--- AnyEvent/lib/AnyEvent.pm 2009/08/09 23:45:40 1.280 +++ AnyEvent/lib/AnyEvent.pm 2012/12/06 12:10:09 1.409 @@ -2,19 +2,22 @@ AnyEvent - the DBI of event loop programming -EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt -and POE are various supported event loops/environments. +EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt, +FLTK and POE are various supported event loops/environments. =head1 SYNOPSIS use AnyEvent; - # file descriptor readable + # if you prefer function calls, look at the AE manpage for + # an alternative API. + + # file handle or descriptor readable my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... }); # one-shot or repeating timers my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); - my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... + my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...); print AnyEvent->now; # prints current event loop time print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. @@ -45,7 +48,9 @@ =head1 SUPPORT -There is a mailinglist for discussing all things AnyEvent, and an IRC +An FAQ document is available as L. + +There also is a mailinglist for discussing all things AnyEvent, and an IRC channel, too. See the AnyEvent project page at the B...), using them in your module is -like joining a cult: After you joined, you are dependent on them and you +like joining a cult: After you join, you are dependent on them and you cannot use anything else, as they are simply incompatible to everything that isn't them. What's worse, all the potential users of your module are I forced to use the same event loop you use. AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works fine. AnyEvent + Tk works fine etc. etc. but none of these work together -with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if -your module uses one of those, every user of your module has to use it, -too. But if your module uses AnyEvent, it works transparently with all -event models it supports (including stuff like IO::Async, as long as those -use one of the supported event loops. It is trivial to add new event loops -to AnyEvent, too, so it is future-proof). +with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module +uses one of those, every user of your module has to use it, too. But if +your module uses AnyEvent, it works transparently with all event models it +supports (including stuff like IO::Async, as long as those use one of the +supported event loops. It is easy to add new event loops to AnyEvent, too, +so it is future-proof). In addition to being free of having to use I, AnyEvent also is free of bloat and policy: with POE or similar modules, you get an enormous amount of code and strict rules you have to -follow. AnyEvent, on the other hand, is lean and up to the point, by only +follow. AnyEvent, on the other hand, is lean and to the point, by only offering the functionality that is necessary, in as thin as a wrapper as technically possible. @@ -108,24 +113,22 @@ =head1 DESCRIPTION -L provides an identical interface to multiple event loops. This -allows module authors to utilise an event loop without forcing module -users to use the same event loop (as only a single event loop can coexist -peacefully at any one time). +L provides a uniform interface to various event loops. This +allows module authors to use event loop functionality without forcing +module users to use a specific event loop implementation (since more +than one event loop cannot coexist peacefully). The interface itself is vaguely similar, but not identical to the L module. During the first call of any watcher-creation method, the module tries to detect the currently loaded event loop by probing whether one of the -following modules is already loaded: L, -L, L, L, L, L, L, -L. The first one found is used. If none are found, the module tries -to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl -adaptor should always succeed) in the order given. The first one that can -be successfully loaded will be used. If, after this, still none could be -found, AnyEvent will fall back to a pure-perl event loop, which is not -very efficient, but should work everywhere. +following modules is already loaded: L, L, +L, L, L, L, L, L. The first one +found is used. If none are detected, the module tries to load the first +four modules in the order given; but note that if L is not +available, the pure-perl L should always work, so +the other two are not normally tried. Because AnyEvent first checks for modules that are already loaded, loading an event model explicitly before first using AnyEvent will likely make @@ -137,12 +140,13 @@ # .. AnyEvent will likely default to Tk The I means that, if any module loads another event model and -starts using it, all bets are off. Maybe you should tell their authors to -use AnyEvent so their modules work together with others seamlessly... - -The pure-perl implementation of AnyEvent is called -C. Like other event modules you can load it -explicitly and enjoy the high availability of that event loop :) +starts using it, all bets are off - this case should be very rare though, +as very few modules hardcode event loops without announcing this very +loudly. + +The pure-perl implementation of AnyEvent is called C. Like +other event modules you can load it explicitly and enjoy the high +availability of that event loop :) =head1 WATCHERS @@ -157,11 +161,11 @@ Note that B potentially in use by the event loop (such as C<$_> or C<$[>) and that B<< -callbacks must not C >>. The former is good programming practise in +callbacks must not C >>. The former is good programming practice in Perl and the latter stems from the fact that exception handling differs widely between event loops. -To disable the watcher you have to destroy it (e.g. by setting the +To disable a watcher you have to destroy it (e.g. by setting the variable you store it in to C or otherwise deleting all references to it). @@ -170,7 +174,7 @@ Many watchers either are used with "recursion" (repeating timers for example), or need to refer to their watcher object in other ways. -An any way to achieve that is this pattern: +One way to achieve that is this pattern: my $w; $w = AnyEvent->type (arg => value ..., cb => sub { # you can use $w here, for example to undef it @@ -212,7 +216,7 @@ You must not close a file handle as long as any watcher is active on the underlying file descriptor. -Some event loops issue spurious readyness notifications, so you should +Some event loops issue spurious readiness notifications, so you should always use non-blocking calls when reading/writing from/to your file handles. @@ -246,14 +250,14 @@ presence is undefined and you cannot rely on them. Portable AnyEvent callbacks cannot use arguments passed to time watcher callbacks. -The callback will normally be invoked once only. If you specify another +The callback will normally be invoked only once. If you specify another parameter, C, as a strictly positive number (> 0), then the callback will be invoked regularly at that interval (in fractional seconds) after the first invocation. If C is specified with a -false value, then it is treated as if it were missing. +false value, then it is treated as if it were not specified at all. The callback will be rescheduled before invoking the callback, but no -attempt is done to avoid timer drift in most backends, so the interval is +attempt is made to avoid timer drift in most backends, so the interval is only approximate. Example: fire an event after 7.7 seconds. @@ -281,10 +285,10 @@ use absolute time internally. This makes a difference when your clock "jumps", for example, when ntp decides to set your clock backwards from the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to -fire "after" a second might actually take six years to finally fire. +fire "after a second" might actually take six years to finally fire. AnyEvent cannot compensate for this. The only event loop that is conscious -about these issues is L, which offers both relative (ev_timer, based +of these issues is L, which offers both relative (ev_timer, based on true relative time) and absolute (ev_periodic, based on wallclock time) timers. @@ -316,15 +320,15 @@ This function is also often faster then C<< AnyEvent->time >>, and thus the preferred method if you want some timestamp (for example, -L uses this to update it's activity timeouts). +L uses this to update its activity timeouts). The rest of this section is only of relevance if you try to be very exact -with your timing, you can skip it without bad conscience. +with your timing; you can skip it without a bad conscience. For a practical example of when these times differ, consider L and L and the following set-up: -The event loop is running and has just invoked one of your callback at +The event loop is running and has just invoked one of your callbacks at time=500 (assume no other callbacks delay processing). In your callback, you wait a second by executing C (blocking the process for a second) and then (at time=501) you create a relative timer that fires @@ -354,9 +358,9 @@ =item AnyEvent->now_update -Some event