From 116231387eec9d71e9bf292886f6b51a5f78b867 Mon Sep 17 00:00:00 2001
From: Ryan Prichard <rprichard@google.com>
Date: Sat, 6 Apr 2024 01:29:14 -0700
Subject: Remove use of std::iterator and std::result_of

std::iterator was deprecated in C++17. std::result_of was removed in
C++20.

Bug: 333165689
Test: art_standalone_libartbase_tests
Change-Id: Id60f82a0368062416663a20d0b8e9a109fdac9cc
---
 libartbase/base/transform_array_ref.h   | 21 +++++++++------------
 libartbase/base/transform_iterator.h    |  2 +-
 runtime/native/dalvik_system_VMStack.cc |  6 ++----
 3 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/libartbase/base/transform_array_ref.h b/libartbase/base/transform_array_ref.h
index 9413b220db..6005596df8 100644
--- a/libartbase/base/transform_array_ref.h
+++ b/libartbase/base/transform_array_ref.h
@@ -33,15 +33,14 @@ class TransformArrayRef {
   using Iter = TransformIterator<typename ArrayRef<BaseType>::iterator, Function>;
 
   // The Function may take a non-const reference, so const_iterator may not exist.
-  using FallbackConstIter = std::iterator<std::random_access_iterator_tag, void, void, void, void>;
+  struct FallbackConstIter {
+    using pointer = void;
+    using reference = void;
+  };
   using PreferredConstIter =
       TransformIterator<typename ArrayRef<BaseType>::const_iterator, Function>;
-  template <typename F, typename = std::result_of_t<F(const BaseType&)>>
-  static PreferredConstIter ConstIterHelper(int&);
-  template <typename F>
-  static FallbackConstIter ConstIterHelper(const int&);
-
-  using ConstIter = decltype(ConstIterHelper<Function>(*reinterpret_cast<int*>(0)));
+  static constexpr bool kHasConstIter = std::is_invocable_v<Function, const BaseType&>;
+  using ConstIter = std::conditional_t<kHasConstIter, PreferredConstIter, FallbackConstIter>;
 
  public:
   using value_type = typename Iter::value_type;
@@ -50,12 +49,10 @@ class TransformArrayRef {
   using pointer = typename Iter::pointer;
   using const_pointer = typename ConstIter::pointer;
   using iterator = Iter;
-  using const_iterator =
-      std::conditional_t<std::is_same_v<ConstIter, FallbackConstIter>, void, ConstIter>;
+  using const_iterator = std::conditional_t<kHasConstIter, ConstIter, void>;
   using reverse_iterator = std::reverse_iterator<Iter>;
-  using const_reverse_iterator = std::conditional_t<std::is_same_v<ConstIter, FallbackConstIter>,
-                                                    void,
-                                                    std::reverse_iterator<ConstIter>>;
+  using const_reverse_iterator =
+      std::conditional_t<kHasConstIter, std::reverse_iterator<ConstIter>, void>;
   using difference_type = typename ArrayRef<BaseType>::difference_type;
   using size_type = typename ArrayRef<BaseType>::size_type;
 
diff --git a/libartbase/base/transform_iterator.h b/libartbase/base/transform_iterator.h
index 3f7c952b60..3da76f678e 100644
--- a/libartbase/base/transform_iterator.h
+++ b/libartbase/base/transform_iterator.h
@@ -47,7 +47,7 @@ class TransformIterator {
   using InputType = std::conditional_t<std::is_same_v<BaseReference, void>,
                                        typename std::iterator_traits<BaseIterator>::value_type,
                                        BaseReference>;
-  using ResultType = std::result_of_t<Function(InputType)>;
+  using ResultType = std::invoke_result_t<Function, InputType>;
 
  public:
   using iterator_category = typename std::iterator_traits<BaseIterator>::iterator_category;
diff --git a/runtime/native/dalvik_system_VMStack.cc b/runtime/native/dalvik_system_VMStack.cc
index 599bdb9e4b..366059bd17 100644
--- a/runtime/native/dalvik_system_VMStack.cc
+++ b/runtime/native/dalvik_system_VMStack.cc
@@ -36,10 +36,8 @@ namespace art HIDDEN {
 
 template <typename T,
           typename ResultT =
-              typename std::result_of<T(Thread*, const ScopedFastNativeObjectAccess&)>::type>
-static ResultT GetThreadStack(const ScopedFastNativeObjectAccess& soa,
-                              jobject peer,
-                              T fn)
+              typename std::invoke_result_t<T, Thread*, const ScopedFastNativeObjectAccess&>>
+static ResultT GetThreadStack(const ScopedFastNativeObjectAccess& soa, jobject peer, T fn)
     REQUIRES_SHARED(Locks::mutator_lock_) {
   ResultT trace = nullptr;
   ObjPtr<mirror::Object> decoded_peer = soa.Decode<mirror::Object>(peer);
-- 
cgit v1.2.3-59-g8ed1b