… | |
… | |
736 | =item bool ev_is_pending (ev_TYPE *watcher) |
736 | =item bool ev_is_pending (ev_TYPE *watcher) |
737 | |
737 | |
738 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
738 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
739 | events but its callback has not yet been invoked). As long as a watcher |
739 | events but its callback has not yet been invoked). As long as a watcher |
740 | is pending (but not active) you must not call an init function on it (but |
740 | is pending (but not active) you must not call an init function on it (but |
741 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
741 | C<ev_TYPE_set> is safe), you must not change its priority, and you must |
742 | libev (e.g. you cnanot C<free ()> it). |
742 | make sure the watcher is available to libev (e.g. you cannot C<free ()> |
|
|
743 | it). |
743 | |
744 | |
744 | =item callback ev_cb (ev_TYPE *watcher) |
745 | =item callback ev_cb (ev_TYPE *watcher) |
745 | |
746 | |
746 | Returns the callback currently set on the watcher. |
747 | Returns the callback currently set on the watcher. |
747 | |
748 | |
… | |
… | |
766 | watchers on the same event and make sure one is called first. |
767 | watchers on the same event and make sure one is called first. |
767 | |
768 | |
768 | If you need to suppress invocation when higher priority events are pending |
769 | If you need to suppress invocation when higher priority events are pending |
769 | you need to look at C<ev_idle> watchers, which provide this functionality. |
770 | you need to look at C<ev_idle> watchers, which provide this functionality. |
770 | |
771 | |
|
|
772 | You I<must not> change the priority of a watcher as long as it is active or |
|
|
773 | pending. |
|
|
774 | |
771 | The default priority used by watchers when no priority has been set is |
775 | The default priority used by watchers when no priority has been set is |
772 | always C<0>, which is supposed to not be too high and not be too low :). |
776 | always C<0>, which is supposed to not be too high and not be too low :). |
773 | |
777 | |
774 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
778 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
775 | fine, as long as you do not mind that the priority value you query might |
779 | fine, as long as you do not mind that the priority value you query might |
776 | or might not have been adjusted to be within valid range. |
780 | or might not have been adjusted to be within valid range. |
|
|
781 | |
|
|
782 | =item ev_invoke (loop, ev_TYPE *watcher, int revents) |
|
|
783 | |
|
|
784 | Invoke the C<watcher> with the given C<loop> and C<revents>. Neither |
|
|
785 | C<loop> nor C<revents> need to be valid as long as the watcher callback |
|
|
786 | can deal with that fact. |
|
|
787 | |
|
|
788 | =item int ev_clear_pending (loop, ev_TYPE *watcher) |
|
|
789 | |
|
|
790 | If the watcher is pending, this function returns clears its pending status |
|
|
791 | and returns its C<revents> bitset (as if its callback was invoked). If the |
|
|
792 | watcher isn't pending it does nothing and returns C<0>. |
777 | |
793 | |
778 | =back |
794 | =back |
779 | |
795 | |
780 | |
796 | |
781 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
797 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
… | |
… | |
1477 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1493 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1478 | macros, but using them is utterly, utterly and completely pointless. |
1494 | macros, but using them is utterly, utterly and completely pointless. |
1479 | |
1495 | |
1480 | =back |
1496 | =back |
1481 | |
1497 | |
1482 | Example: To include a library such as adns, you would add IO watchers |
1498 | There are a number of principal ways to embed other event loops or modules |
1483 | and a timeout watcher in a prepare handler, as required by libadns, and |
1499 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1500 | (there is a Perl module named C<EV::ADNS> that does this, which you could |
|
|
