fix receiveFrom getting into endless loop when stream_select returns early but fread does not produce data and $lastAccess getting reset and moving timeout always into future (#73)

Author: aldas

src/Network/StreamHandler.php

@@ -64,6 +64,9 @@ protected function receiveFrom(array $readStreams, float $timeout = null, $logge
                 $streamIndex = $streamMap[$streamId] ?? null;
                 if ($streamIndex !== null) {
                     $data = fread($stream, 256); // read max 256 bytes
+                    if ($data === false) {
+                        throw new IOException('fread error during receiveFrom');
+                    }
                     if (!empty($data)) {
                         if ($logger) {
                             $logger->debug("Stream {$streamId} @ index: {$streamIndex} received data: ", unpack('H*', $data));
@@ -89,8 +92,10 @@ protected function receiveFrom(array $readStreams, float $timeout = null, $logge
                 if ($timeSpentWaiting >= $timeout) {
                     throw new IOException('Read total timeout expired');
                 }
+            } else {
+                $lastAccess = microtime(true);
             }
-            $lastAccess = microtime(true);
+
         }
         return $result;
     }

tests/unit/Network/StreamHandlerTest.php

@@ -4,6 +4,9 @@
 
 class MockData
 {
+    // $loopForever makes mock return always same data from stream/fread. microtime returns still current time
+    public static $loopForever = false;
+
     public static $fread = null;
     public static $freadCounter = 0;
 
@@ -27,6 +30,10 @@ function fread($handle, $length)
         return \fread($handle, $length);
     }
 
+    if (MockData::$loopForever === true) {
+        return MockData::$fread[0];
+    }
+
     return MockData::$fread[MockData::$freadCounter++];
 }
 
@@ -40,6 +47,10 @@ function microtime($get_as_float = null)
         return \microtime($get_as_float);
     }
 
+    if (MockData::$loopForever === true) {
+        return \microtime($get_as_float);
+    }
+
     return MockData::$microtime[MockData::$microtimeCounter++];
 }
 
@@ -53,6 +64,10 @@ function stream_select(array &$read, array &$write, array &$except, $tv_sec, $tv
         return \stream_select($read, $write, $except, $tv_sec, $tv_usec);
     }
 
+    if (MockData::$loopForever === true) {
+        return MockData::$stream_select[0];
+    }
+
     return MockData::$stream_select[MockData::$stream_selectCounter++];
 }
 
@@ -69,6 +84,7 @@ class StreamHandlerTest extends TestCase
 {
     protected function tearDown(): void
     {
+        MockData::$loopForever = false;
         MockData::$freadCounter = 0;
         MockData::$microtimeCounter = 0;
         MockData::$stream_selectCounter = 0;
@@ -102,6 +118,33 @@ public function testReturnData()
 
     }
 
+    public function testSelectReturnButFreadFailure()
+    {
+        $this->expectExceptionMessage("fread error during receiveFrom");
+        $this->expectException(IOException::class);
+
+        // full packet is received with 2 fread calls (tcp packet fragmentation example)
+        $returnedPacketPart1 = "\xda\x87\x00\x00\x00\x03\x00\x81";
+        $returnedPacketPart2 = "\x03";
+        $expected = $returnedPacketPart1 . $returnedPacketPart2;
+
+        MockData::$loopForever = true;
+        MockData::$fread = [false]; // fread() returns false - something is wrong with stream/socket
+        MockData::$stream_select = ['x'];
+
+        $handler = new ForTestStreamHandler();
+
+        $readStreams = ['stream'];
+        $timeout = null;
+        $logger = new MockLogger();
+
+        $result = $handler->receiveFrom($readStreams, $timeout, $logger);
+
+        $this->assertEquals([$expected], $result);
+        $this->assertEquals(2, MockData::$freadCounter);
+
+    }
+
     public function testExceptionFromStreamSelect()
     {
         $this->expectExceptionMessage("stream_select interrupted by an incoming signal");