text: """
  Objective-C runtime wrapper for use by LLDB Python formatters
  
  part of The LLVM Compiler Infrastructure
  This file is distributed under the University of Illinois Open Source
  License. See LICENSE.TXT for details.
  """
  import lldb
  import lldb.formatters.cache
  import lldb.formatters.attrib_fromdict
  import functools
  import lldb.formatters.Logger
  
  class Utilities:
  	@staticmethod
  	def read_ascii(process, pointer,max_len=128):
  		logger = lldb.formatters.Logger.Logger()
  		error = lldb.SBError()
  		content = None
  		try:
  			content = process.ReadCStringFromMemory(pointer,max_len,error)
  		except:
  			pass
  		if content is None or len(content) == 0 or error.fail:
  			return None
  		return content
  
  	@staticmethod
  	def is_valid_pointer(pointer, pointer_size, allow_tagged=0, allow_NULL=0):
  		logger = lldb.formatters.Logger.Logger()
  		if pointer is None:
  			return 0
  		if pointer == 0:
  			return allow_NULL
  		if allow_tagged and (pointer % 2) == 1:
  			return 1
  		return ((pointer % pointer_size) == 0)
  
  	# Objective-C runtime has a rule that pointers in a class_t will only have bits 0 thru 46 set
  	# so if any pointer has bits 47 thru 63 high we know that this is not a valid isa
  	@staticmethod
  	def is_allowed_pointer(pointer):
  		logger = lldb.formatters.Logger.Logger()
  		if pointer is None:
  			return 0
  		return ((pointer & 0xFFFF800000000000) == 0)
  
  	@staticmethod
  	def read_child_of(valobj,offset,type):
  		logger = lldb.formatters.Logger.Logger()
  		if offset == 0 and type.GetByteSize() == valobj.GetByteSize():
  			return valobj.GetValueAsUnsigned()
  		child = valobj.CreateChildAtOffset("childUNK",offset,type)
  		if child is None or child.IsValid() == 0:
  			return None;
  		return child.GetValueAsUnsigned()
  
  	@staticmethod
  	def is_valid_identifier(name):
  		logger = lldb.formatters.Logger.Logger()
  		if name is None:
  			return None
  		if len(name) == 0:
  			return None
  		# technically, the ObjC runtime does not enforce any rules about what name a class can have
  		# in practice, the commonly used byte values for a class name are the letters, digits and some
  		# symbols: $, %, -, _, .
  		# WARNING: this means that you cannot use this runtime implementation if you need to deal
  		# with class names that use anything but what is allowed here
  		ok_values = dict.fromkeys("$%_.-ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890")
  		return all(c in ok_values for c in name)
  
  	@staticmethod
  	def check_is_osx_lion(target):
  		logger = lldb.formatters.Logger.Logger()
  		# assume the only thing that has a Foundation.framework is a Mac
  		# assume anything < Lion does not even exist
  		mod = target.module['Foundation']
  		if mod is None or mod.IsValid() == 0:
  			return None
  		ver = mod.GetVersion()
  		if ver is None or ver == []:
  			return None
  		return (ver[0] < 900)
  
  	# a utility method that factors out code common to almost all the formatters
  	# takes in an SBValue and a metrics object
  	# returns a class_data and a wrapper (or None, if the runtime alone can't decide on a wrapper)
  	@staticmethod
  	def prepare_class_detection(valobj,statistics):
  		logger = lldb.formatters.Logger.Logger()
  		class_data = ObjCRuntime(valobj)
  		if class_data.is_valid() == 0:
  			statistics.metric_hit('invalid_pointer',valobj)
  			wrapper = InvalidPointer_Description(valobj.GetValueAsUnsigned(0) == 0)
  			return class_data,wrapper
  		class_data = class_data.read_class_data()
  		if class_data.is_valid() == 0:
  			statistics.metric_hit('invalid_isa',valobj)
  			wrapper = InvalidISA_Description()
  			return class_data,wrapper
  		if class_data.is_kvo():
  			class_data = class_data.get_superclass()
  		if class_data.is_valid() == 0:
  			statistics.metric_hit('invalid_isa',valobj)
  			wrapper = InvalidISA_Description()
  			return class_data,wrapper
  		return class_data,None
  
