… | |
… | |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use IO::AIO; |
7 | use IO::AIO; |
8 | |
8 | |
9 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
9 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
10 | my $fh = shift |
10 | my $fh = shift |
11 | or die "/etc/passwd: $!"; |
11 | or die "/etc/passwd: $!"; |
12 | ... |
12 | ... |
13 | }; |
13 | }; |
14 | |
14 | |
… | |
… | |
26 | $req->cancel; # cancel request if still in queue |
26 | $req->cancel; # cancel request if still in queue |
27 | |
27 | |
28 | my $grp = aio_group sub { print "all stats done\n" }; |
28 | my $grp = aio_group sub { print "all stats done\n" }; |
29 | add $grp aio_stat "..." for ...; |
29 | add $grp aio_stat "..." for ...; |
30 | |
30 | |
31 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
|
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32 | use AnyEvent::AIO; |
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33 | |
|
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34 | # EV integration |
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35 | my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
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36 | |
|
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37 | # Event integration |
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38 | Event->io (fd => IO::AIO::poll_fileno, |
|
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39 | poll => 'r', |
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40 | cb => \&IO::AIO::poll_cb); |
|
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41 | |
|
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42 | # Glib/Gtk2 integration |
|
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43 | add_watch Glib::IO IO::AIO::poll_fileno, |
|
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44 | in => sub { IO::AIO::poll_cb; 1 }; |
|
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45 | |
|
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46 | # Tk integration |
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47 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
|
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48 | readable => \&IO::AIO::poll_cb); |
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49 | |
|
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50 | # Danga::Socket integration |
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51 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
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52 | \&IO::AIO::poll_cb); |
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53 | |
|
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54 | =head1 DESCRIPTION |
31 | =head1 DESCRIPTION |
55 | |
32 | |
56 | This module implements asynchronous I/O using whatever means your |
33 | This module implements asynchronous I/O using whatever means your |
57 | operating system supports. |
34 | operating system supports. It is implemented as an interface to C<libeio> |
|
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35 | (L<http://software.schmorp.de/pkg/libeio.html>). |
58 | |
36 | |
59 | Asynchronous means that operations that can normally block your program |
37 | Asynchronous means that operations that can normally block your program |
60 | (e.g. reading from disk) will be done asynchronously: the operation |
38 | (e.g. reading from disk) will be done asynchronously: the operation |
61 | will still block, but you can do something else in the meantime. This |
39 | will still block, but you can do something else in the meantime. This |
62 | is extremely useful for programs that need to stay interactive even |
40 | is extremely useful for programs that need to stay interactive even |
… | |
… | |
66 | on a RAID volume or over NFS when you do a number of stat operations |
44 | on a RAID volume or over NFS when you do a number of stat operations |
67 | concurrently. |
45 | concurrently. |
68 | |
46 | |
69 | While most of this works on all types of file descriptors (for |
47 | While most of this works on all types of file descriptors (for |
70 | example sockets), using these functions on file descriptors that |
48 | example sockets), using these functions on file descriptors that |
71 | support nonblocking operation (again, sockets, pipes etc.) is very |
49 | support nonblocking operation (again, sockets, pipes etc.) is |
72 | inefficient. Use an event loop for that (such as the L<Event|Event> |
50 | very inefficient. Use an event loop for that (such as the L<EV> |
73 | module): IO::AIO will naturally fit into such an event loop itself. |
51 | module): IO::AIO will naturally fit into such an event loop itself. |
74 | |
52 | |
75 | In this version, a number of threads are started that execute your |
53 | In this version, a number of threads are started that execute your |
76 | requests and signal their completion. You don't need thread support |
54 | requests and signal their completion. You don't need thread support |
77 | in perl, and the threads created by this module will not be visible |
55 | in perl, and the threads created by this module will not be visible |
… | |
… | |
87 | yourself, always call C<poll_cb> from within the same thread, or never |
65 | yourself, always call C<poll_cb> from within the same thread, or never |
88 | call C<poll_cb> (or other C<aio_> functions) recursively. |
66 | call C<poll_cb> (or other C<aio_> functions) recursively. |
89 | |
67 | |
90 | =head2 EXAMPLE |
68 | =head2 EXAMPLE |
91 | |
69 | |
92 | This is a simple example that uses the Event module and loads |
70 | This is a simple example that uses the EV module and loads |
93 | F</etc/passwd> asynchronously: |
71 | F</etc/passwd> asynchronously: |
94 | |
72 | |
95 | use Fcntl; |
73 | use Fcntl; |
96 | use Event; |
74 | use EV; |
97 | use IO::AIO; |
75 | use IO::AIO; |
98 | |
76 | |
99 | # register the IO::AIO callback with Event |
77 | # register the IO::AIO callback with EV |
100 | Event->io (fd => IO::AIO::poll_fileno, |
78 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
101 | poll => 'r', |
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102 | cb => \&IO::AIO::poll_cb); |
|
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103 | |
79 | |
104 | # queue the request to open /etc/passwd |
80 | # queue the request to open /etc/passwd |
105 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
81 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
106 | my $fh = shift |
82 | my $fh = shift |
107 | or die "error while opening: $!"; |
83 | or die "error while opening: $!"; |
108 | |
84 | |
109 | # stat'ing filehandles is generally non-blocking |
85 | # stat'ing filehandles is generally non-blocking |
110 | my $size = -s $fh; |
86 | my $size = -s $fh; |
… | |
… | |
119 | |
95 | |
120 | # file contents now in $contents |
96 | # file contents now in $contents |
121 | print $contents; |
97 | print $contents; |
122 | |
98 | |
123 | # exit event loop and program |
99 | # exit event loop and program |
124 | Event::unloop; |
100 | EV::unloop; |
125 | }; |
101 | }; |
126 | }; |
102 | }; |
127 | |
103 | |
128 | # possibly queue up other requests, or open GUI windows, |
104 | # possibly queue up other requests, or open GUI windows, |
129 | # check for sockets etc. etc. |
105 | # check for sockets etc. etc. |
130 | |
106 | |
131 | # process events as long as there are some: |
107 | # process events as long as there are some: |
132 | Event::loop; |
108 | EV::loop; |
133 | |
109 | |
134 | =head1 REQUEST ANATOMY AND LIFETIME |
110 | =head1 REQUEST ANATOMY AND LIFETIME |
135 | |
111 | |
136 | Every C<aio_*> function creates a request. which is a C data structure not |
112 | Every C<aio_*> function creates a request. which is a C data structure not |
137 | directly visible to Perl. |
113 | directly visible to Perl. |
… | |
… | |
187 | |
163 | |
188 | package IO::AIO; |
164 | package IO::AIO; |
189 | |
165 | |
190 | use Carp (); |
166 | use Carp (); |
191 | |
167 | |
192 | no warnings; |
168 | use common::sense; |
193 | use strict 'vars'; |
|
|
194 | |
169 | |
195 | use base 'Exporter'; |
170 | use base 'Exporter'; |
196 | |
171 | |
197 | BEGIN { |
172 | BEGIN { |
198 | our $VERSION = '3.02'; |
173 | our $VERSION = '4.0'; |
199 | |
174 | |
200 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close |
175 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close |
201 | aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir |
176 | aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx |
202 | aio_scandir aio_symlink aio_readlink aio_sync aio_fsync |
177 | aio_scandir aio_symlink aio_readlink aio_realpath aio_sync |
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178 | aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate |
203 | aio_fdatasync aio_pathsync aio_readahead |
179 | aio_pathsync aio_readahead |
204 | aio_rename aio_link aio_move aio_copy aio_group |
180 | aio_rename aio_link aio_move aio_copy aio_group |
205 | aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown |
181 | aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown |
206 | aio_chmod aio_utime aio_truncate); |
182 | aio_chmod aio_utime aio_truncate |
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183 | aio_msync aio_mtouch aio_mlock aio_mlockall |
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184 | aio_statvfs |
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185 | aio_wd); |
207 | |
186 | |
208 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
187 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
209 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
188 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
210 | min_parallel max_parallel max_idle |
189 | min_parallel max_parallel max_idle idle_timeout |
211 | nreqs nready npending nthreads |
190 | nreqs nready npending nthreads |
212 | max_poll_time max_poll_reqs); |
191 | max_poll_time max_poll_reqs |
|
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192 | sendfile fadvise madvise |
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193 | mmap munmap munlock munlockall); |
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194 | |
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195 | push @AIO_REQ, qw(aio_busy); # not exported |
213 | |
196 | |
214 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
197 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
215 | |
198 | |
216 | require XSLoader; |
199 | require XSLoader; |
217 | XSLoader::load ("IO::AIO", $VERSION); |
200 | XSLoader::load ("IO::AIO", $VERSION); |
218 | } |
201 | } |
219 | |
202 | |
220 | =head1 FUNCTIONS |
203 | =head1 FUNCTIONS |
221 | |
204 | |
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205 | =head2 QUICK OVERVIEW |
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206 | |
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207 | This section simply lists the prototypes of the most important functions |
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208 | for quick reference. See the following sections for function-by-function |
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209 | documentation. |
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210 | |
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211 | aio_wd $pathname, $callback->($wd) |
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212 | aio_open $pathname, $flags, $mode, $callback->($fh) |
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213 | aio_close $fh, $callback->($status) |
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214 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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215 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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216 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
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217 | aio_readahead $fh,$offset,$length, $callback->($retval) |
