From 93fd55249b8f097e283f14420d55f23adbd2836b Mon Sep 17 00:00:00 2001
From: hubslave <29800872+hubslave@users.noreply.github.com>
Date: Fri, 2 Mar 2018 18:15:45 +0200
Subject: [PATCH] Fix build on platforms without std::string_view

json.hpp wants it, but it isn't always available. Rather than patch
json.hpp directly to remove the dependency, provide a json.h wrapper
header that subs in std::experimental::string_view using preprocessor
magic. All the consumers of json.hpp are in src/web_service, so the
wrapper header is placed there as well.
---
 src/web_service/announce_room_json.cpp |  2 +-
 src/web_service/json.h                 | 18 ++++++++++++++++++
 src/web_service/telemetry_json.h       |  2 +-
 src/web_service/verify_login.cpp       |  2 +-
 4 files changed, 21 insertions(+), 3 deletions(-)
 create mode 100644 src/web_service/json.h

diff --git a/src/web_service/announce_room_json.cpp b/src/web_service/announce_room_json.cpp
index d2b79cbae..87f9327bb 100644
--- a/src/web_service/announce_room_json.cpp
+++ b/src/web_service/announce_room_json.cpp
@@ -3,9 +3,9 @@
 // Refer to the license.txt file included.
 
 #include <future>
-#include <json.hpp>
 #include "common/logging/log.h"
 #include "web_service/announce_room_json.h"
+#include "web_service/json.h"
 #include "web_service/web_backend.h"
 
 namespace AnnounceMultiplayerRoom {
diff --git a/src/web_service/json.h b/src/web_service/json.h
new file mode 100644
index 000000000..88b31501e
--- /dev/null
+++ b/src/web_service/json.h
@@ -0,0 +1,18 @@
+// Copyright 2018 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+// This hack is needed to support json.hpp on platforms where the C++17 stdlib
+// lacks std::string_view. See https://github.com/nlohmann/json/issues/735.
+// clang-format off
+#if !__has_include(<string_view>) && __has_include(<experimental/string_view>)
+# include <experimental/string_view>
+# define string_view experimental::string_view
+# include <json.hpp>
+# undef string_view
+#else
+# include <json.hpp>
+#endif
+// clang-format on
diff --git a/src/web_service/telemetry_json.h b/src/web_service/telemetry_json.h
index ae4a6f3c7..27f71b6ba 100644
--- a/src/web_service/telemetry_json.h
+++ b/src/web_service/telemetry_json.h
@@ -7,9 +7,9 @@
 #include <array>
 #include <future>
 #include <string>
-#include <json.hpp>
 #include "common/announce_multiplayer_room.h"
 #include "common/telemetry.h"
+#include "web_service/json.h"
 
 namespace WebService {
 
diff --git a/src/web_service/verify_login.cpp b/src/web_service/verify_login.cpp
index 1bc3b5afe..05082a309 100644
--- a/src/web_service/verify_login.cpp
+++ b/src/web_service/verify_login.cpp
@@ -2,7 +2,7 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
-#include <json.hpp>
+#include "web_service/json.h"
 #include "web_service/verify_login.h"
 #include "web_service/web_backend.h"