Copy cfg and iniparser from oslo-incubator

https://review.openstack.org/20753 introduced tools/install_venv_common.py
but not it's dependencies openstack.common.{cfg,iniparser}

Change-Id: I270a1d8f6fd8f93988a5e2ccbc446adda0a6cd81

openstack-common.conf

@@ -1,7 +1,7 @@
 [DEFAULT]
 
 # The list of modules to copy from openstack-common
-modules=install_venv_common,openstackkeyring,setup
+modules=cfg,iniparser,install_venv_common,openstackkeyring,setup
 
 # The base module to hold the copy of openstack.common
 base=openstackclient

openstackclient/openstack/common/iniparser.py

@@ -0,0 +1,130 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2012 OpenStack LLC.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+
+class ParseError(Exception):
+    def __init__(self, message, lineno, line):
+        self.msg = message
+        self.line = line
+        self.lineno = lineno
+
+    def __str__(self):
+        return 'at line %d, %s: %r' % (self.lineno, self.msg, self.line)
+
+
+class BaseParser(object):
+    lineno = 0
+    parse_exc = ParseError
+
+    def _assignment(self, key, value):
+        self.assignment(key, value)
+        return None, []
+
+    def _get_section(self, line):
+        if line[-1] != ']':
+            return self.error_no_section_end_bracket(line)
+        if len(line) <= 2:
+            return self.error_no_section_name(line)
+
+        return line[1:-1]
+
+    def _split_key_value(self, line):
+        colon = line.find(':')
+        equal = line.find('=')
+        if colon < 0 and equal < 0:
+            return self.error_invalid_assignment(line)
+
+        if colon < 0 or (equal >= 0 and equal < colon):
+            key, value = line[:equal], line[equal + 1:]
+        else:
+            key, value = line[:colon], line[colon + 1:]
+
+        value = value.strip()
+        if ((value and value[0] == value[-1]) and
+                (value[0] == "\"" or value[0] == "'")):
+            value = value[1:-1]
+        return key.strip(), [value]
+
+    def parse(self, lineiter):
+        key = None
+        value = []
+
+        for line in lineiter:
+            self.lineno += 1
+
+            line = line.rstrip()
+            if not line:
+                # Blank line, ends multi-line values
+                if key:
+                    key, value = self._assignment(key, value)
+                continue
+            elif line[0] in (' ', '\t'):
+                # Continuation of previous assignment
+                if key is None:
+                    self.error_unexpected_continuation(line)
+                else:
+                    value.append(line.lstrip())
+                continue
+
+            if key:
+                # Flush previous assignment, if any
+                key, value = self._assignment(key, value)
+
+            if line[0] == '[':
+                # Section start
+                section = self._get_section(line)
+                if section:
+                    self.new_section(section)
+            elif line[0] in '#;':
+                self.comment(line[1:].lstrip())
+            else:
+                key, value = self._split_key_value(line)
+                if not key:
+                    return self.error_empty_key(line)
+
+        if key:
+            # Flush previous assignment, if any
+            self._assignment(key, value)
+
+    def assignment(self, key, value):
+        """Called when a full assignment is parsed"""
+        raise NotImplementedError()
+
+    def new_section(self, section):
+        """Called when a new section is started"""
+        raise NotImplementedError()
+
+    def comment(self, comment):
+        """Called when a comment is parsed"""
+        pass
+
+    def error_invalid_assignment(self, line):
+        raise self.parse_exc("No ':' or '=' found in assignment",
+                             self.lineno, line)
+
+    def error_empty_key(self, line):
+        raise self.parse_exc('Key cannot be empty', self.lineno, line)
+
+    def error_unexpected_continuation(self, line):
+        raise self.parse_exc('Unexpected continuation line',
+                             self.lineno, line)
+
+    def error_no_section_end_bracket(self, line):
+        raise self.parse_exc('Invalid section (must end with ])',
+                             self.lineno, line)
+
+    def error_no_section_name(self, line):
+        raise self.parse_exc('Empty section name', self.lineno, line)