1501 | use for an actually working example. Another Perl module named C<EV::Glib> |
|
|
1502 | embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV |
|
|
1503 | into the Glib event loop). |
|
|
1504 | |
|
|
1505 | Method 1: Add IO watchers and a timeout watcher in a prepare handler, |
1484 | in a check watcher, destroy them and call into libadns. What follows is |
1506 | and in a check watcher, destroy them and call into libadns. What follows |
1485 | pseudo-code only of course: |
1507 | is pseudo-code only of course. This requires you to either use a low |
|
|
1508 | priority for the check watcher or use C<ev_clear_pending> explicitly, as |
|
|
1509 | the callbacks for the IO/timeout watchers might not have been called yet. |
1486 | |
1510 | |
1487 | static ev_io iow [nfd]; |
1511 | static ev_io iow [nfd]; |
1488 | static ev_timer tw; |
1512 | static ev_timer tw; |
1489 | |
1513 | |
1490 | static void |
1514 | static void |
1491 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1515 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1492 | { |
1516 | { |
1493 | // set the relevant poll flags |
|
|
1494 | // could also call adns_processreadable etc. here |
|
|
1495 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1496 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1497 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1498 | } |
1517 | } |
1499 | |
1518 | |
1500 | // create io watchers for each fd and a timer before blocking |
1519 | // create io watchers for each fd and a timer before blocking |
1501 | static void |
1520 | static void |
1502 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1521 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
… | |
… | |
1508 | |
1527 | |
1509 | /* the callback is illegal, but won't be called as we stop during check */ |
1528 | /* the callback is illegal, but won't be called as we stop during check */ |
1510 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1529 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1511 | ev_timer_start (loop, &tw); |
1530 | ev_timer_start (loop, &tw); |
1512 | |
1531 | |
1513 | // create on ev_io per pollfd |
1532 | // create one ev_io per pollfd |
1514 | for (int i = 0; i < nfd; ++i) |
1533 | for (int i = 0; i < nfd; ++i) |
1515 | { |
1534 | { |
1516 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1535 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1517 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1536 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1518 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1537 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1519 | |
1538 | |
1520 | fds [i].revents = 0; |
1539 | fds [i].revents = 0; |
1521 | iow [i].data = fds + i; |
|
|
1522 | ev_io_start (loop, iow + i); |
1540 | ev_io_start (loop, iow + i); |
1523 | } |
1541 | } |
1524 | } |
1542 | } |
1525 | |
1543 | |
1526 | // stop all watchers after blocking |
1544 | // stop all watchers after blocking |
… | |
… | |
1528 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1546 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1529 | { |
1547 | { |
1530 | ev_timer_stop (loop, &tw); |
1548 | ev_timer_stop (loop, &tw); |
1531 | |
1549 | |
1532 | for (int i = 0; i < nfd; ++i) |
1550 | for (int i = 0; i < nfd; ++i) |
|
|
1551 | { |
|
|
1552 | // set the relevant poll flags |
|
|
1553 | // could also call adns_processreadable etc. here |
|
|
1554 | struct pollfd *fd = fds + i; |
|
|
1555 | int revents = ev_clear_pending (iow + i); |
|
|
1556 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1557 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1558 | |
|
|
1559 | // now stop the watcher |
1533 | ev_io_stop (loop, iow + i); |
1560 | ev_io_stop (loop, iow + i); |
|
|
1561 | } |
1534 | |
1562 | |
1535 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1563 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1564 | } |
|
|
1565 | |
|
|
1566 | Method 2: This would be just like method 1, but you run C<adns_afterpoll> |
|
|
1567 | in the prepare watcher and would dispose of the check watcher. |
