'path': path})

            return

        if not delimiter:

            if self._get_statistics(node)[0] > 0:

                raise ContainerNotEmpty('Container is not empty')

            hashes, size = self.node.node_purge_children(

                node, inf, CLUSTER_HISTORY)

            for h in hashes:

                self.store.map_delete(h)

            self.node.node_purge_children(node, inf, CLUSTER_DELETED)

            self.node.node_remove(node)

            self._report_size_change(user, account, -size, {'action':

                                     'container delete', 'path': path})

        else:

                # remove only contents

            src_names = self._list_objects_no_limit(user, account, container, prefix='', delimiter=None, virtual=False, domain=None, keys=[], shared=False, until=None, size_range=None, all_props=True, public=False)

            paths = []

            for t in src_names:

                path = '/'.join((account, container, t[0]))

                node = t[2]

                src_version_id, dest_version_id = self._put_version_duplicate(user, node, size=0, type='', hash=None, checksum='', cluster=CLUSTER_DELETED)

                del_size = self._apply_versioning(

                    account, container, src_version_id)

                if del_size:

                    self._report_size_change(user, account, -del_size, {'action': 'object delete', 'path': path})

                self._report_object_change(

                    user, account, path, details={'action': 'object delete'})

                paths.append(path)

            self.permissions.access_clear_bulk(paths)

    def _list_objects(self, user, account, container, prefix, delimiter, marker, limit, virtual, domain, keys, shared, until, size_range, all_props, public):

        if user != account and until:

            raise NotAllowedError

        if shared and public:

            # get shared first

            shared = self._list_object_permissions(

                user, account, container, prefix, shared=True, public=False)

            objects = set()

            if shared:

                path, node = self._lookup_container(account, container)

                shared = self._get_formatted_paths(shared)

                objects |= set(self._list_object_properties(node, path, prefix, delimiter, marker, limit, virtual, domain, keys, until, size_range, shared, all_props))

            # get public

            objects |= set(self._list_public_object_properties(

                user, account, container, prefix, all_props))

            objects = list(objects)

            objects.sort(key=lambda x: x[0])

            start, limit = self._list_limits(

                [x[0] for x in objects], marker, limit)

            return objects[start:start + limit]

        elif public:

            objects = self._list_public_object_properties(

                user, account, container, prefix, all_props)

            start, limit = self._list_limits(

                [x[0] for x in objects], marker, limit)

            return objects[start:start + limit]

        allowed = self._list_object_permissions(

            user, account, container, prefix, shared, public)

        if shared and not allowed:

            return []

        path, node = self._lookup_container(account, container)

        allowed = self._get_formatted_paths(allowed)

        objects = self._list_object_properties(node, path, prefix, delimiter, marker, limit, virtual, domain, keys, until, size_range, allowed, all_props)

        start, limit = self._list_limits(

            [x[0] for x in objects], marker, limit)

        return objects[start:start + limit]

    def _list_public_object_properties(self, user, account, container, prefix, all_props):

        public = self._list_object_permissions(

            user, account, container, prefix, shared=False, public=True)

        paths, nodes = self._lookup_objects(public)

        path = '/'.join((account, container))

        cont_prefix = path + '/'

        paths = [x[len(cont_prefix):] for x in paths]

        props = self.node.version_lookup_bulk(nodes, all_props=all_props)

        objects = [(path,) + props for path, props in zip(paths, props)]

        return objects

    def _list_objects_no_limit(self, user, account, container, prefix, delimiter, virtual, domain, keys, shared, until, size_range, all_props, public):

        objects = []

        while True:

            marker = objects[-1] if objects else None

            limit = 10000

            l = self._list_objects(user, account, container, prefix, delimiter, marker, limit, virtual, domain, keys, shared, until, size_range, all_props, public)

            objects.extend(l)

            if not l or len(l) < limit:

                break

        return objects

    def _list_object_permissions(self, user, account, container, prefix, shared, public):

        allowed = []

        path = '/'.join((account, container, prefix)).rstrip('/')

        if user != account:

            allowed = self.permissions.access_list_paths(user, path)

            if not allowed:

                raise NotAllowedError

        else:

            allowed = set()

            if shared:

                allowed.update(self.permissions.access_list_shared(path))

            if public:

                allowed.update(

                    [x[0] for x in self.permissions.public_list(path)])

            allowed = sorted(allowed)

            if not allowed:

                return []

        return allowed

    @backend_method

    def list_objects(self, user, account, container, prefix='', delimiter=None, marker=None, limit=10000, virtual=True, domain=None, keys=[], shared=False, until=None, size_range=None, public=False):

