move file based properties out of core

Signed-off-by: Steven Armstrong <steven@icarus.ethz.ch>

lib/cdist/util/property.py

@@ -0,0 +1,214 @@
+# -*- coding: utf-8 -*-
+#
+# 2010-2011 Steven Armstrong (steven-cdist at armstrong.cc)
+#
+# This file is part of cdist.
+#
+# cdist 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 3 of the License, or
+# (at your option) any later version.
+#
+# cdist 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 cdist. If not, see <http://www.gnu.org/licenses/>.
+#
+#
+
+import os
+import collections
+
+import cdist
+
+
+class AbsolutePathRequiredError(cdist.Error):
+    def __init__(self, path):
+        self.path = path
+
+    def __str__(self):
+        return 'Absolute path required, got: %s' % self.path
+
+
+class FileList(collections.MutableSequence):
+    """A list that stores it's state in a file.
+
+    """
+    def __init__(self, path, initial=None):
+        if not os.path.isabs(path):
+            raise AbsolutePathRequiredError(path)
+        self._path = path
+        if initial:
+            # delete existing file
+            os.unlink(self._path)
+            for i in initial:
+                self.append(i)
+
+    def __read(self):
+        lines = []
+        try:
+            with open(self._path) as fd:
+                for line in fd:
+                    lines.append(line.rstrip('\n'))
+        except EnvironmentError as e:
+            # error ignored
+            pass
+        return lines
+
+    def __write(self, lines):
+        try:
+            with open(self._path, 'w') as fd:
+                for line in lines:
+                    fd.write(str(line) + '\n')
+        except EnvironmentError as e:
+            # error ignored
+            raise
+
+    def __repr__(self):
+        return repr(list(self))
+
+    def __getitem__(self, index):
+        return self.__read()[index]
+        
+    def __setitem__(self, index, value):
+        lines = self.__read()
+        lines[index] = value
+        self.__write(lines)
+
+    def __delitem__(self, index):
+        lines = self.__read()
+        del lines[index]
+        self.__write(lines)
+
+    def __len__(self):
+        lines = self.__read()
+        return len(lines)
+
+    def insert(self, index, value):
+        lines = self.__read()
+        lines.insert(index, value)
+        self.__write(lines)
+
+    def sort(self):
+        lines = sorted(self)
+        self.__write(lines)
+
+
+class FileListProperty(FileList):
+    # Descriptor Protocol
+    def __get__(self, obj, objtype=None):
+        if obj is None:
+            return self.__class__
+        return self
+
+    def __set__(self, obj, value):
+        os.unlink(self._path)
+        for item in value:
+            self.append(item)
+
+    def __delete__(self, obj):
+        raise AttributeError("can't delete attribute")
+
+
+class DirectoryDict(collections.MutableMapping):
+    """A dict that stores it's state in a directory.
+
+    """
+    def __init__(self, path, dict=None, **kwargs):
+        if not os.path.isabs(path):
+            raise AbsolutePathRequiredError(path)
+        self._path = path
+        if dict is not None:
+            self.update(dict)
+        if len(kwargs):
+            self.update(kwargs)
+
+    def __repr__(self):
+        return repr(dict(self))
+
+    def __getitem__(self, key):
+        try:
+            with open(os.path.join(self._path, key), "r") as fd:
+                return fd.read().rstrip('\n')
+        except EnvironmentError:
+            raise KeyError(key)
+
+    def __setitem__(self, key, value):
+        with open(os.path.join(self._path, key), "w") as fd:
+            fd.write(str(value))        
+
+    def __delitem__(self, key):
+        os.remove(os.path.join(self._path, key))
+
+    def __iter__(self):
+        return iter(os.listdir(self._path))
+
+    def __len__(self):
+        return len(os.listdir(self._path))
+
+
+class DirectoryDictProperty(DirectoryDict):
+    # Descriptor Protocol
+    def __get__(self, obj, objtype=None):
+        if obj is None:
+            return self.__class__
+        return self
+
+    def __set__(self, obj, value):
+        for name in self.keys():
+            del self[name]
+        if value is not None:
+            self.update(value)
+
+    def __delete__(self, obj):
+        raise AttributeError("can't delete attribute")
+
+
+class FileBooleanProperty(object):
+    def __init__(self, path):
+        """
+        :param path: string or callable
+
+        Usage:
+
+        class Foo(object):
+            changed = FileBoolean(lambda obj: os.path.join(obj.absolute_path, 'changed'))
+            other_boolean = FileBoolean('/tmp/other_boolean')
+
+            def __init__(self):
+                self.absolute_path = '/tmp/foo_boolean'
+
+        """
+        self._path = path
+
+    def _get_path(self, *args, **kwargs):
+        path = self._path
+        if callable(path):
+            return path(*args, **kwargs)
+        if not os.path.isabs(path):
+            raise AbsolutePathRequiredError(path)
+        return path
+
+    # Descriptor Protocol
+    def __get__(self, obj, objtype=None):
+        if obj is None:
+            return self.__class__
+        path = self._get_path(obj)
+        return os.path.isfile(path)
+
+    def __set__(self, obj, value):
+        path = self._get_path(obj)
+        if value:
+            open(path, "w").close()
+        else:
+            try:
+                os.remove(path)
+            except EnvironmentError:
+                # ignore
+                pass
+
+    def __delete__(self, obj):
+        raise AttributeError("can't delete attribute")