| … | |
… | |
| 150 | QUICK OVERVIEW |
150 | QUICK OVERVIEW |
| 151 | This section simply lists the prototypes of the most important functions |
151 | This section simply lists the prototypes of the most important functions |
| 152 | for quick reference. See the following sections for function-by-function |
152 | for quick reference. See the following sections for function-by-function |
| 153 | documentation. |
153 | documentation. |
| 154 | |
154 | |
|
|
155 | aio_wd $pathname, $callback->($wd) |
| 155 | aio_open $pathname, $flags, $mode, $callback->($fh) |
156 | aio_open $pathname, $flags, $mode, $callback->($fh) |
| 156 | aio_close $fh, $callback->($status) |
157 | aio_close $fh, $callback->($status) |
| 157 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
158 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
| 158 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
159 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
| 159 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
160 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
| … | |
… | |
| 164 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
165 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
| 165 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
166 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
| 166 | aio_truncate $fh_or_path, $offset, $callback->($status) |
167 | aio_truncate $fh_or_path, $offset, $callback->($status) |
| 167 | aio_chmod $fh_or_path, $mode, $callback->($status) |
168 | aio_chmod $fh_or_path, $mode, $callback->($status) |
| 168 | aio_unlink $pathname, $callback->($status) |
169 | aio_unlink $pathname, $callback->($status) |
| 169 | aio_mknod $path, $mode, $dev, $callback->($status) |
170 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
| 170 | aio_link $srcpath, $dstpath, $callback->($status) |
171 | aio_link $srcpath, $dstpath, $callback->($status) |
| 171 | aio_symlink $srcpath, $dstpath, $callback->($status) |
172 | aio_symlink $srcpath, $dstpath, $callback->($status) |
| 172 | aio_readlink $path, $callback->($link) |
173 | aio_readlink $pathname, $callback->($link) |
|
|
174 | aio_realpath $pathname, $callback->($link) |
| 173 | aio_rename $srcpath, $dstpath, $callback->($status) |
175 | aio_rename $srcpath, $dstpath, $callback->($status) |
| 174 | aio_mkdir $pathname, $mode, $callback->($status) |
176 | aio_mkdir $pathname, $mode, $callback->($status) |
| 175 | aio_rmdir $pathname, $callback->($status) |
177 | aio_rmdir $pathname, $callback->($status) |
| 176 | aio_readdir $pathname, $callback->($entries) |
178 | aio_readdir $pathname, $callback->($entries) |
| 177 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
179 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
| 178 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
180 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
| 179 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
181 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
|
|
182 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
| 180 | aio_load $path, $data, $callback->($status) |
183 | aio_load $pathname, $data, $callback->($status) |
| 181 | aio_copy $srcpath, $dstpath, $callback->($status) |
184 | aio_copy $srcpath, $dstpath, $callback->($status) |
| 182 | aio_move $srcpath, $dstpath, $callback->($status) |
185 | aio_move $srcpath, $dstpath, $callback->($status) |
| 183 | aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
|
|
| 184 | aio_rmtree $path, $callback->($status) |
186 | aio_rmtree $pathname, $callback->($status) |
| 185 | aio_sync $callback->($status) |
187 | aio_sync $callback->($status) |
|
|
188 | aio_syncfs $fh, $callback->($status) |
| 186 | aio_fsync $fh, $callback->($status) |
189 | aio_fsync $fh, $callback->($status) |
| 187 | aio_fdatasync $fh, $callback->($status) |
190 | aio_fdatasync $fh, $callback->($status) |
| 188 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
191 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
| 189 | aio_pathsync $path, $callback->($status) |
192 | aio_pathsync $pathname, $callback->($status) |
| 190 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
193 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
| 191 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
194 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
| 192 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
195 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