loops (such as L or L) cache -the current time for each loop iteration (see the discussion of L<< -AnyEvent->now >>, above). +Some event loops (such as L or L) cache the current +time for each loop iteration (see the discussion of L<< AnyEvent->now >>, +above). When a callback runs for a long time (or when the process sleeps), then this "current" time will differ substantially from the real time, which @@ -365,6 +369,13 @@ When this is the case, you can call this method, which will update the event loop's idea of "current time". +A typical example would be a script in a web server (e.g. C) - +when mod_perl executes the script, then the event loop will have the wrong +idea about the "current time" (being potentially far in the past, when the +script ran the last time). In that case you should arrange a call to C<< +AnyEvent->now_update >> each time the web server process wakes up again +(e.g. at the start of your script, or in a handler). + Note that updating the time I cause some events to be handled. =back @@ -398,33 +409,48 @@ my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); +=head3 Restart Behaviour + +While restart behaviour is up to the event loop implementation, most will +not restart syscalls (that includes L and AnyEvent's +pure perl implementation). + +=head3 Safe/Unsafe Signals + +Perl signals can be either "safe" (synchronous to opcode handling) +or "unsafe" (asynchronous) - the former might delay signal delivery +indefinitely, the latter might corrupt your memory. + +AnyEvent signal handlers are, in addition, synchronous to the event loop, +i.e. they will not interrupt your running perl program but will only be +called as part of the normal event handling (just like timer, I/O etc. +callbacks, too). + =head3 Signal Races, Delays and Workarounds -Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching -callbacks to signals in a generic way, which is a pity, as you cannot -do race-free signal handling in perl, requiring C libraries for -this. AnyEvent will try to do it's best, which means in some cases, -signals will be delayed. The maximum time a signal might be delayed is -specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This -variable can be changed only before the first signal watcher is created, -and should be left alone otherwise. This variable determines how often -AnyEvent polls for signals (in case a wake-up was missed). Higher values -will cause fewer spurious wake-ups, which is better for power and CPU -saving. +Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support +attaching callbacks to signals in a generic way, which is a pity, +as you cannot do race-free signal handling in perl, requiring +C libraries for this. AnyEvent will try to do its best, which +means in some cases, signals will be delayed. The maximum time +a signal might be delayed is 10 seconds by default, but can +be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or +C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the L +section for details. All these problems can be avoided by installing the optional L module, which works with most event loops. It will not work with inherently broken event loops such as L or L -(and not with L currently, as POE does it's own workaround with -one-second latency). For those, you just have to suffer the delays. +(and not with L currently). For those, you just have to suffer the +delays. =head2 CHILD PROCESS WATCHERS $w = AnyEvent->child (pid => , cb => ); -You can also watch on a child process exit and catch its exit status. +You can also watch for a child process exit and catch its exit status. -The child process is specified by the C argument (one some backends, +The child process is specified by the C argument (on some backends, using C<0> watches for any child process exit, on others this will croak). The watcher will be triggered only when the child process has finished and an exit status is available, not on any trace events @@ -456,8 +482,8 @@ C). As most event loops do not support waiting for child events, they will be -emulated by AnyEvent in most cases, in which the latency and race problems -mentioned in the description of signal watchers apply. +emulated by AnyEvent in most cases, in which case the latency and race +problems mentioned in the description of signal watchers apply. Example: fork a process and wait for it @@ -481,16 +507,19 @@ $w = AnyEvent->idle (cb => ); -Sometimes there is a need to do something, but it is not so important -to do it instantly, but only when there is nothing better to do. This -"nothing better to do" is usually defined to be "no other events need -attention by the event loop". - -Idle watchers ideally get invoked when the event loop has nothing -better to do, just before it would block the process to wait for new -events. Instead of blocking, the idle watcher is invoked. +This will repeatedly invoke the callback after the process becomes idle, +until either the watcher is destroyed or new events have been detected. -Most event loops unfortunately do not really support idle watchers (only +Idle watchers are useful when there is a need to do something, but it +is not so important (or wise) to do it instantly. The callback will be +invoked only when there is "nothing better to do", which is usually +defined as "all outstanding events have been handled and no new events +have been detected". That means that idle watchers ideally get invoked +when the event loop has just polled for new events but none have been +detected. Instead of blocking to wait for more events, the idle watchers +will be invoked. + +Unfortunately, most event loops do not really support idle watchers (only EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent will simply call the callback "from time to time". @@ -528,8 +557,8 @@ AnyEvent is slightly different: it expects somebody else to run the event loop and will only block when necessary (usually when told by the user). -The instrument to do that is called a "condition variable", so called -because they represent a condition that must become true. +The tool to do that is called a "condition variable", so called because +they represent a condition that must become true. Now is probably a good time to look at the examples further below. @@ -544,13 +573,29 @@ were a callback, read about the caveats in the description for the C<< ->send >> method). -Condition variables are similar to callbacks, except that you can -optionally wait for them. They can also be called merge points - points -in time where multiple outstanding events have been processed. And yet -another way to call them is transactions - each condition variable can be -used to represent a transaction, which finishes at some point and delivers -a result. And yet some people know them as "futures" - a promise to -compute/deliver something that you can wait for. +Since condition variables are the most complex part of the AnyEvent API, here are +some different mental models of what they are - pick the ones you can connect to: + +=over 4 + +=item * Condition variables are like callbacks - you can call them (and pass them instead +of callbacks). Unlike callbacks however, you can also wait for them to be called. + +=item * Condition variables are signals - one side can emit or send them, +the other side can wait for them, or install a handler that is called when +the signal fires. + +=item * Condition variables are like "Merge Points" - points in your program +where you merge multiple independent results/control flows into one. + +=item * Condition variables represent a transaction - functions that start +some kind of transaction can return them, leaving the caller the choice +between waiting in a blocking fashion, or setting a callback. + +=item * Condition variables represent future values, or promises to deliver +some result, long before the result is available. + +=back Condition variables are very useful to signal that something has finished, for example, if you write a module that does asynchronous http requests, @@ -573,7 +618,7 @@ used by AnyEvent itself are all named C<_ae_XXX> to make subclassing easy (it is often useful to build your own transaction class on top of AnyEvent). To subclass, use C as base class and call -it's C method in your own C method. +its C method in your own C method. There are two "sides" to a condition variable - the "producer side" which eventually calls C<< -> send >>, and the "consumer side", which waits @@ -581,21 +626,21 @@ Example: wait for a timer. - # wait till the result is ready - my $result_ready = AnyEvent->condvar; + # condition: "wait till the timer is fired" + my $timer_fired = AnyEvent->condvar; - # do something such as adding a timer - # or socket watcher the calls $result_ready->send - # when the "result" is ready. + # create the timer - we could wait for, say + # a handle becomign ready, or even an + # AnyEvent::HTTP request to finish, but # in this case, we simply use a timer: my $w = AnyEvent->timer ( after => 1, - cb => sub { $result_ready->send }, + cb => sub { $timer_fired->send }, ); # this "blocks" (while handling events) till the