Merged Trevor's tree

1 files changed, 617 insertions, 0 deletions

diff --git a/libbe/storage/util/settings_object.py b/libbe/storage/util/settings_object.py
new file mode 100644
index 0000000..6e4da55
--- /dev/null
+++ b/libbe/storage/util/settings_object.py
@@ -0,0 +1,617 @@
+# Bugs Everywhere - a distributed bugtracker
+# Copyright (C) 2008-2010 Gianluca Montecchi <gian@grys.it>
+#                         W. Trevor King <wking@drexel.edu>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+"""Provides :class:`SavedSettingsObject` implementing settings-dict
+based property storage.
+
+See Also
+--------
+:mod:`libbe.storage.util.properties` : underlying property definitions
+"""
+
+import libbe
+from properties import Property, doc_property, local_property, \
+    defaulting_property, checked_property, fn_checked_property, \
+    cached_property, primed_property, change_hook_property, \
+    settings_property
+if libbe.TESTING == True:
+    import doctest
+    import unittest
+
+class _Token (object):
+    """`Control' value class for properties.
+
+    We want values that only mean something to the `settings_object`
+    module.
+    """
+    pass
+
+class UNPRIMED (_Token):
+    "Property has not been primed (loaded)."
+    pass
+
+class EMPTY (_Token):
+    """Property has been primed but has no user-set value, so use
+    default/generator value.
+    """
+    pass
+
+
+def prop_save_settings(self, old, new):
+    """The default action undertaken when a property changes.
+    """
+    if self.storage != None and self.storage.is_writeable():
+        self.save_settings()
+
+def prop_load_settings(self):
+    """The default action undertaken when an UNPRIMED property is
+    accessed.
+
+    Attempt to run `.load_settings()`, which calls
+    `._setup_saved_settings()` internally.  If `.storage` is
+    inaccessible, don't do anything.
+    """
+    if self.storage != None and self.storage.is_readable():
+        self.load_settings()
+
+# Some name-mangling routines for pretty printing setting names
+def setting_name_to_attr_name(self, name):
+    """Convert keys to the `.settings` dict into their associated
+    SavedSettingsObject attribute names.
+
+    Examples
+    --------
+
+    >>> print setting_name_to_attr_name(None,"User-id")
+    user_id
+
+    See Also
+    --------
+    attr_name_to_setting_name : inverse
+    """
+    return name.lower().replace('-', '_')
+
+def attr_name_to_setting_name(self, name):
+    """Convert SavedSettingsObject attribute names to `.settings` dict
+    keys.
+
+    Examples:
+
+    >>> print attr_name_to_setting_name(None, "user_id")
+    User-id
+
+    See Also
+    --------
+    setting_name_to_attr_name : inverse
+    """
+    return name.capitalize().replace('_', '-')
+
+
+def versioned_property(name, doc,
+                       default=None, generator=None,
+                       change_hook=prop_save_settings,
+                       mutable=False,
+                       primer=prop_load_settings,
+                       allowed=None, check_fn=None,
+                       settings_properties=[],
+                       required_saved_properties=[],
+                       require_save=False):
+    """Combine the common decorators in a single function.
+
+    Use zero or one (but not both) of default or generator, since a
+    working default will keep the generator from functioning.  Use the
+    default if you know what you want the default value to be at
+    'coding time'.  Use the generator if you can write a function to
+    determine a valid default at run time.  If both default and
+    generator are None, then the property will be a defaulting
+    property which defaults to None.
+
+    allowed and check_fn have a similar relationship, although you can
+    use both of these if you want.  allowed compares the proposed
+    value against a list determined at 'coding time' and check_fn
+    allows more flexible comparisons to take place at run time.
+
+    Set require_save to True if you want to save the default/generated
+    value for a property, to protect against future changes.  E.g., we
+    currently expect all comments to be 'text/plain' but in the future
+    we may want to default to 'text/html'.  If we don't want the old
+    comments to be interpreted as 'text/html', we would require that
+    the content type be saved.
