Thuban/Model/session.py

# Copyright (c) 2001, 2002, 2003 by Intevation GmbH
# Authors:
# Bernhard Herzog <[email protected]>
# Jan-Oliver Wagner <[email protected]>
#
# This program is free software under the GPL (>=v2)
# Read the file COPYING coming with Thuban for details.

__version__ = "$Revision$"

import os
from tempfile import mktemp
import weakref

from messages import MAPS_CHANGED, EXTENSIONS_CHANGED, FILENAME_CHANGED, \
     MAP_LAYERS_CHANGED, MAP_PROJECTION_CHANGED, \
     LAYER_CHANGED, LAYER_PROJECTION_CHANGED, LAYER_VISIBILITY_CHANGED,\
     EXTENSION_CHANGED, EXTENSION_OBJECTS_CHANGED, CHANGED

from Thuban import _

from base import TitledObject, Modifiable
from map import Map
from data import ShapefileStore
from table import DBFTable

from transientdb import TransientDatabase, AutoTransientTable

class AutoRemoveFile:

    """Remove a file once all references go away."""

    def __init__(self, filename, tempdir = None):
        """Initialize the AutoRemoveFile

        Parameters:
           filename -- The name of the file to remove in __del__
           tempdir -- Another object simple stored as an instance variable.

        As the name suggests the tempdir parameter is intended for a
        temporary directory the file might be located in. The intended
        use is that it's an instance of AutoRemoveDir.
        """
        self.filename = filename
        self.tempdir = tempdir

    def __del__(self, remove = os.remove):
        remove(self.filename)

class AutoRemoveDir:

    """Remove a directory once all references go away

    The intended use of this class together with AutoRemoveFile is for
    temporary directories and files containd therein. An AutoRemoveDir
    should be instantiated for the directory and passed as the tempdir
    parameter to every AutoRemoveFile instance created for files in the
    directory. An AutoRemoveFile shold be instantiated for every file
    created in the directory so that the directory is automatically
    removed once the last file is removed.
    """

    def __init__(self, filename):
        """Initialize the AutoRemoveDir

        The parameter is the name of the directory.
        """
        self.filename = filename

    def __del__(self, rmdir = os.rmdir):
        rmdir(self.filename)


# WeakKey dictionary mapping objects like the transient_db to
# AutoRemoveDir or AutoRemoveFile instances to make sure that the
# temporary files and the directory are deleted but not before the
# objects that use them go away.
auto_remover = weakref.WeakKeyDictionary()

class Session(TitledObject, Modifiable):

    """A complete session.

    A Session consists of arbitrary numbers of maps, tables and extensions

    Session objects send the following events:

        TITLE_CHANGED -- The title has changed. Parameters: the session.

        FILENAME_CHANGED -- The filename has changed. No parameters.

        MAPS_CHANGED -- Maps were added, removed.

        EXTENSIONS_CHANGED -- Extensions were added, removed.

        MAP_LAYERS_CHANGED -- Same as the map's event of the same name.
                          It's simply resent from the session to make
                          subscriptions easier.

        CHANGED -- Generic changed event. Parameters: the session. The
                   event is always issued when any other changed event
                   is issused. This is useful for code that needs to be
                   notified whenever something in the session has
                   changed but it's too cumbersome or error-prone to
                   subscribe to all the individual events.
    """

    # message channels that have to be forwarded from maps contained in
    # the session.
    forwarded_channels = (
        # generic channels
        CHANGED,

        # map specific channels
        MAP_PROJECTION_CHANGED,
        MAP_LAYERS_CHANGED,

        # layer channels forwarded by the map
        LAYER_PROJECTION_CHANGED,
        LAYER_CHANGED,
        LAYER_VISIBILITY_CHANGED,

        # channels forwarded by an extension
        EXTENSION_CHANGED,
        EXTENSION_OBJECTS_CHANGED)

    def __init__(self, title):
        TitledObject.__init__(self, title)
        Modifiable.__init__(self)
        self.filename = None
        self.maps = []
        self.tables = []
        self.shapestores = []
        self.extensions = []
        self.temp_dir = None
        self.transient_db = None

    def changed(self, channel = None, *args):
        """Like the inherited version but issue a CHANGED message as well.

