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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.34 by root, Thu Aug 18 16:32:10 2005 UTC vs.
Revision 1.40 by root, Tue Aug 30 15:45:10 2005 UTC

63use base 'Exporter'; 63use base 'Exporter';
64 64
65use Fcntl (); 65use Fcntl ();
66 66
67BEGIN { 67BEGIN {
68 $VERSION = 1.5; 68 $VERSION = 1.6;
69 69
70 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink 70 @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
71 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
71 aio_rmdir aio_symlink aio_fsync aio_fdatasync aio_readahead); 72 aio_fsync aio_fdatasync aio_readahead);
72 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); 73 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel
74 max_outstanding nreqs);
73 75
74 require XSLoader; 76 require XSLoader;
75 XSLoader::load IO::AIO, $VERSION; 77 XSLoader::load IO::AIO, $VERSION;
76} 78}
77 79
103environment, d) use Glib::filename_from_unicode on unicode filenames or e) 105environment, d) use Glib::filename_from_unicode on unicode filenames or e)
104use something else. 106use something else.
105 107
106=over 4 108=over 4
107 109
108=item aio_open $pathname, $flags, $mode, $callback 110=item aio_open $pathname, $flags, $mode, $callback->($fh)
109 111
110Asynchronously open or create a file and call the callback with a newly 112Asynchronously open or create a file and call the callback with a newly
111created filehandle for the file. 113created filehandle for the file.
112 114
113The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 115The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
130 } else { 132 } else {
131 die "open failed: $!\n"; 133 die "open failed: $!\n";
132 } 134 }
133 }; 135 };
134 136
135=item aio_close $fh, $callback 137=item aio_close $fh, $callback->($status)
136 138
137Asynchronously close a file and call the callback with the result 139Asynchronously close a file and call the callback with the result
138code. I<WARNING:> although accepted, you should not pass in a perl 140code. I<WARNING:> although accepted, you should not pass in a perl
139filehandle here, as perl will likely close the file descriptor another 141filehandle here, as perl will likely close the file descriptor another
140time when the filehandle is destroyed. Normally, you can safely call perls 142time when the filehandle is destroyed. Normally, you can safely call perls
141C<close> or just let filehandles go out of scope. 143C<close> or just let filehandles go out of scope.
142 144
143This is supposed to be a bug in the API, so that might change. It's 145This is supposed to be a bug in the API, so that might change. It's
144therefore best to avoid this function. 146therefore best to avoid this function.
145 147
146=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback 148=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
147 149
148=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback 150=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
149 151
150Reads or writes C<length> bytes from the specified C<fh> and C<offset> 152Reads or writes C<length> bytes from the specified C<fh> and C<offset>
151into the scalar given by C<data> and offset C<dataoffset> and calls the 153into the scalar given by C<data> and offset C<dataoffset> and calls the
152callback without the actual number of bytes read (or -1 on error, just 154callback without the actual number of bytes read (or -1 on error, just
153like the syscall). 155like the syscall).
162 aio_read $fh, 7, 15, $buffer, 0, sub { 164 aio_read $fh, 7, 15, $buffer, 0, sub {
163 $_[0] > 0 or die "read error: $!"; 165 $_[0] > 0 or die "read error: $!";
164 print "read $_[0] bytes: <$buffer>\n"; 166 print "read $_[0] bytes: <$buffer>\n";
165 }; 167 };
166 168
169=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
170
171Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
172reading at byte offset C<$in_offset>, and starts writing at the current
173file offset of C<$out_fh>. Because of that, it is not safe to issue more
174than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
175other.
176
177This call tries to make use of a native C<sendfile> syscall to provide
178zero-copy operation. For this to work, C<$out_fh> should refer to a
179socket, and C<$in_fh> should refer to mmap'able file.
180
181If the native sendfile call fails or is not implemented, it will be
182emulated, so you can call C<aio_sendfile> on any type of filehandle
183regardless of the limitations of the operating system.
