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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