Rollback of commit 8e7da8704dba78dba47fbaa0eafce3a91c2deb13.

*** Reason for rollback ***

--
MOS_MIGRATED_REVID=109005097

14 files changed, 226 insertions, 460 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/commands/FetchCommand.java b/src/main/java/com/google/devtools/build/lib/bazel/commands/FetchCommand.java
index 6408276f99..c4a5dca0ef 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/commands/FetchCommand.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/commands/FetchCommand.java
@@ -22,7 +22,6 @@ import com.google.devtools.build.lib.events.Event;
 import com.google.devtools.build.lib.packages.Target;
 import com.google.devtools.build.lib.pkgcache.PackageCacheOptions;
 import com.google.devtools.build.lib.query2.AbstractBlazeQueryEnvironment;
-import com.google.devtools.build.lib.query2.engine.Callback;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.Setting;
 import com.google.devtools.build.lib.query2.engine.QueryException;
 import com.google.devtools.build.lib.query2.engine.QueryExpression;
@@ -122,13 +121,7 @@ public final class FetchCommand implements BlazeCommand {
 
     // 2. Evaluate expression:
     try {
-      queryEnv.evaluateQuery(expr, new Callback<Target>() {
-        @Override
-        public void process(Iterable<Target> partialResult)
-            throws QueryException, InterruptedException {
-          // Throw away the result.
-        }
-      });
+      queryEnv.evaluateQuery(expr);
     } catch (QueryException | InterruptedException e) {
       // Keep consistent with reportBuildFileError()
       env.getReporter().handle(Event.error(e.getMessage()));
diff --git a/src/main/java/com/google/devtools/build/lib/query2/AbstractBlazeQueryEnvironment.java b/src/main/java/com/google/devtools/build/lib/query2/AbstractBlazeQueryEnvironment.java
index b3e4341715..11eef89f1d 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/AbstractBlazeQueryEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/AbstractBlazeQueryEnvironment.java
@@ -17,7 +17,6 @@ import com.google.common.base.Preconditions;
 import com.google.common.base.Predicate;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Iterables;
 import com.google.common.collect.Sets;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.cmdline.TargetParsingException;
@@ -32,11 +31,11 @@ import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
 import com.google.devtools.build.lib.pkgcache.TargetPatternEvaluator;
 import com.google.devtools.build.lib.pkgcache.TransitivePackageLoader;
 import com.google.devtools.build.lib.profiler.AutoProfiler;
-import com.google.devtools.build.lib.query2.engine.Callback;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment;
 import com.google.devtools.build.lib.query2.engine.QueryEvalResult;
 import com.google.devtools.build.lib.query2.engine.QueryException;
 import com.google.devtools.build.lib.query2.engine.QueryExpression;
+import com.google.devtools.build.lib.query2.engine.QueryUtil;
 import com.google.devtools.build.lib.util.BinaryPredicate;
 import com.google.devtools.build.skyframe.WalkableGraph.WalkableGraphFactory;
 
@@ -46,7 +45,6 @@ import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
@@ -138,11 +136,10 @@ public abstract class AbstractBlazeQueryEnvironment<T> implements QueryEnvironme
    * @throws QueryException if the evaluation failed and {@code --nokeep_going} was in
    *   effect
    */
-  public QueryEvalResult evaluateQuery(QueryExpression expr, final Callback<T> callback)
+  public QueryEvalResult<T> evaluateQuery(QueryExpression expr)
       throws QueryException, InterruptedException {
-
-    final AtomicBoolean empty = new AtomicBoolean(true);
-    try (final AutoProfiler p = AutoProfiler.logged("evaluating query", LOG)) {
+    Set<T> resultNodes;
+    try (AutoProfiler p = AutoProfiler.logged("evaluating query", LOG)) {
       resolvedTargetPatterns.clear();
 
       // In the --nokeep_going case, errors are reported in the order in which the patterns are
@@ -155,15 +152,9 @@ public abstract class AbstractBlazeQueryEnvironment<T> implements QueryEnvironme
         // Unfortunately, by evaluating the patterns in parallel, we lose some location information.
         throw new QueryException(expr, e.getMessage());
       }
+
       try {
-        this.eval(expr, new Callback<T>() {
-          @Override
-          public void process(Iterable<T> partialResult)
-              throws QueryException, InterruptedException {
-            empty.compareAndSet(true, Iterables.isEmpty(partialResult));
-            callback.process(partialResult);
-          }
-        });
+        resultNodes = QueryUtil.evalAll(this, expr);
       } catch (QueryException e) {
         throw new QueryException(e, expr);
       }
@@ -181,12 +172,12 @@ public abstract class AbstractBlazeQueryEnvironment<T> implements QueryEnvironme
       }
     }
 
