1 files changed, 62 insertions, 0 deletions
diff --git a/netwerk/base/AutoClose.h b/netwerk/base/AutoClose.h
new file mode 100644
index 0000000000..a0e3a48e17
--- /dev/null
+++ b/netwerk/base/AutoClose.h
@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_net_AutoClose_h
+#define mozilla_net_AutoClose_h
+
+#include "nsCOMPtr.h"
+#include "mozilla/Mutex.h"
+
+namespace mozilla {
+namespace net {
+
+// A container for XPCOM streams (e.g. nsIAsyncInputStream) and other
+// refcounted classes that need to have the Close() method called explicitly
+// before they are destroyed.
+template <typename T>
+class AutoClose {
+ public:
+  AutoClose() : mMutex("net::AutoClose.mMutex") {}
+  ~AutoClose() { CloseAndRelease(); }
+
+  explicit operator bool() {
+    MutexAutoLock lock(mMutex);
+    return mPtr;
+  }
+
+  already_AddRefed<T> forget() {
+    MutexAutoLock lock(mMutex);
+    return mPtr.forget();
+  }
+
+  void takeOver(nsCOMPtr<T>& rhs) { TakeOverInternal(rhs.forget()); }
+
+  void CloseAndRelease() { TakeOverInternal(nullptr); }
+
+ private:
+  void TakeOverInternal(already_AddRefed<T>&& aOther) {
+    nsCOMPtr<T> ptr(std::move(aOther));
+    {
+      MutexAutoLock lock(mMutex);
+      ptr.swap(mPtr);
+    }
+
+    if (ptr) {
+      ptr->Close();
+    }
+  }
+
+  void operator=(const AutoClose<T>&) = delete;
+  AutoClose(const AutoClose<T>&) = delete;
+
+  nsCOMPtr<T> mPtr;
+  Mutex mMutex MOZ_UNANNOTATED;
+};
+
+}  // namespace net
+}  // namespace mozilla
+
+#endif  // mozilla_net_AutoClose_h