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1 | // fileread.h -- read files for gold -*- C++ -*- |
2 | ||
3 | // Classes used to read data from binary input files. | |
4 | ||
5 | #ifndef GOLD_FILEREAD_H | |
6 | #define GOLD_FILEREAD_H | |
7 | ||
bae7f79e | 8 | #include <list> |
ead1e424 ILT |
9 | #include <map> |
10 | #include <string> | |
bae7f79e ILT |
11 | |
12 | #include "options.h" | |
13 | ||
14 | namespace gold | |
15 | { | |
16 | ||
17 | class Dirsearch; | |
bae7f79e ILT |
18 | class File_view; |
19 | ||
20 | // File_read manages a file descriptor for a file we are reading. We | |
21 | // close file descriptors if we run out of them, so this class reopens | |
22 | // the file as needed. | |
23 | ||
24 | class File_read | |
25 | { | |
26 | public: | |
27 | File_read() | |
28 | : name_(), descriptor_(-1), lock_count_(0) | |
29 | { } | |
30 | ~File_read(); | |
31 | ||
32 | // Open a file. | |
33 | bool | |
34 | open(const std::string& name); | |
35 | ||
36 | // Return the file name. | |
37 | const std::string& | |
38 | filename() const | |
39 | { return this->name_; } | |
40 | ||
41 | // Return the file descriptor. | |
42 | int | |
43 | get_descriptor(); | |
44 | ||
45 | // Lock the file for access within a particular Task::run execution. | |
46 | // This means that the descriptor can not be closed. This routine | |
47 | // may only be called from the main thread. | |
48 | void | |
49 | lock(); | |
50 | ||
51 | // Unlock the descriptor, permitting it to be closed if necessary. | |
52 | void | |
53 | unlock(); | |
54 | ||
55 | // Test whether the object is locked. | |
56 | bool | |
57 | is_locked(); | |
58 | ||
59 | // Return a view into the file. The pointer will remain valid until | |
60 | // the File_read is unlocked. If PBYTES is NULL, it is an error if | |
61 | // we can not read enough data. Otherwise *PBYTES is set to the | |
62 | // number of bytes read. | |
63 | const unsigned char* | |
64 | get_view(off_t start, off_t size, off_t *pbytes = NULL); | |
65 | ||
66 | // Read data from the file into the buffer P. PBYTES is as in | |
67 | // get_view. | |
68 | void | |
69 | read(off_t start, off_t size, void* p, off_t *pbytes = NULL); | |
70 | ||
71 | // Return a lasting view into the file. This is allocated with new, | |
72 | // and the caller is responsible for deleting it when done. The | |
73 | // data associated with this view will remain valid until the view | |
74 | // is deleted. PBYTES is handled as with get_view. | |
75 | File_view* | |
76 | get_lasting_view(off_t start, off_t size, off_t *pbytes = NULL); | |
77 | ||
78 | private: | |
79 | // This class may not be copied. | |
80 | File_read(const File_read&); | |
81 | File_read& operator=(const File_read&); | |
82 | ||
83 | // A view into the file when not using mmap. | |
84 | class View | |
85 | { | |
86 | public: | |
87 | View(off_t start, off_t size, unsigned char* data) | |
88 | : start_(start), size_(size), data_(data), lock_count_(0) | |
89 | { } | |
90 | ||
91 | ~View(); | |
92 | ||
93 | off_t | |
94 | start() const | |
95 | { return this->start_; } | |
96 | ||
97 | off_t | |
98 | size() const | |
99 | { return this->size_; } | |
100 | ||
101 | unsigned char* | |
102 | data() const | |
103 | { return this->data_; } | |
104 | ||
105 | void | |
106 | lock(); | |
107 | ||
108 | void | |
109 | unlock(); | |
110 | ||
111 | bool | |
112 | is_locked(); | |
113 | ||
114 | private: | |
115 | View(const View&); | |
116 | View& operator=(const View&); | |
117 | ||
118 | off_t start_; | |
119 | off_t size_; | |
120 | unsigned char* data_; | |
121 | int lock_count_; | |
122 | }; | |
123 | ||
124 | friend class File_view; | |
125 | ||
ead1e424 | 126 | // Find a view into the file. |
bae7f79e ILT |
127 | View* |
128 | find_view(off_t start, off_t size); | |
129 | ||
ead1e424 | 130 | // Read data from the file into a buffer. |
bae7f79e ILT |
131 | off_t |
