1 files changed, 110 insertions, 0 deletions
diff --git a/dom/workers/WorkerDocumentListener.cpp b/dom/workers/WorkerDocumentListener.cpp
new file mode 100644
index 0000000000..dfc8544daf
--- /dev/null
+++ b/dom/workers/WorkerDocumentListener.cpp
@@ -0,0 +1,110 @@
+/* -*- 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 "WorkerDocumentListener.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/WorkerPrivate.h"
+#include "mozilla/dom/WorkerRef.h"
+#include "mozilla/dom/WorkerRunnable.h"
+#include "mozilla/dom/WorkerScope.h"
+#include "nsGlobalWindowInner.h"
+
+namespace mozilla::dom {
+
+WorkerDocumentListener::WorkerDocumentListener()
+    : mMutex("mozilla::dom::WorkerDocumentListener::mMutex") {}
+
+WorkerDocumentListener::~WorkerDocumentListener() = default;
+
+RefPtr<WorkerDocumentListener> WorkerDocumentListener::Create(
+    WorkerPrivate* aWorkerPrivate) {
+  MOZ_ASSERT(aWorkerPrivate);
+  aWorkerPrivate->AssertIsOnWorkerThread();
+
+  auto listener = MakeRefPtr<WorkerDocumentListener>();
+
+  RefPtr<StrongWorkerRef> strongWorkerRef =
+      StrongWorkerRef::Create(aWorkerPrivate, "WorkerDocumentListener",
+                              [listener]() { listener->Destroy(); });
+  if (NS_WARN_IF(!strongWorkerRef)) {
+    return nullptr;
+  }
+
+  listener->mWorkerRef = new ThreadSafeWorkerRef(strongWorkerRef);
+  uint64_t windowID = aWorkerPrivate->WindowID();
+
+  aWorkerPrivate->DispatchToMainThread(NS_NewRunnableFunction(
+      "WorkerDocumentListener::Create",
+      [listener, windowID] { listener->SetListening(windowID, true); }));
+
+  return listener;
+}
+
+void WorkerDocumentListener::OnVisible(bool aVisible) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  MutexAutoLock lock(mMutex);
+  if (!mWorkerRef) {
+    // We haven't handled the runnable to release this yet.
+    return;
+  }
+
+  class VisibleRunnable final : public WorkerRunnable {
+   public:
+    VisibleRunnable(WorkerPrivate* aWorkerPrivate, bool aVisible)
+        : WorkerRunnable(aWorkerPrivate), mVisible(aVisible) {}
+
+    bool WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) {
+      WorkerGlobalScope* scope = aWorkerPrivate->GlobalScope();
+      MOZ_ASSERT(scope);
+      scope->OnDocumentVisible(mVisible);
+      return true;
+    }
+
+   private:
+    const bool mVisible;
+  };
+
+  auto runnable = MakeRefPtr<VisibleRunnable>(mWorkerRef->Private(), aVisible);
+  runnable->Dispatch();
+}
+
+void WorkerDocumentListener::SetListening(uint64_t aWindowID, bool aListen) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  auto* window = nsGlobalWindowInner::GetInnerWindowWithId(aWindowID);
+  Document* doc = window->GetExtantDoc();
+  if (NS_WARN_IF(!doc)) {
+    // This would typically happen during shutdown if there is an active worker
+    // listening for document events. The Document may already be freed when we
+    // try to deregister for notifications.
+    return;
+  }
+
+  if (aListen) {
+    doc->AddWorkerDocumentListener(this);
+  } else {
+    doc->RemoveWorkerDocumentListener(this);
+  }
+}
+
+void WorkerDocumentListener::Destroy() {
+  MutexAutoLock lock(mMutex);
+
+  MOZ_ASSERT(mWorkerRef);
+  WorkerPrivate* workerPrivate = mWorkerRef->Private();
+  MOZ_ASSERT(workerPrivate);
+  workerPrivate->AssertIsOnWorkerThread();
+
+  uint64_t windowID = workerPrivate->WindowID();
+  workerPrivate->DispatchToMainThread(NS_NewRunnableFunction(
+      "WorkerDocumentListener::Destroy", [self = RefPtr{this}, windowID] {
+        self->SetListening(windowID, false);
+      }));
+  mWorkerRef = nullptr;
+}
+
+}  // namespace mozilla::dom