File.h revision ce5e56e243d262a9b65459c3bd0bb9eaadd40628 
1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef AAPT_IO_FILE_H
18#define AAPT_IO_FILE_H
19
20#include <list>
21#include <memory>
22#include <vector>
23
24#include "android-base/macros.h"
25
26#include "Source.h"
27#include "io/Data.h"
28#include "util/Util.h"
29
30namespace aapt {
31namespace io {
32
33/**
34 * Interface for a file, which could be a real file on the file system, or a
35 * file inside
36 * a ZIP archive.
37 */
38class IFile {
39 public:
40  virtual ~IFile() = default;
41
42  /**
43   * Open the file and return it as a block of contiguous memory. How this
44   * occurs is
45   * implementation dependent. For example, if this is a file on the file
46   * system, it may
47   * simply mmap the contents. If this file represents a compressed file in a
48   * ZIP archive,
49   * it may need to inflate it to memory, incurring a copy.
50   *
51   * Returns nullptr on failure.
52   */
53  virtual std::unique_ptr<IData> OpenAsData() = 0;
54
55  /**
56   * Returns the source of this file. This is for presentation to the user and
57   * may not be a
58   * valid file system path (for example, it may contain a '@' sign to separate
59   * the files within
60   * a ZIP archive from the path to the containing ZIP archive.
61   */
62  virtual const Source& GetSource() const = 0;
63
64  IFile* CreateFileSegment(size_t offset, size_t len);
65
66 private:
67  // Any segments created from this IFile need to be owned by this IFile, so
68  // keep them
69  // in a list. This will never be read, so we prefer better insertion
70  // performance
71  // than cache locality, hence the list.
72  std::list<std::unique_ptr<IFile>> segments_;
73};
74
75/**
76 * An IFile that wraps an underlying IFile but limits it to a subsection of that
77 * file.
78 */
79class FileSegment : public IFile {
80 public:
81  explicit FileSegment(IFile* file, size_t offset, size_t len)
82      : file_(file), offset_(offset), len_(len) {}
83
84  std::unique_ptr<IData> OpenAsData() override;
85
86  const Source& GetSource() const override { return file_->GetSource(); }
87
88 private:
89  DISALLOW_COPY_AND_ASSIGN(FileSegment);
90
91  IFile* file_;
92  size_t offset_;
93  size_t len_;
94};
95
96class IFileCollectionIterator {
97 public:
98  virtual ~IFileCollectionIterator() = default;
99
100  virtual bool HasNext() = 0;
101  virtual IFile* Next() = 0;
102};
103
104/**
105 * Interface for a collection of files, all of which share a common source. That
106 * source may
107 * simply be the filesystem, or a ZIP archive.
108 */
109class IFileCollection {
110 public:
111  virtual ~IFileCollection() = default;
112
113  virtual IFile* FindFile(const StringPiece& path) = 0;
114  virtual std::unique_ptr<IFileCollectionIterator> Iterator() = 0;
115};
116
117}  // namespace io
118}  // namespace aapt
119
120#endif /* AAPT_IO_FILE_H */
121