/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/session.py
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revision 197 by jan, Thu Jun 20 15:20:58 2002 UTC revision 982 by bh, Thu May 22 12:02:15 2003 UTC
# Line 1  Line 1 
1  # Copyright (c) 2001, 2002 by Intevation GmbH  # Copyright (c) 2001, 2002, 2003 by Intevation GmbH
2  # Authors:  # Authors:
3  # Bernhard Herzog <[email protected]>  # Bernhard Herzog <[email protected]>
4  # Jan-Oliver Wagner <[email protected]>  # Jan-Oliver Wagner <[email protected]>
# Line 8  Line 8 
8    
9  __version__ = "$Revision$"  __version__ = "$Revision$"
10    
11  from Thuban.Lib.connector import Publisher  import os
12    from tempfile import mktemp
13    import weakref
14    
15  from messages import MAPS_CHANGED, EXTENSIONS_CHANGED, FILENAME_CHANGED, \  from messages import MAPS_CHANGED, EXTENSIONS_CHANGED, FILENAME_CHANGED, \
16       LAYERS_CHANGED, MAP_PROJECTION_CHANGED, \       MAP_LAYERS_CHANGED, MAP_PROJECTION_CHANGED, \
17       LAYER_LEGEND_CHANGED, LAYER_PROJECTION_CHANGED, LAYER_VISIBILITY_CHANGED, \       LAYER_CHANGED, LAYER_PROJECTION_CHANGED, LAYER_VISIBILITY_CHANGED,\
18       EXTENSION_CHANGED, EXTENSION_OBJECTS_CHANGED       EXTENSION_CHANGED, EXTENSION_OBJECTS_CHANGED, CHANGED
19    
20  from base import TitledObject, Modifiable  from Thuban import _
21    
22    from base import TitledObject, Modifiable
23  from map import Map  from map import Map
24    from data import ShapefileStore
25    
26    from transientdb import TransientDatabase, AutoTransientTable
27    
28    class AutoRemoveFile:
29    
30        """Remove a file once all references go away."""
31    
32        def __init__(self, filename, tempdir = None):
33            """Initialize the AutoRemoveFile
34    
35            Parameters:
36               filename -- The name of the file to remove in __del__
37               tempdir -- Another object simple stored as an instance variable.
38    
39            As the name suggests the tempdir parameter is intended for a
40            temporary directory the file might be located in. The intended
41            use is that it's an instance of AutoRemoveDir.
42            """
43            self.filename = filename
44            self.tempdir = tempdir
45    
46        def __del__(self, remove = os.remove):
47            remove(self.filename)
48    
49    class AutoRemoveDir:
50    
51        """Remove a directory once all references go away
52    
53        The intended use of this class together with AutoRemoveFile is for
54        temporary directories and files containd therein. An AutoRemoveDir
55        should be instantiated for the directory and passed as the tempdir
56        parameter to every AutoRemoveFile instance created for files in the
57        directory. An AutoRemoveFile shold be instantiated for every file
58        created in the directory so that the directory is automatically
59        removed once the last file is removed.
60        """
61    
62        def __init__(self, filename):
63            """Initialize the AutoRemoveDir
64    
65            The parameter is the name of the directory.
66            """
67            self.filename = filename
68    
69        def __del__(self, rmdir = os.rmdir):
70            rmdir(self.filename)
71    
72    
73    # WeakKey dictionary mapping objects like the transient_db to
74    # AutoRemoveDir or AutoRemoveFile instances to make sure that the
75    # temporary files and the directory are deleted but not before the
76    # objects that use them go away.
77    auto_remover = weakref.WeakKeyDictionary()
78    
79  class Session(TitledObject, Modifiable):  class Session(TitledObject, Modifiable):
80    
81      """A complete session.      """A complete session.
# Line 36  class Session(TitledObject, Modifiable): Line 92  class Session(TitledObject, Modifiable):
92    
93          EXTENSIONS_CHANGED -- Extensions were added, removed.          EXTENSIONS_CHANGED -- Extensions were added, removed.
94    
95          LAYERS_CHANGED -- Same as the map's event of the same name.          MAP_LAYERS_CHANGED -- Same as the map's event of the same name.
