From 6050e2ac8f34e5be90ce5e2f73fdcd7971adf32c Mon Sep 17 00:00:00 2001
From: Maksym Malyhin <mmaksym@google.com>
Date: Tue, 13 Jul 2021 10:24:46 -0400
Subject: [PATCH] Ues __extension__ to make runtime availability check

---
 GoogleUtilities/Logger/GULSignpostLogger.m    | 10 +++--
 .../GoogleUtilities/GULSignpostLogger.h       | 39 +++++++++++++------
 2 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/GoogleUtilities/Logger/GULSignpostLogger.m b/GoogleUtilities/Logger/GULSignpostLogger.m
index 486192d..70fcbc7 100644
--- a/GoogleUtilities/Logger/GULSignpostLogger.m
+++ b/GoogleUtilities/Logger/GULSignpostLogger.m
@@ -18,10 +18,14 @@ gul_os_log_t _gul_default_signpost_log(void) {
   return _default_signpost_log;
 }
 
-void _gul_os_signpost_interval_begin(gul_os_log_t log, gul_os_signpost_id_t interval_id, const char *name, ...) {
+gul_os_signpost_id_t gul_os_signpost_id_generate(gul_os_log_t log) {
+#if __has_include(<os/signpost.h>)
   if (@available(iOS 12.0, *)) {
-    os_signpost_interval_begin(log, interval_id, name, "" __VA_ARGS__);
+    return os_signpost_id_generate(log);
   } else {
-    // Fallback on earlier versions
+    return 0;
   }
+#else // __has_include(<os/signpost.h>)
+  return 0;
+#endif // __has_include(<os/signpost.h>)
 }
diff --git a/GoogleUtilities/Logger/Public/GoogleUtilities/GULSignpostLogger.h b/GoogleUtilities/Logger/Public/GoogleUtilities/GULSignpostLogger.h
index 689f713..5fbea08 100644
--- a/GoogleUtilities/Logger/Public/GoogleUtilities/GULSignpostLogger.h
+++ b/GoogleUtilities/Logger/Public/GoogleUtilities/GULSignpostLogger.h
@@ -13,36 +13,50 @@
 typedef os_log_t gul_os_log_t;
 typedef os_signpost_id_t gul_os_signpost_id_t;
 
-// See `os_signpost_id_generate`.
-#define gul_os_signpost_id_generate(log) \
-  os_signpost_id_generate(log)
-
 // See `os_signpost_interval_begin`.
 #define gul_os_signpost_interval_begin(log, interval_id, name, ...) \
- _gul_os_signpost_interval_begin(log, interval_id, name, ##__VA_ARGS__)
+    __extension__({ \
+        if (@available(iOS 12.0, *)) { \
+          os_signpost_interval_begin(log, interval_id, name, "" __VA_ARGS__); \
+        } \
+    })
 
 // See `os_signpost_interval_end`.
 #define gul_os_signpost_interval_end(log, interval_id, name, ...) \
-  os_signpost_interval_end(log, interval_id, name, ##__VA_ARGS__)
+    __extension__({ \
+        if (@available(iOS 12.0, *)) { \
+          os_signpost_interval_end(log, interval_id, name, "" __VA_ARGS__); \
+        } \
+    })
 
 // See `os_signpost_interval_end`.
 #define gul_os_signpost_interval_emit(log, event_id, name, ...) \
-  os_signpost_interval_emit(log, event_id, name, ##__VA_ARGS__)
+    __extension__({ \
+        if (@available(iOS 12.0, *)) { \
+          os_signpost_interval_end(log, event_id, name, "" __VA_ARGS__); \
+        } \
+    })
 
 // See `_gul_default_signpost_log`.
 #define gul_default_signpost_log() \
   _gul_default_signpost_log()
 
+
+#define _gul_os_signpost_interval_begin(log, interval_id, name, ...) \
+    __extension__({ \
+        if (@available(iOS 12.0, *)) { \
+          os_signpost_interval_begin(log, interval_id, name, "" __VA_ARGS__); \
+        } \
+    })
+
 #else // __has_include(<os/signpost.h>)
 
 // Placeholders for the signpost API methods and types when it's not available.
 
 typedef void gul_os_log_t;
-typedef void gul_os_signpost_id_t;
+typedef uint64_t gul_os_signpost_id_t;
 
-#define gul_os_signpost_id_generate(log)
-
-//#define gul_os_signpost_interval_begin(log, interval_id, name, ...)
+#define gul_os_signpost_interval_begin(log, interval_id, name, ...)
 
 #define gul_os_signpost_interval_end(log, interval_id, name, ...)
 
@@ -56,4 +70,5 @@ typedef void gul_os_signpost_id_t;
 /// @return A default instance of `gul_os_log_t`.
 gul_os_log_t _gul_default_signpost_log(void);
 
-void _gul_os_signpost_interval_begin(gul_os_log_t log, gul_os_signpost_id_t interval_id, const char *name, ...);
+// See `os_signpost_id_generate`.
+gul_os_signpost_id_t gul_os_signpost_id_generate(gul_os_log_t log);