1 files changed, 236 insertions, 20 deletions

diff --git a/lib/git/config.py b/lib/git/config.py
index c7f2c398..0187af1d 100644
--- a/lib/git/config.py
+++ b/lib/git/config.py
@@ -9,24 +9,67 @@ configuration files
 """
 
 import re
-from ConfigParser import RawConfigParser
+import os
+import ConfigParser as cp
+from git.odict import OrderedDict
+import inspect
 
 class _MetaParserBuilder(type):
 	"""
-	Utlity class wrapping methods into decorators that assure read-only properties
+	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.
+		"""
+		new_type = super(_MetaParserBuilder, metacls).__new__(metacls, name, bases, clsdict)
+		
+		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
+		
+		return new_type
+	
+	
 
 def _needs_values(func):
-	"""Returns method assuring we read values (on demand) before we try to access them"""
-	return 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 _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"""
+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(RawConfigParser, object):
+class GitConfigParser(cp.RawConfigParser, object):
 	"""
 	Implements specifics required to read git style configuration files.
 	
@@ -38,6 +81,10 @@ class GitConfigParser(RawConfigParser, object):
 	
 	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
 	
@@ -51,45 +98,214 @@ class GitConfigParser(RawConfigParser, object):
 		)
 	
 	# list of RawConfigParser methods able to change the instance
-	_mutating_methods_ = tuple()	
-	
+	_mutating_methods_ = ("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 
+		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
-		self._is_dirty = 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
 		"""
+		if self.read_only:
+			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):
 		"""
-		Read configuration information from our file or files
+		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 
+			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, "w")
+				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
 		
-	@_ensure_writable
+	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())
+
+		
 	def write(self):
 		"""
-		Write our changes to our file
+		Write changes to our file, if there are changes at all
 		
 		Raise
-			AssertionError if this is a read-only writer instance
+			IOError if this is a read-only writer instance or if we could not obtain 
+			a file lock
 		"""
-		if not self._is_dirty:
-			return
+		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
 		
-		self._is_dirty = False
+	def _assure_writable(self, method_name):
+		if self.read_only:
+			raise IOError("Cannot execute non-constant method %s.%s" % (self, method_name))
 		
 	@property
 	def read_only(self):