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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() | |
5a6f7e2d ILT |
48 | : name_(), descriptor_(-1), lock_count_(0), views_(), |
49 | saved_views_(), contents_(NULL), contents_size_(0) | |
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 | ||
83 | // Return a view into the file. The pointer will remain valid until | |
84 | // the File_read is unlocked. If PBYTES is NULL, it is an error if | |
85 | // we can not read enough data. Otherwise *PBYTES is set to the | |
86 | // number of bytes read. | |
87 | const unsigned char* | |
4973341a | 88 | get_view(off_t start, off_t size, off_t* pbytes = NULL); |
bae7f79e ILT |
89 | |
90 | // Read data from the file into the buffer P. PBYTES is as in | |
91 | // get_view. | |
92 | void | |
4973341a | 93 | read(off_t start, off_t size, void* p, off_t* pbytes = NULL); |
bae7f79e ILT |
94 | |
95 | // Return a lasting view into the file. This is allocated with new, | |
96 | // and the caller is responsible for deleting it when done. The | |
97 | // data associated with this view will remain valid until the view | |
98 | // is deleted. PBYTES is handled as with get_view. | |
99 | File_view* | |
100 | get_lasting_view(off_t start, off_t size, off_t *pbytes = NULL); | |
101 | ||
102 | private: | |
103 | // This class may not be copied. | |
104 | File_read(const File_read&); | |
105 | File_read& operator=(const File_read&); | |
106 | ||
107 | // A view into the file when not using mmap. | |
108 | class View | |
109 | { | |
110 | public: | |
e214a02b | 111 | View(off_t start, off_t size, const unsigned char* data) |
bae7f79e ILT |
112 | : start_(start), size_(size), data_(data), lock_count_(0) |
113 | { } | |
114 | ||
115 | ~View(); | |
116 | ||
117 | off_t | |
118 | start() const | |
119 | { return this->start_; } | |
120 | ||
121 | off_t | |
122 | size() const | |
123 | { return this->size_; } | |
124 | ||
e214a02b | 125 | const unsigned char* |
bae7f79e ILT |
126 | data() const |
127 | { return this->data_; } | |
128 | ||
129 | void | |
130 | lock(); | |
131 | ||
132 | void | |
133 | unlock(); | |
134 | ||
135 | bool | |
136 | is_locked(); | |
137 | ||
138 | private: | |
139 | View(const View&); | |
140 | View& operator=(const View&); | |
141 | ||
142 | off_t start_; | |
143 | off_t size_; | |
e214a02b | 144 | const unsigned char* data_; |
bae7f79e ILT |
145 | int lock_count_; |
146 | }; | |
147 | ||
148 | friend class File_view; | |
149 | ||
ead1e424 | 150 | // Find a view into the file. |
bae7f79e ILT |
151 | View* |
152 | find_view(off_t start, off_t size); | |
153 | ||
ead1e424 | 154 | // Read data from the file into a buffer. |
bae7f79e ILT |
155 | off_t |
156 | do_read(off_t start, off_t size, void* p, off_t* pbytes); | |
157 | ||
ead1e424 | 158 | // Find or make a view into the file. |
bae7f79e ILT |
159 | View* |
160 | find_or_make_view(off_t start, off_t size, off_t* pbytes); | |
161 | ||
ead1e424 | 162 | // Clear the file views. |
bae7f79e ILT |
163 | void |
164 | clear_views(bool); | |
165 | ||
ead1e424 ILT |
166 | // The size of a file page for buffering data. |
167 | static const off_t page_size = 8192; | |
168 | ||
169 | // Given a file offset, return the page offset. | |
170 | static off_t | |
171 | page_offset(off_t file_offset) | |
172 | { return file_offset & ~ (page_size - 1); } | |
173 | ||
174 | // Given a file size, return the size to read integral pages. | |
175 | static off_t | |
176 | pages(off_t file_size) | |
177 | { return (file_size + (page_size - 1)) & ~ (page_size - 1); } | |
178 | ||
179 | // The type of a mapping from page start to views. | |
180 | typedef std::map<off_t, View*> Views; | |
181 | ||
182 | // A simple list of Views. | |
