Reworked signal handling to keep the loop running as long as there are any signal handlers registered to the loop

WyriHaximus · WyriHaximus · commit 65c0a9b027dc · 2017-10-30T16:07:24.000+01:00
diff --git a/examples/04-signals.php b/examples/04-signals.php
@@ -10,9 +10,4 @@
     $loop->stop();
 });
 
-// This timer is here to keep the loop alive, signaling by itself doesn't do that
-$loop->addPeriodicTimer(1, function () {
-    echo 'Timer tick', PHP_EOL;
-});
-
 $loop->run();
diff --git a/src/ExtEventLoop.php b/src/ExtEventLoop.php
@@ -35,6 +35,7 @@ public function __construct(EventBaseConfig $config = null)
         $this->timerEvents = new SplObjectStorage();
 
         $this->signals = new SignalsHandler(
+            $this,
             function ($signal) {
                 $this->signalEvents[$signal] = Event::signal($this->eventBase, $signal, $f = function () use ($signal, &$f) {
                     $this->signals->call($signal);
diff --git a/src/LibEvLoop.php b/src/LibEvLoop.php
@@ -33,6 +33,7 @@ public function __construct()
         $this->timerEvents = new SplObjectStorage();
 
         $this->signals = new SignalsHandler(
+            $this,
             function ($signal) {
                 $this->signalEvents[$signal] = new SignalEvent($f = function () use ($signal, &$f) {
                     $this->signals->call($signal);
diff --git a/src/LibEventLoop.php b/src/LibEventLoop.php
@@ -37,6 +37,7 @@ public function __construct()
         $this->timerEvents = new SplObjectStorage();
 
         $this->signals = new SignalsHandler(
+            $this,
             function ($signal) {
                 $this->signalEvents[$signal] = event_new();
                 event_set($this->signalEvents[$signal], $signal, EV_PERSIST | EV_SIGNAL, $f = function () use ($signal, &$f) {
diff --git a/src/SignalsHandler.php b/src/SignalsHandler.php
@@ -2,17 +2,22 @@
 
 namespace React\EventLoop;
 
+use React\EventLoop\Timer\TimerInterface;
+
 /**
  * @internal
  */
 final class SignalsHandler
 {
+    private $loop;
+    private $timer;
     private $signals = [];
     private $on;
     private $off;
 
-    public function __construct(callable $on, callable $off)
+    public function __construct(LoopInterface $loop, callable $on, callable $off)
     {
+        $this->loop = $loop;
         $this->on = $on;
         $this->off = $off;
     }
@@ -27,6 +32,10 @@ public function __destruct()
 
     public function add($signal, callable $listener)
     {
+        if (count($this->signals) == 0 && $this->timer === null) {
+            $this->timer = $this->loop->addPeriodicTimer(1, function () {});
+        }
+
         if (!isset($this->signals[$signal])) {
             $this->signals[$signal] = [];
 
@@ -56,6 +65,11 @@ public function remove($signal, callable $listener)
             $off = $this->off;
             $off($signal);
         }
+
+        if (count($this->signals) == 0 && $this->timer instanceof TimerInterface) {
+            $this->loop->cancelTimer($this->timer);
+            $this->timer = null;
+        }
     }
 
     public function call($signal)
diff --git a/src/StreamSelectLoop.php b/src/StreamSelectLoop.php
@@ -31,6 +31,7 @@ public function __construct()
         $this->timers = new Timers();
         $this->pcntl = extension_loaded('pcntl');
         $this->signals = new SignalsHandler(
+            $this,
             function ($signal) {
                 \pcntl_signal($signal, $f = function ($signal) use (&$f) {
                     $this->signals->call($signal);
diff --git a/tests/AbstractLoopTest.php b/tests/AbstractLoopTest.php
@@ -453,12 +453,39 @@ public function testSignalMultipleUsagesForTheSameListener()
         $this->assertSame(1, $funcCallCount);
     }
 
-    public function testSignalsDontKeepTheLoopRunning()
+    public function testSignalsKeepTheLoopRunning()
     {
-        $this->loop->addSignal(SIGUSR1, function () {});
-        $this->loop->addTimer(0.1, function () {});
+        $function = function () {};
+        $this->loop->addSignal(SIGUSR1, $function);
+        $this->loop->addTimer(1.5, function () use ($function) {
+            $this->loop->removeSignal(SIGUSR1, $function);
+            $this->loop->stop();
+        });
+
+        $this->assertRunSlowerThan(1.5);
+    }
+
+    public function testSignalsKeepTheLoopRunningAndRemovingItStopsTheLoop()
+    {
+        $function = function () {};
+        $this->loop->addSignal(SIGUSR1, $function);
+        $this->loop->addTimer(1.5, function () use ($function) {
+            $this->loop->removeSignal(SIGUSR1, $function);
+        });
+
+        $this->assertRunFasterThan(1.6);
+    }
+
+    private function assertRunSlowerThan($minInterval)
+    {
+        $start = microtime(true);
+
+        $this->loop->run();
+
+        $end = microtime(true);
+        $interval = $end - $start;
 
-        $this->assertRunFasterThan(0.2);
+        $this->assertLessThan($interval, $minInterval);
     }
 
     private function assertRunFasterThan($maxInterval)
diff --git a/tests/SignalsHandlerTest.php b/tests/SignalsHandlerTest.php
@@ -2,6 +2,7 @@
 
 namespace React\Tests\EventLoop;
 
+use React\EventLoop\Factory;
 use React\EventLoop\SignalsHandler;
 
 final class SignalsHandlerTest extends TestCase
@@ -15,6 +16,7 @@ public function testEmittedEventsAndCallHandling()
             $callCount++;
         };
         $signals = new SignalsHandler(
+            Factory::create(),
             function () use (&$onCount) {
                 $onCount++;
             },
