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)

    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	# Copyright (c) 2001, 2002, 2003 by Intevation GmbH
2	# Authors:
3	# Bernhard Herzog <[email protected]>
4	# Jan-Oliver Wagner <[email protected]>
5	#
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	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 Thuban import _
21
22	from base import TitledObject, Modifiable
23	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):
80
81	"""A complete session.
82
83	A Session consists of arbitrary numbers of maps, tables and extensions
84
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	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
97	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):
127	TitledObject.__init__(self, title)
128	Modifiable.__init__(self)
129	self.filename = None
130	self.maps = []
131	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):
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	for channel in self.forwarded_channels:
159	map.Subscribe(channel, self.forward, channel)
160	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):
208	for map in self.maps:
209	map.Destroy()
210	self.maps = []
211	self.tables = []
212	Modifiable.Destroy(self)
213
214	def forward(self, *args):
215	"""Reissue events.
216
217	If the channel the event is forwarded to is a changed-channel
218	that is not the CHANGED channel issue CHANGED as well. An
219	channel is considered to be a changed-channel if it's name ends
220	with 'CHANGED'.
221	"""
222	if len(args) > 1:
223	args = (args[-1],) + args[:-1]
224	apply(self.issue, args)
225	channel = args[0]
226	# It's a bit of a kludge to rely on the channel name for this.
227	if channel.endswith("CHANGED") and channel != CHANGED:
228	self.issue(CHANGED, self)
229
230	def WasModified(self):
231	"""Return true if the session or one of the maps was modified"""
232	if self.modified:
233	return 1
234	else:
235	for map in self.maps:
236	if map.WasModified():
237	return 1
238	return 0
239
240	def UnsetModified(self):
241	"""Unset the modified flag of the session and the maps"""
242	Modifiable.UnsetModified(self)
243	for map in self.maps:
244	map.UnsetModified()
245
246	def TreeInfo(self):
247	items = []
248	if self.filename is None:
249	items.append(_("Filename:"))
250	else:
251	items.append(_("Filename: %s") % self.filename)
252
253	if self.WasModified():
254	items.append(_("Modified"))
255	else:
256	items.append(_("Unmodified"))
257
258	items.extend(self.maps)
259	items.extend(self.extensions)
260
261	return (_("Session: %s") % self.title, items)
262
263
264	def create_empty_session():
265	"""Return an empty session useful as a starting point"""
266	import os
267	session = Session(_('unnamed session'))
268	session.SetFilename(None)
269	session.AddMap(Map(_('unnamed map')))
270	session.UnsetModified()
271	return session
Name	Value
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svn:keywords	Author Date Id Revision