Add data formatter for libc++ std::queue

Summary:
std::queue is just a fancy wrapper around another container, so all we
need to do is to delegate to the it.

Reviewers: jingham, EricWF

Subscribers: srhines, mgorny, lldb-commits, eugene

Differential Revision: https://reviews.llvm.org/D35666

llvm-svn: 317099

1 files changed, 61 insertions, 0 deletions

diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxxQueue.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxxQueue.cpp
new file mode 100644
index 00000000000..c4e0b66d427
--- /dev/null
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxxQueue.cpp
@@ -0,0 +1,61 @@
+//===-- LibCxxQueue.cpp -----------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "LibCxx.h"
+#include "lldb/DataFormatters/FormattersHelpers.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+namespace {
+
+class QueueFrontEnd : public SyntheticChildrenFrontEnd {
+public:
+  QueueFrontEnd(ValueObject &valobj) : SyntheticChildrenFrontEnd(valobj) {
+    Update();
+  }
+
+  size_t GetIndexOfChildWithName(const ConstString &name) override {
+    return m_container_sp ? m_container_sp->GetIndexOfChildWithName(name)
+                          : UINT32_MAX;
+  }
+
+  bool MightHaveChildren() override { return true; }
+  bool Update() override;
+
+  size_t CalculateNumChildren() override {
+    return m_container_sp ? m_container_sp->GetNumChildren() : 0;
+  }
+
+  ValueObjectSP GetChildAtIndex(size_t idx) override {
+    return m_container_sp ? m_container_sp->GetChildAtIndex(idx, true)
+                          : nullptr;
+  }
+
+private:
+  ValueObjectSP m_container_sp;
+};
+} // namespace
+
+bool QueueFrontEnd::Update() {
+  m_container_sp.reset();
+  ValueObjectSP c_sp = m_backend.GetChildMemberWithName(ConstString("c"), true);
+  if (!c_sp)
+    return false;
+  m_container_sp = c_sp->GetSyntheticValue();
+  return false;
+}
+
+SyntheticChildrenFrontEnd *
+formatters::LibcxxQueueFrontEndCreator(CXXSyntheticChildren *,
+                                       lldb::ValueObjectSP valobj_sp) {
+  if (valobj_sp)
+    return new QueueFrontEnd(*valobj_sp);
+  return nullptr;
+}