|
|
1568 | |
|
|
1569 | Method 3: If the module to be embedded supports explicit event |
|
|
1570 | notification (adns does), you can also make use of the actual watcher |
|
|
1571 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1572 | |
|
|
1573 | static void |
|
|
1574 | timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1575 | { |
|
|
1576 | adns_state ads = (adns_state)w->data; |
|
|
1577 | update_now (EV_A); |
|
|
1578 | |
|
|
1579 | adns_processtimeouts (ads, &tv_now); |
|
|
1580 | } |
|
|
1581 | |
|
|
1582 | static void |
|
|
1583 | io_cb (EV_P_ ev_io *w, int revents) |
|
|
1584 | { |
|
|
1585 | adns_state ads = (adns_state)w->data; |
|
|
1586 | update_now (EV_A); |
|
|
1587 | |
|
|
1588 | if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1589 | if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1590 | } |
|
|
1591 | |
|
|
1592 | // do not ever call adns_afterpoll |
|
|
1593 | |
|
|
1594 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1595 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1596 | their poll function. The drawback with this solution is that the main |
|
|
1597 | loop is now no longer controllable by EV. The C<Glib::EV> module does |
|
|
1598 | this. |
|
|
1599 | |
|
|
1600 | static gint |
|
|
1601 | event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1602 | { |
|
|
1603 | int got_events = 0; |
|
|
1604 | |
|
|
1605 | for (n = 0; n < nfds; ++n) |
|
|
1606 | // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1607 | |
|
|
1608 | if (timeout >= 0) |
|
|
1609 | // create/start timer |
|
|
1610 | |
|
|
1611 | // poll |
|
|
1612 | ev_loop (EV_A_ 0); |
|
|
1613 | |
|
|
1614 | // stop timer again |
|
|
1615 | if (timeout >= 0) |
|
|
1616 | ev_timer_stop (EV_A_ &to); |
|
|
1617 | |
|
|
1618 | // stop io watchers again - their callbacks should have set |
|
|
1619 | for (n = 0; n < nfds; ++n) |
|
|
1620 | ev_io_stop (EV_A_ iow [n]); |
|
|
1621 | |
|
|
1622 | return got_events; |
1536 | } |
1623 | } |
1537 | |
1624 | |
1538 | |
1625 | |
1539 | =head2 C<ev_embed> - when one backend isn't enough... |
1626 | =head2 C<ev_embed> - when one backend isn't enough... |
1540 | |
1627 | |
… | |
… | |
1744 | |
1831 | |
1745 | To use it, |
1832 | To use it, |
1746 | |
1833 | |
1747 | #include <ev++.h> |
1834 | #include <ev++.h> |
1748 | |
1835 | |
1749 | (it is not installed by default). This automatically includes F<ev.h> |
1836 | This automatically includes F<ev.h> and puts all of its definitions (many |
1750 | and puts all of its definitions (many of them macros) into the global |
1837 | of them macros) into the global namespace. All C++ specific things are |
1751 | namespace. All C++ specific things are put into the C<ev> namespace. |
1838 | put into the C<ev> namespace. It should support all the same embedding |
|
|
1839 | options as F<ev.h>, most notably C<EV_MULTIPLICITY>. |
1752 | |
1840 | |
1753 | It should support all the same embedding options as F<ev.h>, most notably |
1841 | Care has been taken to keep the overhead low. The only data member the C++ |
1754 | C<EV_MULTIPLICITY>. |
1842 | classes add (compared to plain C-style watchers) is the event loop pointer |
|
|
1843 | that the watcher is associated with (or no additional members at all if |
|
|
1844 | you disable C<EV_MULTIPLICITY> when embedding libev). |
|
|
1845 | |
|
|
1846 | Currently, functions, and static and non-static member functions can be |
|
|
1847 | used as callbacks. Other types should be easy to add as long as they only |
|
|
1848 | need one additional pointer for context. If you need support for other |
|
|
1849 | types of functors please contact the author (preferably after implementing |
|
|
1850 | it). |
1755 | |
1851 | |
1756 | Here is a list of things available in the C<ev> namespace: |
1852 | Here is a list of things available in the C<ev> namespace: |
1757 | |
1853 | |
1758 | =over 4 |
1854 | =over 4 |
1759 | |
1855 | |
… | |
… | |
1775 | |
1871 | |
1776 | All of those classes have these methods: |
1872 | All of those classes have these methods: |