-    return new QueryEvalResult(!eventHandler.hasErrors(), empty.get());
+    return new QueryEvalResult<>(!eventHandler.hasErrors(), resultNodes);
   }
 
-  public QueryEvalResult evaluateQuery(String query, Callback<T> callback)
+  public QueryEvalResult<T> evaluateQuery(String query)
       throws QueryException, InterruptedException {
-    return evaluateQuery(QueryExpression.parse(query, this), callback);
+    return evaluateQuery(QueryExpression.parse(query, this));
   }
 
   @Override
diff --git a/src/main/java/com/google/devtools/build/lib/query2/BUILD b/src/main/java/com/google/devtools/build/lib/query2/BUILD
index 306ef7ad65..a5edb8e972 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/query2/BUILD
@@ -44,7 +44,6 @@ java_library(
     srcs = glob(["engine/*.java"]),
     deps = [
         "//src/main/java/com/google/devtools/build/lib:common",
-        "//src/main/java/com/google/devtools/build/lib:concurrent",
         "//src/main/java/com/google/devtools/build/lib:graph",
         "//src/main/java/com/google/devtools/build/lib:util",
         "//third_party:jsr305",
diff --git a/src/main/java/com/google/devtools/build/lib/query2/BlazeQueryEnvironment.java b/src/main/java/com/google/devtools/build/lib/query2/BlazeQueryEnvironment.java
index db006b540c..55b1bc7be5 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/BlazeQueryEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/BlazeQueryEnvironment.java
@@ -37,8 +37,8 @@ import com.google.devtools.build.lib.pkgcache.TargetEdgeObserver;
 import com.google.devtools.build.lib.pkgcache.TargetPatternEvaluator;
 import com.google.devtools.build.lib.pkgcache.TargetProvider;
 import com.google.devtools.build.lib.pkgcache.TransitivePackageLoader;
+import com.google.devtools.build.lib.query2.engine.BlazeQueryEvalResult;
 import com.google.devtools.build.lib.query2.engine.Callback;
-import com.google.devtools.build.lib.query2.engine.DigraphQueryEvalResult;
 import com.google.devtools.build.lib.query2.engine.QueryEvalResult;
 import com.google.devtools.build.lib.query2.engine.QueryException;
 import com.google.devtools.build.lib.query2.engine.QueryExpression;
@@ -54,7 +54,6 @@ import java.util.Iterator;
 import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Set;
-import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
  * The environment of a Blaze query. Not thread-safe.
@@ -103,22 +102,15 @@ public class BlazeQueryEnvironment extends AbstractBlazeQueryEnvironment<Target>
   }
 
   @Override
-  public DigraphQueryEvalResult<Target> evaluateQuery(QueryExpression expr,
-      final Callback<Target> callback) throws QueryException, InterruptedException {
+  public BlazeQueryEvalResult<Target> evaluateQuery(QueryExpression expr)
+      throws QueryException, InterruptedException {
     // Some errors are reported as QueryExceptions and others as ERROR events (if --keep_going). The
     // result is set to have an error iff there were errors emitted during the query, so we reset
     // errors here.
     eventHandler.resetErrors();
-    final AtomicBoolean empty = new AtomicBoolean(true);
-    QueryEvalResult queryEvalResult = super.evaluateQuery(expr, new Callback<Target>() {
-      @Override
-      public void process(Iterable<Target> partialResult)
-          throws QueryException, InterruptedException {
-        empty.compareAndSet(true, Iterables.isEmpty(partialResult));
-        callback.process(partialResult);
-      }
-    });
-    return new DigraphQueryEvalResult<>(queryEvalResult.getSuccess(), empty.get(), graph);
+    QueryEvalResult<Target> queryEvalResult = super.evaluateQuery(expr);
+    return new BlazeQueryEvalResult<>(queryEvalResult.getSuccess(), queryEvalResult.getResultSet(),
+        graph);
   }
 
