Merge branch 'config' into improvements

* config:
  added additional testing for the configuration, concurrent access and config reading, all tests work
  implemented config class as far as necessary, one check is still failing
  Added frame for configuration reader involving a meta class, decorators and tests - most of which still has to be filled out

1 files changed, 328 insertions, 0 deletions

diff --git a/lib/git/config.py b/lib/git/config.py
new file mode 100644
index 00000000..b555677e
--- /dev/null
+++ b/lib/git/config.py
@@ -0,0 +1,328 @@
+# 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
+import os
+import ConfigParser as cp
+from git.odict import OrderedDict
+import inspect
+
+class _MetaParserBuilder(type):
+	"""
+	Utlity class wrapping base-class methods into decorators that assure read-only properties
+	"""
+	def __new__(metacls, name, bases, clsdict):
+		"""
+		Equip all base-class methods with a _needs_values decorator, and all non-const methods
+		with a _set_dirty_and_flush_changes decorator in addition to that.
+		"""
+		mutating_methods = clsdict['_mutating_methods_']
+		for base in bases:
+			methods = ( t for t in inspect.getmembers(base, inspect.ismethod) if not t[0].startswith("_") )
+			for name, method in methods:
+				if name in clsdict:
+					continue
+				method_with_values = _needs_values(method)
+				if name in mutating_methods:
+					method_with_values = _set_dirty_and_flush_changes(method_with_values)
+				# END mutating methods handling
+				
+				clsdict[name] = method_with_values
+		# END for each base
+		
+		new_type = super(_MetaParserBuilder, metacls).__new__(metacls, name, bases, clsdict)
+		return new_type
+	
+	
+
+def _needs_values(func):
+	"""
+	Returns method assuring we read values (on demand) before we try to access them
+	"""
+	def assure_data_present(self, *args, **kwargs):
+		self.read()
+		return func(self, *args, **kwargs)
+	# END wrapper method
+	assure_data_present.__name__ = func.__name__
+	return assure_data_present
+	
+def _set_dirty_and_flush_changes(non_const_func):
+	"""
+	Return method that checks whether given non constant function may be called.
+	If so, the instance will be set dirty.
+	Additionally, we flush the changes right to disk
+	"""
+	def flush_changes(self, *args, **kwargs):
+		rval = non_const_func(self, *args, **kwargs)
+		self.write()
+		return rval
+	# END wrapper method
+	flush_changes.__name__ = non_const_func.__name__
+	return flush_changes
+	
+	
+
+class GitConfigParser(cp.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.
+	
+	NOTE
+		The config is case-sensitive even when queried, hence section and option names
+		must match perfectly.
+	"""
+	__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_ = ("add_section", "remove_section", "remove_option", "set")
+	
+	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
+		
+		``file_or_files``
+			A single file path or file objects or multiple of these
+		
+		``read_only``
+			If True, the ConfigParser may only read the data , but not change it.
+			If False, only a single file path or file object may be given.
+		"""
+		# initialize base with ordered dictionaries to be sure we write the same 
+		# file back 
+		self._sections = OrderedDict()
+		self._defaults = OrderedDict()
+		
+		self._file_or_files = file_or_files
+		self._read_only = read_only
+		self._owns_lock = False
+		self._is_initialized = False
+		
+		
+		if not read_only:
+			if isinstance(file_or_files, (tuple, list)):
+				raise ValueError("Write-ConfigParsers can operate on a single file only, multiple files have been passed")
+			# END single file check
+			
+			self._file_name = file_or_files
+			if not isinstance(self._file_name, basestring):
+				self._file_name = file_or_files.name
+			# END get filename
+			
+			self._obtain_lock_or_raise()	
+		# END read-only check
+		
+	
+	def __del__(self):
+		"""
+		Write pending changes if required and release locks
+		"""
+		# checking for the lock here makes sure we do not raise during write()
+		# in case an invalid parser was created who could not get a lock
+		if self.read_only or not self._has_lock():
+			return
+		
+		try:
+			try:
+				self.write()
+			except IOError,e:
+				print "Exception during destruction of GitConfigParser: %s" % str(e)
