| //===-- LibCxxOptional.cpp ------------------------------------------------===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "LibCxx.h" |
| #include "lldb/DataFormatters/FormattersHelpers.h" |
| |
| using namespace lldb; |
| using namespace lldb_private; |
| |
| namespace { |
| |
| class OptionalFrontEnd : public SyntheticChildrenFrontEnd { |
| public: |
| OptionalFrontEnd(ValueObject &valobj) : SyntheticChildrenFrontEnd(valobj) { |
| Update(); |
| } |
| |
| size_t GetIndexOfChildWithName(ConstString name) override { |
| return formatters::ExtractIndexFromString(name.GetCString()); |
| } |
| |
| bool MightHaveChildren() override { return true; } |
| bool Update() override; |
| size_t CalculateNumChildren() override { return m_has_value ? 1U : 0U; } |
| ValueObjectSP GetChildAtIndex(size_t idx) override; |
| |
| private: |
| /// True iff the option contains a value. |
| bool m_has_value = false; |
| }; |
| } // namespace |
| |
| bool OptionalFrontEnd::Update() { |
| ValueObjectSP engaged_sp( |
| m_backend.GetChildMemberWithName(ConstString("__engaged_"), true)); |
| |
| if (!engaged_sp) |
| return false; |
| |
| // __engaged_ is a bool flag and is true if the optional contains a value. |
| // Converting it to unsigned gives us a size of 1 if it contains a value |
| // and 0 if not. |
| m_has_value = engaged_sp->GetValueAsUnsigned(0) == 1; |
| |
| return false; |
| } |
| |
| ValueObjectSP OptionalFrontEnd::GetChildAtIndex(size_t idx) { |
| if (!m_has_value) |
| return ValueObjectSP(); |
| |
| // __val_ contains the underlying value of an optional if it has one. |
| // Currently because it is part of an anonymous union GetChildMemberWithName() |
| // does not peer through and find it unless we are at the parent itself. |
| // We can obtain the parent through __engaged_. |
| ValueObjectSP val_sp( |
| m_backend.GetChildMemberWithName(ConstString("__engaged_"), true) |
| ->GetParent() |
| ->GetChildAtIndex(0, true) |
| ->GetChildMemberWithName(ConstString("__val_"), true)); |
| |
| if (!val_sp) |
| return ValueObjectSP(); |
| |
| CompilerType holder_type = val_sp->GetCompilerType(); |
| |
| if (!holder_type) |
| return ValueObjectSP(); |
| |
| return val_sp->Clone(ConstString("Value")); |
| } |
| |
| SyntheticChildrenFrontEnd * |
| formatters::LibcxxOptionalFrontEndCreator(CXXSyntheticChildren *, |
| lldb::ValueObjectSP valobj_sp) { |
| if (valobj_sp) |
| return new OptionalFrontEnd(*valobj_sp); |
| return nullptr; |
| } |