| 193 | aio_mlockall $flags, $callback->($status) |
196 | aio_mlockall $flags, $callback->($status) |
| 194 | aio_group $callback->(...) |
197 | aio_group $callback->(...) |
| … | |
… | |
| 221 | |
224 | |
| 222 | AIO REQUEST FUNCTIONS |
225 | AIO REQUEST FUNCTIONS |
| 223 | All the "aio_*" calls are more or less thin wrappers around the syscall |
226 | All the "aio_*" calls are more or less thin wrappers around the syscall |
| 224 | with the same name (sans "aio_"). The arguments are similar or |
227 | with the same name (sans "aio_"). The arguments are similar or |
| 225 | identical, and they all accept an additional (and optional) $callback |
228 | identical, and they all accept an additional (and optional) $callback |
| 226 | argument which must be a code reference. This code reference will get |
229 | argument which must be a code reference. This code reference will be |
| 227 | called with the syscall return code (e.g. most syscalls return -1 on |
|
|
| 228 | error, unlike perl, which usually delivers "false") as its sole argument |
|
|
| 229 | after the given syscall has been executed asynchronously. |
230 | called after the syscall has been executed in an asynchronous fashion. |
|
|
231 | The results of the request will be passed as arguments to the callback |
|
|
232 | (and, if an error occured, in $!) - for most requests the syscall return |
|
|
233 | code (e.g. most syscalls return -1 on error, unlike perl, which usually |
|
|
234 | delivers "false"). |
|
|
235 | |
|
|
236 | Some requests (such as "aio_readdir") pass the actual results and |
|
|
237 | communicate failures by passing "undef". |
| 230 | |
238 | |
| 231 | All functions expecting a filehandle keep a copy of the filehandle |
239 | All functions expecting a filehandle keep a copy of the filehandle |
| 232 | internally until the request has finished. |
240 | internally until the request has finished. |
| 233 | |
241 | |
| 234 | All functions return request objects of type IO::AIO::REQ that allow |
242 | All functions return request objects of type IO::AIO::REQ that allow |
| 235 | further manipulation of those requests while they are in-flight. |
243 | further manipulation of those requests while they are in-flight. |
| 236 | |
244 | |
| 237 | The pathnames you pass to these routines *must* be absolute and encoded |
245 | The pathnames you pass to these routines *should* be absolute. The |
| 238 | as octets. The reason for the former is that at the time the request is |
246 | reason for this is that at the time the request is being executed, the |
| 239 | being executed, the current working directory could have changed. |
247 | current working directory could have changed. Alternatively, you can |
| 240 | Alternatively, you can make sure that you never change the current |
248 | make sure that you never change the current working directory anywhere |
| 241 | working directory anywhere in the program and then use relative paths. |
249 | in the program and then use relative paths. You can also take advantage |
|
|
250 | of IO::AIOs working directory abstraction, that lets you specify paths |
|
|
251 | relative to some previously-opened "working directory object" - see the |
|
|
252 | description of the "IO::AIO::WD" class later in this document. |
| 242 | |
253 | |
| 243 | To encode pathnames as octets, either make sure you either: a) always |
254 | To encode pathnames as octets, either make sure you either: a) always |
| 244 | pass in filenames you got from outside (command line, readdir etc.) |
255 | pass in filenames you got from outside (command line, readdir etc.) |
| 245 | without tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module |
256 | without tinkering, b) are in your native filesystem encoding, c) use the |
| 246 | and encode your pathnames to the locale (or other) encoding in effect in |
257 | Encode module and encode your pathnames to the locale (or other) |
| 247 | the user environment, d) use Glib::filename_from_unicode on unicode |
258 | encoding in effect in the user environment, d) use |
| 248 | filenames or e) use something else to ensure your scalar has the correct |
259 | Glib::filename_from_unicode on unicode filenames or e) use something |
| 249 | contents. |
260 | else to ensure your scalar has the correct contents. |
| 250 | |
261 | |
| 251 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
262 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
