/[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 1124 by bh, Mon Jun 2 14:14:25 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         TABLE_REMOVED
20    
21  from base import TitledObject, Modifiable  from Thuban import _
22    
23    from base import TitledObject, Modifiable
24  from map import Map  from map import Map
25    from data import ShapefileStore
26    from table import DBFTable
27    
28    from transientdb import TransientDatabase, AutoTransientTable
29    
30    class AutoRemoveFile:
31    
32        """Remove a file once all references go away."""
33    
34        def __init__(self, filename, tempdir = None):
35            """Initialize the AutoRemoveFile
36    
37            Parameters:
38               filename -- The name of the file to remove in __del__
39               tempdir -- Another object simple stored as an instance variable.
40    
41            As the name suggests the tempdir parameter is intended for a
42            temporary directory the file might be located in. The intended
43            use is that it's an instance of AutoRemoveDir.
44            """
45            self.filename = filename
46            self.tempdir = tempdir
47    
48        def __del__(self, remove = os.remove):
49            remove(self.filename)
50    
51    class AutoRemoveDir:
52    
53        """Remove a directory once all references go away
54    
55        The intended use of this class together with AutoRemoveFile is for
56        temporary directories and files containd therein. An AutoRemoveDir
57        should be instantiated for the directory and passed as the tempdir
58        parameter to every AutoRemoveFile instance created for files in the
59        directory. An AutoRemoveFile shold be instantiated for every file
60        created in the directory so that the directory is automatically
61        removed once the last file is removed.
62        """
63    
64        def __init__(self, filename):
65            """Initialize the AutoRemoveDir
66    
67            The parameter is the name of the directory.
68            """
69            self.filename = filename
70    
71        def __del__(self, rmdir = os.rmdir):
72            rmdir(self.filename)
73    
74    
75    # WeakKey dictionary mapping objects like the transient_db to
76    # AutoRemoveDir or AutoRemoveFile instances to make sure that the
77    # temporary files and the directory are deleted but not before the
78    # objects that use them go away.
79    auto_remover = weakref.WeakKeyDictionary()
80    
81  class Session(TitledObject, Modifiable):  class Session(TitledObject, Modifiable):
82    
# Line 36  class Session(TitledObject, Modifiable): Line 94  class Session(TitledObject, Modifiable):
94    
95          EXTENSIONS_CHANGED -- Extensions were added, removed.          EXTENSIONS_CHANGED -- Extensions were added, removed.
96    
97          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.
98                            It's simply resent from the session to make                            It's simply resent from the session to make
99                            subscriptions easier.                            subscriptions easier.
100    
# Line 51  class Session(TitledObject, Modifiable): Line 109  class Session(TitledObject, Modifiable):
109      # message channels that have to be forwarded from maps contained in      # message channels that have to be forwarded from maps contained in
110      # the session.      # the session.
111      forwarded_channels = (      forwarded_channels = (
112            # generic channels
113            CHANGED,
114    
115          # map specific channels          # map specific channels
116          MAP_PROJECTION_CHANGED,          MAP_PROJECTION_CHANGED,
117          LAYERS_CHANGED,          MAP_LAYERS_CHANGED,
118    
119          # layer channels forwarded by the map          # layer channels forwarded by the map
120          LAYER_PROJECTION_CHANGED,          LAYER_PROJECTION_CHANGED,
121          LAYER_LEGEND_CHANGED,          LAYER_CHANGED,
122          LAYER_VISIBILITY_CHANGED,          LAYER_VISIBILITY_CHANGED,
123    
124          # channels forwarded by an extension          # channels forwarded by an extension
# Line 70  class Session(TitledObject, Modifiable): Line 131  class Session(TitledObject, Modifiable):
131          self.filename = None          self.filename = None
132          self.maps = []          self.maps = []
133          self.tables = []          self.tables = []
134            self.shapestores = []
135          self.extensions = []          self.extensions = []
136            self.temp_dir = None
137            self.transient_db = None
138    
139      def changed(self, channel = None, *args):      def changed(self, channel = None, *args):
140          """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 162  class Session(TitledObject, Modifiable):
162              map.Subscribe(channel, self.forward, channel)              map.Subscribe(channel, self.forward, channel)
163          self.changed(MAPS_CHANGED)          self.changed(MAPS_CHANGED)
164    
165        def RemoveMap(self, map):
166            for channel in self.forwarded_channels:
167                map.Unsubscribe(channel, self.forward, channel)
168            self.maps.remove(map)
169            self.changed(MAPS_CHANGED)
170            map.Destroy()
171    
172      def Extensions(self):      def Extensions(self):
173          return self.extensions          return self.extensions
174    
# Line 110  class Session(TitledObject, Modifiable): Line 181  class Session(TitledObject, Modifiable):
181              extension.Subscribe(channel, self.forward, channel)              extension.Subscribe(channel, self.forward, channel)
182          self.changed(EXTENSIONS_CHANGED)          self.changed(EXTENSIONS_CHANGED)
183    
184        def ShapeStores(self):
185            """Return a list of all ShapeStore objects open in the session"""
186            return [store() for store in self.shapestores]
187    
188        def _add_shapestore(self, store):
189            """Internal: Add the shapestore to the list of shapestores"""
190            self.shapestores.append(weakref.ref(store,
191                                                self._clean_weak_store_refs))
192    
193        def _clean_weak_store_refs(self, weakref):
194            """Internal: Remove the weakref from the shapestores list"""
195            self.shapestores = [store for store in self.shapestores
196                                      if store is not weakref]
197    
198        def Tables(self):
199            """Return a list of all table objects open in the session
200    
201            The list includes all tables that are indirectly opened through
202            shape stores and the tables that have been opened explicitly.