  
  class RoT_Data:
  	def __init__(self,rot_pointer,params):
  		logger = lldb.formatters.Logger.Logger()
  		if (Utilities.is_valid_pointer(rot_pointer.GetValueAsUnsigned(),params.pointer_size, allow_tagged=0)):
  			self.sys_params = params
  			self.valobj = rot_pointer
  			#self.flags = Utilities.read_child_of(self.valobj,0,self.sys_params.uint32_t)
  			#self.instanceStart = Utilities.read_child_of(self.valobj,4,self.sys_params.uint32_t)
  			self.instanceSize = None # lazy fetching
  			offset = 24 if self.sys_params.is_64_bit else 16
  			#self.ivarLayoutPtr = Utilities.read_child_of(self.valobj,offset,self.sys_params.addr_ptr_type)
  			self.namePointer = Utilities.read_child_of(self.valobj,offset,self.sys_params.types_cache.addr_ptr_type)
  			self.valid = 1 # self.check_valid()
  		else:
  			logger >> "Marking as invalid - rot is invalid"
  			self.valid = 0
  		if self.valid:
  			self.name = Utilities.read_ascii(self.valobj.GetTarget().GetProcess(),self.namePointer)
  			if not(Utilities.is_valid_identifier(self.name)):
  				logger >> "Marking as invalid - name is invalid"
  				self.valid = 0
  
  	# perform sanity checks on the contents of this class_ro_t
  	def check_valid(self):
  		self.valid = 1
  		# misaligned pointers seem to be possible for this field
  		#if not(Utilities.is_valid_pointer(self.namePointer,self.sys_params.pointer_size,allow_tagged=0)):
  		#	self.valid = 0
  		#	pass
  
  	def __str__(self):
  		logger = lldb.formatters.Logger.Logger()
  		return \
  		 "instanceSize = " + hex(self.instance_size()) + "\n" + \
  		 "namePointer = " + hex(self.namePointer) + " --> " + self.name
  
  	def is_valid(self):
  		return self.valid
  
  	def instance_size(self,align=0):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid() == 0:
  			return None
  		if self.instanceSize is None:
  			self.instanceSize = Utilities.read_child_of(self.valobj,8,self.sys_params.types_cache.uint32_t)
  		if align:
  			unalign = self.instance_size(0)
  			if self.sys_params.is_64_bit:
  				return ((unalign + 7) & ~7) % 0x100000000
  			else:
  				return ((unalign + 3) & ~3) % 0x100000000
  		else:
  			return self.instanceSize
  
  class RwT_Data:
  	def __init__(self,rwt_pointer,params):
  		logger = lldb.formatters.Logger.Logger()
  		if (Utilities.is_valid_pointer(rwt_pointer.GetValueAsUnsigned(),params.pointer_size, allow_tagged=0)):
  			self.sys_params = params
  			self.valobj = rwt_pointer
  			#self.flags = Utilities.read_child_of(self.valobj,0,self.sys_params.uint32_t)
  			#self.version = Utilities.read_child_of(self.valobj,4,self.sys_params.uint32_t)
  			self.roPointer = Utilities.read_child_of(self.valobj,8,self.sys_params.types_cache.addr_ptr_type)
  			self.check_valid()
  		else:
  			logger >> "Marking as invalid - rwt is invald"
  			self.valid = 0
  		if self.valid:
  			self.rot = self.valobj.CreateValueFromData("rot",lldb.SBData.CreateDataFromUInt64Array(self.sys_params.endianness, self.sys_params.pointer_size, [self.roPointer]),self.sys_params.types_cache.addr_ptr_type)
  #			self.rot = self.valobj.CreateValueFromAddress("rot",self.roPointer,self.sys_params.types_cache.addr_ptr_type).AddressOf()
  			self.data = RoT_Data(self.rot,self.sys_params)
  
