From 11f334121fd0d13830fefdf08041183da2d30ef3 Mon Sep 17 00:00:00 2001
From: Peter Kasting <pkasting@chromium.org>
Date: Thu, 8 Aug 2024 11:04:47 -0700
Subject: [PATCH] [jumbo] Mark Span and Input as satisfying view and
 borrowed_range.

These concepts are appropriate for these types, and we also enable them
for e.g. base::span.

This is necessary for Chromium to annotate more base::span constructors
with LIFETIMEBOUND without producing false positive warnings with these
types. It only has an effect under C++20 (but should preprocess away to
nothing on older C++ versions).

Bug: none
Change-Id: Ib2b8cba4b7bd2d5028ce27de4fd9c44fca7d5560
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/70068
Reviewed-by: David Benjamin <davidben@google.com>
Auto-Submit: Peter Kasting <pkasting@google.com>
---
 include/openssl/span.h | 22 ++++++++++++++++++++++
 pki/input.h            | 22 ++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/include/openssl/span.h b/include/openssl/span.h
index 4f11559e7..a6cd5b7a1 100644
--- a/include/openssl/span.h
+++ b/include/openssl/span.h
@@ -30,6 +30,28 @@ extern "C++" {
 #include <string_view>
 #endif
 
+#if defined(__has_include)
+#if __has_include(<version>)
+#include <version>
+#endif
+#endif
+
+#if defined(__cpp_lib_ranges) && __cpp_lib_ranges >= 201911L
+#include <ranges>
+BSSL_NAMESPACE_BEGIN
+template <typename T>
+class Span;
+BSSL_NAMESPACE_END
+
+// Mark `Span` as satisfying the `view` and `borrowed_range` concepts. This
+// should be done before the definition of `Span`, so that any inlined calls to
+// range functionality use the correct specializations.
+template <typename T>
+inline constexpr bool std::ranges::enable_view<bssl::Span<T>> = true;
+template <typename T>
+inline constexpr bool std::ranges::enable_borrowed_range<bssl::Span<T>> = true;
+#endif
+
 BSSL_NAMESPACE_BEGIN
 
 template <typename T>
diff --git a/pki/input.h b/pki/input.h
index 6ed79d9e0..15bdbd62e 100644
--- a/pki/input.h
+++ b/pki/input.h
@@ -14,6 +14,28 @@
 #include <openssl/base.h>
 #include <openssl/span.h>
 
+#if defined(__has_include)
+#if __has_include(<version>)
+#include <version>
+#endif
+#endif
+
+#if defined(__cpp_lib_ranges) && __cpp_lib_ranges >= 201911L
+#include <ranges>
+namespace bssl::der {
+class OPENSSL_EXPORT Input;
+}
+
+// Mark `Input` as satisfying the `view` and `borrowed_range` concepts. This
+// should be done before the definition of `Input`, so that any inlined calls to
+// range functionality use the correct specializations.
+template <>
+inline constexpr bool std::ranges::enable_view<bssl::der::Input> = true;
+template <>
+inline constexpr bool std::ranges::enable_borrowed_range<bssl::der::Input> =
+    true;
+#endif
+
 namespace bssl::der {
 
 // An opaque class that represents a fixed buffer of data of a fixed length,