   @Override
diff --git a/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java b/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
index 5cb7a326b3..85d96ecf95 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
@@ -167,14 +167,14 @@ public class SkyQueryEnvironment extends AbstractBlazeQueryEnvironment<Target> {
   }
 
   @Override
-  public QueryEvalResult evaluateQuery(QueryExpression expr, Callback<Target> callback)
+  public QueryEvalResult<Target> evaluateQuery(QueryExpression expr)
       throws QueryException, InterruptedException {
     // Some errors are reported as QueryExceptions and others as ERROR events (if --keep_going). The
     // result is set to have an error iff there were errors emitted during the query, so we reset
     // errors here.
     eventHandler.resetErrors();
     init();
-    return super.evaluateQuery(expr, callback);
+    return super.evaluateQuery(expr);
   }
 
   private Map<Target, Collection<Target>> makeTargetsMap(Map<SkyKey, Iterable<SkyKey>> input) {
@@ -376,7 +376,7 @@ public class SkyQueryEnvironment extends AbstractBlazeQueryEnvironment<Target> {
     }
   }
 
-  private static Target getSubincludeTarget(Label label, Package pkg) {
+  private static Target getSubincludeTarget(final Label label, Package pkg) {
     return new FakeSubincludeTarget(label, pkg);
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/query2/engine/DigraphQueryEvalResult.java b/src/main/java/com/google/devtools/build/lib/query2/engine/BlazeQueryEvalResult.java
index 24612b25e3..4ad13573f9 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/engine/DigraphQueryEvalResult.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/engine/BlazeQueryEvalResult.java
@@ -17,18 +17,20 @@ package com.google.devtools.build.lib.query2.engine;
 import com.google.common.base.Preconditions;
 import com.google.devtools.build.lib.graph.Digraph;
 
+import java.util.Set;
+
 /** {@link QueryEvalResult} along with a digraph giving the structure of the results. */
-public class DigraphQueryEvalResult<T> extends QueryEvalResult {
+public class BlazeQueryEvalResult<T> extends QueryEvalResult<T> {
 
   private final Digraph<T> graph;
 
-  public DigraphQueryEvalResult(boolean success, boolean isEmpty, Digraph<T> graph) {
-    super(success, isEmpty);
+  public BlazeQueryEvalResult(boolean success, Set<T> resultSet, Digraph<T> graph) {
+    super(success, resultSet);
     this.graph = Preconditions.checkNotNull(graph);
   }
 