+		finally:
+			self._release_lock()
+	
+	def _lock_file_path(self):
+		"""
+		Return
+			Path to lockfile
+		"""
+		return "%s.lock" % (self._file_name)
+	
+	def _has_lock(self):
+		"""
+		Return
+			True if we have a lock and if the lockfile still exists
+			
+		Raise
+			AssertionError if our lock-file does not exist
+		"""
+		if not self._owns_lock:
+			return False
+		
+		lock_file = self._lock_file_path()
+		try:
+			fp = open(lock_file, "r")
+			pid = int(fp.read())
+			fp.close()
+		except IOError:
+			raise AssertionError("GitConfigParser has a lock but the lock file at %s could not be read" % lock_file)
+		
+		if pid != os.getpid():
+			raise AssertionError("We claim to own the lock at %s, but it was not owned by our process: %i" % (lock_file, os.getpid()))
+		
+		return True
+		
+	def _obtain_lock_or_raise(self):
+		"""
+		Create a lock file as flag for other instances, mark our instance as lock-holder
+		
+		Raise
+			IOError if a lock was already present or a lock file could not be written
+		"""
+		if self._has_lock():
+			return 
+			
+		lock_file = self._lock_file_path()
+		if os.path.exists(lock_file):
+			raise IOError("Lock for file %r did already exist, delete %r in case the lock is illegal" % (self._file_name, lock_file))
+		
+		fp = open(lock_file, "w")
+		fp.write(str(os.getpid()))
+		fp.close()
+		
+		self._owns_lock = True
+		
+	def _release_lock(self):
+		"""
+		Release our lock if we have one
+		"""
+		if not self._has_lock():
+			return 
+			
+		os.remove(self._lock_file_path())
+		self._owns_lock = False
+		
+	def optionxform(self, optionstr):
+		"""
+		Do not transform options in any way when writing
+		"""
+		return optionstr
+	
+	def read(self):
+		"""
+		Reads the data stored in the files we have been initialized with
+		
+		Returns
+			Nothing
+		
+		Raises
+			IOError if not all files could be read
+		"""
+		if self._is_initialized:
+			return
+			
+		
+		files_to_read = self._file_or_files
+		if not isinstance(files_to_read, (tuple, list)):
+			files_to_read = [ files_to_read ]
+		
+		for file_object in files_to_read:
+			fp = file_object
+			close_fp = False
+			# assume a path if it is not a file-object
+			if not hasattr(file_object, "seek"):
+				fp = open(file_object)
+				close_fp = True
+			# END fp handling
+				
+			try:
+				self._read(fp, fp.name)
+			finally:
+				if close_fp:
+					fp.close()
+			# END read-handling
+		# END  for each file object to read
+		self._is_initialized = True
+		
+	def _write(self, fp):
+		"""Write an .ini-format representation of the configuration state in 
+		git compatible format"""
+		def write_section(name, section_dict):
+			fp.write("[%s]\n" % name)
+			for (key, value) in section_dict.items():
+				if key != "__name__":
+					fp.write("\t%s = %s\n" % (key, str(value).replace('\n', '\n\t')))
+				# END if key is not __name__
+		# END section writing 
+		
+		if self._defaults:
+			write_section(cp.DEFAULTSECT, self._defaults)
+		map(lambda t: write_section(t[0],t[1]), self._sections.items())
+
+		
+	@_needs_values
+	def write(self):
+		"""
+		Write changes to our file, if there are changes at all
+		
+		Raise
+			IOError if this is a read-only writer instance or if we could not obtain 
+			a file lock
+		"""
+		self._assure_writable("write")
+		self._obtain_lock_or_raise()
+		
+		
+		fp = self._file_or_files
+		close_fp = False
+		
+		if not hasattr(fp, "seek"):
+			fp = open(self._file_or_files, "w")
+			close_fp = True
+		else:
+			fp.seek(0)
+		
+		# WRITE DATA
+		try:
+			self._write(fp)
+		finally:
+			if close_fp:
+				fp.close()
+		# END data writing
+			
+		# we do not release the lock - it will be done automatically once the 
+		# instance vanishes
+		
+	def _assure_writable(self, method_name):
+		if self.read_only:
+			raise IOError("Cannot execute non-constant method %s.%s" % (self, method_name))
+		
+	@_needs_values
+	@_set_dirty_and_flush_changes
+	def add_section(self, section):
+		"""
+		Assures added options will stay in order
+		"""
+		super(GitConfigParser, self).add_section(section)
+		self._sections[section] = OrderedDict()
+		
+	@property
+	def read_only(self):
+		"""
+		Returns
+			True if this instance may change the configuration file
+		"""
+		return self._read_only