/[fuse_dbi]/trunk/fuse_dbi.pl
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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Contents of /trunk/fuse_dbi.pl

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Revision 7 - (show annotations)
Sat Aug 7 14:48:23 2004 UTC (17 years, 2 months ago) by dpavlin
File MIME type: text/plain
File size: 6014 byte(s)
make updates really work

1 #!/usr/bin/perl
2
3 use POSIX qw(ENOENT EISDIR EINVAL ENOSYS O_RDWR);
4 use Fuse;
5
6 use DBI;
7 use strict;
8
9 my $sql_filenames = q{
10 select
11 oid as id,
12 namespace||'/'||name||' ['||oid||']' as filename,
13 length(template) as size,
14 iseditable as writable
15 from template ;
16 };
17
18 my $sql_read = q{
19 select template
20 from template
21 where oid = ?;
22 };
23
24 my $sql_update = q{
25 update template
26 set template = ?
27 where oid = ?;
28 };
29
30
31 my $connect = "DBI:Pg:dbname=webgui";
32
33 my $dbh = DBI->connect($connect,"","", { AutoCommit => 0 }) || die $DBI::errstr;
34
35 print "start transaction\n";
36 #$dbh->begin_work || die $dbh->errstr;
37
38 my $sth_filenames = $dbh->prepare($sql_filenames) || die $dbh->errstr();
39 $sth_filenames->execute() || die $sth_filenames->errstr();
40
41 my $sth_read = $dbh->prepare($sql_read) || die $dbh->errstr();
42 my $sth_update = $dbh->prepare($sql_update) || die $dbh->errstr();
43
44 my $ctime_start = time();
45
46 my (%files) = (
47 '.' => {
48 type => 0040,
49 mode => 0755,
50 },
51 # a => {
52 # cont => "File 'a'.\n",
53 # type => 0100,
54 # ctime => time()-2000
55 # },
56 );
57
58 my %dirs;
59
60 while (my $row = $sth_filenames->fetchrow_hashref() ) {
61 $files{$row->{'filename'}} = {
62 size => $row->{'size'},
63 mode => $row->{'writable'} ? 0644 : 0444,
64 id => $row->{'id'} || 99,
65 };
66
67 my $d;
68 foreach (split(m!/!, $row->{'filename'})) {
69 # first, entry is assumed to be file
70 if ($d) {
71 $files{$d} = {
72 size => $dirs{$d}++,
73 mode => 0755,
74 type => 0040
75 };
76 $files{$d.'/.'} = {
77 mode => 0755,
78 type => 0040
79 };
80 $files{$d.'/..'} = {
81 mode => 0755,
82 type => 0040
83 };
84 }
85 $d .= "/" if ($d);
86 $d .= "$_";
87 }
88 }
89
90 print "found ",scalar(keys %files)-scalar(keys %dirs)," files, ",scalar(keys %dirs), " dirs\n";
91
92 sub filename_fixup {
93 my ($file) = shift;
94 $file =~ s,^/,,;
95 $file = '.' unless length($file);
96 return $file;
97 }
98
99 sub e_getattr {
100 my ($file) = filename_fixup(shift);
101 $file =~ s,^/,,;
102 $file = '.' unless length($file);
103 return -ENOENT() unless exists($files{$file});
104 my ($size) = $files{$file}{size} || 1;
105 my ($dev, $ino, $rdev, $blocks, $gid, $uid, $nlink, $blksize) = (0,0,0,1,0,0,1,1024);
106 my ($atime, $ctime, $mtime);
107 $atime = $ctime = $mtime = $files{$file}{ctime} || $ctime_start;
108
109 my ($modes) = (($files{$file}{type} || 0100)<<9) + $files{$file}{mode};
110
111 # 2 possible types of return values:
112 #return -ENOENT(); # or any other error you care to
113 #print(join(",",($dev,$ino,$modes,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,$blksize,$blocks)),"\n");
114 return ($dev,$ino,$modes,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,$blksize,$blocks);
115 }
116
117 sub e_getdir {
118 my ($dirname) = shift;
119 $dirname =~ s!^/!!;
120 # return as many text filenames as you like, followed by the retval.
121 print((scalar keys %files)." files total\n");
122 my %out;
123 foreach (keys %files) {
124 my $f = $_;
125 $f =~ s/^\E$dirname\Q//;
126 $f =~ s/^\///;
127 if ($dirname) {
128 $out{$f}++ if (/^\E$dirname\Q/ && $f =~ /^[^\/]+$/);