1777 | |
1873 | |
1778 | =over 4 |
1874 | =over 4 |
1779 | |
1875 | |
1780 | =item ev::TYPE::TYPE (object *, object::method *) |
1876 | =item ev::TYPE::TYPE () |
1781 | |
1877 | |
1782 | =item ev::TYPE::TYPE (object *, object::method *, struct ev_loop *) |
1878 | =item ev::TYPE::TYPE (struct ev_loop *) |
1783 | |
1879 | |
1784 | =item ev::TYPE::~TYPE |
1880 | =item ev::TYPE::~TYPE |
1785 | |
1881 | |
1786 | The constructor takes a pointer to an object and a method pointer to |
1882 | The constructor (optionally) takes an event loop to associate the watcher |
1787 | the event handler callback to call in this class. The constructor calls |
1883 | with. If it is omitted, it will use C<EV_DEFAULT>. |
1788 | C<ev_init> for you, which means you have to call the C<set> method |
1884 | |
1789 | before starting it. If you do not specify a loop then the constructor |
1885 | The constructor calls C<ev_init> for you, which means you have to call the |
1790 | automatically associates the default loop with this watcher. |
1886 | C<set> method before starting it. |
|
|
1887 | |
|
|
1888 | It will not set a callback, however: You have to call the templated C<set> |
|
|
1889 | method to set a callback before you can start the watcher. |
|
|
1890 | |
|
|
1891 | (The reason why you have to use a method is a limitation in C++ which does |
|
|
1892 | not allow explicit template arguments for constructors). |
1791 | |
1893 | |
1792 | The destructor automatically stops the watcher if it is active. |
1894 | The destructor automatically stops the watcher if it is active. |
|
|
1895 | |
|
|
1896 | =item w->set<class, &class::method> (object *) |
|
|
1897 | |
|
|
1898 | This method sets the callback method to call. The method has to have a |
|
|
1899 | signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as |
|
|
1900 | first argument and the C<revents> as second. The object must be given as |
|
|
1901 | parameter and is stored in the C<data> member of the watcher. |
|
|
1902 | |
|
|
1903 | This method synthesizes efficient thunking code to call your method from |
|
|
1904 | the C callback that libev requires. If your compiler can inline your |
|
|
1905 | callback (i.e. it is visible to it at the place of the C<set> call and |
|
|
1906 | your compiler is good :), then the method will be fully inlined into the |
|
|
1907 | thunking function, making it as fast as a direct C callback. |
|
|
1908 | |
|
|
1909 | Example: simple class declaration and watcher initialisation |
|
|
1910 | |
|
|
1911 | struct myclass |
|
|
1912 | { |
|
|
1913 | void io_cb (ev::io &w, int revents) { } |
|
|
1914 | } |
|
|
1915 | |
|
|
1916 | myclass obj; |
|
|
1917 | ev::io iow; |
|
|
1918 | iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
1919 | |
|
|
1920 | =item w->set<function> (void *data = 0) |
|
|
1921 | |
|
|
1922 | Also sets a callback, but uses a static method or plain function as |
|
|
1923 | callback. The optional C<data> argument will be stored in the watcher's |
|
|
1924 | C<data> member and is free for you to use. |
|
|
1925 | |
|
|
1926 | The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>. |
|
|
1927 | |
|
|
1928 | See the method-C<set> above for more details. |
|
|
1929 | |
|
|
1930 | Example: |
|
|
1931 | |
|
|
1932 | static void io_cb (ev::io &w, int revents) { } |
|
|
1933 | iow.set <io_cb> (); |
1793 | |
1934 | |
1794 | =item w->set (struct ev_loop *) |
1935 | =item w->set (struct ev_loop *) |
1795 | |
1936 | |
1796 | Associates a different C<struct ev_loop> with this watcher. You can only |
1937 | Associates a different C<struct ev_loop> with this watcher. You can only |
1797 | do this when the watcher is inactive (and not pending either). |
1938 | do this when the watcher is inactive (and not pending either). |
1798 | |
1939 | |
1799 | =item w->set ([args]) |
1940 | =item w->set ([args]) |
1800 | |
1941 | |
1801 | Basically the same as C<ev_TYPE_set>, with the same args. Must be |
1942 | Basically the same as C<ev_TYPE_set>, with the same args. Must be |
1802 | called at least once. Unlike the C counterpart, an active watcher gets |