| 252 | handles correctly whether it is set or not. |
263 | handles correctly whether it is set or not. |
| 253 | |
264 | |
| 254 | $prev_pri = aioreq_pri [$pri] |
265 | $prev_pri = aioreq_pri [$pri] |
| … | |
… | |
| 531 | |
542 | |
| 532 | aio_unlink $pathname, $callback->($status) |
543 | aio_unlink $pathname, $callback->($status) |
| 533 | Asynchronously unlink (delete) a file and call the callback with the |
544 | Asynchronously unlink (delete) a file and call the callback with the |
| 534 | result code. |
545 | result code. |
| 535 | |
546 | |
| 536 | aio_mknod $path, $mode, $dev, $callback->($status) |
547 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
| 537 | [EXPERIMENTAL] |
548 | [EXPERIMENTAL] |
| 538 | |
549 | |
| 539 | Asynchronously create a device node (or fifo). See mknod(2). |
550 | Asynchronously create a device node (or fifo). See mknod(2). |
| 540 | |
551 | |
| 541 | The only (POSIX-) portable way of calling this function is: |
552 | The only (POSIX-) portable way of calling this function is: |
| 542 | |
553 | |
| 543 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
554 | aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
| 544 | |
555 | |
| 545 | See "aio_stat" for info about some potentially helpful extra |
556 | See "aio_stat" for info about some potentially helpful extra |
| 546 | constants and functions. |
557 | constants and functions. |
| 547 | |
558 | |
| 548 | aio_link $srcpath, $dstpath, $callback->($status) |
559 | aio_link $srcpath, $dstpath, $callback->($status) |
| … | |
… | |
| 552 | aio_symlink $srcpath, $dstpath, $callback->($status) |
563 | aio_symlink $srcpath, $dstpath, $callback->($status) |
| 553 | Asynchronously create a new symbolic link to the existing object at |
564 | Asynchronously create a new symbolic link to the existing object at |
| 554 | $srcpath at the path $dstpath and call the callback with the result |
565 | $srcpath at the path $dstpath and call the callback with the result |
| 555 | code. |
566 | code. |
| 556 | |
567 | |
| 557 | aio_readlink $path, $callback->($link) |
568 | aio_readlink $pathname, $callback->($link) |
| 558 | Asynchronously read the symlink specified by $path and pass it to |
569 | Asynchronously read the symlink specified by $path and pass it to |
| 559 | the callback. If an error occurs, nothing or undef gets passed to |
570 | the callback. If an error occurs, nothing or undef gets passed to |
| 560 | the callback. |
571 | the callback. |
|
|
572 | |
|
|
573 | aio_realpath $pathname, $callback->($path) |
|
|
574 | Asynchronously make the path absolute and resolve any symlinks in |
|
|
575 | $path. The resulting path only consists of directories (Same as |
|
|
576 | Cwd::realpath). |
|
|
577 | |
|
|
578 | This request can be used to get the absolute path of the current |
|
|
579 | working directory by passing it a path of . (a single dot). |
| 561 | |
580 | |
| 562 | aio_rename $srcpath, $dstpath, $callback->($status) |
581 | aio_rename $srcpath, $dstpath, $callback->($status) |
| 563 | Asynchronously rename the object at $srcpath to $dstpath, just as |
582 | Asynchronously rename the object at $srcpath to $dstpath, just as |
| 564 | rename(2) and call the callback with the result code. |
583 | rename(2) and call the callback with the result code. |
| 565 | |
584 | |
| … | |
… | |
| 579 | |
598 | |
| 580 | The callback is passed a single argument which is either "undef" or |
599 | The callback is passed a single argument which is either "undef" or |
| 581 | an array-ref with the filenames. |
600 | an array-ref with the filenames. |
| 582 | |
601 | |
| 583 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
602 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
| 584 | Quite similar to "aio_readdir", but the $flags argument allows to |
603 | Quite similar to "aio_readdir", but the $flags argument allows one |
| 585 | tune behaviour and output format. In case of an error, $entries will |
604 | to tune behaviour and output format. In case of an error, $entries |
| 586 | be "undef". |
605 | will be "undef". |
| 587 | |
606 | |
| 588 | The flags are a combination of the following constants, ORed |
607 | The flags are a combination of the following constants, ORed |
| 589 | together (the flags will also be passed to the callback, possibly |
608 | together (the flags will also be passed to the callback, possibly |
| 590 | modified): |
609 | modified): |
| 591 | |
610 | |
| … | |
… | |
| 636 | optimal stat order. |