callback - # calls -recv; + # calls ->send + $timer_fired->recv; Example: wait for a timer, but take advantage of the fact that condition variables are also callable directly. @@ -648,14 +693,14 @@ =item $cv->croak ($error) -Similar to send, but causes all call's to C<< ->recv >> to invoke +Similar to send, but causes all calls to C<< ->recv >> to invoke C with the given error message/object/scalar. This can be used to signal any errors to the condition variable user/consumer. Doing it this way instead of calling C directly -delays the error detetcion, but has the overwhelmign advantage that it +delays the error detection, but has the overwhelming advantage that it diagnoses the error at the place where the result is expected, and not -deep in some event clalback without connection to the actual code causing +deep in some event callback with no connection to the actual code causing the problem. =item $cv->begin ([group callback]) @@ -703,7 +748,7 @@ The ping example mentioned above is slightly more complicated, as the there are results to be passwd back, and the number of tasks that are -begung can potentially be zero: +begun can potentially be zero: my $cv = AnyEvent->condvar; @@ -720,6 +765,10 @@ $cv->end; + ... + + my $results = $cv->recv; + This code fragment supposedly pings a number of hosts and calls C after results for all then have have been gathered - in any order. To achieve this, the code issues a call to C when it starts @@ -734,7 +783,7 @@ doesn't execute once). This is the general pattern when you "fan out" into multiple (but -potentially none) subrequests: use an outer C/C pair to set +potentially zero) subrequests: use an outer C/C pair to set the callback and ensure C is called at least once, and then, for each subrequest you start, call C and for each subrequest you finish, call C. @@ -751,7 +800,7 @@ =item $cv->recv Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak ->> methods have been called on c<$cv>, while servicing other watchers +>> methods have been called on C<$cv>, while servicing other watchers normally. You can only wait once on a condition - additional calls are valid but @@ -764,11 +813,15 @@ in scalar context only the first one will be returned. Note that doing a blocking wait in a callback is not supported by any -event loop, that is, recursive invocation of a blocking C<< ->recv ->> is not allowed, and the C call will C if such a -condition is detected. This condition can be slightly loosened by using -L, which allows you to do a blocking C<< ->recv >> from -any thread that doesn't run the event loop itself. +event loop, that is, recursive invocation of a blocking C<< ->recv >> is +not allowed and the C call will C if such a condition is +detected. This requirement can be dropped by relying on L +, which allows you to do a blocking C<< ->recv >> from any thread +that doesn't run the event loop itself. L is loaded +automatically when L is used with L, so code does not need +to do anything special to take advantage of that: any code that would +normally block your program because it calls C, be executed in an +C thread instead without blocking other threads. Not all event models support a blocking wait - some die in that case (programs might want to do that to stay interactive), so I> never blocks by setting a callback and +You can ensure that C<< ->recv >> never blocks by setting a callback and only calling C<< ->recv >> from within that callback (or at a later time). This will work even when the event loop does not support blocking waits otherwise. @@ -793,10 +846,11 @@ This is a mutator function that returns the callback set and optionally replaces it before doing so. -The callback will be called when the condition becomes (or already was) -"true", i.e. when C or C are called (or were called), with -the only argument being the condition variable itself. Calling C -inside the callback or at any later time is guaranteed not to block. +The callback will be called when the condition becomes "true", i.e. when +C or C are called, with the only argument being the +condition variable itself. If the condition is already true, the +callback is called immediately when it is set. Calling C inside +the callback or at any later time is guaranteed not to block. =back @@ -814,11 +868,11 @@ AnyEvent itself. AnyEvent::Impl::EV based on EV (interface to libev, best choice). - AnyEvent::Impl::Perl pure-perl implementation, fast and portable. + AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable. =item Backends that are transparently being picked up when they are used. -These will be used when they are currently loaded when the first watcher +These will be used if they are already loaded when the first watcher is created, in which case it is assumed that the application is using them. This means that AnyEvent will automatically pick the right backend when the main program loads an event module before anything starts to @@ -830,6 +884,9 @@ AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. AnyEvent::Impl::POE based on POE, very slow, some limitations. AnyEvent::Impl::Irssi used when running within irssi. + AnyEvent::Impl::IOAsync based on IO::Async. + AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. + AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding). =item Backends with special needs. @@ -840,14 +897,6 @@ AnyEvent::Impl::Qt based on Qt. -Support for IO::Async can only be partial, as it is too broken and -architecturally limited to even support the AnyEvent API. It also -is the only event loop that needs the loop to be set explicitly, so -it can only be used by a main program knowing about AnyEvent. See -L for the gory details. - - AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed. - =item Event loops that are indirectly supported via other backends. Some event loops can be supported via other modules: @@ -882,7 +931,7 @@ Afterwards it contains the event model that is being used, which is the name of the Perl class implementing the model. This class is usually one -of the C modules, but can be any other class in the +of the C modules, but can be any other class in the case AnyEvent has been extended at runtime (e.g. in I it will be C). @@ -891,7 +940,11 @@ Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model if necessary. You should only call this function right before you would have created an AnyEvent watcher anyway, that is, as late as possible at -runtime, and not e.g. while initialising of your module. +runtime, and not e.g. during initialisation of your module. + +The effect of calling this function is as if a watcher had been created +(specifically, actions that happen "when the first watcher is created" +happen when calling detetc as well). If you need to do some initialisation before AnyEvent watchers are created, use C. @@ -899,7 +952,7 @@ =item $guard = AnyEvent::post_detect { BLOCK } Arranges for the code block to be executed as soon as the event model is -autodetected (or immediately if this has already happened). +autodetected (or immediately if that has already happened). The block will be executed I the actual backend has been detected (C<$AnyEvent::MODEL> is set), but I any watchers have been @@ -918,7 +971,7 @@ a case where this is useful. Example: Create a watcher for the IO::AIO module and store it in -C<$WATCHER>. Only do so after the event loop is initialised, though. +C<$WATCHER>, but do so only do so after the event loop is initialised. our WATCHER; @@ -936,21 +989,92 @@ =item @AnyEvent::post_detect If there are any code references in this array (you can C to it -before or after loading AnyEvent), then they will called directly after -the event loop has been chosen. +before or after loading AnyEvent), then they will be called directly +after the event loop has been chosen. You should check C<$AnyEvent::MODEL> before adding to this array, though: if it is defined then the event loop has already been detected, and the array will be ignored. Best use C when your application allows -it,as it takes care of these details. +it, as it takes care of these details. This variable is mainly useful for modules that can do something useful when AnyEvent is used and thus want to know when it is initialised, but do not need to even load it by default. This array provides the means to hook into AnyEvent passively, without loading it. +Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used +together, you could put this into Coro (this is the actual code used by +Coro to accomplish this): + + if (defined $AnyEvent::MODEL) { + # AnyEvent already initialised, so load Coro::AnyEvent + require Coro::AnyEvent; + } else { + # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent + # as soon as it is + push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; + } + +=item AnyEvent::postpone { BLOCK } + +Arranges for the block to be executed as soon as possible, but not before +the call itself returns. In practise, the block will be executed just +before the event loop polls for new events, or shortly afterwards. + +This function never returns anything (to make the C idiom more useful. + +To understand