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 when not using mmap.
121 View(off_t start
, off_t size
, const unsigned char* data
, bool cache
)
122 : start_(start
), size_(size
), data_(data
), lock_count_(0),
130 { return this->start_
; }
134 { return this->size_
; }
138 { return this->data_
; }
151 { this->cache_
= true; }
155 { return this->cache_
; }
159 View
& operator=(const View
&);
163 const unsigned char* data_
;
168 friend class File_view
;
170 // Find a view into the file.
172 find_view(off_t start
, off_t size
);
174 // Read data from the file into a buffer.
176 do_read(off_t start
, off_t size
, void* p
);
178 // Find or make a view into the file.
180 find_or_make_view(off_t start
, off_t size
, bool cache
);
182 // Clear the file views.
186 // The size of a file page for buffering data.
187 static const off_t page_size
= 8192;
189 // Given a file offset, return the page offset.
191 page_offset(off_t file_offset
)
192 { return file_offset
& ~ (page_size
- 1); }
194 // Given a file size, return the size to read integral pages.
196 pages(off_t file_size
)
197 { return (file_size
+ (page_size
- 1)) & ~ (page_size
- 1); }
199 // The type of a mapping from page start to views.
200 typedef std::map
<off_t
, View
*> Views
;
202 // A simple list of Views.
203 typedef std::list
<View
*> Saved_views
;
211 // Number of locks on the file.
213 // Buffered views into the file.
215 // List of views which were locked but had to be removed from views_
216 // because they were not large enough.
217 Saved_views saved_views_
;
218 // Specified file contents. Used only for testing purposes.
219 const unsigned char* contents_
;
222 // A view of file data that persists even when the file is unlocked.
223 // Callers should destroy these when no longer required. These are
224 // obtained form File_read::get_lasting_view. They may only be
225 // destroyed when the underlying File_read is locked.
230 // This may only be called when the underlying File_read is locked.
233 // Return a pointer to the data associated with this view.
236 { return this->data_
; }
239 File_view(const File_view
&);
240 File_view
& operator=(const File_view
&);
242 friend class File_read
;
244 // Callers have to get these via File_read::get_lasting_view.
245 File_view(File_read
& file
, File_read::View
* view
, const unsigned char* data
)
246 : file_(file
), view_(view
), data_(data
)
250 File_read::View
* view_
;
251 const unsigned char* data_
;
254 // All the information we hold for a single input file. This can be
255 // an object file, a shared library, or an archive.
260 Input_file(const Input_file_argument
* input_argument
)
261 : input_argument_(input_argument
), file_()
264 // Create an input file with the contents already provided. This is
265 // only used for testing. With this path, don't call the open
267 Input_file(const char* name
, const unsigned char* contents
, off_t size
);
271 open(const General_options
&, const Dirsearch
&);
273 // Return the name given by the user.
276 { return this->input_argument_
->name(); }
278 // Return the file name.
281 { return this->file_
.filename(); }
283 // Return the position dependent options.
284 const Position_dependent_options
&
286 { return this->input_argument_
->options(); }
291 { return this->file_
; }
294 Input_file(const Input_file
&);
295 Input_file
& operator=(const Input_file
&);
297 const Input_file_argument
* input_argument_
;
301 } // end namespace gold
303 #endif // !defined(GOLD_FILEREAD_H)