CFBag.py

"""
LLDB AppKit formatters

part of The LLVM Compiler Infrastructure
This file is distributed under the University of Illinois Open Source
License. See LICENSE.TXT for details.
"""
# summary provider for CFBag
import lldb
import ctypes
import objc_runtime
import metrics
import Logger

statistics = metrics.Metrics()
statistics.add_metric('invalid_isa')
statistics.add_metric('invalid_pointer')
statistics.add_metric('unknown_class')
statistics.add_metric('code_notrun')

# despite the similary to synthetic children providers, these classes are not
# trying to provide anything but the length for an CFBag, so they need not
# obey the interface specification for synthetic children providers
class CFBagRef_SummaryProvider:
	def adjust_for_architecture(self):
		pass

	def __init__(self, valobj, params):
		logger = Logger.Logger()
		self.valobj = valobj;
		self.sys_params = params
		if not(self.sys_params.types_cache.NSUInteger):
			if self.sys_params.is_64_bit:
				self.sys_params.types_cache.NSUInteger = self.valobj.GetType().GetBasicType(lldb.eBasicTypeUnsignedLong)
			else:
				self.sys_params.types_cache.NSUInteger = self.valobj.GetType().GetBasicType(lldb.eBasicTypeUnsignedInt)
		self.update();

	def update(self):
		logger = Logger.Logger()
		self.adjust_for_architecture();

	# 12 bytes on i386
	# 20 bytes on x64
	# most probably 2 pointers and 4 bytes of data
	def offset(self):
		logger = Logger.Logger()
		if self.sys_params.is_64_bit:
			return 20
		else:
			return 12

	def length(self):
		logger = Logger.Logger()
		size = self.valobj.CreateChildAtOffset("count",
							self.offset(),
							self.sys_params.types_cache.NSUInteger)
		return size.GetValueAsUnsigned(0)


class CFBagUnknown_SummaryProvider:
	def adjust_for_architecture(self):
		pass

	def __init__(self, valobj, params):
		logger = Logger.Logger()
		self.valobj = valobj;
		self.sys_params = params
		self.update();

	def update(self):
		logger = Logger.Logger()
		self.adjust_for_architecture();

	def length(self):
		logger = Logger.Logger()
		stream = lldb.SBStream()
		self.valobj.GetExpressionPath(stream)
		num_children_vo = self.valobj.CreateValueFromExpression("count","(int)CFBagGetCount(" + stream.GetData() + " )")
		if num_children_vo.IsValid():
			return num_children_vo.GetValueAsUnsigned(0)
		return "<variable is not CFBag>"


def GetSummary_Impl(valobj):
	logger = Logger.Logger()
	global statistics
	class_data,wrapper = objc_runtime.Utilities.prepare_class_detection(valobj,statistics)
	if wrapper:
		return wrapper
	
	name_string = class_data.class_name()
	actual_name = name_string
	
	logger >> "name string got was " + str(name_string) + " but actual name is " + str(actual_name)
	
	if class_data.is_cftype():
		# CFBag does not expose an actual NSWrapper type, so we have to check that this is
		# an NSCFType and then check we are a pointer-to __CFBag
		valobj_type = valobj.GetType()
		if valobj_type.IsValid() and valobj_type.IsPointerType():
			valobj_type = valobj_type.GetPointeeType()
			if valobj_type.IsValid():
				actual_name = valobj_type.GetName()
		if actual_name == '__CFBag' or \
		   actual_name == 'const struct __CFBag':
			wrapper = CFBagRef_SummaryProvider(valobj, class_data.sys_params)
			statistics.metric_hit('code_notrun',valobj)
			return wrapper
	wrapper = CFBagUnknown_SummaryProvider(valobj, class_data.sys_params)
	statistics.metric_hit('unknown_class',valobj.GetName() + " seen as " + actual_name)
	return wrapper;

def CFBag_SummaryProvider (valobj,dict):
	logger = Logger.Logger()
	provider = GetSummary_Impl(valobj);
	if provider != None:
		if isinstance(provider,objc_runtime.SpecialSituation_Description):
			return provider.message()
		try:
			summary = provider.length();
		except:
			summary = None
		logger >> "summary got from provider: " + str(summary)
		# for some reason, one needs to clear some bits for the count
		# to be correct when using CF(Mutable)BagRef on x64
		# the bit mask was derived through experimentation
		# (if counts start looking weird, then most probably
		#  the mask needs to be changed)
		if summary == None:
			summary = '<variable is not CFBag>'
		elif isinstance(summary,basestring):
			pass
		else:
			if provider.sys_params.is_64_bit:
				summary = summary & ~0x1fff000000000000
			if summary == 1:
				summary = '@"1 value"'
			else:
				summary = '@"' + str(summary) + ' values"'
		return summary
	return 'Summary Unavailable'

def __lldb_init_module(debugger,dict):
	debugger.HandleCommand("type summary add -F CFBag.CFBag_SummaryProvider CFBagRef CFMutableBagRef")