path: root/src/carquinyol/datastore.py

# Copyright (C) 2008, One Laptop Per Child
# Based on code Copyright (C) 2007, ObjectRealms, LLC
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

import logging
import uuid
import time
import os
import traceback

import dbus
import gobject

from sugar import mime
import sugar.datastore

from carquinyol import trace
from carquinyol import layoutmanager
from carquinyol import migration
from carquinyol.layoutmanager import MAX_QUERY_LIMIT
from carquinyol.metadatastore import MetadataStore
from carquinyol.indexstore import IndexStore
from carquinyol.filestore import FileStore
from carquinyol.optimizer import Optimizer

# the name used by the logger
DS_LOG_CHANNEL = 'org.laptop.sugar.DataStore'

DS_SERVICE = "org.laptop.sugar.DataStore"
DS_DBUS_INTERFACE = "org.laptop.sugar.DataStore"
DS_OBJECT_PATH = "/org/laptop/sugar/DataStore"

logger = logging.getLogger(DS_LOG_CHANNEL)

class DataStore(dbus.service.Object):
    """D-Bus API and logic for connecting all the other components.
    """ 
    def __init__(self, **options):
        bus_name = dbus.service.BusName(DS_SERVICE,
                                        bus=dbus.SessionBus(),
                                        replace_existing=False,
                                        allow_replacement=False)
        dbus.service.Object.__init__(self, bus_name, DS_OBJECT_PATH)

        layout_manager = layoutmanager.get_instance()
        if layout_manager.get_version() == 0:
            migration.migrate_from_0()
            layout_manager.set_version(2)
            layout_manager.index_updated = False

        if layout_manager.get_version() == 1:
            migration.migrate_from_1()
            layout_manager.set_version(2)
            layout_manager.index_updated = False

        self._metadata_store = MetadataStore()

        self._index_store = IndexStore()
        try:
            self._index_store.open_index()
        except Exception:
            logging.error('Failed to open index, will rebuild\n%s' \
                    % traceback.format_exc())
            layout_manager.index_updated = False
            self._index_store.remove_index()
            self._index_store.open_index()

        self._file_store = FileStore()

        if not layout_manager.index_updated:
            logging.debug('Index is not up-to-date, will update')
            self._rebuild_index()

        self._optimizer = Optimizer(self._file_store, self._metadata_store)

    def _rebuild_index(self):
        tvids = layoutmanager.get_instance().find_all()
        logging.debug('Going to update the index with tvids %r' % tvids)
        gobject.idle_add(lambda: self.__rebuild_index_cb(tvids),
                            priority=gobject.PRIORITY_LOW)

    def __rebuild_index_cb(self, tvids):
        if tvids:
            (tree_id,version_id) = tvids.pop()

            logging.debug('Updating entry (%r,%r) in index. %d to go.' % \
                          (tree_id, version_id, len(tvids)))

            if not self._index_store.contains(tree_id,version_id):
                try:
                    props = self._metadata_store.retrieve(tree_id,version_id)
                    self._index_store.store(tree_id, version_id, props)
                except Exception:
                    logging.error('Error processing (%r,%r)\n%s.' \
                            % (tree_id, version_id, traceback.format_exc()))

        if not tvids:
            logging.debug('Finished updating index.')
            layoutmanager.get_instance().index_updated = True
            self.Ready()
            return False
        else:
            return True

    @dbus.service.method(DS_DBUS_INTERFACE,
             in_signature='ssa{sv}sb',
             out_signature='ss',
             byte_arrays=True)
    @trace()
    def save(self, tree_id, parent_id, metadata, path, delete_after):
      return self._save(self, tree_id, parent_id, metadata, path, delete_after)

    def _save(self, tree_id, parent_id, metadata, path, delete_after):
        # TODO: copy docstring from datastore-redesign.html
        if (not tree_id) and parent_id :
            raise sugar.datastore.InvalidArgumentError("tree_id is empty but parent_id is not")

        if tree_id and not parent_id :
            if self._find({'tree_id': tree_id}, {'limit': 1})[1] :
                raise sugar.datastore.InvalidArgumentError("no parent_id given but tree_id already exists")

        elif parent_id :
            if not self._find({'tree_id': tree_id, 'version_id': parent_id}, {'limit': 1})[1] :
                raise sugar.datastore.InvalidArgumentError("given parent_id does not exist")

        if not tree_id :
            tree_id = self._gen_uuid()

        child_id = self._gen_uuid()

        # TODO: create branch if required

        metadata['ctime'] = int(time.time())
        metadata['tree_id'] = tree_id
        metadata['parent_id'] = parent_id
        metadata['version_id'] = child_id

        self._metadata_store.store(tree_id, child_id, metadata)
        # TODO: async
        self._index_store.store(tree_id, child_id, metadata)

        if (not path) and self._file_store.has_data(tree_id, parent_id) :
            # metadata-only update, reuse parent data
            path = self._file_store.retrieve(tree_id, parent_id, os.getuid(), "foo")

        if path:
            self._file_store.store(tree_id, child_id, path, delete_after,
                    lambda *args: self._save_completion_cb(tree_id, parent_id, child_id, *args))

        return (tree_id, child_id)

    @trace()
    def _save_completion_cb(self, tree_id, parent_id, child_id, exc=None):
        if exc is not None:
            logging.error("Error during saving of entry (%r,%r,%r):\n%s" % (
                tree_id, parent_id, child_id, traceback.format_exc(),))
            # FIXME: what to do on error? for the async API we already guaranteed ACID
            return

        self.Saved(tree_id, parent_id, child_id)
        self._optimizer.optimize(tree_id, child_id)
        logger.debug("updated %s %s" % (tree_id, child_id))