655 | optimal stat order. |
| 637 | |
656 | |
| 638 | IO::AIO::READDIR_FOUND_UNKNOWN |
657 | IO::AIO::READDIR_FOUND_UNKNOWN |
| 639 | This flag should not be set when calling "aio_readdirx". |
658 | This flag should not be set when calling "aio_readdirx". |
| 640 | Instead, it is being set by "aio_readdirx", when any of the |
659 | Instead, it is being set by "aio_readdirx", when any of the |
| 641 | $type's found were "IO::AIO::DT_UNKNOWN". The absense of this |
660 | $type's found were "IO::AIO::DT_UNKNOWN". The absence of this |
| 642 | flag therefore indicates that all $type's are known, which can |
661 | flag therefore indicates that all $type's are known, which can |
| 643 | be used to speed up some algorithms. |
662 | be used to speed up some algorithms. |
| 644 | |
663 | |
| 645 | aio_load $path, $data, $callback->($status) |
664 | aio_load $pathname, $data, $callback->($status) |
| 646 | This is a composite request that tries to fully load the given file |
665 | This is a composite request that tries to fully load the given file |
| 647 | into memory. Status is the same as with aio_read. |
666 | into memory. Status is the same as with aio_read. |
| 648 | |
667 | |
| 649 | aio_copy $srcpath, $dstpath, $callback->($status) |
668 | aio_copy $srcpath, $dstpath, $callback->($status) |
| 650 | Try to copy the *file* (directories not supported as either source |
669 | Try to copy the *file* (directories not supported as either source |
| … | |
… | |
| 667 | |
686 | |
| 668 | This is a composite request that tries to rename(2) the file first; |
687 | This is a composite request that tries to rename(2) the file first; |
| 669 | if rename fails with "EXDEV", it copies the file with "aio_copy" |
688 | if rename fails with "EXDEV", it copies the file with "aio_copy" |
| 670 | and, if that is successful, unlinks the $srcpath. |
689 | and, if that is successful, unlinks the $srcpath. |
| 671 | |
690 | |
| 672 | aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
691 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
| 673 | Scans a directory (similar to "aio_readdir") but additionally tries |
692 | Scans a directory (similar to "aio_readdir") but additionally tries |
| 674 | to efficiently separate the entries of directory $path into two sets |
693 | to efficiently separate the entries of directory $path into two sets |
| 675 | of names, directories you can recurse into (directories), and ones |
694 | of names, directories you can recurse into (directories), and ones |
| 676 | you cannot recurse into (everything else, including symlinks to |
695 | you cannot recurse into (everything else, including symlinks to |
| 677 | directories). |
696 | directories). |
| … | |
… | |
| 710 | Then entries will be sorted into likely directories a non-initial |
729 | Then entries will be sorted into likely directories a non-initial |
| 711 | dot currently) and likely non-directories (see "aio_readdirx"). Then |
730 | dot currently) and likely non-directories (see "aio_readdirx"). Then |
| 712 | every entry plus an appended "/." will be "stat"'ed, likely |
731 | every entry plus an appended "/." will be "stat"'ed, likely |
| 713 | directories first, in order of their inode numbers. If that |
732 | directories first, in order of their inode numbers. If that |
| 714 | succeeds, it assumes that the entry is a directory or a symlink to |
733 | succeeds, it assumes that the entry is a directory or a symlink to |
| 715 | directory (which will be checked seperately). This is often faster |
734 | directory (which will be checked separately). This is often faster |
| 716 | than stat'ing the entry itself because filesystems might detect the |
735 | than stat'ing the entry itself because filesystems might detect the |
| 717 | type of the entry without reading the inode data (e.g. ext2fs |
736 | type of the entry without reading the inode data (e.g. ext2fs |
| 718 | filetype feature), even on systems that cannot return the filetype |
737 | filetype feature), even on systems that cannot return the filetype |
| 719 | information on readdir. |
738 | information on readdir. |
| 720 | |
739 | |
| … | |
… | |
| 726 | |
745 | |
| 727 | It will also likely work on non-POSIX filesystems with reduced |
746 | It will also likely work on non-POSIX filesystems with reduced |
| 728 | efficiency as those tend to return 0 or 1 as link counts, which |
747 | efficiency as those tend to return 0 or 1 as link counts, which |