        The CHANGED message is only issued if channel given is a
        different channel than CHANGED.
        """
        Modifiable.changed(self, channel, *args)
        if channel != CHANGED:
            self.issue(CHANGED, self)

    def SetFilename(self, filename):
        self.filename = filename
        self.changed(FILENAME_CHANGED)

    def Maps(self):
        return self.maps

    def HasMaps(self):
        return len(self.maps) > 0

    def AddMap(self, map):
        self.maps.append(map)
        for channel in self.forwarded_channels:
            map.Subscribe(channel, self.forward, channel)
        self.changed(MAPS_CHANGED)

    def RemoveMap(self, map):
        for channel in self.forwarded_channels:
            map.Unsubscribe(channel, self.forward, channel)
        self.maps.remove(map)
        self.changed(MAPS_CHANGED)
        map.Destroy()

    def Extensions(self):
        return self.extensions

    def HasExtensions(self):
        return len(self.extensions) > 0

    def AddExtension(self, extension):
        self.extensions.append(extension)
        for channel in self.forwarded_channels:
            extension.Subscribe(channel, self.forward, channel)
        self.changed(EXTENSIONS_CHANGED)

    def ShapeStores(self):
        """Return a list of all ShapeStore objects open in the session"""
        return [store() for store in self.shapestores]

    def _add_shapestore(self, store):
        """Internal: Add the shapestore to the list of shapestores"""
        self.shapestores.append(weakref.ref(store,
                                            self._clean_weak_store_refs))

    def _clean_weak_store_refs(self, weakref):
        """Internal: Remove the weakref from the shapestores list"""
        self.shapestores = [store for store in self.shapestores
                                  if store is not weakref]

    def Tables(self):
        """Return a list of all table objects open in the session

        The list includes all tables that are indirectly opened through
        shape stores and the tables that have been opened explicitly.
        """
        return self.tables + [store.Table() for store in self.ShapeStores()]

    def AddTable(self, table):
        """Add the table to the session

        All tables associated with the session that are not implicitly
        created by the OpenShapefile method (and maybe other Open*
        methods in the future) have to be passed to this method to make
        sure the session knows about it. The session keeps a reference
        to the table. Only tables managed by the session in this way
        should be used for layers contained in one of the session's
        maps.

        The table parameter may be any object implementing the table
        interface. If it's not already one of the transient tables
        instantiate an AutoTransientTable with it and use that instead
        of the original table (note that the AutoTransientTable keeps a
        reference to the original table).

        Return the table object actually used by the session.
        """
        if not hasattr(table, "transient_table"):
            transient_table = AutoTransientTable(self.TransientDB(), table)
        else:
            transient_table = table
        self.tables.append(transient_table)
        return transient_table

    def RemoveTable(self, table):
        """Remove the table from the session.

        The table object must be a table object previously returned by
        the AddTable method. If the table is not part of the session
        raise a ValueError.
        """
        tables = [t for t in self.tables if t is not table]
        if len(tables) == len(self.tables):
            raise ValueError
        self.tables = tables

    def OpenTableFile(self, filename):
        """Open the table file filename and return the table object.

        The filename argument must be the name of a DBF file.
        """
        return self.AddTable(DBFTable(filename))

    def temp_directory(self):
        """
        Return the name of the directory for session specific temporary files

        Create the directory if it doesn't exist yet.
        """
        if self.temp_dir is None:
            temp_dir = mktemp()
            os.mkdir(temp_dir, 0700)
            self.temp_dir = temp_dir
            self.temp_dir_remover = AutoRemoveDir(self.temp_dir)
        return self.temp_dir

    def OpenShapefile(self, filename):
        """Return a shapefile store object for the data in the given file"""
        store = ShapefileStore(self, filename)
        self._add_shapestore(store)
        return store

    def AddShapeStore(self, shapestore):
        """Add the shapestore to the session.

