"""Helper library to traverse data emitted for Rust enums """
from lldbsuite.test.lldbtest import *
DISCRIMINANT_MEMBER_NAME = "$discr$"
VALUE_MEMBER_NAME = "value"
class RustEnumValue:
def __init__(self, value: lldb.SBValue):
self.value = value
def getAllVariantTypes(self):
result = []
for i in range(self._inner().GetNumChildren()):
result.append(self.getVariantByIndex(i).GetDisplayTypeName())
return result
def _inner(self) -> lldb.SBValue:
return self.value.GetChildAtIndex(0)
def getVariantByIndex(self, index):
return (
self._inner()
.GetChildAtIndex(index)
.GetChildMemberWithName(VALUE_MEMBER_NAME)
)
@staticmethod
def _getDiscriminantValueAsUnsigned(discr_sbvalue: lldb.SBValue):
byte_size = discr_sbvalue.GetType().GetByteSize()
error = lldb.SBError()
# when discriminant is u16 Clang emits 'unsigned char'
# and LLDB seems to treat it as character type disalowing to call GetValueAsUnsigned
if byte_size == 1:
return discr_sbvalue.GetData().GetUnsignedInt8(error, 0)
elif byte_size == 2:
return discr_sbvalue.GetData().GetUnsignedInt16(error, 0)
elif byte_size == 4:
return discr_sbvalue.GetData().GetUnsignedInt32(error, 0)
elif byte_size == 8:
return discr_sbvalue.GetData().GetUnsignedInt64(error, 0)
else:
return discr_sbvalue.GetValueAsUnsigned()
def getCurrentVariantIndex(self):
default_index = 0
for i in range(self._inner().GetNumChildren()):
variant: lldb.SBValue = self._inner().GetChildAtIndex(i)
discr = variant.GetChildMemberWithName(DISCRIMINANT_MEMBER_NAME)
if discr.IsValid():
discr_unsigned_value = RustEnumValue._getDiscriminantValueAsUnsigned(
discr
)
if variant.GetName() == f"$variant${discr_unsigned_value}":
return discr_unsigned_value
else:
default_index = i
return default_index
def getFields(self):
result = []
for i in range(self._inner().GetNumChildren()):
type: lldb.SBType = self._inner().GetType()
result.append(type.GetFieldAtIndex(i).GetName())
return result
def getCurrentValue(self) -> lldb.SBValue:
return self.getVariantByIndex(self.getCurrentVariantIndex())