the usefulness of this function, consider a function that +asynchronously does something for you and returns some transaction +object or guard to let you cancel the operation. For example, +C: + + # start a conenction attempt unless one is active + $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub { + delete $self->{connect_guard}; + ... + }; + +Imagine that this function could instantly call the callback, for +example, because it detects an obvious error such as a negative port +number. Invoking the callback before the function returns causes problems +however: the callback will be called and will try to delete the guard +object. But since the function hasn't returned yet, there is nothing to +delete. When the function eventually returns it will assign the guard +object to C<< $self->{connect_guard} >>, where it will likely never be +deleted, so the program thinks it is still trying to connect. + +This is where C should be used. Instead of calling the +callback directly on error: + + $cb->(undef), return # signal error to callback, BAD! + if $some_error_condition; + +It should use C: + + AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later + if $some_error_condition; + +=item AnyEvent::log $level, $msg[, @args] + +Log the given C<$msg> at the given C<$level>. + +If L is not loaded then this function makes a simple test +to see whether the message will be logged. If the test succeeds it will +load AnyEvent::Log and call C - consequently, look at +the L documentation for details. + +If the test fails it will simply return. Right now this happens when a +numerical loglevel is used and it is larger than the level specified via +C<$ENV{PERL_ANYEVENT_VERBOSE}>. + +If you want to sprinkle loads of logging calls around your code, consider +creating a logger callback with the C function, +which can reduce typing, codesize and can reduce the logging overhead +enourmously. + =back =head1 WHAT TO DO IN A MODULE @@ -970,17 +1094,19 @@ It is fine, however, to call C<< ->recv >> when the user of your module requests it (i.e. if you create a http request object ad have a method -called C that returns the results, it should call C<< ->recv >> -freely, as the user of your module knows what she is doing. always). +called C that returns the results, it may call C<< ->recv >> +freely, as the user of your module knows what she is doing. Always). =head1 WHAT TO DO IN THE MAIN PROGRAM There will always be a single main program - the only place that should dictate which event model to use. -If it doesn't care, it can just "use AnyEvent" and use it itself, or not -do anything special (it does not need to be event-based) and let AnyEvent -decide which implementation to chose if some module relies on it. +If the program is not event-based, it need not do anything special, even +when it depends on a module that uses an AnyEvent. If the program itself +uses AnyEvent, but does not care which event loop is used, all it needs +to do is C. In either case, AnyEvent will choose the best +available loop implementation. If the main program relies on a specific event model - for example, in Gtk2 programs you have to rely on the Glib module - you should load the @@ -988,10 +1114,10 @@ speaking, you should load it as early as possible. The reason is that modules might create watchers when they are loaded, and AnyEvent will decide on the event model to use as soon as it creates watchers, and it -might chose the wrong one unless you load the correct one yourself. +might choose the wrong one unless you load the correct one yourself. You can chose to use a pure-perl implementation by loading the -C module, which gives you similar behaviour +C module, which gives you similar behaviour everywhere, but letting AnyEvent chose the model is generally better. =head2 MAINLOOP EMULATION @@ -1014,16 +1140,19 @@ =head1 OTHER MODULES The following is a non-exhaustive list of additional modules that use -AnyEvent as a client and can therefore be mixed easily with other AnyEvent -modules and other event loops in the same program. Some of the modules -come with AnyEvent, most are available via CPAN. +AnyEvent as a client and can therefore be mixed easily with other +AnyEvent modules and other event loops in the same program. Some of the +modules come as part of AnyEvent, the others are available via CPAN (see +L for +a longer non-exhaustive list), and the list is heavily biased towards +modules of the AnyEvent author himself :) =over 4 =item L -Contains various utility functions that replace often-used but blocking -functions such as C by event-/callback-based versions. +Contains various utility functions that replace often-used blocking +functions such as C with event/callback-based versions. =item L @@ -1035,70 +1164,66 @@ Provide read and write buffers, manages watchers for reads and writes, supports raw and formatted I/O, I/O queued and fully transparent and -non-blocking SSL/TLS (via L. +non-blocking SSL/TLS (via L). =item L Provides rich asynchronous DNS resolver capabilities. -=item L - -A simple-to-use HTTP library that is capable of making a lot of concurrent -HTTP requests. - -=item L - -Provides a simple web application server framework. +=item L, L, L, L, L, L -=item L - -The fastest ping in the west. - -=item L - -Executes L requests asynchronously in a proxy process. +Implement event-based interfaces to the protocols of the same name (for +the curious, IGS is the International Go Server and FCP is the Freenet +Client Protocol). =item L -Truly asynchronous I/O, should be in the toolbox of every event -programmer. AnyEvent::AIO transparently fuses L and AnyEvent -together. - -=item L +Truly asynchronous (as opposed to non-blocking) I/O, should be in the +toolbox of every event programmer. AnyEvent::AIO transparently fuses +L and AnyEvent together, giving AnyEvent access to event-based +file I/O, and much more. + +=item L + +AnyEvent is good for non-blocking stuff, but it can't detect file or +path changes (e.g. "watch this directory for new files", "watch this +file for changes"). The L module promises to +do just that in a portbale fashion, supporting inotify on GNU/Linux and +some weird, without doubt broken, stuff on OS X to monitor files. It can +fall back to blocking scans at regular intervals transparently on other +platforms, so it's about as portable as it gets. -Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses -L and AnyEvent together. +(I haven't used it myself, but I haven't heard anybody complaining about +it yet). -=item L - -A non-blocking interface to gpsd, a daemon delivering GPS information. - -=item L - -AnyEvent based IRC client module family (replacing the older Net::IRC3). +=item L -=item L +Executes L requests asynchronously in a proxy process for you, +notifying you in an event-based way when the operation is finished. -AnyEvent based XMPP (Jabber protocol) module family (replacing the older -Net::XMPP2>. +=item L -=item L +A simple embedded webserver. -A non-blocking interface to the Internet Go Server protocol (used by -L). +=item L -=item L +The fastest ping in the west. -AnyEvent-based implementation of the Freenet Client Protocol, birthplace -of AnyEvent. +=item L -=item L +Has special support for AnyEvent via L, which allows you +to simply invert the flow control - don't call us, we will call you: -High level API for event-based execution flow control. + async { + Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it + print "5 seconds later!\n"; -=item L + Coro::AnyEvent::readable *STDIN; # uses an I/O watcher + my $line = ; # works for ttys -Has special support for AnyEvent via L. + AnyEvent::HTTP::http_get "url", Coro::rouse_cb; + my ($body, $hdr) = Coro::rouse_wait; + }; =back @@ -1108,9 +1233,10 @@ # basically a tuned-down version of common::sense sub common_sense { - # no warnings - ${^WARNING_BITS} ^= ${^WARNING_BITS}; - # use strict vars subs + # from common:.sense 3.5 + local $^W; + ${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00"; + # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl) $^H |= 0x00000600; } @@ -1118,160 +1244,291 @@ use Carp (); -our $VERSION = '5.0'; +our $VERSION = '7.04'; our $MODEL; - -our $AUTOLOAD; our @ISA; - our @REGISTRY; - -our $WIN32; - our $VERBOSE; +our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred +our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!) BEGIN { - eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; - eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; + require "AnyEvent/constants.pl"; + + eval "sub TAINT (){" . (${^TAINT}*1) . "}"; delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} if ${^TAINT}; - $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; + $ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"} + for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV; -} + @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = () + if ${^TAINT}; -our $MAX_SIGNAL_LATENCY = 10; + # $ENV{PERL_ANYEVENT_xxx} now valid -our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred + $VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4; -{ my $idx; $PROTOCOL{$_} = ++$idx