/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/session.py
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revision 27 by bh, Thu Sep 6 13:27:52 2001 UTC revision 1036 by bh, Mon May 26 17:30:29 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    from table import DBFTable
26    
27    from transientdb import TransientDatabase, AutoTransientTable
28    
29    class AutoRemoveFile:
30    
31        """Remove a file once all references go away."""
32    
33        def __init__(self, filename, tempdir = None):
34            """Initialize the AutoRemoveFile
35    
36            Parameters:
37               filename -- The name of the file to remove in __del__
38               tempdir -- Another object simple stored as an instance variable.
39    
40            As the name suggests the tempdir parameter is intended for a
41            temporary directory the file might be located in. The intended
42            use is that it's an instance of AutoRemoveDir.
43            """
44            self.filename = filename
45            self.tempdir = tempdir
46    
47        def __del__(self, remove = os.remove):
48            remove(self.filename)
49    
50    class AutoRemoveDir:
51    
52        """Remove a directory once all references go away
53    
54        The intended use of this class together with AutoRemoveFile is for
55        temporary directories and files containd therein. An AutoRemoveDir
56        should be instantiated for the directory and passed as the tempdir
57        parameter to every AutoRemoveFile instance created for files in the
58        directory. An AutoRemoveFile shold be instantiated for every file
59        created in the directory so that the directory is automatically
60        removed once the last file is removed.
61        """
62    
63        def __init__(self, filename):
64            """Initialize the AutoRemoveDir
65    
66            The parameter is the name of the directory.
67            """
68            self.filename = filename
69    
70        def __del__(self, rmdir = os.rmdir):
71            rmdir(self.filename)
72    
73    
74    # WeakKey dictionary mapping objects like the transient_db to
75    # AutoRemoveDir or AutoRemoveFile instances to make sure that the
76    # temporary files and the directory are deleted but not before the
77    # objects that use them go away.
78    auto_remover = weakref.WeakKeyDictionary()
79    
80  class Session(TitledObject, Modifiable):  class Session(TitledObject, Modifiable):
81    
82      """A complete session.      """A complete session.
83    
84      A Session consists of arbitrary numbers of maps and tables      A Session consists of arbitrary numbers of maps, tables and extensions
85    
86      Session objects send the following events:      Session objects send the following events:
87    
# Line 31  class Session(TitledObject, Modifiable): Line 91  class Session(TitledObject, Modifiable):
91    
92          MAPS_CHANGED -- Maps were added, removed.          MAPS_CHANGED -- Maps were added, removed.
93    
94          LAYERS_CHANGED -- Same as the map's event of the same name.          EXTENSIONS_CHANGED -- Extensions were added, removed.
95    
96            MAP_LAYERS_CHANGED -- Same as the map's event of the same name.
97                            It's simply resent from the session to make                            It's simply resent from the session to make
98                            subscriptions easier.                            subscriptions easier.
99    
100            CHANGED -- Generic changed event. Parameters: the session. The
101                       event is always issued when any other changed event
102                       is issused. This is useful for code that needs to be
103                       notified whenever something in the session has
104                       changed but it's too cumbersome or error-prone to
105                       subscribe to all the individual events.
106      """      """
107    
108        # message channels that have to be forwarded from maps contained in
109        # the session.
110        forwarded_channels = (
111            # generic channels
112            CHANGED,
113    
114            # map specific channels
115            MAP_PROJECTION_CHANGED,
116            MAP_LAYERS_CHANGED,
117    
118            # layer channels forwarded by the map
119            LAYER_PROJECTION_CHANGED,
120            LAYER_CHANGED,
121            LAYER_VISIBILITY_CHANGED,
122    
123            # channels forwarded by an extension
124            EXTENSION_CHANGED,
125            EXTENSION_OBJECTS_CHANGED)
126    
127      def __init__(self, title):      def __init__(self, title):
128          TitledObject.__init__(self, title)          TitledObject.__init__(self, title)
129          Modifiable.__init__(self)          Modifiable.__init__(self)
130          self.filename = None          self.filename = None
131          self.maps = []          self.maps = []
132          self.tables = []          self.tables = []
133            self.shapestores = []
134            self.extensions = []
135            self.temp_dir = None
136            self.transient_db = None
137    
138        def changed(self, channel = None, *args):
139            """Like the inherited version but issue a CHANGED message as well.
