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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 // DataPack represents a read-only view onto an on-disk file that contains
      6 // (key, value) pairs of data.  It's used to store static resources like
      7 // translation strings and images.
      8 
      9 #ifndef UI_BASE_RESOURCE_DATA_PACK_H_
     10 #define UI_BASE_RESOURCE_DATA_PACK_H_
     11 
     12 #include <map>
     13 
     14 #include "base/basictypes.h"
     15 #include "base/files/file.h"
     16 #include "base/files/memory_mapped_file.h"
     17 #include "base/memory/scoped_ptr.h"
     18 #include "base/strings/string_piece.h"
     19 #include "ui/base/layout.h"
     20 #include "ui/base/resource/resource_handle.h"
     21 #include "ui/base/ui_base_export.h"
     22 
     23 namespace base {
     24 class FilePath;
     25 class RefCountedStaticMemory;
     26 }
     27 
     28 namespace ui {
     29 
     30 class UI_BASE_EXPORT DataPack : public ResourceHandle {
     31  public:
     32   DataPack(ui::ScaleFactor scale_factor);
     33   virtual ~DataPack();
     34 
     35   // Load a pack file from |path|, returning false on error.
     36   bool LoadFromPath(const base::FilePath& path);
     37 
     38   // Loads a pack file from |file|, returning false on error.
     39   bool LoadFromFile(base::File file);
     40 
     41   // Loads a pack file from |region| of |file|, returning false on error.
     42   bool LoadFromFileRegion(base::File file,
     43                           const base::MemoryMappedFile::Region& region);
     44 
     45   // Writes a pack file containing |resources| to |path|. If there are any
     46   // text resources to be written, their encoding must already agree to the
     47   // |textEncodingType| specified. If no text resources are present, please
     48   // indicate BINARY.
     49   static bool WritePack(const base::FilePath& path,
     50                         const std::map<uint16, base::StringPiece>& resources,
     51                         TextEncodingType textEncodingType);
     52 
     53   // ResourceHandle implementation:
     54   virtual bool HasResource(uint16 resource_id) const OVERRIDE;
     55   virtual bool GetStringPiece(uint16 resource_id,
     56                               base::StringPiece* data) const OVERRIDE;
     57   virtual base::RefCountedStaticMemory* GetStaticMemory(
     58       uint16 resource_id) const OVERRIDE;
     59   virtual TextEncodingType GetTextEncodingType() const OVERRIDE;
     60   virtual ui::ScaleFactor GetScaleFactor() const OVERRIDE;
     61 
     62  private:
     63   // Does the actual loading of a pack file. Called by Load and LoadFromFile.
     64   bool LoadImpl();
     65 
     66   // The memory-mapped data.
     67   scoped_ptr<base::MemoryMappedFile> mmap_;
     68 
     69   // Number of resources in the data.
     70   size_t resource_count_;
     71 
     72   // Type of encoding for text resources.
     73   TextEncodingType text_encoding_type_;
     74 
     75   // The scale of the image in this resource pack relative to images in the 1x
     76   // resource pak.
     77   ui::ScaleFactor scale_factor_;
     78 
     79   DISALLOW_COPY_AND_ASSIGN(DataPack);
     80 };
     81 
     82 }  // namespace ui
     83 
     84 #endif  // UI_BASE_RESOURCE_DATA_PACK_H_
     85