1 #

     2 # Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

     3 # All rights reserved.

     4 # This component and the accompanying materials are made available

     5 # under the terms of "Eclipse Public License v1.0"

     6 # which accompanies this distribution, and is available

     7 # at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 #

     9 # Initial Contributors:

    10 # Nokia Corporation - initial contribution.

    11 #

    12 # Contributors:

    13 #

    14 # Description: 

    15 #

    16 

    17 import logging

    18 import xml.parsers.expat

    19 

    20 from cone.public import api, utils

    21 from cone.storage import metadata

    22 

    23 class StorageBase(api.Storage):

    24     """

    25     A general base class for all storage type classes

    26     """

    27     METADATA_FILENAME = ".metadata"

    28 

    29     def __init__(self,path):

    30         super(StorageBase, self).__init__(path)

    31         self.meta = self.read_metadata()

    32 

    33     def get_active_configuration(self): 

    34         """

    35         Return the active configuration. 

    36         If the storage holds only one configuration, it will be always active  

    37         """

    38         root_confmls = self.list_resources("/")

    39         root_confmls = utils.resourceref.filter_resources(root_confmls,"\.confml")

    40         if self.meta.get_root_file() == '' and len(root_confmls) == 1:

    41             return root_confmls[0]

    42         else:

    43             return self.meta.get_root_file()

    44             

    45 

    46     def set_active_configuration(self, ref):

    47         self.meta.set_root_file(ref)

    48 

    49     def read_metadata(self):

    50         meta = None

    51         if not self.is_resource(self.METADATA_FILENAME):

    52             logging.getLogger('cone').info("No metadata found for: %s" % (self.get_path()))

    53             # return empty metadata object

    54             meta = metadata.Metadata()

    55         else:

    56             res = self.open_resource(self.METADATA_FILENAME)

    57             try:

    58                 try:

    59                     meta = metadata.MetadataReader().fromstring(res.read())

    60                 except xml.parsers.expat.ExpatError:

    61                     """ in case of xml parsing error return empty metadata """

    62                     meta = metadata.Metadata()

    63             finally:

    64                 res.close()

    65         return meta

    66 

    67     def write_metadata(self):

    68         # Try to update the metadata, which might fail on ZipStorage

    69 

    70         try:

    71             if self.get_mode(self.mode) != api.Storage.MODE_READ:

    72                 # update the active configuration

    73                 self.set_active_configuration(self.get_active_configuration())

    74                 metares = self.open_resource(self.METADATA_FILENAME,"wb")

    75                 metadata.MetadataWriter().toresource(self.meta,metares)

    76                 metares.close()

    77         except Exception,e:

    78             logging.getLogger('cone').error("Could not save metadata. Exception %s" % e)

    79         return

    80 

    81     def close(self):

    82         if self.get_current_path() == "": 

    83             self.write_metadata()

    84         super(StorageBase, self).close()

    85