/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/session.py
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trunk/thuban/Thuban/Model/session.py revision 241 by bh, Wed Jul 24 17:16:17 2002 UTC branches/WIP-pyshapelib-bramz/Thuban/Model/session.py revision 2734 by bramz, Thu Mar 1 12:42:59 2007 UTC
# Line 1  Line 1 
1  # Copyright (c) 2001, 2002 by Intevation GmbH  # Copyright (c) 2001, 2002, 2003, 2004 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, DBCONN_ADDED, DBCONN_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    import postgisdb
28    
29    from transientdb import TransientDatabase, AutoTransientTable
30    
31    class AutoRemoveFile:
32    
33        """Remove a file once all references go away."""
34    
35        def __init__(self, filename, tempdir = None):
36            """Initialize the AutoRemoveFile
37    
38            Parameters:
39               filename -- The name of the file to remove in __del__
40               tempdir -- Another object simple stored as an instance variable.
41    
42            As the name suggests the tempdir parameter is intended for a
43            temporary directory the file might be located in. The intended
44            use is that it's an instance of AutoRemoveDir.
45            """
46            self.filename = filename
47            self.tempdir = tempdir
48    
49        def __del__(self, remove = os.remove):
50            remove(self.filename)
51    
52    class AutoRemoveDir:
53    
54        """Remove a directory once all references go away
55    
56        The intended use of this class together with AutoRemoveFile is for
57        temporary directories and files containd therein. An AutoRemoveDir
58        should be instantiated for the directory and passed as the tempdir
59        parameter to every AutoRemoveFile instance created for files in the
60        directory. An AutoRemoveFile shold be instantiated for every file
61        created in the directory so that the directory is automatically
62        removed once the last file is removed.
63        """
64    
65        def __init__(self, filename):
66            """Initialize the AutoRemoveDir
67    
68            The parameter is the name of the directory.
69            """
70            self.filename = filename
71    
72        def __del__(self, rmdir = os.rmdir):
73            rmdir(self.filename)
74    
75    
76    # WeakKey dictionary mapping objects like the transient_db to
77    # AutoRemoveDir or AutoRemoveFile instances to make sure that the
78    # temporary files and the directory are deleted but not before the
79    # objects that use them go away.
80    auto_remover = weakref.WeakKeyDictionary()
81    
82  class Session(TitledObject, Modifiable):  class Session(TitledObject, Modifiable):
83    
# Line 36  class Session(TitledObject, Modifiable): Line 95  class Session(TitledObject, Modifiable):
95    
96          EXTENSIONS_CHANGED -- Extensions were added, removed.          EXTENSIONS_CHANGED -- Extensions were added, removed.
97    
98          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.
99                            It's simply resent from the session to make                            It's simply resent from the session to make
100                            subscriptions easier.                            subscriptions easier.
101    
# Line 51  class Session(TitledObject, Modifiable): Line 110  class Session(TitledObject, Modifiable):
110      # message channels that have to be forwarded from maps contained in      # message channels that have to be forwarded from maps contained in
111      # the session.      # the session.
112      forwarded_channels = (      forwarded_channels = (
113            # generic channels
114            CHANGED,
115    
116          # map specific channels          # map specific channels
117          MAP_PROJECTION_CHANGED,          MAP_PROJECTION_CHANGED,
118          LAYERS_CHANGED,          MAP_LAYERS_CHANGED,
119    
120          # layer channels forwarded by the map          # layer channels forwarded by the map
121          LAYER_PROJECTION_CHANGED,          LAYER_PROJECTION_CHANGED,
122          LAYER_LEGEND_CHANGED,          LAYER_CHANGED,
123          LAYER_VISIBILITY_CHANGED,          LAYER_VISIBILITY_CHANGED,
124    
125          # channels forwarded by an extension          # channels forwarded by an extension
# Line 70  class Session(TitledObject, Modifiable): Line 132  class Session(TitledObject, Modifiable):
132          self.filename = None          self.filename = None
133          self.maps = []          self.maps = []
134          self.tables = []          self.tables = []
135            self.shapestores = []
136          self.extensions = []          self.extensions = []
137            self.db_connections = []
138            self.temp_dir = None
139            self.transient_db = None
140    
141      def changed(self, channel = None, *args):      def changed(self, channel = None, *args):
142          """Like the inherited version but issue a CHANGED message as well.          """Like the inherited version but issue a CHANGED message as well.