132 | do_read(off_t start, off_t size, void* p, off_t* pbytes); | |
133 | ||
ead1e424 | 134 | // Find or make a view into the file. |
bae7f79e ILT |
135 | View* |
136 | find_or_make_view(off_t start, off_t size, off_t* pbytes); | |
137 | ||
ead1e424 | 138 | // Clear the file views. |
bae7f79e ILT |
139 | void |
140 | clear_views(bool); | |
141 | ||
ead1e424 ILT |
142 | // The size of a file page for buffering data. |
143 | static const off_t page_size = 8192; | |
144 | ||
145 | // Given a file offset, return the page offset. | |
146 | static off_t | |
147 | page_offset(off_t file_offset) | |
148 | { return file_offset & ~ (page_size - 1); } | |
149 | ||
150 | // Given a file size, return the size to read integral pages. | |
151 | static off_t | |
152 | pages(off_t file_size) | |
153 | { return (file_size + (page_size - 1)) & ~ (page_size - 1); } | |
154 | ||
155 | // The type of a mapping from page start to views. | |
156 | typedef std::map<off_t, View*> Views; | |
157 | ||
158 | // A simple list of Views. | |
159 | typedef std::list<View*> Saved_views; | |
160 | ||
161 | // File name. | |
bae7f79e | 162 | std::string name_; |
ead1e424 | 163 | // File descriptor. |
bae7f79e | 164 | int descriptor_; |
ead1e424 | 165 | // Number of locks on the file. |
bae7f79e | 166 | int lock_count_; |
ead1e424 ILT |
167 | // Buffered views into the file. |
168 | Views views_; | |
169 | // List of views which were locked but had to be removed from views_ | |
170 | // because they were not large enough. | |
171 | Saved_views saved_views_; | |
bae7f79e ILT |
172 | }; |
173 | ||
174 | // A view of file data that persists even when the file is unlocked. | |
175 | // Callers should destroy these when no longer required. These are | |
176 | // obtained form File_read::get_lasting_view. They may only be | |
177 | // destroyed when the underlying File_read is locked. | |
178 | ||
179 | class File_view | |
180 | { | |
181 | public: | |
182 | // This may only be called when the underlying File_read is locked. | |
183 | ~File_view(); | |
184 | ||
185 | // Return a pointer to the data associated with this view. | |
186 | const unsigned char* | |
187 | data() const | |
188 | { return this->data_; } | |
189 | ||
190 | private: | |
191 | File_view(const File_view&); | |
192 | File_view& operator=(const File_view&); | |
193 | ||
194 | friend class File_read; | |
195 | ||
196 | // Callers have to get these via File_read::get_lasting_view. | |
197 | File_view(File_read& file, File_read::View* view, const unsigned char* data) | |
198 | : file_(file), view_(view), data_(data) | |
199 | { } | |
200 | ||
201 | File_read& file_; | |
202 | File_read::View* view_; | |
203 | const unsigned char* data_; | |
204 | }; | |
205 | ||
bae7f79e ILT |
206 | // All the information we hold for a single input file. This can be |
207 | // an object file, a shared library, or an archive. | |
208 | ||
209 | class Input_file | |
210 | { | |
211 | public: | |
ead1e424 | 212 | Input_file(const Input_file_argument& input_argument) |
bae7f79e ILT |
213 | : input_argument_(input_argument) |
214 | { } | |
215 | ||
216 | void | |
217 | open(const General_options&, const Dirsearch&); | |
218 | ||
219 | // Return the name given by the user. | |
220 | const char* | |
221 | name() const | |
222 | { return this->input_argument_.name(); } | |
223 | ||
224 | // Return the file name. | |
225 | const std::string& | |
226 | filename() const | |
227 | { return this->file_.filename(); } | |
228 | ||
229 | File_read& | |
230 | file() | |
231 | { return this->file_; } | |
232 | ||
233 | private: | |
ead1e424 ILT |
234 | Input_file(const Input_file&); |
235 | Input_file& operator=(const Input_file&); | |
236 | ||
237 | const Input_file_argument& input_argument_; | |
bae7f79e ILT |
238 | File_read file_; |
239 | }; | |
240 | ||
241 | } // end namespace gold | |
242 | ||
243 | #endif // !defined(GOLD_FILEREAD_H) |