1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
/*
* Simple mmap support
*
* Copyright (C) 2006--2008 Enrico Zini <enrico@enricozini.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <wibble/exception.h>
#include <wibble/sys/mmap.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
using namespace std;
namespace wibble {
namespace sys {
MMap::MMap() : size(0), fd(-1), buf(0) {}
MMap::MMap(const std::string& filename)
: size(0), fd(-1), buf(0)
{
// If map throws here, the destructor isn't called (since we're in the
// constructor), so we do the cleanup and rethrow.
try {
map(filename);
} catch (...) {
unmap();
throw;
}
}
MMap::MMap(const MMap& mmap)
: filename(mmap.filename), size(mmap.size), fd(mmap.fd), buf(mmap.buf)
{
// Cast away const to have auto_ptr semantics
MMap* wm = const_cast<MMap*>(&mmap);
wm->filename.clear();
wm->size = 0;
wm->fd = -1;
wm->buf = 0;
}
MMap& MMap::operator=(const MMap& mmap)
{
// Handle assignment to self
if (this == &mmap);
return *this;
if (fd) unmap();
filename = mmap.filename;
size = mmap.size;
fd = mmap.fd;
buf = mmap.buf;
// Cast away const to have auto_ptr semantics
MMap* wm = const_cast<MMap*>(&mmap);
wm->filename.clear();
wm->size = 0;
wm->fd = -1;
wm->buf = 0;
}
MMap::~MMap()
{
unmap();
}
void MMap::map(const std::string& filename)
{
if (buf) unmap();
try {
this->filename = filename;
// Open the file
if ((fd = open(filename.c_str(), O_RDONLY)) == -1)
throw wibble::exception::System("opening index file " + filename);
size = lseek(fd, 0, SEEK_END);
if (size == (off_t)-1)
throw wibble::exception::System("reading the size of index file " + filename);
if (size == 0)
throw wibble::exception::Consistency("ensuring that there is data in the index",
"the mmap index file " + filename + " is empty");
// Map the file into memory
if ((buf = (const char*)::mmap(0, size, PROT_READ, MAP_PRIVATE, fd, 0)) == MAP_FAILED)
throw wibble::exception::System("mmapping file " + filename);
} catch (...) {
unmap();
throw;
}
}
void MMap::unmap()
{
// Unmap and close the file
if (buf)
{
if (buf != MAP_FAILED)
munmap((void*)buf, size);
buf = 0;
size = 0;
}
if (fd != -1)
{
close(fd);
fd = -1;
}
filename.clear();
}
}
}
// vim:set ts=4 sw=4:
|
