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 transientdb import TransientDatabase

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.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 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"""
        return ShapefileStore(self, filename)

    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	6
26	bh	765	from transientdb import TransientDatabase
27	bh	6
28	bh	765	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	bh	6	class Session(TitledObject, Modifiable):
80
81			"""A complete session.
82
83	jan	197	A Session consists of arbitrary numbers of maps, tables and extensions
84	bh	6
85			Session objects send the following events:
86
87			TITLE_CHANGED -- The title has changed. Parameters: the session.
88
89			FILENAME_CHANGED -- The filename has changed. No parameters.
90
91			MAPS_CHANGED -- Maps were added, removed.
92
93	jan	197	EXTENSIONS_CHANGED -- Extensions were added, removed.
94
95	jonathan	548	MAP_LAYERS_CHANGED -- Same as the map's event of the same name.
96	bh	6	It's simply resent from the session to make
97			subscriptions easier.
98	bh	232
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	bh	6	"""
106
107	bh	128	# message channels that have to be forwarded from maps contained in
108			# the session.
109			forwarded_channels = (
110	bh	318	# generic channels
111			CHANGED,
112
113	bh	128	# map specific channels
114			MAP_PROJECTION_CHANGED,
115	jonathan	548	MAP_LAYERS_CHANGED,
116	bh	128
117			# layer channels forwarded by the map
118			LAYER_PROJECTION_CHANGED,
119	jonathan	582	LAYER_CHANGED,
120	jan	197	LAYER_VISIBILITY_CHANGED,
121	bh	128
122	jan	197	# channels forwarded by an extension
123			EXTENSION_CHANGED,
124			EXTENSION_OBJECTS_CHANGED)
125
126	bh	6	def __init__(self, title):
127			TitledObject.__init__(self, title)
128			Modifiable.__init__(self)
129			self.filename = None
130			self.maps = []
131			self.tables = []
132	jan	197	self.extensions = []
133	bh	765	self.temp_dir = None
134			self.transient_db = None
135	bh	6
136	bh	232	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	bh	6	def SetFilename(self, filename):
147			self.filename = filename
148			self.changed(FILENAME_CHANGED)
149
150			def Maps(self):
151			return self.maps
152
153			def HasMaps(self):
154			return len(self.maps) > 0
155
156			def AddMap(self, map):
157			self.maps.append(map)
158	bh	128	for channel in self.forwarded_channels:
159	bh	6	map.Subscribe(channel, self.forward, channel)
160			self.changed(MAPS_CHANGED)
161
162	bh	241	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	jan	197	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	bh	765	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	bh	723	def OpenShapefile(self, filename):
195			"""Return a shapefile store object for the data in the given file"""
196			return ShapefileStore(self, filename)
197
198	bh	765	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	bh	6	def Destroy(self):
208			for map in self.maps:
209			map.Destroy()
210			self.maps = []
211			self.tables = []
212	bh	250	Modifiable.Destroy(self)
213	bh	6
214	bh	778	# 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	bh	6	def forward(self, *args):
220	bh	232	"""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	bh	6	if len(args) > 1:
228			args = (args[-1],) + args[:-1]
229			apply(self.issue, args)
230	bh	232	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	bh	6
235			def WasModified(self):
236			"""Return true if the session or one of the maps was modified"""
237			if self.modified:
238			return 1
239			else:
240			for map in self.maps:
241			if map.WasModified():
242			return 1
243			return 0
244
245			def UnsetModified(self):
246			"""Unset the modified flag of the session and the maps"""
247			Modifiable.UnsetModified(self)
248			for map in self.maps:
249			map.UnsetModified()
250
251	bh	217	def TreeInfo(self):
252			items = []
253			if self.filename is None:
254	jan	374	items.append(_("Filename:"))
255	bh	217	else:
256	jan	374	items.append(_("Filename: %s") % self.filename)
257	bh	6
258	bh	217	if self.WasModified():
259	jan	374	items.append(_("Modified"))
260	bh	217	else:
261	jan	374	items.append(_("Unmodified"))
262	bh	6
263	bh	217	items.extend(self.maps)
264			items.extend(self.extensions)
265
266	jan	374	return (_("Session: %s") % self.title, items)
267	bh	217
268
269	bh	6	def create_empty_session():
270			"""Return an empty session useful as a starting point"""
271	jan	103	import os
272	jan	374	session = Session(_('unnamed session'))
273	jan	103	session.SetFilename(None)
274	jan	374	session.AddMap(Map(_('unnamed map')))
275	bh	56	session.UnsetModified()
276	bh	6	return session
Name	Value
svn:eol-style	native
svn:keywords	Author Date Id Revision