-  /** Returns the recorded graph */
-  public Digraph<T> getGraph() {
-    return graph;
+  /** Returns the result as a directed graph over elements. */
+  public Digraph<T> getResultGraph() {
+    return graph.extractSubgraph(resultSet);
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/query2/engine/OutputFormatterCallback.java b/src/main/java/com/google/devtools/build/lib/query2/engine/OutputFormatterCallback.java
deleted file mode 100644
index 546b0d51bb..0000000000
--- a/src/main/java/com/google/devtools/build/lib/query2/engine/OutputFormatterCallback.java
+++ /dev/null
@@ -1,93 +0,0 @@
-// Copyright 2015 The Bazel Authors. All rights reserved.
-//
-// 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 com.google.devtools.build.lib.query2.engine;
-
-import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadCompatible;
-
-import java.io.Closeable;
-import java.io.IOException;
-
-import javax.annotation.Nullable;
-
-/** A callback that can receive a finish event when there are no more partial results */
-@ThreadCompatible
-public abstract class OutputFormatterCallback<T> implements Callback<T>, Closeable {
-
-  private IOException ioException;
-
-  /**
-   * This method will be called before any partial result are available.
-   *
-   * <p>It should be used for opening resources or sending a header to the output.
-   */
-  public void start() throws IOException { }
-
-  /**
-   * Same as start but for closing resources or writting a footer.
-   *
-   * <p>Will be called even in the case of an error.
-   */
-  @Override
-  public void close() throws IOException{}
-
-  /**
-   * Note that {@link Callback} interface does not throw IOExceptions. What this implementation does
-   * instead is throw {@code InterruptedException} and store the {@code IOException} in the {@code
-   * ioException} field. Users of this class should check on InterruptedException the field to
-   * disambiguate between real interruptions or IO Exceptions.
-   */
-  @Override
-  public final void process(Iterable<T> partialResult) throws QueryException, InterruptedException {
-    try {
-      processOutput(partialResult);
-    } catch (IOException e) {
-      ioException = e;
-      throw new InterruptedException("Interrupting due to a IOException in the OutputFormatter");
-    }
-  }
-
-  protected abstract void processOutput(Iterable<T> partialResult)
-      throws IOException, InterruptedException;
-
-  @Nullable
-  public IOException getIoException() {
-    return ioException;
-  }
-
-  /**
-   * Use an {@code OutputFormatterCallback} with an already computed set of targets. Note that this
-   * does not work in stream mode, as the {@code targets} would already be computed.
-   *
-   * <p>The intended usage of this method is to use {@code StreamedFormatter} formaters in non
-   * streaming contexts.
-   */
-  public static <T> void processAllTargets(OutputFormatterCallback<T> callback,
-      Iterable<T> targets) throws IOException, InterruptedException {
-    try {
-      callback.start();
-      callback.process(targets);
-    } catch (InterruptedException e) {
-      IOException ioException = callback.getIoException();
-      if (ioException != null) {
-        throw ioException;
-      }
-      throw e;
-    } catch (QueryException e) {
-      throw new IllegalStateException("This should not happen, as we are not running any query,"
-          + " only printing the results:" + e.getMessage(), e);
-    } finally {
-      callback.close();
-    }
-  }
-}
diff --git a/src/main/java/com/google/devtools/build/lib/query2/engine/QueryEvalResult.java b/src/main/java/com/google/devtools/build/lib/query2/engine/QueryEvalResult.java
index 886cb439fe..23e77e6758 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/engine/QueryEvalResult.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/engine/QueryEvalResult.java
@@ -14,18 +14,24 @@
 
 package com.google.devtools.build.lib.query2.engine;
 
+import com.google.common.base.Preconditions;
+
+import java.util.Set;
+
 /**
- * Information about the query evaluation, like if it was successful and number of elements
- * returned.
+ * The result of a query evaluation, containing a set of elements.
+ *
+ * @param <T> the node type of the elements.
  */
-public class QueryEvalResult {
+public class QueryEvalResult<T> {
 
-  private final boolean success;
-  private final boolean empty;
+  protected final boolean success;
+  protected final Set<T> resultSet;
 
-  public QueryEvalResult(boolean success, boolean empty) {
+  public QueryEvalResult(
+      boolean success, Set<T> resultSet) {
     this.success = success;
-    this.empty = empty;
+    this.resultSet = Preconditions.checkNotNull(resultSet);
   }
 
   /**
@@ -36,13 +42,16 @@ public class QueryEvalResult {
     return success;
   }
 
-  /** True if the query did not return any result; */
-  public boolean isEmpty() {
-    return empty;
+  /**
+   * Returns the result as a set of targets.
+   */
+  public Set<T> getResultSet() {
+    return resultSet;
   }
 
   @Override
   public String toString() {
-    return (getSuccess() ? "Successful" : "Unsuccessful") + ", empty = " + empty;
+    return (getSuccess() ? "Successful" : "Unsuccessful") + ", result size = "
+        + getResultSet().size() + ", " + getResultSet();
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/query2/output/OutputFormatter.java b/src/main/java/com/google/devtools/build/lib/query2/output/OutputFormatter.java
index a6351d4df9..93d28bbd50 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/output/OutputFormatter.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/output/OutputFormatter.java
@@ -20,7 +20,6 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Sets;
 import com.google.devtools.build.lib.cmdline.Label;
-import com.google.devtools.build.lib.collect.CompactHashSet;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.graph.Digraph;
 import com.google.devtools.build.lib.graph.Node;
@@ -28,7 +27,6 @@ import com.google.devtools.build.lib.packages.Attribute;
 import com.google.devtools.build.lib.packages.AttributeSerializer;
 import com.google.devtools.build.lib.packages.Rule;
 import com.google.devtools.build.lib.packages.Target;
-import com.google.devtools.build.lib.query2.engine.OutputFormatterCallback;
 import com.google.devtools.build.lib.query2.output.QueryOptions.OrderOutput;
 import com.google.devtools.build.lib.syntax.EvalUtils;
 import com.google.devtools.build.lib.syntax.Printer;
@@ -155,20 +153,17 @@ public abstract class OutputFormatter implements Serializable {
       AspectResolver aspectProvider) throws IOException, InterruptedException;
 
