toolkit/components/antitracking/TemporaryAccessGrantObserver.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "TemporaryAccessGrantObserver.h"
   8
   9 #include "mozilla/PermissionManager.h"
  10 #include "mozilla/Services.h"
  11 #include "nsIObserverService.h"
  12 #include "nsTHashtable.h"
  13 #include "nsXULAppAPI.h"
  14
  15 using namespace mozilla;
  16
  17 StaticAutoPtr<TemporaryAccessGrantObserver::ObserversTable>
  18     TemporaryAccessGrantObserver::sObservers;
  19
  20 TemporaryAccessGrantObserver::TemporaryAccessGrantObserver(
  21     PermissionManager* aPM, nsIPrincipal* aPrincipal, const nsACString& aType)
  22     : mPM(aPM), mPrincipal(aPrincipal), mType(aType) {
  23   MOZ_ASSERT(XRE_IsParentProcess(),
  24              "Enforcing temporary access grant lifetimes can only be done in "
  25              "the parent process");
  26 }
  27
  28 NS_IMPL_ISUPPORTS(TemporaryAccessGrantObserver, nsIObserver, nsINamed)
  29
  30 // static
  31 void TemporaryAccessGrantObserver::Create(PermissionManager* aPM,
  32                                           nsIPrincipal* aPrincipal,
  33                                           const nsACString& aType) {
  34   MOZ_ASSERT(XRE_IsParentProcess());
  35
  36   if (!sObservers) {
  37     sObservers = new ObserversTable();
  38   }
  39   sObservers->LookupOrInsertWith(
  40       std::make_pair(nsCOMPtr<nsIPrincipal>(aPrincipal), nsCString(aType)),
  41       [&]() -> nsCOMPtr<nsITimer> {
  42         // Only create a new observer if we don't have a matching
  43         // entry in our hashtable.
  44         nsCOMPtr<nsITimer> timer;
  45         RefPtr<TemporaryAccessGrantObserver> observer =
  46             new TemporaryAccessGrantObserver(aPM, aPrincipal, aType);
  47         nsresult rv = NS_NewTimerWithObserver(getter_AddRefs(timer), observer,
  48                                               24 * 60 * 60 * 1000,  // 24 hours
  49                                               nsITimer::TYPE_ONE_SHOT);
  50
  51         if (NS_SUCCEEDED(rv)) {
  52           observer->SetTimer(timer);
  53           return timer;
  54         }
  55         timer->Cancel();
  56         return nullptr;
  57       });
  58 }
  59
  60 void TemporaryAccessGrantObserver::SetTimer(nsITimer* aTimer) {
  61   mTimer = aTimer;
  62   nsCOMPtr<nsIObserverService> observerService =
  63       mozilla::services::GetObserverService();
  64   if (observerService) {
  65     observerService->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
  66   }
  67 }
  68
  69 NS_IMETHODIMP
  70 TemporaryAccessGrantObserver::Observe(nsISupports* aSubject, const char* aTopic,
  71                                       const char16_t* aData) {
  72   if (strcmp(aTopic, NS_TIMER_CALLBACK_TOPIC) == 0) {
  73     Unused << mPM->RemoveFromPrincipal(mPrincipal, mType);
  74
  75     MOZ_ASSERT(sObservers);
  76     sObservers->Remove(std::make_pair(mPrincipal, mType));
  77   } else if (strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) {
  78     nsCOMPtr<nsIObserverService> observerService =
  79         mozilla::services::GetObserverService();
  80     if (observerService) {
  81       observerService->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID);
  82     }
  83     if (mTimer) {
  84       mTimer->Cancel();
  85       mTimer = nullptr;
  86     }
  87     sObservers = nullptr;
  88   }
  89
  90   return NS_OK;
  91 }
  92
  93 NS_IMETHODIMP
  94 TemporaryAccessGrantObserver::GetName(nsACString& aName) {
  95   aName.AssignLiteral("TemporaryAccessGrantObserver");
  96   return NS_OK;
  97 }