mysql: AFUNIXDatabaseSocketFactoryCJ: Respect timeouts

AFUNIXDatabaseSocketFactoryCJ.connect takes a "loginTimeout" parameter,
and the system properties may specify a "connectTimeout".

While connecting to AF_UNIX sockets appears to not block in the regular
case, let's assume there's a corner case where respecting these values
makes sense.

Follow standard Mysql connector behavior and use these two timeouts to
determine the connect timeout for our unix domain sockets.

#154

junixsocket-mysql/src/main/java/org/newsclub/net/mysql/AFUNIXDatabaseSocketFactoryCJ.java

@@ -25,6 +25,7 @@
 import org.newsclub.net.unix.AFUNIXSocketAddress;
 
 import com.kohlschutter.annotations.compiletime.SuppressFBWarnings;
+import com.mysql.cj.conf.PropertyKey;
 import com.mysql.cj.conf.PropertySet;
 import com.mysql.cj.conf.RuntimeProperty;
 import com.mysql.cj.protocol.ExportControlled;
@@ -61,8 +62,14 @@ public Socket connect(String hostname, int portNumber,
     }
     final File socketFile = new File(sock);
 
-    this.rawSocket = AFUNIXSocket.connectTo(AFUNIXSocketAddress.of(socketFile));
-    return rawSocket;
+    AFUNIXSocket socket = AFUNIXSocket.newInstance();
+
+    int connectTimeout = props.getIntegerProperty(PropertyKey.connectTimeout).getValue();
+    int timeout = MysqlHelper.shorterTimeout(connectTimeout, loginTimeout);
+
+    socket.connect(AFUNIXSocketAddress.of(socketFile), timeout);
+
+    return (this.rawSocket = socket);
   }
 
   @SuppressWarnings({"unchecked"})

junixsocket-mysql/src/main/java/org/newsclub/net/mysql/MysqlHelper.java

@@ -0,0 +1,43 @@
+/*
+ * junixsocket
+ *
+ * Copyright 2009-2023 Christian Kohlschütter
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.newsclub.net.mysql;
+
+/**
+ * Code sharable between code in junixsocket-mysql.
+ *
+ * @author Christian Kohlschütter
+ */
+final class MysqlHelper {
+  private MysqlHelper() {
+  }
+
+  /**
+   * Returns the shorter timeout of two given timeouts (assuming 0 means "unlimited").
+   *
+   * @param a The first timeout.
+   * @param b The second timeout.
+   * @return The shorter timeout.
+   */
+  static int shorterTimeout(int a, int b) {
+    if (a == 0 || (b != 0 && b < a)) {
+      return b;
+    } else {
+      return a;
+    }
+  }
+}

junixsocket-mysql/src/test/java/org/newsclub/net/mysql/AFUNIXDatabaseSocketFactoryCJTest.java

@@ -0,0 +1,51 @@
+/*
+ * junixsocket
+ *
+ * Copyright 2009-2023 Christian Kohlschütter
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.newsclub.net.mysql;
+
+import static org.junit.jupiter.api.Assertions.assertTimeoutPreemptively;
+
+import java.time.Duration;
+
+import org.junit.jupiter.api.Test;
+import org.newsclub.net.unix.AFUNIXServerSocket;
+import org.newsclub.net.unix.AFUNIXSocketAddress;
+
+import com.mysql.cj.conf.DefaultPropertySet;
+import com.mysql.cj.conf.StringPropertyDefinition;
+
+public class AFUNIXDatabaseSocketFactoryCJTest {
+
+  @Test
+  public void testConnectTimeout() throws Exception {
+    AFUNIXSocketAddress addr = AFUNIXSocketAddress.ofNewTempFile();
+    try (AFUNIXServerSocket serverSocket = AFUNIXServerSocket.newInstance()) {
+      serverSocket.bind(addr, 1);
+
+      AFUNIXDatabaseSocketFactoryCJ sf = new AFUNIXDatabaseSocketFactoryCJ();
+
+      DefaultPropertySet props = new DefaultPropertySet();
+      props.addProperty(new StringPropertyDefinition("junixsocket.file", "junixsocket.file", addr
+          .getFile().toString(), true, "description", "0", "category", 1).createRuntimeProperty());
+
+      assertTimeoutPreemptively(Duration.ofSeconds(5), () -> {
+        sf.connect("localhost", 0, props, 1);
+      });
+    }
+  }
+
+}