zip.h revision 89b255ab712cb7c93e99799fb2216f81e8391730
1// Copyright 2015 Google Inc. All rights reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//    http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14//
15// zip.h -- .zip (.jar) file reading/writing routines.
16//
17// This file specifies the interface to use the ZIP implementation of ijar.
18//
19
20#ifndef INCLUDED_THIRD_PARTY_IJAR_ZIP_H
21#define INCLUDED_THIRD_PARTY_IJAR_ZIP_H
22
23#include <sys/stat.h>
24
25#include "common.h"
26
27namespace devtools_ijar {
28
29// Tells if this is a directory entry from the mode. This method
30// is safer than zipattr_to_mode(attr) & S_IFDIR because the unix
31// mode might not be set in DOS zip files.
32inline bool zipattr_is_dir(u4 attr) { return (attr & 0x10) != 0; }
33
34// Convert a Unix file mode to a ZIP file attribute
35inline u4 mode_to_zipattr(mode_t m) {
36  return (((u4) m) << 16) + ((m & S_IFDIR) != 0 ? 0x10 : 0);
37}
38
39// Convert a ZIP file attribute to a Unix file mode
40inline mode_t zipattr_to_mode(u4 attr) {
41  return ((mode_t) ((attr >> 16) & 0xffff));
42}
43
44//
45// Class interface for building ZIP files
46//
47class ZipBuilder {
48 public:
49  virtual ~ZipBuilder() {}
50
51  // Returns the text for the last error, or null on no last error.
52  virtual const char* GetError() = 0;
53
54  // Add a new file to the ZIP, the file will have path "filename"
55  // and external attributes "attr". This function returns a pointer
56  // to a memory buffer to write the data of the file into. This buffer
57  // is owned by ZipBuilder and should not be free'd by the caller. The
58  // file length is then specified when the files is finished written
59  // using the FinishFile(size_t) function.
60  // On failure, returns NULL and GetError() will return an non-empty message.
61  virtual u1* NewFile(const char* filename, const u4 attr) = 0;
62
63  // Finish writing a file and specify its length. After calling this method
64  // one should not reuse the pointer given by NewFile. The file can be
65  // compressed using the deflate algorithm by setting `compress` to true.
66  // By default, CRC32 are not computed as java tooling doesn't care, but
67  // computing it can be activated by setting `compute_crc` to true.
68  // On failure, returns -1 and GetError() will return an non-empty message.
69  virtual int FinishFile(size_t filelength,
70                         bool compress = false,
71                         bool compute_crc = false) = 0;
72
73  // Write an empty file, it is equivalent to:
74  //   NewFile(filename, 0);
75  //   FinishFile(0);
76  // On failure, returns -1 and GetError() will return an non-empty message.
77  virtual int WriteEmptyFile(const char* filename) = 0;
78
79  // Finish writing the ZIP file. This method can be called only once
80  // (subsequent calls will do nothing) and none of
81  // NewFile/FinishFile/WriteEmptyFile should be called after calling Finish. If
82  // this method was not called when the object is destroyed, it will be called.
83  // It is here as a convenience to get information on the final generated ZIP
84  // file.
85  // On failure, returns -1 and GetError() will return an non-empty message.
86  virtual int Finish() = 0;
87
88  // Get the current size of the ZIP file. This size will not be matching the
89  // final ZIP file until Finish() has been called because Finish() is actually
90  // writing the central directory of the ZIP File.
91  virtual size_t GetSize() = 0;
92
93  // Returns the current number of files stored in the ZIP.
94  virtual int GetNumberFiles() = 0;
95
96  // Create a new ZipBuilder writing the file zip_file and the size of the
97  // output will be at most estimated_size. Use ZipBuilder::EstimateSize() or
98  // ZipExtractor::CalculateOuputLength() to have an estimated_size depending on
99  // a list of file to store.
100  // On failure, returns NULL. Refer to errno for error code.
101  static ZipBuilder* Create(const char* zip_file, u8 estimated_size);
102
103  // Estimate the maximum size of the ZIP files containing files in the "files"
104  // null-terminated array.
105  // Returns 0 on error.
106  static u8 EstimateSize(char **files);
107};
108
109//
110// An abstract class to process data from a ZipExtractor.
111// Derive from this class if you wish to process data from a ZipExtractor.
112//
113class ZipExtractorProcessor {
114 public:
115  virtual ~ZipExtractorProcessor() {}
116
117  // Tells whether to skip or process the file "filename". "attr" is the
118  // external file attributes and can be converted to unix mode using the
119  // zipattr_to_mode() function. This method is suppoed to returns true
120  // if the file should be processed and false if it should be skipped.
121  virtual bool Accept(const char* filename, const u4 attr) = 0;
122
123  // Process a file accepted by Accept. The file "filename" has external
124  // attributes "attr" and length "size". The file content is accessible
125  // in the buffer pointed by "data".
126  virtual void Process(const char* filename, const u4 attr,
127                       const u1* data, const size_t size) = 0;
128};
129
130//
131// Class interface for reading ZIP files
132//
133class ZipExtractor {
134 public:
135  virtual ~ZipExtractor() {}
136
137  // Returns the text for the last error, or null on no last error.
138  virtual const char* GetError() = 0;
139
140  // Process the next files, returns false if the end of ZIP file has been
141  // reached. The processor provided by the Create method will be called
142  // if a file is encountered. If false is returned, check the return value
143  // of GetError() for potential errors.
144  virtual bool ProcessNext() = 0;
145
146  // Process the all files, returns -1 on error (GetError() will be populated
147  // on error).
148  virtual int ProcessAll();
149
150  // Reset the file pointer to the beginning.
151  virtual void Reset() = 0;
152
153  // Return the size of the ZIP file.
154  virtual size_t GetSize() = 0;
155
156  // Return the size of the resulting zip file by keeping only file
157  // accepted by the processor and storing them uncompressed. This
158  // method can be used to create a ZipBuilder for storing a subset
159  // of the input files.
160  // On error, 0 is returned and GetError() returns a non-empty message.
161  virtual u8 CalculateOutputLength() = 0;
162
163  // Create a ZipExtractor that extract the zip file "filename" and process
164  // it with "processor".
165  // On error, a null pointer is returned and the value of errno should be
166  // checked.
167  static ZipExtractor* Create(const char* filename,
168                              ZipExtractorProcessor *processor);
169};
170
171}  // namespace devtools_ijar
172
173#endif  // INCLUDED_THIRD_PARTY_IJAR_ZIP_H
174