Bug 901291 - Get WebIDL callbacks working on Workers. r=khuey

content/base/public/nsContentUtils.h

@@ -1534,6 +1534,7 @@ public:
 
   static JSContext *GetCurrentJSContext();
   static JSContext *GetSafeJSContext();
+  static JSContext *GetDefaultJSContextForThread();
 
   /**
    * Case insensitive comparison between two strings. However it only ignores

content/base/src/nsContentUtils.cpp

@@ -1766,6 +1766,7 @@ namespace mozilla {
 namespace dom {
 namespace workers {
 extern bool IsCurrentThreadRunningChromeWorker();
+extern JSContext* GetCurrentThreadJSContext();
 }
 }
 }
@@ -5197,6 +5198,17 @@ nsContentUtils::GetSafeJSContext()
   return sXPConnect->GetSafeJSContext();
 }
 
+/* static */
+JSContext *
+nsContentUtils::GetDefaultJSContextForThread()
+{
+  if (MOZ_LIKELY(NS_IsMainThread())) {
+    return GetSafeJSContext();
+  } else {
+    return workers::GetCurrentThreadJSContext();
+  }
+}
+
 /* static */
 nsresult
 nsContentUtils::ASCIIToLower(nsAString& aStr)

dom/bindings/BindingUtils.cpp

@@ -673,6 +673,28 @@ NativeInterface2JSObjectAndThrowIfFailed(JSContext* aCx,
                                          bool aAllowNativeWrapper)
 {
   nsresult rv;
+  // Inline some logic from XPCConvert::NativeInterfaceToJSObject that we need
+  // on all threads.
+  nsWrapperCache *cache = aHelper.GetWrapperCache();
+
+  if (cache && cache->IsDOMBinding()) {
+      JS::RootedObject obj(aCx, cache->GetWrapper());
+      if (!obj) {
+          obj = cache->WrapObject(aCx, aScope);
+      }
+
+      if (obj && aAllowNativeWrapper && !JS_WrapObject(aCx, obj.address())) {
+        return false;
+      }
+
+      if (obj) {
+        *aRetval = JS::ObjectValue(*obj);
+        return true;
+      }
+  }
+
+  MOZ_ASSERT(NS_IsMainThread());
+
   if (!XPCConvert::NativeInterface2JSObject(aRetval, NULL, aHelper, aIID,
                                             NULL, aAllowNativeWrapper, &rv)) {
     // I can't tell if NativeInterface2JSObject throws JS exceptions

dom/bindings/CallbackObject.cpp

@@ -17,6 +17,7 @@
 #include "nsCxPusher.h"
 #include "nsIScriptSecurityManager.h"
 #include "xpcprivate.h"
+#include "WorkerPrivate.h"
 
 namespace mozilla {
 namespace dom {
@@ -49,7 +50,11 @@ CallbackObject::CallSetup::CallSetup(JS::Handle<JSObject*> aCallback,
   , mCompartment(aCompartment)
   , mErrorResult(aRv)
   , mExceptionHandling(aExceptionHandling)
+  , mIsMainThread(NS_IsMainThread())
 {
+  if (mIsMainThread) {
+    nsContentUtils::EnterMicroTask();
+  }
   // We need to produce a useful JSContext here.  Ideally one that the callback
   // is in some sense associated with, so that we can sort of treat it as a
   // "script entry point".  Though once we actually have script entry points,
@@ -58,46 +63,50 @@ CallbackObject::CallSetup::CallSetup(JS::Handle<JSObject*> aCallback,
 
   // First, find the real underlying callback.
   JSObject* realCallback = js::UncheckedUnwrap(aCallback);
-
-  // Now get the nsIScriptGlobalObject for this callback.
   JSContext* cx = nullptr;
-  nsIScriptContext* ctx = nullptr;
-  nsIScriptGlobalObject* sgo = nsJSUtils::GetStaticScriptGlobal(realCallback);
-  if (sgo) {
-    // Make sure that if this is a window it's the current inner, since the
-    // nsIScriptContext and hence JSContext are associated with the outer
-    // window.  Which means that if someone holds on to a function from a
-    // now-unloaded document we'd have the new document as the script entry
-    // point...
-    nsCOMPtr<nsPIDOMWindow> win = do_QueryInterface(sgo);
-    if (win) {
-      MOZ_ASSERT(win->IsInnerWindow());
-      nsPIDOMWindow* outer = win->GetOuterWindow();
-      if (!outer || win != outer->GetCurrentInnerWindow()) {
-        // Just bail out from here
-        return;
+
+  if (mIsMainThread) {
+    // Now get the nsIScriptGlobalObject for this callback.
+    nsIScriptContext* ctx = nullptr;
+    nsIScriptGlobalObject* sgo = nsJSUtils::GetStaticScriptGlobal(realCallback);
+    if (sgo) {
+      // Make sure that if this is a window it's the current inner, since the
+      // nsIScriptContext and hence JSContext are associated with the outer
+      // window.  Which means that if someone holds on to a function from a
+      // now-unloaded document we'd have the new document as the script entry
+      // point...
+      nsCOMPtr<nsPIDOMWindow> win = do_QueryInterface(sgo);
+      if (win) {
+        MOZ_ASSERT(win->IsInnerWindow());
+        nsPIDOMWindow* outer = win->GetOuterWindow();
+        if (!outer || win != outer->GetCurrentInnerWindow()) {
+          // Just bail out from here
+          return;
+        }
+      }
+      // if not a window at all, just press on
+
+      ctx = sgo->GetContext();
+      if (ctx) {
+        // We don't check whether scripts are enabled on ctx, because
+        // CheckFunctionAccess will do that anyway... and because we ignore them
+        // being disabled if the callee is system.
+        cx = ctx->GetNativeContext();
       }
     }
-    // if not a window at all, just press on
 
