1 files changed, 97 insertions, 0 deletions
diff --git a/toolkit/components/antitracking/TemporaryAccessGrantObserver.cpp b/toolkit/components/antitracking/TemporaryAccessGrantObserver.cpp
new file mode 100644
index 0000000000..a22b0caee8
--- /dev/null
+++ b/toolkit/components/antitracking/TemporaryAccessGrantObserver.cpp
@@ -0,0 +1,97 @@
+/* -*- 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 "TemporaryAccessGrantObserver.h"
+
+#include "mozilla/PermissionManager.h"
+#include "mozilla/Services.h"
+#include "nsIObserverService.h"
+#include "nsTHashtable.h"
+#include "nsXULAppAPI.h"
+
+using namespace mozilla;
+
+UniquePtr<TemporaryAccessGrantObserver::ObserversTable>
+    TemporaryAccessGrantObserver::sObservers;
+
+TemporaryAccessGrantObserver::TemporaryAccessGrantObserver(
+    PermissionManager* aPM, nsIPrincipal* aPrincipal, const nsACString& aType)
+    : mPM(aPM), mPrincipal(aPrincipal), mType(aType) {
+  MOZ_ASSERT(XRE_IsParentProcess(),
+             "Enforcing temporary access grant lifetimes can only be done in "
+             "the parent process");
+}
+
+NS_IMPL_ISUPPORTS(TemporaryAccessGrantObserver, nsIObserver, nsINamed)
+
+// static
+void TemporaryAccessGrantObserver::Create(PermissionManager* aPM,
+                                          nsIPrincipal* aPrincipal,
+                                          const nsACString& aType) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  if (!sObservers) {
+    sObservers = MakeUnique<ObserversTable>();
+  }
+  sObservers->LookupOrInsertWith(
+      std::make_pair(nsCOMPtr<nsIPrincipal>(aPrincipal), nsCString(aType)),
+      [&]() -> nsCOMPtr<nsITimer> {
+        // Only create a new observer if we don't have a matching
+        // entry in our hashtable.
+        nsCOMPtr<nsITimer> timer;
+        RefPtr<TemporaryAccessGrantObserver> observer =
+            new TemporaryAccessGrantObserver(aPM, aPrincipal, aType);
+        nsresult rv = NS_NewTimerWithObserver(getter_AddRefs(timer), observer,
+                                              24 * 60 * 60 * 1000,  // 24 hours
+                                              nsITimer::TYPE_ONE_SHOT);
+
+        if (NS_SUCCEEDED(rv)) {
+          observer->SetTimer(timer);
+          return timer;
+        }
+        timer->Cancel();
+        return nullptr;
+      });
+}
+
+void TemporaryAccessGrantObserver::SetTimer(nsITimer* aTimer) {
+  mTimer = aTimer;
+  nsCOMPtr<nsIObserverService> observerService =
+      mozilla::services::GetObserverService();
+  if (observerService) {
+    observerService->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
+  }
+}
+
+NS_IMETHODIMP
+TemporaryAccessGrantObserver::Observe(nsISupports* aSubject, const char* aTopic,
+                                      const char16_t* aData) {
+  if (strcmp(aTopic, NS_TIMER_CALLBACK_TOPIC) == 0) {
+    Unused << mPM->RemoveFromPrincipal(mPrincipal, mType);
+
+    MOZ_ASSERT(sObservers);
+    sObservers->Remove(std::make_pair(mPrincipal, mType));
+  } else if (strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) {
+    nsCOMPtr<nsIObserverService> observerService =
+        mozilla::services::GetObserverService();
+    if (observerService) {
+      observerService->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID);
+    }
+    if (mTimer) {
+      mTimer->Cancel();
+      mTimer = nullptr;
+    }
+    sObservers.reset();
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TemporaryAccessGrantObserver::GetName(nsACString& aName) {
+  aName.AssignLiteral("TemporaryAccessGrantObserver");
+  return NS_OK;
+}