# Line 117  class Session(TitledObject, Modifiable): Line 183  class Session(TitledObject, Modifiable):
183              extension.Subscribe(channel, self.forward, channel)              extension.Subscribe(channel, self.forward, channel)
184          self.changed(EXTENSIONS_CHANGED)          self.changed(EXTENSIONS_CHANGED)
185    
186        def ShapeStores(self):
187            """Return a list of all ShapeStore objects open in the session"""
188            return [store() for store in self.shapestores]
189    
190        def _add_shapestore(self, store):
191            """Internal: Add the shapestore to the list of shapestores"""
192            self.shapestores.append(weakref.ref(store,
193                                                self._clean_weak_store_refs))
194    
195        def _clean_weak_store_refs(self, weakref):
196            """Internal: Remove the weakref from the shapestores list"""
197            self.shapestores = [store for store in self.shapestores
198                                      if store is not weakref]
199    
200        def Tables(self):
201            """Return a list of all table objects open in the session
202    
203            The list includes all tables that are indirectly opened through
204            shape stores and the tables that have been opened explicitly.
205            """
206            tables = self.tables[:]
207            ids = {}
208            for t in tables:
209                ids[id(t)] = 1
210            for store in self.ShapeStores():
211                t = store.Table()
212                if id(t) not in ids:
213                    ids[id(t)] = 1
214                    tables.append(t)
215            return tables
216    
217        def UnreferencedTables(self):
218            """Return the tables that are not referenced by other data sources"""
219            known = {}
220            for table in self.tables:
221                known[id(table)] = 0
222            for table in self.tables + self.ShapeStores():
223                for dep in table.Dependencies():
224                    known[id(dep)] = 1
225            return [table for table in self.tables if known[id(table)] == 0]
226    
227        def AddTable(self, table):
228            """Add the table to the session
229    
230            All tables associated with the session that are not implicitly
231            created by the OpenShapefile method (and maybe other Open*
232            methods in the future) have to be passed to this method to make
233            sure the session knows about it. The session keeps a reference
234            to the table. Only tables managed by the session in this way
235            should be used for layers contained in one of the session's
236            maps.
237    
238            The table parameter may be any object implementing the table
239            interface. If it's not already one of the transient tables
240            instantiate an AutoTransientTable with it and use that instead
241            of the original table (note that the AutoTransientTable keeps a
242            reference to the original table).
243    
244            Return the table object actually used by the session.
245            """
246            if not hasattr(table, "transient_table"):
247                transient_table = AutoTransientTable(self.TransientDB(), table)
248            else:
249                transient_table = table
250            self.tables.append(transient_table)
251            self.changed()
252            return transient_table
253    
254        def RemoveTable(self, table):
255            """Remove the table from the session.
256    
257            The table object must be a table object previously returned by
258            the AddTable method. If the table is not part of the session
259            raise a ValueError.
260    
261            Issue a TABLE_REMOVED message after the table has been removed.
262            The message has the removed table as the single parameter.
263            """
264            tables = [t for t in self.tables if t is not table]
265            if len(tables) == len(self.tables):
266                raise ValueError
267            self.tables = tables
268            self.changed(TABLE_REMOVED, table)
269    
270        def DataContainers(self):
271            """Return all data containers, i.e. shapestores and tables"""
272            return self.tables + self.ShapeStores()
273    
274        def OpenTableFile(self, filename):
275            """Open the table file filename and return the table object.
276    
277            The filename argument must be the name of a DBF file.
278            """
279            return self.AddTable(DBFTable(filename))
280    
281        def temp_directory(self):
282            """
283            Return the name of the directory for session specific temporary files
284    
285            Create the directory if it doesn't exist yet.
286            """
287            if self.temp_dir is None:
288                temp_dir = mktemp()
289                os.mkdir(temp_dir, 0700)
290                self.temp_dir = temp_dir
291                self.temp_dir_remover = AutoRemoveDir(self.temp_dir)
292            return self.temp_dir
293    
294        def OpenShapefile(self, filename):
295            """Return a shapefile store object for the data in the given file"""
296            store = ShapefileStore(self, filename)
297            self._add_shapestore(store)
298            return store
299    
300        def AddShapeStore(self, shapestore):
301            """Add the shapestore to the session.
302    
303            The session only holds a weak reference to the shapestore, so it
304            will automatically be removed from the session when the last
305            reference goes away.
