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), size_(0), lock_count_(0), views_(),
49 saved_views_(), contents_(NULL)
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 the size of the file.
86 { return this->size_; }
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. The CACHE parameter is a hint as to whether it will be
92 // useful to cache this data for later accesses--i.e., later calls
93 // to get_view, read, or get_lasting_view which retrieve the same
96 get_view(off_t start, off_t size, bool cache);
98 // Read data from the file into the buffer P starting at file offset
99 // START for SIZE bytes.
101 read(off_t start, off_t size, void* p);
103 // Return a lasting view into the file starting at file offset START
104 // for SIZE bytes. This is allocated with new, and the caller is
105 // responsible for deleting it when done. The data associated with
106 // this view will remain valid until the view is deleted. It is an
107 // error if we can not read enough data from the file. The CACHE
108 // parameter is as in get_view.
110 get_lasting_view(off_t start, off_t size, bool cache);
113 // This class may not be copied.
114 File_read(const File_read&);
115 File_read& operator=(const File_read&);
117 // A view into the file.
121 View(off_t start, off_t size, const unsigned char* data, bool cache,
123 : start_(start), size_(size), data_(data), lock_count_(0),
124 cache_(cache), mapped_(mapped)
131 { return this->start_; }
135 { return this->size_; }
139 { return this->data_; }
152 { this->cache_ = true; }
156 { return this->cache_; }
160 View& operator=(const View&);
164 const unsigned char* data_;
170 friend class File_view;
172 // Find a view into the file.
174 find_view(off_t start, off_t size);
176 // Read data from the file into a buffer.
178 do_read(off_t start, off_t size, void* p);
180 // Find or make a view into the file.
182 find_or_make_view(off_t start, off_t size, bool cache);
184 // Clear the file views.
188 // The size of a file page for buffering data.
189 static const off_t page_size = 8192;
191 // Given a file offset, return the page offset.
193 page_offset(off_t file_offset)
194 { return file_offset & ~ (page_size - 1); }
196 // Given a file size, return the size to read integral pages.
198 pages(off_t file_size)
199 { return (file_size + (page_size - 1)) & ~ (page_size - 1); }
201 // The type of a mapping from page start to views.
202 typedef std::map<off_t, View*> Views;
204 // A simple list of Views.
205 typedef std::list<View*> Saved_views;
213 // Number of locks on the file.
215 // Buffered views into the file.
217 // List of views which were locked but had to be removed from views_
218 // because they were not large enough.
219 Saved_views saved_views_;
220 // Specified file contents. Used only for testing purposes.
221 const unsigned char* contents_;
224 // A view of file data that persists even when the file is unlocked.
225 // Callers should destroy these when no longer required. These are
226 // obtained form File_read::get_lasting_view. They may only be
227 // destroyed when the underlying File_read is locked.
232 // This may only be called when the underlying File_read is locked.
235 // Return a pointer to the data associated with this view.
238 { return this->data_; }
241 File_view(const File_view&);
242 File_view& operator=(const File_view&);
244 friend class File_read;
246 // Callers have to get these via File_read::get_lasting_view.
247 File_view(File_read& file, File_read::View* view, const unsigned char* data)
248 : file_(file), view_(view), data_(data)
252 File_read::View* view_;
253 const unsigned char* data_;
256 // All the information we hold for a single input file. This can be
257 // an object file, a shared library, or an archive.
262 Input_file(const Input_file_argument* input_argument)
263 : input_argument_(input_argument), file_()
266 // Create an input file with the contents already provided. This is
267 // only used for testing. With this path, don't call the open
269 Input_file(const char* name, const unsigned char* contents, off_t size);
273 open(const General_options&, const Dirsearch&);
275 // Return the name given by the user.
278 { return this->input_argument_->name(); }
280 // Return the file name.
283 { return this->file_.filename(); }
285 // Return the position dependent options.
286 const Position_dependent_options&
288 { return this->input_argument_->options(); }
293 { return this->file_; }
296 Input_file(const Input_file&);
297 Input_file& operator=(const Input_file&);
299 const Input_file_argument* input_argument_;
303 } // end namespace gold
305 #endif // !defined(GOLD_FILEREAD_H)