Bug 610381 part B - Report thread-usage errors to the error console directly from xpconnect, so that the error console shows them even when extension authors are using asynchronous dispatch. r=jst a=blocking2.0

--HG--
extra : rebase_source : 973d58b5d9be243f92e261ca0a2664bdbf120546

js/src/xpconnect/src/xpcwrappedjs.cpp

@@ -44,6 +44,7 @@
 #include "xpcprivate.h"
 #include "nsAtomicRefcnt.h"
 #include "nsThreadUtils.h"
+#include "nsTextFormatter.h"
 
 // NOTE: much of the fancy footwork is done in xpcstubs.cpp
 
@@ -572,6 +573,17 @@ nsXPCWrappedJS::CallMethod(PRUint16 methodIndex,
     if(!IsValid())
         return NS_ERROR_UNEXPECTED;
     if (NS_IsMainThread() != mMainThread) {
+        NS_NAMED_LITERAL_STRING(kFmt, "Attempt to use JS function on a different thread calling %s.%s. JS objects may not be shared across threads.");
+        PRUnichar* msg =
+            nsTextFormatter::smprintf(kFmt.get(),
+                                      GetClass()->GetInterfaceName(),
+                                      info->name);
+        nsCOMPtr<nsIConsoleService> cs =
+            do_GetService(NS_CONSOLESERVICE_CONTRACTID);
+        if (cs)
+            cs->LogStringMessage(msg);
+        NS_Free(msg);
+        
         return NS_ERROR_NOT_SAME_THREAD;
     }
     return GetClass()->CallMethod(this, methodIndex, info, params);

js/src/xpconnect/tests/unit/test_bug608142.js

@@ -40,6 +40,19 @@ function run_test() {
     var tm = Components.classes["@mozilla.org/thread-manager;1"].getService();
     var thr = tm.newThread(0);
 
+    var foundThreadError = false;
+ 
+    var listener = {
+        observe: function(message) {
+            if (/JS function on a different thread/.test(message.message))
+                foundThreadError = true;
+        }
+    };
+
+    var cs = Components.classes["@mozilla.org/consoleservice;1"].
+        getService(Components.interfaces.nsIConsoleService);
+    cs.registerListener(listener);
+
     thr.dispatch({
         run: function() {
             do_check_true(false);
@@ -47,5 +60,8 @@ function run_test() {
     }, Components.interfaces.nsIThread.DISPATCH_NORMAL);
 
     thr.shutdown();
+
+    cs.unregisterListener(listener);
+    do_check_true(foundThreadError);
 }