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218 | aio_stat $fh_or_path, $callback->($status) |
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219 | aio_lstat $fh, $callback->($status) |
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220 | aio_statvfs $fh_or_path, $callback->($statvfs) |
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221 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
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222 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
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223 | aio_truncate $fh_or_path, $offset, $callback->($status) |
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224 | aio_chmod $fh_or_path, $mode, $callback->($status) |
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225 | aio_unlink $pathname, $callback->($status) |
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226 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
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227 | aio_link $srcpath, $dstpath, $callback->($status) |
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228 | aio_symlink $srcpath, $dstpath, $callback->($status) |
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229 | aio_readlink $pathname, $callback->($link) |
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230 | aio_realpath $pathname, $callback->($link) |
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231 | aio_rename $srcpath, $dstpath, $callback->($status) |
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232 | aio_mkdir $pathname, $mode, $callback->($status) |
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233 | aio_rmdir $pathname, $callback->($status) |
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234 | aio_readdir $pathname, $callback->($entries) |
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235 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
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236 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
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237 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
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238 | aio_load $pathname, $data, $callback->($status) |
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239 | aio_copy $srcpath, $dstpath, $callback->($status) |
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240 | aio_move $srcpath, $dstpath, $callback->($status) |
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241 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
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242 | aio_rmtree $pathname, $callback->($status) |
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243 | aio_sync $callback->($status) |
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244 | aio_syncfs $fh, $callback->($status) |
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245 | aio_fsync $fh, $callback->($status) |
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246 | aio_fdatasync $fh, $callback->($status) |
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247 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
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248 | aio_pathsync $pathname, $callback->($status) |
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249 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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250 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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251 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
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252 | aio_mlockall $flags, $callback->($status) |
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253 | aio_group $callback->(...) |
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254 | aio_nop $callback->() |
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255 | |
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256 | $prev_pri = aioreq_pri [$pri] |
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257 | aioreq_nice $pri_adjust |
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258 | |
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259 | IO::AIO::poll_wait |
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260 | IO::AIO::poll_cb |
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261 | IO::AIO::poll |
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262 | IO::AIO::flush |
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263 | IO::AIO::max_poll_reqs $nreqs |
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264 | IO::AIO::max_poll_time $seconds |
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265 | IO::AIO::min_parallel $nthreads |
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266 | IO::AIO::max_parallel $nthreads |
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267 | IO::AIO::max_idle $nthreads |
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268 | IO::AIO::idle_timeout $seconds |
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269 | IO::AIO::max_outstanding $maxreqs |
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270 | IO::AIO::nreqs |
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271 | IO::AIO::nready |
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272 | IO::AIO::npending |
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273 | |
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274 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
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275 | IO::AIO::fadvise $fh, $offset, $len, $advice |
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276 | IO::AIO::madvise $scalar, $offset, $length, $advice |
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277 | IO::AIO::mprotect $scalar, $offset, $length, $protect |
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278 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
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279 | IO::AIO::munlockall |
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280 | |
222 | =head2 AIO REQUEST FUNCTIONS |
281 | =head2 AIO REQUEST FUNCTIONS |
223 | |
282 | |
224 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
283 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
225 | with the same name (sans C<aio_>). The arguments are similar or identical, |
284 | with the same name (sans C<aio_>). The arguments are similar or identical, |
226 | and they all accept an additional (and optional) C<$callback> argument |
285 | and they all accept an additional (and optional) C<$callback> argument |
227 | which must be a code reference. This code reference will get called with |
286 | which must be a code reference. This code reference will be called after |
228 | the syscall return code (e.g. most syscalls return C<-1> on error, unlike |
287 | the syscall has been executed in an asynchronous fashion. The results |
229 | perl, which usually delivers "false") as it's sole argument when the given |
288 | of the request will be passed as arguments to the callback (and, if an |
230 | syscall has been executed asynchronously. |
289 | error occured, in C<$!>) - for most requests the syscall return code (e.g. |
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290 | most syscalls return C<-1> on error, unlike perl, which usually delivers |
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291 | "false"). |
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292 | |
|
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293 | Some requests (such as C<aio_readdir>) pass the actual results and |
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294 | communicate failures by passing C<undef>. |
231 | |
295 | |
232 | All functions expecting a filehandle keep a copy of the filehandle |
296 | All functions expecting a filehandle keep a copy of the filehandle |
233 | internally until the request has finished. |
297 | internally until the request has finished. |
234 | |
298 | |
235 | All functions return request objects of type L<IO::AIO::REQ> that allow |
299 | All functions return request objects of type L<IO::AIO::REQ> that allow |
236 | further manipulation of those requests while they are in-flight. |
300 | further manipulation of those requests while they are in-flight. |
237 | |
301 | |
238 | The pathnames you pass to these routines I<must> be absolute and |
302 | The pathnames you pass to these routines I<should> be absolute. The |
239 | encoded as octets. The reason for the former is that at the time the |
303 | reason for this is that at the time the request is being executed, the |
240 | request is being executed, the current working directory could have |
304 | current working directory could have changed. Alternatively, you can |
241 | changed. Alternatively, you can make sure that you never change the |
305 | make sure that you never change the current working directory anywhere |
242 | current working directory anywhere in the program and then use relative |
306 | in the program and then use relative paths. You can also take advantage |
243 | paths. |
307 | of IO::AIOs working directory abstraction, that lets you specify paths |
|
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308 | relative to some previously-opened "working directory object" - see the |
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309 | description of the C<IO::AIO::WD> class later in this document. |
244 | |
310 | |
245 | To encode pathnames as octets, either make sure you either: a) always pass |
311 | To encode pathnames as octets, either make sure you either: a) always pass |
246 | in filenames you got from outside (command line, readdir etc.) without |
312 | in filenames you got from outside (command line, readdir etc.) without |
247 | tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode |
313 | tinkering, b) are in your native filesystem encoding, c) use the Encode |
248 | your pathnames to the locale (or other) encoding in effect in the user |
314 | module and encode your pathnames to the locale (or other) encoding in |
249 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
315 | effect in the user environment, d) use Glib::filename_from_unicode on |
250 | use something else to ensure your scalar has the correct contents. |
316 | unicode filenames or e) use something else to ensure your scalar has the |
|
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317 | correct contents. |
251 | |
318 | |
252 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
319 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
253 | handles correctly wether it is set or not. |
320 | handles correctly whether it is set or not. |
254 | |
321 | |
255 | =over 4 |
322 | =over 4 |
256 | |
323 | |
257 | =item $prev_pri = aioreq_pri [$pri] |
324 | =item $prev_pri = aioreq_pri [$pri] |
258 | |
325 | |
… | |
… | |
305 | by the umask in effect then the request is being executed, so better never |
372 | by the umask in effect then the request is being executed, so better never |
306 | change the umask. |
373 | change the umask. |
307 | |
374 | |
308 | Example: |
375 | Example: |
309 | |
376 | |
310 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
377 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
311 | if ($_[0]) { |
378 | if ($_[0]) { |
312 | print "open successful, fh is $_[0]\n"; |
379 | print "open successful, fh is $_[0]\n"; |
313 | ... |
380 | ... |
314 | } else { |
381 | } else { |
315 | die "open failed: $!\n"; |
382 | die "open failed: $!\n"; |
316 | } |
383 | } |
317 | }; |
384 | }; |
318 | |
385 | |
|
|
386 | In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>, |
|
|
387 | C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the |
|
|
388 | following POSIX and non-POSIX constants are available (missing ones on |
|
|
389 | your system are, as usual, C<0>): |
|
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390 | |
