Create a Factory for NativeMetafile.

printing/metafile_factory.h

+// 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.
+
+#ifndef METAFILE_FACTORY_H_

[vandebo (ex-Chrome), 2011/02/22 22:18:16]

PRINTING_NATIVE_METAFILE_FACTORY_H_

[dpapad, 2011/02/23 00:44:39]

Done.

+#define METAFILE_FACTORY_H_
+
+#include "base/basictypes.h"
+#include "printing/native_metafile.h"
+
+#if defined(OS_WIN)
+  #include "printing/emf_win.h"
+#elif defined(OS_MACOSX)
+  #include "printing/pdf_metafile_mac.h"
+#elif defined(OS_POSIX)
+  #include "printing/pdf_ps_metafile_cairo.h"
+#endif
+
+namespace printing {
+
+// This class is used to obtain pointers to NativeMetafile objects. It is the

[vandebo (ex-Chrome), 2011/02/22 22:18:16]

This comment can be improved; most readers will understand the concept of a
factory, however it might be useful to say why we are using a factory.

[dpapad, 2011/02/23 00:44:39]

Done.

+// only way to initialize such objects since their constructors are private.
+class MetafileFactory {

[vandebo (ex-Chrome), 2011/02/22 22:18:16]

NativeMetafileFactory

[dpapad, 2011/02/23 00:44:39]

Done.

+ public:
+  virtual ~MetafileFactory();

[vandebo (ex-Chrome), 2011/02/22 22:18:16]

Not necessary, as there is currently no way to create an instance of this class.

[dpapad, 2011/02/23 00:44:39]

Done.

+
+  // This method takes care of returning a pointer to the appropriate
+  // NativeMetafile object according to the platform.
+  static printing::NativeMetafile* GetMetafile();

[vandebo (ex-Chrome), 2011/02/22 22:18:16]

Get implies retrieval and not creation.  Since this instantiates a new object,
the name should indicate that it is making something.  CreateMetafile is a
reasonable choice.

[dpapad, 2011/02/23 00:44:39]

Done.

+
+#if defined(OS_LINUX)
+  static printing::NativeMetafile*
+    GetMetafileFrom(cairo_t* context);
+#endif
+
+ private:
+  MetafileFactory();
+  DISALLOW_COPY_AND_ASSIGN(MetafileFactory);
+};
+
+}  // namespace printing
+
+#endif /* METAFILE_FACTORY_H_ */