core: Move ConfigOrError up level up. (#5578)

This class is used in other places than just NameResolver.Helper.  It
should not be an inner class of Helper.

Strictly speaking this is an API-breaking change.  However, this is
part of the service config error handling API that hasn't been done
yet.  Nobody has a legitimate reason to use it.

core/src/main/java/io/grpc/LoadBalancerProvider.java

@@ -17,7 +17,7 @@
 package io.grpc;
 
 import com.google.common.base.MoreObjects;
-import io.grpc.NameResolver.Helper.ConfigOrError;
+import io.grpc.NameResolver.ConfigOrError;
 import java.util.Map;
 
 /**

core/src/main/java/io/grpc/NameResolver.java

@@ -21,7 +21,6 @@ import static com.google.common.base.Preconditions.checkNotNull;
 
 import com.google.common.base.MoreObjects;
 import com.google.common.base.Objects;
-import io.grpc.NameResolver.Helper.ConfigOrError;
 import java.lang.annotation.Documented;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -355,93 +354,6 @@ public abstract class NameResolver {
     public ConfigOrError parseServiceConfig(Map<String, ?> rawServiceConfig) {
       throw new UnsupportedOperationException("should have been implemented");
     }
-
-    /**
-     * Represents either a successfully parsed service config, containing all necessary parts to be
-     * later applied by the channel, or a Status containing the error encountered while parsing.
-     *
-     * @since 1.20.0
-     */
-    public static final class ConfigOrError {
-
-      private static final class UnknownConfig {
-
-        UnknownConfig() {}
-
-        @Override
-        public String toString() {
-          return "service config is unused";
-        }
-      }
-
-      /**
-       * A sentinel value indicating that service config is not supported.   This can be used to
-       * indicate that parsing of the service config is neither right nor wrong, but doesn't have
-       * any meaning.
-       */
-      public static final ConfigOrError UNKNOWN_CONFIG =
-          ConfigOrError.fromConfig(new UnknownConfig());
-
-      /**
-       * Returns a {@link ConfigOrError} for the successfully parsed config.
-       */
-      public static ConfigOrError fromConfig(Object config) {
-        return new ConfigOrError(config);
-      }
-
-      /**
-       * Returns a {@link ConfigOrError} for the failure to parse the config.
-       *
-       * @param status a non-OK status
-       */
-      public static ConfigOrError fromError(Status status) {
-        return new ConfigOrError(status);
-      }
-
-      private final Status status;
-      private final Object config;
-
-      private ConfigOrError(Object config) {
-        this.config = checkNotNull(config, "config");
-        this.status = null;
-      }
-
-      private ConfigOrError(Status status) {
-        this.config = null;
-        this.status = checkNotNull(status, "status");
-        checkArgument(!status.isOk(), "cannot use OK status: %s", status);
-      }
-
-      /**
-       * Returns config if exists, otherwise null.
-       */
-      @Nullable
-      public Object getConfig() {
-        return config;
-      }
-
-      /**
-       * Returns error status if exists, otherwise null.
-       */
-      @Nullable
-      public Status getError() {
-        return status;
-      }
-
-      @Override
-      public String toString() {
-        if (config != null) {
-          return MoreObjects.toStringHelper(this)
-              .add("config", config)
-              .toString();
-        } else {
-          assert status != null;
-          return MoreObjects.toStringHelper(this)
-              .add("error", status)
-              .toString();
-        }
-      }
-    }
   }
 
   /**
@@ -598,4 +510,90 @@ public abstract class NameResolver {
       }
     }
   }
+  
+  /**
+   * Gets the attributes associated with the servers resolved by name resolution.  If there are
+   * no attributes, {@link Attributes#EMPTY} will be returned.
+   *
+   * @since 1.21.0
+   */
+  public static final class ConfigOrError {
+    private static final class UnknownConfig {
+
+      UnknownConfig() {}
+
+      @Override
+      public String toString() {
+        return "service config is unused";
+      }
+    }
+
+    /**
+     * A sentinel value indicating that service config is not supported.   This can be used to
+     * indicate that parsing of the service config is neither right nor wrong, but doesn't have
+     * any meaning.
+     */
+    public static final ConfigOrError UNKNOWN_CONFIG =
+        ConfigOrError.fromConfig(new UnknownConfig());
+
+    /**
+     * Returns a {@link ConfigOrError} for the successfully parsed config.
+     */
+    public static ConfigOrError fromConfig(Object config) {
+      return new ConfigOrError(config);
+    }
+
+    /**
+     * Returns a {@link ConfigOrError} for the failure to parse the config.
+     *
+     * @param status a non-OK status
+     */
+    public static ConfigOrError fromError(Status status) {
+      return new ConfigOrError(status);
+    }
+
+    private final Status status;
+    private final Object config;
+
+    private ConfigOrError(Object config) {
+      this.config = checkNotNull(config, "config");
+      this.status = null;
+    }
+
+    private ConfigOrError(Status status) {
+      this.config = null;
+      this.status = checkNotNull(status, "status");
+      checkArgument(!status.isOk(), "cannot use OK status: %s", status);
+    }
+
+    /**
+     * Returns config if exists, otherwise null.
+     */
+    @Nullable
+    public Object getConfig() {
+      return config;
+    }
+
+    /**
+     * Returns error status if exists, otherwise null.
+     */
+    @Nullable
+    public Status getError() {
+      return status;
+    }
+
+    @Override
+    public String toString() {
+      if (config != null) {
+        return MoreObjects.toStringHelper(this)
+            .add("config", config)
+            .toString();
+      } else {
+        assert status != null;
+        return MoreObjects.toStringHelper(this)
+            .add("error", status)
+            .toString();
+      }
+    }
+  }
 }