  	# perform sanity checks on the contents of this class_rw_t
  	def check_valid(self):
  		logger = lldb.formatters.Logger.Logger()
  		self.valid = 1
  		if not(Utilities.is_valid_pointer(self.roPointer,self.sys_params.pointer_size,allow_tagged=0)):
  			logger >> "Marking as invalid - ropointer is invalid"
  			self.valid = 0
  
  	def __str__(self):
  		logger = lldb.formatters.Logger.Logger()
  		return \
  		 "roPointer = " + hex(self.roPointer)
  
  	def is_valid(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.valid:
  			return self.data.is_valid()
  		return 0
  
  class Class_Data_V2:
  	def __init__(self,isa_pointer,params):
  		logger = lldb.formatters.Logger.Logger()
  		if (isa_pointer != None) and (Utilities.is_valid_pointer(isa_pointer.GetValueAsUnsigned(),params.pointer_size, allow_tagged=0)):
  			self.sys_params = params
  			self.valobj = isa_pointer
  			self.check_valid()
  		else:
  			logger >> "Marking as invalid - isa is invalid or None"
  			self.valid = 0
  		if self.valid:
  			self.rwt = self.valobj.CreateValueFromData("rwt",lldb.SBData.CreateDataFromUInt64Array(self.sys_params.endianness, self.sys_params.pointer_size, [self.dataPointer]),self.sys_params.types_cache.addr_ptr_type)
  #			self.rwt = self.valobj.CreateValueFromAddress("rwt",self.dataPointer,self.sys_params.types_cache.addr_ptr_type).AddressOf()
  			self.data = RwT_Data(self.rwt,self.sys_params)
  
  	# perform sanity checks on the contents of this class_t
  	# this call tries to minimize the amount of data fetched- as soon as we have "proven"
  	# that we have an invalid object, we stop reading
  	def check_valid(self):
  		logger = lldb.formatters.Logger.Logger()
  		self.valid = 1
  
  		self.isaPointer = Utilities.read_child_of(self.valobj,0,self.sys_params.types_cache.addr_ptr_type)
  		if not(Utilities.is_valid_pointer(self.isaPointer,self.sys_params.pointer_size,allow_tagged=0)):
  			logger >> "Marking as invalid - isaPointer is invalid"
  			self.valid = 0
  			return
  		if not(Utilities.is_allowed_pointer(self.isaPointer)):
  			logger >> "Marking as invalid - isaPointer is not allowed"
  			self.valid = 0
  			return
  
  		self.cachePointer = Utilities.read_child_of(self.valobj,2*self.sys_params.pointer_size,self.sys_params.types_cache.addr_ptr_type)
  		if not(Utilities.is_valid_pointer(self.cachePointer,self.sys_params.pointer_size,allow_tagged=0)):
  			logger >> "Marking as invalid - cachePointer is invalid"
  			self.valid = 0
  			return
  		if not(Utilities.is_allowed_pointer(self.cachePointer)):
  			logger >> "Marking as invalid - cachePointer is not allowed"
  			self.valid = 0
  			return
  
  		self.vtablePointer = Utilities.read_child_of(self.valobj,3*self.sys_params.pointer_size,self.sys_params.types_cache.addr_ptr_type)
  		if not(Utilities.is_valid_pointer(self.vtablePointer,self.sys_params.pointer_size,allow_tagged=0)):
  			logger >> "Marking as invalid - vtablePointer is invalid"
  			self.valid = 0
  			return
  		if not(Utilities.is_allowed_pointer(self.vtablePointer)):
  			logger >> "Marking as invalid - vtablePointer is not allowed"
  			self.valid = 0
  			return
  
