--- EV/Makefile.PL	2010/12/30 07:43:03	1.50
+++ EV/Makefile.PL	2020/02/18 18:26:47	1.68
@@ -1,10 +1,15 @@
-use 5.008002;
-
 use strict qw(vars subs);
+use Canary::Stability EV => 1, 5.008002;
 use Config;
 use ExtUtils::MakeMaker;
 
-unless (-e "libev/ev_epoll.c") {
+sub have_inc($) {
+   scalar grep -r "$_/$_[0]", $Config{usrinc}, split / /, $Config{incpth}
+}
+
+my $DEFINE;
+
+unless (-e "libev/ev_iouring.c") {
    print <<EOF;
 
 ***
@@ -46,7 +51,9 @@
 
 EOF
 
-my $DEFINE .= " -DEV_USE_MONOTONIC=" . (0 + (prompt ("Enable optional support for CLOCK_MONOTONIC (y/n)?", "y") =~ /[yY]/));
+unless (prompt ("Enable optional support for CLOCK_MONOTONIC (y/n)?", "y") =~ /[yY]/) {
+   $DEFINE .= " -DEV_USE_MONOTONIC=0";
+}
 
 print <<EOF;
 
@@ -95,10 +102,10 @@
 
    if (prompt ("Force use of system fd_set for select backend (y/n)?", "n") =~ /[yY]/) {
       $DEFINE .= " -DEV_SELECT_USE_FD_SET";
-   } 
+   }
 } else {
    $DEFINE .= " -DEV_USE_SELECT=0";
-} 
+}
 
 print <<EOF;
 
@@ -108,11 +115,11 @@
 The second very portable backend is poll(2). It does not exist on windows
 and various versions of Mac OS X (and on the other versions it simply
 doesn't work), but works basically everywhere else. It is recommended to use
-the default here unless you run into compile problems in ev_poll.c.
+the default here unless you run into compilation problems in ev_poll.c.
 
 EOF
 
-$DEFINE .= " -DEV_USE_POLL=" . (0 + (prompt ("Enable poll backend (y/n)?", (-e "/usr/include/poll.h") ? "y" : "n") =~ /[yY]/));
+$DEFINE .= " -DEV_USE_POLL=" . (0 + (prompt ("Enable poll backend (y/n)?", (have_inc "poll.h") ? "y" : "n") =~ /[yY]/));
 
 print <<EOF;
 
@@ -129,7 +136,7 @@
 
 EOF
 
-my $can_epoll = -e "/usr/include/sys/epoll.h";
+my $can_epoll = have_inc "sys/epoll.h";
 $can_epoll = $ENV{EV_EPOLL} if exists $ENV{EV_EPOLL};
 $DEFINE .= " -DEV_USE_EPOLL=" . (0 + (prompt ("Enable epoll backend (y/n)?", $can_epoll ? "y" : "n") =~ /[yY]/));
 
