Bug 1531538 - Delay resolving the promise returned from requestStorageAccess when the automatic storage access grants are invoked; r=baku

Differential Revision: https://phabricator.services.mozilla.com/D21771

--HG--
extra : moz-landing-system : lando

dom/base/StorageAccessPermissionRequest.cpp

@@ -5,6 +5,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "StorageAccessPermissionRequest.h"
+#include "mozilla/StaticPrefs.h"
+#include <cstdlib>
 
 namespace mozilla {
 namespace dom {
@@ -39,6 +41,7 @@ NS_IMETHODIMP
 StorageAccessPermissionRequest::Cancel() {
   if (!mCallbackCalled) {
     mCallbackCalled = true;
+    mTimer = nullptr;
     mCancelCallback();
   }
   return NS_OK;
@@ -59,7 +62,20 @@ StorageAccessPermissionRequest::Allow(JS::HandleValue aChoices) {
       mAllowAnySiteCallback();
     } else if (choices.Length() == 1 &&
                choices[0].choice().EqualsLiteral("allow-auto-grant")) {
-      mAllowAutoGrantCallback();
+      unsigned simulatedDelay = CalculateSimulatedDelay();
+      if (simulatedDelay) {
+        MOZ_ASSERT(!mTimer);
+        RefPtr<StorageAccessPermissionRequest> self = this;
+        rv = NS_NewTimerWithFuncCallback(
+            getter_AddRefs(mTimer), CallAutoGrantCallback, this, simulatedDelay,
+            nsITimer::TYPE_ONE_SHOT, "DelayedAllowAutoGrantCallback");
+        if (NS_WARN_IF(NS_FAILED(rv))) {
+          return rv;
+        }
+        NS_ADDREF(this);
+      } else {
+        mAllowAutoGrantCallback();
+      }
     } else {
       mAllowCallback();
     }
@@ -88,5 +104,29 @@ StorageAccessPermissionRequest::Create(
   return request.forget();
 }
 
+unsigned StorageAccessPermissionRequest::CalculateSimulatedDelay() {
+  if (!StaticPrefs::dom_storage_access_auto_grants_delayed()) {
+    return 0;
+  }
+
+  // Generate a random time value that is at least 5 seconds and at most 15
+  // minutes.
+  std::srand(static_cast<unsigned>(PR_Now()));
+
+  const unsigned kMin = 5000;
+  const unsigned kMax = 6000;
+  const unsigned random = std::abs(std::rand());
+
+  return kMin + random % (kMax - kMin);
+}
+
+void StorageAccessPermissionRequest::CallAutoGrantCallback(nsITimer* aTimer,
+                                                           void* aClosure) {
+  auto self = static_cast<StorageAccessPermissionRequest*>(aClosure);
+  self->mAllowAutoGrantCallback();
+  self->mTimer = nullptr;
+  NS_RELEASE(self);
+}
+
 }  // namespace dom
 }  // namespace mozilla

dom/base/StorageAccessPermissionRequest.h

@@ -47,10 +47,15 @@ class StorageAccessPermissionRequest final
       CancelCallback&& aCancelCallback);
   ~StorageAccessPermissionRequest();
 
+  unsigned CalculateSimulatedDelay();
+
+  static void CallAutoGrantCallback(nsITimer* aTimer, void* aClosure);
+
   AllowCallback mAllowCallback;
   AllowAutoGrantCallback mAllowAutoGrantCallback;
   AllowAnySiteCallback mAllowAnySiteCallback;
   CancelCallback mCancelCallback;
+  nsCOMPtr<nsITimer> mTimer;
   nsTArray<PermissionRequest> mPermissionRequests;
   bool mCallbackCalled;
 };

modules/libpref/init/StaticPrefList.h

@@ -520,6 +520,12 @@ VARCACHE_PREF(
   bool, false
 )
 
+VARCACHE_PREF(
+  "dom.storage_access.auto_grants.delayed",
+   dom_storage_access_auto_grants_delayed,
+  bool, true
+)
+
 //---------------------------------------------------------------------------
 // Extension prefs
 //---------------------------------------------------------------------------

toolkit/components/antitracking/test/browser/browser_storageAccessDoorHanger.js

@@ -22,6 +22,7 @@ async function testDoorHanger(choice, showPrompt, useEscape, topPage, maxConcurr
     ["browser.contentblocking.allowlist.storage.enabled", true],
     [ContentBlocking.prefIntroCount, ContentBlocking.MAX_INTROS],
     ["dom.storage_access.auto_grants", true],
+    ["dom.storage_access.auto_grants.delayed", false],
     ["dom.storage_access.enabled", true],
     ["dom.storage_access.max_concurrent_auto_grants", maxConcurrent],
     ["dom.storage_access.prompt.testing", false],