+
+    change_hook, primer, settings_properties, and
+    required_saved_properties are only options to get their defaults
+    into our local scope.  Don't mess with them.
+
+    Set mutable=True if:
+
+    * default is a mutable
+    * your generator function may return mutables
+    * you set change_hook and might have mutable property values
+
+    See the docstrings in `libbe.properties` for details on how each of
+    these cases are handled.
+
+    The value stored in `.settings[name]` will be
+
+    * no value (or UNPRIMED) if the property has been neither set,
+      nor loaded as blank.
+    * EMPTY if the value has been loaded as blank.
+    * some value if the property has been either loaded or set.
+    """
+    settings_properties.append(name)
+    if require_save == True:
+        required_saved_properties.append(name)
+    def decorator(funcs):
+        fulldoc = doc
+        if default != None or generator == None:
+            defaulting  = defaulting_property(default=default, null=EMPTY,
+                                              mutable_default=mutable)
+            fulldoc += "\n\nThis property defaults to %s." % default
+        if generator != None:
+            cached = cached_property(generator=generator, initVal=EMPTY,
+                                     mutable=mutable)
+            fulldoc += "\n\nThis property is generated with %s." % generator
+        if check_fn != None:
+            fn_checked = fn_checked_property(value_allowed_fn=check_fn)
+            fulldoc += "\n\nThis property is checked with %s." % check_fn
+        if allowed != None:
+            checked = checked_property(allowed=allowed)
+            fulldoc += "\n\nThe allowed values for this property are: %s." \
+                       % (', '.join(allowed))
+        hooked      = change_hook_property(hook=change_hook, mutable=mutable,
+                                           default=EMPTY)
+        primed      = primed_property(primer=primer, initVal=UNPRIMED,
+                                      unprimeableVal=EMPTY)
+        settings    = settings_property(name=name, null=UNPRIMED)
+        docp        = doc_property(doc=fulldoc)
+        deco = hooked(primed(settings(docp(funcs))))
+        if default != None or generator == None:
+            deco = defaulting(deco)
+        if generator != None:
+            deco = cached(deco)
+        if check_fn != None:
+            deco = fn_checked(deco)
+        if allowed != None:
+            deco = checked(deco)
+        return Property(deco)
+    return decorator
+
+class SavedSettingsObject(object):
+    """Setup a framework for lazy saving and loading of `.settings`
+    properties.
+
+    This is useful for BE objects with saved properties
+    (e.g. :class:`~libbe.bugdir.BugDir`, :class:`~libbe.bug.Bug`,
+    :class:`~libbe.comment.Comment`).  For example usage, consider the
+    unittests at the end of the module.
+
+    See Also
+    --------
+    versioned_property, prop_save_settings, prop_load_settings
+    setting_name_to_attr_name, attr_name_to_setting_name
+    """
+    # Keep a list of properties that may be stored in the .settings dict.
+    #settings_properties = []
+
+    # A list of properties that we save to disk, even if they were
+    # never set (in which case we save the default value).  This
+    # protects against future changes in default values.
+    #required_saved_properties = []
+
+    _setting_name_to_attr_name = setting_name_to_attr_name
+    _attr_name_to_setting_name = attr_name_to_setting_name
+
+    def __init__(self):
+        self.storage = None
+        self.settings = {}
+
+    def load_settings(self):
+        """Load the settings from disk."""
+        # Override.  Must call ._setup_saved_settings({}) with
+        # from-storage settings.
+        self._setup_saved_settings({})
+
+    def _setup_saved_settings(self, settings=None):
+        """
+        Sets up a settings dict loaded from storage.  Fills in
+        all missing settings entries with EMPTY.
+        """
+        if settings == None:
+            settings = {}
+        for property in self.settings_properties:
+            if property not in self.settings \
+                    or self.settings[property] == UNPRIMED:
+                if property in settings:
+                    self.settings[property] = settings[property]
+                else:
+                    self.settings[property] = EMPTY
+
+    def save_settings(self):
+        """Save the settings to disk."""
