1 files changed, 63 insertions, 0 deletions
diff --git a/xpcom/base/ClearOnShutdown.cpp b/xpcom/base/ClearOnShutdown.cpp
new file mode 100644
index 0000000000..700785736d
--- /dev/null
+++ b/xpcom/base/ClearOnShutdown.cpp
@@ -0,0 +1,63 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=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/. */
+
+#include "mozilla/ClearOnShutdown.h"
+
+namespace mozilla {
+namespace ClearOnShutdown_Internal {
+
+Array<StaticAutoPtr<ShutdownList>,
+      static_cast<size_t>(ShutdownPhase::ShutdownPhase_Length)>
+    sShutdownObservers;
+ShutdownPhase sCurrentClearOnShutdownPhase = ShutdownPhase::NotInShutdown;
+
+void InsertIntoShutdownList(ShutdownObserver* aObserver, ShutdownPhase aPhase) {
+  // Adding a ClearOnShutdown for a "past" phase is an error.
+  if (PastShutdownPhase(aPhase)) {
+    MOZ_ASSERT(false, "ClearOnShutdown for phase that already was cleared");
+    aObserver->Shutdown();
+    delete aObserver;
+    return;
+  }
+
+  if (!(sShutdownObservers[static_cast<size_t>(aPhase)])) {
+    sShutdownObservers[static_cast<size_t>(aPhase)] = new ShutdownList();
+  }
+  sShutdownObservers[static_cast<size_t>(aPhase)]->insertBack(aObserver);
+}
+
+}  // namespace ClearOnShutdown_Internal
+
+// Called by AdvanceShutdownPhase each time we switch a phase. Will null out
+// pointers added by ClearOnShutdown for all phases up to and including aPhase.
+void KillClearOnShutdown(ShutdownPhase aPhase) {
+  using namespace ClearOnShutdown_Internal;
+
+  MOZ_ASSERT(NS_IsMainThread());
+  // Shutdown only goes one direction...
+  MOZ_ASSERT(!PastShutdownPhase(aPhase));
+
+  // Set the phase before notifying observers to make sure that they can't run
+  // any code which isn't allowed to run after the start of this phase.
+  sCurrentClearOnShutdownPhase = aPhase;
+
+  // It's impossible to add an entry for a "past" phase; this is blocked in
+  // ClearOnShutdown, but clear them out anyways in case there are phases
+  // that weren't passed to KillClearOnShutdown.
+  for (size_t phase = static_cast<size_t>(ShutdownPhase::First);
+       phase <= static_cast<size_t>(aPhase); phase++) {
+    if (sShutdownObservers[static_cast<size_t>(phase)]) {
+      while (ShutdownObserver* observer =
+                 sShutdownObservers[static_cast<size_t>(phase)]->popLast()) {
+        observer->Shutdown();
+        delete observer;
+      }
+      sShutdownObservers[static_cast<size_t>(phase)] = nullptr;
+    }
+  }
+}
+
+}  // namespace mozilla