Unifying NativeMetafile class interface (as much as possible) for Linux, Mac, Win

printing/native_metafile_linux.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 PRINTING_NATIVE_METAFILE_LINUX_H_
-#define PRINTING_NATIVE_METAFILE_LINUX_H_
-
-#include "base/basictypes.h"
-
-typedef struct _cairo_surface cairo_surface_t;
-typedef struct _cairo cairo_t;
-
-namespace base {
-struct FileDescriptor;
-}
-
-class FilePath;
-
-namespace printing {
-
-// This class is used to generate a PDF stream and to  store rendering results
-// in a string buffer.
-class NativeMetafile {
- public:
-  virtual ~NativeMetafile() {}
-
-  // Initializes to a fresh new metafile. Returns true on success.
-  // Note: It should only be called from the renderer process to allocate
-  // rendering resources.
-  virtual bool Init() = 0;
-
-  // Initializes a copy of metafile from PDF stream data.
-  // Returns true on success.
-  // |src_buffer| should point to the shared memory which stores PDF
-  // contents generated in the renderer.
-  // Note: It should only be called from the browser process to initialize
-  // |data_|.
-  virtual bool Init(const void* src_buffer, uint32 src_buffer_size) = 0;
-
-  // Sets raw PDF data for the document. This is used when a cairo drawing
-  // surface has already been created. This method will cause all subsequent
-  // drawing on the surface to be discarded (in Close()). If Init() has not yet
-  // been called this method simply calls the second version of Init.
-  virtual bool SetRawData(const void* src_buffer, uint32 src_buffer_size) = 0;
-
-  // Prepares a new cairo surface/context for rendering a new page.
-  // The unit is in point (=1/72 in).
-  // Returns NULL when failed.
-  virtual cairo_t* StartPage(double width_in_points,
-                             double height_in_points,
-                             double margin_top_in_points,
-                             double margin_right_in_points,
-                             double margin_bottom_in_points,
-                             double margin_left_in_points) = 0;
-
-  // Destroys the surface and the context used in rendering current page.
-  // The results of current page will be appended into buffer |data_|.
-  // Returns true on success.
-  virtual bool FinishPage() = 0;
-
-  // Closes resulting PDF file. No further rendering is allowed.
-  virtual void Close() = 0;
-
-  // Returns size of PDF contents stored in buffer |data_|.
-  // This function should ONLY be called after PDF file is closed.
-  virtual uint32 GetDataSize() const = 0;
-
-  // Copies PDF contents stored in buffer |data_| into |dst_buffer|.
-  // This function should ONLY be called after PDF file is closed.
-  // Returns true only when success.
-  virtual bool GetData(void* dst_buffer, uint32 dst_buffer_size) const = 0;
-
-  // Saves PDF contents stored in buffer |data_| into the file
-  // associated with |fd|.
-  // This function should ONLY be called after PDF file is closed.
-  virtual bool SaveTo(const base::FileDescriptor& fd) const = 0;
-};
-
-}  // namespace printing
-
-#endif  // PRINTING_NATIVE_METAFILE_LINUX_H_