+        # Override.  Should save the dict output of ._get_saved_settings()
+        settings = self._get_saved_settings()
+        pass # write settings to disk....
+
+    def _get_saved_settings(self):
+        """
+        In order to avoid overwriting unread on-disk data, make sure
+        we've loaded anything sitting on the disk.  In the current
+        implementation, all the settings are stored in a single file,
+        so we need to load _all_ the saved settings.  Another approach
+        would be per-setting saves, in which case you could skip this
+        step, since any setting changes would have forced that setting
+        load already.
+        """
+        settings = {}
+        for k in self.settings_properties: # force full load
+            if not k in self.settings or self.settings[k] == UNPRIMED:
+                value = getattr(
+                    self, self._setting_name_to_attr_name(k))
+        for k in self.settings_properties:
+            if k in self.settings and self.settings[k] != EMPTY:
+                settings[k] = self.settings[k]
+            elif k in self.required_saved_properties:
+                settings[k] = getattr(
+                    self, self._setting_name_to_attr_name(k))
+        return settings
+
+    def clear_cached_setting(self, setting=None):
+        "If setting=None, clear *all* cached settings"
+        if setting != None:
+            if hasattr(self, "_%s_cached_value" % setting):
+                delattr(self, "_%s_cached_value" % setting)
+        else:
+            for setting in settings_properties:
+                self.clear_cached_setting(setting)
+
+
+if libbe.TESTING == True:
+    import copy
+
+    class TestStorage (list):
+        def __init__(self):
+            list.__init__(self)
+            self.readable = True
+            self.writeable = True
+        def is_readable(self):
+            return self.readable
+        def is_writeable(self):
+            return self.writeable
+        
+    class TestObject (SavedSettingsObject):
+        def load_settings(self):
+            self.load_count += 1
+            if len(self.storage) == 0:
+                settings = {}
+            else:
+                settings = copy.deepcopy(self.storage[-1])
+            self._setup_saved_settings(settings)
+        def save_settings(self):
+            settings = self._get_saved_settings()
+            self.storage.append(copy.deepcopy(settings))
+        def __init__(self):
+            SavedSettingsObject.__init__(self)
+            self.load_count = 0
+            self.storage = TestStorage()
+
+    class SavedSettingsObjectTests(unittest.TestCase):
+        def testSimplePropertyDoc(self):
+            """Testing a minimal versioned property docstring"""
+            class Test (TestObject):
+                settings_properties = []
+                required_saved_properties = []
+                @versioned_property(
+                    name="Content-type",
+                    doc="A test property",
+                    settings_properties=settings_properties,
+                    required_saved_properties=required_saved_properties)
+                def content_type(): return {}
+            expected = "A test property\n\nThis property defaults to None."
+            self.failUnless(Test.content_type.__doc__ == expected,
+                            Test.content_type.__doc__)
+        def testSimplePropertyFromMemory(self):
+            """Testing a minimal versioned property from memory"""
+            class Test (TestObject):
+                settings_properties = []
+                required_saved_properties = []
+                @versioned_property(
+                    name="Content-type",
+                    doc="A test property",
+                    settings_properties=settings_properties,
+                    required_saved_properties=required_saved_properties)
+                def content_type(): return {}
+            t = Test()
+            self.failUnless(len(t.settings) == 0, len(t.settings))
+            # accessing t.content_type triggers the priming, but
+            # t.storage.is_readable() == False, so nothing happens.
+            t.storage.readable = False
+            self.failUnless(t.content_type == None, t.content_type)
+            self.failUnless(t.settings == {}, t.settings)
+            self.failUnless(len(t.settings) == 0, len(t.settings))
+            self.failUnless(t.content_type == None, t.content_type)
+            # accessing t.content_type triggers the priming again, and
+            # now that t.storage.is_readable() == True, this fills out
+            # t.settings with EMPTY data.  At this point there should
+            # be one load and no saves.
