From bb3147ef68c22fcd4490eab4b3a2ca29c1031282 Mon Sep 17 00:00:00 2001
From: Honza Bambas <honzab.moz@firemni.cz>
Date: Fri, 5 Feb 2016 08:36:00 -0500
Subject: [PATCH] Bug 1237783 - Make sure we correctly turn off appcache.
 r=ehsan

---
 dom/webidl/Window.webidl                           |  2 +-
 uriloader/prefetch/nsOfflineCacheUpdateService.cpp | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/dom/webidl/Window.webidl b/dom/webidl/Window.webidl
index e61d8e5a6d8..12b18a151f5 100644
--- a/dom/webidl/Window.webidl
+++ b/dom/webidl/Window.webidl
@@ -69,7 +69,7 @@ typedef any Transferable;
 #ifdef HAVE_SIDEBAR
   [Replaceable, Throws] readonly attribute External external;
 #endif
-  [Throws] readonly attribute ApplicationCache applicationCache;
+  [Throws, Pref="browser.cache.offline.enable"] readonly attribute ApplicationCache applicationCache;
 
   // user prompts
   [Throws, UnsafeInPrerendering] void alert();
diff --git a/uriloader/prefetch/nsOfflineCacheUpdateService.cpp b/uriloader/prefetch/nsOfflineCacheUpdateService.cpp
index e9b2e53bb0d..f26fb136aa0 100644
--- a/uriloader/prefetch/nsOfflineCacheUpdateService.cpp
+++ b/uriloader/prefetch/nsOfflineCacheUpdateService.cpp
@@ -52,6 +52,7 @@ using namespace mozilla;
 using namespace mozilla::dom;
 
 static nsOfflineCacheUpdateService *gOfflineCacheUpdateService = nullptr;
+static bool sAllowOfflineCache = true;
 
 nsTHashtable<nsCStringHashKey>* nsOfflineCacheUpdateService::mAllowedDomains = nullptr;
 
@@ -247,6 +248,10 @@ nsOfflineCacheUpdateService::nsOfflineCacheUpdateService()
     , mUpdateRunning(false)
     , mLowFreeSpace(false)
 {
+    MOZ_ASSERT(NS_IsMainThread());
+    Preferences::AddBoolVarCache(&sAllowOfflineCache,
+                                 "browser.cache.offline.enable",
+                                 true);
 }
 
 nsOfflineCacheUpdateService::~nsOfflineCacheUpdateService()
@@ -605,6 +610,10 @@ OfflineAppPermForPrincipal(nsIPrincipal *aPrincipal,
 {
     *aAllowed = false;
 
+    if (!sAllowOfflineCache) {
+        return NS_OK;
+    }
+
     if (!aPrincipal)
         return NS_ERROR_INVALID_ARG;
 
@@ -696,6 +705,10 @@ nsOfflineCacheUpdateService::AllowOfflineApp(nsIPrincipal *aPrincipal)
 {
     nsresult rv;
 
+    if (!sAllowOfflineCache) {
+        return NS_ERROR_NOT_AVAILABLE;
+    }
+
     if (GeckoProcessType_Default != XRE_GetProcessType()) {
         ContentChild* child = ContentChild::GetSingleton();