Changeset 41536 in webkit for trunk/JavaScriptCore/wtf/Threading.h

Timestamp:

Mar 9, 2009, 2:01:42 PM (16 years ago)

Author:

[email protected]

Message:

2009-03-09 David Levin <​[email protected]>

Reviewed by Darin Adler.

Bug 23175: String and UString should be able to share a UChar* buffer.
<​https://bugs.webkit.org/show_bug.cgi?id=23175>

Add CrossThreadRefCounted.

• wtf/CrossThreadRefCounted.h: Added. (WTF::CrossThreadRefCounted::create): (WTF::CrossThreadRefCounted::isShared): (WTF::CrossThreadRefCounted::dataAccessMustBeThreadSafe): (WTF::CrossThreadRefCounted::mayBePassedToAnotherThread): (WTF::CrossThreadRefCounted::CrossThreadRefCounted): (WTF::CrossThreadRefCounted::~CrossThreadRefCounted): (WTF::CrossThreadRefCounted::ref): (WTF::CrossThreadRefCounted::deref): (WTF::CrossThreadRefCounted::release): (WTF::CrossThreadRefCounted::copy): (WTF::CrossThreadRefCounted::threadSafeDeref):
• wtf/RefCounted.h:
• wtf/Threading.h: (WTF::ThreadSafeSharedBase::ThreadSafeSharedBase): (WTF::ThreadSafeSharedBase::derefBase): (WTF::ThreadSafeShared::ThreadSafeShared): (WTF::ThreadSafeShared::deref):

File:

• trunk/JavaScriptCore/wtf/Threading.h (modified) (2 diffs)

trunk/JavaScriptCore/wtf/Threading.h

@@ -206 +206 @@
 #endif
 
-template<class T> class ThreadSafeShared : Noncopyable {
-public:
-    ThreadSafeShared(int initialRefCount = 1)
+class ThreadSafeSharedBase : Noncopyable {
+public:
+    ThreadSafeSharedBase(int initialRefCount = 1)
         : m_refCount(initialRefCount)
     {
@@ -223 +223 @@
     }
 
-    void deref()
+    bool hasOneRef()
+    {
+        return refCount() == 1;
+    }
+
+    int refCount() const
+    {
+#if !USE(LOCKFREE_THREADSAFESHARED)
+        MutexLocker locker(m_mutex);
+#endif
+        return static_cast<int const volatile &>(m_refCount);
+    }
+
+protected:
+    // Returns whether the pointer should be freed or not.
+    bool derefBase()
     {
 #if USE(LOCKFREE_THREADSAFESHARED)
         if (atomicDecrement(&m_refCount) <= 0)
-#else
+            return true;
+#else
+        int refCount;
         {
             MutexLocker locker(m_mutex);
             --m_refCount;
+            refCount = m_refCount;
         }
-        if (m_refCount <= 0)
-#endif
-            delete static_cast<T*>(this);
-    }
-
-    bool hasOneRef()
-    {
-        return refCount() == 1;
-    }
-
-    int refCount() const
-    {
-#if !USE(LOCKFREE_THREADSAFESHARED)
-        MutexLocker locker(m_mutex);
-#endif
-        return static_cast<int const volatile &>(m_refCount);
+        if (refCount <= 0)
+            return true;
+#endif
+        return false;
     }
 
 private:
+    template<class T>
+    friend class CrossThreadRefCounted;
+
     int m_refCount;
 #if !USE(LOCKFREE_THREADSAFESHARED)
     mutable Mutex m_mutex;
 #endif
+};
+
+template<class T> class ThreadSafeShared : public ThreadSafeSharedBase {
+public:
+    ThreadSafeShared(int initialRefCount = 1)
+        : ThreadSafeSharedBase(initialRefCount)
+    {
+    }
+
+    void deref()
+    {
+        if (derefBase())
+            delete static_cast<T*>(this);
+    }
 };