1 files changed, 167 insertions, 0 deletions
diff --git a/dom/fs/child/FileSystemShutdownBlocker.cpp b/dom/fs/child/FileSystemShutdownBlocker.cpp
new file mode 100644
index 0000000000..bddbf18c6b
--- /dev/null
+++ b/dom/fs/child/FileSystemShutdownBlocker.cpp
@@ -0,0 +1,167 @@
+/* -*- 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 "fs/FileSystemShutdownBlocker.h"
+
+#include "MainThreadUtils.h"
+#include "mozilla/Services.h"
+#include "mozilla/dom/quota/QuotaCommon.h"
+#include "mozilla/dom/quota/ResultExtensions.h"
+#include "nsComponentManagerUtils.h"
+#include "nsIAsyncShutdown.h"
+#include "nsISupportsImpl.h"
+#include "nsIWritablePropertyBag2.h"
+#include "nsStringFwd.h"
+
+namespace mozilla::dom::fs {
+
+namespace {
+
+nsString CreateBlockerName() {
+  const int32_t blockerIdLength = 32;
+  nsAutoCString blockerId;
+  blockerId.SetLength(blockerIdLength);
+  NS_MakeRandomString(blockerId.BeginWriting(), blockerIdLength);
+
+  nsString blockerName = u"OPFS_"_ns;
+  blockerName.Append(NS_ConvertUTF8toUTF16(blockerId));
+
+  return blockerName;
+}
+
+class FileSystemWritableBlocker : public FileSystemShutdownBlocker {
+ public:
+  FileSystemWritableBlocker() : mName(CreateBlockerName()) {}
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIASYNCSHUTDOWNBLOCKER
+
+  NS_IMETHODIMP Block() override;
+
+  NS_IMETHODIMP Unblock() override;
+
+ protected:
+  virtual ~FileSystemWritableBlocker() = default;
+
+  Result<already_AddRefed<nsIAsyncShutdownClient>, nsresult> GetBarrier() const;
+
+ private:
+  const nsString mName;
+};
+
+NS_IMPL_ISUPPORTS_INHERITED(FileSystemWritableBlocker,
+                            FileSystemShutdownBlocker, nsIAsyncShutdownBlocker)
+
+NS_IMETHODIMP FileSystemWritableBlocker::Block() {
+  MOZ_ASSERT(NS_IsMainThread());
+  QM_TRY_UNWRAP(nsCOMPtr<nsIAsyncShutdownClient> barrier, GetBarrier());
+
+  QM_TRY(MOZ_TO_RESULT(barrier->AddBlocker(
+      this, NS_ConvertUTF8toUTF16(nsCString(__FILE__)), __LINE__,
+      NS_ConvertUTF8toUTF16(nsCString(__func__)))));
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP FileSystemWritableBlocker::Unblock() {
+  MOZ_ASSERT(NS_IsMainThread());
+  QM_TRY_UNWRAP(nsCOMPtr<nsIAsyncShutdownClient> barrier, GetBarrier());
+
+  MOZ_ASSERT(NS_SUCCEEDED(barrier->RemoveBlocker(this)));
+
+  return NS_OK;
+}
+
+Result<already_AddRefed<nsIAsyncShutdownClient>, nsresult>
+FileSystemWritableBlocker::GetBarrier() const {
+  nsCOMPtr<nsIAsyncShutdownService> svc = services::GetAsyncShutdownService();
+  QM_TRY(OkIf(svc), Err(NS_ERROR_FAILURE));
+
+  nsCOMPtr<nsIAsyncShutdownClient> barrier;
+  QM_TRY(MOZ_TO_RESULT(svc->GetXpcomWillShutdown(getter_AddRefs(barrier))));
+
+  return barrier.forget();
+}
+
+NS_IMETHODIMP
+FileSystemWritableBlocker::GetName(nsAString& aName) {
+  aName = mName;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FileSystemWritableBlocker::GetState(nsIPropertyBag** aBagOut) {
+  MOZ_ASSERT(aBagOut);
+
+  nsCOMPtr<nsIWritablePropertyBag2> propertyBag =
+      do_CreateInstance("@mozilla.org/hash-property-bag;1");
+
+  QM_TRY(OkIf(propertyBag), NS_ERROR_OUT_OF_MEMORY)
+
+  propertyBag.forget(aBagOut);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FileSystemWritableBlocker::BlockShutdown(
+    nsIAsyncShutdownClient* /* aBarrier */) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  return NS_OK;
+}
+
+class FileSystemNullBlocker : public FileSystemShutdownBlocker {
+ public:
+  NS_IMETHODIMP Block() override { return NS_OK; }
+
+  NS_IMETHODIMP Unblock() override { return NS_OK; }
+
+ protected:
+  virtual ~FileSystemNullBlocker() = default;
+};
+
+}  // namespace
+
+/* static */
+already_AddRefed<FileSystemShutdownBlocker>
+FileSystemShutdownBlocker::CreateForWritable() {
+// The shutdown blocker watches for xpcom-will-shutdown which is not fired
+// during content process shutdown in release builds.
+#ifdef DEBUG
+  if (NS_IsMainThread()) {
+    RefPtr<FileSystemShutdownBlocker> shutdownBlocker =
+        new FileSystemWritableBlocker();
+
+    return shutdownBlocker.forget();
+  }
+#endif
+
+  RefPtr<FileSystemShutdownBlocker> shutdownBlocker =
+      new FileSystemNullBlocker();
+
+  return shutdownBlocker.forget();
+}
+
+NS_IMPL_ISUPPORTS(FileSystemShutdownBlocker, nsIAsyncShutdownBlocker)
+
+/* nsIAsyncShutdownBlocker methods */
+NS_IMETHODIMP
+FileSystemShutdownBlocker::GetName(nsAString& /* aName */) { return NS_OK; }
+
+NS_IMETHODIMP
+FileSystemShutdownBlocker::GetState(nsIPropertyBag** /* aBagOut */) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FileSystemShutdownBlocker::BlockShutdown(
+    nsIAsyncShutdownClient* /* aBarrier */) {
+  return NS_OK;
+}
+
+}  // namespace mozilla::dom::fs