Bug 1657874 - Avoid some duplicate patterns to init cups shim. r=jwatt

Depends on D86336

Differential Revision: https://phabricator.services.mozilla.com/D86341

widget/nsCUPSShim.h

@@ -1,5 +1,5 @@
-/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* ex: set tabstop=8 softtabstop=4 shiftwidth=4 expandtab: */
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ex: set tabstop=8 softtabstop=2 shiftwidth=2 expandtab: */
 /* 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/. */
@@ -30,6 +30,10 @@ class nsCUPSShim {
    */
   bool IsInitialized() const { return mInited; }
 
+  bool EnsureInitialized() {
+    return IsInitialized() || Init();
+  }
+
   /**
    * Function pointers for supported functions. These are only
    * valid after successful initialization.

widget/nsPrinterListCUPS.cpp

@@ -13,10 +13,8 @@ static nsCUPSShim sCupsShim;
 
 NS_IMETHODIMP
 nsPrinterListCUPS::GetPrinters(nsTArray<RefPtr<nsIPrinter>>& aPrinters) {
-  if (!sCupsShim.IsInitialized()) {
-    if (!sCupsShim.Init()) {
-      return NS_ERROR_FAILURE;
-    }
+  if (!sCupsShim.EnsureInitialized()) {
+    return NS_ERROR_FAILURE;
   }
 
   mozilla::CUPSPrinterList cupsPrinterList(sCupsShim);
@@ -39,10 +37,8 @@ nsPrinterListCUPS::GetPrinters(nsTArray<RefPtr<nsIPrinter>>& aPrinters) {
 
 NS_IMETHODIMP
 nsPrinterListCUPS::GetSystemDefaultPrinterName(nsAString& aName) {
-  if (!sCupsShim.IsInitialized()) {
-    if (!sCupsShim.Init()) {
-      return NS_ERROR_FAILURE;
-    }
+  if (!sCupsShim.EnsureInitialized()) {
+    return NS_ERROR_FAILURE;
   }
 
   mozilla::CUPSPrinterList cupsPrinterList(sCupsShim);