From 00b9b89bdd1db70b31079a5cf9b96c778c2af26a Mon Sep 17 00:00:00 2001
From: RobinTF <83676088+RobinTF@users.noreply.github.com>
Date: Tue, 12 Nov 2024 00:47:16 +0100
Subject: [PATCH] Provide own version of owning view

---
 src/engine/CartesianProductJoin.cpp |  3 +-
 src/util/OwningView.h               | 82 +++++++++++++++++++++++++++++
 2 files changed, 84 insertions(+), 1 deletion(-)
 create mode 100644 src/util/OwningView.h

diff --git a/src/engine/CartesianProductJoin.cpp b/src/engine/CartesianProductJoin.cpp
index f3f9e07020..0ccd465a97 100644
--- a/src/engine/CartesianProductJoin.cpp
+++ b/src/engine/CartesianProductJoin.cpp
@@ -5,6 +5,7 @@
 #include "engine/CartesianProductJoin.h"
 
 #include "engine/CallFixedSize.h"
+#include "util/OwningView.h"
 
 // ____________________________________________________________________________
 CartesianProductJoin::CartesianProductJoin(
@@ -157,7 +158,7 @@ ProtoResult CartesianProductJoin::computeResult(bool requestLaziness) {
 
   // Owning view wrapper to please gcc 11.
   return {produceTablesLazily(std::move(staticMergedVocab),
-                              std::ranges::owning_view{std::move(subResults)} |
+                              owning_view{std::move(subResults)} |
                                   std::views::transform(&Result::idTable),
                               getLimit()._offset, getLimit().limitOrDefault()),
           resultSortedOn()};
diff --git a/src/util/OwningView.h b/src/util/OwningView.h
new file mode 100644
index 0000000000..984b2d85da
--- /dev/null
+++ b/src/util/OwningView.h
@@ -0,0 +1,82 @@
+//   Copyright 2024, University of Freiburg,
+//   Chair of Algorithms and Data Structures.
+//   Author: Robin Textor-Falconi <textorr@informatik.uni-freiburg.de>
+
+#pragma once
+
+#include <ranges>
+
+// Implementation of std::ranges::owning_view for gcc 11.
+#if __GNUC__ == 11
+#include "util/TypeTraits.h"
+
+template <std::ranges::range R>
+requires std::movable<R> &&
+         (!ad_utility::isInstantiation<std::remove_cv_t<R>,
+                                       std::initializer_list>)class owning_view
+    : public std::ranges::view_interface<owning_view<R>> {
+ private:
+  R range_ = R();
+
+ public:
+  owning_view() requires std::default_initializable<R> = default;
+
+  constexpr owning_view(R&& r) noexcept(std::is_nothrow_move_constructible_v<R>)
+      : range_(std::move(r)) {}
+
+  owning_view(owning_view&&) = default;
+  owning_view& operator=(owning_view&&) = default;
+
+  constexpr R& base() & noexcept { return range_; }
+
+  constexpr const R& base() const& noexcept { return range_; }
+
+  constexpr R&& base() && noexcept { return std::move(range_); }
+
+  constexpr const R&& base() const&& noexcept { return std::move(range_); }
+
+  constexpr std::ranges::iterator_t<R> begin() {
+    return std::ranges::begin(range_);
+  }
+
+  constexpr std::ranges::sentinel_t<R> end() {
+    return std::ranges::end(range_);
+  }
+
+  constexpr auto begin() const requires std::ranges::range<const R> {
+    return std::ranges::begin(range_);
+  }
+
+  constexpr auto end() const requires std::ranges::range<const R> {
+    return std::ranges::end(range_);
+  }
+
+  constexpr bool empty() requires requires { std::ranges::empty(range_); } {
+    return std::ranges::empty(range_);
+  }
+
+  constexpr bool empty() const requires requires { std::ranges::empty(range_); }
+  {
+    return std::ranges::empty(range_);
+  }
+
+  constexpr auto size() requires std::ranges::sized_range<R> {
+    return std::ranges::size(range_);
+  }
+
+  constexpr auto size() const requires std::ranges::sized_range<const R> {
+    return std::ranges::size(range_);
+  }
+
+  constexpr auto data() requires std::ranges::contiguous_range<R> {
+    return std::ranges::data(range_);
+  }
+
+  constexpr auto data() const requires std::ranges::contiguous_range<const R> {
+    return std::ranges::data(range_);
+  }
+};
+#else
+template <std::ranges::range R>
+using owning_view = std::ranges::owning_view<R>;
+#endif