Fix net.i2p.util.Addresses::getIP empty string

The standard library behavior is to return the localhost when null or an empty string is passed.
getIP seeked to override that behavior, but didn't treat the empty string case.

core/java/src/net/i2p/util/Addresses.java

@@ -122,10 +122,9 @@ public abstract class Addresses {
      *
      *  Warning, very slow on Windows, appx. 200ms + 50ms/interface
      *
-     *  @return a sorted set of all addresses including wildcard
      *  @param includeLocal whether to include local
      *  @param includeIPv6 whether to include IPV6
-     *  @return a Set of all addresses
+     *  @return a sorted set of all addresses including wildcard
      *  @since 0.8.3
      */
     public static SortedSet<String> getAddresses(boolean includeLocal, boolean includeIPv6) {
@@ -141,11 +140,10 @@ public abstract class Addresses {
      *
      *  Warning, very slow on Windows, appx. 200ms + 50ms/interface
      *
-     *  @return a sorted set of all addresses
      *  @param includeSiteLocal whether to include private like 192.168.x.x
      *  @param includeLoopbackAndWildcard whether to include 127.x.x.x and 0.0.0.0
      *  @param includeIPv6 whether to include IPV6
-     *  @return a Set of all addresses
+     *  @return a sorted set of all addresses
      *  @since 0.9.4
      */
     public static SortedSet<String> getAddresses(boolean includeSiteLocal,
@@ -163,12 +161,11 @@ public abstract class Addresses {
      *
      *  Warning, very slow on Windows, appx. 200ms + 50ms/interface
      *
-     *  @return a sorted set of all addresses
      *  @param includeSiteLocal whether to include private like 192.168.x.x
      *  @param includeLoopbackAndWildcard whether to include 127.x.x.x and 0.0.0.0
      *  @param includeIPv6 whether to include IPV6
      *  @param includeIPv6Temporary whether to include IPV6 temporary addresses
-     *  @return a Set of all addresses
+     *  @return a sorted set of all addresses
      *  @since 0.9.46
      */
     public static SortedSet<String> getAddresses(boolean includeSiteLocal,
@@ -402,7 +399,7 @@ public abstract class Addresses {
      *  @since 0.9.3
      */
     public static byte[] getIP(String host) {
-        if (host == null)
+        if (host == null || host.isEmpty())
             return null;
         byte[] rv;
         synchronized (_IPAddress) {

core/java/test/junit/net/i2p/util/AddressesTest.java

@@ -0,0 +1,145 @@
+package net.i2p.util;
+
+import org.junit.Test;
+
+import java.net.Inet6Address;
+import java.net.UnknownHostException;
+
+import static org.junit.Assert.*;
+
+/**
+ * @since 0.9.49
+ */
+public class AddressesTest {
+
+    @Test
+    public void getIPNull() {
+        assertNull(Addresses.getIP(null));
+    }
+
+    @Test
+    public void getIPEmptyString() {
+        assertNull(Addresses.getIP(""));
+    }
+
+    @Test
+    public void getIPWithIPString() {
+        byte[] address = {
+            1, 2, 3, 4
+        };
+        assertArrayEquals(address, Addresses.getIP("1.2.3.4"));
+    }
+
+    @Test
+    public void getPort() {
+        assertEquals(80, Addresses.getPort("80"));
+    }
+
+    @Test
+    public void getPort__invalidPort() {
+        String[] strings = {
+            "",
+            " 80",
+            "-100",
+            "a",
+            "99999",
+            null
+        };
+        for (String string : strings) {
+            assertEquals(0, Addresses.getPort(string));
+        }
+    }
+
+    @Test
+    public void isIPAddress() {
+        assertTrue(Addresses.isIPAddress("127.0.0.1"));
+        assertTrue(Addresses.isIPAddress("::1"));
+    }
+
+    @Test
+    public void isIPv6Address() {
+        assertTrue(Addresses.isIPv6Address("::1"));
+        assertFalse(Addresses.isIPv6Address(""));
+    }
+
+    @Test
+    public void isIPv4Address() {
+        assertTrue(Addresses.isIPv4Address("127.0.0.1"));
+        assertFalse(Addresses.isIPv4Address(""));
+    }
+
+    /**
+     * Should always return false when the address isn't in the cache
+     */
+    @Test
+    public void isDynamic() throws UnknownHostException {
+        String host = "localhost";
+        byte[] address = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
+        assertFalse(Addresses.isDynamic((Inet6Address) Inet6Address.getByAddress(host, address)));
+    }
+
+    /**
+     * Should always return false when the address isn't in the cache
+     */
+    @Test
+    public void isDeprecated() throws UnknownHostException {
+        String host = "localhost";
+        byte[] address = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
+        assertFalse(Addresses.isDeprecated((Inet6Address) Inet6Address.getByAddress(host, address)));
+    }
+
+    @Test
+    public void testToString() {
+        byte[] address = {127, 0, 0, 1};
+        assertEquals("127.0.0.1", Addresses.toString(address));
+    }
+
+    @Test
+    public void testToString__ipv4withPort() {
+        byte[] address = {127, 0, 0, 1};
+        assertEquals("127.0.0.1:80", Addresses.toString(address, 80));
+    }
+
+    @Test
+    public void testToString__ipv6withPort() {
+        byte[] address = {
+            0, 0, 0, 0,
+            0, 0, 0, 0,
+            0, 0, 0, 0,
+            0, 0, 0, 1,
+        };
+        assertEquals("[0:0:0:0:0:0:0:1]:80", Addresses.toString(address, 80));
+    }
+
+    @Test
+    public void testToString__null() {
+        assertEquals("null", Addresses.toString(null));
+    }
+
+    @Test
+    public void testToString__nullWithPort() {
+        assertEquals("null:80", Addresses.toString(null, 80));
+    }
+
+    @Test
+    public void testToString__badLength() {
+        byte[] address = {1};
+        assertTrue(Addresses.toString(address).startsWith("bad IP length"));
+    }
+
+    @Test
+    public void testToString__badLengthWithPort() {
+        byte[] address = {1};
+        String string = Addresses.toString(address, 80);
+        String expectedStartString = "(bad IP length";
+        assertTrue(
+            String.format("%s doesn't start with: %s", string, expectedStartString),
+            string.startsWith(expectedStartString)
+        );
+        String expectedEndString = "80";
+        assertTrue(
+            String.format("%s doesn't end with: %s", string, expectedEndString),
+            string.endsWith(expectedEndString)
+        );
+    }
+}