libevent: Add libevent main loop adapter

Glue for dispatching via libevent.  Requires 2.0.21 or later.

Signed-off-by: Philip Prindeville <philipp@redfish-solutions.com>

.travis.yml

@@ -10,3 +10,4 @@ before_install:
   - sudo apt-get install python-gi-dev gir1.2-gtk-3.0
   - sudo apt-get install mono-mcs qtbase5-dev
   - sudo apt-get install intltool
+  - sudo apt-get install libevent-dev

Makefile.am

@@ -40,6 +40,7 @@ EXTRA_DIST = \
 	avahi-core.pc.in \
 	avahi-client.pc.in \
 	avahi-glib.pc.in \
+	avahi-libevent.pc.in \
 	avahi-gobject.pc.in \
 	avahi-qt3.pc.in \
 	avahi-qt4.pc.in \
@@ -77,6 +78,7 @@ SUBDIRS = \
 	avahi-autoipd \
 	avahi-ui \
 	avahi-ui-sharp \
+	avahi-libevent \
 	po
 
 DX_INPUT = \
@@ -155,6 +157,11 @@ DX_INPUT += \
 	$(srcdir)/avahi-ui/avahi-ui.h
 endif
 
+if HAVE_LIBEVENT
+DX_INPUT += \
+	$(srcdir)/avahi-libevent/libevent-watch.h
+endif
+
 pkgconfigdir = $(libdir)/pkgconfig
 
 %.pc: %.pc.in
@@ -226,6 +233,11 @@ pkgconfig_DATA += avahi-qt5.pc
 CLEANFILES += avahi-qt5.pc
 endif
 
+if HAVE_LIBEVENT
+pkgconfig_DATA += avahi-libevent.pc
+CLEANFILES += avahi-libevent.pc
+endif
+
 CLEANFILES += avahi.devhelp
 
 avahi.devhelp: doxygen-run

avahi-libevent.pc.in

@@ -0,0 +1,11 @@
+prefix=@prefix@
+exec_prefix=${prefix}
+libdir=@libdir@
+includedir=${prefix}/include
+
+Name: avahi-libevent
+Description: Avahi Multicast DNS Responder (libevent Support)
+Version: @PACKAGE_VERSION@
+Requires: libevent-2.1.5
+Libs: -L${libdir} -lavahi-libevent
+Cflags: -D_REENTRANT -I${includedir}

avahi-libevent/.gitignore

@@ -0,0 +1,8 @@
+*.o
+*.lo
+*.la
+Makefile
+Makefile.in
+.deps
+.libs
+libevent-watch-test

avahi-libevent/Makefile.am

@@ -0,0 +1,51 @@
+# This file is part of avahi.
+#
+# avahi is free software; you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation; either version 2 of the
+# License, or (at your option) any later version.
+#
+# avahi is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
+# License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with avahi; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+# USA.
+
+AM_CFLAGS=-I$(top_srcdir)
+
+# This cool debug trap works on i386/gcc only
+AM_CFLAGS+='-DDEBUG_TRAP=__asm__("int $$3")'
+
+if HAVE_LIBEVENT
+
+avahilibeventincludedir=$(includedir)/avahi-libevent
+
+avahilibeventinclude_HEADERS = \
+	libevent-watch.h
+
+lib_LTLIBRARIES = \
+	libavahi-libevent.la
+
+if ENABLE_TESTS
+noinst_PROGRAMS = \
+	libevent-watch-test
+endif
+
+libavahi_libevent_la_SOURCES = \
+	libevent-watch.c libevent-watch.h
+
+libavahi_libevent_la_CFLAGS = $(AM_CFLAGS) $(LIBEVENT_CFLAGS)
+libavahi_libevent_la_LIBADD = $(AM_LDADD) ../avahi-common/libavahi-common.la $(LIBEVENT_LIBS)
+libavahi_libevent_la_LDFLAGS = $(AM_LDFLAGS)  -version-info $(LIBAVAHI_LIBEVENT_VERSION_INFO)
+
+libevent_watch_test_SOURCES = \
+	libevent-watch.c libevent-watch.h \
+	libevent-watch-test.c
+libevent_watch_test_CFLAGS = $(AM_CFLAGS) $(LIBEVENT_CFLAGS)
+libevent_watch_test_LDADD = $(AM_LDADD) ../avahi-common/libavahi-common.la $(LIBEVENT_LIBS)
+
+endif

avahi-libevent/libevent-watch-test.c

@@ -0,0 +1,96 @@
+/***
+  This file is part of avahi.
+
+  avahi is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+
+  avahi is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
+  Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with avahi; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+
+#include <event2/event.h>
+
+#include <avahi-common/watch.h>
+#include <avahi-common/timeval.h>
+#include <avahi-common/gccmacro.h>
+
+#include "libevent-watch.h"
+
+static const AvahiPoll *api = NULL;
+static struct event_base *base = NULL;
+
+static void callback(AvahiWatch *w, int fd, AvahiWatchEvent event, AVAHI_GCC_UNUSED void *userdata)
+{
+    if (event & AVAHI_WATCH_IN) {
+        ssize_t r;
+        char c;
+
+        if ((r = read(fd, &c, 1)) <= 0) {
+            fprintf(stderr, "read() failed: %s\n", r < 0 ? strerror(errno) : "EOF");
+            api->watch_free(w);
+            return;
+        }
+
+        printf("Read: %c\n", c >= 32 && c < 127 ? c : '.');
+    }
+}
+
+static void wakeup(AvahiTimeout *t, AVAHI_GCC_UNUSED void *userdata)
+{
+    struct timeval tv;
+    static unsigned i = 0;
+
+    printf("Wakeup #%u\n", i++);
+
+    if (i > 10)
+	event_base_loopbreak(base);
+
+    avahi_elapse_time(&tv, 1000, 0);
+    api->timeout_update(t, &tv);
+}
+
+int main(AVAHI_GCC_UNUSED int argc, AVAHI_GCC_UNUSED char *argv[])
+{
+    AvahiLibeventPoll *ep;
+    struct timeval tv;
+
+    base = event_base_new();
+    assert(base);
+
+    ep = avahi_libevent_poll_new(base);
+    assert(ep);
+
+    api = avahi_libevent_poll_get(ep);
+
+    api->watch_new(api, 0, AVAHI_WATCH_IN, callback, NULL);
+
+    avahi_elapse_time(&tv, 1000, 0);
+    api->timeout_new(api, &tv, wakeup, NULL);
+
+    event_base_dispatch(base);
+
+    avahi_libevent_poll_free(ep);
+
+    event_base_free(base);
+
+    return 0;
+}