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/memory/scoped_vector.h"
  19 #include "base/strings/string_piece.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 enum ScaleFactor : int;
  30
  31 class UI_BASE_EXPORT DataPack : public ResourceHandle {
  32  public:
  33   explicit DataPack(ui::ScaleFactor scale_factor);
  34   ~DataPack() override;
  35
  36   void set_has_only_material_design_assets(bool has_only_material_assets) {
  37     has_only_material_design_assets_ = has_only_material_assets;
  38   }
  39
  40   // Load a pack file from |path|, returning false on error.
  41   bool LoadFromPath(const base::FilePath& path);
  42
  43   // Loads a pack file from |file|, returning false on error.
  44   bool LoadFromFile(base::File file);
  45
  46   // Loads a pack file from |region| of |file|, returning false on error.
  47   bool LoadFromFileRegion(base::File file,
  48                           const base::MemoryMappedFile::Region& region);
  49
  50   // Writes a pack file containing |resources| to |path|. If there are any
  51   // text resources to be written, their encoding must already agree to the
  52   // |textEncodingType| specified. If no text resources are present, please
  53   // indicate BINARY.
  54   static bool WritePack(const base::FilePath& path,
  55                         const std::map<uint16, base::StringPiece>& resources,
  56                         TextEncodingType textEncodingType);
  57
  58   // ResourceHandle implementation:
  59   bool HasResource(uint16 resource_id) const override;
  60   bool GetStringPiece(uint16 resource_id,
  61                       base::StringPiece* data) const override;
  62   base::RefCountedStaticMemory* GetStaticMemory(
  63       uint16 resource_id) const override;
  64   TextEncodingType GetTextEncodingType() const override;
  65   ui::ScaleFactor GetScaleFactor() const override;
  66   bool HasOnlyMaterialDesignAssets() const override;
  67
  68 #if DCHECK_IS_ON()
  69   // Checks to see if any resource in this DataPack already exists in the list
  70   // of resources.
  71   void CheckForDuplicateResources(const ScopedVector<ResourceHandle>& packs);
  72 #endif
  73
  74  private:
  75   // Does the actual loading of a pack file. Called by Load and LoadFromFile.
  76   bool LoadImpl();
  77
  78   // The memory-mapped data.
  79   scoped_ptr<base::MemoryMappedFile> mmap_;
  80
  81   // Number of resources in the data.
  82   size_t resource_count_;
  83
  84   // Type of encoding for text resources.
  85   TextEncodingType text_encoding_type_;
  86
  87   // The scale of the image in this resource pack relative to images in the 1x
  88   // resource pak.
  89   ui::ScaleFactor scale_factor_;
  90
  91   // Set to true if the only resources contained within this DataPack are
  92   // material design image assets.
  93   bool has_only_material_design_assets_;
  94
  95   DISALLOW_COPY_AND_ASSIGN(DataPack);
  96 };
  97
  98 }  // namespace ui
  99
 100 #endif  // UI_BASE_RESOURCE_DATA_PACK_H_