306            """
307            self._add_shapestore(shapestore)
308            return shapestore
309    
310        def TransientDB(self):
311            if self.transient_db is None:
312                filename = os.path.join(self.temp_directory(), "transientdb")
313                self.transient_db = TransientDatabase(filename)
314                #print self.temp_dir_remover
315                auto_remover[self.transient_db] = AutoRemoveFile(filename,
316                                                            self.temp_dir_remover)
317            return self.transient_db
318    
319        def AddDBConnection(self, dbconn):
320            """Add the database connection dbconn to the session
321    
322            The argument should be an instance of PostGISConnection.
323            """
324            self.db_connections.append(dbconn)
325            self.changed(DBCONN_ADDED)
326    
327        def DBConnections(self):
328            """
329            Return a list of all database connections registered with the session
330            """
331            return self.db_connections
332    
333        def HasDBConnections(self):
334            """Return whether the session has open database connections"""
335            return bool(self.db_connections)
336    
337        def CanRemoveDBConnection(self, dbconn):
338            """Return whether the database connections dbconn can be removed
339    
340            If can be removed if none of the shapestores or tables in the
341            session references it.
342            """
343            for store in self.ShapeStores():
344                if (isinstance(store, postgisdb.PostGISShapeStore)
345                    and store.db is dbconn):
346                    return 0
347            for table in self.Tables():
348                if (isinstance(table, postgisdb.PostGISTable)
349                    and table.db is dbconn):
350                    return 0
351            return 1
352    
353        def RemoveDBConnection(self, dbconn):
354            """Remove the database connection from the session
355    
356            The parameter must be a connection that was registered
357            previously by a AddDBConnection() call.
358            """
359            if self.CanRemoveDBConnection(dbconn):
360                remaining = [c for c in self.db_connections if c is not dbconn]
361                if len(remaining) < len(self.db_connections):
362                    self.db_connections = remaining
363                    self.changed(DBCONN_REMOVED)
364                else:
365                    raise ValueError("DBConection %r is not registered"
366                                     " with session %r" % (dbconn, self))
367            else:
368                raise ValueError("DBConnection %r is still in use" % (dbconn,))
369    
370        def OpenDBShapeStore(self, db, tablename, id_column = None,
371                             geometry_column = None):
372            """Create and return a shapstore for a table in the database
373    
374            The db parameter must be a database connection previously passed
375            to AddDBConnection().
376            """
377            store = postgisdb.PostGISShapeStore(db, tablename,
378                                                id_column = id_column,
379                                                geometry_column = geometry_column)
380            self._add_shapestore(store)
381            return store
382    
383      def Destroy(self):      def Destroy(self):
384          for map in self.maps:          for map in self.maps:
385              map.Destroy()              map.Destroy()
386          self.maps = []          self.maps = []
387          self.tables = []          self.tables = []
388          Publisher.Destroy(self)          Modifiable.Destroy(self)
389    
390            # Close the transient DB explicitly so that it removes any
391            # journal files from the temporary directory
392            if self.transient_db is not None:
393                self.transient_db.close()
394    
395      def forward(self, *args):      def forward(self, *args):
396          """Reissue events.          """Reissue events.
# Line 159  class Session(TitledObject, Modifiable): Line 427  class Session(TitledObject, Modifiable):
427      def TreeInfo(self):      def TreeInfo(self):
428          items = []          items = []
429          if self.filename is None:          if self.filename is None:
430              items.append("Filename:")              items.append(_("Filename:"))
431          else:          else:
432              items.append("Filename: %s" % self.filename)              items.append(_("Filename: %s") % self.filename)
433    
434          if self.WasModified():          if self.WasModified():
435              items.append("Modified")              items.append(_("Modified"))
436          else:          else:
437              items.append("Unmodified")              items.append(_("Unmodified"))
438    
439          items.extend(self.maps)          items.extend(self.maps)
440          items.extend(self.extensions)          items.extend(self.extensions)
441    
442          return ("Session: %s" % self.title, items)          return (_("Session: %s") % self.title, items)
443    
444    
445  def create_empty_session():  def create_empty_session():
446      """Return an empty session useful as a starting point"""      """Return an empty session useful as a starting point"""
447      import os      import os
448      session = Session('unnamed session')      session = Session(_('unnamed session'))
449      session.SetFilename(None)      session.SetFilename(None)
450      session.AddMap(Map('unnamed map'))      session.AddMap(Map(_('unnamed map')))
451      session.UnsetModified()      session.UnsetModified()
452      return session      return session
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