ui/base/resource/data_pack.h

   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/resource/resource_handle.h"
  20 #include "ui/base/ui_base_export.h"
  21
  22 namespace base {
  23 class FilePath;
  24 class RefCountedStaticMemory;
  25 }
  26
  27 namespace ui {
  28 enum ScaleFactor : int;
  29
  30 class UI_BASE_EXPORT DataPack : public ResourceHandle {
  31  public:
  32   explicit DataPack(ui::ScaleFactor scale_factor);
  33   ~DataPack() override;
  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   bool HasResource(uint16 resource_id) const override;
  55   bool GetStringPiece(uint16 resource_id,
  56                       base::StringPiece* data) const override;
  57   base::RefCountedStaticMemory* GetStaticMemory(
  58       uint16 resource_id) const override;
  59   TextEncodingType GetTextEncodingType() const override;
  60   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_