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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 #include "androidfw/Source.h"
26 #include "io/Data.h"
27 #include "util/Files.h"
28 #include "util/Util.h"
29 
30 namespace aapt {
31 namespace io {
32 
33 // Interface for a file, which could be a real file on the file system, or a
34 // file inside a ZIP archive.
35 class IFile {
36  public:
37   virtual ~IFile() = default;
38 
39   // Open the file and return it as a block of contiguous memory. How this
40   // occurs is implementation dependent. For example, if this is a file on the file
41   // system, it may simply mmap the contents. If this file represents a compressed file in a
42   // ZIP archive, it may need to inflate it to memory, incurring a copy.
43   // Returns nullptr on failure.
44   virtual std::unique_ptr<IData> OpenAsData() = 0;
45 
46   virtual std::unique_ptr<android::InputStream> OpenInputStream() = 0;
47 
48   // Returns the source of this file. This is for presentation to the user and
49   // may not be a valid file system path (for example, it may contain a '@' sign to separate
50   // the files within a ZIP archive from the path to the containing ZIP archive.
51   virtual const android::Source& GetSource() const = 0;
52 
53   IFile* CreateFileSegment(size_t offset, size_t len);
54 
55   // Returns whether the file was compressed before it was stored in memory.
WasCompressed()56   virtual bool WasCompressed() {
57     return false;
58   }
59 
60   // Fills in buf with the last modification time of the file. Returns true if successful,
61   // otherwise false (i.e., the operation is not supported or the file system is unable to provide
62   // a last modification time).
63   virtual bool GetModificationTime(struct tm* buf) const = 0;
64 
65  private:
66   // Any segments created from this IFile need to be owned by this IFile, so
67   // keep them
68   // in a list. This will never be read, so we prefer better insertion
69   // performance
70   // than cache locality, hence the list.
71   std::list<std::unique_ptr<IFile>> segments_;
72 };
73 
74 // An IFile that wraps an underlying IFile but limits it to a subsection of that file.
75 class FileSegment : public IFile {
76  public:
FileSegment(IFile * file,size_t offset,size_t len)77   explicit FileSegment(IFile* file, size_t offset, size_t len)
78       : file_(file), offset_(offset), len_(len) {}
79 
80   std::unique_ptr<IData> OpenAsData() override;
81   std::unique_ptr<android::InputStream> OpenInputStream() override;
82 
GetSource()83   const android::Source& GetSource() const override {
84     return file_->GetSource();
85   }
86 
GetModificationTime(struct tm * buf)87   bool GetModificationTime(struct tm* buf) const override {
88     return file_->GetModificationTime(buf);
89   };
90 
91  private:
92   DISALLOW_COPY_AND_ASSIGN(FileSegment);
93 
94   IFile* file_;
95   size_t offset_;
96   size_t len_;
97 };
98 
99 class IFileCollectionIterator {
100  public:
101   virtual ~IFileCollectionIterator() = default;
102 
103   virtual bool HasNext() = 0;
104   virtual IFile* Next() = 0;
105 };
106 
107 // Interface for a collection of files, all of which share a common source. That source may
108 // simply be the filesystem, or a ZIP archive.
109 class IFileCollection {
110  public:
111   virtual ~IFileCollection() = default;
112 
113   virtual IFile* FindFile(android::StringPiece path) = 0;
114   virtual std::unique_ptr<IFileCollectionIterator> Iterator() = 0;
115   virtual char GetDirSeparator() = 0;
116 };
117 
118 }  // namespace io
119 }  // namespace aapt
120 
121 #endif /* AAPT_IO_FILE_H */
122