--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/lib/django/db/utils.py	Tue May 25 02:43:45 2010 +0200
@@ -0,0 +1,161 @@
+import inspect
+import os
+
+from django.conf import settings
+from django.core.exceptions import ImproperlyConfigured
+from django.utils.importlib import import_module
+
+DEFAULT_DB_ALIAS = 'default'
+
+# Define some exceptions that mirror the PEP249 interface.
+# We will rethrow any backend-specific errors using these
+# common wrappers
+class DatabaseError(Exception):
+    pass
+
+class IntegrityError(DatabaseError):
+    pass
+
+
+def load_backend(backend_name):
+    try:
+        module = import_module('.base', 'django.db.backends.%s' % backend_name)
+        import warnings
+        warnings.warn(
+            "Short names for DATABASE_ENGINE are deprecated; prepend with 'django.db.backends.'",
+            PendingDeprecationWarning
+        )
+        return module
+    except ImportError, e:
+        # Look for a fully qualified database backend name
+        try:
+            return import_module('.base', backend_name)
+        except ImportError, e_user:
+            # The database backend wasn't found. Display a helpful error message
+            # listing all possible (built-in) database backends.
+            backend_dir = os.path.join(os.path.dirname(__file__), 'backends')
+            try:
+                available_backends = [f for f in os.listdir(backend_dir)
+                        if os.path.isdir(os.path.join(backend_dir, f))
+                        and not f.startswith('.')]
+            except EnvironmentError:
+                available_backends = []
+            available_backends.sort()
+            if backend_name not in available_backends:
+                error_msg = ("%r isn't an available database backend. \n" +
+                    "Try using django.db.backends.XXX, where XXX is one of:\n    %s\n" +
+                    "Error was: %s") % \
+                    (backend_name, ", ".join(map(repr, available_backends)), e_user)
+                raise ImproperlyConfigured(error_msg)
+            else:
+                raise # If there's some other error, this must be an error in Django itself.
+
+
+class ConnectionDoesNotExist(Exception):
+    pass
+
+
+class ConnectionHandler(object):
+    def __init__(self, databases):
+        self.databases = databases
+        self._connections = {}
+
+    def ensure_defaults(self, alias):
+        """
+        Puts the defaults into the settings dictionary for a given connection
+        where no settings is provided.
+        """
+        try:
+            conn = self.databases[alias]
+        except KeyError:
+            raise ConnectionDoesNotExist("The connection %s doesn't exist" % alias)
+
+        conn.setdefault('ENGINE', 'django.db.backends.dummy')
+        if conn['ENGINE'] == 'django.db.backends.' or not conn['ENGINE']:
+            conn['ENGINE'] = 'django.db.backends.dummy'
+        conn.setdefault('OPTIONS', {})
+        conn.setdefault('TEST_CHARSET', None)
+        conn.setdefault('TEST_COLLATION', None)
+        conn.setdefault('TEST_NAME', None)
+        conn.setdefault('TEST_MIRROR', None)
+        conn.setdefault('TIME_ZONE', settings.TIME_ZONE)
+        for setting in ('NAME', 'USER', 'PASSWORD', 'HOST', 'PORT'):
+            conn.setdefault(setting, '')
+
+    def __getitem__(self, alias):
+        if alias in self._connections:
+            return self._connections[alias]
+
+        self.ensure_defaults(alias)
+        db = self.databases[alias]
+        backend = load_backend(db['ENGINE'])
+        conn = backend.DatabaseWrapper(db, alias)
+        self._connections[alias] = conn
+        return conn
+
+    def __iter__(self):
+        return iter(self.databases)
+
+    def all(self):
+        return [self[alias] for alias in self]
+
+
+class ConnectionRouter(object):
+    def __init__(self, routers):
+        self.routers = []
+        for r in routers:
+            if isinstance(r, basestring):
+                try:
+                    module_name, klass_name = r.rsplit('.', 1)
+                    module = import_module(module_name)
+                except ImportError, e:
+                    raise ImproperlyConfigured('Error importing database router %s: "%s"' % (klass_name, e))
+                try:
+                    router = getattr(module, klass_name)()
+                except AttributeError:
+                    raise ImproperlyConfigured('Module "%s" does not define a database router name "%s"' % (module, klass_name))
+            else:
+                router = r
+            self.routers.append(router)
+
+    def _router_func(action):
+        def _route_db(self, model, **hints):
+            chosen_db = None
+            for router in self.routers:
+                try:
+                    chosen_db = getattr(router, action)(model, **hints)
+                    if chosen_db:
+                        return chosen_db
+                except AttributeError:
+                    # If the router doesn't have a method, skip to the next one.
+                    pass
+            try:
+                return hints['instance']._state.db or DEFAULT_DB_ALIAS
+            except KeyError:
+                return DEFAULT_DB_ALIAS
+        return _route_db
+
+    db_for_read = _router_func('db_for_read')
+    db_for_write = _router_func('db_for_write')
+
+    def allow_relation(self, obj1, obj2, **hints):
+        for router in self.routers:
+            try:
+                allow = router.allow_relation(obj1, obj2, **hints)
+                if allow is not None:
+                    return allow
+            except AttributeError:
+                # If the router doesn't have a method, skip to the next one.
+                pass
+        return obj1._state.db == obj2._state.db
+
+    def allow_syncdb(self, db, model):
+        for router in self.routers:
+            try:
+                allow = router.allow_syncdb(db, model)
+                if allow is not None:
+                    return allow
+            except AttributeError:
+                # If the router doesn't have a method, skip to the next one.
+                pass
+        return True