    @dbus.service.signal(DS_DBUS_INTERFACE, signature="sss")
    def Saved(self, tree_id, parent_id, child_id):
        # TODO: copy docstring from datastore-redesign.html
        pass

    @dbus.service.method(DS_DBUS_INTERFACE,
             in_signature='ssa{sv}',
             out_signature='',
             byte_arrays=True)
    @trace()
    def change_metadata(self, tree_id, version_id, metadata) :
        # TODO: copy docstring from datastore-redesign.html
        self._metadata_store.store(tree_id, version_id, metadata)

    @dbus.service.method(DS_DBUS_INTERFACE,
             in_signature='a{sv}a{sv}',
             out_signature='aa{sv}u')
    @trace()
    def find(self, query, options):
        return self._find(query, options)

    @dbus.service.method(DS_DBUS_INTERFACE,
             in_signature='sa{sv}a{sv}',
             out_signature='aa{sv}u')
    @trace()
    def textsearch(self, querystring, query, options) :
        return self._find(query, options, querystring)

    def _find(self, query, options, querystring = None) :
        t = time.time()

        tvids = None
        if layoutmanager.get_instance().index_updated:
            try:
                tvids, count = self._index_store.find(query, querystring, options)
            except Exception:
                logging.error('Failed to query index, will rebuild\n%s' \
                        % traceback.format_exc())
                layoutmanager.get_instance().index_updated = False
                self._index_store.close_index()
                self._index_store.remove_index()
                self._index_store.open_index()
                self._rebuild_index()

        if not layoutmanager.get_instance().index_updated:
            logging.warning('Index updating, returning all entries')

            tvids = layoutmanager.get_instance().find_all()
            if not options.get('all_versions', False) :
                # only return latest version for each entry
                tids_vtime = {}
                for (tree_id, version_id) in tvids :
                    tids_vtime.setdefault(tree_id, []).append((version_id, self._metadata_store.retrieve(tree_id, version_id, 'timestamp')))
  
                tvids = [(tree_id, sorted(candidates, key=lambda e: e[1], reverse=True)[0][0])
                         for (tree_id, candidates) in tids_vtime.items()]

            count = len(tvids)

            offset = options.get('offset', 0)
            limit = options.get('limit', MAX_QUERY_LIMIT)
            tvids = tvids[offset:offset + limit]

#        logger.debug('tvids=%r' % (tvids,))
        entries = []
        for (tree_id,version_id) in tvids:
            metadata = self._metadata_store.retrieve(tree_id, version_id, options.get('metadata'))
            entries.append(metadata)

        return entries, count

    @dbus.service.method(DS_DBUS_INTERFACE,
             in_signature='ss',
             out_signature='s',
             sender_keyword='sender')
    @trace()
    def get_data(self, tree_id, version_id, sender=None):
        # TODO: copy docstring from datastore-redesign.html
        user_id = dbus.Bus().get_unix_user(sender)
        extension = self._get_extension(tree_id, version_id)
        # TODO: async
        path = self._file_store.retrieve(tree_id, version_id, user_id, extension)
        self.GotData(sender, tree_id, version_id, path)
        return path

    @dbus.service.signal(DS_DBUS_INTERFACE, signature="ssss")
    def GotData(self, sender, tree_id, version_id, path) :
        pass

    def _get_extension(self, tree_id, version_id):
        mime_type = self._metadata_store.get_property(tree_id, version_id, 'mime_type')
        if mime_type is None or not mime_type:
            return ''
        return mime.get_primary_extension(mime_type)

    @dbus.service.method(DS_DBUS_INTERFACE,
                         in_signature='sa{sv}',
                         out_signature='as')
    def find_unique_values(self, query, metadata_name):
        # TODO: copy docstring
        # TODO: support for arbitrary metadata names and query
        if metadata_name != 'bundle_id':
            raise ValueError('Only ''bundle_id'' is a supported property name')
        if query:
            raise ValueError('The query parameter is not supported')
        if layoutmanager.get_instance().index_updated:
            return self._index_store.get_bundle_ids()
        else:
            logging.warning('Index updating, returning an empty list')
            return []

    @dbus.service.method(DS_DBUS_INTERFACE,
             in_signature='ss',
             out_signature='')
    def delete(self, tree_id, version_id):
        # TODO: version_id=None/'' => remove all versions
        self._optimizer.remove(tree_id, version_id)

        self._index_store.delete(tree_id, version_id)
        self._file_store.delete(tree_id, version_id)
        self._metadata_store.delete(tree_id, version_id)
        
        entry_path = layoutmanager.get_instance().get_entry_path(tree_id, version_id)
        os.removedirs(entry_path)

        self.Deleted(tree_id, version_id)
        logger.debug("deleted (%r,%r)" % (tree_id,version_id))

    @dbus.service.signal(DS_DBUS_INTERFACE, signature="ss")
    def Deleted(self, tree_id, version_id):
        pass

    def stop(self):
        """shutdown the service"""
        self._index_store.close_index()
        self.Stopped()

    @dbus.service.signal(DS_DBUS_INTERFACE)
    def Stopped(self):
        pass

    @dbus.service.method(DS_DBUS_INTERFACE,
             in_signature='',
             out_signature='b')
    def check_ready(self):
        return layoutmanager.get_instance().index_updated

    @dbus.service.signal(DS_DBUS_INTERFACE)
    def Ready(self):
        pass

    def _gen_uuid(self) :
      return str(uuid.uuid4())