/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/session.py
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revision 6 by bh, Tue Aug 28 15:41:52 2001 UTC revision 1016 by bh, Fri May 23 11:05:59 2003 UTC
# Line 1  Line 1 
1  # Copyright (c) 2001 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]>
5  #  #
6  # This program is free software under the GPL (>=v2)  # This program is free software under the GPL (>=v2)
7  # Read the file COPYING coming with Thuban for details.  # Read the file COPYING coming with Thuban for details.
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, \
16         MAP_LAYERS_CHANGED, MAP_PROJECTION_CHANGED, \
17         LAYER_CHANGED, LAYER_PROJECTION_CHANGED, LAYER_VISIBILITY_CHANGED,\
18         EXTENSION_CHANGED, EXTENSION_OBJECTS_CHANGED, CHANGED
19    
20  from messages import MAPS_CHANGED, LAYERS_CHANGED, MAP_PROJECTION_CHANGED, \  from Thuban import _
      LAYER_LEGEND_CHANGED, FILENAME_CHANGED  
21    
22  from base import TitledObject, Modifiable  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.
82    
83      A Session consists of arbitrary numbers of maps and tables      A Session consists of arbitrary numbers of maps, tables and extensions
84    
85      Session objects send the following events:      Session objects send the following events:
86    
# Line 31  class Session(TitledObject, Modifiable): Line 90  class Session(TitledObject, Modifiable):
90    
91          MAPS_CHANGED -- Maps were added, removed.          MAPS_CHANGED -- Maps were added, removed.
92    
93          LAYERS_CHANGED -- Same as the map's event of the same name.          EXTENSIONS_CHANGED -- Extensions were added, removed.
94    
95            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
108        # the session.
109        forwarded_channels = (
110            # generic channels
111            CHANGED,
112    
113            # map specific channels
114            MAP_PROJECTION_CHANGED,
115            MAP_LAYERS_CHANGED,
116    
117            # layer channels forwarded by the map
118            LAYER_PROJECTION_CHANGED,
119            LAYER_CHANGED,
120            LAYER_VISIBILITY_CHANGED,
121    
122            # channels forwarded by an extension
123            EXTENSION_CHANGED,
124            EXTENSION_OBJECTS_CHANGED)
125    
126      def __init__(self, title):      def __init__(self, title):
127          TitledObject.__init__(self, title)          TitledObject.__init__(self, title)
128          Modifiable.__init__(self)          Modifiable.__init__(self)
129          self.filename = None          self.filename = None
130          self.maps = []          self.maps = []
131          self.tables = []          self.tables = []
132            self.shapestores = []
133            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 55  class Session(TitledObject, Modifiable): Line 156  class Session(TitledObject, Modifiable):
156    
157      def AddMap(self, map):      def AddMap(self, map):
158          self.maps.append(map)          self.maps.append(map)
159          for channel in (LAYERS_CHANGED, MAP_PROJECTION_CHANGED,          for channel in self.forwarded_channels:
                         LAYER_LEGEND_CHANGED):  
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):
171            return self.extensions
172    
173        def HasExtensions(self):
174            return len(self.extensions) > 0
175    
176        def AddExtension(self, extension):
177            self.extensions.append(extension)
178            for channel in self.forwarded_channels:
179                extension.Subscribe(channel, self.forward, channel)
180            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 AddShapeStore(self, shapestore):
262            """Add the shapestore to the session.
263    
264            The session only holds a weak reference to the shapestore, so it
265            will automatically be removed from the session when the last
266            reference goes away.
267            """
268            self._add_shapestore(shapestore)
269            return shapestore
270    
271        def TransientDB(self):
272            if self.transient_db is None:
273                filename = os.path.join(self.temp_directory(), "transientdb")
274                self.transient_db = TransientDatabase(filename)
275                #print self.temp_dir_remover
276                auto_remover[self.transient_db] = AutoRemoveFile(filename,
277                                                            self.temp_dir_remover)
278            return self.transient_db
279    
280      def Destroy(self):      def Destroy(self):
281          for map in self.maps:          for map in self.maps:
282              map.Destroy()              map.Destroy()
283          self.maps = []          self.maps = []
284          self.tables = []          self.tables = []
285          Publisher.Destroy(self)          Modifiable.Destroy(self)
286    
287            # Close the transient DB explicitly so that it removes any
288            # journal files from the temporary directory
289            if self.transient_db is not None:
290                self.transient_db.close()
291    
292      def forward(self, *args):      def forward(self, *args):
293          """Reissue events"""          """Reissue events.
294    
295            If the channel the event is forwarded to is a changed-channel
296            that is not the CHANGED channel issue CHANGED as well. An
297            channel is considered to be a changed-channel if it's name ends
298            with 'CHANGED'.
299            """
300          if len(args) > 1:          if len(args) > 1:
301              args = (args[-1],) + args[:-1]              args = (args[-1],) + args[:-1]
302          apply(self.issue, args)          apply(self.issue, args)
303            channel = args[0]
304            # It's a bit of a kludge to rely on the channel name for this.
305            if channel.endswith("CHANGED") and channel != CHANGED:
306                self.issue(CHANGED, self)
307    
308      def WasModified(self):      def WasModified(self):
309          """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 85  class Session(TitledObject, Modifiable): Line 317  class Session(TitledObject, Modifiable):
317    
318      def UnsetModified(self):      def UnsetModified(self):
319          """Unset the modified flag of the session and the maps"""          """Unset the modified flag of the session and the maps"""
         print "Session.UnsetModified: entry", self.modified  
320          Modifiable.UnsetModified(self)          Modifiable.UnsetModified(self)
321          for map in self.maps:          for map in self.maps:
322              map.UnsetModified()              map.UnsetModified()
         print "Session.UnsetModified: exit", self.modified  
323    
324        def TreeInfo(self):
325            items = []
326            if self.filename is None:
327                items.append(_("Filename:"))
328            else:
329                items.append(_("Filename: %s") % self.filename)
330    
331            if self.WasModified():
332                items.append(_("Modified"))
333            else:
334                items.append(_("Unmodified"))
335    
336            items.extend(self.maps)
337            items.extend(self.extensions)
338    
339            return (_("Session: %s") % self.title, items)
340    
341    
342  def create_empty_session():  def create_empty_session():
343      """Return an empty session useful as a starting point"""      """Return an empty session useful as a starting point"""
344      session = Session('unnamed session')      import os
345      session.SetFilename('unnamed.session')      session = Session(_('unnamed session'))
346      session.AddMap(Map('unnamed map'))      session.SetFilename(None)
347        session.AddMap(Map(_('unnamed map')))
348        session.UnsetModified()
349      return session      return session
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