| 729 | disables the directory counting heuristic. |
748 | disables the directory counting heuristic. |
| 730 | |
749 | |
| 731 | aio_rmtree $path, $callback->($status) |
750 | aio_rmtree $pathname, $callback->($status) |
| 732 | Delete a directory tree starting (and including) $path, return the |
751 | Delete a directory tree starting (and including) $path, return the |
| 733 | status of the final "rmdir" only. This is a composite request that |
752 | status of the final "rmdir" only. This is a composite request that |
| 734 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
753 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
| 735 | everything else. |
754 | everything else. |
| 736 | |
755 | |
| … | |
… | |
| 745 | Asynchronously call fdatasync on the given filehandle and call the |
764 | Asynchronously call fdatasync on the given filehandle and call the |
| 746 | callback with the fdatasync result code. |
765 | callback with the fdatasync result code. |
| 747 | |
766 | |
| 748 | If this call isn't available because your OS lacks it or it couldn't |
767 | If this call isn't available because your OS lacks it or it couldn't |
| 749 | be detected, it will be emulated by calling "fsync" instead. |
768 | be detected, it will be emulated by calling "fsync" instead. |
|
|
769 | |
|
|
770 | aio_syncfs $fh, $callback->($status) |
|
|
771 | Asynchronously call the syncfs syscall to sync the filesystem |
|
|
772 | associated to the given filehandle and call the callback with the |
|
|
773 | syncfs result code. If syncfs is not available, calls sync(), but |
|
|
774 | returns -1 and sets errno to "ENOSYS" nevertheless. |
| 750 | |
775 | |
| 751 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
776 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
| 752 | Sync the data portion of the file specified by $offset and $length |
777 | Sync the data portion of the file specified by $offset and $length |
| 753 | to disk (but NOT the metadata), by calling the Linux-specific |
778 | to disk (but NOT the metadata), by calling the Linux-specific |
| 754 | sync_file_range call. If sync_file_range is not available or it |
779 | sync_file_range call. If sync_file_range is not available or it |
| … | |
… | |
| 758 | "IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE", |
783 | "IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE", |
| 759 | "IO::AIO::SYNC_FILE_RANGE_WRITE" and |
784 | "IO::AIO::SYNC_FILE_RANGE_WRITE" and |
| 760 | "IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range |
785 | "IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range |
| 761 | manpage for details. |
786 | manpage for details. |
| 762 | |
787 | |
| 763 | aio_pathsync $path, $callback->($status) |
788 | aio_pathsync $pathname, $callback->($status) |
| 764 | This request tries to open, fsync and close the given path. This is |
789 | This request tries to open, fsync and close the given path. This is |
| 765 | a composite request intended to sync directories after directory |
790 | a composite request intended to sync directories after directory |
| 766 | operations (E.g. rename). This might not work on all operating |
791 | operations (E.g. rename). This might not work on all operating |
| 767 | systems or have any specific effect, but usually it makes sure that |
792 | systems or have any specific effect, but usually it makes sure that |
| 768 | directory changes get written to disc. It works for anything that |
793 | directory changes get written to disc. It works for anything that |
| … | |
… | |
| 881 | requests like sleep and file handle readable/writable, the overhead |
906 | requests like sleep and file handle readable/writable, the overhead |
| 882 | this creates is immense (it blocks a thread for a long time) so do |
907 | this creates is immense (it blocks a thread for a long time) so do |
| 883 | not use this function except to put your application under |
908 | not use this function except to put your application under |
| 884 | artificial I/O pressure. |
909 | artificial I/O pressure. |
| 885 | |
910 | |
|
|
911 | IO::AIO::WD - multiple working directories |
|
|
912 | Your process only has one current working directory, which is used by |
|
|
913 | all threads. This makes it hard to use relative paths (some other |
|
|
914 | component could call "chdir" at any time, and it is hard to control when |
|
|
915 | the path will be used by IO::AIO). |
|
|
916 | |
