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