fixes bug 210125 "need to be able to AsyncWait for closure only" r=dougt sr=bzbarsky

git-svn-id: svn://10.0.0.236/trunk@147597 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/xpcom/proxy/src/nsProxyRelease.cpp

@@ -0,0 +1,55 @@
+#include "nsProxyRelease.h"
+
+PR_STATIC_CALLBACK(void*)
+HandleProxyReleaseEvent(PLEvent *self)
+{              
+    nsISupports* owner = (nsISupports*) self->owner;
+    NS_RELEASE(owner);                                                                                              
+    return nsnull;                                            
+}
+
+PR_STATIC_CALLBACK(void)
+DestroyProxyReleaseEvent(PLEvent *self)
+{
+    delete self;
+}
+
+NS_COM nsresult
+NS_ProxyRelease(nsIEventTarget *target, nsISupports *doomed, PRBool alwaysProxy)
+{
+    nsresult rv;
+
+    if (!target) {
+        NS_RELEASE(doomed);
+        return NS_OK;
+    }
+
+    if (!alwaysProxy) {
+        PRBool onCurrentThread = PR_FALSE;
+        rv = target->IsOnCurrentThread(&onCurrentThread);
+        if (NS_SUCCEEDED(rv) && onCurrentThread) {
+            NS_RELEASE(doomed);
+            return NS_OK;
+        }
+    }
+
+    PLEvent *ev = new PLEvent;
+    if (!ev) {
+        // we do not release doomed here since it may cause a delete on the
+        // wrong thread.  better to leak than crash. 
+        return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    PL_InitEvent(ev, doomed,
+                 HandleProxyReleaseEvent,
+                 DestroyProxyReleaseEvent);
+
+    rv = target->PostEvent(ev);
+    if (NS_FAILED(rv)) {
+        NS_WARNING("failed to post proxy release event");
+        PL_DestroyEvent(ev);
+        // again, it is better to leak the doomed object than risk crashing as
+        // a result of deleting it on the wrong thread.
+    }
+    return rv;
+}