        """Return a list of object (name, version_id) tuples existing under a container."""

        logger.debug("list_objects: %s %s %s %s %s %s %s %s %s %s %s %s %s %s", user, account, container, prefix, delimiter, marker, limit, virtual, domain, keys, shared, until, size_range, public)

        return self._list_objects(user, account, container, prefix, delimiter, marker, limit, virtual, domain, keys, shared, until, size_range, False, public)

    @backend_method

    def list_object_meta(self, user, account, container, prefix='', delimiter=None, marker=None, limit=10000, virtual=True, domain=None, keys=[], shared=False, until=None, size_range=None, public=False):

        """Return a list of object metadata dicts existing under a container."""

        logger.debug("list_object_meta: %s %s %s %s %s %s %s %s %s %s %s %s %s %s", user, account, container, prefix, delimiter, marker, limit, virtual, domain, keys, shared, until, size_range, public)

        props = self._list_objects(user, account, container, prefix, delimiter, marker, limit, virtual, domain, keys, shared, until, size_range, True, public)

        objects = []

        for p in props:

            if len(p) == 2:

                objects.append({'subdir': p[0]})

            else:

                objects.append({'name': p[0],

                                'bytes': p[self.SIZE + 1],

                                'type': p[self.TYPE + 1],

                                'hash': p[self.HASH + 1],

                                'version': p[self.SERIAL + 1],

                                'version_timestamp': p[self.MTIME + 1],

                                'modified': p[self.MTIME + 1] if until is None else None,

                                'modified_by': p[self.MUSER + 1],

                                'uuid': p[self.UUID + 1],

                                'checksum': p[self.CHECKSUM + 1]})

        return objects

    @backend_method

    def list_object_permissions(self, user, account, container, prefix=''):

        """Return a list of paths that enforce permissions under a container."""

        logger.debug("list_object_permissions: %s %s %s %s", user,

                     account, container, prefix)

        return self._list_object_permissions(user, account, container, prefix, True, False)

    @backend_method

    def list_object_public(self, user, account, container, prefix=''):

        """Return a dict mapping paths to public ids for objects that are public under a container."""

        logger.debug("list_object_public: %s %s %s %s", user,

                     account, container, prefix)

        public = {}

        for path, p in self.permissions.public_list('/'.join((account, container, prefix))):

            public[path] = p + ULTIMATE_ANSWER

        return public

    @backend_method

    def get_object_meta(self, user, account, container, name, domain, version=None, include_user_defined=True):

        """Return a dictionary with the object metadata for the domain."""

        logger.debug("get_object_meta: %s %s %s %s %s %s", user,

                     account, container, name, domain, version)

        self._can_read(user, account, container, name)

        path, node = self._lookup_object(account, container, name)

        props = self._get_version(node, version)

        if version is None:

            modified = props[self.MTIME]

        else:

            try:

                modified = self._get_version(

                    node)[self.MTIME]  # Overall last modification.

            except NameError:  # Object may be deleted.

                del_props = self.node.version_lookup(

                    node, inf, CLUSTER_DELETED)

                if del_props is None:

                    raise ItemNotExists('Object does not exist')

                modified = del_props[self.MTIME]

        meta = {}

        if include_user_defined:

            meta.update(

                dict(self.node.attribute_get(props[self.SERIAL], domain)))

        meta.update({'name': name,

                     'bytes': props[self.SIZE],

                     'type': props[self.TYPE],

                     'hash': props[self.HASH],

                     'version': props[self.SERIAL],

                     'version_timestamp': props[self.MTIME],

                     'modified': modified,

                     'modified_by': props[self.MUSER],

                     'uuid': props[self.UUID],

                     'checksum': props[self.CHECKSUM]})

        return meta

    @backend_method

    def update_object_meta(self, user, account, container, name, domain, meta, replace=False):