-    ctx = sgo->GetContext();
-    if (ctx) {
-      // We don't check whether scripts are enabled on ctx, because
-      // CheckFunctionAccess will do that anyway... and because we ignore them
-      // being disabled if the callee is system.
-      cx = ctx->GetNativeContext();
+    if (!cx) {
+      // We didn't manage to hunt down a script global to work with.  Just fall
+      // back on using the safe context.
+      cx = nsContentUtils::GetSafeJSContext();
     }
-  }
 
-  if (!cx) {
-    // We didn't manage to hunt down a script global to work with.  Just fall
-    // back on using the safe context.
-    cx = nsContentUtils::GetSafeJSContext();
+    // Make sure our JSContext is pushed on the stack.
+    mCxPusher.Push(cx);
+  } else {
+    cx = workers::GetCurrentThreadJSContext();
   }
 
-  // Make sure our JSContext is pushed on the stack.
-  mCxPusher.Push(cx);
-
   // Unmark the callable, and stick it in a Rooted before it can go gray again.
   // Nothing before us in this function can trigger a CC, so it's safe to wait
   // until here it do the unmark. This allows us to order the following two
@@ -109,16 +118,18 @@ CallbackObject::CallSetup::CallSetup(JS::Handle<JSObject*> aCallback,
   JS::ExposeObjectToActiveJS(aCallback);
   mRootedCallable.construct(cx, aCallback);
 
-  // Check that it's ok to run this callback at all.
-  // FIXME: Bug 807371: we want a less silly check here.
-  // Make sure to unwrap aCallback before passing it in, because
-  // getting principals from wrappers is silly.
-  nsresult rv = nsContentUtils::GetSecurityManager()->
-    CheckFunctionAccess(cx, js::UncheckedUnwrap(aCallback), nullptr);
+  if (mIsMainThread) {
+    // Check that it's ok to run this callback at all.
+    // FIXME: Bug 807371: we want a less silly check here.
+    // Make sure to unwrap aCallback before passing it in, because
+    // getting principals from wrappers is silly.
+    nsresult rv = nsContentUtils::GetSecurityManager()->
+      CheckFunctionAccess(cx, js::UncheckedUnwrap(aCallback), nullptr);
 
-  if (NS_FAILED(rv)) {
-    // Security check failed.  We're done here.
-    return;
+    if (NS_FAILED(rv)) {
+      // Security check failed.  We're done here.
+      return;
+    }
   }
 
   // Enter the compartment of our callback, so we can actually work with it.
@@ -204,12 +215,19 @@ CallbackObject::CallSetup::~CallSetup()
 
   // Popping an nsCxPusher is safe even if it never got pushed.
   mCxPusher.Pop();
+
+  // It is important that this is the last thing we do, after leaving the
+  // compartment and popping the context.
+  if (mIsMainThread) {
+    nsContentUtils::LeaveMicroTask();
+  }
 }
 
 already_AddRefed<nsISupports>
 CallbackObjectHolderBase::ToXPCOMCallback(CallbackObject* aCallback,
                                           const nsIID& aIID) const
 {
+  MOZ_ASSERT(NS_IsMainThread());
   if (!aCallback) {
     return nullptr;
   }

dom/bindings/CallbackObject.h

@@ -151,10 +151,6 @@ protected:
 
     // And now members whose construction/destruction order we need to control.
 
-    // Put our nsAutoMicrotask first, so it gets destroyed after everything else
-    // is gone
-    nsAutoMicroTask mMt;
-
     nsCxPusher mCxPusher;
 
     // Constructed the rooter within the scope of mCxPusher above, so that it's
@@ -172,6 +168,7 @@ protected:
     ErrorResult& mErrorResult;
     const ExceptionHandling mExceptionHandling;
     uint32_t mSavedJSContextOptions;
+    const bool mIsMainThread;
   };
 };
 

js/xpconnect/src/XPCConvert.cpp

@@ -827,7 +827,7 @@ XPCConvert::NativeInterface2JSObject(jsval* d,
         return false;
 
     // First, see if this object supports the wrapper cache.
-    // Note: If |cache->IsProxy()| is true, then it means that the object
+    // Note: If |cache->IsDOMBinding()| is true, then it means that the object
     // implementing it doesn't want a wrapped native as its JS Object, but
     // instead it provides its own proxy object. In that case, the object
     // to use is found as cache->GetWrapper(). If that is null, then the
@@ -862,7 +862,7 @@ XPCConvert::NativeInterface2JSObject(jsval* d,
     if (cpow) {
         if (!JS_WrapObject(cx, cpow.address()))
             return false;
-        *d = OBJECT_TO_JSVAL(cpow);
+        *d = JS::ObjectValue(*cpow);
         return true;
     }