@@ -138,13 +145,96 @@
 *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
 
 
-Similarly to the epoll backend above, EV can take advantage of kqueue on
-many BSD systems. Support for kqueue will be detected at runtime, with a
-safe fallback to other methods when it cannot be used.
-
-Note that kqueue is broken on most operating systems, so by default it
-won't be used on many platforms, but you can still create your own event
-loop with kqueue backend if you ask specifically for it.
+Linux 4.18 introduced another event polling interface, this time using
+the Linux AIO API. While this API is far superior to epoll and almost
+rivals kqueue, it also suffers from the same issues as kqueue typically
+does: only a subset of file types are supported (as of 4.19, I have seen
+eventfd, pipes, sockets files and some devices, but no ttys). It also
+is subject arbitrary system-wide limits imposed on it. Therefore, this
+backend is not used by default, even when it is compiled in, and you have
+to request it explicitly, e.g. with LIBEV_FLAGS=64. If unsure, accept the
+default.
+
+EOF
+
+my $can_linuxaio = have_inc "linux/aio_abi.h";
+$can_linuxaio = $ENV{EV_LINUXAIO} if exists $ENV{EV_LINUXAIO};
+$can_linuxaio = 0 + (prompt ("Enable linux aio backend (y/n)?", $can_linuxaio ? "y" : "n") =~ /[yY]/);
+$DEFINE .= " -DEV_USE_LINUXAIO=$can_linuxaio";
+
+if ($can_linuxaio) {
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+The previously mentioned Linux AIO backend is experimental and will not
+be used unless requested explicitly. You can, howeer, choose to make ti a
+recommended basckend, which means it will be chosen if available even when
+not explicitly asked for, in preference to epoll on GNU/Linux. This option
+is likely temporary. When unsure, accept the default.
+
+EOF
+
+my $recommend_linuxaio = 0;
+$recommend_linuxaio = $ENV{EV_RECOMMEND_LINUXAIO} if exists $ENV{EV_RECOMMEND_LINUXAIO};
+$recommend_linuxaio = 0 + (prompt ("Treat linux aio as a recommended backend (y/n)?", $recommend_linuxaio ? "y" : "n") =~ /[yY]/);
+$DEFINE .= " -DEV_RECOMMEND_LINUXAIO=$recommend_linuxaio";
+}
+
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+Linux 4.19 introduced another event polling interface, "io_uring". While
+this API is far superior to epoll and almost rivals linuxaio, it also
+suffers from the same issues as kqueue typically does: only a subset of
+file types are supported (as of 5.2). It is also very buggy still, and
+most importantly, very very slow for most workloads.  Therefore, this
+backend is not used by default, even when it is compiled in, and you have
+to request it explicitly, e.g. with LIBEV_FLAGS=128. If unsure, accept the
+default.
+
+EOF
+
+my $can_iouring = have_inc "linux/fs.h";
+$can_iouring = $ENV{EV_IOURING} if exists $ENV{EV_IOURING};
+$can_iouring = 0 + (prompt ("Enable linux io_uring backend (y/n)?", $can_iouring ? "y" : "n") =~ /[yY]/);
+$DEFINE .= " -DEV_USE_IOURING=$can_iouring";
+
+if ($can_iouring) {
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+The previously mentioned Linux io_uring is experimental and will not be
+used unless requested explicitly. You can, howeer, choose to make ti a
+recommended basckend, which means it will be chosen if available even when
+not explicitly asked for, in preference to epoll on GNU/Linux. This option
+is likely temporary. When unsure, accept the default.
+
+EOF
+
+my $recommend_iouring = 0;
+$recommend_iouring = $ENV{EV_RECOMMEND_IOURING} if exists $ENV{EV_RECOMMEND_IOURING};
+$recommend_iouring = 0 + (prompt ("Treat io_uring as a recommended backend (y/n)?", $recommend_iouring ? "y" : "n") =~ /[yY]/);
+$DEFINE .= " -DEV_RECOMMEND_IOURING=$recommend_iouring";
+}
+
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+EV can take advantage of kqueue on many BSD systems. Support for kqueue
+will be detected at runtime, with a safe fallback to other methods when it
+cannot be used.
+
+Note that kqueue is subtly broken on most operating systems, so by default
+it won't be used on many platforms, but you can still create your own
+event loop with kqueue backend if you ask specifically for it.
 
 Here is what we know:
 
@@ -157,7 +247,8 @@
 
 EOF
 
-my $can_kqueue = -e "/usr/include/sys/event.h";
+# minix has all the header files, but no implementation. won-der-ful.
+my $can_kqueue = have_inc "sys/event.h" && $^O ne "minix";
 $can_kqueue = $ENV{EV_KQUEUE} if exists $ENV{EV_KQUEUE};
 $DEFINE .= " -DEV_USE_KQUEUE=" . (0 + (prompt ("Enable kqueue backend (y/n)?", $can_kqueue ? "y" : "n") =~ /[yY]/));
 
@@ -172,7 +263,7 @@
 
 EOF
 
-$DEFINE .= " -DEV_USE_PORT=" . (0 + (prompt ("Enable event port backend (y/n)?", (-e "/usr/include/sys/port.h") ? "y" : "n") =~ /[yY]/));
+$DEFINE .= " -DEV_USE_PORT=" . (0 + (prompt ("Enable event port backend (y/n)?", (have_inc "sys/port.h") ? "y" : "n") =~ /[yY]/));
 
 print <<EOF;
 
@@ -184,12 +275,16 @@
 can specify additional libraries to provide these calls (and any other
 required by EV) now, or accept the default.
 
+On GNU/Linux systems, EV uses the LSB 3.1 __register_atfork function
+to avoid the dependency on libpthread, and directly uses the clock_gettime
+syscall to avoid a dependency on librt.
+
 EOF
 
 my $solaris_libs = $^O =~ /solaris/i ? "-lsocket -lnsl" : "";
-#my $librt = $^O =~ /linux/i ? "-lpthread" : "-lpthread -lrt";
-my $librt = "-lpthread -lrt";
-my $LIBS = prompt "Extra libraries for pthread_atfork and clock_gettime?", "$librt $solaris_libs";
+my $librt = $^O =~ /linux/i ? "" : "-lpthread -lrt";
+my $LIBS = exists $ENV{EV_LIBS} ? $ENV{EV_LIBS} : "$librt $solaris_libs";
+$LIBS = prompt "Extra libraries for pthread_atfork and clock_gettime?", $LIBS;
 
 
 print <<EOF;
@@ -204,7 +299,7 @@
 
 EOF
 
-my $can_inotify = -e "/usr/include/sys/inotify.h";
+my $can_inotify = have_inc "sys/inotify.h";
 $can_inotify = $ENV{EV_INOTIFY} if exists $ENV{EV_INOTIFY};
 $DEFINE .= " -DEV_USE_INOTIFY=" . (0 + (prompt ("Enable inotify support (y/n)?", $can_inotify ? "y" : "n") =~ /[yY]/));
 