        """Update the metadata associated with the object for the domain and return the new version."""

        logger.debug("update_object_meta: %s %s %s %s %s %s %s",

                     user, account, container, name, domain, meta, replace)

        self._can_write(user, account, container, name)

        path, node = self._lookup_object(account, container, name)

        src_version_id, dest_version_id = self._put_metadata(

            user, node, domain, meta, replace)

        self._apply_versioning(account, container, src_version_id)

        return dest_version_id

    @backend_method

    def get_object_permissions(self, user, account, container, name):

        """Return the action allowed on the object, the path

        from which the object gets its permissions from,

        along with a dictionary containing the permissions."""

        logger.debug("get_object_permissions: %s %s %s %s", user,

                     account, container, name)

        allowed = 'write'

        permissions_path = self._get_permissions_path(account, container, name)

        if user != account:

            if self.permissions.access_check(permissions_path, self.WRITE, user):

                allowed = 'write'

            elif self.permissions.access_check(permissions_path, self.READ, user):

                allowed = 'read'

            else:

                raise NotAllowedError

        self._lookup_object(account, container, name)

        return (allowed, permissions_path, self.permissions.access_get(permissions_path))

    @backend_method

    def update_object_permissions(self, user, account, container, name, permissions):

        """Update the permissions associated with the object."""

        logger.debug("update_object_permissions: %s %s %s %s %s",

                     user, account, container, name, permissions)

        if user != account:

            raise NotAllowedError

        path = self._lookup_object(account, container, name)[0]

        self._check_permissions(path, permissions)

        self.permissions.access_set(path, permissions)

        self._report_sharing_change(user, account, path, {'members':

                                    self.permissions.access_members(path)})

    @backend_method

    def get_object_public(self, user, account, container, name):

        """Return the public id of the object if applicable."""

        logger.debug(

            "get_object_public: %s %s %s %s", user, account, container, name)

        self._can_read(user, account, container, name)

        path = self._lookup_object(account, container, name)[0]

        p = self.permissions.public_get(path)

        if p is not None:

            p += ULTIMATE_ANSWER

        return p

    @backend_method

    def update_object_public(self, user, account, container, name, public):

        """Update the public status of the object."""

        logger.debug("update_object_public: %s %s %s %s %s", user,

                     account, container, name, public)

        self._can_write(user, account, container, name)

        path = self._lookup_object(account, container, name)[0]

        if not public:

            self.permissions.public_unset(path)

        else:

            self.permissions.public_set(path)

    @backend_method

    def get_object_hashmap(self, user, account, container, name, version=None):

        """Return the object's size and a list with partial hashes."""

        logger.debug("get_object_hashmap: %s %s %s %s %s", user,

                     account, container, name, version)

        self._can_read(user, account, container, name)

        path, node = self._lookup_object(account, container, name)

        props = self._get_version(node, version)

        hashmap = self.store.map_get(binascii.unhexlify(props[self.HASH]))

        return props[self.SIZE], [binascii.hexlify(x) for x in hashmap]

    def _update_object_hash(self, user, account, container, name, size, type, hash, checksum, domain, meta, replace_meta, permissions, src_node=None, src_version_id=None, is_copy=False):

        if permissions is not None and user != account:

            raise NotAllowedError

        self._can_write(user, account, container, name)

        if permissions is not None:

            path = '/'.join((account, container, name))

            self._check_permissions(path, permissions)

        account_path, account_node = self._lookup_account(account, True)

        container_path, container_node = self._lookup_container(

            account, container)

        path, node = self._put_object_node(

            container_path, container_node, name)

        pre_version_id, dest_version_id = self._put_version_duplicate(user, node, src_node=src_node, size=size, type=type, hash=hash, checksum=checksum, is_copy=is_copy)

        # Handle meta.

        if src_version_id is None:

            src_version_id = pre_version_id

        self._put_metadata_duplicate(

            src_version_id, dest_version_id, domain, meta, replace_meta)

