1 // fileread.h -- read files for gold -*- C++ -*-
3 // Copyright 2006, 2007 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
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.
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.
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.
23 // Classes used to read data from binary input files.
25 #ifndef GOLD_FILEREAD_H
26 #define GOLD_FILEREAD_H
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.
48 : name_(), descriptor_(-1), lock_count_(0), views_(),
49 saved_views_(), contents_(NULL), contents_size_(0)
56 open(const std::string& name);
58 // Pretend to open the file, but provide the file contents. No
59 // actual file system activity will occur. This is used for
62 open(const std::string& name, const unsigned char* contents, off_t size);
64 // Return the file name.
67 { return this->name_; }
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.
75 // Unlock the descriptor, permitting it to be closed if necessary.
79 // Test whether the object is locked.
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.
88 get_view(off_t start, off_t size, off_t* pbytes = NULL);
90 // Read data from the file into the buffer P. PBYTES is as in
93 read(off_t start, off_t size, void* p, off_t* pbytes = NULL);
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.
100 get_lasting_view(off_t start, off_t size, off_t *pbytes = NULL);
103 // This class may not be copied.
104 File_read(const File_read&);
105 File_read& operator=(const File_read&);
107 // A view into the file when not using mmap.
111 View(off_t start, off_t size, const unsigned char* data)
112 : start_(start), size_(size), data_(data), lock_count_(0)
119 { return this->start_; }
123 { return this->size_; }
127 { return this->data_; }
140 View& operator=(const View&);
144 const unsigned char* data_;
148 friend class File_view;
150 // Find a view into the file.
152 find_view(off_t start, off_t size);
154 // Read data from the file into a buffer.
156 do_read(off_t start, off_t size, void* p, off_t* pbytes);
158 // Find or make a view into the file.
160 find_or_make_view(off_t start, off_t size, off_t* pbytes);
162 // Clear the file views.
166 // The size of a file page for buffering data.
167 static const off_t page_size = 8192;
169 // Given a file offset, return the page offset.
171 page_offset(off_t file_offset)
172 { return file_offset & ~ (page_size - 1); }
174 // Given a file size, return the size to read integral pages.
176 pages(off_t file_size)
177 { return (file_size + (page_size - 1)) & ~ (page_size - 1); }
179 // The type of a mapping from page start to views.
180 typedef std::map<off_t, View*> Views;
182 // A simple list of Views.
183 typedef std::list<View*> Saved_views;
189 // Number of locks on the file.
191 // Buffered views into the file.
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_;
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_;
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.
210 // This may only be called when the underlying File_read is locked.
213 // Return a pointer to the data associated with this view.
216 { return this->data_; }
219 File_view(const File_view&);
220 File_view& operator=(const File_view&);
222 friend class File_read;
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)
230 File_read::View* view_;
231 const unsigned char* data_;
234 // All the information we hold for a single input file. This can be
235 // an object file, a shared library, or an archive.
240 Input_file(const Input_file_argument* input_argument)
241 : input_argument_(input_argument), file_()
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
247 Input_file(const char* name, const unsigned char* contents, off_t size);
251 open(const General_options&, const Dirsearch&);
253 // Return the name given by the user.
256 { return this->input_argument_->name(); }
258 // Return the file name.
261 { return this->file_.filename(); }
263 // Return the position dependent options.
264 const Position_dependent_options&
266 { return this->input_argument_->options(); }
271 { return this->file_; }
274 Input_file(const Input_file&);
275 Input_file& operator=(const Input_file&);
277 const Input_file_argument* input_argument_;
281 } // end namespace gold
283 #endif // !defined(GOLD_FILEREAD_H)