|
|
391 | C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, |
|
|
392 | C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, |
|
|
393 | C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. |
|
|
394 | |
319 | |
395 | |
320 | =item aio_close $fh, $callback->($status) |
396 | =item aio_close $fh, $callback->($status) |
321 | |
397 | |
322 | Asynchronously close a file and call the callback with the result |
398 | Asynchronously close a file and call the callback with the result |
323 | code. |
399 | code. |
… | |
… | |
336 | |
412 | |
337 | =item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
413 | =item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
338 | |
414 | |
339 | =item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
415 | =item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
340 | |
416 | |
341 | Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset> |
417 | Reads or writes C<$length> bytes from or to the specified C<$fh> and |
342 | into the scalar given by C<$data> and offset C<$dataoffset> and calls the |
418 | C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> |
343 | callback without the actual number of bytes read (or -1 on error, just |
419 | and calls the callback without the actual number of bytes read (or -1 on |
344 | like the syscall). |
420 | error, just like the syscall). |
|
|
421 | |
|
|
422 | C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to |
|
|
423 | offset plus the actual number of bytes read. |
345 | |
424 | |
346 | If C<$offset> is undefined, then the current file descriptor offset will |
425 | If C<$offset> is undefined, then the current file descriptor offset will |
347 | be used (and updated), otherwise the file descriptor offset will not be |
426 | be used (and updated), otherwise the file descriptor offset will not be |
348 | changed by these calls. |
427 | changed by these calls. |
349 | |
428 | |
350 | If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>. |
429 | If C<$length> is undefined in C<aio_write>, use the remaining length of |
|
|
430 | C<$data>. |
351 | |
431 | |
352 | If C<$dataoffset> is less than zero, it will be counted from the end of |
432 | If C<$dataoffset> is less than zero, it will be counted from the end of |
353 | C<$data>. |
433 | C<$data>. |
354 | |
434 | |
355 | The C<$data> scalar I<MUST NOT> be modified in any way while the request |
435 | The C<$data> scalar I<MUST NOT> be modified in any way while the request |
… | |
… | |
369 | |
449 | |
370 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
450 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
371 | reading at byte offset C<$in_offset>, and starts writing at the current |
451 | reading at byte offset C<$in_offset>, and starts writing at the current |
372 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
452 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
373 | than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each |
453 | than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each |
374 | other. |
454 | other. The same C<$in_fh> works fine though, as this function does not |
|
|
455 | move or use the file offset of C<$in_fh>. |
375 | |
456 | |
|
|
457 | Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than |
|
|
458 | are written, and there is no way to find out how many more bytes have been |
|
|
459 | read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the |
|
|
460 | number of bytes written to C<$out_fh>. Only if the result value equals |
|
|
461 | C<$length> one can assume that C<$length> bytes have been read. |
|
|
462 | |
|
|
463 | Unlike with other C<aio_> functions, it makes a lot of sense to use |
|
|
464 | C<aio_sendfile> on non-blocking sockets, as long as one end (typically |
|
|
465 | the C<$in_fh>) is a file - the file I/O will then be asynchronous, while |
|
|
466 | the socket I/O will be non-blocking. Note, however, that you can run |
|
|
467 | into a trap where C<aio_sendfile> reads some data with readahead, then |
|
|
468 | fails to write all data, and when the socket is ready the next time, the |
|
|
469 | data in the cache is already lost, forcing C<aio_sendfile> to again hit |
|
|
470 | the disk. Explicit C<aio_read> + C<aio_write> let's you better control |
|
|
471 | resource usage. |
|
|
472 | |
376 | This call tries to make use of a native C<sendfile> syscall to provide |
473 | This call tries to make use of a native C<sendfile>-like syscall to |
377 | zero-copy operation. For this to work, C<$out_fh> should refer to a |
474 | provide zero-copy operation. For this to work, C<$out_fh> should refer to |
378 | socket, and C<$in_fh> should refer to mmap'able file. |
475 | a socket, and C<$in_fh> should refer to an mmap'able file. |
379 | |
476 | |
380 | If the native sendfile call fails or is not implemented, it will be |
477 | If a native sendfile cannot be found or it fails with C<ENOSYS>, |
381 | emulated, so you can call C<aio_sendfile> on any type of filehandle |
478 | C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or |
|
|
479 | C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any |
382 | regardless of the limitations of the operating system. |
480 | type of filehandle regardless of the limitations of the operating system. |
383 | |
481 | |
384 | Please note, however, that C<aio_sendfile> can read more bytes from |
482 | As native sendfile syscalls (as practically any non-POSIX interface hacked |
385 | C<$in_fh> than are written, and there is no way to find out how many |
483 | together in a hurry to improve benchmark numbers) tend to be rather buggy |
386 | bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only |
484 | on many systems, this implementation tries to work around some known bugs |
387 | provides the number of bytes written to C<$out_fh>. Only if the result |
485 | in Linux and FreeBSD kernels (probably others, too), but that might fail, |
388 | value equals C<$length> one can assume that C<$length> bytes have been |
486 | so you really really should check the return value of C<aio_sendfile> - |
389 | read. |
487 | fewre bytes than expected might have been transferred. |
390 | |
488 | |
391 | |
489 | |
392 | =item aio_readahead $fh,$offset,$length, $callback->($retval) |
490 | =item aio_readahead $fh,$offset,$length, $callback->($retval) |
393 | |
491 | |
394 | C<aio_readahead> populates the page cache with data from a file so that |
492 | C<aio_readahead> populates the page cache with data from a file so that |
… | |
… | |
417 | |
515 | |
418 | Currently, the stats are always 64-bit-stats, i.e. instead of returning an |
516 | Currently, the stats are always 64-bit-stats, i.e. instead of returning an |
419 | error when stat'ing a large file, the results will be silently truncated |
517 | error when stat'ing a large file, the results will be silently truncated |
420 | unless perl itself is compiled with large file support. |
518 | unless perl itself is compiled with large file support. |
421 | |
519 | |
|
|
520 | To help interpret the mode and dev/rdev stat values, IO::AIO offers the |
|
|
521 | following constants and functions (if not implemented, the constants will |
|
|
522 | be C<0> and the functions will either C<croak> or fall back on traditional |
|
|
523 | behaviour). |
|
|
524 | |
|
|
525 | C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, |
|
|
526 | C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>, |
|
|
527 | C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>. |
|
|
528 | |
422 | Example: Print the length of F</etc/passwd>: |
529 | Example: Print the length of F</etc/passwd>: |
423 | |
530 | |
424 | aio_stat "/etc/passwd", sub { |
531 | aio_stat "/etc/passwd", sub { |
425 | $_[0] and die "stat failed: $!"; |
532 | $_[0] and die "stat failed: $!"; |
426 | print "size is ", -s _, "\n"; |
533 | print "size is ", -s _, "\n"; |
427 | }; |
534 | }; |
428 | |
535 | |
429 | |
536 | |
|
|
537 | =item aio_statvfs $fh_or_path, $callback->($statvfs) |
|
|
538 | |
|
|
539 | Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on |
|
|
540 | whether a file handle or path was passed. |
|
|
541 | |
|
|
542 | On success, the callback is passed a hash reference with the following |
|
|
543 | members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>, |
|
|
544 | C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef> |
|
|
545 | is passed. |
|
|
546 | |
|
|
547 | The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and |
|
|
548 | C<ST_NOSUID>. |
|
|
549 | |
|
|
550 | The following non-POSIX IO::AIO::ST_* flag masks are defined to |
|
|
551 | their correct value when available, or to C<0> on systems that do |
|
|
552 | not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>, |
|
|
553 | C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>, |
|
|
554 | C<ST_NODIRATIME> and C<ST_RELATIME>. |
|
|
555 | |
|
|
556 | Example: stat C</wd> and dump out the data if successful. |
|
|
557 | |
|
|
558 | aio_statvfs "/wd", sub { |
|
|
559 | my $f = $_[0] |
|
|
560 | or die "statvfs: $!"; |
|
|
561 | |
|
|
562 | use Data::Dumper; |
|
|
563 | say Dumper $f; |
|
|
564 | }; |
|
|
565 | |
|
|
566 | # result: |
|
|
567 | { |
|
|
568 | bsize => 1024, |
|
|
569 | bfree => 4333064312, |
|
|
570 | blocks => 10253828096, |
|
|
571 | files => 2050765568, |
|
|
572 | flag => 4096, |
|
|
573 | favail => 2042092649, |
|
|
574 | bavail => 4333064312, |
|
|
575 | ffree => 2042092649, |
|
|
576 | namemax => 255, |
|
|
577 | frsize => 1024, |
|
|
578 | fsid => 1810 |
|
|
579 | } |
|
|
580 | |
|
|
581 | |
430 | =item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
582 | =item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
431 | |
583 | |
432 | Works like perl's C<utime> function (including the special case of $atime |
584 | Works like perl's C<utime> function (including the special case of $atime |
433 | and $mtime being undef). Fractional times are supported if the underlying |
585 | and $mtime being undef). Fractional times are supported if the underlying |
434 | syscalls support them. |
586 | syscalls support them. |
… | |
… | |
472 | |
624 | |
473 | Asynchronously unlink (delete) a file and call the callback with the |
625 | Asynchronously unlink (delete) a file and call the callback with the |
474 | result code. |
626 | result code. |
475 | |
627 | |
476 | |
628 | |
477 | =item aio_mknod $path, $mode, $dev, $callback->($status) |
629 | =item aio_mknod $pathname, $mode, $dev, $callback->($status) |
478 | |
630 | |
479 | [EXPERIMENTAL] |
631 | [EXPERIMENTAL] |
480 | |
632 | |
481 | Asynchronously create a device node (or fifo). See mknod(2). |
633 | Asynchronously create a device node (or fifo). See mknod(2). |
482 | |
634 | |
483 | The only (POSIX-) portable way of calling this function is: |
635 | The only (POSIX-) portable way of calling this function is: |
484 | |
636 | |
485 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
637 | aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
486 | |
638 | |
|
|
639 | See C<aio_stat> for info about some potentially helpful extra constants |
|
|
640 | and functions. |
487 | |
641 | |
488 | =item aio_link $srcpath, $dstpath, $callback->($status) |
642 | =item aio_link $srcpath, $dstpath, $callback->($status) |
489 | |
643 | |
490 | Asynchronously create a new link to the existing object at C<$srcpath> at |
644 | Asynchronously create a new link to the existing object at C<$srcpath> at |
491 | the path C<$dstpath> and call the callback with the result code. |
645 | the path C<$dstpath> and call the callback with the result code. |
… | |
… | |
495 | |
649 | |
496 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
650 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
497 | the path C<$dstpath> and call the callback with the result code. |
651 | the path C<$dstpath> and call the callback with the result code. |
498 | |
652 | |
499 | |
653 | |
500 | =item aio_readlink $path, $callback->($link) |
654 | =item aio_readlink $pathname, $callback->($link) |
