/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/session.py
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revision 232 by bh, Fri Jul 19 15:14:57 2002 UTC revision 987 by bh, Thu May 22 16:46:14 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, 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    
# Line 51  class Session(TitledObject, Modifiable): Line 107  class Session(TitledObject, Modifiable):
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 70  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):      def changed(self, channel = None, *args):
138          """Like the inherited version but issue a CHANGED message as well.          """Like the inherited version but issue a CHANGED message as well.
# Line 98  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 110  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 RemoveTable(self, table):
231            """Remove the table from the session.
232    
233            The table object must be a table object previously returned by
234            the AddTable method. If the table is not part of the session
235            raise a ValueError.
236            """
237            tables = [t for t in self.tables if t is not table]
238            if len(tables) == len(self.tables):
239                raise ValueError
240            self.tables = tables
241    
242        def temp_directory(self):
243            """
244            Return the name of the directory for session specific temporary files
245    
246            Create the directory if it doesn't exist yet.
247            """
248            if self.temp_dir is None:
249                temp_dir = mktemp()
250                os.mkdir(temp_dir, 0700)
251                self.temp_dir = temp_dir
252                self.temp_dir_remover = AutoRemoveDir(self.temp_dir)
253            return self.temp_dir
254    
255        def OpenShapefile(self, filename):
256            """Return a shapefile store object for the data in the given file"""
257            store = ShapefileStore(self, filename)
258            self._add_shapestore(store)
259            return store
260    
261        def TransientDB(self):
262            if self.transient_db is None:
263                filename = os.path.join(self.temp_directory(), "transientdb")
264                self.transient_db = TransientDatabase(filename)
265                #print self.temp_dir_remover
266                auto_remover[self.transient_db] = AutoRemoveFile(filename,
267                                                            self.temp_dir_remover)
268            return self.transient_db
269    
270      def Destroy(self):      def Destroy(self):
271          for map in self.maps:          for map in self.maps:
272              map.Destroy()              map.Destroy()
273          self.maps = []          self.maps = []
274          self.tables = []          self.tables = []
275          Publisher.Destroy(self)          Modifiable.Destroy(self)
276    
277            # Close the transient DB explicitly so that it removes any
278            # journal files from the temporary directory
279            if self.transient_db is not None:
280                self.transient_db.close()
281    
282      def forward(self, *args):      def forward(self, *args):
283          """Reissue events.          """Reissue events.
# Line 152  class Session(TitledObject, Modifiable): Line 314  class Session(TitledObject, Modifiable):
314      def TreeInfo(self):      def TreeInfo(self):
315          items = []          items = []
316          if self.filename is None:          if self.filename is None:
317              items.append("Filename:")              items.append(_("Filename:"))
318          else:          else:
319              items.append("Filename: %s" % self.filename)              items.append(_("Filename: %s") % self.filename)
320    
321          if self.WasModified():          if self.WasModified():
322              items.append("Modified")              items.append(_("Modified"))
323          else:          else:
324              items.append("Unmodified")              items.append(_("Unmodified"))
325    
326          items.extend(self.maps)          items.extend(self.maps)
327          items.extend(self.extensions)          items.extend(self.extensions)
328    
329          return ("Session: %s" % self.title, items)          return (_("Session: %s") % self.title, items)
330    
331    
332  def create_empty_session():  def create_empty_session():
333      """Return an empty session useful as a starting point"""      """Return an empty session useful as a starting point"""
334      import os      import os
335      session = Session('unnamed session')      session = Session(_('unnamed session'))
336      session.SetFilename(None)      session.SetFilename(None)
337      session.AddMap(Map('unnamed map'))      session.AddMap(Map(_('unnamed map')))
338      session.UnsetModified()      session.UnsetModified()
339      return session      return session
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