203            """
204            return self.tables + [store.Table() for store in self.ShapeStores()]
205    
206        def UnreferencedTables(self):
207            """Return the tables that are not referenced by other data sources"""
208            known = {}
209            for table in self.tables:
210                known[id(table)] = 0
211            for table in self.tables + self.ShapeStores():
212                for dep in table.Dependencies():
213                    known[id(dep)] = 1
214            return [table for table in self.tables if known[id(table)] == 0]
215    
216        def AddTable(self, table):
217            """Add the table to the session
218    
219            All tables associated with the session that are not implicitly
220            created by the OpenShapefile method (and maybe other Open*
221            methods in the future) have to be passed to this method to make
222            sure the session knows about it. The session keeps a reference
223            to the table. Only tables managed by the session in this way
224            should be used for layers contained in one of the session's
225            maps.
226    
227            The table parameter may be any object implementing the table
228            interface. If it's not already one of the transient tables
229            instantiate an AutoTransientTable with it and use that instead
230            of the original table (note that the AutoTransientTable keeps a
231            reference to the original table).
232    
233            Return the table object actually used by the session.
234            """
235            if not hasattr(table, "transient_table"):
236                transient_table = AutoTransientTable(self.TransientDB(), table)
237            else:
238                transient_table = table
239            self.tables.append(transient_table)
240            self.changed()
241            return transient_table
242    
243        def RemoveTable(self, table):
244            """Remove the table from the session.
245    
246            The table object must be a table object previously returned by
247            the AddTable method. If the table is not part of the session
248            raise a ValueError.
249    
250            Issue a TABLE_REMOVED message after the table has been removed.
251            The message has the removed table as the single parameter.
252            """
253            tables = [t for t in self.tables if t is not table]
254            if len(tables) == len(self.tables):
255                raise ValueError
256            self.tables = tables
257            self.changed(TABLE_REMOVED, table)
258    
259        def OpenTableFile(self, filename):
260            """Open the table file filename and return the table object.
261    
262            The filename argument must be the name of a DBF file.
263            """
264            return self.AddTable(DBFTable(filename))
265    
266        def temp_directory(self):
267            """
268            Return the name of the directory for session specific temporary files
269    
270            Create the directory if it doesn't exist yet.
271            """
272            if self.temp_dir is None:
273                temp_dir = mktemp()
274                os.mkdir(temp_dir, 0700)
275                self.temp_dir = temp_dir
276                self.temp_dir_remover = AutoRemoveDir(self.temp_dir)
277            return self.temp_dir
278    
279        def OpenShapefile(self, filename):
280            """Return a shapefile store object for the data in the given file"""
281            store = ShapefileStore(self, filename)
282            self._add_shapestore(store)
283            return store
284    
285        def AddShapeStore(self, shapestore):
286            """Add the shapestore to the session.
287    
288            The session only holds a weak reference to the shapestore, so it
289            will automatically be removed from the session when the last
290            reference goes away.
291            """
292            self._add_shapestore(shapestore)
293            return shapestore
294    
295        def TransientDB(self):
296            if self.transient_db is None:
297                filename = os.path.join(self.temp_directory(), "transientdb")
298                self.transient_db = TransientDatabase(filename)
299                #print self.temp_dir_remover
300                auto_remover[self.transient_db] = AutoRemoveFile(filename,
301                                                            self.temp_dir_remover)
302            return self.transient_db
303    
304      def Destroy(self):      def Destroy(self):
305          for map in self.maps:          for map in self.maps:
306              map.Destroy()              map.Destroy()
307          self.maps = []          self.maps = []
308          self.tables = []          self.tables = []
309          Publisher.Destroy(self)          Modifiable.Destroy(self)
310    
311            # Close the transient DB explicitly so that it removes any
312            # journal files from the temporary directory
313            if self.transient_db is not None:
314                self.transient_db.close()
315    
316      def forward(self, *args):      def forward(self, *args):
317          """Reissue events.          """Reissue events.
# Line 152  class Session(TitledObject, Modifiable): Line 348  class Session(TitledObject, Modifiable):
348      def TreeInfo(self):      def TreeInfo(self):
349          items = []          items = []
350          if self.filename is None:          if self.filename is None:
351              items.append("Filename:")              items.append(_("Filename:"))
352          else:          else:
353              items.append("Filename: %s" % self.filename)              items.append(_("Filename: %s") % self.filename)
354    
355          if self.WasModified():          if self.WasModified():
356              items.append("Modified")              items.append(_("Modified"))
357          else:          else:
358              items.append("Unmodified")              items.append(_("Unmodified"))
359    
360          items.extend(self.maps)          items.extend(self.maps)
361          items.extend(self.extensions)          items.extend(self.extensions)
362    
363          return ("Session: %s" % self.title, items)          return (_("Session: %s") % self.title, items)
364    
365    
366  def create_empty_session():  def create_empty_session():
367      """Return an empty session useful as a starting point"""      """Return an empty session useful as a starting point"""
368      import os      import os
369      session = Session('unnamed session')      session = Session(_('unnamed session'))
370      session.SetFilename(None)      session.SetFilename(None)
371      session.AddMap(Map('unnamed map'))      session.AddMap(Map(_('unnamed map')))
372      session.UnsetModified()      session.UnsetModified()
373      return session      return session
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