501 | |
655 | |
502 | Asynchronously read the symlink specified by C<$path> and pass it to |
656 | Asynchronously read the symlink specified by C<$path> and pass it to |
503 | the callback. If an error occurs, nothing or undef gets passed to the |
657 | the callback. If an error occurs, nothing or undef gets passed to the |
504 | callback. |
658 | callback. |
505 | |
659 | |
506 | |
660 | |
|
|
661 | =item aio_realpath $pathname, $callback->($path) |
|
|
662 | |
|
|
663 | Asynchronously make the path absolute and resolve any symlinks in |
|
|
664 | C<$path>. The resulting path only consists of directories (Same as |
|
|
665 | L<Cwd::realpath>). |
|
|
666 | |
|
|
667 | This request can be used to get the absolute path of the current working |
|
|
668 | directory by passing it a path of F<.> (a single dot). |
|
|
669 | |
|
|
670 | |
507 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
671 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
508 | |
672 | |
509 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
673 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
510 | rename(2) and call the callback with the result code. |
674 | rename(2) and call the callback with the result code. |
511 | |
675 | |
… | |
… | |
527 | |
691 | |
528 | Unlike the POSIX call of the same name, C<aio_readdir> reads an entire |
692 | Unlike the POSIX call of the same name, C<aio_readdir> reads an entire |
529 | directory (i.e. opendir + readdir + closedir). The entries will not be |
693 | directory (i.e. opendir + readdir + closedir). The entries will not be |
530 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
694 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
531 | |
695 | |
532 | The callback a single argument which is either C<undef> or an array-ref |
696 | The callback is passed a single argument which is either C<undef> or an |
533 | with the filenames. |
697 | array-ref with the filenames. |
534 | |
698 | |
535 | |
699 | |
|
|
700 | =item aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
|
|
701 | |
|
|
702 | Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to |
|
|
703 | tune behaviour and output format. In case of an error, C<$entries> will be |
|
|
704 | C<undef>. |
|
|
705 | |
|
|
706 | The flags are a combination of the following constants, ORed together (the |
|
|
707 | flags will also be passed to the callback, possibly modified): |
|
|
708 | |
|
|
709 | =over 4 |
|
|
710 | |
|
|
711 | =item IO::AIO::READDIR_DENTS |
|
|
712 | |
|
|
713 | When this flag is off, then the callback gets an arrayref consisting of |
|
|
714 | names only (as with C<aio_readdir>), otherwise it gets an arrayref with |
|
|
715 | C<[$name, $type, $inode]> arrayrefs, each describing a single directory |
|
|
716 | entry in more detail. |
|
|
717 | |
|
|
718 | C<$name> is the name of the entry. |
|
|
719 | |
|
|
720 | C<$type> is one of the C<IO::AIO::DT_xxx> constants: |
|
|
721 | |
|
|
722 | C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, |
|
|
723 | C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, |
|
|
724 | C<IO::AIO::DT_WHT>. |
|
|
725 | |
|
|
726 | C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to |
|
|
727 | know, you have to run stat yourself. Also, for speed reasons, the C<$type> |
|
|
728 | scalars are read-only: you can not modify them. |
|
|
729 | |
|
|
730 | C<$inode> is the inode number (which might not be exact on systems with 64 |
|
|
731 | bit inode numbers and 32 bit perls). This field has unspecified content on |
|
|
732 | systems that do not deliver the inode information. |
|
|
733 | |
|
|
734 | =item IO::AIO::READDIR_DIRS_FIRST |
|
|
735 | |
|
|
736 | When this flag is set, then the names will be returned in an order where |
|
|
737 | likely directories come first, in optimal stat order. This is useful when |
|
|
738 | you need to quickly find directories, or you want to find all directories |
|
|
739 | while avoiding to stat() each entry. |
|
|
740 | |
|
|
741 | If the system returns type information in readdir, then this is used |
|
|
742 | to find directories directly. Otherwise, likely directories are names |
|
|
743 | beginning with ".", or otherwise names with no dots, of which names with |
|
|
744 | short names are tried first. |
|
|
745 | |
|
|
746 | =item IO::AIO::READDIR_STAT_ORDER |
|
|
747 | |
|
|
748 | When this flag is set, then the names will be returned in an order |
|
|
749 | suitable for stat()'ing each one. That is, when you plan to stat() |
|
|
750 | all files in the given directory, then the returned order will likely |
|
|
751 | be fastest. |
|
|
752 | |
|
|
753 | If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then |
|
|
754 | the likely dirs come first, resulting in a less optimal stat order. |
|
|
755 | |
|
|
756 | =item IO::AIO::READDIR_FOUND_UNKNOWN |
|
|
757 | |
|
|
758 | This flag should not be set when calling C<aio_readdirx>. Instead, it |
|
|
759 | is being set by C<aio_readdirx>, when any of the C<$type>'s found were |
|
|
760 | C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all |
|
|
761 | C<$type>'s are known, which can be used to speed up some algorithms. |
|
|
762 | |
|
|
763 | =back |
|
|
764 | |
|
|
765 | |
536 | =item aio_load $path, $data, $callback->($status) |
766 | =item aio_load $pathname, $data, $callback->($status) |
537 | |
767 | |
538 | This is a composite request that tries to fully load the given file into |
768 | This is a composite request that tries to fully load the given file into |
539 | memory. Status is the same as with aio_read. |
769 | memory. Status is the same as with aio_read. |
540 | |
770 | |
541 | =cut |
771 | =cut |
… | |
… | |
563 | |
793 | |
564 | =item aio_copy $srcpath, $dstpath, $callback->($status) |
794 | =item aio_copy $srcpath, $dstpath, $callback->($status) |
565 | |
795 | |
566 | Try to copy the I<file> (directories not supported as either source or |
796 | Try to copy the I<file> (directories not supported as either source or |
567 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
797 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
568 | the C<0> (error) or C<-1> ok. |
798 | a status of C<0> (ok) or C<-1> (error, see C<$!>). |
569 | |
799 | |
570 | This is a composite request that it creates the destination file with |
800 | This is a composite request that creates the destination file with |
571 | mode 0200 and copies the contents of the source file into it using |
801 | mode 0200 and copies the contents of the source file into it using |
572 | C<aio_sendfile>, followed by restoring atime, mtime, access mode and |
802 | C<aio_sendfile>, followed by restoring atime, mtime, access mode and |
573 | uid/gid, in that order. |
803 | uid/gid, in that order. |
574 | |
804 | |
575 | If an error occurs, the partial destination file will be unlinked, if |
805 | If an error occurs, the partial destination file will be unlinked, if |
… | |
… | |
585 | my $grp = aio_group $cb; |
815 | my $grp = aio_group $cb; |
586 | |
816 | |
587 | aioreq_pri $pri; |
817 | aioreq_pri $pri; |
588 | add $grp aio_open $src, O_RDONLY, 0, sub { |
818 | add $grp aio_open $src, O_RDONLY, 0, sub { |
589 | if (my $src_fh = $_[0]) { |
819 | if (my $src_fh = $_[0]) { |
590 | my @stat = stat $src_fh; |
820 | my @stat = stat $src_fh; # hmm, might block over nfs? |
591 | |
821 | |
592 | aioreq_pri $pri; |
822 | aioreq_pri $pri; |
593 | add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { |
823 | add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { |
594 | if (my $dst_fh = $_[0]) { |
824 | if (my $dst_fh = $_[0]) { |
595 | aioreq_pri $pri; |
825 | aioreq_pri $pri; |
596 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
826 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
597 | if ($_[0] == $stat[7]) { |
827 | if ($_[0] == $stat[7]) { |
598 | $grp->result (0); |
828 | $grp->result (0); |
599 | close $src_fh; |
829 | close $src_fh; |
600 | |
830 | |
601 | # those should not normally block. should. should. |
831 | my $ch = sub { |
602 | utime $stat[8], $stat[9], $dst; |
832 | aioreq_pri $pri; |
603 | chmod $stat[2] & 07777, $dst_fh; |
833 | add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub { |
604 | chown $stat[4], $stat[5], $dst_fh; |
834 | aioreq_pri $pri; |
|
|
835 | add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub { |
|
|
836 | aioreq_pri $pri; |
|
|
837 | add $grp aio_close $dst_fh; |
|
|
838 | } |
|
|
839 | }; |
|
|
840 | }; |
605 | |
841 | |
606 | aioreq_pri $pri; |
842 | aioreq_pri $pri; |
607 | add $grp aio_close $dst_fh; |
843 | add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub { |
|
|
844 | if ($_[0] < 0 && $! == ENOSYS) { |
|
|
845 | aioreq_pri $pri; |
|
|
846 | add $grp aio_utime $dst, $stat[8], $stat[9], $ch; |
|
|
847 | } else { |
|
|
848 | $ch->(); |
|
|
849 | } |
|
|
850 | }; |
608 | } else { |
851 | } else { |
609 | $grp->result (-1); |
852 | $grp->result (-1); |
610 | close $src_fh; |
853 | close $src_fh; |
611 | close $dst_fh; |
854 | close $dst_fh; |
612 | |
855 | |
… | |
… | |
629 | |
872 | |
630 | =item aio_move $srcpath, $dstpath, $callback->($status) |
873 | =item aio_move $srcpath, $dstpath, $callback->($status) |
631 | |
874 | |
632 | Try to move the I<file> (directories not supported as either source or |
875 | Try to move the I<file> (directories not supported as either source or |
633 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
876 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
634 | the C<0> (error) or C<-1> ok. |
877 | a status of C<0> (ok) or C<-1> (error, see C<$!>). |
635 | |
878 | |
636 | This is a composite request that tries to rename(2) the file first. If |
879 | This is a composite request that tries to rename(2) the file first; if |
637 | rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if |
880 | rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if |
638 | that is successful, unlinking the C<$srcpath>. |
881 | that is successful, unlinks the C<$srcpath>. |
639 | |
882 | |
640 | =cut |
883 | =cut |
641 | |
884 | |
642 | sub aio_move($$;$) { |
885 | sub aio_move($$;$) { |
643 | my ($src, $dst, $cb) = @_; |
886 | my ($src, $dst, $cb) = @_; |
… | |
… | |
650 | if ($_[0] && $! == EXDEV) { |
893 | if ($_[0] && $! == EXDEV) { |
651 | aioreq_pri $pri; |
894 | aioreq_pri $pri; |
652 | add $grp aio_copy $src, $dst, sub { |
895 | add $grp aio_copy $src, $dst, sub { |
653 | $grp->result ($_[0]); |
896 | $grp->result ($_[0]); |
654 | |
897 | |
655 | if (!$_[0]) { |
898 | unless ($_[0]) { |
656 | aioreq_pri $pri; |
899 | aioreq_pri $pri; |
657 | add $grp aio_unlink $src; |
900 | add $grp aio_unlink $src; |
658 | } |
901 | } |
659 | }; |
902 | }; |
660 | } else { |
903 | } else { |
… | |
… | |
663 | }; |
906 | }; |
664 | |
907 | |
665 | $grp |
908 | $grp |
666 | } |
909 | } |
667 | |
910 | |
668 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
911 | =item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
669 | |
912 | |
670 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
913 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
671 | efficiently separate the entries of directory C<$path> into two sets of |
914 | efficiently separate the entries of directory C<$path> into two sets of |
672 | names, directories you can recurse into (directories), and ones you cannot |
915 | names, directories you can recurse into (directories), and ones you cannot |
673 | recurse into (everything else, including symlinks to directories). |
916 | recurse into (everything else, including symlinks to directories). |
… | |
… | |
690 | |
933 | |
691 | Implementation notes. |
934 | Implementation notes. |
692 | |
935 | |
693 | The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. |
936 | The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. |
694 | |
937 | |
|
|
938 | If readdir returns file type information, then this is used directly to |
|
|
939 | find directories. |
|
|
940 | |
695 | After reading the directory, the modification time, size etc. of the |
