Improved resource management

printing/backend/print_backend_win.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "printing/backend/print_backend.h"
 
 #include <objidl.h>
 #include <winspool.h>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 113 matching lines @@
                                            error.Receive());
       DCHECK(SUCCEEDED(hr));
       if (FAILED(hr)) {
         return false;
       }
       hr = StreamOnHGlobalToString(print_capabilities_stream.get(),
                                    &printer_info->printer_capabilities);
       DCHECK(SUCCEEDED(hr));
       printer_info->caps_mime_type = "text/xml";
     }
-    // TODO(sanjeevr): Add ScopedPrinterHandle
-    HANDLE printer_handle = NULL;
-    OpenPrinter(const_cast<LPTSTR>(printer_name_wide.c_str()), &printer_handle,
-                NULL);
+    ScopedPrinterHandle printer_handle;
+    OpenPrinter(const_cast<LPTSTR>(printer_name_wide.c_str()),
+                printer_handle.Receive(), NULL);
     DCHECK(printer_handle);
-    if (printer_handle) {
+    if (printer_handle.IsValid()) {
       LONG devmode_size = DocumentProperties(
           NULL, printer_handle, const_cast<LPTSTR>(printer_name_wide.c_str()),
           NULL, NULL, 0);
       if (devmode_size <= 0)
         return false;
       scoped_array<BYTE> devmode_out_buffer(new BYTE[devmode_size]);
       DEVMODE* devmode_out =
           reinterpret_cast<DEVMODE*>(devmode_out_buffer.get());
       DocumentProperties(
           NULL, printer_handle, const_cast<LPTSTR>(printer_name_wide.c_str()),
           devmode_out, NULL, DM_OUT_BUFFER);
       base::win::ScopedComPtr<IStream> printer_defaults_stream;
       hr = CreateStreamOnHGlobal(NULL, TRUE,
                                  printer_defaults_stream.Receive());
       DCHECK(SUCCEEDED(hr));
       if (printer_defaults_stream) {
         hr = XPSModule::ConvertDevModeToPrintTicket(provider,
                                                     devmode_size,
                                                     devmode_out,
                                                     kPTJobScope,
                                                     printer_defaults_stream);
         DCHECK(SUCCEEDED(hr));
         if (SUCCEEDED(hr)) {
           hr = StreamOnHGlobalToString(printer_defaults_stream.get(),
                                        &printer_info->printer_defaults);
           DCHECK(SUCCEEDED(hr));
           printer_info->defaults_mime_type = "text/xml";
         }
       }
-      ClosePrinter(printer_handle);
     }
     XPSModule::CloseProvider(provider);
   }
   return true;
 }
 
 bool PrintBackendWin::IsValidPrinter(const std::string& printer_name) {
   std::wstring printer_name_wide = UTF8ToWide(printer_name);
-  HANDLE printer_handle = NULL;
-  OpenPrinter(const_cast<LPTSTR>(printer_name_wide.c_str()), &printer_handle,
-              NULL);
-  bool ret = false;
-  if (printer_handle) {
-    ret = true;
-    ClosePrinter(printer_handle);
-  }
-  return ret;
+  ScopedPrinterHandle printer_handle;
+  OpenPrinter(const_cast<LPTSTR>(printer_name_wide.c_str()),
+              printer_handle.Receive(), NULL);
+  return printer_handle.IsValid();
 }
 
 scoped_refptr<PrintBackend> PrintBackend::CreateInstance(
     const base::DictionaryValue* print_backend_settings) {
   return new PrintBackendWin;
 }
 
 }  // namespace printing