//===-- LibStdcppTuple.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 "LibStdcpp.h"

#include "lldb/Core/ValueObject.h"

#include "lldb/DataFormatters/FormattersHelpers.h"

#include "lldb/DataFormatters/TypeSynthetic.h"

#include "lldb/Utility/ConstString.h"

#include <memory>

#include <vector>

using namespace lldb;

using namespace lldb_private;

using namespace lldb_private::formatters;

namespace {

class LibStdcppTupleSyntheticFrontEnd : public SyntheticChildrenFrontEnd {

public:

  explicit LibStdcppTupleSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);

  size_t CalculateNumChildren() override;

  lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;

  bool Update() override;

  bool MightHaveChildren() override;

  size_t GetIndexOfChildWithName(ConstString name) override;

private:

  // The lifetime of a ValueObject and all its derivative ValueObjects

  // (children, clones, etc.) is managed by a ClusterManager. These

  // objects are only destroyed when every shared pointer to any of them

  // is destroyed, so we must not store a shared pointer to any ValueObject

  // derived from our backend ValueObject (since we're in the same cluster).

  std::vector<ValueObject*> m_members;

};

} // end of anonymous namespace

LibStdcppTupleSyntheticFrontEnd::LibStdcppTupleSyntheticFrontEnd(

    lldb::ValueObjectSP valobj_sp)

    : SyntheticChildrenFrontEnd(*valobj_sp) {

  Update();

}

bool LibStdcppTupleSyntheticFrontEnd::Update() {

  m_members.clear();

  ValueObjectSP valobj_backend_sp = m_backend.GetSP();

  if (!valobj_backend_sp)

    return false;

  ValueObjectSP next_child_sp = valobj_backend_sp->GetNonSyntheticValue();

  while (next_child_sp != nullptr) {

    ValueObjectSP current_child = next_child_sp;

    next_child_sp = nullptr;

    size_t child_count = current_child->GetNumChildren();

    for (size_t i = 0; i < child_count; ++i) {

      ValueObjectSP child_sp = current_child->GetChildAtIndex(i);

      llvm::StringRef name_str = child_sp->GetName().GetStringRef();

      if (name_str.startswith("std::_Tuple_impl<")) {

        next_child_sp = child_sp;

      } else if (name_str.startswith("std::_Head_base<")) {

        ValueObjectSP value_sp =

            child_sp->GetChildMemberWithName("_M_head_impl");

        if (value_sp) {

          StreamString name;

          name.Printf("[%zd]", m_members.size());

          m_members.push_back(value_sp->Clone(ConstString(name.GetString())).get());

        }

      }

    }

  }

  return false;

}

bool LibStdcppTupleSyntheticFrontEnd::MightHaveChildren() { return true; }

lldb::ValueObjectSP

LibStdcppTupleSyntheticFrontEnd::GetChildAtIndex(size_t idx) {

  if (idx < m_members.size() && m_members[idx])

    return m_members[idx]->GetSP();

  return lldb::ValueObjectSP();

}

size_t LibStdcppTupleSyntheticFrontEnd::CalculateNumChildren() {

  return m_members.size();

}

size_t LibStdcppTupleSyntheticFrontEnd::GetIndexOfChildWithName(

    ConstString name) {

  return ExtractIndexFromString(name.GetCString());

}

SyntheticChildrenFrontEnd *

lldb_private::formatters::LibStdcppTupleSyntheticFrontEndCreator(

    CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {

  return (valobj_sp ? new LibStdcppTupleSyntheticFrontEnd(valobj_sp) : nullptr);

}