From 8a71039475212fb1e1a6dd2fd2911d02769637ef Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Thu, 8 Apr 2021 21:10:30 -0700
Subject: Improve robustness of gfx lifetime management. (#1788)

* Improve robustness of gfx lifetime management.

* fix clang error

* fix clang error

* Fix clang warning
---
 source/core/slang-com-object.h | 70 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 source/core/slang-com-object.h

(limited to 'source/core/slang-com-object.h')

diff --git a/source/core/slang-com-object.h b/source/core/slang-com-object.h
new file mode 100644
index 000000000..ad4578585
--- /dev/null
+++ b/source/core/slang-com-object.h
@@ -0,0 +1,70 @@
+#ifndef SLANG_COM_OBJECT_H
+#define SLANG_COM_OBJECT_H
+
+#include "slang-basic.h"
+#include <atomic>
+
+namespace Slang
+{
+class ComObject : public RefObject
+{
+protected:
+    std::atomic<uint32_t> comRefCount;
+
+public:
+    ComObject()
+        : comRefCount(0)
+    {}
+    ComObject(const ComObject&) : comRefCount(0) {}
+    ComObject& operator=(const ComObject&)
+    {
+        comRefCount = 0;
+        return *this;
+    };
+    virtual void comFree() {}
+
+    uint32_t addRefImpl()
+    {
+        auto oldRefCount = comRefCount++;
+        if (oldRefCount == 0)
+            addReference();
+        return oldRefCount + 1;
+    }
+
+    uint32_t releaseImpl()
+    {
+        auto oldRefCount = comRefCount--;
+        if (oldRefCount == 1)
+        {
+            comFree();
+            releaseReference();
+        }
+        return oldRefCount - 1;
+    }
+};
+
+#define SLANG_COM_OBJECT_IUNKNOWN_QUERY_INTERFACE                                                  \
+    SLANG_NO_THROW SlangResult SLANG_MCALL queryInterface(SlangUUID const& uuid, void** outObject) \
+        SLANG_OVERRIDE                                                                             \
+    {                                                                                              \
+        void* intf = getInterface(uuid);                                                           \
+        if (intf)                                                                                  \
+        {                                                                                          \
+            addRef();                                                                              \
+            *outObject = intf;                                                                     \
+            return SLANG_OK;                                                                       \
+        }                                                                                          \
+        return SLANG_E_NO_INTERFACE;                                                               \
+    }
+#define SLANG_COM_OBJECT_IUNKNOWN_ADD_REF \
+    SLANG_NO_THROW uint32_t SLANG_MCALL addRef() SLANG_OVERRIDE { return addRefImpl(); }
+#define SLANG_COM_OBJECT_IUNKNOWN_RELEASE \
+    SLANG_NO_THROW uint32_t SLANG_MCALL release() SLANG_OVERRIDE { return releaseImpl(); }
+#define SLANG_COM_OBJECT_IUNKNOWN_ALL         \
+    SLANG_COM_OBJECT_IUNKNOWN_QUERY_INTERFACE \
+    SLANG_COM_OBJECT_IUNKNOWN_ADD_REF         \
+    SLANG_COM_OBJECT_IUNKNOWN_RELEASE
+
+} // namespace Slang
+
+#endif
-- 
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