chrome/browser/printing/print_preview_data_service.h

// Copyright (c) 2012 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 CHROME_BROWSER_PRINTING_PRINT_PREVIEW_DATA_SERVICE_H_
#define CHROME_BROWSER_PRINTING_PRINT_PREVIEW_DATA_SERVICE_H_

#include <map>
#include <string>

#include "base/memory/ref_counted.h"

class PrintPreviewDataStore;

namespace base {
template <typename T>
struct DefaultSingletonTraits;
class RefCountedBytes;
}

// PrintPreviewDataService manages data stores for chrome://print requests.
// It owns the data store object and is responsible for freeing it.
class PrintPreviewDataService {
 public:
  static PrintPreviewDataService* GetInstance();

  // Get the data entry from PrintPreviewDataStore. |index| is zero-based or
  // |printing::COMPLETE_PREVIEW_DOCUMENT_INDEX| to represent complete preview
  // data. Use |index| to retrieve a specific preview page data. |data| is set
  // to NULL if the requested page is not yet available.
  void GetDataEntry(int32_t preview_ui_id, int index,
                    scoped_refptr<base::RefCountedBytes>* data);

  // Set/Update the data entry in PrintPreviewDataStore. |index| is zero-based
  // or |printing::COMPLETE_PREVIEW_DOCUMENT_INDEX| to represent complete
  // preview data. Use |index| to set/update a specific preview page data.
  // NOTE: PrintPreviewDataStore owns the data. Do not refcount |data| before
  // calling this function. It will be refcounted in PrintPreviewDataStore.
  void SetDataEntry(int32_t preview_ui_id, int index,
                    const base::RefCountedBytes* data);

  // Remove the corresponding PrintPreviewUI entry from the map.
  void RemoveEntry(int32_t preview_ui_id);

  // Returns the available draft page count.
  int GetAvailableDraftPageCount(int32_t preview_ui_id);

 private:
  friend struct base::DefaultSingletonTraits<PrintPreviewDataService>;

  // 1:1 relationship between PrintPreviewUI and data store object.
  // Key: PrintPreviewUI ID.
  // Value: Print preview data store object.
  using PreviewDataStoreMap =
      std::map<int32_t, scoped_refptr<PrintPreviewDataStore>>;

  PrintPreviewDataService();
  virtual ~PrintPreviewDataService();

  PreviewDataStoreMap data_store_map_;

  DISALLOW_COPY_AND_ASSIGN(PrintPreviewDataService);
};

#endif  // CHROME_BROWSER_PRINTING_PRINT_PREVIEW_DATA_SERVICE_H_