Revert ref counting implementation and CefObjectTracker (see issue #88)

Author: dmitry-azaraev

CefGlue.Interop.Gen/make_interop.py

@@ -331,7 +331,6 @@ def make_wrapper_g_file(cls):
     body.append('using System.Diagnostics;')
     body.append('using System.Runtime.InteropServices;')
     # body.append('using System.Diagnostics.CodeAnalysis;')
-    body.append('using System.Threading;')
     body.append('using %s;' % schema.interop_namespace)
     body.append('')
 
@@ -425,7 +424,6 @@ def make_proxy_g_body(cls):
     # private fields
     if isImpl:
       result.append(privateOrProtected + ' %s* _self;' % iname)
-      result.append(privateOrProtected + ' int _disposed = 0;')
       result.append('')
 
     # ctor
@@ -434,8 +432,6 @@ def make_proxy_g_body(cls):
         result.append('{')
         result.append(indent + 'if (ptr == null) throw new ArgumentNullException("ptr");')
         result.append(indent + '_self = ptr;')
-        if isRefCountedImpl:
-            result.append(indent + 'CefObjectTracker.Track(this);')
         #
         # todo: diagnostics code: Interlocked.Increment(ref _objCt);
         #
@@ -453,7 +449,7 @@ def make_proxy_g_body(cls):
         # disposable
         result.append('~%s()' % csname)
         result.append('{')
-        result.append(indent + 'if (Interlocked.CompareExchange(ref _disposed, 1, 0) == 0)')
+        result.append(indent + 'if (_self != null)')
         result.append(indent + '{')
         result.append(indent + indent + 'Release();')
         result.append(indent + indent + '_self = null;')
@@ -463,12 +459,11 @@ def make_proxy_g_body(cls):
 
         result.append('public void Dispose()')
         result.append('{')
-        result.append(indent + 'if (Interlocked.CompareExchange(ref _disposed, 1, 0) == 0)')
+        result.append(indent + 'if (_self != null)')
         result.append(indent + '{')
         result.append(indent + indent + 'Release();')
         result.append(indent + indent + '_self = null;')
         result.append(indent + '}')
-        result.append(indent + 'CefObjectTracker.Untrack(this);')
         result.append(indent + 'GC.SuppressFinalize(this);')
         result.append('}')
         result.append('')
@@ -538,6 +533,9 @@ def make_handler_g_body(cls):
     # result.append('private bool _disposed;')
     result.append('')
 
+    result.append('protected object SyncRoot { get { return this; } }')
+    result.append('')
+
     if schema.is_reversible(cls):
         result.append('internal static %s FromNativeOrNull(%s* ptr)' % (csname, iname))
         result.append('{')
@@ -546,8 +544,6 @@ def make_handler_g_body(cls):
         result.append(indent + 'lock (_roots)')
         result.append(indent + '{')
         result.append(indent + indent + 'found = _roots.TryGetValue((IntPtr)ptr, out value);')
-        result.append(indent + indent + '// as we\'re getting the ref from the outside, it\'s our responsibility to decrement it')
-        result.append(indent + indent + 'value.release(ptr);')
         result.append(indent + '}')
         result.append(indent + 'return found ? value : null;')
         result.append('}')
@@ -606,35 +602,43 @@ def make_handler_g_body(cls):
     # todo: verify self pointer in debug
     result.append('private void add_ref(%s* self)' % iname)
     result.append('{')
-    result.append(indent + 'if (Interlocked.Increment(ref _refct) == 1)')
+    result.append(indent + 'lock (SyncRoot)')
     result.append(indent + '{')
-    result.append(indent + indent + 'lock (_roots) { _roots.Add((IntPtr)_self, this); }')
+    result.append(indent + indent + 'var result = ++_refct;')
+    result.append(indent + indent + 'if (result == 1)')
+    result.append(indent + indent + '{')
+    result.append(indent + indent + indent + 'lock (_roots) { _roots.Add((IntPtr)_self, this); }')
+    result.append(indent + indent + '}')
     result.append(indent + '}')
     result.append('}')
     result.append('')
 