|
|
917 | One solution for this is to always use absolute paths. This usually |
|
|
918 | works, but can be quite slow (the kernel has to walk the whole path on |
|
|
919 | every access), and can also be a hassle to implement. |
|
|
920 | |
|
|
921 | Newer POSIX systems have a number of functions (openat, fdopendir, |
|
|
922 | futimensat and so on) that make it possible to specify working |
|
|
923 | directories per operation. |
|
|
924 | |
|
|
925 | For portability, and because the clowns who "designed", or shall I |
|
|
926 | write, perpetrated this new interface were obviously half-drunk, this |
|
|
927 | abstraction cannot be perfect, though. |
|
|
928 | |
|
|
929 | IO::AIO allows you to convert directory paths into a so-called |
|
|
930 | IO::AIO::WD object. This object stores the canonicalised, absolute |
|
|
931 | version of the path, and on systems that allow it, also a directory file |
|
|
932 | descriptor. |
|
|
933 | |
|
|
934 | Everywhere where a pathname is accepted by IO::AIO (e.g. in "aio_stat" |
|
|
935 | or "aio_unlink"), one can specify an array reference with an IO::AIO::WD |
|
|
936 | object and a pathname instead (or the IO::AIO::WD object alone, which |
|
|
937 | gets interpreted as "[$wd, "."]"). If the pathname is absolute, the |
|
|
938 | IO::AIO::WD object is ignored, otherwise the pathname is resolved |
|
|
939 | relative to that IO::AIO::WD object. |
|
|
940 | |
|
|
941 | For example, to get a wd object for /etc and then stat passwd inside, |
|
|
942 | you would write: |
|
|
943 | |
|
|
944 | aio_wd "/etc", sub { |
|
|
945 | my $etcdir = shift; |
|
|
946 | |
|
|
947 | # although $etcdir can be undef on error, there is generally no reason |
|
|
948 | # to check for errors here, as aio_stat will fail with ENOENT |
|
|
949 | # when $etcdir is undef. |
|
|
950 | |
|
|
951 | aio_stat [$etcdir, "passwd"], sub { |
|
|
952 | # yay |
|
|
953 | }; |
|
|
954 | }; |
|
|
955 | |
|
|
956 | That "aio_wd" is a request and not a normal function shows that creating |
|
|
957 | an IO::AIO::WD object is itself a potentially blocking operation, which |
|
|
958 | is why it is done asynchronously. |
|
|
959 | |
|
|
960 | To stat the directory obtained with "aio_wd" above, one could write |
|
|
961 | either of the following three request calls: |
|
|
962 | |
|
|
963 | aio_lstat "/etc" , sub { ... # pathname as normal string |
|
|
964 | aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself) |
|
|
965 | aio_lstat $wd , sub { ... # shorthand for the previous |
|
|
966 | |
|
|
967 | As with normal pathnames, IO::AIO keeps a copy of the working directory |
|
|
968 | object and the pathname string, so you could write the following without |
|
|
969 | causing any issues due to $path getting reused: |
|
|
970 | |
|
|
971 | my $path = [$wd, undef]; |
|
|
972 | |
|
|
973 | for my $name (qw(abc def ghi)) { |
|
|
974 | $path->[1] = $name; |
|
|
975 | aio_stat $path, sub { |
|
|
976 | # ... |
|
|
977 | }; |
|
|
978 | } |
|
|
979 | |
|
|
980 | There are some caveats: when directories get renamed (or deleted), the |
|
|
981 | pathname string doesn't change, so will point to the new directory (or |
|
|
982 | nowhere at all), while the directory fd, if available on the system, |
|
|
983 | will still point to the original directory. Most functions accepting a |
|
|
984 | pathname will use the directory fd on newer systems, and the string on |
|
|
985 | older systems. Some functions (such as realpath) will always rely on the |
|
|
986 | string form of the pathname. |
|
|
987 | |
|
|
988 | So this fucntionality is mainly useful to get some protection against |
|
|
989 | "chdir", to easily get an absolute path out of a relative path for |
|
|
990 | future reference, and to speed up doing many operations in the same |
|
|
991 | directory (e.g. when stat'ing all files in a directory). |
|
|
992 | |
|
|
993 | The following functions implement this working directory abstraction: |
|
|
994 | |
|
|
995 | aio_wd $pathname, $callback->($wd) |
|
|
996 | Asynchonously canonicalise the given pathname and convert it to an |
|
|
997 | IO::AIO::WD object representing it. If possible and supported on the |
|
|
998 | system, also open a directory fd to speed up pathname resolution |
|
|
999 | relative to this working directory. |
|
|
1000 | |
|
|
1001 | If something goes wrong, then "undef" is passwd to the callback |
|
|
1002 | instead of a working directory object and $! is set appropriately. |
