Changeset 102857 in webkit

Timestamp:

Dec 14, 2011 5:37:50 PM (12 years ago)

Author:

andersca@apple.com

Message:

binding a member function should ref/deref the object pointer if needed
​https://bugs.webkit.org/show_bug.cgi?id=74552

Reviewed by Sam Weinig.

Source/JavaScriptCore:

Add a HasRefAndDeref helper class template which checks if a given class type has ref and deref
member functions which the right type. Use this to determine if we should ref/deref the first parameter.

• wtf/Functional.h:

(WTF::R):
(WTF::C::):
(WTF::RefAndDeref::ref):
(WTF::RefAndDeref::deref):

Tools:

Add new tests.

• TestWebKitAPI/Tests/WTF/Functional.cpp:

(TestWebKitAPI::B::B):
(TestWebKitAPI::B::~B):
(TestWebKitAPI::B::ref):
(TestWebKitAPI::B::deref):
(TestWebKitAPI::B::f):
(TestWebKitAPI::B::g):
(TestWebKitAPI::TEST):

Location:

trunk

Files:

• Source/JavaScriptCore/ChangeLog (modified) (1 diff)
• Source/JavaScriptCore/wtf/Functional.h (modified) (9 diffs)
• Tools/ChangeLog (modified) (1 diff)
• Tools/TestWebKitAPI/Tests/WTF/Functional.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2011-12-14  Anders Carlsson  <andersca@apple.com>
+
+        binding a member function should ref/deref the object pointer if needed
+        https://bugs.webkit.org/show_bug.cgi?id=74552
+
+        Reviewed by Sam Weinig.
+
+        Add a HasRefAndDeref helper class template which checks if a given class type has ref and deref
+        member functions which the right type. Use this to determine if we should ref/deref the first parameter.
+
+        * wtf/Functional.h:
+        (WTF::R):
+        (WTF::C::):
+        (WTF::RefAndDeref::ref):
+        (WTF::RefAndDeref::deref):
+
 2011-12-14  Hajime Morrita  <morrita@chromium.org>
 

trunk/Source/JavaScriptCore/wtf/Functional.h

@@ -39 +39 @@
 // package up and invoke function calls inside WebCore.
 
+// Helper class template to determine whether a given type has ref and deref member functions
+// with the right type signature.
+template<typename T> class HasRefAndDeref {
+    typedef char YesType;
+    struct NoType {
+        char padding[8];
+    };
+
+    template<typename U, U, U> struct TypeChecker { };
+
+    template<typename U>
+    static YesType refAndDerefCheck(TypeChecker<void (U::*)(), &U::ref, &U::deref>*);
+
+    template<typename U>
+    static NoType refAndDerefCheck(...);
+
+public:
+    static const bool value = sizeof(refAndDerefCheck<T>(0)) == sizeof(YesType);
+};
+
 // A FunctionWrapper is a class template that can wrap a function pointer or a member function pointer and
 // provide a unified interface for calling that function.
@@ -46 +66 @@
 public:
     typedef R ResultType;
+    static const bool shouldRefFirstParameter = false;
 
     explicit FunctionWrapper(R (*function)())
@@ -64 +85 @@
 public:
     typedef R ResultType;
+    static const bool shouldRefFirstParameter = false;
 
     explicit FunctionWrapper(R (*function)(P0))
@@ -82 +104 @@
 public:
     typedef R ResultType;
+    static const bool shouldRefFirstParameter = false;
 
     explicit FunctionWrapper(R (*function)(P0, P1))
@@ -100 +123 @@
 public:
     typedef R ResultType;
+    static const bool shouldRefFirstParameter = HasRefAndDeref<C>::value;
 
     explicit FunctionWrapper(R (C::*function)())
@@ -118 +142 @@
 public:
     typedef R ResultType;
+    static const bool shouldRefFirstParameter = HasRefAndDeref<C>::value;
 
     explicit FunctionWrapper(R (C::*function)(P0))
@@ -131 +156 @@
 private:
     R (C::*m_function)(P0);
+};
+
+template<typename T, bool shouldRefAndDeref> struct RefAndDeref {
+    static void ref(T) { }
+    static void deref(T) { }
+};
+
+template<typename T> struct RefAndDeref<T*, true> {
+    static void ref(T* t) { t->ref(); }
+    static void deref(T* t) { t->deref(); }
 };
 
@@ -173 +208 @@
         , m_p0(p0)
     {
+        RefAndDeref<P0, FunctionWrapper::shouldRefFirstParameter>::ref(m_p0);
+    }
+
+    ~BoundFunctionImpl()
+    {
+        RefAndDeref<P0, FunctionWrapper::shouldRefFirstParameter>::deref(m_p0);
     }
 
@@ -192 +233 @@
         , m_p1(p1)
     {
+        RefAndDeref<P0, FunctionWrapper::shouldRefFirstParameter>::ref(m_p0);
+    }
+    
+    ~BoundFunctionImpl()
+    {
+        RefAndDeref<P0, FunctionWrapper::shouldRefFirstParameter>::deref(m_p0);
     }
 

trunk/Tools/ChangeLog

@@ +1 @@
+2011-12-14  Anders Carlsson  <andersca@apple.com>
+
+        binding a member function should ref/deref the object pointer if needed
+        https://bugs.webkit.org/show_bug.cgi?id=74552
+
+        Reviewed by Sam Weinig.
+
+        Add new tests.
+
+        * TestWebKitAPI/Tests/WTF/Functional.cpp:
+        (TestWebKitAPI::B::B):
+        (TestWebKitAPI::B::~B):
+        (TestWebKitAPI::B::ref):
+        (TestWebKitAPI::B::deref):
+        (TestWebKitAPI::B::f):
+        (TestWebKitAPI::B::g):
+        (TestWebKitAPI::TEST):
+
 2011-12-14  Hajime Morrita  <morrita@chromium.org>
 

trunk/Tools/TestWebKitAPI/Tests/WTF/Functional.cpp

@@ -106 +106 @@
 }
 
+class B {
+public:
+    B()
+        : m_numRefCalls(0)
+        , m_numDerefCalls(0)
+    {
+    }
+
+    ~B()
+    {
+        ASSERT_TRUE(m_numRefCalls == m_numDerefCalls);
+        ASSERT_GT(m_numRefCalls, 0);
+    }
+
+    void ref()
+    {
+        m_numRefCalls++;
+    }
+
+    void deref()
+    {
+        m_numDerefCalls++;
+    }
+
+    void f() { ASSERT_GT(m_numRefCalls, 0); }
+    void g(int) { ASSERT_GT(m_numRefCalls, 0); }
+
+private:
+    int m_numRefCalls;
+    int m_numDerefCalls;
+};
+
+TEST(FunctionalTest, MemberFunctionBindRefDeref)
+{
+    B b;
+
+    Function<void ()> function1 = bind(&B::f, &b);
+    function1();
+
+    Function<void ()> function2 = bind(&B::g, &b, 10);
+    function2();
+}
+
 } // namespace TestWebKitAPI