   /**
-   * Unordered streamed output formatter (wrt. dependency ordering).
+   * Unordered output formatter (wrt. dependency ordering).
    *
-   * <p>Formatters that support streamed output may be used when only the set of query results is
+   * <p>Formatters that support unordered output may be used when only the set of query results is
    * requested but their ordering is irrelevant.
    *
-   * <p>The benefit of using a streamed formatter is that we can save the potentially expensive
-   * subgraph extraction step before presenting the query results and that depending on the query
-   * environment used, it can be more memory performant, as it does not aggregate all the data
-   * before writting in the output.
+   * <p>The benefit of using a unordered formatter is that we can save the potentially expensive
+   * subgraph extraction step before presenting the query results.
    */
-  public interface StreamedFormatter {
-
-    OutputFormatterCallback<Target> createStreamCallback(QueryOptions options, PrintStream out,
-        AspectResolver aspectResolver);
+  public interface UnorderedFormatter {
+    void outputUnordered(QueryOptions options, Iterable<Target> result, PrintStream out,
+        AspectResolver aspectResolver) throws IOException, InterruptedException;
   }
 
   /**
@@ -177,8 +172,8 @@ public abstract class OutputFormatter implements Serializable {
   public abstract String getName();
 
   abstract static class AbstractUnorderedFormatter extends OutputFormatter
-      implements StreamedFormatter {
-    protected Iterable<Target> getOrderedTargets(
+      implements UnorderedFormatter {
+    private static Iterable<Target> getOrderedTargets(
         Digraph<Target> result, QueryOptions options) {
       Iterable<Node<Target>> orderedResult =
           options.orderOutput == OrderOutput.DEPS
@@ -188,11 +183,13 @@ public abstract class OutputFormatter implements Serializable {
     }
 
     @Override
-    public void output(QueryOptions options, Digraph<Target> result, PrintStream out,
-        AspectResolver aspectResolver) throws IOException, InterruptedException {
-      OutputFormatterCallback.processAllTargets(
-          createStreamCallback(options, out, aspectResolver),
-          getOrderedTargets(result, options));
+    public void output(
+        QueryOptions options,
+        Digraph<Target> result,
+        PrintStream out,
+        AspectResolver aspectResolver)
+        throws IOException, InterruptedException {
+      outputUnordered(options, getOrderedTargets(result, options), out, aspectResolver);
     }
   }
 
@@ -204,7 +201,7 @@ public abstract class OutputFormatter implements Serializable {
 
     private final boolean showKind;
 
-    private LabelOutputFormatter(boolean showKind) {
+    public LabelOutputFormatter(boolean showKind) {
       this.showKind = showKind;
     }
 
@@ -214,22 +211,15 @@ public abstract class OutputFormatter implements Serializable {
     }
 
     @Override
-    public OutputFormatterCallback<Target> createStreamCallback(QueryOptions options,
-        final PrintStream out, AspectResolver aspectResolver) {
-      return new OutputFormatterCallback<Target>() {
-
-        @Override
-        protected void processOutput(Iterable<Target> partialResult)
-            throws IOException, InterruptedException {
-          for (Target target : partialResult) {
-            if (showKind) {
-              out.print(target.getTargetKind());
-              out.print(' ');
-            }
-            out.println(target.getLabel());
-          }
+    public void outputUnordered(QueryOptions options, Iterable<Target> result, PrintStream out,
+        AspectResolver aspectResolver) {
+      for (Target target : result) {
+        if (showKind) {
+          out.print(target.getTargetKind());
+          out.print(' ');
         }
-      };
+        out.println(target.getLabel());
+      }
     }
   }
 
@@ -255,28 +245,15 @@ public abstract class OutputFormatter implements Serializable {
     }
 
