text: // 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.
  
  // DataPack represents a read-only view onto an on-disk file that contains
  // (key, value) pairs of data.  It's used to store static resources like
  // translation strings and images.
  
  #ifndef UI_BASE_RESOURCE_DATA_PACK_H_
  #define UI_BASE_RESOURCE_DATA_PACK_H_
  
  #include <map>
  
  #include "base/basictypes.h"
  #include "base/files/file.h"
  #include "base/files/memory_mapped_file.h"
  #include "base/memory/scoped_ptr.h"
  #include "base/strings/string_piece.h"
  #include "ui/base/resource/resource_handle.h"
  #include "ui/base/ui_base_export.h"
  
  namespace base {
  class FilePath;
  class RefCountedStaticMemory;
  }
  
  namespace ui {
  enum ScaleFactor : int;
  
  class UI_BASE_EXPORT DataPack : public ResourceHandle {
   public:
    DataPack(ui::ScaleFactor scale_factor);
    ~DataPack() override;
  
    // Load a pack file from |path|, returning false on error.
    bool LoadFromPath(const base::FilePath& path);
  
    // Loads a pack file from |file|, returning false on error.
    bool LoadFromFile(base::File file);
  
    // Loads a pack file from |region| of |file|, returning false on error.
    bool LoadFromFileRegion(base::File file,
                            const base::MemoryMappedFile::Region& region);
  
    // Writes a pack file containing |resources| to |path|. If there are any
    // text resources to be written, their encoding must already agree to the
    // |textEncodingType| specified. If no text resources are present, please
    // indicate BINARY.
    static bool WritePack(const base::FilePath& path,
                          const std::map<uint16, base::StringPiece>& resources,
                          TextEncodingType textEncodingType);
  
    // ResourceHandle implementation:
    bool HasResource(uint16 resource_id) const override;
    bool GetStringPiece(uint16 resource_id,
                        base::StringPiece* data) const override;
    base::RefCountedStaticMemory* GetStaticMemory(
        uint16 resource_id) const override;
    TextEncodingType GetTextEncodingType() const override;
    ui::ScaleFactor GetScaleFactor() const override;
  
   private:
    // Does the actual loading of a pack file. Called by Load and LoadFromFile.
    bool LoadImpl();
  
    // The memory-mapped data.
    scoped_ptr<base::MemoryMappedFile> mmap_;
  
    // Number of resources in the data.
    size_t resource_count_;
  
    // Type of encoding for text resources.
    TextEncodingType text_encoding_type_;
  
    // The scale of the image in this resource pack relative to images in the 1x
    // resource pak.
    ui::ScaleFactor scale_factor_;
  
    DISALLOW_COPY_AND_ASSIGN(DataPack);
  };
  
  }  // namespace ui
  
  #endif  // UI_BASE_RESOURCE_DATA_PACK_H_
  