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bae7f79e ILT |
1 | // fileread.h -- read files for gold -*- C++ -*- |
2 | ||
6cb15b7f ILT |
3 | // Copyright 2006, 2007 Free Software Foundation, Inc. |
4 | // Written by Ian Lance Taylor <iant@google.com>. | |
5 | ||
6 | // This file is part of gold. | |
7 | ||
8 | // This program is free software; you can redistribute it and/or modify | |
9 | // it under the terms of the GNU General Public License as published by | |
10 | // the Free Software Foundation; either version 3 of the License, or | |
11 | // (at your option) any later version. | |
12 | ||
13 | // This program is distributed in the hope that it will be useful, | |
14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | // GNU General Public License for more details. | |
17 | ||
18 | // You should have received a copy of the GNU General Public License | |
19 | // along with this program; if not, write to the Free Software | |
20 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, | |
21 | // MA 02110-1301, USA. | |
22 | ||
bae7f79e ILT |
23 | // Classes used to read data from binary input files. |
24 | ||
25 | #ifndef GOLD_FILEREAD_H | |
26 | #define GOLD_FILEREAD_H | |
27 | ||
bae7f79e | 28 | #include <list> |
ead1e424 ILT |
29 | #include <map> |
30 | #include <string> | |
bae7f79e ILT |
31 | |
32 | #include "options.h" | |
33 | ||
34 | namespace gold | |
35 | { | |
36 | ||
37 | class Dirsearch; | |
bae7f79e ILT |
38 | class File_view; |
39 | ||
40 | // File_read manages a file descriptor for a file we are reading. We | |
41 | // close file descriptors if we run out of them, so this class reopens | |
42 | // the file as needed. | |
43 | ||
44 | class File_read | |
45 | { | |
46 | public: | |
47 | File_read() | |
82dcae9d ILT |
48 | : name_(), descriptor_(-1), size_(0), lock_count_(0), views_(), |
49 | saved_views_(), contents_(NULL) | |
bae7f79e | 50 | { } |
5a6f7e2d | 51 | |
bae7f79e ILT |
52 | ~File_read(); |
53 | ||
54 | // Open a file. | |
55 | bool | |
56 | open(const std::string& name); | |
57 | ||
5a6f7e2d ILT |
58 | // Pretend to open the file, but provide the file contents. No |
59 | // actual file system activity will occur. This is used for | |
60 | // testing. | |
61 | bool | |
62 | open(const std::string& name, const unsigned char* contents, off_t size); | |
63 | ||
bae7f79e ILT |
64 | // Return the file name. |
65 | const std::string& | |
66 | filename() const | |
67 | { return this->name_; } | |
68 | ||
bae7f79e ILT |
69 | // Lock the file for access within a particular Task::run execution. |
70 | // This means that the descriptor can not be closed. This routine | |
71 | // may only be called from the main thread. | |
72 | void | |
73 | lock(); | |
74 | ||
75 | // Unlock the descriptor, permitting it to be closed if necessary. | |
76 | void | |
77 | unlock(); | |
4973341a | 78 | |
bae7f79e ILT |
79 | // Test whether the object is locked. |
80 | bool | |
81 | is_locked(); | |
82 | ||
82dcae9d ILT |
83 | // Return the size of the file. |
84 | off_t | |
85 | filesize() const | |
86 | { return this->size_; } | |
87 | ||
ba45d247 ILT |
88 | // Return a view into the file starting at file offset START for |
89 | // SIZE bytes. The pointer will remain valid until the File_read is | |
90 | // unlocked. It is an error if we can not read enough data from the | |
91 | // file. | |
bae7f79e | 92 | const unsigned char* |
ba45d247 | 93 | get_view(off_t start, off_t size); |
bae7f79e | 94 | |
ba45d247 ILT |
95 | // Read data from the file into the buffer P starting at file offset |
96 | // START for SIZE bytes. | |
97 | void | |
98 | read(off_t start, off_t size, void* p); | |
99 | ||
ba45d247 ILT |
100 | // Return a lasting view into the file starting at file offset START |
101 | // for SIZE bytes. This is allocated with new, and the caller is | |
102 | // responsible for deleting it when done. The data associated with | |
103 | // this view will remain valid until the view is deleted. It is an | |
104 | // error if we can not read enough data from the file. | |
bae7f79e | 105 | File_view* |
ba45d247 | 106 | get_lasting_view(off_t start, off_t size); |
bae7f79e ILT |
107 | |
108 | private: | |
109 | // This class may not be copied. | |
110 | File_read(const File_read&); | |
111 | File_read& operator=(const File_read&); | |
112 | ||
113 | // A view into the file when not using mmap. | |
114 | class View | |
115 | { | |
116 | public: | |
e214a02b | 117 | View(off_t start, off_t size, const unsigned char* data) |
bae7f79e ILT |
118 | : start_(start), size_(size), data_(data), lock_count_(0) |
119 | { } | |
120 | ||
121 | ~View(); | |
122 | ||
123 | off_t | |
124 | start() const | |
125 | { return this->start_; } | |
126 | ||
127 | off_t | |
128 | size() const | |
129 | { return this->size_; } | |
130 | ||
e214a02b | 131 | const unsigned char* |
bae7f79e ILT |
132 | data() const |
133 | { return this->data_; } | |
134 | ||
135 | void | |
136 | lock(); | |
137 | ||
138 | void | |
139 | unlock(); | |
140 | ||
141 | bool | |
142 | is_locked(); | |
143 | ||
144 | private: | |
145 | View(const View&); | |
146 | View& operator=(const View&); | |
147 | ||
148 | off_t start_; | |
149 | off_t size_; | |