941 | Otherwise, after reading the directory, the modification time, size etc. |
696 | directory before and after the readdir is checked, and if they match (and |
942 | of the directory before and after the readdir is checked, and if they |
697 | isn't the current time), the link count will be used to decide how many |
943 | match (and isn't the current time), the link count will be used to decide |
698 | entries are directories (if >= 2). Otherwise, no knowledge of the number |
944 | how many entries are directories (if >= 2). Otherwise, no knowledge of the |
699 | of subdirectories will be assumed. |
945 | number of subdirectories will be assumed. |
700 | |
946 | |
701 | Then entries will be sorted into likely directories (everything without |
947 | Then entries will be sorted into likely directories a non-initial dot |
702 | a non-initial dot currently) and likely non-directories (everything |
948 | currently) and likely non-directories (see C<aio_readdirx>). Then every |
703 | else). Then every entry plus an appended C</.> will be C<stat>'ed, |
949 | entry plus an appended C</.> will be C<stat>'ed, likely directories first, |
704 | likely directories first. If that succeeds, it assumes that the entry |
950 | in order of their inode numbers. If that succeeds, it assumes that the |
705 | is a directory or a symlink to directory (which will be checked |
951 | entry is a directory or a symlink to directory (which will be checked |
706 | seperately). This is often faster than stat'ing the entry itself because |
952 | separately). This is often faster than stat'ing the entry itself because |
707 | filesystems might detect the type of the entry without reading the inode |
953 | filesystems might detect the type of the entry without reading the inode |
708 | data (e.g. ext2fs filetype feature). |
954 | data (e.g. ext2fs filetype feature), even on systems that cannot return |
|
|
955 | the filetype information on readdir. |
709 | |
956 | |
710 | If the known number of directories (link count - 2) has been reached, the |
957 | If the known number of directories (link count - 2) has been reached, the |
711 | rest of the entries is assumed to be non-directories. |
958 | rest of the entries is assumed to be non-directories. |
712 | |
959 | |
713 | This only works with certainty on POSIX (= UNIX) filesystems, which |
960 | This only works with certainty on POSIX (= UNIX) filesystems, which |
… | |
… | |
726 | |
973 | |
727 | my $grp = aio_group $cb; |
974 | my $grp = aio_group $cb; |
728 | |
975 | |
729 | $maxreq = 4 if $maxreq <= 0; |
976 | $maxreq = 4 if $maxreq <= 0; |
730 | |
977 | |
731 | # stat once |
978 | # get a wd object |
732 | aioreq_pri $pri; |
979 | aioreq_pri $pri; |
733 | add $grp aio_stat $path, sub { |
980 | add $grp aio_wd $path, sub { |
|
|
981 | $_[0] |
734 | return $grp->result () if $_[0]; |
982 | or return $grp->result (); |
735 | my $now = time; |
|
|
736 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
|
|
737 | |
983 | |
738 | # read the directory entries |
984 | my $wd = [shift, "."]; |
|
|
985 | |
|
|
986 | # stat once |
739 | aioreq_pri $pri; |
987 | aioreq_pri $pri; |
740 | add $grp aio_readdir $path, sub { |
988 | add $grp aio_stat $wd, sub { |
741 | my $entries = shift |
|
|
742 | or return $grp->result (); |
989 | return $grp->result () if $_[0]; |
|
|
990 | my $now = time; |
|
|
991 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
743 | |
992 | |
744 | # stat the dir another time |
993 | # read the directory entries |
745 | aioreq_pri $pri; |
994 | aioreq_pri $pri; |
|
|
995 | add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { |
|
|
996 | my $entries = shift |
|
|
997 | or return $grp->result (); |
|
|
998 | |
|
|
999 | # stat the dir another time |
|
|
1000 | aioreq_pri $pri; |
746 | add $grp aio_stat $path, sub { |
1001 | add $grp aio_stat $wd, sub { |
747 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
1002 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
748 | |
1003 | |
749 | my $ndirs; |
1004 | my $ndirs; |
750 | |
1005 | |
751 | # take the slow route if anything looks fishy |
1006 | # take the slow route if anything looks fishy |
752 | if ($hash1 ne $hash2 or (stat _)[9] == $now) { |
1007 | if ($hash1 ne $hash2 or (stat _)[9] == $now) { |
753 | $ndirs = -1; |
1008 | $ndirs = -1; |
754 | } else { |
1009 | } else { |
755 | # if nlink == 2, we are finished |
1010 | # if nlink == 2, we are finished |
756 | # on non-posix-fs's, we rely on nlink < 2 |
1011 | # for non-posix-fs's, we rely on nlink < 2 |
757 | $ndirs = (stat _)[3] - 2 |
1012 | $ndirs = (stat _)[3] - 2 |
758 | or return $grp->result ([], $entries); |
1013 | or return $grp->result ([], $entries); |
759 | } |
1014 | } |
760 | |
1015 | |
761 | # sort into likely dirs and likely nondirs |
|
|
762 | # dirs == files without ".", short entries first |
|
|
763 | $entries = [map $_->[0], |
|
|
764 | sort { $b->[1] cmp $a->[1] } |
|
|
765 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
|
|
766 | @$entries]; |
|
|
767 | |
|
|
768 | my (@dirs, @nondirs); |
1016 | my (@dirs, @nondirs); |
769 | |
1017 | |
770 | my $statgrp = add $grp aio_group sub { |
1018 | my $statgrp = add $grp aio_group sub { |
771 | $grp->result (\@dirs, \@nondirs); |
1019 | $grp->result (\@dirs, \@nondirs); |
772 | }; |
1020 | }; |
773 | |
1021 | |
774 | limit $statgrp $maxreq; |
1022 | limit $statgrp $maxreq; |
775 | feed $statgrp sub { |
1023 | feed $statgrp sub { |
776 | return unless @$entries; |
1024 | return unless @$entries; |
777 | my $entry = pop @$entries; |
1025 | my $entry = shift @$entries; |
778 | |
1026 | |
779 | aioreq_pri $pri; |
1027 | aioreq_pri $pri; |
|
|
1028 | $wd->[1] = "$entry/."; |
780 | add $statgrp aio_stat "$path/$entry/.", sub { |
1029 | add $statgrp aio_stat $wd, sub { |
781 | if ($_[0] < 0) { |
1030 | if ($_[0] < 0) { |
782 | push @nondirs, $entry; |
1031 | push @nondirs, $entry; |
783 | } else { |
1032 | } else { |
784 | # need to check for real directory |
1033 | # need to check for real directory |
785 | aioreq_pri $pri; |
1034 | aioreq_pri $pri; |
|
|
1035 | $wd->[1] = $entry; |
786 | add $statgrp aio_lstat "$path/$entry", sub { |
1036 | add $statgrp aio_lstat $wd, sub { |
787 | if (-d _) { |
1037 | if (-d _) { |
788 | push @dirs, $entry; |
1038 | push @dirs, $entry; |
789 | |
1039 | |
790 | unless (--$ndirs) { |
1040 | unless (--$ndirs) { |
791 | push @nondirs, @$entries; |
1041 | push @nondirs, @$entries; |
792 | feed $statgrp; |
1042 | feed $statgrp; |
|
|
1043 | } |
|
|
1044 | } else { |
|
|
1045 | push @nondirs, $entry; |
793 | } |
1046 | } |
794 | } else { |
|
|
795 | push @nondirs, $entry; |
|
|
796 | } |
1047 | } |
797 | } |
1048 | } |
798 | } |
1049 | }; |
799 | }; |
1050 | }; |
800 | }; |
1051 | }; |
801 | }; |
1052 | }; |
802 | }; |
1053 | }; |
803 | }; |
1054 | }; |
804 | |
1055 | |
805 | $grp |
1056 | $grp |
806 | } |
1057 | } |
807 | |
1058 | |
808 | =item aio_rmtree $path, $callback->($status) |
1059 | =item aio_rmtree $pathname, $callback->($status) |
809 | |
1060 | |
810 | Delete a directory tree starting (and including) C<$path>, return the |
1061 | Delete a directory tree starting (and including) C<$path>, return the |
811 | status of the final C<rmdir> only. This is a composite request that |
1062 | status of the final C<rmdir> only. This is a composite request that |
812 | uses C<aio_scandir> to recurse into and rmdir directories, and unlink |
1063 | uses C<aio_scandir> to recurse into and rmdir directories, and unlink |
813 | everything else. |
1064 | everything else. |
… | |
… | |
855 | callback with the fdatasync result code. |
1106 | callback with the fdatasync result code. |
856 | |
1107 | |
857 | If this call isn't available because your OS lacks it or it couldn't be |
1108 | If this call isn't available because your OS lacks it or it couldn't be |
858 | detected, it will be emulated by calling C<fsync> instead. |
1109 | detected, it will be emulated by calling C<fsync> instead. |
859 | |
1110 | |
|
|
1111 | =item aio_syncfs $fh, $callback->($status) |
|
|
1112 | |
|
|
1113 | Asynchronously call the syncfs syscall to sync the filesystem associated |
|
|
1114 | to the given filehandle and call the callback with the syncfs result |
|
|
1115 | code. If syncfs is not available, calls sync(), but returns C<-1> and sets |
|
|
1116 | errno to C<ENOSYS> nevertheless. |
|
|
1117 | |
|
|
1118 | =item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
|
|
1119 | |
|
|
1120 | Sync the data portion of the file specified by C<$offset> and C<$length> |
|
|
1121 | to disk (but NOT the metadata), by calling the Linux-specific |
|
|
1122 | sync_file_range call. If sync_file_range is not available or it returns |
|
|
1123 | ENOSYS, then fdatasync or fsync is being substituted. |
|
|
1124 | |
|
|
1125 | C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, |
|
|
1126 | C<IO::AIO::SYNC_FILE_RANGE_WRITE> and |
|
|
1127 | C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range |
|
|
1128 | manpage for details. |
|
|
1129 | |
860 | =item aio_pathsync $path, $callback->($status) |
1130 | =item aio_pathsync $pathname, $callback->($status) |
861 | |
1131 | |
862 | This request tries to open, fsync and close the given path. This is a |
1132 | This request tries to open, fsync and close the given path. This is a |
863 | composite request intended tosync directories after directory operations |
1133 | composite request intended to sync directories after directory operations |
864 | (E.g. rename). This might not work on all operating systems or have any |
1134 | (E.g. rename). This might not work on all operating systems or have any |
865 | specific effect, but usually it makes sure that directory changes get |
1135 | specific effect, but usually it makes sure that directory changes get |
866 | written to disc. It works for anything that can be opened for read-only, |
1136 | written to disc. It works for anything that can be opened for read-only, |
867 | not just directories. |
1137 | not just directories. |
|
|
1138 | |
|
|
1139 | Future versions of this function might fall back to other methods when |
|
|
1140 | C<fsync> on the directory fails (such as calling C<sync>). |
868 | |
1141 | |
869 | Passes C<0> when everything went ok, and C<-1> on error. |
1142 | Passes C<0> when everything went ok, and C<-1> on error. |
870 | |
1143 | |
871 | =cut |
1144 | =cut |
872 | |
1145 | |
… | |
… | |
893 | }; |
1166 | }; |
894 | |
1167 | |
895 | $grp |
1168 | $grp |
896 | } |
1169 | } |
897 | |
1170 | |
|
|
1171 | =item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
|
|
1172 | |
|
|
1173 | This is a rather advanced IO::AIO call, which only works on mmap(2)ed |
|
|
1174 | scalars (see the C<IO::AIO::mmap> function, although it also works on data |
|
|
1175 | scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the |
|
|
1176 | scalar must only be modified in-place while an aio operation is pending on |
|
|
1177 | it). |
|
|
1178 | |
|
|
1179 | It calls the C<msync> function of your OS, if available, with the memory |
|
|
1180 | area starting at C<$offset> in the string and ending C<$length> bytes |
|
|
1181 | later. If C<$length> is negative, counts from the end, and if C<$length> |
|
|
1182 | is C<undef>, then it goes till the end of the string. The flags can be |
|
|
1183 | a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and |
|
|
1184 | C<IO::AIO::MS_SYNC>. |
|
|
1185 | |
|
|
1186 | =item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
|
|
1187 | |
|
|
1188 | This is a rather advanced IO::AIO call, which works best on mmap(2)ed |
|
|
1189 | scalars. |
|
|
1190 | |
|
|
1191 | It touches (reads or writes) all memory pages in the specified |
|
|
1192 | range inside the scalar. All caveats and parameters are the same |
|
|
1193 | as for C<aio_msync>, above, except for flags, which must be either |
|
|
1194 | C<0> (which reads all pages and ensures they are instantiated) or |
|
|
1195 | C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and |
|
|
