1 //===-- LibCxxQueue.cpp ---------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "LibCxx.h"
10 #include "lldb/DataFormatters/FormattersHelpers.h"
11 
12 using namespace lldb;
13 using namespace lldb_private;
14 
15 namespace {
16 
17 class QueueFrontEnd : public SyntheticChildrenFrontEnd {
18 public:
QueueFrontEnd(ValueObject & valobj)19   QueueFrontEnd(ValueObject &valobj) : SyntheticChildrenFrontEnd(valobj) {
20     Update();
21   }
22 
GetIndexOfChildWithName(ConstString name)23   size_t GetIndexOfChildWithName(ConstString name) override {
24     return m_container_sp ? m_container_sp->GetIndexOfChildWithName(name)
25                           : UINT32_MAX;
26   }
27 
MightHaveChildren()28   bool MightHaveChildren() override { return true; }
29   bool Update() override;
30 
CalculateNumChildren()31   size_t CalculateNumChildren() override {
32     return m_container_sp ? m_container_sp->GetNumChildren() : 0;
33   }
34 
GetChildAtIndex(size_t idx)35   ValueObjectSP GetChildAtIndex(size_t idx) override {
36     return m_container_sp ? m_container_sp->GetChildAtIndex(idx, true)
37                           : nullptr;
38   }
39 
40 private:
41   // The lifetime of a ValueObject and all its derivative ValueObjects
42   // (children, clones, etc.) is managed by a ClusterManager. These
43   // objects are only destroyed when every shared pointer to any of them
44   // is destroyed, so we must not store a shared pointer to any ValueObject
45   // derived from our backend ValueObject (since we're in the same cluster).
46   ValueObject* m_container_sp = nullptr;
47 };
48 } // namespace
49 
Update()50 bool QueueFrontEnd::Update() {
51   m_container_sp = nullptr;
52   ValueObjectSP c_sp = m_backend.GetChildMemberWithName(ConstString("c"), true);
53   if (!c_sp)
54     return false;
55   m_container_sp = c_sp->GetSyntheticValue().get();
56   return false;
57 }
58 
59 SyntheticChildrenFrontEnd *
LibcxxQueueFrontEndCreator(CXXSyntheticChildren *,lldb::ValueObjectSP valobj_sp)60 formatters::LibcxxQueueFrontEndCreator(CXXSyntheticChildren *,
61                                        lldb::ValueObjectSP valobj_sp) {
62   if (valobj_sp)
63     return new QueueFrontEnd(*valobj_sp);
64   return nullptr;
65 }
66