From dc48c5debd8f2e77aa52e39576d957cd33fb888e Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Thu, 15 Apr 2021 08:53:44 +0800
Subject: [PATCH] Base: improve class 'Handle' efficiency

By replacing dynamic allocated QAtomicInt with std::atomic and making
most code inlined.
---
 src/Base/Handle.cpp | 42 -----------------------------------
 src/Base/Handle.h   | 53 +++++++++++++++++++++++++++++++++++----------
 2 files changed, 41 insertions(+), 54 deletions(-)

diff --git a/src/Base/Handle.cpp b/src/Base/Handle.cpp
index c02189b83f..5202530ffd 100644
--- a/src/Base/Handle.cpp
+++ b/src/Base/Handle.cpp
@@ -25,52 +25,10 @@
 #include "PreCompiled.h"
 
 #ifndef _PreComp_
-# include <cassert>
-# include <iostream>
 #endif
 
-#include <QAtomicInt>
-
 #include "Handle.h"
 
 
 using namespace Base;
 
-//**************************************************************************
-// Construction/Destruction
-
-Handled::Handled()
-  : _lRefCount(new QAtomicInt(0))
-{
-}
-
-Handled::~Handled()
-{
-    if (static_cast<int>(*_lRefCount) != 0)
-        std::cerr << "Reference counter of deleted object is not zero!!!!!" << std::endl;
-    delete _lRefCount;
-}
-
-void Handled::ref() const
-{
-    _lRefCount->ref();
-}
-
-void Handled::unref() const
-{
-    assert(*_lRefCount > 0);
-    if (!_lRefCount->deref()) {
-        delete this;
-    }
-}
-
-int Handled::getRefCount() const
-{
-    return static_cast<int>(*_lRefCount);
-}
-
-const Handled& Handled::operator = (const Handled&)
-{
-    // we must not assign _lRefCount
-    return *this;
-}
diff --git a/src/Base/Handle.h b/src/Base/Handle.h
index c3e05ffb80..2e2ad6fe8a 100644
--- a/src/Base/Handle.h
+++ b/src/Base/Handle.h
@@ -29,8 +29,9 @@
 #include <FCGlobal.h>
 #endif
 
-
-class QAtomicInt;
+#include <assert.h>
+#include <atomic>
+#include <iostream>
 
 namespace Base
 {
@@ -72,6 +73,18 @@ public:
             _toHandle->unref();
     }
 
+    void reset(const Reference<T> &p=Reference<T>()) {
+        *this = p;
+    }
+
+    void swap(Reference<T> &p) {
+        if(*this != p) {
+            auto tmp = p;
+            p = *this;
+            *this = tmp;
+        }
+    }
+
     //**************************************************************************
     // operator implementation
 
@@ -160,20 +173,36 @@ private:
 class BaseExport Handled
 {
 public:
-    Handled();
-    virtual ~Handled();
+    Handled()
+        :_lRefCount(0)
+    {}
 
-    void ref() const;
-    void unref() const;
+    Handled(const Handled&) = delete;
 
-    int getRefCount() const;
-    const Handled& operator = (const Handled&);
+    virtual ~Handled()
+    {
+        if (_lRefCount != 0)
+            std::cerr << "Reference counter of deleted object is not zero!!!!!" << std::endl;
+    }
+
+    void ref() const {++_lRefCount;}
+
+    int unref() const  
+    {
+        int res = --_lRefCount;
+        if (res == 0)
+            delete this;
+        else
+            assert(res>0);
+        return res;
+    }
+
+    int getRefCount(void) const {return _lRefCount;}
+
+    const Handled& operator = (const Handled&) {return *this;}
 
 private:
-    Handled(const Handled&);
-
-private:
-    QAtomicInt* _lRefCount;
+    mutable std::atomic<int> _lRefCount;
 };
 
 } // namespace Base