for reverse split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; } -my @models = ( - [EV:: => AnyEvent::Impl::EV:: , 1], - [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1], +our @post_detect; + +sub post_detect(&) { + my ($cb) = @_; + + push @post_detect, $cb; + + defined wantarray + ? bless \$cb, "AnyEvent::Util::postdetect" + : () +} + +sub AnyEvent::Util::postdetect::DESTROY { + @post_detect = grep $_ != ${$_[0]}, @post_detect; +} + +our $POSTPONE_W; +our @POSTPONE; + +sub _postpone_exec { + undef $POSTPONE_W; + + &{ shift @POSTPONE } + while @POSTPONE; +} + +sub postpone(&) { + push @POSTPONE, shift; + + $POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec); + + () +} + +sub log($$;@) { + # only load the big bloated module when we actually are about to log something + if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal + local ($!, $@); + require AnyEvent::Log; # among other things, sets $VERBOSE to 9 + # AnyEvent::Log overwrites this function + goto &log; + } + + 0 # not logged +} + +sub _logger($;$) { + my ($level, $renabled) = @_; + + $$renabled = $level <= $VERBOSE; + + my $logger = [(caller)[0], $level, $renabled]; + + $AnyEvent::Log::LOGGER{$logger+0} = $logger; + +# return unless defined wantarray; +# +# require AnyEvent::Util; +# my $guard = AnyEvent::Util::guard (sub { +# # "clean up" +# delete $LOGGER{$logger+0}; +# }); +# +# sub { +# return 0 unless $$renabled; +# +# $guard if 0; # keep guard alive, but don't cause runtime overhead +# require AnyEvent::Log unless $AnyEvent::Log::VERSION; +# package AnyEvent::Log; +# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time +# } +} + +if (length $ENV{PERL_ANYEVENT_LOG}) { + require AnyEvent::Log; # AnyEvent::Log does the thing for us +} + +our @models = ( + [EV:: => AnyEvent::Impl::EV::], + [AnyEvent::Loop:: => AnyEvent::Impl::Perl::], # everything below here will not (normally) be autoprobed - # as the pureperl backend should work everywhere + # as the pure perl backend should work everywhere # and is usually faster - [Event:: => AnyEvent::Impl::Event::, 1], - [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers + [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top + [Event:: => AnyEvent::Impl::Event::], # slow, stable + [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers + # everything below here should not be autoloaded [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy - [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles [Qt:: => AnyEvent::Impl::Qt::], # requires special main program [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza [Wx:: => AnyEvent::Impl::POE::], [Prima:: => AnyEvent::Impl::POE::], - # IO::Async is just too broken - we would need workarounds for its - # byzantine signal and broken child handling, among others. - # IO::Async is rather hard to detect, as it doesn't have any - # obvious default class. - [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program - [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program - [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program - [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program + [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect + [Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::], + [FLTK:: => AnyEvent::Impl::FLTK::], ); -our %method = map +($_ => 1), - qw(io timer time now now_update signal child idle condvar one_event DESTROY); +our @isa_hook; -our @post_detect; +sub _isa_set { + my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL); -sub post_detect(&) { - my ($cb) = @_; + @{"$pkg[$_-1]::ISA"} = $pkg[$_] + for 1 .. $#pkg; - if ($MODEL) { - $cb->(); + grep $_ && $_->[1], @isa_hook + and AE::_reset (); +} - undef - } else { - push @post_detect, $cb; +# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy +sub _isa_hook($$;$) { + my ($i, $pkg, $reset_ae) = @_; - defined wantarray - ? bless \$cb, "AnyEvent::Util::postdetect" - : () - } -} + $isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef; -sub AnyEvent::Util::postdetect::DESTROY { - @post_detect = grep $_ != ${$_[0]}, @post_detect; + _isa_set; } +# all autoloaded methods reserve the complete glob, not just the method slot. +# due to bugs in perls method cache implementation. +our @methods = qw(io timer time now now_update signal child idle condvar); + sub detect() { - unless ($MODEL) { - local $SIG{__DIE__}; + return $MODEL if $MODEL; # some programs keep references to detect - if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { - my $model = "AnyEvent::Impl::$1"; - if (eval "require $model") { - $MODEL = $model; - warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2; - } else { - warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE; + # IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it + # the author knows about the problems and what it does to AnyEvent as a whole + # (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent + # anyway. + AnyEvent::log fatal => "IO::Async::Loop::AnyEvent detected - that module is broken by\n" + . "design, abuses internals and breaks AnyEvent - will not continue." + if exists $INC{"IO/Async/Loop/AnyEvent.pm"}; + + local $!; # for good measure + local $SIG{__DIE__}; # we use eval + + # free some memory + *detect = sub () { $MODEL }; + # undef &func doesn't correctly update the method cache. grmbl. + # so we delete the whole glob. grmbl. + # otoh, perl doesn't let me undef an active usb, but it lets me free + # a glob with an active sub. hrm. i hope it works, but perl is + # usually buggy in this department. sigh. + delete @{"AnyEvent::"}{@methods}; + undef @methods; + + if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) { + my $model = $1; + $model = "AnyEvent::Impl::$model" unless $model =~ s/::$//; + if (eval "require $model") { + AnyEvent::log 7 => "Loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it."; + $MODEL = $model; + } else { + AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@"; + } + } + + # check for already loaded models + unless ($MODEL) { + for (@REGISTRY, @models) { + my ($package, $model) = @$_; + if (${"$package\::VERSION"} > 0) { + if (eval "require $model") { + AnyEvent::log 7 => "Autodetected model '$model', using it."; + $MODEL = $model; + last; + } else { + AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@"; + } } } - # check for already loaded models unless ($MODEL) { + # try to autoload a model for (@REGISTRY, @models) { my ($package, $model) = @$_; - if (${"$package\::VERSION"} > 0) { - if (eval "require $model") { - $MODEL = $model; - warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2; - last; - } + if ( + eval "require $package" + and ${"$package\::VERSION"} > 0 + and eval "require $model" + ) { + AnyEvent::log 7 => "Autoloaded model '$model', using it."; + $MODEL = $model; + last; } } - unless ($MODEL) { - # try to autoload a model - for (@REGISTRY, @models) { - my ($package, $model, $autoload) = @$_; - if ( - $autoload - and eval "require $package" - and ${"$package\::VERSION"} > 0 - and eval "require $model" - ) { - $MODEL = $model; - warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2; - last; - } - } - - $MODEL - or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; - } + $MODEL + or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?"; } + } - push @{"$MODEL\::ISA"}, "AnyEvent::Base"; + # free memory only needed for probing + undef @models; + undef @REGISTRY; + + push @{"$MODEL\::ISA"}, "AnyEvent::Base"; + + # now nuke some methods that are overridden by the backend. + # SUPER usage is not allowed in these. + for (qw(time signal child idle)) { + undef &{"AnyEvent::Base::$_"} + if defined &{"$MODEL\::$_"}; + } - unshift @ISA, $MODEL; + _isa_set; - require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT}; + # we're officially open! - (shift @post_detect)->() while @post_detect; + if ($ENV{PERL_ANYEVENT_STRICT}) { + require AnyEvent::Strict; } - $MODEL -} + if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) { + require AnyEvent::Debug; + AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP}); + } -sub AUTOLOAD { - (my $func = $AUTOLOAD) =~ s/.