  		self.dataPointer = Utilities.read_child_of(self.valobj,4*self.sys_params.pointer_size,self.sys_params.types_cache.addr_ptr_type)
  		if not(Utilities.is_valid_pointer(self.dataPointer,self.sys_params.pointer_size,allow_tagged=0)):
  			logger >> "Marking as invalid - dataPointer is invalid"
  			self.valid = 0
  			return
  		if not(Utilities.is_allowed_pointer(self.dataPointer)):
  			logger >> "Marking as invalid - dataPointer is not allowed"
  			self.valid = 0
  			return
  
  		self.superclassIsaPointer = Utilities.read_child_of(self.valobj,1*self.sys_params.pointer_size,self.sys_params.types_cache.addr_ptr_type)
  		if not(Utilities.is_valid_pointer(self.superclassIsaPointer,self.sys_params.pointer_size,allow_tagged=0, allow_NULL=1)):
  			logger >> "Marking as invalid - superclassIsa is invalid"
  			self.valid = 0
  			return
  		if not(Utilities.is_allowed_pointer(self.superclassIsaPointer)):
  			logger >> "Marking as invalid - superclassIsa is not allowed"
  			self.valid = 0
  			return
  
  	# in general, KVO is implemented by transparently subclassing
  	# however, there could be exceptions where a class does something else
  	# internally to implement the feature - this method will have no clue that a class
  	# has been KVO'ed unless the standard implementation technique is used
  	def is_kvo(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid():
  			if self.class_name().startswith("NSKVONotifying_"):
  				return 1
  		return 0
  
  	# some CF classes have a valid ObjC isa in their CFRuntimeBase
  	# but instead of being class-specific this isa points to a match-'em-all class
  	# which is __NSCFType (the versions without __ also exists and we are matching to it
  	#                      just to be on the safe side)
  	def is_cftype(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid():
  			return self.class_name() == '__NSCFType' or self.class_name() == 'NSCFType'
  
  	def get_superclass(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid():
  			parent_isa_pointer = self.valobj.CreateChildAtOffset("parent_isa",
  				self.sys_params.pointer_size,
  				self.sys_params.addr_ptr_type)
  			return Class_Data_V2(parent_isa_pointer,self.sys_params)
  		else:
  			return None
  
  	def class_name(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid():
  			return self.data.data.name
  		else:
  			return None
  
  	def is_valid(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.valid:
  			return self.data.is_valid()
  		return 0
  
  	def __str__(self):
  		logger = lldb.formatters.Logger.Logger()
  		return 'isaPointer = ' + hex(self.isaPointer) + "\n" + \
  		 "superclassIsaPointer = " + hex(self.superclassIsaPointer) + "\n" + \
  		 "cachePointer = " + hex(self.cachePointer) + "\n" + \
  		 "vtablePointer = " + hex(self.vtablePointer) + "\n" + \
  		 "data = " + hex(self.dataPointer)
  
  	def is_tagged(self):
  		return 0
  
  	def instance_size(self,align=0):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid() == 0:
  			return None
  		return self.rwt.rot.instance_size(align)
  
  # runtime v1 is much less intricate than v2 and stores relevant information directly in the class_t object
  class Class_Data_V1:
  	def __init__(self,isa_pointer,params):
  		logger = lldb.formatters.Logger.Logger()
  		if (isa_pointer != None) and (Utilities.is_valid_pointer(isa_pointer.GetValueAsUnsigned(),params.pointer_size, allow_tagged=0)):
  			self.valid = 1
  			self.sys_params = params
  			self.valobj = isa_pointer
  			self.check_valid()
  		else:
  			logger >> "Marking as invalid - isaPointer is invalid or None"
  			self.valid = 0
  		if self.valid:
  			self.name = Utilities.read_ascii(self.valobj.GetTarget().GetProcess(),self.namePointer)
  			if not(Utilities.is_valid_identifier(self.name)):
  				logger >> "Marking as invalid - name is not valid"
  				self.valid = 0
  
