/[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 778 by bh, Tue Apr 29 14:54:17 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
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.extensions = []
133            self.temp_dir = None
134            self.transient_db = None
135    
136        def changed(self, channel = None, *args):
137            """Like the inherited version but issue a CHANGED message as well.
138    
139            The CHANGED message is only issued if channel given is a
140            different channel than CHANGED.
141            """
142            Modifiable.changed(self, channel, *args)
143            if channel != CHANGED:
144                self.issue(CHANGED, self)
145    
146      def SetFilename(self, filename):      def SetFilename(self, filename):
147          self.filename = filename          self.filename = filename
# Line 55  class Session(TitledObject, Modifiable): Line 155  class Session(TitledObject, Modifiable):
155    
156      def AddMap(self, map):      def AddMap(self, map):
157          self.maps.append(map)          self.maps.append(map)
158          for channel in (LAYERS_CHANGED, MAP_PROJECTION_CHANGED,          for channel in self.forwarded_channels:
                         LAYER_LEGEND_CHANGED):  
159              map.Subscribe(channel, self.forward, channel)              map.Subscribe(channel, self.forward, channel)
160          self.changed(MAPS_CHANGED)          self.changed(MAPS_CHANGED)
161    
162        def RemoveMap(self, map):
163            for channel in self.forwarded_channels:
164                map.Unsubscribe(channel, self.forward, channel)
165            self.maps.remove(map)
166            self.changed(MAPS_CHANGED)
167            map.Destroy()
168    
169        def Extensions(self):
170            return self.extensions
171    
172        def HasExtensions(self):
173            return len(self.extensions) > 0
174    
175        def AddExtension(self, extension):
176            self.extensions.append(extension)
177            for channel in self.forwarded_channels:
178                extension.Subscribe(channel, self.forward, channel)
179            self.changed(EXTENSIONS_CHANGED)
180    
181        def temp_directory(self):
182            """
183            Return the name of the directory for session specific temporary files
184    
185            Create the directory if it doesn't exist yet.
186            """
187            if self.temp_dir is None:
188                temp_dir = mktemp()
189                os.mkdir(temp_dir, 0700)
190                self.temp_dir = temp_dir
191                self.temp_dir_remover = AutoRemoveDir(self.temp_dir)
192            return self.temp_dir
193    
194        def OpenShapefile(self, filename):
195            """Return a shapefile store object for the data in the given file"""
196            return ShapefileStore(self, filename)
197    
198        def TransientDB(self):
199            if self.transient_db is None:
200                filename = os.path.join(self.temp_directory(), "transientdb")
201                self.transient_db = TransientDatabase(filename)
202                #print self.temp_dir_remover
203                auto_remover[self.transient_db] = AutoRemoveFile(filename,
204                                                            self.temp_dir_remover)
205            return self.transient_db
206    
207      def Destroy(self):      def Destroy(self):
208          for map in self.maps:          for map in self.maps:
209              map.Destroy()              map.Destroy()
210          self.maps = []          self.maps = []
211          self.tables = []          self.tables = []
212          Publisher.Destroy(self)          Modifiable.Destroy(self)
213    
214            # Close the transient DB explicitly so that it removes any
215            # journal files from the temporary directory
216            if self.transient_db is not None:
217                self.transient_db.close()
218    
219      def forward(self, *args):      def forward(self, *args):
220          """Reissue events"""          """Reissue events.
221    
222            If the channel the event is forwarded to is a changed-channel
223            that is not the CHANGED channel issue CHANGED as well. An
224            channel is considered to be a changed-channel if it's name ends
225            with 'CHANGED'.
226            """
227          if len(args) > 1:          if len(args) > 1:
228              args = (args[-1],) + args[:-1]              args = (args[-1],) + args[:-1]
229          apply(self.issue, args)          apply(self.issue, args)
230            channel = args[0]
231            # It's a bit of a kludge to rely on the channel name for this.
232            if channel.endswith("CHANGED") and channel != CHANGED:
233                self.issue(CHANGED, self)
234    
235      def WasModified(self):      def WasModified(self):
236          """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 248  class Session(TitledObject, Modifiable):
248          for map in self.maps:          for map in self.maps:
249              map.UnsetModified()              map.UnsetModified()
250    
251        def TreeInfo(self):
252            items = []
253            if self.filename is None:
254                items.append(_("Filename:"))
255            else:
256                items.append(_("Filename: %s") % self.filename)
257    
258            if self.WasModified():
259                items.append(_("Modified"))
260            else:
261                items.append(_("Unmodified"))
262    
263            items.extend(self.maps)
264            items.extend(self.extensions)
265    
266            return (_("Session: %s") % self.title, items)
267    
268    
269  def create_empty_session():  def create_empty_session():
270      """Return an empty session useful as a starting point"""      """Return an empty session useful as a starting point"""
271      session = Session('unnamed session')      import os
272      session.SetFilename('unnamed.session')      session = Session(_('unnamed session'))
273      session.AddMap(Map('unnamed map'))      session.SetFilename(None)
274        session.AddMap(Map(_('unnamed map')))
275        session.UnsetModified()
276      return session      return session
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