1943 | called at least once. Unlike the C counterpart, an active watcher gets |
1803 | automatically stopped and restarted. |
1944 | automatically stopped and restarted when reconfiguring it with this |
|
|
1945 | method. |
1804 | |
1946 | |
1805 | =item w->start () |
1947 | =item w->start () |
1806 | |
1948 | |
1807 | Starts the watcher. Note that there is no C<loop> argument as the |
1949 | Starts the watcher. Note that there is no C<loop> argument, as the |
1808 | constructor already takes the loop. |
1950 | constructor already stores the event loop. |
1809 | |
1951 | |
1810 | =item w->stop () |
1952 | =item w->stop () |
1811 | |
1953 | |
1812 | Stops the watcher if it is active. Again, no C<loop> argument. |
1954 | Stops the watcher if it is active. Again, no C<loop> argument. |
1813 | |
1955 | |
… | |
… | |
1838 | |
1980 | |
1839 | myclass (); |
1981 | myclass (); |
1840 | } |
1982 | } |
1841 | |
1983 | |
1842 | myclass::myclass (int fd) |
1984 | myclass::myclass (int fd) |
1843 | : io (this, &myclass::io_cb), |
|
|
1844 | idle (this, &myclass::idle_cb) |
|
|
1845 | { |
1985 | { |
|
|
1986 | io .set <myclass, &myclass::io_cb > (this); |
|
|
1987 | idle.set <myclass, &myclass::idle_cb> (this); |
|
|
1988 | |
1846 | io.start (fd, ev::READ); |
1989 | io.start (fd, ev::READ); |
1847 | } |
1990 | } |
1848 | |
1991 | |
1849 | |
1992 | |
1850 | =head1 MACRO MAGIC |
1993 | =head1 MACRO MAGIC |
… | |
… | |
2255 | |
2398 | |
2256 | In this section the complexities of (many of) the algorithms used inside |
2399 | In this section the complexities of (many of) the algorithms used inside |
2257 | libev will be explained. For complexity discussions about backends see the |
2400 | libev will be explained. For complexity discussions about backends see the |
2258 | documentation for C<ev_default_init>. |
2401 | documentation for C<ev_default_init>. |
2259 | |
2402 | |
|
|
2403 | All of the following are about amortised time: If an array needs to be |
|
|
2404 | extended, libev needs to realloc and move the whole array, but this |
|
|
2405 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2406 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2407 | it is much faster and asymptotically approaches constant time. |
|
|
2408 | |
2260 | =over 4 |
2409 | =over 4 |
2261 | |
2410 | |
2262 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2411 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2263 | |
2412 | |
2264 | This means that, when you have a watcher that triggers in one hour and |
2413 | This means that, when you have a watcher that triggers in one hour and |
… | |
… | |
2270 | That means that for changing a timer costs less than removing/adding them |
2419 | That means that for changing a timer costs less than removing/adding them |
2271 | as only the relative motion in the event queue has to be paid for. |
2420 | as only the relative motion in the event queue has to be paid for. |
2272 | |
2421 | |
2273 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2422 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2274 | |
2423 | |
2275 | These just add the watcher into an array or at the head of a list. If |
2424 | These just add the watcher into an array or at the head of a list. |
2276 | the array needs to be extended libev needs to realloc and move the whole |
|
|
2277 | array, but this happen asymptotically less and less with more watchers, |
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2278 | thus amortised O(1). |
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2279 | |
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2280 | =item Stopping check/prepare/idle watchers: O(1) |
2425 | =item Stopping check/prepare/idle watchers: O(1) |
2281 | |
2426 | |
2282 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2427 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2283 | |
2428 | |
2284 | These watchers are stored in lists then need to be walked to find the |
2429 | These watchers are stored in lists then need to be walked to find the |