|
|
1003 | Since passing "undef" as working directory component of a pathname |
|
|
1004 | fails the request with "ENOENT", there is often no need for error |
|
|
1005 | checking in the "aio_wd" callback, as future requests using the |
|
|
1006 | value will fail in the expected way. |
|
|
1007 | |
|
|
1008 | If this call isn't available because your OS lacks it or it couldn't |
|
|
1009 | be detected, it will be emulated by calling "fsync" instead. |
|
|
1010 | |
|
|
1011 | IO::AIO::CWD |
|
|
1012 | This is a compiletime constant (object) that represents the process |
|
|
1013 | current working directory. |
|
|
1014 | |
|
|
1015 | Specifying this object as working directory object for a pathname is |
|
|
1016 | as if the pathname would be specified directly, without a directory |
|
|
1017 | object, e.g., these calls are functionally identical: |
|
|
1018 | |
|
|
1019 | aio_stat "somefile", sub { ... }; |
|
|
1020 | aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; |
|
|
1021 | |
| 886 | IO::AIO::REQ CLASS |
1022 | IO::AIO::REQ CLASS |
| 887 | All non-aggregate "aio_*" functions return an object of this class when |
1023 | All non-aggregate "aio_*" functions return an object of this class when |
| 888 | called in non-void context. |
1024 | called in non-void context. |
| 889 | |
1025 | |
| 890 | cancel $req |
1026 | cancel $req |
| … | |
… | |
| 989 | Sets a feeder/generator on this group: every group can have an |
1125 | Sets a feeder/generator on this group: every group can have an |
| 990 | attached generator that generates requests if idle. The idea behind |
1126 | attached generator that generates requests if idle. The idea behind |
| 991 | this is that, although you could just queue as many requests as you |
1127 | this is that, although you could just queue as many requests as you |
| 992 | want in a group, this might starve other requests for a potentially |
1128 | want in a group, this might starve other requests for a potentially |
| 993 | long time. For example, "aio_scandir" might generate hundreds of |
1129 | long time. For example, "aio_scandir" might generate hundreds of |
| 994 | thousands "aio_stat" requests, delaying any later requests for a |
1130 | thousands of "aio_stat" requests, delaying any later requests for a |
| 995 | long time. |
1131 | long time. |
| 996 | |
1132 | |
| 997 | To avoid this, and allow incremental generation of requests, you can |
1133 | To avoid this, and allow incremental generation of requests, you can |
| 998 | instead a group and set a feeder on it that generates those |
1134 | instead a group and set a feeder on it that generates those |
| 999 | requests. The feed callback will be called whenever there are few |
1135 | requests. The feed callback will be called whenever there are few |
| … | |
… | |
| 1247 | |
1383 | |
| 1248 | Returns the number of bytes copied, or -1 on error. |
1384 | Returns the number of bytes copied, or -1 on error. |
| 1249 | |
1385 | |
| 1250 | IO::AIO::fadvise $fh, $offset, $len, $advice |
1386 | IO::AIO::fadvise $fh, $offset, $len, $advice |
| 1251 | Simply calls the "posix_fadvise" function (see its manpage for |
1387 | Simply calls the "posix_fadvise" function (see its manpage for |
| 1252 | details). The following advice constants are avaiable: |
1388 | details). The following advice constants are available: |
| 1253 | "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", |
1389 | "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", |
| 1254 | "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", |
1390 | "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", |
| 1255 | "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". |
1391 | "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". |
| 1256 | |
1392 | |
| 1257 | On systems that do not implement "posix_fadvise", this function |
1393 | On systems that do not implement "posix_fadvise", this function |
| 1258 | returns ENOSYS, otherwise the return value of "posix_fadvise". |
1394 | returns ENOSYS, otherwise the return value of "posix_fadvise". |
| 1259 | |
1395 | |
| 1260 | IO::AIO::madvise $scalar, $offset, $len, $advice |
1396 | IO::AIO::madvise $scalar, $offset, $len, $advice |
| 1261 | Simply calls the "posix_madvise" function (see its manpage for |
1397 | Simply calls the "posix_madvise" function (see its manpage for |
| 1262 | details). The following advice constants are avaiable: |
1398 | details). The following advice constants are available: |