  	# perform sanity checks on the contents of this class_t
  	def check_valid(self):
  		logger = lldb.formatters.Logger.Logger()
  		self.valid = 1
  
  		self.isaPointer = Utilities.read_child_of(self.valobj,0,self.sys_params.types_cache.addr_ptr_type)
  		if not(Utilities.is_valid_pointer(self.isaPointer,self.sys_params.pointer_size,allow_tagged=0)):
  			logger >> "Marking as invalid - isaPointer is invalid"
  			self.valid = 0
  			return
  
  		self.superclassIsaPointer = Utilities.read_child_of(self.valobj,1*self.sys_params.pointer_size,self.sys_params.types_cache.addr_ptr_type)
  		if not(Utilities.is_valid_pointer(self.superclassIsaPointer,self.sys_params.pointer_size,allow_tagged=0,allow_NULL=1)):
  			logger >> "Marking as invalid - superclassIsa is invalid"
  			self.valid = 0
  			return
  
  		self.namePointer = Utilities.read_child_of(self.valobj,2*self.sys_params.pointer_size,self.sys_params.types_cache.addr_ptr_type)
  		#if not(Utilities.is_valid_pointer(self.namePointer,self.sys_params.pointer_size,allow_tagged=0,allow_NULL=0)):
  		#	self.valid = 0
  		#	return
  
  	# in general, KVO is implemented by transparently subclassing
  	# however, there could be exceptions where a class does something else
  	# internally to implement the feature - this method will have no clue that a class
  	# has been KVO'ed unless the standard implementation technique is used
  	def is_kvo(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid():
  			if self.class_name().startswith("NSKVONotifying_"):
  				return 1
  		return 0
  
  	# some CF classes have a valid ObjC isa in their CFRuntimeBase
  	# but instead of being class-specific this isa points to a match-'em-all class
  	# which is __NSCFType (the versions without __ also exists and we are matching to it
  	#                      just to be on the safe side)
  	def is_cftype(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid():
  			return self.class_name() == '__NSCFType' or self.class_name() == 'NSCFType'
  
  	def get_superclass(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid():
  			parent_isa_pointer = self.valobj.CreateChildAtOffset("parent_isa",
  				self.sys_params.pointer_size,
  				self.sys_params.addr_ptr_type)
  			return Class_Data_V1(parent_isa_pointer,self.sys_params)
  		else:
  			return None
  
  	def class_name(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid():
  			return self.name
  		else:
  			return None
  
  	def is_valid(self):
  		return self.valid
  
  	def __str__(self):
  		logger = lldb.formatters.Logger.Logger()
  		return 'isaPointer = ' + hex(self.isaPointer) + "\n" + \
  		 "superclassIsaPointer = " + hex(self.superclassIsaPointer) + "\n" + \
  		 "namePointer = " + hex(self.namePointer) + " --> " + self.name + \
  		 "instanceSize = " + hex(self.instanceSize()) + "\n"
  
  	def is_tagged(self):
  		return 0
  
  	def instance_size(self,align=0):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid() == 0:
  			return None
  		if self.instanceSize is None:
  			self.instanceSize = Utilities.read_child_of(self.valobj,5*self.sys_params.pointer_size,self.sys_params.types_cache.addr_ptr_type)
  		if align:
  			unalign = self.instance_size(0)
  			if self.sys_params.is_64_bit:
  				return ((unalign + 7) & ~7) % 0x100000000
  			else:
  				return ((unalign + 3) & ~3) % 0x100000000
  		else:
  			return self.instanceSize
  
  # these are the only tagged pointers values for current versions
  # of OSX - they might change in future OS releases, and no-one is
  # advised to rely on these values, or any of the bitmasking formulas
  # in TaggedClass_Data. doing otherwise is at your own risk
  TaggedClass_Values_Lion = {1 : 'NSNumber', \
                             5: 'NSManagedObject', \
                             6: 'NSDate', \
                             7: 'NSDateTS' };
  TaggedClass_Values_NMOS = {0: 'NSAtom', \
                             3 : 'NSNumber', \
                             4: 'NSDateTS', \
                             5: 'NSManagedObject', \
                             6: 'NSDate' };
  