+            t.storage.readable = True
+            self.failUnless(t.content_type == None, t.content_type)
+            self.failUnless(len(t.settings) == 1, len(t.settings))
+            self.failUnless(t.settings["Content-type"] == EMPTY,
+                            t.settings["Content-type"])
+            self.failUnless(t.content_type == None, t.content_type)
+            self.failUnless(t.load_count == 1, t.load_count)
+            self.failUnless(len(t.storage) == 0, len(t.storage))
+            # an explicit call to load settings forces a reload,
+            # but nothing else changes.
+            t.load_settings()
+            self.failUnless(len(t.settings) == 1, len(t.settings))
+            self.failUnless(t.settings["Content-type"] == EMPTY,
+                            t.settings["Content-type"])
+            self.failUnless(t.content_type == None, t.content_type)
+            self.failUnless(t.load_count == 2, t.load_count)
+            self.failUnless(len(t.storage) == 0, len(t.storage))
+            # now we set a value
+            t.content_type = 5
+            self.failUnless(t.settings["Content-type"] == 5,
+                            t.settings["Content-type"])
+            self.failUnless(t.load_count == 2, t.load_count)
+            self.failUnless(len(t.storage) == 1, len(t.storage))
+            self.failUnless(t.storage == [{'Content-type':5}], t.storage)
+            # getting its value changes nothing
+            self.failUnless(t.content_type == 5, t.content_type)
+            self.failUnless(t.settings["Content-type"] == 5,
+                            t.settings["Content-type"])
+            self.failUnless(t.load_count == 2, t.load_count)
+            self.failUnless(len(t.storage) == 1, len(t.storage))
+            self.failUnless(t.storage == [{'Content-type':5}], t.storage)
+            # now we set another value
+            t.content_type = "text/plain"
+            self.failUnless(t.content_type == "text/plain", t.content_type)
+            self.failUnless(t.settings["Content-type"] == "text/plain",
+                            t.settings["Content-type"])
+            self.failUnless(t.load_count == 2, t.load_count)
+            self.failUnless(len(t.storage) == 2, len(t.storage))
+            self.failUnless(t.storage == [{'Content-type':5},
+                                          {'Content-type':'text/plain'}],
+                            t.storage)
+            # t._get_saved_settings() returns a dict of required or
+            # non-default values.
+            self.failUnless(t._get_saved_settings() == \
+                                {"Content-type":"text/plain"},
+                            t._get_saved_settings())
+            # now we clear to the post-primed value
+            t.content_type = EMPTY
+            self.failUnless(t.settings["Content-type"] == EMPTY,
+                            t.settings["Content-type"])
+            self.failUnless(t.content_type == None, t.content_type)
+            self.failUnless(len(t.settings) == 1, len(t.settings))
+            self.failUnless(t.settings["Content-type"] == EMPTY,
+                            t.settings["Content-type"])
+            self.failUnless(t._get_saved_settings() == {},
+                            t._get_saved_settings())
+            self.failUnless(t.storage == [{'Content-type':5},
+                                          {'Content-type':'text/plain'},
+                                          {}],
+                            t.storage)
+        def testSimplePropertyFromStorage(self):
+            """Testing a minimal versioned property from storage"""
+            class Test (TestObject):
+                settings_properties = []
+                required_saved_properties = []
+                @versioned_property(
+                    name="prop-a",
+                    doc="A test property",
+                    settings_properties=settings_properties,
+                    required_saved_properties=required_saved_properties)
+                def prop_a(): return {}
+                @versioned_property(
+                    name="prop-b",
+                    doc="Another test property",
+                    settings_properties=settings_properties,
+                    required_saved_properties=required_saved_properties)
+                def prop_b(): return {}
+            t = Test()
+            t.storage.append({'prop-a':'saved'})
+            # setting prop-b forces a load (to check for changes),
+            # which also pulls in prop-a.
