core: Add RFC 3986 support for 'dns' target URIs

# Conflicts:
#	core/src/test/java/io/grpc/internal/DnsNameResolverProviderTest.java

Author: jdcormie

core/src/main/java/io/grpc/internal/DnsNameResolverProvider.java

@@ -20,12 +20,15 @@
 import com.google.common.base.Stopwatch;
 import io.grpc.InternalServiceProviders;
 import io.grpc.NameResolver;
+import io.grpc.NameResolver.Args;
 import io.grpc.NameResolverProvider;
+import io.grpc.Uri;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import java.net.URI;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.List;
 
 /**
  * A provider for {@link DnsNameResolver}.
@@ -54,6 +57,7 @@ public final class DnsNameResolverProvider extends NameResolverProvider {
 
   @Override
   public NameResolver newNameResolver(URI targetUri, NameResolver.Args args) {
+    // TODO(jdcormie): Remove once RFC 3986 migration is complete.
     if (SCHEME.equals(targetUri.getScheme())) {
       String targetPath = Preconditions.checkNotNull(targetUri.getPath(), "targetPath");
       Preconditions.checkArgument(targetPath.startsWith("/"),
@@ -71,6 +75,25 @@ public NameResolver newNameResolver(URI targetUri, NameResolver.Args args) {
     }
   }
 
+  @Override
+  public NameResolver newNameResolver(Uri targetUri, final Args args) {
+    if (SCHEME.equals(targetUri.getScheme())) {
+      List<String> pathSegments = targetUri.getPathSegments();
+      Preconditions.checkArgument(!pathSegments.isEmpty(),
+          "expected 1 path segment in target %s but found %s", targetUri, pathSegments);
+      String domainNameToResolve = pathSegments.get(0);
+      return new DnsNameResolver(
+          targetUri.getAuthority(),
+          domainNameToResolve,
+          args,
+          GrpcUtil.SHARED_CHANNEL_EXECUTOR,
+          Stopwatch.createUnstarted(),
+          IS_ANDROID);
+    } else {
+      return null;
+    }
+  }
+
   @Override
   public String getDefaultScheme() {
     return SCHEME;

core/src/test/java/io/grpc/internal/DnsNameResolverProviderTest.java

@@ -17,23 +17,35 @@
 package io.grpc.internal;
 
 import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.TruthJUnit.assume;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.mock;
 
 import io.grpc.ChannelLogger;
 import io.grpc.NameResolver;
 import io.grpc.NameResolver.ServiceConfigParser;
 import io.grpc.SynchronizationContext;
+import io.grpc.Uri;
 import java.net.URI;
+import java.util.Arrays;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
 
 /** Unit tests for {@link DnsNameResolverProvider}. */
-@RunWith(JUnit4.class)
+@RunWith(Parameterized.class)
 public class DnsNameResolverProviderTest {
   private final FakeClock fakeClock = new FakeClock();
 
+  @Parameters(name = "enableRfc3986UrisParam={0}")
+  public static Iterable<Object[]> data() {
+    return Arrays.asList(new Object[][] {{true}, {false}});
+  }
+
+  @Parameter public boolean enableRfc3986UrisParam;
+
   private final SynchronizationContext syncContext = new SynchronizationContext(
       new Thread.UncaughtExceptionHandler() {
         @Override
@@ -59,34 +71,47 @@ public void isAvailable() {
 
   @Test
   public void newNameResolver_acceptsHostAndPort() {
-    NameResolver nameResolver = provider.newNameResolver(URI.create("dns:///localhost:443"), args);
+    DnsNameResolver nameResolver = newNameResolver("dns:///localhost:443", args);
+    assertThat(nameResolver).isNotNull();
+    assertThat(nameResolver.getClass()).isSameInstanceAs(DnsNameResolver.class);
+    assertThat(nameResolver.getServiceAuthority()).isEqualTo("localhost:443");
+  }
+
+  @Test
+  public void newNameResolver_acceptsRootless() {
+    assume().that(enableRfc3986UrisParam).isTrue();
+    DnsNameResolver nameResolver = newNameResolver("dns:localhost:443", args);
     assertThat(nameResolver).isNotNull();
     assertThat(nameResolver.getClass()).isSameInstanceAs(DnsNameResolver.class);
     assertThat(nameResolver.getServiceAuthority()).isEqualTo("localhost:443");
   }
 
   @Test
   public void newNameResolver_rejectsNonDnsScheme() {
-    NameResolver nameResolver =
-        provider.newNameResolver(URI.create("notdns:///localhost:443"), args);
+    DnsNameResolver nameResolver = newNameResolver("notdns:///localhost:443", args);
     assertThat(nameResolver).isNull();
   }
 
   @Test
   public void newNameResolver_toleratesTrailingPathSegments() {
-    NameResolver nameResolver =
-        provider.newNameResolver(URI.create("dns:///foo.googleapis.com/ig/nor/ed"), args);
+    DnsNameResolver nameResolver = newNameResolver("dns:///foo.googleapis.com/ig/nor/ed", args);
     assertThat(nameResolver).isNotNull();
     assertThat(nameResolver.getClass()).isSameInstanceAs(DnsNameResolver.class);
     assertThat(nameResolver.getServiceAuthority()).isEqualTo("foo.googleapis.com");
   }
 
   @Test
   public void newNameResolver_toleratesAuthority() {
-    NameResolver nameResolver =
-        provider.newNameResolver(URI.create("dns://8.8.8.8/foo.googleapis.com"), args);
+    DnsNameResolver nameResolver = newNameResolver("dns://8.8.8.8/foo.googleapis.com", args);
     assertThat(nameResolver).isNotNull();
     assertThat(nameResolver.getClass()).isSameInstanceAs(DnsNameResolver.class);
     assertThat(nameResolver.getServiceAuthority()).isEqualTo("foo.googleapis.com");
   }
+
+  private DnsNameResolver newNameResolver(String uriString, NameResolver.Args args) {
+    return (DnsNameResolver)
+        (enableRfc3986UrisParam
+            ? provider.newNameResolver(Uri.create(uriString), args)
+            : provider.newNameResolver(URI.create(uriString), args));
+  }
 }