Bug 1181329 - Make DataStore available to privileged homescreen app, …

…r=fabrice

dom/datastore/DataStoreService.cpp

@@ -1195,8 +1195,41 @@ DataStoreService::CheckPermission(nsIPrincipal* aPrincipal)
     return false;
   }
 
-  // Only support DataStore API for certified apps for now.
-  return status == nsIPrincipal::APP_STATUS_CERTIFIED;
+  // Certified apps are always allowed.
+  if (status == nsIPrincipal::APP_STATUS_CERTIFIED) {
+    return true;
+  }
+
+  if (status != nsIPrincipal::APP_STATUS_PRIVILEGED) {
+    return false;
+  }
+
+  // Privileged apps are allowed if they are the homescreen.
+  nsAdoptingString homescreen =
+    Preferences::GetString("dom.mozApps.homescreenURL");
+  if (!homescreen) {
+    return false;
+  }
+
+  uint32_t appId;
+  nsresult rv = aPrincipal->GetAppId(&appId);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+
+  nsCOMPtr<nsIAppsService> appsService =
+    do_GetService("@mozilla.org/AppsService;1");
+  if (NS_WARN_IF(!appsService)) {
+    return false;
+  }
+
+  nsAutoString manifestURL;
+  rv = appsService->GetManifestURLByLocalId(appId, manifestURL);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+
+  return manifestURL.Equals(homescreen);
 }
 
 NS_IMETHODIMP