From 10ec28c5de9442fe93635ae76ca397d138f9e93c Mon Sep 17 00:00:00 2001
From: Steven Le Rouzic <steven.lerouzic@gmail.com>
Date: Sat, 13 Apr 2024 01:41:13 +0200
Subject: Add atomics

---
 deimos/core/status.cpp | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

(limited to 'deimos/core/status.cpp')

diff --git a/deimos/core/status.cpp b/deimos/core/status.cpp
index ed1a665..f472aac 100644
--- a/deimos/core/status.cpp
+++ b/deimos/core/status.cpp
@@ -2,12 +2,20 @@
 
 #include "deimos/core/api_registry.h"
 #include "deimos/core/allocator.h"
+#include "deimos/core/atomic.h"
 
 static deimos::AllocatorApi* allocator_api;
 
 namespace deimos
 {
 
+struct StatusRep
+{
+    Atomic<int32_t>             ref_count;
+    StatusCode                  code{};
+    StringView                  message;
+};
+
 Status::Status(StatusCode code, StringView message)
 {
     if (code == StatusCode::kOk)
@@ -23,7 +31,7 @@ Status::Status(StatusCode code, StringView message)
         MemoryCopy(message_ptr, message.data(), message.size());
         message_ptr[message.size()] = '\0'; // NOLINT
 
-        rep->ref_count = 1;
+        AtomicStore(&rep->ref_count, 1);
         rep->code = code;
         rep->message = StringView(message_ptr, message.size());
 
@@ -38,22 +46,27 @@ void Status::Ref() const
     {
         auto* rep = std::bit_cast<StatusRep*>(m_rep);
 
-        Expects(rep->ref_count > 0);
-        rep->ref_count += 1;
+        Expects(AtomicLoad(&rep->ref_count) > 0);
+        AtomicFetchIncrement(&rep->ref_count);
     }
 }
 
+StatusCode Status::RepCode() const
+{
+    Expects(!IsInline());
+    return std::bit_cast<StatusRep*>(m_rep)->code;
+}
+
 void Status::Unref() const
 {
     if (!IsInline())
     {
         auto* rep = std::bit_cast<StatusRep*>(m_rep);
 
-        Expects(rep->ref_count > 0);
-        rep->ref_count -= 1;
-
-        if (rep->ref_count == 0)
+        Expects(AtomicLoad(&rep->ref_count) > 0);
+        if (AtomicFetchDecrement(&rep->ref_count, MemoryOrder::kRelease) == 1)
         {
+            AtomicFence(MemoryOrder::kAcquire);
             deimos_StaticAssert(std::is_trivially_destructible_v<StatusRep>);
             allocator_api->system->Free(
                 rep, (int64_t)sizeof(StatusRep) + rep->message.size() + 1);
-- 
cgit