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

@@ -31,7 +31,7 @@ import io.grpc.LoadBalancer.PickSubchannelArgs;
 import io.grpc.LoadBalancer.SubchannelPicker;
 import io.grpc.LoadBalancerProvider;
 import io.grpc.LoadBalancerRegistry;
-import io.grpc.NameResolver.Helper.ConfigOrError;
+import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.Status;
 import io.grpc.internal.ServiceConfigUtil.LbConfig;
 import java.util.ArrayList;

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

@@ -28,7 +28,7 @@ import com.google.common.base.VerifyException;
 import io.grpc.Attributes;
 import io.grpc.EquivalentAddressGroup;
 import io.grpc.NameResolver;
-import io.grpc.NameResolver.Helper.ConfigOrError;
+import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.ProxiedSocketAddress;
 import io.grpc.ProxyDetector;
 import io.grpc.Status;

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

@@ -61,6 +61,7 @@ import io.grpc.ManagedChannel;
 import io.grpc.Metadata;
 import io.grpc.MethodDescriptor;
 import io.grpc.NameResolver;
+import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.NameResolver.ResolutionResult;
 import io.grpc.ProxyDetector;
 import io.grpc.Status;

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

@@ -18,7 +18,7 @@ package io.grpc.internal;
 
 import io.grpc.LoadBalancer;
 import io.grpc.LoadBalancerProvider;
-import io.grpc.NameResolver.Helper.ConfigOrError;
+import io.grpc.NameResolver.ConfigOrError;
 import java.util.Map;
 
 /**

core/src/main/java/io/grpc/util/SecretRoundRobinLoadBalancerProvider.java

@@ -18,7 +18,7 @@ package io.grpc.util;
 
 import io.grpc.LoadBalancer;
 import io.grpc.LoadBalancerProvider;
-import io.grpc.NameResolver.Helper.ConfigOrError;
+import io.grpc.NameResolver.ConfigOrError;
 import java.util.Map;
 
 /**

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

@@ -39,7 +39,7 @@ import com.google.common.testing.FakeTicker;
 import io.grpc.EquivalentAddressGroup;
 import io.grpc.HttpConnectProxiedSocketAddress;
 import io.grpc.NameResolver;
-import io.grpc.NameResolver.Helper.ConfigOrError;
+import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.NameResolver.ResolutionResult;
 import io.grpc.ProxyDetector;
 import io.grpc.Status;

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

@@ -91,7 +91,7 @@ import io.grpc.Metadata;
 import io.grpc.MethodDescriptor;
 import io.grpc.MethodDescriptor.MethodType;
 import io.grpc.NameResolver;
-import io.grpc.NameResolver.Helper.ConfigOrError;
+import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.NameResolver.ResolutionResult;
 import io.grpc.ProxiedSocketAddress;
 import io.grpc.ProxyDetector;

grpclb/src/main/java/io/grpc/grpclb/GrpclbLoadBalancerProvider.java

@@ -20,7 +20,7 @@ import com.google.common.base.Stopwatch;
 import io.grpc.Internal;
 import io.grpc.LoadBalancer;
 import io.grpc.LoadBalancerProvider;
-import io.grpc.NameResolver.Helper.ConfigOrError;
+import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.Status;
 import io.grpc.grpclb.GrpclbState.Mode;
 import io.grpc.internal.ExponentialBackoffPolicy;

services/src/main/java/io/grpc/services/internal/HealthCheckingRoundRobinLoadBalancerProvider.java

@@ -22,7 +22,7 @@ import io.grpc.Internal;
 import io.grpc.LoadBalancer;
 import io.grpc.LoadBalancer.Helper;
 import io.grpc.LoadBalancerProvider;
-import io.grpc.NameResolver.Helper.ConfigOrError;
+import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.services.HealthCheckingLoadBalancerUtil;
 import java.util.Map;
 

xds/src/main/java/io/grpc/xds/XdsLoadBalancer.java

@@ -30,7 +30,7 @@ import io.grpc.ConnectivityStateInfo;
 import io.grpc.EquivalentAddressGroup;
 import io.grpc.LoadBalancer;
 import io.grpc.LoadBalancerRegistry;
-import io.grpc.NameResolver.Helper.ConfigOrError;
+import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.Status;
 import io.grpc.SynchronizationContext.ScheduledHandle;
 import io.grpc.internal.ServiceConfigUtil.LbConfig;

xds/src/main/java/io/grpc/xds/XdsLoadBalancerProvider.java

@@ -23,7 +23,7 @@ import io.grpc.LoadBalancer;
 import io.grpc.LoadBalancer.Helper;
 import io.grpc.LoadBalancerProvider;
 import io.grpc.LoadBalancerRegistry;
-import io.grpc.NameResolver.Helper.ConfigOrError;
+import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.Status;
 import io.grpc.internal.ServiceConfigUtil;
 import io.grpc.internal.ServiceConfigUtil.LbConfig;