184
185Please note, however, that C<aio_sendfile> can read more bytes from
186C<$in_fh> than are written, and there is no way to find out how many
187bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
188provides the number of bytes written to C<$out_fh>. Only if the result
189value equals C<$length> one can assume that C<$length> bytes have been
190read.
191
167=item aio_readahead $fh,$offset,$length, $callback 192=item aio_readahead $fh,$offset,$length, $callback->($retval)
168 193
169C<aio_readahead> populates the page cache with data from a file so that 194C<aio_readahead> populates the page cache with data from a file so that
170subsequent reads from that file will not block on disk I/O. The C<$offset> 195subsequent reads from that file will not block on disk I/O. The C<$offset>
171argument specifies the starting point from which data is to be read and 196argument specifies the starting point from which data is to be read and
172C<$length> specifies the number of bytes to be read. I/O is performed in 197C<$length> specifies the number of bytes to be read. I/O is performed in
176file. The current file offset of the file is left unchanged. 201file. The current file offset of the file is left unchanged.
177 202
178If that syscall doesn't exist (likely if your OS isn't Linux) it will be 203If that syscall doesn't exist (likely if your OS isn't Linux) it will be
179emulated by simply reading the data, which would have a similar effect. 204emulated by simply reading the data, which would have a similar effect.
180 205
181=item aio_stat $fh_or_path, $callback 206=item aio_stat $fh_or_path, $callback->($status)
182 207
183=item aio_lstat $fh, $callback 208=item aio_lstat $fh, $callback->($status)
184 209
185Works like perl's C<stat> or C<lstat> in void context. The callback will 210Works like perl's C<stat> or C<lstat> in void context. The callback will
186be called after the stat and the results will be available using C<stat _> 211be called after the stat and the results will be available using C<stat _>
187or C<-s _> etc... 212or C<-s _> etc...
188 213
198 aio_stat "/etc/passwd", sub { 223 aio_stat "/etc/passwd", sub {
199 $_[0] and die "stat failed: $!"; 224 $_[0] and die "stat failed: $!";
200 print "size is ", -s _, "\n"; 225 print "size is ", -s _, "\n";
201 }; 226 };
202 227
203=item aio_unlink $pathname, $callback 228=item aio_unlink $pathname, $callback->($status)
204 229
205Asynchronously unlink (delete) a file and call the callback with the 230Asynchronously unlink (delete) a file and call the callback with the
206result code. 231result code.
207 232
208=item aio_rmdir $pathname, $callback 233=item aio_rmdir $pathname, $callback->($status)
209 234
210Asynchronously rmdir (delete) a directory and call the callback with the 235Asynchronously rmdir (delete) a directory and call the callback with the
211result code. 236result code.
212 237
238=item aio_readdir $pathname $callback->($entries)
239
240Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
241directory (i.e. opendir + readdir + closedir). The entries will not be
242sorted, and will B<NOT> include the C<.> and C<..> entries.
243
244The callback a single argument which is either C<undef> or an array-ref
245with the filenames.
246
247=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
248
249Scans a directory (similar to C<aio_readdir>) and tries to separate the
250entries of directory C<$path> into two sets of names, ones you can recurse
251into (directories), and ones you cannot recurse into (everything else).
252
253C<aio_scandir> is a composite request that consists of many
254aio-primitives. C<$maxreq> specifies the maximum number of outstanding
255aio requests that this function generates. If it is C<< <= 0 >>, then a
256suitable default will be chosen (currently 8).
257
258On error, the callback is called without arguments, otherwise it receives
259two array-refs with path-relative entry names.
260
261Example:
262
263 aio_scandir $dir, 0, sub {
264 my ($dirs, $nondirs) = @_;
265 print "real directories: @$dirs\n";
266 print "everything else: @$nondirs\n";
267 };
268
269Implementation notes.