@@ -221,7 +316,7 @@
 
 EOF
 
-my $can_eventfd = -e "/usr/include/sys/eventfd.h";
+my $can_eventfd = have_inc "sys/eventfd.h";
 $can_eventfd = $ENV{EV_EVENTFD} if exists $ENV{EV_EVENTFD};
 $DEFINE .= " -DEV_USE_EVENTFD=" . (0 + (prompt ("Enable linux eventfd support (y/n)?", $can_eventfd ? "y" : "n") =~ /[yY]/));
 
@@ -237,7 +332,7 @@
 
 EOF
 
-my $can_signalfd = -e "/usr/include/sys/signalfd.h";
+my $can_signalfd = have_inc "sys/signalfd.h";
 $can_signalfd = $ENV{EV_SIGNALFD} if exists $ENV{EV_SIGNALFD};
 $DEFINE .= " -DEV_USE_SIGNALFD=" . (0 + (prompt ("Enable linux signalfd support (y/n)?", $can_signalfd ? "y" : "n") =~ /[yY]/));
 
@@ -246,10 +341,54 @@
 *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
 
 
+Linux kernels can notify userspace about realtime clock timejumps
+using timerfd. Libev by default will try to take advantage of this if
+possible. You can completely disable the detection and use of timerfd for
+this purpose by answering 'n' here. Support for timerfd will otherwise be
+autodetected at both compile- and runtime.
+
+EOF
+
+unless (prompt ("Enable optional support for timerfd to detect timejumps (y/n)?", "y") =~ /[yY]/) {
+   $DEFINE .= " -DEV_USE_TIMERFD=0";
+}
+
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+Libev contains numerous internal assert() invocations to check for
+consistency and user errors. These are normally enabled, but most
+perl builds disable this error reporting mechanism by default. You
+can re-enable these asserts here. Enabling them might help you catch
+programming bugs earlier, but might cause a small slowdown. Also, failures
+will be reported by aboritng your program, instead of throwing a perl
+exception.
+
+If unsure, enable this if you only use this perl installation for
+development, and leave it off for use in production environments.
+
+EOF
+
+my $enable_assertions = 0;
+$enable_assertions = 0 + (prompt ("Make sure assertions are enabled? (y/n)?", $enable_assertions ? "y" : "n") =~ /[yY]/);
+$DEFINE .= " -DEV_ENABLE_ASSERTIONS=1" if $enable_assertions;
+
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
 Very rarely, people want to tweak EV even more, e.g. to exclude
-or incldue certain watcher types or backends. Thisc na be done by adding
+or include certain watcher types or backends. This can be done by adding
 extra -D options here, or via the EV_EXTRA_DEFS environment variable.
-Normal persons just press enter.
+
+For example, if you run into compilation problems because of missing memory
+fences (or you just want extra performance), you can tell EV to not support
+smp and threads via -DEV_NO_THREADS.
+
+Most people would just press enter.
 
 EOF
 
@@ -272,7 +411,7 @@
 	           },
     depend => {
        "EV.c" => "EV/EVAPI.h "
-               . "libev/ev.c libev/ev.h libev/ev_epoll.c libev/ev_select.c libev/ev_kqueue.c libev/ev_poll.c "
+               . "libev/ev.c libev/ev.h libev/ev_epoll.c libev/ev_select.c libev/ev_kqueue.c libev/ev_poll.c libev/ev_linuxaio.c "
                . "libev/ev_vars.h libev/ev_wrap.h",
     },
     INC       => "-Ilibev",
@@ -283,13 +422,14 @@
        @anyevent,
        "common::sense" => 0,
     },
+    CONFIGURE_REQUIRES => { "ExtUtils::MakeMaker" => 6.52, "Canary::Stability" => 0 },
     VERSION_FROM => "EV.pm",
     PM           => {
-    		    'EV.pm'		=> '$(INST_LIBDIR)/EV.pm',
-    		    'EV/EVAPI.h'	=> '$(INST_LIBDIR)/EV/EVAPI.h',
-    		    'EV/MakeMaker.pm'	=> '$(INST_LIBDIR)/EV/MakeMaker.pm',
-    		    'libev/ev.h'	=> '$(INST_LIBDIR)/EV/ev.h',
-    		    'libev/ev.pod'	=> '$(INST_LIBDIR)/EV/libev.pod',
+		    'EV.pm'		=> '$(INST_LIB)/EV.pm',
+		    'EV/EVAPI.h'	=> '$(INST_LIB)/EV/EVAPI.h',
+		    'EV/MakeMaker.pm'	=> '$(INST_LIB)/EV/MakeMaker.pm',
+		    'libev/ev.h'	=> '$(INST_LIB)/EV/ev.h',
+		    'libev/ev.pod'	=> '$(INST_LIB)/EV/libev.pod',
                  },
     MAN3PODS => {
                     'EV.pm'           => '$(INST_MAN3DIR)/EV.$(MAN3EXT)',
@@ -298,4 +438,3 @@
                 },
 );
 
-