e214a02b | 150 | const unsigned char* data_; |
bae7f79e ILT |
151 | int lock_count_; |
152 | }; | |
153 | ||
154 | friend class File_view; | |
155 | ||
ead1e424 | 156 | // Find a view into the file. |
bae7f79e ILT |
157 | View* |
158 | find_view(off_t start, off_t size); | |
159 | ||
ead1e424 | 160 | // Read data from the file into a buffer. |
bae7f79e | 161 | off_t |
82dcae9d ILT |
162 | do_read(off_t start, off_t size, void* p); |
163 | ||
164 | // Read an exact number of bytes into a buffer. | |
165 | void | |
166 | do_read_exact(off_t start, off_t size, void* p); | |
bae7f79e | 167 | |
ead1e424 | 168 | // Find or make a view into the file. |
bae7f79e | 169 | View* |
bae3688d | 170 | find_or_make_view(off_t start, off_t size); |
bae7f79e | 171 | |
ead1e424 | 172 | // Clear the file views. |
bae7f79e ILT |
173 | void |
174 | clear_views(bool); | |
175 | ||
ead1e424 ILT |
176 | // The size of a file page for buffering data. |
177 | static const off_t page_size = 8192; | |
178 | ||
179 | // Given a file offset, return the page offset. | |
180 | static off_t | |
181 | page_offset(off_t file_offset) | |
182 | { return file_offset & ~ (page_size - 1); } | |
183 | ||
184 | // Given a file size, return the size to read integral pages. | |
185 | static off_t | |
186 | pages(off_t file_size) | |
187 | { return (file_size + (page_size - 1)) & ~ (page_size - 1); } | |
188 | ||
189 | // The type of a mapping from page start to views. | |
190 | typedef std::map<off_t, View*> Views; | |
191 | ||
192 | // A simple list of Views. | |
193 | typedef std::list<View*> Saved_views; | |
194 | ||
195 | // File name. | |
bae7f79e | 196 | std::string name_; |
ead1e424 | 197 | // File descriptor. |
bae7f79e | 198 | int descriptor_; |
82dcae9d ILT |
199 | // File size. |
200 | off_t size_; | |
ead1e424 | 201 | // Number of locks on the file. |
bae7f79e | 202 | int lock_count_; |
ead1e424 ILT |
203 | // Buffered views into the file. |
204 | Views views_; | |
205 | // List of views which were locked but had to be removed from views_ | |
206 | // because they were not large enough. | |
207 | Saved_views saved_views_; | |
5a6f7e2d ILT |
208 | // Specified file contents. Used only for testing purposes. |
209 | const unsigned char* contents_; | |
bae7f79e ILT |
210 | }; |
211 | ||
212 | // A view of file data that persists even when the file is unlocked. | |
213 | // Callers should destroy these when no longer required. These are | |
214 | // obtained form File_read::get_lasting_view. They may only be | |
215 | // destroyed when the underlying File_read is locked. | |
216 | ||
217 | class File_view | |
218 | { | |
219 | public: | |
220 | // This may only be called when the underlying File_read is locked. | |
221 | ~File_view(); | |
222 | ||
223 | // Return a pointer to the data associated with this view. | |
224 | const unsigned char* | |
225 | data() const | |
226 | { return this->data_; } | |
227 | ||
228 | private: | |
229 | File_view(const File_view&); | |
230 | File_view& operator=(const File_view&); | |
231 | ||
232 | friend class File_read; | |
233 | ||
234 | // Callers have to get these via File_read::get_lasting_view. | |
235 | File_view(File_read& file, File_read::View* view, const unsigned char* data) | |
236 | : file_(file), view_(view), data_(data) | |
237 | { } | |
238 | ||
239 | File_read& file_; | |
240 | File_read::View* view_; | |
241 | const unsigned char* data_; | |
242 | }; | |
243 | ||
bae7f79e ILT |
244 | // All the information we hold for a single input file. This can be |
245 | // an object file, a shared library, or an archive. | |
246 | ||
247 | class Input_file | |
248 | { | |
249 | public: | |
5a6f7e2d ILT |
250 | Input_file(const Input_file_argument* input_argument) |
251 | : input_argument_(input_argument), file_() | |
bae7f79e ILT |
252 | { } |
253 | ||
5a6f7e2d ILT |
254 | // Create an input file with the contents already provided. This is |
255 | // only used for testing. With this path, don't call the open | |
256 | // method. | |
257 | Input_file(const char* name, const unsigned char* contents, off_t size); | |
258 | ||
259 | // Open the file. | |
bae7f79e ILT |
260 | void |
261 | open(const General_options&, const Dirsearch&); | |
262 | ||
263 | // Return the name given by the user. | |
264 | const char* | |
265 | name() const | |
5a6f7e2d | 266 | { return this->input_argument_->name(); } |
bae7f79e ILT |
267 | |
268 | // Return the file name. | |
269 | const std::string& | |
270 | filename() const | |
271 | { return this->file_.filename(); } | |
272 | ||
4973341a ILT |
273 | // Return the position dependent options. |
274 | const Position_dependent_options& | |
275 | options() const | |
276 | { return this->input_argument_->options(); } | |
277 | ||
278 | // Return the file. | |
bae7f79e ILT |
279 | File_read& |
280 | file() | |
281 | { return this->file_; } | |
282 | ||
283 | private: | |
ead1e424 ILT |
284 | Input_file(const Input_file&); |
285 | Input_file& operator=(const Input_file&); | |
286 | ||
5a6f7e2d | 287 | const Input_file_argument* input_argument_; |
bae7f79e ILT |
288 | File_read file_; |
289 | }; | |
290 | ||
291 | } // end namespace gold | |
292 | ||
293 | #endif // !defined(GOLD_FILEREAD_H) |