        The session only holds a weak reference to the shapestore, so it
        will automatically be removed from the session when the last
        reference goes away.
        """
        self._add_shapestore(shapestore)
        return shapestore

    def TransientDB(self):
        if self.transient_db is None:
            filename = os.path.join(self.temp_directory(), "transientdb")
            self.transient_db = TransientDatabase(filename)
            #print self.temp_dir_remover
            auto_remover[self.transient_db] = AutoRemoveFile(filename,
                                                        self.temp_dir_remover)
        return self.transient_db

    def Destroy(self):
        for map in self.maps:
            map.Destroy()
        self.maps = []
        self.tables = []
        Modifiable.Destroy(self)

        # Close the transient DB explicitly so that it removes any
        # journal files from the temporary directory
        if self.transient_db is not None:
            self.transient_db.close()

    def forward(self, *args):
        """Reissue events.

        If the channel the event is forwarded to is a changed-channel
        that is not the CHANGED channel issue CHANGED as well. An
        channel is considered to be a changed-channel if it's name ends
        with 'CHANGED'.
        """
        if len(args) > 1:
            args = (args[-1],) + args[:-1]
        apply(self.issue, args)
        channel = args[0]
        # It's a bit of a kludge to rely on the channel name for this.
        if channel.endswith("CHANGED") and channel != CHANGED:
            self.issue(CHANGED, self)

    def WasModified(self):
        """Return true if the session or one of the maps was modified"""
        if self.modified:
            return 1
        else:
            for map in self.maps:
                if map.WasModified():
                    return 1
        return 0

    def UnsetModified(self):
        """Unset the modified flag of the session and the maps"""
        Modifiable.UnsetModified(self)
        for map in self.maps:
            map.UnsetModified()

    def TreeInfo(self):
        items = []
        if self.filename is None:
            items.append(_("Filename:"))
        else:
            items.append(_("Filename: %s") % self.filename)

        if self.WasModified():
            items.append(_("Modified"))
        else:
            items.append(_("Unmodified"))

        items.extend(self.maps)
        items.extend(self.extensions)

        return (_("Session: %s") % self.title, items)