183 | typedef std::list<View*> Saved_views; | |
184 | ||
185 | // File name. | |
bae7f79e | 186 | std::string name_; |
ead1e424 | 187 | // File descriptor. |
bae7f79e | 188 | int descriptor_; |
ead1e424 | 189 | // Number of locks on the file. |
bae7f79e | 190 | int lock_count_; |
ead1e424 ILT |
191 | // Buffered views into the file. |
192 | Views views_; | |
193 | // List of views which were locked but had to be removed from views_ | |
194 | // because they were not large enough. | |
195 | Saved_views saved_views_; | |
5a6f7e2d ILT |
196 | // Specified file contents. Used only for testing purposes. |
197 | const unsigned char* contents_; | |
198 | // Specified file size. Used only for testing purposes. | |
199 | off_t contents_size_; | |
bae7f79e ILT |
200 | }; |
201 | ||
202 | // A view of file data that persists even when the file is unlocked. | |
203 | // Callers should destroy these when no longer required. These are | |
204 | // obtained form File_read::get_lasting_view. They may only be | |
205 | // destroyed when the underlying File_read is locked. | |
206 | ||
207 | class File_view | |
208 | { | |
209 | public: | |
210 | // This may only be called when the underlying File_read is locked. | |
211 | ~File_view(); | |
212 | ||
213 | // Return a pointer to the data associated with this view. | |
214 | const unsigned char* | |
215 | data() const | |
216 | { return this->data_; } | |
217 | ||
218 | private: | |
219 | File_view(const File_view&); | |
220 | File_view& operator=(const File_view&); | |
221 | ||
222 | friend class File_read; | |
223 | ||
224 | // Callers have to get these via File_read::get_lasting_view. | |
225 | File_view(File_read& file, File_read::View* view, const unsigned char* data) | |
226 | : file_(file), view_(view), data_(data) | |
227 | { } | |
228 | ||
229 | File_read& file_; | |
230 | File_read::View* view_; | |
231 | const unsigned char* data_; | |
232 | }; | |
233 | ||
bae7f79e ILT |
234 | // All the information we hold for a single input file. This can be |
235 | // an object file, a shared library, or an archive. | |
236 | ||
237 | class Input_file | |
238 | { | |
239 | public: | |
5a6f7e2d ILT |
240 | Input_file(const Input_file_argument* input_argument) |
241 | : input_argument_(input_argument), file_() | |
bae7f79e ILT |
242 | { } |
243 | ||
5a6f7e2d ILT |
244 | // Create an input file with the contents already provided. This is |
245 | // only used for testing. With this path, don't call the open | |
246 | // method. | |
247 | Input_file(const char* name, const unsigned char* contents, off_t size); | |
248 | ||
249 | // Open the file. | |
bae7f79e ILT |
250 | void |
251 | open(const General_options&, const Dirsearch&); | |
252 | ||
253 | // Return the name given by the user. | |
254 | const char* | |
255 | name() const | |
5a6f7e2d | 256 | { return this->input_argument_->name(); } |
bae7f79e ILT |
257 | |
258 | // Return the file name. | |
259 | const std::string& | |
260 | filename() const | |
261 | { return this->file_.filename(); } | |
262 | ||
4973341a ILT |
263 | // Return the position dependent options. |
264 | const Position_dependent_options& | |
265 | options() const | |
266 | { return this->input_argument_->options(); } | |
267 | ||
268 | // Return the file. | |
bae7f79e ILT |
269 | File_read& |
270 | file() | |
271 | { return this->file_; } | |
272 | ||
273 | private: | |
ead1e424 ILT |
274 | Input_file(const Input_file&); |
275 | Input_file& operator=(const Input_file&); | |
276 | ||
5a6f7e2d | 277 | const Input_file_argument* input_argument_; |
bae7f79e ILT |
278 | File_read file_; |
279 | }; | |
280 | ||
281 | } // end namespace gold | |
282 | ||
283 | #endif // !defined(GOLD_FILEREAD_H) |