1196 | writing an octet from it, which dirties the page). |
|
|
1197 | |
|
|
1198 | =item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
|
|
1199 | |
|
|
1200 | This is a rather advanced IO::AIO call, which works best on mmap(2)ed |
|
|
1201 | scalars. |
|
|
1202 | |
|
|
1203 | It reads in all the pages of the underlying storage into memory (if any) |
|
|
1204 | and locks them, so they are not getting swapped/paged out or removed. |
|
|
1205 | |
|
|
1206 | If C<$length> is undefined, then the scalar will be locked till the end. |
|
|
1207 | |
|
|
1208 | On systems that do not implement C<mlock>, this function returns C<-1> |
|
|
1209 | and sets errno to C<ENOSYS>. |
|
|
1210 | |
|
|
1211 | Note that the corresponding C<munlock> is synchronous and is |
|
|
1212 | documented under L<MISCELLANEOUS FUNCTIONS>. |
|
|
1213 | |
|
|
1214 | Example: open a file, mmap and mlock it - both will be undone when |
|
|
1215 | C<$data> gets destroyed. |
|
|
1216 | |
|
|
1217 | open my $fh, "<", $path or die "$path: $!"; |
|
|
1218 | my $data; |
|
|
1219 | IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; |
|
|
1220 | aio_mlock $data; # mlock in background |
|
|
1221 | |
|
|
1222 | =item aio_mlockall $flags, $callback->($status) |
|
|
1223 | |
|
|
1224 | Calls the C<mlockall> function with the given C<$flags> (a combination of |
|
|
1225 | C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). |
|
|
1226 | |
|
|
1227 | On systems that do not implement C<mlockall>, this function returns C<-1> |
|
|
1228 | and sets errno to C<ENOSYS>. |
|
|
1229 | |
|
|
1230 | Note that the corresponding C<munlockall> is synchronous and is |
|
|
1231 | documented under L<MISCELLANEOUS FUNCTIONS>. |
|
|
1232 | |
|
|
1233 | Example: asynchronously lock all current and future pages into memory. |
|
|
1234 | |
|
|
1235 | aio_mlockall IO::AIO::MCL_FUTURE; |
|
|
1236 | |
898 | =item aio_group $callback->(...) |
1237 | =item aio_group $callback->(...) |
899 | |
1238 | |
900 | This is a very special aio request: Instead of doing something, it is a |
1239 | This is a very special aio request: Instead of doing something, it is a |
901 | container for other aio requests, which is useful if you want to bundle |
1240 | container for other aio requests, which is useful if you want to bundle |
902 | many requests into a single, composite, request with a definite callback |
1241 | many requests into a single, composite, request with a definite callback |
… | |
… | |
939 | immense (it blocks a thread for a long time) so do not use this function |
1278 | immense (it blocks a thread for a long time) so do not use this function |
940 | except to put your application under artificial I/O pressure. |
1279 | except to put your application under artificial I/O pressure. |
941 | |
1280 | |
942 | =back |
1281 | =back |
943 | |
1282 | |
|
|
1283 | |
|
|
1284 | =head2 IO::AIO::WD - multiple working directories |
|
|
1285 | |
|
|
1286 | Your process only has one current working directory, which is used by all |
|
|
1287 | threads. This makes it hard to use relative paths (some other component |
|
|
1288 | could call C<chdir> at any time, and it is hard to control when the path |
|
|
1289 | will be used by IO::AIO). |
|
|
1290 | |
|
|
1291 | One solution for this is to always use absolute paths. This usually works, |
|
|
1292 | but can be quite slow (the kernel has to walk the whole path on every |
|
|
1293 | access), and can also be a hassle to implement. |
|
|
1294 | |
|
|
1295 | Newer POSIX systems have a number of functions (openat, fdopendir, |
|
|
1296 | futimensat and so on) that make it possible to specify working directories |
|
|
1297 | per operation. |
|
|
1298 | |
|
|
1299 | For portability, and because the clowns who "designed", or shall I write, |
|
|
1300 | perpetrated this new interface were obviously half-drunk, this abstraction |
|
|
1301 | cannot be perfect, though. |
|
|
1302 | |
|
|
1303 | IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD |
|
|
1304 | object. This object stores the canonicalised, absolute version of the |
|
|
1305 | path, and on systems that allow it, also a directory file descriptor. |
|
|
1306 | |
|
|
1307 | Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat> |
|
|
1308 | or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD |
|
|
1309 | object and a pathname instead. If the pathname is absolute, the |
|
|
1310 | IO::AIO::WD object is ignored, otherwise the pathname is resolved relative |
|
|
1311 | to that IO::AIO::WD object. |
|
|
1312 | |
|
|
1313 | For example, to get a wd object for F</etc> and then stat F<passwd> |
|
|
1314 | inside, you would write: |
|
|
1315 | |
|
|
1316 | aio_wd "/etc", sub { |
|
|
1317 | my $etcdir = shift; |
|
|
1318 | |
|
|
1319 | # although $etcdir can be undef on error, there is generally no reason |
|
|
1320 | # to check for errors here, as aio_stat will fail with ENOENT |
|
|
1321 | # when $etcdir is undef. |
|
|
1322 | |
|
|
1323 | aio_stat [$etcdir, "passwd"], sub { |
|
|
1324 | # yay |
|
|
1325 | }; |
|
|
1326 | }; |
|
|
1327 | |
|
|
1328 | This shows that creating an IO::AIO::WD object is itself a potentially |
|
|
1329 | blocking operation, which is why it is done asynchronously. |
|
|
1330 | |
|
|
1331 | As with normal pathnames, IO::AIO keeps a copy of the working directory |
|
|
1332 | object and the pathname string, so you could write the following without |
|
|
1333 | causing any issues due to C<$path> getting reused: |
|
|
1334 | |
|
|
1335 | my $path = [$wd, undef]; |
|
|
1336 | |
|
|
1337 | for my $name (qw(abc def ghi)) { |
|
|
1338 | $path->[1] = $name; |
|
|
1339 | aio_stat $path, sub { |
|
|
1340 | # ... |
|
|
1341 | }; |
|
|
1342 | } |
|
|
1343 | |
|
|
1344 | There are some caveats: when directories get renamed (or deleted), the |
|
|
1345 | pathname string doesn't change, so will point to the new directory (or |
|
|
1346 | nowhere at all), while the directory fd, if available on the system, |
|
|
1347 | will still point to the original directory. Most functions accepting a |
|
|
1348 | pathname will use the directory fd on newer systems, and the string on |
|
|
1349 | older systems. Some functions (such as realpath) will always rely on the |
|
|
1350 | string form of the pathname. |
|
|
1351 | |
|
|
1352 | So this fucntionality is mainly useful to get some protection against |
|
|
1353 | C<chdir>, to easily get an absolute path out of a relative path for future |
|
|
1354 | reference, and to speed up doing many operations in the same directory |
|
|
1355 | (e.g. when stat'ing all files in a directory). |
|
|
1356 | |
|
|
1357 | The following functions implement this working directory abstraction: |
|
|
1358 | |
|
|
1359 | =over 4 |
|
|
1360 | |
|
|
1361 | =item aio_wd $pathname, $callback->($wd) |
|
|
1362 | |
|
|
1363 | Asynchonously canonicalise the given pathname and convert it to an |
|
|
1364 | IO::AIO::WD object representing it. If possible and supported on the |
|
|
1365 | system, also open a directory fd to speed up pathname resolution relative |
|
|
1366 | to this working directory. |
|
|
1367 | |
|
|
1368 | If something goes wrong, then C<undef> is passwd to the callback instead |
|
|
1369 | of a working directory object and C<$!> is set appropriately. Since |
|
|
1370 | passing C<undef> as working directory component of a pathname fails the |
|
|
1371 | request with C<ENOENT>, there is often no need for error checking in the |
|
|
1372 | C<aio_wd> callback, as future requests using the value will fail in the |
|
|
1373 | expected way. |
|
|
1374 | |
|
|
1375 | If this call isn't available because your OS lacks it or it couldn't be |
|
|
1376 | detected, it will be emulated by calling C<fsync> instead. |
|
|
1377 | |
|
|
1378 | =item IO::AIO::CWD |
|
|
1379 | |
|
|
1380 | This is a compiletime constant (object) that represents the process |
|
|
1381 | current working directory. |
|
|
1382 | |
|
|
1383 | Specifying this object as working directory object for a pathname is as |
|
|
1384 | if the pathname would be specified directly, without a directory object, |
|
|
1385 | e.g., these calls are functionally identical: |
|
|
1386 | |
|
|
1387 | aio_stat "somefile", sub { ... }; |
|
|
1388 | aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; |
|
|
1389 | |
|
|
1390 | =back |
|
|
1391 | |
|
|
1392 | |
944 | =head2 IO::AIO::REQ CLASS |
1393 | =head2 IO::AIO::REQ CLASS |
945 | |
1394 | |
946 | All non-aggregate C<aio_*> functions return an object of this class when |
1395 | All non-aggregate C<aio_*> functions return an object of this class when |
947 | called in non-void context. |
1396 | called in non-void context. |
948 | |
1397 | |
… | |
… | |
951 | =item cancel $req |
1400 | =item cancel $req |
952 | |
1401 | |
953 | Cancels the request, if possible. Has the effect of skipping execution |
1402 | Cancels the request, if possible. Has the effect of skipping execution |
954 | when entering the B<execute> state and skipping calling the callback when |
1403 | when entering the B<execute> state and skipping calling the callback when |
955 | entering the the B<result> state, but will leave the request otherwise |
1404 | entering the the B<result> state, but will leave the request otherwise |
956 | untouched. That means that requests that currently execute will not be |
1405 | untouched (with the exception of readdir). That means that requests that |
957 | stopped and resources held by the request will not be freed prematurely. |
1406 | currently execute will not be stopped and resources held by the request |
|
|
1407 | will not be freed prematurely. |
958 | |
1408 | |
959 | =item cb $req $callback->(...) |
1409 | =item cb $req $callback->(...) |
960 | |
1410 | |
961 | Replace (or simply set) the callback registered to the request. |
1411 | Replace (or simply set) the callback registered to the request. |
962 | |
1412 | |
… | |
… | |
1013 | Their lifetime, simplified, looks like this: when they are empty, they |
1463 | Their lifetime, simplified, looks like this: when they are empty, they |
1014 | will finish very quickly. If they contain only requests that are in the |
1464 | will finish very quickly. If they contain only requests that are in the |
1015 | C<done> state, they will also finish. Otherwise they will continue to |
1465 | C<done> state, they will also finish. Otherwise they will continue to |
1016 | exist. |
1466 | exist. |
1017 | |
1467 | |
1018 | That means after creating a group you have some time to add requests. And |
1468 | That means after creating a group you have some time to add requests |
1019 | in the callbacks of those requests, you can add further requests to the |
1469 | (precisely before the callback has been invoked, which is only done within |
1020 | group. And only when all those requests have finished will the the group |
1470 | the C<poll_cb>). And in the callbacks of those requests, you can add |
1021 | itself finish. |
1471 | further requests to the group. And only when all those requests have |
|
|
1472 | finished will the the group itself finish. |
1022 | |
1473 | |
1023 | =over 4 |
1474 | =over 4 |
1024 | |
1475 | |
1025 | =item add $grp ... |
1476 | =item add $grp ... |
1026 | |
1477 | |
… | |
… | |
1034 | |
1485 | |
1035 | =item $grp->cancel_subs |
1486 | =item $grp->cancel_subs |
1036 | |
1487 | |
1037 | Cancel all subrequests and clears any feeder, but not the group request |
1488 | Cancel all subrequests and clears any feeder, but not the group request |
1038 | itself. Useful when you queued a lot of events but got a result early. |
1489 | itself. Useful when you queued a lot of events but got a result early. |
|
|
1490 | |
|
|
1491 | The group request will finish normally (you cannot add requests to the |
|
|
1492 | group). |
1039 | |
1493 | |
1040 | =item $grp->result (...) |
1494 | =item $grp->result (...) |
1041 | |
1495 | |
1042 | Set the result value(s) that will be passed to the group callback when all |
1496 | Set the result value(s) that will be passed to the group callback when all |