  class TaggedClass_Data:
  	def __init__(self,pointer,params):
  		logger = lldb.formatters.Logger.Logger()
  		global TaggedClass_Values_Lion,TaggedClass_Values_NMOS
  		self.valid = 1
  		self.name = None
  		self.sys_params = params
  		self.valobj = pointer
  		self.val = (pointer & ~0x0000000000000000FF) >> 8
  		self.class_bits = (pointer & 0xE) >> 1
  		self.i_bits = (pointer & 0xF0) >> 4
  
  		if self.sys_params.is_lion:
  			if self.class_bits in TaggedClass_Values_Lion:
  				self.name = TaggedClass_Values_Lion[self.class_bits]
  			else:
  				logger >> "Marking as invalid - not a good tagged pointer for Lion"
  				self.valid = 0
  		else:
  			if self.class_bits in TaggedClass_Values_NMOS:
  				self.name = TaggedClass_Values_NMOS[self.class_bits]
  			else:
  				logger >> "Marking as invalid - not a good tagged pointer for NMOS"
  				self.valid = 0
  
  
  	def is_valid(self):
  		return self.valid
  
  	def class_name(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid():
  			return self.name
  		else:
  			return 0
  
  	def value(self):
  		return self.val if self.is_valid() else None
  
  	def info_bits(self):
  		return self.i_bits if self.is_valid() else None
  
  	def is_kvo(self):
  		return 0
  
  	def is_cftype(self):
  		return 0
  
  	# we would need to go around looking for the superclass or ask the runtime
  	# for now, we seem not to require support for this operation so we will merrily
  	# pretend to be at a root point in the hierarchy
  	def get_superclass(self):
  		return None
  
  	# anything that is handled here is tagged
  	def is_tagged(self):
  		return 1
  
  	# it seems reasonable to say that a tagged pointer is the size of a pointer
  	def instance_size(self,align=0):
  		logger = lldb.formatters.Logger.Logger()
  		if self.is_valid() == 0:
  			return None
  		return self.sys_params.pointer_size
  
  
  class InvalidClass_Data:
  	def __init__(self):
  		pass
  	def is_valid(self):
  		return 0
  
  
  class Version:
  	def __init__(self, major, minor, release, build_string):
  		self._major = major
  		self._minor = minor
  		self._release = release
  		self._build_string = build_string
  
  	def get_major(self):
  		return self._major
  	def get_minor(self):
  		return self._minor
  	def get_release(self):
  		return self._release
  	def get_build_string(self):
  		return self._build_string
  
  	major = property(get_major,None)
  	minor = property(get_minor,None)
  	release = property(get_release,None)
  	build_string = property(get_build_string,None)
  
  	def __lt__(self,other):
  		if (self.major < other.major):
  			return 1
  		if (self.minor < other.minor):
  			return 1
  		if (self.release < other.release):
  			return 1
  		# build strings are not compared since they are heavily platform-dependent and might not always
  		# be available
  		return 0
  
  	def __eq__(self,other):
  		return (self.major == other.major) and \
  		       (self.minor == other.minor) and \
  		       (self.release == other.release) and \
  		       (self.build_string == other.build_string)
  
  	# Python 2.6 doesn't have functools.total_ordering, so we have to implement
  	# other comparators
  	def __gt__(self, other):
  		return other < self
  
  	def __le__(self, other):
  		return not other < self
  
  	def __ge__(self, other):
  		return not self < other
  
  
  runtime_version = lldb.formatters.cache.Cache()
  os_version = lldb.formatters.cache.Cache()
  types_caches = lldb.formatters.cache.Cache()
  isa_caches = lldb.formatters.cache.Cache()
  
  class SystemParameters:
  	def __init__(self,valobj):
  		logger = lldb.formatters.Logger.Logger()
  		self.adjust_for_architecture(valobj)
  		self.adjust_for_process(valobj)
  
  	def adjust_for_process(self, valobj):
  		logger = lldb.formatters.Logger.Logger()
  		global runtime_version
  		global os_version
  		global types_caches
  		global isa_caches
  
