llvm-project/lldb/examples/summaries/cocoa/CFBag.py

"""
LLDB AppKit formatters

Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
See https://llvm.org/LICENSE.txt for license information.
SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
"""
# example summary provider for CFBag
# the real summary is now C++ code built into LLDB
import lldb
import ctypes
import lldb.runtime.objc.objc_runtime
import lldb.formatters.metrics
import lldb.formatters.Logger

try:
    basestring
except NameError:
    basestring = str

statistics = lldb.formatters.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 = lldb.formatters.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 = lldb.formatters.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 = lldb.formatters.Logger.Logger()
        if self.sys_params.is_64_bit:
            return 20
        else:
            return 12

    def length(self):
        logger = lldb.formatters.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 = lldb.formatters.Logger.Logger()
        self.valobj = valobj
        self.sys_params = params
        self.update()

    def update(self):
        logger = lldb.formatters.Logger.Logger()
        self.adjust_for_architecture()

    def length(self):
        logger = lldb.formatters.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 = lldb.formatters.Logger.Logger()
    global statistics
    class_data, wrapper = lldb.runtime.objc.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 = lldb.formatters.Logger.Logger()
    provider = GetSummary_Impl(valobj)
    if provider is not None:
        if isinstance(
                provider,
                lldb.runtime.objc.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 is 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")