        # Check quota.

        del_size = self._apply_versioning(account, container, pre_version_id)

        size_delta = size - del_size

        if size_delta > 0:

            account_quota = long(self._get_policy(account_node)['quota'])

            container_quota = long(self._get_policy(container_node)['quota'])

            if (account_quota > 0 and self._get_statistics(account_node)[1] + size_delta > account_quota) or \

               (container_quota > 0 and self._get_statistics(container_node)[1] + size_delta > container_quota):

                # This must be executed in a transaction, so the version is never created if it fails.

                raise QuotaError

        self._report_size_change(user, account, size_delta, {

                                 'action': 'object update', 'path': path})

        if permissions is not None:

            self.permissions.access_set(path, permissions)

            self._report_sharing_change(user, account, path, {'members': self.permissions.access_members(path)})

        self._report_object_change(user, account, path, details={'version': dest_version_id, 'action': 'object update'})

        return dest_version_id

    @backend_method

    def update_object_hashmap(self, user, account, container, name, size, type, hashmap, checksum, domain, meta={}, replace_meta=False, permissions=None):

        """Create/update an object with the specified size and partial hashes."""

        logger.debug("update_object_hashmap: %s %s %s %s %s %s %s %s", user,

                     account, container, name, size, type, hashmap, checksum)

        if size == 0:  # No such thing as an empty hashmap.

            hashmap = [self.put_block('')]

        map = HashMap(self.block_size, self.hash_algorithm)

        map.extend([binascii.unhexlify(x) for x in hashmap])

        missing = self.store.block_search(map)

        if missing:

            ie = IndexError()

            ie.data = [binascii.hexlify(x) for x in missing]

            raise ie

        hash = map.hash()

        dest_version_id = self._update_object_hash(user, account, container, name, size, type, binascii.hexlify(hash), checksum, domain, meta, replace_meta, permissions)

        self.store.map_put(hash, map)

        return dest_version_id

    @backend_method

    def update_object_checksum(self, user, account, container, name, version, checksum):

        """Update an object's checksum."""

        logger.debug("update_object_checksum: %s %s %s %s %s %s",

                     user, account, container, name, version, checksum)

        # Update objects with greater version and same hashmap and size (fix metadata updates).

        self._can_write(user, account, container, name)

        path, node = self._lookup_object(account, container, name)

        props = self._get_version(node, version)

        versions = self.node.node_get_versions(node)

        for x in versions:

            if x[self.SERIAL] >= int(version) and x[self.HASH] == props[self.HASH] and x[self.SIZE] == props[self.SIZE]:

                self.node.version_put_property(

                    x[self.SERIAL], 'checksum', checksum)

    def _copy_object(self, user, src_account, src_container, src_name, dest_account, dest_container, dest_name, type, dest_domain=None, dest_meta={}, replace_meta=False, permissions=None, src_version=None, is_move=False, delimiter=None):

        dest_version_ids = []

        self._can_read(user, src_account, src_container, src_name)

        path, node = self._lookup_object(src_account, src_container, src_name)

        # TODO: Will do another fetch of the properties in duplicate version...

        props = self._get_version(

            node, src_version)  # Check to see if source exists.

        src_version_id = props[self.SERIAL]

        hash = props[self.HASH]

        size = props[self.SIZE]

        is_copy = not is_move and (src_account, src_container, src_name) != (

            dest_account, dest_container, dest_name)  # New uuid.

        dest_version_ids.append(self._update_object_hash(user, dest_account, dest_container, dest_name, size, type, hash, None, dest_domain, dest_meta, replace_meta, permissions, src_node=node, src_version_id=src_version_id, is_copy=is_copy))

        if is_move and (src_account, src_container, src_name) != (dest_account, dest_container, dest_name):

            self._delete_object(user, src_account, src_container, src_name)

        if delimiter:

            prefix = src_name + \

                delimiter if not src_name.endswith(delimiter) else src_name

            src_names = self._list_objects_no_limit(user, src_account, src_container, prefix, delimiter=None, virtual=False, domain=None, keys=[], shared=False, until=None, size_range=None, all_props=True, public=False)

            src_names.sort(key=lambda x: x[2])  # order by nodes

            paths = [elem[0] for elem in src_names]

            nodes = [elem[2] for elem in src_names]