140    
141            The CHANGED message is only issued if channel given is a
142            different channel than CHANGED.
143            """
144            Modifiable.changed(self, channel, *args)
145            if channel != CHANGED:
146                self.issue(CHANGED, self)
147    
148      def SetFilename(self, filename):      def SetFilename(self, filename):
149          self.filename = filename          self.filename = filename
# Line 55  class Session(TitledObject, Modifiable): Line 157  class Session(TitledObject, Modifiable):
157    
158      def AddMap(self, map):      def AddMap(self, map):
159          self.maps.append(map)          self.maps.append(map)
160          for channel in (LAYERS_CHANGED, MAP_PROJECTION_CHANGED,          for channel in self.forwarded_channels:
                         LAYER_LEGEND_CHANGED):  
161              map.Subscribe(channel, self.forward, channel)              map.Subscribe(channel, self.forward, channel)
162          self.changed(MAPS_CHANGED)          self.changed(MAPS_CHANGED)
163    
164        def RemoveMap(self, map):
165            for channel in self.forwarded_channels:
166                map.Unsubscribe(channel, self.forward, channel)
167            self.maps.remove(map)
168            self.changed(MAPS_CHANGED)
169            map.Destroy()
170    
171        def Extensions(self):
172            return self.extensions
173    
174        def HasExtensions(self):
175            return len(self.extensions) > 0
176    
177        def AddExtension(self, extension):
178            self.extensions.append(extension)
179            for channel in self.forwarded_channels:
180                extension.Subscribe(channel, self.forward, channel)
181            self.changed(EXTENSIONS_CHANGED)
182    
183        def ShapeStores(self):
184            """Return a list of all ShapeStore objects open in the session"""
185            return [store() for store in self.shapestores]
186    
187        def _add_shapestore(self, store):
188            """Internal: Add the shapestore to the list of shapestores"""
189            self.shapestores.append(weakref.ref(store,
190                                                self._clean_weak_store_refs))
191    
192        def _clean_weak_store_refs(self, weakref):
193            """Internal: Remove the weakref from the shapestores list"""
194            self.shapestores = [store for store in self.shapestores
195                                      if store is not weakref]
196    
197        def Tables(self):
198            """Return a list of all table objects open in the session
199    
200            The list includes all tables that are indirectly opened through
201            shape stores and the tables that have been opened explicitly.
202            """
203            return self.tables + [store.Table() for store in self.ShapeStores()]
204    
205        def AddTable(self, table):
206            """Add the table to the session
207    
208            All tables associated with the session that are not implicitly
209            created by the OpenShapefile method (and maybe other Open*
210            methods in the future) have to be passed to this method to make
211            sure the session knows about it. The session keeps a reference
212            to the table. Only tables managed by the session in this way
213            should be used for layers contained in one of the session's
214            maps.
215    
216            The table parameter may be any object implementing the table
217            interface. If it's not already one of the transient tables
218            instantiate an AutoTransientTable with it and use that instead
219            of the original table (note that the AutoTransientTable keeps a
220            reference to the original table).
221    
222            Return the table object actually used by the session.
223            """
224            if not hasattr(table, "transient_table"):
225                transient_table = AutoTransientTable(self.TransientDB(), table)
226            else:
227                transient_table = table
228            self.tables.append(transient_table)
229            return transient_table
230    
231        def RemoveTable(self, table):
232            """Remove the table from the session.
233    
234            The table object must be a table object previously returned by
235            the AddTable method. If the table is not part of the session
236            raise a ValueError.