  		process = valobj.GetTarget().GetProcess()
  		self.pid = process.GetProcessID()
  
  		if runtime_version.look_for_key(self.pid):
  			self.runtime_version = runtime_version.get_value(self.pid)
  		else:
  			self.runtime_version = ObjCRuntime.runtime_version(process)
  			runtime_version.add_item(self.pid,self.runtime_version)
  
  		if os_version.look_for_key(self.pid):
  			self.is_lion = os_version.get_value(self.pid)
  		else:
  			self.is_lion = Utilities.check_is_osx_lion(valobj.GetTarget())
  			os_version.add_item(self.pid,self.is_lion)
  
  		if types_caches.look_for_key(self.pid):
  			self.types_cache = types_caches.get_value(self.pid)
  		else:
  			self.types_cache = lldb.formatters.attrib_fromdict.AttributesDictionary(allow_reset=0)
  			self.types_cache.addr_type = valobj.GetType().GetBasicType(lldb.eBasicTypeUnsignedLong)
  			self.types_cache.addr_ptr_type = self.types_cache.addr_type.GetPointerType()
  			self.types_cache.uint32_t = valobj.GetType().GetBasicType(lldb.eBasicTypeUnsignedInt)
  			types_caches.add_item(self.pid,self.types_cache)
  
  		if isa_caches.look_for_key(self.pid):
  			self.isa_cache = isa_caches.get_value(self.pid)
  		else:
  			self.isa_cache = lldb.formatters.cache.Cache()
  			isa_caches.add_item(self.pid,self.isa_cache)
  
  	def adjust_for_architecture(self,valobj):
  		process = valobj.GetTarget().GetProcess()
  		self.pointer_size = process.GetAddressByteSize()
  		self.is_64_bit = (self.pointer_size == 8)
  		self.endianness = process.GetByteOrder()
  		self.is_little = (self.endianness == lldb.eByteOrderLittle)
  		self.cfruntime_size = 16 if self.is_64_bit else 8
  
  	# a simple helper function that makes it more explicit that one is calculating
  	# an offset that is made up of X pointers and Y bytes of additional data
  	# taking into account pointer size - if you know there is going to be some padding
  	# you can pass that in and it will be taken into account (since padding may be different between
  	# 32 and 64 bit versions, you can pass padding value for both, the right one will be used)
  	def calculate_offset(self, num_pointers = 0, bytes_count = 0, padding32 = 0, padding64 = 0):
  		value = bytes_count + num_pointers*self.pointer_size
  		return value + padding64 if self.is_64_bit else value + padding32
  
  class ObjCRuntime:
  
  	# the ObjC runtime has no explicit "version" field that we can use
  	# instead, we discriminate v1 from v2 by looking for the presence
  	# of a well-known section only present in v1
  	@staticmethod
  	def runtime_version(process):
  		logger = lldb.formatters.Logger.Logger()
  		if process.IsValid() == 0:
  			logger >> "No process - bailing out"
  			return None
  		target = process.GetTarget()
  		num_modules = target.GetNumModules()
  		module_objc = None
  		for idx in range(num_modules):
  			module = target.GetModuleAtIndex(idx)
  			if module.GetFileSpec().GetFilename() == 'libobjc.A.dylib':
  				module_objc = module
  				break
  		if module_objc is None or module_objc.IsValid() == 0:
  			logger >> "no libobjc - bailing out"
  			return None
  		num_sections = module.GetNumSections()
  		section_objc = None
  		for idx in range(num_sections):
  			section = module.GetSectionAtIndex(idx)
  			if section.GetName() == '__OBJC':
  				section_objc = section
  				break
  		if section_objc != None and section_objc.IsValid():
  			logger >> "found __OBJC: v1"
  			return 1
  		logger >> "no __OBJC: v2"
  		return 2
  