            # TODO: Will do another fetch of the properties in duplicate version...

            props = self._get_versions(nodes)  # Check to see if source exists.

            for prop, path, node in zip(props, paths, nodes):

                src_version_id = prop[self.SERIAL]

                hash = prop[self.HASH]

                vtype = prop[self.TYPE]

                size = prop[self.SIZE]

                dest_prefix = dest_name + delimiter if not dest_name.endswith(

                    delimiter) else dest_name

                vdest_name = path.replace(prefix, dest_prefix, 1)

                dest_version_ids.append(self._update_object_hash(user, dest_account, dest_container, vdest_name, size, vtype, hash, None, dest_domain, meta={}, replace_meta=False, permissions=None, src_node=node, src_version_id=src_version_id, is_copy=is_copy))

                if is_move and (src_account, src_container, src_name) != (dest_account, dest_container, dest_name):

                    self._delete_object(user, src_account, src_container, path)

        return dest_version_ids[0] if len(dest_version_ids) == 1 else dest_version_ids

    @backend_method

    def copy_object(self, user, src_account, src_container, src_name, dest_account, dest_container, dest_name, type, domain, meta={}, replace_meta=False, permissions=None, src_version=None, delimiter=None):

        """Copy an object's data and metadata."""

        logger.debug("copy_object: %s %s %s %s %s %s %s %s %s %s %s %s %s %s", user, src_account, src_container, src_name, dest_account, dest_container, dest_name, type, domain, meta, replace_meta, permissions, src_version, delimiter)

        dest_version_id = self._copy_object(user, src_account, src_container, src_name, dest_account, dest_container, dest_name, type, domain, meta, replace_meta, permissions, src_version, False, delimiter)

        return dest_version_id

    @backend_method

    def move_object(self, user, src_account, src_container, src_name, dest_account, dest_container, dest_name, type, domain, meta={}, replace_meta=False, permissions=None, delimiter=None):

        """Move an object's data and metadata."""

        logger.debug("move_object: %s %s %s %s %s %s %s %s %s %s %s %s %s", user, src_account, src_container, src_name, dest_account, dest_container, dest_name, type, domain, meta, replace_meta, permissions, delimiter)

        if user != src_account:

            raise NotAllowedError

        dest_version_id = self._copy_object(user, src_account, src_container, src_name, dest_account, dest_container, dest_name, type, domain, meta, replace_meta, permissions, None, True, delimiter)

        return dest_version_id

    def _delete_object(self, user, account, container, name, until=None, delimiter=None):

        if user != account:

            raise NotAllowedError

        if until is not None:

            path = '/'.join((account, container, name))

            node = self.node.node_lookup(path)

            if node is None:

                return

            hashes = []

            size = 0

            h, s = self.node.node_purge(node, until, CLUSTER_NORMAL)

            hashes += h

            size += s

            h, s = self.node.node_purge(node, until, CLUSTER_HISTORY)

            hashes += h

            size += s

            for h in hashes:

                self.store.map_delete(h)

            self.node.node_purge(node, until, CLUSTER_DELETED)

            try:

                props = self._get_version(node)

            except NameError:

                self.permissions.access_clear(path)

            self._report_size_change(user, account, -size, {

                                     'action': 'object purge', 'path': path})

            return

        path, node = self._lookup_object(account, container, name)

        src_version_id, dest_version_id = self._put_version_duplicate(user, node, size=0, type='', hash=None, checksum='', cluster=CLUSTER_DELETED)

        del_size = self._apply_versioning(account, container, src_version_id)

        if del_size:

            self._report_size_change(user, account, -del_size, {

                                     'action': 'object delete', 'path': path})

        self._report_object_change(

            user, account, path, details={'action': 'object delete'})

        self.permissions.access_clear(path)

        if delimiter:

            prefix = name + delimiter if not name.endswith(delimiter) else name

            src_names = self._list_objects_no_limit(user, account, container, prefix, delimiter=None, virtual=False, domain=None, keys=[], shared=False, until=None, size_range=None, all_props=True, public=False)

            paths = []

            for t in src_names:

                path = '/'.join((account, container, t[0]))

                node = t[2]

                src_version_id, dest_version_id = self._put_version_duplicate(user, node, size=0, type='', hash=None, checksum='', cluster=CLUSTER_DELETED)

                del_size = self._apply_versioning(

                    account, container, src_version_id)

                if del_size:

                    self._report_size_change(user, account, -del_size, {'action': 'object delete', 'path': path})

                self._report_object_change(

                    user, account, path, details={'action': 'object delete'})

                paths.append(path)

            self.permissions.access_clear_bulk(paths)

