Bug 1138620 - Part 1: Allow binary modules to create unmonitored threads that doesn't keep the Nuwa process from stabalization. r=nfroyd

xpcom/glue/nsThreadUtils.cpp

@@ -93,6 +93,67 @@ NS_NewThread(nsIThread** aResult, nsIRunnable* aEvent, uint32_t aStackSize)
   return NS_OK;
 }
 
+#if defined(MOZ_NUWA_PROCESS) && !defined(XPCOM_GLUE_AVOID_NSPR)
+
+namespace {
+class IgnoreThreadStatusRunnable : public nsIRunnable
+{
+public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIRUNNABLE
+
+private:
+  virtual ~IgnoreThreadStatusRunnable() = default;
+};
+
+NS_IMPL_ISUPPORTS(IgnoreThreadStatusRunnable, nsIRunnable)
+
+NS_IMETHODIMP IgnoreThreadStatusRunnable::Run(void)
+{
+#ifdef MOZILLA_INTERNAL_API
+  nsThreadManager::get()->SetIgnoreThreadStatus();
+  return NS_OK;
+#endif
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+} // Anonymous namespace.
+#endif // defined(MOZ_NUWA_PROCESS) && !defined(XPCOM_GLUE_AVOID_NSPR)
+
+NS_METHOD
+NS_NewUnmonitoredThread(nsIThread** aResult,
+                        nsIRunnable* aEvent,
+                        uint32_t aStackSize)
+{
+#if defined(MOZ_NUWA_PROCESS) && !defined(XPCOM_GLUE_AVOID_NSPR)
+  // Hold a ref while dispatching the initial event to match NS_NewThread()
+  nsCOMPtr<nsIThread> thread;
+  nsresult rv = NS_NewThread(getter_AddRefs(thread), nullptr, aStackSize);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  nsCOMPtr<nsIRunnable> ignoreme = new IgnoreThreadStatusRunnable();
+  rv = thread->Dispatch(ignoreme, NS_DISPATCH_NORMAL);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (aEvent) {
+    rv = thread->Dispatch(aEvent, NS_DISPATCH_NORMAL);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+  }
+
+  *aResult = nullptr;
+  thread.swap(*aResult);
+  return rv;
+#else
+  return NS_NewThread(aResult, aEvent, aStackSize);
+#endif
+}
+
 NS_METHOD
 NS_GetCurrentThread(nsIThread** aResult)
 {

xpcom/glue/nsThreadUtils.h

@@ -61,6 +61,17 @@ NS_NewThread(nsIThread** aResult,
              nsIRunnable* aInitialEvent = nullptr,
              uint32_t aStackSize = nsIThreadManager::DEFAULT_STACK_SIZE);
 
+/**
+ * Create a new thread that is ignored in thread status monitoring by default on
+ * platforms with Nuwa process enabled. On non-Nuwa platforms, this function is
+ * identical to NS_NewThread().
+ */
+extern NS_METHOD
+NS_NewUnmonitoredThread(nsIThread** aResult,
+                        nsIRunnable* aInitialEvent = nullptr,
+                        uint32_t aStackSize =
+                                 nsIThreadManager::DEFAULT_STACK_SIZE);
+
 /**
  * Creates a named thread, otherwise the same as NS_NewThread
  */