96                            It's simply resent from the session to make                            It's simply resent from the session to make
97                            subscriptions easier.                            subscriptions easier.
98    
99            CHANGED -- Generic changed event. Parameters: the session. The
100                       event is always issued when any other changed event
101                       is issused. This is useful for code that needs to be
102                       notified whenever something in the session has
103                       changed but it's too cumbersome or error-prone to
104                       subscribe to all the individual events.
105      """      """
106    
107      # message channels that have to be forwarded from maps contained in      # message channels that have to be forwarded from maps contained in
108      # the session.      # the session.
109      forwarded_channels = (      forwarded_channels = (
110            # generic channels
111            CHANGED,
112    
113          # map specific channels          # map specific channels
114          MAP_PROJECTION_CHANGED,          MAP_PROJECTION_CHANGED,
115          LAYERS_CHANGED,          MAP_LAYERS_CHANGED,
116    
117          # layer channels forwarded by the map          # layer channels forwarded by the map
118          LAYER_PROJECTION_CHANGED,          LAYER_PROJECTION_CHANGED,
119          LAYER_LEGEND_CHANGED,          LAYER_CHANGED,
120          LAYER_VISIBILITY_CHANGED,          LAYER_VISIBILITY_CHANGED,
121    
122          # channels forwarded by an extension          # channels forwarded by an extension
# Line 63  class Session(TitledObject, Modifiable): Line 129  class Session(TitledObject, Modifiable):
129          self.filename = None          self.filename = None
130          self.maps = []          self.maps = []
131          self.tables = []          self.tables = []
132            self.shapestores = []
133          self.extensions = []          self.extensions = []
134            self.temp_dir = None
135            self.transient_db = None
136    
137        def changed(self, channel = None, *args):
138            """Like the inherited version but issue a CHANGED message as well.
139    
140            The CHANGED message is only issued if channel given is a
141            different channel than CHANGED.
142            """
143            Modifiable.changed(self, channel, *args)
144            if channel != CHANGED:
145                self.issue(CHANGED, self)
146    
147      def SetFilename(self, filename):      def SetFilename(self, filename):
148          self.filename = filename          self.filename = filename
# Line 81  class Session(TitledObject, Modifiable): Line 160  class Session(TitledObject, Modifiable):
160              map.Subscribe(channel, self.forward, channel)              map.Subscribe(channel, self.forward, channel)
161          self.changed(MAPS_CHANGED)          self.changed(MAPS_CHANGED)
162    
163        def RemoveMap(self, map):
164            for channel in self.forwarded_channels:
165                map.Unsubscribe(channel, self.forward, channel)
166            self.maps.remove(map)
167            self.changed(MAPS_CHANGED)
168            map.Destroy()
169    
170      def Extensions(self):      def Extensions(self):
171          return self.extensions          return self.extensions
172    
# Line 93  class Session(TitledObject, Modifiable): Line 179  class Session(TitledObject, Modifiable):
179              extension.Subscribe(channel, self.forward, channel)              extension.Subscribe(channel, self.forward, channel)
180          self.changed(EXTENSIONS_CHANGED)          self.changed(EXTENSIONS_CHANGED)
181    
182        def ShapeStores(self):
183            """Return a list of all ShapeStore objects open in the session"""
184            return [store() for store in self.shapestores]
185    
186        def _add_shapestore(self, store):
187            """Internal: Add the shapestore to the list of shapestores"""
188            self.shapestores.append(weakref.ref(store,
189                                                self._clean_weak_store_refs))
190    
191        def _clean_weak_store_refs(self, weakref):
192            """Internal: Remove the weakref from the shapestores list"""
193            self.shapestores = [store for store in self.shapestores
194                                      if store is not weakref]
195    
196        def Tables(self):
197            """Return a list of all table objects open in the session
198    
199            The list includes all tables that are indirectly opened through
200            shape stores and the tables that have been opened explicitly.
201            """
202            return self.tables + [store.Table() for store in self.ShapeStores()]
203    
204        def AddTable(self, table):
205            """Add the table to the session
206    
207            All tables associated with the session that are not implicitly
208            created by the OpenShapefile method (and maybe other Open*
209            methods in the future) have to be passed to this method to make
210            sure the session knows about it. The session keeps a reference
211            to the table. Only tables managed by the session in this way
212            should be used for layers contained in one of the session's
213            maps.
