Added frame for configuration reader involving a meta class, decorators and tests - most of which still has to be filled out

1 files changed, 100 insertions, 0 deletions

diff --git a/lib/git/config.py b/lib/git/config.py
new file mode 100644
index 00000000..c7f2c398
--- /dev/null
+++ b/lib/git/config.py
@@ -0,0 +1,100 @@
+# config.py
+# Copyright (C) 2008, 2009 Michael Trier (mtrier@gmail.com) and contributors
+#
+# This module is part of GitPython and is released under
+# the BSD License: http://www.opensource.org/licenses/bsd-license.php
+"""
+Module containing module parser implementation able to properly read and write
+configuration files
+"""
+
+import re
+from ConfigParser import RawConfigParser
+
+class _MetaParserBuilder(type):
+	"""
+	Utlity class wrapping methods into decorators that assure read-only properties
+	"""
+
+def _needs_values(func):
+	"""Returns method assuring we read values (on demand) before we try to access them"""
+	return func
+	
+def _ensure_writable(non_const_func):
+	"""Return method that checks whether given non constant function may be called.
+	If so, the instance will be set dirty"""
+	
+	
+
+class GitConfigParser(RawConfigParser, object):
+	"""
+	Implements specifics required to read git style configuration files.
+	
+	This variation behaves much like the git.config command such that the configuration
+	will be read on demand based on the filepath given during initialization.
+	
+	The changes will automatically be written once the instance goes out of scope, but 
+	can be triggered manually as well.
+	
+	The configuration file will be locked if you intend to change values preventing other 
+	instances to write concurrently.
+	"""
+	__metaclass__ = _MetaParserBuilder
+	
+	OPTCRE = re.compile(
+		r'\s?(?P<option>[^:=\s][^:=]*)'		  # very permissive, incuding leading whitespace
+		r'\s*(?P<vi>[:=])\s*'				  # any number of space/tab,
+											  # followed by separator
+											  # (either : or =), followed
+											  # by any # space/tab
+		r'(?P<value>.*)$'					  # everything up to eol
+		)
+	
+	# list of RawConfigParser methods able to change the instance
+	_mutating_methods_ = tuple()	
+	
+	
+	def __init__(self, file_or_files, read_only=True):
+		"""
+		Initialize a configuration reader to read the given file_or_files and to 
+		possibly allow changes to it by setting read_only False 
+		"""
+		self._file_or_files = file_or_files
+		self._read_only = read_only
+		self._is_initialized = False
+		self._is_dirty = False
+	
+	def __del__(self):
+		"""
+		Write pending changes if required and release locks
+		"""
+	
+	def read(self):
+		"""
+		Read configuration information from our file or files
+		"""
+		if self._is_initialized:
+			return 
+		
+		self._is_initialized = True
+		
+	@_ensure_writable
+	def write(self):
+		"""
+		Write our changes to our file
+		
+		Raise
+			AssertionError if this is a read-only writer instance
+		"""
+		if not self._is_dirty:
+			return
+		
+		self._is_dirty = False
+		
+	@property
+	def read_only(self):
+		"""
+		Returns
+			True if this instance may change the configuration file
+		"""
+		return self._read_only