1043 | subrequests have finished and set the groups errno to the current value |
1497 | subrequests have finished and set the groups errno to the current value |
… | |
… | |
1059 | =item feed $grp $callback->($grp) |
1513 | =item feed $grp $callback->($grp) |
1060 | |
1514 | |
1061 | Sets a feeder/generator on this group: every group can have an attached |
1515 | Sets a feeder/generator on this group: every group can have an attached |
1062 | generator that generates requests if idle. The idea behind this is that, |
1516 | generator that generates requests if idle. The idea behind this is that, |
1063 | although you could just queue as many requests as you want in a group, |
1517 | although you could just queue as many requests as you want in a group, |
1064 | this might starve other requests for a potentially long time. For |
1518 | this might starve other requests for a potentially long time. For example, |
1065 | example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> |
1519 | C<aio_scandir> might generate hundreds of thousands of C<aio_stat> |
1066 | requests, delaying any later requests for a long time. |
1520 | requests, delaying any later requests for a long time. |
1067 | |
1521 | |
1068 | To avoid this, and allow incremental generation of requests, you can |
1522 | To avoid this, and allow incremental generation of requests, you can |
1069 | instead a group and set a feeder on it that generates those requests. The |
1523 | instead a group and set a feeder on it that generates those requests. The |
1070 | feed callback will be called whenever there are few enough (see C<limit>, |
1524 | feed callback will be called whenever there are few enough (see C<limit>, |
… | |
… | |
1075 | not impose any limits). |
1529 | not impose any limits). |
1076 | |
1530 | |
1077 | If the feed does not queue more requests when called, it will be |
1531 | If the feed does not queue more requests when called, it will be |
1078 | automatically removed from the group. |
1532 | automatically removed from the group. |
1079 | |
1533 | |
1080 | If the feed limit is C<0>, it will be set to C<2> automatically. |
1534 | If the feed limit is C<0> when this method is called, it will be set to |
|
|
1535 | C<2> automatically. |
1081 | |
1536 | |
1082 | Example: |
1537 | Example: |
1083 | |
1538 | |
1084 | # stat all files in @files, but only ever use four aio requests concurrently: |
1539 | # stat all files in @files, but only ever use four aio requests concurrently: |
1085 | |
1540 | |
… | |
… | |
1097 | Sets the feeder limit for the group: The feeder will be called whenever |
1552 | Sets the feeder limit for the group: The feeder will be called whenever |
1098 | the group contains less than this many requests. |
1553 | the group contains less than this many requests. |
1099 | |
1554 | |
1100 | Setting the limit to C<0> will pause the feeding process. |
1555 | Setting the limit to C<0> will pause the feeding process. |
1101 | |
1556 | |
|
|
1557 | The default value for the limit is C<0>, but note that setting a feeder |
|
|
1558 | automatically bumps it up to C<2>. |
|
|
1559 | |
1102 | =back |
1560 | =back |
1103 | |
1561 | |
1104 | =head2 SUPPORT FUNCTIONS |
1562 | =head2 SUPPORT FUNCTIONS |
1105 | |
1563 | |
1106 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
1564 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
… | |
… | |
1108 | =over 4 |
1566 | =over 4 |
1109 | |
1567 | |
1110 | =item $fileno = IO::AIO::poll_fileno |
1568 | =item $fileno = IO::AIO::poll_fileno |
1111 | |
1569 | |
1112 | Return the I<request result pipe file descriptor>. This filehandle must be |
1570 | Return the I<request result pipe file descriptor>. This filehandle must be |
1113 | polled for reading by some mechanism outside this module (e.g. Event or |
1571 | polled for reading by some mechanism outside this module (e.g. EV, Glib, |
1114 | select, see below or the SYNOPSIS). If the pipe becomes readable you have |
1572 | select and so on, see below or the SYNOPSIS). If the pipe becomes readable |
1115 | to call C<poll_cb> to check the results. |
1573 | you have to call C<poll_cb> to check the results. |
1116 | |
1574 | |
1117 | See C<poll_cb> for an example. |
1575 | See C<poll_cb> for an example. |
1118 | |
1576 | |
1119 | =item IO::AIO::poll_cb |
1577 | =item IO::AIO::poll_cb |
1120 | |
1578 | |
1121 | Process some outstanding events on the result pipe. You have to call this |
1579 | Process some outstanding events on the result pipe. You have to call |
1122 | regularly. Returns the number of events processed. Returns immediately |
1580 | this regularly. Returns C<0> if all events could be processed (or there |
1123 | when no events are outstanding. The amount of events processed depends on |
1581 | were no events to process), or C<-1> if it returned earlier for whatever |
1124 | the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. |
1582 | reason. Returns immediately when no events are outstanding. The amount of |
|
|
1583 | events processed depends on the settings of C<IO::AIO::max_poll_req> and |
|
|
1584 | C<IO::AIO::max_poll_time>. |
1125 | |
1585 | |
1126 | If not all requests were processed for whatever reason, the filehandle |
1586 | If not all requests were processed for whatever reason, the filehandle |
1127 | will still be ready when C<poll_cb> returns. |
1587 | will still be ready when C<poll_cb> returns, so normally you don't have to |
|
|
1588 | do anything special to have it called later. |
|
|
1589 | |
|
|
1590 | Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes |
|
|
1591 | ready, it can be beneficial to call this function from loops which submit |
|
|
1592 | a lot of requests, to make sure the results get processed when they become |
|
|
1593 | available and not just when the loop is finished and the event loop takes |
|
|
1594 | over again. This function returns very fast when there are no outstanding |
|
|
1595 | requests. |
1128 | |
1596 | |
1129 | Example: Install an Event watcher that automatically calls |
1597 | Example: Install an Event watcher that automatically calls |
1130 | IO::AIO::poll_cb with high priority: |
1598 | IO::AIO::poll_cb with high priority (more examples can be found in the |
|
|
1599 | SYNOPSIS section, at the top of this document): |
1131 | |
1600 | |
1132 | Event->io (fd => IO::AIO::poll_fileno, |
1601 | Event->io (fd => IO::AIO::poll_fileno, |
1133 | poll => 'r', async => 1, |
1602 | poll => 'r', async => 1, |
1134 | cb => \&IO::AIO::poll_cb); |
1603 | cb => \&IO::AIO::poll_cb); |
|
|
1604 | |
|
|
1605 | =item IO::AIO::poll_wait |
|
|
1606 | |
|
|
1607 | If there are any outstanding requests and none of them in the result |
|
|
1608 | phase, wait till the result filehandle becomes ready for reading (simply |
|
|
1609 | does a C<select> on the filehandle. This is useful if you want to |
|
|
1610 | synchronously wait for some requests to finish). |
|
|
1611 | |
|
|
1612 | See C<nreqs> for an example. |
|
|
1613 | |
|
|
1614 | =item IO::AIO::poll |
|
|
1615 | |
|
|
1616 | Waits until some requests have been handled. |
|
|
1617 | |
|
|
1618 | Returns the number of requests processed, but is otherwise strictly |
|
|
1619 | equivalent to: |
|
|
1620 | |
|
|
1621 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1622 | |
|
|
1623 | =item IO::AIO::flush |
|
|
1624 | |
|
|
1625 | Wait till all outstanding AIO requests have been handled. |
|
|
1626 | |
|
|
1627 | Strictly equivalent to: |
|
|
1628 | |
|
|
1629 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1630 | while IO::AIO::nreqs; |
1135 | |
1631 | |
1136 | =item IO::AIO::max_poll_reqs $nreqs |
1632 | =item IO::AIO::max_poll_reqs $nreqs |
1137 | |
1633 | |
1138 | =item IO::AIO::max_poll_time $seconds |
1634 | =item IO::AIO::max_poll_time $seconds |
1139 | |
1635 | |
… | |
… | |
1164 | # use a low priority so other tasks have priority |
1660 | # use a low priority so other tasks have priority |
1165 | Event->io (fd => IO::AIO::poll_fileno, |
1661 | Event->io (fd => IO::AIO::poll_fileno, |
1166 | poll => 'r', nice => 1, |
1662 | poll => 'r', nice => 1, |
1167 | cb => &IO::AIO::poll_cb); |
1663 | cb => &IO::AIO::poll_cb); |
1168 | |
1664 | |
1169 | =item IO::AIO::poll_wait |
|
|
1170 | |
|
|
1171 | If there are any outstanding requests and none of them in the result |
|
|
1172 | phase, wait till the result filehandle becomes ready for reading (simply |
|
|
1173 | does a C<select> on the filehandle. This is useful if you want to |
|
|
1174 | synchronously wait for some requests to finish). |
|
|
1175 | |
|
|
1176 | See C<nreqs> for an example. |
|
|
1177 | |
|
|
1178 | =item IO::AIO::poll |
|
|
1179 | |
|
|
1180 | Waits until some requests have been handled. |
|
|
1181 | |
|
|
1182 | Returns the number of requests processed, but is otherwise strictly |
|
|
1183 | equivalent to: |
|
|
1184 | |
|
|
1185 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1186 | |
|
|
1187 | =item IO::AIO::flush |
|
|
1188 | |
|
|
1189 | Wait till all outstanding AIO requests have been handled. |
|
|
1190 | |
|
|
1191 | Strictly equivalent to: |
|
|
1192 | |
|
|
1193 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1194 | while IO::AIO::nreqs; |
|
|
1195 | |
|
|
1196 | =back |
1665 | =back |
1197 | |
1666 | |
1198 | =head3 CONTROLLING THE NUMBER OF THREADS |
1667 | =head3 CONTROLLING THE NUMBER OF THREADS |
1199 | |
1668 | |
1200 | =over |
1669 | =over |
… | |
… | |
1233 | |
1702 | |
1234 | Under normal circumstances you don't need to call this function. |
1703 | Under normal circumstances you don't need to call this function. |
1235 | |
1704 | |
1236 | =item IO::AIO::max_idle $nthreads |
1705 | =item IO::AIO::max_idle $nthreads |
1237 | |
1706 | |
1238 | Limit the number of threads (default: 4) that are allowed to idle (i.e., |
1707 | Limit the number of threads (default: 4) that are allowed to idle |
1239 | threads that did not get a request to process within 10 seconds). That |
1708 | (i.e., threads that did not get a request to process within the idle |
1240 | means if a thread becomes idle while C<$nthreads> other threads are also |
1709 | timeout (default: 10 seconds). That means if a thread becomes idle while |
1241 | idle, it will free its resources and exit. |
1710 | C<$nthreads> other threads are also idle, it will free its resources and |
|
|
1711 | exit. |
1242 | |
1712 | |
1243 | This is useful when you allow a large number of threads (e.g. 100 or 1000) |
1713 | This is useful when you allow a large number of threads (e.g. 100 or 1000) |
1244 | to allow for extremely high load situations, but want to free resources |
1714 | to allow for extremely high load situations, but want to free resources |
1245 | under normal circumstances (1000 threads can easily consume 30MB of RAM). |
1715 | under normal circumstances (1000 threads can easily consume 30MB of RAM). |
1246 | |
1716 | |
1247 | The default is probably ok in most situations, especially if thread |
1717 | The default is probably ok in most situations, especially if thread |
1248 | creation is fast. If thread creation is very slow on your system you might |
1718 | creation is fast. If thread creation is very slow on your system you might |
1249 | want to use larger values. |
1719 | want to use larger values. |
1250 | |
1720 | |
|
|
1721 | =item IO::AIO::idle_timeout $seconds |
|
|
1722 | |
|
|
1723 | Sets the minimum idle timeout (default 10) after which worker threads are |
|
|
1724 | allowed to exit. SEe C<IO::AIO::max_idle>. |
|
|
1725 | |
1251 | =item IO::AIO::max_outstanding $maxreqs |
1726 | =item IO::AIO::max_outstanding $maxreqs |
|
|
1727 | |
|
|
1728 | Sets the maximum number of outstanding requests to C<$nreqs>. If |
|
|
1729 | you do queue up more than this number of requests, the next call to |
|
|
1730 | C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as |
|
|
1731 | C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no |
|
|
1732 | longer exceeded. |
|
|
1733 | |
|
|
1734 | In other words, this setting does not enforce a queue limit, but can be |