    @backend_method

    def delete_object(self, user, account, container, name, until=None, prefix='', delimiter=None):

        """Delete/purge an object."""

        logger.debug("delete_object: %s %s %s %s %s %s %s", user,

                     account, container, name, until, prefix, delimiter)

        self._delete_object(user, account, container, name, until, delimiter)

    @backend_method

    def list_versions(self, user, account, container, name):

        """Return a list of all (version, version_timestamp) tuples for an object."""

        logger.debug(

            "list_versions: %s %s %s %s", user, account, container, name)

        self._can_read(user, account, container, name)

        path, node = self._lookup_object(account, container, name)

        versions = self.node.node_get_versions(node)

        return [[x[self.SERIAL], x[self.MTIME]] for x in versions if x[self.CLUSTER] != CLUSTER_DELETED]

    @backend_method

    def get_uuid(self, user, uuid):

        """Return the (account, container, name) for the UUID given."""

        logger.debug("get_uuid: %s %s", user, uuid)

        info = self.node.latest_uuid(uuid)

        if info is None:

            raise NameError

        path, serial = info

        account, container, name = path.split('/', 2)

        self._can_read(user, account, container, name)

        return (account, container, name)

    @backend_method

    def get_public(self, user, public):

        """Return the (account, container, name) for the public id given."""

        logger.debug("get_public: %s %s", user, public)

        if public is None or public < ULTIMATE_ANSWER:

            raise NameError

        path = self.permissions.public_path(public - ULTIMATE_ANSWER)

        if path is None:

            raise NameError

        account, container, name = path.split('/', 2)

        self._can_read(user, account, container, name)

        return (account, container, name)

    @backend_method(autocommit=0)

    def get_block(self, hash):

        """Return a block's data."""

        logger.debug("get_block: %s", hash)

        block = self.store.block_get(binascii.unhexlify(hash))

        if not block:

            raise ItemNotExists('Block does not exist')

        return block

    @backend_method(autocommit=0)

    def put_block(self, data):

        """Store a block and return the hash."""

        logger.debug("put_block: %s", len(data))

        return binascii.hexlify(self.store.block_put(data))

    @backend_method(autocommit=0)

    def update_block(self, hash, data, offset=0):

        """Update a known block and return the hash."""

        logger.debug("update_block: %s %s %s", hash, len(data), offset)

        if offset == 0 and len(data) == self.block_size:

            return self.put_block(data)

        h = self.store.block_update(binascii.unhexlify(hash), offset, data)

        return binascii.hexlify(h)

    # Path functions.

    def _generate_uuid(self):

        return str(uuidlib.uuid4())

    def _put_object_node(self, path, parent, name):

        path = '/'.join((path, name))

        node = self.node.node_lookup(path)

        if node is None:

            node = self.node.node_create(parent, path)

        return path, node

    def _put_path(self, user, parent, path):

        node = self.node.node_create(parent, path)

        self.node.version_create(node, None, 0, '', None, user,

                                 self._generate_uuid(), '', CLUSTER_NORMAL)

        return node

    def _lookup_account(self, account, create=True):

        node = self.node.node_lookup(account)

        if node is None and create:

            node = self._put_path(

                account, self.ROOTNODE, account)  # User is account.

        return account, node

    def _lookup_container(self, account, container):

        path = '/'.join((account, container))

        node = self.node.node_lookup(path)

        if node is None:

            raise ItemNotExists('Container does not exist')

        return path, node

    def _lookup_object(self, account, container, name):

        path = '/'.join((account, container, name))

        node = self.node.node_lookup(path)

        if node is None:

            raise ItemNotExists('Object does not exist')

        return path, node

    def _lookup_objects(self, paths):

        nodes = self.node.node_lookup_bulk(paths)