237            """
238            tables = [t for t in self.tables if t is not table]
239            if len(tables) == len(self.tables):
240                raise ValueError
241            self.tables = tables
242    
243        def OpenTableFile(self, filename):
244            """Open the table file filename and return the table object.
245    
246            The filename argument must be the name of a DBF file.
247            """
248            return self.AddTable(DBFTable(filename))
249    
250        def temp_directory(self):
251            """
252            Return the name of the directory for session specific temporary files
253    
254            Create the directory if it doesn't exist yet.
255            """
256            if self.temp_dir is None:
257                temp_dir = mktemp()
258                os.mkdir(temp_dir, 0700)
259                self.temp_dir = temp_dir
260                self.temp_dir_remover = AutoRemoveDir(self.temp_dir)
261            return self.temp_dir
262    
263        def OpenShapefile(self, filename):
264            """Return a shapefile store object for the data in the given file"""
265            store = ShapefileStore(self, filename)
266            self._add_shapestore(store)
267            return store
268    
269        def AddShapeStore(self, shapestore):
270            """Add the shapestore to the session.
271    
272            The session only holds a weak reference to the shapestore, so it
273            will automatically be removed from the session when the last
274            reference goes away.
275            """
276            self._add_shapestore(shapestore)
277            return shapestore
278    
279        def TransientDB(self):
280            if self.transient_db is None:
281                filename = os.path.join(self.temp_directory(), "transientdb")
282                self.transient_db = TransientDatabase(filename)
283                #print self.temp_dir_remover
284                auto_remover[self.transient_db] = AutoRemoveFile(filename,
285                                                            self.temp_dir_remover)
286            return self.transient_db
287    
288      def Destroy(self):      def Destroy(self):
289          for map in self.maps:          for map in self.maps:
290              map.Destroy()              map.Destroy()
291          self.maps = []          self.maps = []
292          self.tables = []          self.tables = []
293          Publisher.Destroy(self)          Modifiable.Destroy(self)
294    
295            # Close the transient DB explicitly so that it removes any
296            # journal files from the temporary directory
297            if self.transient_db is not None:
298                self.transient_db.close()
299    
300      def forward(self, *args):      def forward(self, *args):
301          """Reissue events"""          """Reissue events.
302    
303            If the channel the event is forwarded to is a changed-channel
304            that is not the CHANGED channel issue CHANGED as well. An
305            channel is considered to be a changed-channel if it's name ends
306            with 'CHANGED'.
307            """
308          if len(args) > 1:          if len(args) > 1:
309              args = (args[-1],) + args[:-1]              args = (args[-1],) + args[:-1]
310          apply(self.issue, args)          apply(self.issue, args)
311            channel = args[0]
312            # It's a bit of a kludge to rely on the channel name for this.
313            if channel.endswith("CHANGED") and channel != CHANGED:
314                self.issue(CHANGED, self)
315    
316      def WasModified(self):      def WasModified(self):
317          """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 89  class Session(TitledObject, Modifiable): Line 329  class Session(TitledObject, Modifiable):
329          for map in self.maps:          for map in self.maps:
330              map.UnsetModified()              map.UnsetModified()
331    
332        def TreeInfo(self):
333            items = []
334            if self.filename is None:
335                items.append(_("Filename:"))
336            else:
337                items.append(_("Filename: %s") % self.filename)
338    
339            if self.WasModified():
340                items.append(_("Modified"))
341            else:
342                items.append(_("Unmodified"))
343    
344            items.extend(self.maps)
345            items.extend(self.extensions)
346    
347            return (_("Session: %s") % self.title, items)
348    
349    
350  def create_empty_session():  def create_empty_session():
351      """Return an empty session useful as a starting point"""      """Return an empty session useful as a starting point"""
352      session = Session('unnamed session')      import os
353      session.SetFilename('unnamed.session')      session = Session(_('unnamed session'))
354      session.AddMap(Map('unnamed map'))      session.SetFilename(None)
355        session.AddMap(Map(_('unnamed map')))
356        session.UnsetModified()
357      return session      return session
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