def create_empty_session():
    """Return an empty session useful as a starting point"""
    import os
    session = Session(_('unnamed session'))
    session.SetFilename(None)
    session.AddMap(Map(_('unnamed map')))
    session.UnsetModified()
    return session
1	bh	723	# Copyright (c) 2001, 2002, 2003 by Intevation GmbH
2	bh	6	# Authors:
3			# Bernhard Herzog <[email protected]>
4	jan	197	# Jan-Oliver Wagner <[email protected]>
5	bh	6	#
6			# This program is free software under the GPL (>=v2)
7			# Read the file COPYING coming with Thuban for details.
8
9			__version__ = "$Revision$"
10
11	bh	765	import os
12			from tempfile import mktemp
13			import weakref
14
15	jan	197	from messages import MAPS_CHANGED, EXTENSIONS_CHANGED, FILENAME_CHANGED, \
16	jonathan	548	MAP_LAYERS_CHANGED, MAP_PROJECTION_CHANGED, \
17	jonathan	582	LAYER_CHANGED, LAYER_PROJECTION_CHANGED, LAYER_VISIBILITY_CHANGED,\
18	bh	232	EXTENSION_CHANGED, EXTENSION_OBJECTS_CHANGED, CHANGED
19	bh	6
20	jan	374	from Thuban import _
21
22	bh	6	from base import TitledObject, Modifiable
23			from map import Map
24	bh	723	from data import ShapefileStore
25	bh	1036	from table import DBFTable
26	bh	6
27	bh	982	from transientdb import TransientDatabase, AutoTransientTable
28	bh	6
29	bh	765	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	bh	6	class Session(TitledObject, Modifiable):
81
82			"""A complete session.
83
84	jan	197	A Session consists of arbitrary numbers of maps, tables and extensions
85	bh	6
86			Session objects send the following events:
87
88			TITLE_CHANGED -- The title has changed. Parameters: the session.
89
90			FILENAME_CHANGED -- The filename has changed. No parameters.
91
92			MAPS_CHANGED -- Maps were added, removed.
93
94	jan	197	EXTENSIONS_CHANGED -- Extensions were added, removed.
95
96	jonathan	548	MAP_LAYERS_CHANGED -- Same as the map's event of the same name.
97	bh	6	It's simply resent from the session to make
98			subscriptions easier.
99	bh	232
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	bh	6	"""
107
108	bh	128	# message channels that have to be forwarded from maps contained in
109			# the session.
110			forwarded_channels = (
111	bh	318	# generic channels
112			CHANGED,
113
114	bh	128	# map specific channels
115			MAP_PROJECTION_CHANGED,
116	jonathan	548	MAP_LAYERS_CHANGED,
117	bh	128
118			# layer channels forwarded by the map
119			LAYER_PROJECTION_CHANGED,
120	jonathan	582	LAYER_CHANGED,
121	jan	197	LAYER_VISIBILITY_CHANGED,
122	bh	128
123	jan	197	# channels forwarded by an extension
124			EXTENSION_CHANGED,
125			EXTENSION_OBJECTS_CHANGED)
126
127	bh	6	def __init__(self, title):
128			TitledObject.__init__(self, title)
129			Modifiable.__init__(self)
130			self.filename = None
131			self.maps = []
132			self.tables = []
133	bh	851	self.shapestores = []
134	jan	197	self.extensions = []
135	bh	765	self.temp_dir = None
136			self.transient_db = None
137	bh	6
138	bh	232	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	bh	6	def SetFilename(self, filename):
149			self.filename = filename
150			self.changed(FILENAME_CHANGED)
151
152			def Maps(self):
153			return self.maps
154
155			def HasMaps(self):
156			return len(self.maps) > 0
157
158			def AddMap(self, map):
159			self.maps.append(map)
160	bh	128	for channel in self.forwarded_channels:
161	bh	6	map.Subscribe(channel, self.forward, channel)
162			self.changed(MAPS_CHANGED)
163
164	bh	241	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	jan	197	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	bh	851	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	bh	982	"""Return a list of all table objects open in the session
199	bh	851
200	bh	982	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	bh	987	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	bh	1036	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	bh	765	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	bh	723	def OpenShapefile(self, filename):
264			"""Return a shapefile store object for the data in the given file"""
265	bh	851	store = ShapefileStore(self, filename)
266			self._add_shapestore(store)
267			return store
268	bh	723
269	bh	1016	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	bh	765	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	bh	6	def Destroy(self):
289			for map in self.maps:
290			map.Destroy()
291			self.maps = []
292			self.tables = []
293	bh	250	Modifiable.Destroy(self)
294	bh	6
295	bh	778	# 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	bh	6	def forward(self, *args):
301	bh	232	"""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	bh	6	if len(args) > 1:
309			args = (args[-1],) + args[:-1]
310			apply(self.issue, args)
311	bh	232	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	bh	6
316			def WasModified(self):
317			"""Return true if the session or one of the maps was modified"""
318			if self.modified:
319			return 1
320			else:
321			for map in self.maps:
322			if map.WasModified():
323			return 1
324			return 0
325
326			def UnsetModified(self):
327			"""Unset the modified flag of the session and the maps"""
328			Modifiable.UnsetModified(self)
329			for map in self.maps:
330			map.UnsetModified()
331
332	bh	217	def TreeInfo(self):
333			items = []
334			if self.filename is None:
335	jan	374	items.append(_("Filename:"))
336	bh	217	else:
337	jan	374	items.append(_("Filename: %s") % self.filename)
338	bh	6
339	bh	217	if self.WasModified():
340	jan	374	items.append(_("Modified"))
341	bh	217	else:
342	jan	374	items.append(_("Unmodified"))
343	bh	6
344	bh	217	items.extend(self.maps)
345			items.extend(self.extensions)
346
347	jan	374	return (_("Session: %s") % self.title, items)
348	bh	217
349
350	bh	6	def create_empty_session():
351			"""Return an empty session useful as a starting point"""
352	jan	103	import os
353	jan	374	session = Session(_('unnamed session'))
354	jan	103	session.SetFilename(None)
355	jan	374	session.AddMap(Map(_('unnamed map')))
356	bh	56	session.UnsetModified()
357	bh	6	return session
Name	Value
svn:eol-style	native
svn:keywords	Author Date Id Revision