*://; + if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) { + require AnyEvent::Socket; + require AnyEvent::Debug; - $method{$func} - or Carp::croak "$func: not a valid method for AnyEvent objects"; + my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL}; + $shell =~ s/\$\$/$$/g; - detect unless $MODEL; + my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell); + $AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service); + } - my $class = shift; - $class->$func (@_); + # now the anyevent environment is set up as the user told us to, so + # call the actual user code - post detects + + (shift @post_detect)->() while @post_detect; + undef @post_detect; + + *post_detect = sub(&) { + shift->(); + + undef + }; + + $MODEL +} + +for my $name (@methods) { + *$name = sub { + detect; + # we use goto because + # a) it makes the thunk more transparent + # b) it allows us to delete the thunk later + goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" } + }; } # utility function to dup a filehandle. this is used by many backends @@ -1295,7 +1552,7 @@ Starting with version 5.0, AnyEvent officially supports a second, much simpler, API that is designed to reduce the calling, typing and memory -overhead. +overhead by using function call syntax and a fixed number of parameters. See the L manpage for details. @@ -1305,68 +1562,103 @@ our $VERSION = $AnyEvent::VERSION; -sub io($$$) { - AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2]) -} +sub _reset() { + eval q{ + # fall back to the main API by default - backends and AnyEvent::Base + # implementations can overwrite these. -sub timer($$$) { - AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]) -} + sub io($$$) { + AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2]) + } -sub signal($$) { - AnyEvent->signal (signal => $_[0], cb => $_[1]) -} + sub timer($$$) { + AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]) + } -sub child($$) { - AnyEvent->child (pid => $_[0], cb => $_[1]) -} + sub signal($$) { + AnyEvent->signal (signal => $_[0], cb => $_[1]) + } -sub idle($) { - AnyEvent->idle (cb => $_[0]) -} + sub child($$) { + AnyEvent->child (pid => $_[0], cb => $_[1]) + } -sub cv(;&) { - AnyEvent->condvar (@_ ? (cb => $_[0]) : ()) -} + sub idle($) { + AnyEvent->idle (cb => $_[0]); + } -sub now() { - AnyEvent->now -} + sub cv(;&) { + AnyEvent->condvar (@_ ? (cb => $_[0]) : ()) + } -sub now_update() { - AnyEvent->now_update -} + sub now() { + AnyEvent->now + } + + sub now_update() { + AnyEvent->now_update + } + + sub time() { + AnyEvent->time + } -sub time() { - AnyEvent->time + *postpone = \&AnyEvent::postpone; + *log = \&AnyEvent::log; + }; + die if $@; } +BEGIN { _reset } + package AnyEvent::Base; # default implementations for many methods -sub _time { - # probe for availability of Time::HiRes - if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { - warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; - *_time = \&Time::HiRes::time; - # if (eval "use POSIX (); (POSIX::times())... - } else { - warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; - *_time = sub { time }; # epic fail - } +sub time { + eval q{ # poor man's autoloading {} + # probe for availability of Time::HiRes + if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { + *time = sub { Time::HiRes::time () }; + *AE::time = \& Time::HiRes::time ; + *now = \&time; + AnyEvent::log 8 => "using Time::HiRes for sub-second timing accuracy."; + # if (eval "use POSIX (); (POSIX::times())... + } else { + *time = sub { CORE::time }; + *AE::time = sub (){ CORE::time }; + *now = \&time; + AnyEvent::log 3 => "Using built-in time(), no sub-second resolution!"; + } + }; + die if $@; - &_time + &time } -sub time { _time } -sub now { _time } +*now = \&time; sub now_update { } +sub _poll { + Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught"; +} + # default implementation for ->condvar +# in fact, the default should not be overwritten sub condvar { - bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" + eval q{ # poor man's autoloading {} + *condvar = sub { + bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" + }; + + *AE::cv = sub (;&) { + bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar" + }; + }; + die if $@; + + &condvar } # default implementation for ->signal @@ -1375,7 +1667,7 @@ sub _have_async_interrupt() { $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} - && eval "use Async::Interrupt 1.0 (); 1") + && eval "use Async::Interrupt 1.02 (); 1") unless defined $HAVE_ASYNC_INTERRUPT; $HAVE_ASYNC_INTERRUPT @@ -1385,20 +1677,8 @@ our (%SIG_ASY, %SIG_ASY_W); our ($SIG_COUNT, $SIG_TW); -sub _signal_exec { - $HAVE_ASYNC_INTERRUPT - ? $SIGPIPE_R->drain - : sysread $SIGPIPE_R, my $dummy, 9; - - while (%SIG_EV) { - for (keys %SIG_EV) { - delete $SIG_EV{$_}; - $_->() for values %{ $SIG_CB{$_} || {} }; - } - } -} - # install a dummy wakeup watcher to reduce signal catching latency +# used by Impls sub _sig_add() { unless ($SIG_COUNT++) { # try to align timer on a full-second boundary, if possible @@ -1418,7 +1698,7 @@ } our $_sig_name_init; $_sig_name_init = sub { - eval q{ # poor man's autoloading + eval q{ # poor man's autoloading {} undef $_sig_name_init; if (_have_async_interrupt) { @@ -1452,15 +1732,13 @@ eval q{ # poor man's autoloading {} # probe for availability of Async::Interrupt if (_have_async_interrupt) { - warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8; + AnyEvent::log 8 => "Using Async::Interrupt for race-free signal handling."; $SIGPIPE_R = new Async::Interrupt::EventPipe; $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec; } else { - warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8; - - require Fcntl; + AnyEvent::log 8 => "Using emulated perl signal handling with latency timer."; if (AnyEvent::WIN32) { require AnyEvent::Util; @@ -1470,12 +1748,12 @@ AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case } else { pipe $SIGPIPE_R, $SIGPIPE_W; - fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; - fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case + fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R; + fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case # not strictly required, as $^F is normally 2, but let's make sure... - fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; - fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; + fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC; + fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC; } $SIGPIPE_R @@ -1484,45 +1762,43 @@ $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec; } - *signal = sub { - my (undef, %arg) = @_; - - my $signal = uc $arg{signal} - or Carp::croak "required option 'signal' is missing"; - - if ($HAVE_ASYNC_INTERRUPT) { - # async::interrupt - - $signal = sig2num $signal; - $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; - - $SIG_ASY{$signal} ||= new Async::Interrupt - cb => sub { undef $SIG_EV{$signal} }, - signal => $signal, - pipe => [$SIGPIPE_R->filenos], - pipe_autodrain => 0, - ; + *signal = $HAVE_ASYNC_INTERRUPT + ? sub { + my (undef, %arg) = @_; + + # async::interrupt + my $signal = sig2num $arg{signal}; + $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; + + $SIG_ASY{$signal} ||= new Async::Interrupt + cb => sub { undef $SIG_EV{$signal} }, + signal => $signal, + pipe => [$SIGPIPE_R->filenos], + pipe_autodrain => 0, + ; + + bless [$signal, $arg{cb}], "AnyEvent::Base::signal" + } + : sub { + my (undef, %arg) = @_; + + # pure perl + my $signal = sig2name $arg{signal}; + $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; + + $SIG{$signal} ||= sub { + local $!; + syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; + undef $SIG_EV{$signal}; + }; + + # can't do signal processing without introducing races in pure perl, + # so limit the signal latency. + _sig_add; - } else { - # pure perl - - # AE::Util has been loaded in signal - $signal = sig2name $signal; - $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; - - $SIG{$signal} ||= sub { - local $!; - syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; - undef $SIG_EV{$signal}; - }; - - # can't do signal processing without introducing races in pure perl, - # so limit the signal latency. - _sig_add; - } - - bless [$signal, $arg{cb}], "AnyEvent::Base::signal" - }; + bless [$signal, $arg{cb}], "AnyEvent::Base::signal" + } + ; *AnyEvent::Base::signal::DESTROY = sub { my ($signal, $cb) = @{$_[0]}; @@ -1539,8 +1815,22 @@ undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; }; + + *_signal_exec = sub { + $HAVE_ASYNC_INTERRUPT + ? $SIGPIPE_R->drain + : sysread $SIGPIPE_R, (my $dummy), 9; + + while (%SIG_EV) { + for (keys %SIG_EV) { + delete $SIG_EV{$_}; + &$_ for values %{ $SIG_CB{$_} || {} }; + } + } + }; }; die if $@; + &signal } @@ -1549,8 +1839,8 @@ our %PID_CB; our $CHLD_W; our $CHLD_DELAY_W; -our $WNOHANG; +# used by many Impl's sub _emit_childstatus($$) { my (undef, $rpid, $rstatus) = @_; @@ -1559,84 +1849,99 @@ values %{ $PID_CB{0} || {} }; } -sub _sigchld { - my $pid; +sub child { + eval q{ # poor man's autoloading {} + *_sigchld = sub { + my $pid; - AnyEvent->_emit_childstatus ($pid, $?) - while ($pid = waitpid -1, $WNOHANG) > 0; -} + AnyEvent->_emit_childstatus ($pid, $?) + while ($pid = waitpid -1, WNOHANG) > 0; + }; -sub child { - my (undef, %arg) = @_; + *child = sub { + my (undef, %arg) = @_; - defined (my $pid = $arg{pid} + 0) - or Carp::croak "required option 'pid' is missing"; + my $pid = $arg{pid}; + my $cb = $arg{cb}; - $PID_CB{$pid}{$arg{cb}} = $arg{cb}; + $PID_CB{$pid}{$cb+0} = $cb; - # WNOHANG is almost cetrainly 1 everywhere - $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/ - ? 