+            t.prop_b = 'new-b'
+            settings = {'prop-b':'new-b', 'prop-a':'saved'}
+            self.failUnless(t.settings == settings, t.settings)
+            self.failUnless(t._get_saved_settings() == settings,
+                            t._get_saved_settings())
+            # test that _get_saved_settings() works even when settings
+            # were _not_ loaded beforehand
+            t = Test()
+            t.storage.append({'prop-a':'saved'})
+            settings ={'prop-a':'saved'}
+            self.failUnless(t.settings == {}, t.settings)
+            self.failUnless(t._get_saved_settings() == settings,
+                            t._get_saved_settings())
+        def testSimplePropertySetStorageSave(self):
+            """Set a property, then attach storage and save"""
+            class Test (TestObject):
+                settings_properties = []
+                required_saved_properties = []
+                @versioned_property(
+                    name="prop-a",
+                    doc="A test property",
+                    settings_properties=settings_properties,
+                    required_saved_properties=required_saved_properties)
+                def prop_a(): return {}
+                @versioned_property(
+                    name="prop-b",
+                    doc="Another test property",
+                    settings_properties=settings_properties,
+                    required_saved_properties=required_saved_properties)
+                def prop_b(): return {}
+            t = Test()
+            storage = t.storage
+            t.storage = None
+            t.prop_a = 'text/html'
+            t.storage = storage
+            t.save_settings()
+            self.failUnless(t.prop_a == 'text/html', t.prop_a)
+            self.failUnless(t.settings == {'prop-a':'text/html',
+                                           'prop-b':EMPTY},
+                            t.settings)
+            self.failUnless(t.load_count == 1, t.load_count)
+            self.failUnless(len(t.storage) == 1, len(t.storage))
+            self.failUnless(t.storage == [{'prop-a':'text/html'}],
+                            t.storage)
+        def testDefaultingProperty(self):
+            """Testing a defaulting versioned property"""
+            class Test (TestObject):
+                settings_properties = []
+                required_saved_properties = []
+                @versioned_property(
+                    name="Content-type",
+                    doc="A test property",
+                    default="text/plain",
+                    settings_properties=settings_properties,
+                    required_saved_properties=required_saved_properties)
+                def content_type(): return {}
+            t = Test()
+            self.failUnless(t.settings == {}, t.settings)
+            self.failUnless(t.content_type == "text/plain", t.content_type)
+            self.failUnless(t.settings == {"Content-type":EMPTY},
+                            t.settings)
+            self.failUnless(t.load_count == 1, t.load_count)
+            self.failUnless(len(t.storage) == 0, len(t.storage))
+            self.failUnless(t._get_saved_settings() == {},
+                            t._get_saved_settings())
+            t.content_type = "text/html"
+            self.failUnless(t.content_type == "text/html",
+                            t.content_type)
+            self.failUnless(t.settings == {"Content-type":"text/html"},
+                            t.settings)
+            self.failUnless(t.load_count == 1, t.load_count)
+            self.failUnless(len(t.storage) == 1, len(t.storage))
+            self.failUnless(t.storage == [{'Content-type':'text/html'}],
+                            t.storage)
+            self.failUnless(t._get_saved_settings() == \
+                                {"Content-type":"text/html"},
+                            t._get_saved_settings())
+        def testRequiredDefaultingProperty(self):
+            """Testing a required defaulting versioned property"""
+            class Test (TestObject):
+                settings_properties = []
+                required_saved_properties = []
+                @versioned_property(
+                    name="Content-type",
+                    doc="A test property",
+                    default="text/plain",
+                    settings_properties=settings_properties,
+                    required_saved_properties=required_saved_properties,
+                    require_save=True)
+                def content_type(): return {}
+            t = Test()
+            self.failUnless(t.settings == {}, t.settings)
+            self.failUnless(t.content_type == "text/plain", t.content_type)
+            self.failUnless(t.settings == {"Content-type":EMPTY},
+                            t.settings)
+            self.failUnless(t.load_count == 1, t.load_count)