|
|
1735 | used to make poll functions block if the limit is exceeded. |
1252 | |
1736 | |
1253 | This is a very bad function to use in interactive programs because it |
1737 | This is a very bad function to use in interactive programs because it |
1254 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
1738 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
1255 | use an C<aio_group> together with a feed callback. |
1739 | use an C<aio_group> together with a feed callback. |
1256 | |
1740 | |
1257 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
1741 | It's main use is in scripts without an event loop - when you want to stat |
1258 | do queue up more than this number of requests, the next call to the |
1742 | a lot of files, you can write somehting like this: |
1259 | C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) |
|
|
1260 | function will block until the limit is no longer exceeded. |
|
|
1261 | |
1743 | |
1262 | The default value is very large, so there is no practical limit on the |
1744 | IO::AIO::max_outstanding 32; |
1263 | number of outstanding requests. |
|
|
1264 | |
1745 | |
1265 | You can still queue as many requests as you want. Therefore, |
1746 | for my $path (...) { |
1266 | C<max_outstanding> is mainly useful in simple scripts (with low values) or |
1747 | aio_stat $path , ...; |
1267 | as a stop gap to shield against fatal memory overflow (with large values). |
1748 | IO::AIO::poll_cb; |
|
|
1749 | } |
|
|
1750 | |
|
|
1751 | IO::AIO::flush; |
|
|
1752 | |
|
|
1753 | The call to C<poll_cb> inside the loop will normally return instantly, but |
|
|
1754 | as soon as more thna C<32> reqeusts are in-flight, it will block until |
|
|
1755 | some requests have been handled. This keeps the loop from pushing a large |
|
|
1756 | number of C<aio_stat> requests onto the queue. |
|
|
1757 | |
|
|
1758 | The default value for C<max_outstanding> is very large, so there is no |
|
|
1759 | practical limit on the number of outstanding requests. |
1268 | |
1760 | |
1269 | =back |
1761 | =back |
1270 | |
1762 | |
1271 | =head3 STATISTICAL INFORMATION |
1763 | =head3 STATISTICAL INFORMATION |
1272 | |
1764 | |
… | |
… | |
1292 | Returns the number of requests currently in the pending state (executed, |
1784 | Returns the number of requests currently in the pending state (executed, |
1293 | but not yet processed by poll_cb). |
1785 | but not yet processed by poll_cb). |
1294 | |
1786 | |
1295 | =back |
1787 | =back |
1296 | |
1788 | |
|
|
1789 | =head3 MISCELLANEOUS FUNCTIONS |
|
|
1790 | |
|
|
1791 | IO::AIO implements some functions that might be useful, but are not |
|
|
1792 | asynchronous. |
|
|
1793 | |
|
|
1794 | =over 4 |
|
|
1795 | |
|
|
1796 | =item IO::AIO::sendfile $ofh, $ifh, $offset, $count |
|
|
1797 | |
|
|
1798 | Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, |
|
|
1799 | but is blocking (this makes most sense if you know the input data is |
|
|
1800 | likely cached already and the output filehandle is set to non-blocking |
|
|
1801 | operations). |
|
|
1802 | |
|
|
1803 | Returns the number of bytes copied, or C<-1> on error. |
|
|
1804 | |
|
|
1805 | =item IO::AIO::fadvise $fh, $offset, $len, $advice |
|
|
1806 | |
|
|
1807 | Simply calls the C<posix_fadvise> function (see its |
|
|
1808 | manpage for details). The following advice constants are |
|
|
1809 | available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, |
|
|
1810 | C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, |
|
|
1811 | C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. |
|
|
1812 | |
|
|
1813 | On systems that do not implement C<posix_fadvise>, this function returns |
|
|
1814 | ENOSYS, otherwise the return value of C<posix_fadvise>. |
|
|
1815 | |
|
|
1816 | =item IO::AIO::madvise $scalar, $offset, $len, $advice |
|
|
1817 | |
|
|
1818 | Simply calls the C<posix_madvise> function (see its |
|
|
1819 | manpage for details). The following advice constants are |
|
|
1820 | available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, |
|
|
1821 | C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. |
|
|
1822 | |
|
|
1823 | On systems that do not implement C<posix_madvise>, this function returns |
|
|
1824 | ENOSYS, otherwise the return value of C<posix_madvise>. |
|
|
1825 | |
|
|
1826 | =item IO::AIO::mprotect $scalar, $offset, $len, $protect |
|
|
1827 | |
|
|
1828 | Simply calls the C<mprotect> function on the preferably AIO::mmap'ed |
|
|
1829 | $scalar (see its manpage for details). The following protect |
|
|
1830 | constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, |
|
|
1831 | C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. |
|
|
1832 | |
|
|
1833 | On systems that do not implement C<mprotect>, this function returns |
|
|
1834 | ENOSYS, otherwise the return value of C<mprotect>. |
|
|
1835 | |
|
|
1836 | =item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] |
|
|
1837 | |
|
|
1838 | Memory-maps a file (or anonymous memory range) and attaches it to the |
|
|
1839 | given C<$scalar>, which will act like a string scalar. |
|
|
1840 | |
|
|
1841 | The only operations allowed on the scalar are C<substr>/C<vec> that don't |
|
|
1842 | change the string length, and most read-only operations such as copying it |
|
|
1843 | or searching it with regexes and so on. |
|
|
1844 | |
|
|
1845 | Anything else is unsafe and will, at best, result in memory leaks. |
|
|
1846 | |
|
|
1847 | The memory map associated with the C<$scalar> is automatically removed |
|
|
1848 | when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or |
|
|
1849 | C<IO::AIO::munmap> functions are called. |
|
|
1850 | |
|
|
1851 | This calls the C<mmap>(2) function internally. See your system's manual |
|
|
1852 | page for details on the C<$length>, C<$prot> and C<$flags> parameters. |
|
|
1853 | |
|
|
1854 | The C<$length> must be larger than zero and smaller than the actual |
|
|
1855 | filesize. |
|
|
1856 | |
|
|
1857 | C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, |
|
|
1858 | C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, |
|
|
1859 | |
|
|
1860 | C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or |
|
|
1861 | C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when |
|
|
1862 | not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> |
|
|
1863 | (which is set to C<MAP_ANON> if your system only provides this |
|
|
1864 | constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, |
|
|
1865 | C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or |
|
|
1866 | C<IO::AIO::MAP_NONBLOCK> |
|
|
1867 | |
|
|
1868 | If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. |
|
|
1869 | |
|
|
1870 | C<$offset> is the offset from the start of the file - it generally must be |
|
|
1871 | a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. |
|
|
1872 | |
|
|
1873 | Example: |
|
|
1874 | |
|
|
1875 | use Digest::MD5; |
|
|
1876 | use IO::AIO; |
|
|
1877 | |
|
|
1878 | open my $fh, "<verybigfile" |
|
|
1879 | or die "$!"; |
|
|
1880 | |
|
|
1881 | IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh |
|
|
1882 | or die "verybigfile: $!"; |
|
|
1883 | |
|
|
1884 | my $fast_md5 = md5 $data; |
|
|
1885 | |
|
|
1886 | =item IO::AIO::munmap $scalar |
|
|
1887 | |
|
|
1888 | Removes a previous mmap and undefines the C<$scalar>. |
|
|
1889 | |
|
|
1890 | =item IO::AIO::munlock $scalar, $offset = 0, $length = undef |
|
|
1891 | |
|
|
1892 | Calls the C<munlock> function, undoing the effects of a previous |
|
|
1893 | C<aio_mlock> call (see its description for details). |
|
|
1894 | |
|
|
1895 | =item IO::AIO::munlockall |
|
|
1896 | |
|
|
1897 | Calls the C<munlockall> function. |
|
|
1898 | |
|
|
1899 | On systems that do not implement C<munlockall>, this function returns |
|
|
1900 | ENOSYS, otherwise the return value of C<munlockall>. |
|
|
1901 | |
|
|
1902 | =back |
|
|
1903 | |
1297 | =cut |
1904 | =cut |
1298 | |
1905 | |
1299 | min_parallel 8; |
1906 | min_parallel 8; |
1300 | |
1907 | |
1301 | END { flush } |
1908 | END { flush } |
1302 | |
1909 | |
1303 | 1; |
1910 | 1; |
1304 | |
1911 | |
|
|
1912 | =head1 EVENT LOOP INTEGRATION |
|
|
1913 | |
|
|
1914 | It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO |
|
|
1915 | automatically into many event loops: |
|
|
1916 | |
|
|
1917 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
|
|
1918 | use AnyEvent::AIO; |
|
|
1919 | |
|
|
1920 | You can also integrate IO::AIO manually into many event loops, here are |
|
|
1921 | some examples of how to do this: |
|
|
1922 | |
|
|
1923 | # EV integration |
|
|
1924 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
|
|
1925 | |
|
|
1926 | # Event integration |
|
|
1927 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
1928 | poll => 'r', |
|
|
1929 | cb => \&IO::AIO::poll_cb); |
|
|
1930 | |
|
|
1931 | # Glib/Gtk2 integration |
|
|
1932 | add_watch Glib::IO IO::AIO::poll_fileno, |
|
|
1933 | in => sub { IO::AIO::poll_cb; 1 }; |
|
|
1934 | |
|
|
1935 | # Tk integration |
|
|
1936 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
|
|
1937 | readable => \&IO::AIO::poll_cb); |
|
|
1938 | |
|
|
1939 | # Danga::Socket integration |
|
|
1940 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
|
|
1941 | \&IO::AIO::poll_cb); |
|
|
1942 | |
1305 | =head2 FORK BEHAVIOUR |
1943 | =head2 FORK BEHAVIOUR |
1306 | |
1944 | |
1307 | This module should do "the right thing" when the process using it forks: |
1945 | Usage of pthreads in a program changes the semantics of fork |
|
|
1946 | considerably. Specifically, only async-safe functions can be called after |
|
|
1947 | fork. Perl doesn't know about this, so in general, you cannot call fork |
|
|
1948 | with defined behaviour in perl if pthreads are involved. IO::AIO uses |
|
|
1949 | pthreads, so this applies, but many other extensions and (for inexplicable |
|
|
1950 | reasons) perl itself often is linked against pthreads, so this limitation |
|
|
1951 | applies to quite a lot of perls. |
1308 | |
1952 | |
1309 | Before the fork, IO::AIO enters a quiescent state where no requests |
1953 | This module no longer tries to fight your OS, or POSIX. That means IO::AIO |
1310 | can be added in other threads and no results will be processed. After |
1954 | only works in the process that loaded it. Forking is fully supported, but |
1311 | the fork the parent simply leaves the quiescent state and continues |
1955 | using IO::AIO in the child is not. |
1312 | request/result processing, while the child frees the request/result queue |
|
|
1313 | (so that the requests started before the fork will only be handled in the |
|
|
1314 | parent). Threads will be started on demand until the limit set in the |
|
|
1315 | parent process has been reached again. |
|
|
1316 | |
1956 | |
1317 | In short: the parent will, after a short pause, continue as if fork had |
1957 | You might get around by not I<using> IO::AIO before (or after) |
1318 | not been called, while the child will act as if IO::AIO has not been used |
1958 | forking. You could also try to call the L<IO::AIO::reinit> function in the |
1319 | yet. |
1959 | child: |
|
|
1960 | |
|
|
1961 | =over 4 |
|
|
1962 | |
|
|
1963 | =item IO::AIO::reinit |
|
|
1964 | |
|
|
1965 | Abandons all current requests and I/O threads and simply reinitialises all |
|
|
1966 | data structures. This is not an operation supported by any standards, but |
|
|
1967 | happens to work on GNU/Linux and some newer BSD systems. |
|
|
1968 | |
|
|
1969 | The only reasonable use for this function is to call it after forking, if |
|
|
1970 | C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in |
|
|
1971 | the process will result in undefined behaviour. Calling it at any time |
|
|
1972 | will also result in any undefined (by POSIX) behaviour. |
|
|
1973 | |
|
|
1974 | =back |
1320 | |
1975 | |
1321 | =head2 MEMORY USAGE |
1976 | =head2 MEMORY USAGE |
1322 | |
1977 | |
1323 | Per-request usage: |
1978 | Per-request usage: |
1324 | |
1979 | |