1 - : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; - - unless ($CHLD_W) { - $CHLD_W = AE::signal CHLD => \&_sigchld; - # child could be a zombie already, so make at least one round - &_sigchld; - } + unless ($CHLD_W) { + $CHLD_W = AE::signal CHLD => \&_sigchld; + # child could be a zombie already, so make at least one round + &_sigchld; + } - bless [$pid, $arg{cb}], "AnyEvent::Base::child" -} + bless [$pid, $cb+0], "AnyEvent::Base::child" + }; -sub AnyEvent::Base::child::DESTROY { - my ($pid, $cb) = @{$_[0]}; + *AnyEvent::Base::child::DESTROY = sub { + my ($pid, $icb) = @{$_[0]}; - delete $PID_CB{$pid}{$cb}; - delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; + delete $PID_CB{$pid}{$icb}; + delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; - undef $CHLD_W unless keys %PID_CB; + undef $CHLD_W unless keys %PID_CB; + }; + }; + die if $@; + + &child } # idle emulation is done by simply using a timer, regardless # of whether the process is idle or not, and not letting # the callback use more than 50% of the time. sub idle { - my (undef, %arg) = @_; + eval q{ # poor man's autoloading {} + *idle = sub { + my (undef, %arg) = @_; - my ($cb, $w, $rcb) = $arg{cb}; + my ($cb, $w, $rcb) = $arg{cb}; - $rcb = sub { - if ($cb) { - $w = _time; - &$cb; - $w = _time - $w; - - # never use more then 50% of the time for the idle watcher, - # within some limits - $w = 0.0001 if $w < 0.0001; - $w = 5 if $w > 5; + $rcb = sub { + if ($cb) { + $w = AE::time; + &$cb; + $w = AE::time - $w; + + # never use more then 50% of the time for the idle watcher, + # within some limits + $w = 0.0001 if $w < 0.0001; + $w = 5 if $w > 5; + + $w = AE::timer $w, 0, $rcb; + } else { + # clean up... + undef $w; + undef $rcb; + } + }; - $w = AE::timer $w, 0, $rcb; - } else { - # clean up... - undef $w; - undef $rcb; - } - }; + $w = AE::timer 0.05, 0, $rcb; - $w = AE::timer 0.05, 0, $rcb; + bless \\$cb, "AnyEvent::Base::idle" + }; - bless \\$cb, "AnyEvent::Base::idle" -} + *AnyEvent::Base::idle::DESTROY = sub { + undef $${$_[0]}; + }; + }; + die if $@; -sub AnyEvent::Base::idle::DESTROY { - undef $${$_[0]}; + &idle } package AnyEvent::CondVar; our @ISA = AnyEvent::CondVar::Base::; +# only to be used for subclassing +sub new { + my $class = shift; + bless AnyEvent->condvar (@_), $class +} + package AnyEvent::CondVar::Base; #use overload @@ -1655,6 +1960,10 @@ # nop } +sub _wait { + AnyEvent->_poll until $_[0]{_ae_sent}; +} + sub send { my $cv = shift; $cv->{_ae_sent} = [@_]; @@ -1671,20 +1980,21 @@ $_[0]{_ae_sent} } -sub _wait { - $WAITING - and !$_[0]{_ae_sent} - and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected"; +sub recv { + unless ($_[0]{_ae_sent}) { + $WAITING + and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted"; - local $WAITING = 1; - AnyEvent->one_event while !$_[0]{_ae_sent}; -} + local $WAITING = 1; + $_[0]->_wait; + } -sub recv { - $_[0]->_wait; + $_[0]{_ae_croak} + and Carp::croak $_[0]{_ae_croak}; - Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; - wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] + wantarray + ? @{ $_[0]{_ae_sent} } + : $_[0]{_ae_sent}[0] } sub cb { @@ -1710,7 +2020,7 @@ # undocumented/compatibility with pre-3.4 *broadcast = \&send; -*wait = \&_wait; +*wait = \&recv; =head1 ERROR AND EXCEPTION HANDLING @@ -1732,30 +2042,88 @@ =head1 ENVIRONMENT VARIABLES -The following environment variables are used by this module or its -submodules. +AnyEvent supports a number of environment variables that tune the +runtime behaviour. They are usually evaluated when AnyEvent is +loaded, initialised, or a submodule that uses them is loaded. Many of +them also cause AnyEvent to load additional modules - for example, +C causes the L module to be +loaded. + +All the environment variables documented here start with +C, which is what AnyEvent considers its own +namespace. Other modules are encouraged (but by no means required) to use +C if they have registered the AnyEvent::Submodule +namespace on CPAN, for any submodule. For example, L could +be expected to use C (it should not access env +variables starting with C, see below). + +All variables can also be set via the C prefix, that is, instead +of setting C you can also set C. In +case there is a clash btween anyevent and another program that uses +C you can set the corresponding C +variable to the empty string, as those variables take precedence. + +When AnyEvent is first loaded, it copies all C env variables +to their C counterpart unless that variable already +exists. If taint mode is on, then AnyEvent will remove I environment +variables starting with C from C<%ENV> (or replace them +with C or the empty string, if the corresaponding C variable +is set). + +The exact algorithm is currently: + + 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV + 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists + 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef. -Note that AnyEvent will remove I environment variables starting with -C from C<%ENV> when it is loaded while taint mode is -enabled. +This ensures that child processes will not see the C variables. + +The following environment variables are currently known to AnyEvent: =over 4 =item C -By default, AnyEvent will be completely silent except in fatal -conditions. You can set this environment variable to make AnyEvent more -talkative. +By default, AnyEvent will log messages with loglevel C<4> (C) or +higher (see L). You can set this environment variable to a +numerical loglevel to make AnyEvent more (or less) talkative. + +If you want to do more than just set the global logging level +you should have a look at C, which allows much more +complex specifications. + +When set to C<0> (C), then no messages whatsoever will be logged with +everything else at defaults. -When set to C<1> or higher, causes AnyEvent to warn about unexpected +When set to C<5> or higher (C), AnyEvent warns about unexpected conditions, such as not being able to load the event model specified by -C. +C, or a guard callback throwing an exception - this +is the minimum recommended level for use during development. + +When set to C<7> or higher (info), AnyEvent reports which event model it +chooses. + +When set to C<8> or higher (debug), then AnyEvent will report extra +information on which optional modules it loads and how it implements +certain features. + +=item C + +Accepts rather complex logging specifications. For example, you could log +all C messages of some module to stderr, warnings and above to +stderr, and errors and above to syslog, with: -When set to C<2> or higher, cause AnyEvent to report to STDERR which event -model it chooses. + PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog -When set to C<8> or higher, then AnyEvent will report extra information on -which optional modules it loads and how it implements certain features. +For the rather extensive details, see L. + +This variable is evaluated when AnyEvent (or L) is loaded, +so will take effect even before AnyEvent has initialised itself. + +Note that specifying this environment variable causes the L +module to be loaded, while C does not, so only +using the latter saves a few hundred kB of memory unless a module +explicitly needs the extra features of AnyEvent::Log. =item C @@ -1767,27 +2135,67 @@ In other words, enables "strict" mode. -Unlike C (or it's modern cousin, C<< use L +Unlike C (or its modern cousin, C<< use L >>, it is definitely recommended to keep it off in production. Keeping C in your environment while developing programs can be very useful, however. +=item C + +If this env variable is nonempty, then its contents will be interpreted by +C and C (after +replacing every occurance of C<$$> by the process pid). The shell object +is saved in C<$AnyEvent::Debug::SHELL>. + +This happens when the first watcher is created. + +For example, to bind a debug shell on a unix domain socket in +F<< /tmp/debug.sock >>, you could use this: + + PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog + # connect with e.g.: socat readline /tmp/debug123.sock + +Or to bind to tcp port 4545 on localhost: + + PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog + # connect with e.g.: telnet localhost 4545 + +Note that creating sockets in F or on localhost is very unsafe on +multiuser systems. + +=item C + +Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for +debugging purposes. See C for details. + =item C This can be used to specify the event model to be used by AnyEvent, before -auto detection and -probing kicks in. It must be a string consisting -entirely of ASCII letters. The string C gets prepended -and the resulting module name is loaded and if the load was successful, -used as event model. If it fails to load AnyEvent will proceed with +auto detection and -probing kicks in. + +It normally is a string consisting entirely of ASCII letters (e.g. C +or C). The string C gets prepended and the +resulting module name is loaded and - if the load was successful - used as +event model backend. If it fails to load then AnyEvent will proceed with auto detection and -probing. -This functionality might change in future versions. +If the string ends with C<::> instead (e.g. C) then +nothing gets prepended and the module name is used as-is (hint: C<::> at +the end of a string designates a module name and quotes it appropriately). -For example, to force the pure perl model (L) you +For example, to force the pure perl model (L) you could start your program like this: PERL_ANYEVENT_MODEL=Perl perl ... +=item C + +The current file I/O model - see