+            self.failUnless(len(t.storage) == 0, len(t.storage))
+            self.failUnless(t._get_saved_settings() == \
+                                {"Content-type":"text/plain"},
+                            t._get_saved_settings())
+            t.content_type = "text/html"
+            self.failUnless(t.content_type == "text/html",
+                            t.content_type)
+            self.failUnless(t.settings == {"Content-type":"text/html"},
+                            t.settings)
+            self.failUnless(t.load_count == 1, t.load_count)
+            self.failUnless(len(t.storage) == 1, len(t.storage))
+            self.failUnless(t.storage == [{'Content-type':'text/html'}],
+                            t.storage)
+            self.failUnless(t._get_saved_settings() == \
+                                {"Content-type":"text/html"},
+                            t._get_saved_settings())
+        def testClassVersionedPropertyDefinition(self):
+            """Testing a class-specific _versioned property decorator"""
+            class Test (TestObject):
+                settings_properties = []
+                required_saved_properties = []
+                def _versioned_property(
+                        settings_properties=settings_properties,
+                        required_saved_properties=required_saved_properties,
+                        **kwargs):
+                    if "settings_properties" not in kwargs:
+                        kwargs["settings_properties"] = settings_properties
+                    if "required_saved_properties" not in kwargs:
+                        kwargs["required_saved_properties"] = \
+                            required_saved_properties
+                    return versioned_property(**kwargs)
+                @_versioned_property(name="Content-type",
+                                     doc="A test property",
+                                     default="text/plain",
+                                     require_save=True)
+                def content_type(): return {}
+            t = Test()
+            self.failUnless(t._get_saved_settings() == \
+                                {"Content-type":"text/plain"},
+                            t._get_saved_settings())
+            self.failUnless(t.load_count == 1, t.load_count)
+            self.failUnless(len(t.storage) == 0, len(t.storage))
+            t.content_type = "text/html"
+            self.failUnless(t._get_saved_settings() == \
+                                {"Content-type":"text/html"},
+                            t._get_saved_settings())
+            self.failUnless(t.load_count == 1, t.load_count)
+            self.failUnless(len(t.storage) == 1, len(t.storage))
+            self.failUnless(t.storage == [{'Content-type':'text/html'}],
+                            t.storage)
+        def testMutableChangeHookedProperty(self):
+            """Testing a mutable change-hooked property"""
+            class Test (TestObject):
+                settings_properties = []
+                required_saved_properties = []
+                @versioned_property(
+                    name="List-type",
+                    doc="A test property",
+                    mutable=True,
+                    change_hook=prop_save_settings,
+                    settings_properties=settings_properties,
+                    required_saved_properties=required_saved_properties)
+                def list_type(): return {}
+            t = Test()
+            self.failUnless(len(t.storage) == 0, len(t.storage))
+            self.failUnless(t.list_type == None, t.list_type)
+            self.failUnless(len(t.storage) == 0, len(t.storage))
+            self.failUnless(t.settings["List-type"]==EMPTY,
+                            t.settings["List-type"])
+            t.list_type = []
+            self.failUnless(t.settings["List-type"] == [],
+                            t.settings["List-type"])
+            self.failUnless(len(t.storage) == 1, len(t.storage))
+            self.failUnless(t.storage == [{'List-type':[]}],
+                            t.storage)
+            t.list_type.append(5) # external modification not detected yet
+            self.failUnless(len(t.storage) == 1, len(t.storage))
+            self.failUnless(t.storage == [{'List-type':[]}],
+                            t.storage)
+            self.failUnless(t.settings["List-type"] == [5],
+                            t.settings["List-type"])
+            self.failUnless(t.list_type == [5], t.list_type)# get triggers save
+            self.failUnless(len(t.storage) == 2, len(t.storage))
+            self.failUnless(t.storage == [{'List-type':[]},
+                                          {'List-type':[5]}],
+                            t.storage)
+
+    unitsuite = unittest.TestLoader().loadTestsFromTestCase( \
+        SavedSettingsObjectTests)
+    suite = unittest.TestSuite([unitsuite, doctest.DocTestSuite()])