  	@staticmethod
  	def runtime_from_isa(isa):
  		logger = lldb.formatters.Logger.Logger()
  		runtime = ObjCRuntime(isa)
  		runtime.isa = isa
  		return runtime
  
  	def __init__(self,valobj):
  		logger = lldb.formatters.Logger.Logger()
  		self.valobj = valobj
  		self.adjust_for_architecture()
  		self.sys_params = SystemParameters(self.valobj)
  		self.unsigned_value = self.valobj.GetValueAsUnsigned()
  		self.isa_value = None
  
  	def adjust_for_architecture(self):
  		pass
  
  # an ObjC pointer can either be tagged or must be aligned
  	def is_tagged(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.valobj is None:
  			return 0
  		return (Utilities.is_valid_pointer(self.unsigned_value,self.sys_params.pointer_size, allow_tagged=1) and \
  		not(Utilities.is_valid_pointer(self.unsigned_value,self.sys_params.pointer_size, allow_tagged=0)))
  
  	def is_valid(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.valobj is None:
  			return 0
  		if self.valobj.IsInScope() == 0:
  			return 0
  		return Utilities.is_valid_pointer(self.unsigned_value,self.sys_params.pointer_size, allow_tagged=1)
  
  	def is_nil(self):
  		return self.unsigned_value == 0
  
  	def read_isa(self):
  		logger = lldb.formatters.Logger.Logger()
  		if self.isa_value != None:
  			logger >> "using cached isa"
  			return self.isa_value
  		self.isa_pointer = self.valobj.CreateChildAtOffset("cfisa",
  			0,
  			self.sys_params.types_cache.addr_ptr_type)
  		if self.isa_pointer is None or self.isa_pointer.IsValid() == 0:
  			logger >> "invalid isa - bailing out"
  			return None;
  		self.isa_value = self.isa_pointer.GetValueAsUnsigned(1)
  		if self.isa_value == 1:
  			logger >> "invalid isa value - bailing out"
  			return None;
  		return Ellipsis
  
  	def read_class_data(self):
  		logger = lldb.formatters.Logger.Logger()
  		global isa_cache
  		if self.is_tagged():
  			# tagged pointers only exist in ObjC v2
  			if self.sys_params.runtime_version == 2:
  				logger >> "on v2 and tagged - maybe"
  				# not every odd-valued pointer is actually tagged. most are just plain wrong
  				# we could try and predetect this before even creating a TaggedClass_Data object
  				# but unless performance requires it, this seems a cleaner way to tackle the task
  				tentative_tagged = TaggedClass_Data(self.unsigned_value,self.sys_params)
  				if tentative_tagged.is_valid():
  					logger >> "truly tagged"
  					return tentative_tagged
  				else:
  					logger >> "not tagged - error"
  					return InvalidClass_Data()
  			else:
  				logger >> "on v1 and tagged - error"
  				return InvalidClass_Data()
  		if self.is_valid() == 0 or self.read_isa() is None:
  			return InvalidClass_Data()
  		data = self.sys_params.isa_cache.get_value(self.isa_value,default=None)
  		if data != None:
  			return data
  		if self.sys_params.runtime_version == 2:
  			data = Class_Data_V2(self.isa_pointer,self.sys_params)
  		else:
  			data = Class_Data_V1(self.isa_pointer,self.sys_params)
  		if data is None:
  			return InvalidClass_Data()
  		if data.is_valid():
  			self.sys_params.isa_cache.add_item(self.isa_value,data,ok_to_replace=1)
  		return data
  
  # these classes below can be used by the data formatters to provide a consistent message that describes a given runtime-generated situation
  class SpecialSituation_Description:
  	def message(self):
  		return ''
  
  class InvalidPointer_Description(SpecialSituation_Description):
  
  	def __init__(self,nil):
  		self.is_nil = nil
  
  	def message(self):
  		if self.is_nil:
  			return '@"<nil>"'
  		else:
  			return '<invalid pointer>'
  
  class InvalidISA_Description(SpecialSituation_Description):
  
  	def __init__(self):
  		pass
  
  	def message(self):
  		return '<not an Objective-C object>'
  
  