L for more info. + +At the moment, only C (small, pure-perl, synchronous) and +C (truly asynchronous) are supported. The default is C if +L can be loaded, otherwise it is C. + =item C Used by both L and L to determine preferences @@ -1809,12 +2217,18 @@ addresses. C support either IPv4 or IPv6, but prefer IPv6 over IPv4. +=item C + +This variable, if specified, overrides the F file used by +LC<::resolve_sockaddr>, i.e. hosts aliases will be read +from that file instead. + =item C -Used by L to decide whether to use the EDNS0 extension -for DNS. This extension is generally useful to reduce DNS traffic, but -some (broken) firewalls drop such DNS packets, which is why it is off by -default. +Used by L to decide whether to use the EDNS0 extension for +DNS. This extension is generally useful to reduce DNS traffic, especially +when DNSSEC is involved, but some (broken) firewalls drop such DNS +packets, which is why it is off by default. Setting this variable to C<1> will cause L to announce EDNS0 in its DNS requests. @@ -1830,18 +2244,40 @@ resolver - this is the maximum number of parallel DNS requests that are sent to the DNS server. +=item C + +Perl has inherently racy signal handling (you can basically choose between +losing signals and memory corruption) - pure perl event loops (including +C, when C isn't available) therefore +have to poll regularly to avoid losing signals. + +Some event loops are racy, but don't poll regularly, and some event loops +are written in C but are still racy. For those event loops, AnyEvent +installs a timer that regularly wakes up the event loop. + +By default, the interval for this timer is C<10> seconds, but you can +override this delay with this environment variable (or by setting +the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal +watchers). + +Lower values increase CPU (and energy) usage, higher values can introduce +long delays when reaping children or waiting for signals. + +The L module, if available, will be used to avoid this +polling (with most event loops). + =item C -The file to use instead of F (or OS-specific -configuration) in the default resolver. When set to the empty string, no -default config will be used. +The absolute path to a F-style file to use instead of +F (or the OS-specific configuration) in the default +resolver, or the empty string to select the default configuration. =item C, C. When neither C nor C was specified during L context creation, and either of these environment -variables exist, they will be used to specify CA certificate locations -instead of a system-dependent default. +variables are nonempty, they will be used to specify CA certificate +locations instead of a system-dependent default. =item C and C @@ -1914,16 +2350,9 @@ }, ); - my $time_watcher; # can only be used once - - sub new_timer { - $timer = AnyEvent->timer (after => 1, cb => sub { - warn "timeout\n"; # print 'timeout' about every second - &new_timer; # and restart the time - }); - } - - new_timer; # create first timer + my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub { + warn "timeout\n"; # print 'timeout' at most every second + }); $cv->recv; # wait until user enters /^q/i @@ -2006,7 +2435,7 @@ that occurred during request processing. The C method detects whether an exception as thrown (it is stored inside the $txn object) and just throws the exception, which means connection errors and other -problems get reported tot he code that tries to use the result, not in a +problems get reported to the code that tries to use the result, not in a random callback. All of this enables the following usage styles: @@ -2190,7 +2619,7 @@ =item * The overhead AnyEvent adds is usually much smaller than the overhead of the actual event loop, only with extremely fast event loops such as EV -adds AnyEvent significant overhead. +does AnyEvent add significant overhead. =item * You should avoid POE like the plague if you want performance or reasonable memory usage. @@ -2377,13 +2806,13 @@ backend easily beats IO::Lambda and POE. And even the 100% non-blocking version written using the high-level (and -slow :) L abstraction beats both POE and IO::Lambda by a -large margin, even though it does all of DNS, tcp-connect and socket I/O -in a non-blocking way. +slow :) L abstraction beats both POE and IO::Lambda +higher level ("unoptimised") abstractions by a large margin, even though +it does all of DNS, tcp-connect and socket I/O in a non-blocking way. The two AnyEvent benchmarks programs can be found as F and F in the AnyEvent distribution, the remaining benchmarks are -part of the IO::lambda distribution and were used without any changes. +part of the IO::Lambda distribution and were used without any changes. =head1 SIGNALS @@ -2430,13 +2859,13 @@ =head1 RECOMMENDED/OPTIONAL MODULES One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and -it's built-in modules) are required to use it. +its built-in modules) are required to use it. That does not mean that AnyEvent won't take advantage of some additional modules if they are installed. -This section epxlains which additional modules will be used, and how they -affect AnyEvent's operetion. +This section explains which additional modules will be used, and how they +affect AnyEvent's operation. =over 4 @@ -2451,7 +2880,7 @@ If this module is available, then it will be used to implement signal catching, which means that signals will not be delayed, and the event loop -will not be interrupted regularly, which is more efficient (And good for +will not be interrupted regularly, which is more efficient (and good for battery life on laptops). This affects not just the pure-perl event loop, but also other event loops @@ -2473,6 +2902,9 @@ C, and is the fastest backend I. You can even embed L/L in it (or vice versa, see L and L). +If you only use backends that rely on another event loop (e.g. C), +then this module will do nothing for you. + =item L The guard module, when used, will be used to implement @@ -2482,13 +2914,10 @@ =item L and L -This module is required when you want to read or write JSON data via -L. It is also written in pure-perl, but can take +One of these modules is required when you want to read or write JSON data +via L. L is also written in pure-perl, but can take advantage of the ultra-high-speed L module when it is installed. -In fact, L will use L by default if it is -installed. - =item L Implementing TLS/SSL in Perl is certainly interesting, but not very @@ -2498,8 +2927,8 @@ =item L This module is part of perl since release 5.008. It will be used when the -chosen event library does not come with a timing source on it's own. The -pure-perl event loop (L) will additionally use it to +chosen event library does not come with a timing source of its own. The +pure-perl event loop (L) will additionally load it to try to use a monotonic clock for timing stability. =back @@ -2508,13 +2937,31 @@ =head1 FORK Most event libraries are not fork-safe. The ones who are usually are -because they rely on inefficient but fork-safe C or C calls +- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll +are usually badly thought-out hacks that are incompatible with fork in +one way or another. Only L is fully fork-aware and ensures that you +continue event-processing in both parent and child (or both, if you know +what you are doing). + +This means that, in general, you cannot fork and do event processing in +the child if the event library was initialised before the fork (which +usually happens when the first AnyEvent watcher is created, or the library +is loaded). If you have to fork, you must either do so I creating your first watcher OR you must not use AnyEvent at all in the child OR you must do something completely out of the scope of AnyEvent. +The problem of doing event processing in the parent I the child +is much more complicated: even for backends that I fork-aware or +fork-safe, their behaviour is not usually what you want: fork clones all +watchers, that means all timers, I/O watchers etc. are active in both +parent and child, which is almost never what you want. USing C +to start worker children from some kind of manage rprocess is usually +preferred, because it is much easier and cleaner, at the expense of having +to have another binary. + =head1 SECURITY CONSIDERATIONS @@ -2553,32 +3000,43 @@ =head1 SEE ALSO -Utility functions: L. +Tutorial/Introduction: L. -Event modules: L, L, L, L, L, -L, L, L, L, L. +FAQ: L. + +Utility functions: L (misc. grab-bag), L +(simply logging). + +Development/Debugging: L (stricter checking), +L (interactive shell, watcher tracing). + +Supported event modules: L, L, L, +L, L, L, L, L, L, +L, L, L. Implementations: L, L, L, L, L, L, L, -L, L, L. +L, L, L, +L. -Non-blocking file handles, sockets, TCP clients and +Non-blocking handles, pipes, stream sockets, TCP clients and servers: L, L, L. +Asynchronous File I/O: L. + Asynchronous DNS: L. -Coroutine support: L, L, L, -L, +Thread support: L, L, L, L. -Nontrivial usage examples: L, L, +Nontrivial usage examples: L, L, L. =head1 AUTHOR Marc Lehmann - http://home.schmorp.de/ + http://anyevent.schmorp.de =cut