129 } else {
130 $out{$f}++ if ($f =~ /^[^\/]+$/);
131 }
132 }
133 if (! %out) {
134 $out{'no files? bug?'}++;
135 }
136 print scalar keys %out," files found for '$dirname': ",keys %out,"\n";
137 return (keys %out),0;
138 }
139
140 sub e_open {
141 # VFS sanity check; it keeps all the necessary state, not much to do here.
142 my $file = filename_fixup(shift);
143 my $flags = shift;
144
145 return -ENOENT() unless exists($files{$file});
146 return -EISDIR() unless exists($files{$file}{id});
147
148 if (!exists($files{$file}{cont})) {
149 $sth_read->execute($files{$file}{id}) || die $sth_read->errstr;
150 $files{$file}{cont} = $sth_read->fetchrow_array;
151 print "file '$file' content read in cache\n";
152 }
153 print "open '$file' ",length($files{$file}{cont})," bytes\n";
154 return 0;
155 }
156
157 sub e_read {
158 # return an error numeric, or binary/text string.
159 # (note: 0 means EOF, "0" will give a byte (ascii "0")
160 # to the reading program)
161 my ($file) = filename_fixup(shift);
162 my ($buf,$off) = @_;
163
164 return -ENOENT() unless exists($files{$file});
165
166 my $len = length($files{$file}{cont});
167
168 print "read '$file' [$len bytes] offset $off length $buf\n";
169
170 return -EINVAL() if ($off > $len);
171 return 0 if ($off == $len);
172
173 $buf = $len-$off if ($off+$buf > $len);
174
175 return substr($files{$file}{cont},$off,$buf);
176 }
177
178 sub clear_cont {
179 print "transaction rollback\n";
180 $dbh->rollback || die $dbh->errstr;
181 print "invalidate all cached content\n";
182 foreach my $f (keys %files) {
183 delete $files{$f}{cont};
184 }
185 print "begin new transaction\n";
186 $dbh->begin_work || die $dbh->errstr;
187 }
188
189
190 sub update_db {
191 my $file = shift || die;
192
193 if (!$sth_update->execute($files{$file}{cont},$files{$file}{id})) {
194 print "update problem: ",$sth_update->errstr;
195 clear_cont;
196 return 0;
197 } else {
198 if (! $dbh->commit) {
199 print "ERROR: commit problem: ",$sth_update->errstr;
200 clear_cont;
201 return 0;
202 }
203 print "updated '$file' [",$files{$file}{id},"]\n";
204 }
205 return 1;
206 }
207
208 sub e_write {
209 my $file = filename_fixup(shift);
210 my ($buf,$off) = @_;
211
212 return -ENOENT() unless exists($files{$file});
213
214 my $len = length($files{$file}{cont});
215
216 print "write '$file' [$len bytes] offset $off length $buf\n";
217
218 $files{$file}{cont} =
219 substr($files{$file}{cont},0,$off) .
220 $buf .
221 substr($files{$file}{cont},$off+length($buf));
222
223 if (! update_db($file)) {
224 return -ENOSYS();
225 } else {
226 return length($buf);
227 }
228 }
229
230 sub e_truncate {
231 my $file = filename_fixup(shift);
232 my $size = shift;
233
234 $files{$file}{cont} = substr($files{$file}{cont},0,$size);
235 return 0
236 };
237
238
239 sub e_utime {
240 my ($atime,$mtime,$file) = @_;
241 $file = filename_fixup($file);
242
243 return -ENOENT() unless exists($files{$file});
244
245 $files{$file}{time} = $mtime;
246 return 0;
247 }
248
249 sub e_statfs { return 255, 1, 1, 1, 1, 2 }
250
251 # If you run the script directly, it will run fusermount, which will in turn
252 # re-run this script. Hence the funky semantics.
253 my ($mountpoint) = "";
254 $mountpoint = shift(@ARGV) if @ARGV;
255 Fuse::main(
256 mountpoint=>$mountpoint,
257 getattr=>\&e_getattr,
258 getdir=>\&e_getdir,
259 open=>\&e_open,
260 statfs=>\&e_statfs,
261 read=>\&e_read,
262 write=>\&e_write,
263 utime=>\&e_utime,
264 truncate=>\&e_truncate,
265 debug=>0,
266 );

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