     result.append('private int release(%s* self)' % iname)
     result.append('{')
-    result.append(indent + 'if (Interlocked.Decrement(ref _refct) == 0)')
+    result.append(indent + 'lock (SyncRoot)')
     result.append(indent + '{')
-    result.append(indent + indent + 'lock (_roots) { _roots.Remove((IntPtr)_self); }')
+    result.append(indent + indent + 'var result = --_refct;')
+    result.append(indent + indent + 'if (result == 0)')
+    result.append(indent + indent + '{')
+    result.append(indent + indent + indent + 'lock (_roots) { _roots.Remove((IntPtr)_self); }')
     if schema.is_autodispose(cls):
-        result.append(indent + indent + 'Dispose();')
-    result.append(indent + indent + 'return 1;')
+        result.append(indent + indent + indent + 'Dispose();')
+    result.append(indent + indent + indent + 'return 1;')
+    result.append(indent + indent + '}')
+    result.append(indent + indent + 'return 0;')
     result.append(indent + '}')
-    result.append(indent + 'return 0;')
     result.append('}')
     result.append('')
 
     result.append('private int has_one_ref(%s* self)' % iname)
     result.append('{')
-    result.append(indent + 'return _refct == 1 ? 1 : 0;')
+    result.append(indent + 'lock (SyncRoot) { return _refct == 1 ? 1 : 0; }')
     result.append('}')
     result.append('')
 
     result.append('private int has_at_least_one_ref(%s* self)' % iname)
     result.append('{')
-    result.append(indent + 'return _refct != 0 ? 1 : 0;')
+    result.append(indent + 'lock (SyncRoot) { return _refct != 0 ? 1 : 0; }')
     result.append('}')
     result.append('')
 

CefGlue/CefGlue.csproj

@@ -14,7 +14,6 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <Compile Include="CefObjectTracker.cs" />
     <Compile Include="CefRuntime.cs" />
     <Compile Include="CefRuntimePlatform.cs" />
     <Compile Include="Classes.Handlers\CefAccessibilityHandler.cs" />

CefGlue/CefObjectTracker.cs

@@ -13,50 +13,44 @@
     /// </summary>
     public abstract unsafe partial class CefV8Handler
     {
-        private static readonly CefV8Value[] emtpyArgs = new CefV8Value[0];
+        private static readonly CefV8Value[] s_emtpyArgs = new CefV8Value[0];
 
         private int execute(cef_v8handler_t* self, cef_string_t* name, cef_v8value_t* @object, UIntPtr argumentsCount, cef_v8value_t** arguments, cef_v8value_t** retval, cef_string_t* exception)
         {
             CheckSelf(self);
 
-            using (CefObjectTracker.StartTracking())
+            var m_name = cef_string_t.ToString(name);
+            var m_obj = CefV8Value.FromNative(@object);
+            var argc = (int)argumentsCount;
+            CefV8Value[] m_arguments;
+            if (argc == 0) { m_arguments = s_emtpyArgs; }
+            else
             {
-                CheckSelf(self);
-
-                var m_name = cef_string_t.ToString(name);
-                var m_obj = CefV8Value.FromNative(@object);
-                var argc = (int)argumentsCount;
-                CefV8Value[] m_arguments;
-                if (argc == 0) { m_arguments = emtpyArgs; }
-                else
+                m_arguments = new CefV8Value[argc];
+                for (var i = 0; i < argc; i++)
                 {
-                    m_arguments = new CefV8Value[argc];
-                    for (var i = 0; i < argc; i++)
-                    {
-                        m_arguments[i] = CefV8Value.FromNative(arguments[i]);
-                    }
+                    m_arguments[i] = CefV8Value.FromNative(arguments[i]);
                 }
+            }
 
+            CefV8Value m_returnValue;
+            string m_exception;
 
-                CefV8Value m_returnValue;
-                string m_exception;
-
-                var handled = Execute(m_name, m_obj, m_arguments, out m_returnValue, out m_exception);
+            var handled = Execute(m_name, m_obj, m_arguments, out m_returnValue, out m_exception);
 
-                if (handled)
+            if (handled)
+            {
+                if (m_exception != null)
                 {
-                    if (m_exception != null)
-                    {
-                        cef_string_t.Copy(m_exception, exception);
-                    }
-                    else if (m_returnValue != null)
-                    {
-                        *retval = m_returnValue.ToNative();
-                    }
+                    cef_string_t.Copy(m_exception, exception);
+                }
+                else if (m_returnValue != null)
+                {
+                    *retval = m_returnValue.ToNative();
                 }
-
-                return handled ? 1 : 0;
             }
+
+            return handled ? 1 : 0;
         }
 
         /// <summary>