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# ubuntuone.storageprotocol.dircontent - directory content handling
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# Author: Tim Cole <tim.cole@canonical.com>
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# Copyright 2009 Canonical Ltd.
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# This program is free software: you can redistribute it and/or modify it
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# under the terms of the GNU Affero General Public License version 3,
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# as published by the Free Software Foundation.
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranties of
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# MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
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# PURPOSE. See the GNU Affero General Public License for more details.
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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Standard routines for working with directory content.
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# DIRECTORY, FILE, and SYMLINK are for re-export
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# pylint: disable-msg=W0611
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from ubuntuone.storageprotocol.dircontent_pb2 import \
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DirectoryContent, DIRECTORY, FILE, SYMLINK
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def parse_dir_content(stream):
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"""Unserializes directory content from a stream.
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@param stream: an IO-alike stream object
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@return: a generator yielding DirEntry objects
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raw_content = stream.read()
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unserialized_content = DirectoryContent()
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# XXX: what exceptions can protobuf's parser raise?
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unserialized_content.ParseFromString(raw_content)
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for entry in unserialized_content.entries:
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yield DirEntry(name=entry.name, node_type=entry.node_type,
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def by_utf8_name(entry_a, entry_b):
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"""Compares two entries by the UTF-8 form of their names."""
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return cmp(entry_a.utf8_name, entry_b.utf8_name)
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def write_dir_content(entries, stream):
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"""Takes a sequence of DirEntry objects, sorts them, and writes
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the corresponding serialized directory content to the given stream.
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@param entries: an iterator producing DirEntry objects
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@param stream: an IO-compatible stream to write to
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sorted_entries = sorted(entries, by_utf8_name)
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for chunk in yield_presorted_dir_content(sorted_entries):
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def yield_presorted_dir_content(sorted_entries):
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"""Takes a presorted sequence of DirEntry objects and yields each
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chunks of serialized content.
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@param sorted_entries: a presorted sequence of DirEntry objects
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# A series of concatenated DirectoryContent objects is equivalent to
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# a single DirectoryContent object with fields repeated. Among other
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# things, this makes it easy to re-use the same protobuf objects for
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# each entry that we serialize.
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content = DirectoryContent()
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pb_entry = content.entries.add()
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for entry in sorted_entries:
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pb_entry.name = entry.name
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pb_entry.node_type = entry.node_type
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pb_entry.node = entry.uuid
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yield content.SerializeToString()
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class DirEntry(object):
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"""An object representing a directory entry.
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@attr name: the node's name in the directory as a unicode string
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@attr utf8_name: the node's name encoded in UTF-8
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@attr node_type: the node's type (one of FILE, DIRECTORY, or SYMLINK)
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@attr uuid: the node's server-side UUID
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def __init__(self, name=None, utf8_name=None, node_type=None, uuid=None):
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"""Initializes a directory entry object. Providing either the unicode
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or UTF-8 names will result in both name fields being set.
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@param name: the node's name in the directory
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@param utf8_name: the node's name encoded in UTF-8
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@param node_type: the node's type
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@param uuid: the node's server-sude UUID
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elif utf8_name is not None:
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self.name = utf8_name.decode("utf-8")
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if utf8_name is not None:
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self.utf8_name = utf8_name
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elif name is not None:
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self.utf8_name = name.encode("utf-8")
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self.utf8_name = None
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self.node_type = node_type
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def __eq__(self, other):
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if isinstance(other, DirEntry):
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return self.name == other.name and \
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self.utf8_name == other.utf8_name and \
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self.node_type == other.node_type and \
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self.uuid == other.uuid
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ubuntuone/storageprotocol/dircontent.py