214    
215            The table parameter may be any object implementing the table
216            interface. If it's not already one of the transient tables
217            instantiate an AutoTransientTable with it and use that instead
218            of the original table (note that the AutoTransientTable keeps a
219            reference to the original table).
220    
221            Return the table object actually used by the session.
222            """
223            if not hasattr(table, "transient_table"):
224                transient_table = AutoTransientTable(self.TransientDB(), table)
225            else:
226                transient_table = table
227            self.tables.append(transient_table)
228            return transient_table
229    
230        def temp_directory(self):
231            """
232            Return the name of the directory for session specific temporary files
233    
234            Create the directory if it doesn't exist yet.
235            """
236            if self.temp_dir is None:
237                temp_dir = mktemp()
238                os.mkdir(temp_dir, 0700)
239                self.temp_dir = temp_dir
240                self.temp_dir_remover = AutoRemoveDir(self.temp_dir)
241            return self.temp_dir
242    
243        def OpenShapefile(self, filename):
244            """Return a shapefile store object for the data in the given file"""
245            store = ShapefileStore(self, filename)
246            self._add_shapestore(store)
247            return store
248    
249        def TransientDB(self):
250            if self.transient_db is None:
251                filename = os.path.join(self.temp_directory(), "transientdb")
252                self.transient_db = TransientDatabase(filename)
253                #print self.temp_dir_remover
254                auto_remover[self.transient_db] = AutoRemoveFile(filename,
255                                                            self.temp_dir_remover)
256            return self.transient_db
257    
258      def Destroy(self):      def Destroy(self):
259          for map in self.maps:          for map in self.maps:
260              map.Destroy()              map.Destroy()
261          self.maps = []          self.maps = []
262          self.tables = []          self.tables = []
263          Publisher.Destroy(self)          Modifiable.Destroy(self)
264    
265            # Close the transient DB explicitly so that it removes any
266            # journal files from the temporary directory
267            if self.transient_db is not None:
268                self.transient_db.close()
269    
270      def forward(self, *args):      def forward(self, *args):
271          """Reissue events"""          """Reissue events.
272    
273            If the channel the event is forwarded to is a changed-channel
274            that is not the CHANGED channel issue CHANGED as well. An
275            channel is considered to be a changed-channel if it's name ends
276            with 'CHANGED'.
277            """
278          if len(args) > 1:          if len(args) > 1:
279              args = (args[-1],) + args[:-1]              args = (args[-1],) + args[:-1]
280          apply(self.issue, args)          apply(self.issue, args)
281            channel = args[0]
282            # It's a bit of a kludge to rely on the channel name for this.
283            if channel.endswith("CHANGED") and channel != CHANGED:
284                self.issue(CHANGED, self)
285    
286      def WasModified(self):      def WasModified(self):
287          """Return true if the session or one of the maps was modified"""          """Return true if the session or one of the maps was modified"""
# Line 122  class Session(TitledObject, Modifiable): Line 299  class Session(TitledObject, Modifiable):
299          for map in self.maps:          for map in self.maps:
300              map.UnsetModified()              map.UnsetModified()
301    
302        def TreeInfo(self):
303            items = []
304            if self.filename is None:
305                items.append(_("Filename:"))
306            else:
307                items.append(_("Filename: %s") % self.filename)
308    
309            if self.WasModified():
310                items.append(_("Modified"))
311            else:
312                items.append(_("Unmodified"))
313    
314            items.extend(self.maps)
315            items.extend(self.extensions)
316    
317            return (_("Session: %s") % self.title, items)
318    
319    
320  def create_empty_session():  def create_empty_session():
321      """Return an empty session useful as a starting point"""      """Return an empty session useful as a starting point"""
322      import os      import os
323      session = Session('unnamed session')      session = Session(_('unnamed session'))
324      session.SetFilename(None)      session.SetFilename(None)
325      session.AddMap(Map('unnamed map'))      session.AddMap(Map(_('unnamed map')))
326      session.UnsetModified()      session.UnsetModified()
327      return session      return session
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