270
271The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
272
273After reading the directory, the modification time, size etc. of the
274directory before and after the readdir is checked, and if they match, the
275link count will be used to decide how many entries are directories (if
276>= 2). Otherwise, no knowledge of the number of subdirectories will be
277assumed.
278
279Then entires will be sorted into likely directories (everything without a
280non-initial dot) and likely non-directories (everything else). Then every
281entry + C</.> will be C<stat>'ed, likely directories first. This is often
282faster because filesystems might detect the type of the entry without
283reading the inode data (e.g. ext2s filetype feature). If that succeeds,
284it assumes that the entry is a directory or a symlink to directory (which
285will be checked seperately).
286
287If the known number of directories has been reached, the rest of the
288entries is assumed to be non-directories.
289
290=cut
291
292sub aio_scandir($$$) {
293 my ($path, $maxreq, $cb) = @_;
294
295 $maxreq = 8 if $maxreq <= 0;
296
297 # stat once
298 aio_stat $path, sub {
299 $cb->() if $_[0];
300 my $hash1 = join ":", (stat _)[0,1,3,7,9];
301
302 # read the directory entries
303 aio_readdir $path, sub {
304 my $entries = shift
305 or return $cb->();
306
307 # stat the dir another time
308 aio_stat $path, sub {
309 my $hash2 = join ":", (stat _)[0,1,3,7,9];
310
311 my $ndirs;
312
313 # take the slow route if anything looks fishy
314 if ($hash1 ne $hash2) {
315 $ndirs = -1;
316 } else {
317 # if nlink == 2, we are finished
318 # on non-posix-fs's, we rely on nlink < 2
319 $ndirs = (stat _)[3] - 2
320 or $cb->([], $entries);
321 }
322
323 # sort into likely dirs and likely nondirs
324 # dirs == files without ".", short entries first
325 $entries = [map $_->[0],
326 sort { $b->[1] cmp $a->[1] }
327 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
328 @$entries];
329
330 my (@dirs, @nondirs);
331
332 my ($statcb, $schedcb);
333 my $nreq = 0;
334
335 $schedcb = sub {
336 if (@$entries) {
337 if ($nreq < $maxreq) {
338 my $ent = pop @$entries;
339 $nreq++;
340 aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
341 }
342 } elsif (!$nreq) {
343 # finished
344 undef $statcb;
345 undef $schedcb;
346 $cb->(\@dirs, \@nondirs);
347 undef $cb;
348 }
349 };
350 $statcb = sub {
351 my ($status, $entry) = @_;
352
353 if ($status < 0) {
354 $nreq--;
355 push @nondirs, $entry;
356 &$schedcb;
357 } else {
358 # need to check for real directory
359 aio_lstat "$path/$entry", sub {
360 $nreq--;
361
362 if (-d _) {
363 push @dirs, $entry;
364
365 if (!--$ndirs) {
366 push @nondirs, @$entries;
367 $entries = [];
368 }
369 } else {
370 push @nondirs, $entry;
371 }
372
373 &$schedcb;
374 }
375 }
376 };
377
378 &$schedcb while @$entries && $nreq < $maxreq;
379 };
380 };
381 };
382}
383
213=item aio_fsync $fh, $callback 384=item aio_fsync $fh, $callback->($status)
214 385
215Asynchronously call fsync on the given filehandle and call the callback 386Asynchronously call fsync on the given filehandle and call the callback
216with the fsync result code. 387with the fsync result code.
217 388
218=item aio_fdatasync $fh, $callback 389=item aio_fdatasync $fh, $callback->($status)
219 390
220Asynchronously call fdatasync on the given filehandle and call the 391Asynchronously call fdatasync on the given filehandle and call the
221callback with the fdatasync result code. 392callback with the fdatasync result code.
222 393
223If this call isn't available because your OS lacks it or it couldn't be 394If this call isn't available because your OS lacks it or it couldn't be

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