| 1263 | "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", |
1399 | "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", |
| 1264 | "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", |
1400 | "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", |
| 1265 | "IO::AIO::MADV_DONTNEED". |
1401 | "IO::AIO::MADV_DONTNEED". |
| 1266 | |
1402 | |
| 1267 | On systems that do not implement "posix_madvise", this function |
1403 | On systems that do not implement "posix_madvise", this function |
| 1268 | returns ENOSYS, otherwise the return value of "posix_madvise". |
1404 | returns ENOSYS, otherwise the return value of "posix_madvise". |
| 1269 | |
1405 | |
| 1270 | IO::AIO::mprotect $scalar, $offset, $len, $protect |
1406 | IO::AIO::mprotect $scalar, $offset, $len, $protect |
| 1271 | Simply calls the "mprotect" function on the preferably AIO::mmap'ed |
1407 | Simply calls the "mprotect" function on the preferably AIO::mmap'ed |
| 1272 | $scalar (see its manpage for details). The following protect |
1408 | $scalar (see its manpage for details). The following protect |
| 1273 | constants are avaiable: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", |
1409 | constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", |
| 1274 | "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". |
1410 | "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". |
| 1275 | |
1411 | |
| 1276 | On systems that do not implement "mprotect", this function returns |
1412 | On systems that do not implement "mprotect", this function returns |
| 1277 | ENOSYS, otherwise the return value of "mprotect". |
1413 | ENOSYS, otherwise the return value of "mprotect". |
| 1278 | |
1414 | |
| … | |
… | |
| 1371 | |
1507 | |
| 1372 | FORK BEHAVIOUR |
1508 | FORK BEHAVIOUR |
| 1373 | Usage of pthreads in a program changes the semantics of fork |
1509 | Usage of pthreads in a program changes the semantics of fork |
| 1374 | considerably. Specifically, only async-safe functions can be called |
1510 | considerably. Specifically, only async-safe functions can be called |
| 1375 | after fork. Perl doesn't know about this, so in general, you cannot call |
1511 | after fork. Perl doesn't know about this, so in general, you cannot call |
| 1376 | fork with defined behaviour in perl. IO::AIO uses pthreads, so this |
1512 | fork with defined behaviour in perl if pthreads are involved. IO::AIO |
| 1377 | applies, but many other extensions and (for inexplicable reasons) perl |
1513 | uses pthreads, so this applies, but many other extensions and (for |
| 1378 | itself often is linked against pthreads, so this limitation applies. |
1514 | inexplicable reasons) perl itself often is linked against pthreads, so |
|
|
1515 | this limitation applies to quite a lot of perls. |
| 1379 | |
1516 | |
| 1380 | Some operating systems have extensions that allow safe use of fork, and |
1517 | This module no longer tries to fight your OS, or POSIX. That means |
| 1381 | this module should do "the right thing" on those, and tries on others. |
1518 | IO::AIO only works in the process that loaded it. Forking is fully |
| 1382 | At the time of this writing (2011) only GNU/Linux supports these |
1519 | supported, but using IO::AIO in the child is not. |
| 1383 | extensions to POSIX. |
1520 | |
|
|
1521 | You might get around by not *using* IO::AIO before (or after) forking. |
|
|
1522 | You could also try to call the IO::AIO::reinit function in the child: |
|
|
1523 | |
|
|
1524 | IO::AIO::reinit |
|
|
1525 | Abandons all current requests and I/O threads and simply |
|
|
1526 | reinitialises all data structures. This is not an operation |
|
|
1527 | supported by any standards, but happens to work on GNU/Linux and |
|
|
1528 | some newer BSD systems. |
|
|
1529 | |
|
|
1530 | The only reasonable use for this function is to call it after |
|
|
1531 | forking, if "IO::AIO" was used in the parent. Calling it while |
|
|
1532 | IO::AIO is active in the process will result in undefined behaviour. |
|
|
1533 | Calling it at any time will also result in any undefined (by POSIX) |
|
|
1534 | behaviour. |
| 1384 | |
1535 | |
| 1385 | MEMORY USAGE |
1536 | MEMORY USAGE |
| 1386 | Per-request usage: |
1537 | Per-request usage: |
| 1387 | |
1538 | |
| 1388 | Each aio request uses - depending on your architecture - around 100-200 |
1539 | Each aio request uses - depending on your architecture - around 100-200 |