     @Override
-    public OutputFormatterCallback<Target> createStreamCallback(QueryOptions options,
-        final PrintStream out,
+    public void outputUnordered(QueryOptions options, Iterable<Target> result, PrintStream out,
         AspectResolver aspectResolver) {
-      return new OutputFormatterCallback<Target>() {
-        private final Set<String> packageNames = Sets.newTreeSet();
-
-        @Override
-        protected void processOutput(Iterable<Target> partialResult)
-            throws IOException, InterruptedException {
-
-          for (Target target : partialResult) {
-            packageNames.add(target.getLabel().getPackageName());
-          }
-        }
-
-        @Override
-        public void close() throws IOException {
-          for (String packageName : packageNames) {
-            out.println(packageName);
-          }
-        }
-      };
+      Set<String> packageNames = Sets.newTreeSet();
+      for (Target target : result) {
+        packageNames.add(target.getLabel().getPackageName());
+      }
+      for (String packageName : packageNames) {
+        out.println(packageName);
+      }
     }
   }
 
@@ -293,20 +270,12 @@ public abstract class OutputFormatter implements Serializable {
     }
 
     @Override
-    public OutputFormatterCallback<Target> createStreamCallback(QueryOptions options,
-        final PrintStream out,
+    public void outputUnordered(QueryOptions options, Iterable<Target> result, PrintStream out,
         AspectResolver aspectResolver) {
-      return new OutputFormatterCallback<Target>() {
-
-        @Override
-        protected void processOutput(Iterable<Target> partialResult)
-            throws IOException, InterruptedException {
-          for (Target target : partialResult) {
-            Location location = target.getLocation();
-            out.println(location.print() + ": " + target.getTargetKind() + " " + target.getLabel());
-          }
-        }
-      };
+      for (Target target : result) {
+        Location location = target.getLocation();
+        out.println(location.print()  + ": " + target.getTargetKind() + " " + target.getLabel());
+      }
     }
   }
 
@@ -321,57 +290,48 @@ public abstract class OutputFormatter implements Serializable {
       return "build";
     }
 
-    @Override
-    public OutputFormatterCallback<Target> createStreamCallback(QueryOptions options,
-        final PrintStream out,
-        AspectResolver aspectResolver) {
-      return new OutputFormatterCallback<Target>() {
-        private final Set<Label> printed = CompactHashSet.create();
-
-        private void outputRule(Rule rule, PrintStream out) {
-          out.printf("# %s%n", rule.getLocation());
-          out.printf("%s(%n", rule.getRuleClass());
-          out.printf("  name = \"%s\",%n", rule.getName());
-
-          for (Attribute attr : rule.getAttributes()) {
-            Pair<Iterable<Object>, AttributeValueSource> values = getAttributeValues(rule, attr);
-            if (Iterables.size(values.first) != 1) {
-              continue;  // TODO(bazel-team): handle configurable attributes.
-            }
-            if (values.second != AttributeValueSource.RULE) {
-              continue;  // Don't print default values.
-            }
-            Object value = Iterables.getOnlyElement(values.first);
-            out.printf("  %s = ", attr.getPublicName());
-            if (value instanceof Label) {
-              value = value.toString();
-            } else if (value instanceof List<?> && EvalUtils.isImmutable(value)) {
-              // Display it as a list (and not as a tuple). Attributes can never be tuples.
-              value = new ArrayList<>((List<?>) value);
-            }
-            // It is *much* faster to write to a StringBuilder compared to the PrintStream object.
-            StringBuilder builder = new StringBuilder();
-            Printer.write(builder, value);
-            out.print(builder);
-            out.println(",");
-          }
-          out.printf(")\n%n");
-        }
+    private void outputRule(Rule rule, PrintStream out) {
+      out.printf("# %s%n", rule.getLocation());
+      out.printf("%s(%n", rule.getRuleClass());
+      out.printf("  name = \"%s\",%n", rule.getName());
 
-        @Override
-        protected void processOutput(Iterable<Target> partialResult)
-            throws IOException, InterruptedException {
+      for (Attribute attr : rule.getAttributes()) {
+        Pair<Iterable<Object>, AttributeValueSource> values = getAttributeValues(rule, attr);
+        if (Iterables.size(values.first) != 1) {
+          continue;  // TODO(bazel-team): handle configurable attributes.
+        }
+        if (values.second != AttributeValueSource.RULE) {
+          continue;  // Don't print default values.
+        }
+        Object value = Iterables.getOnlyElement(values.first);
+        out.printf("  %s = ", attr.getPublicName());
+        if (value instanceof Label) {
+          value = value.toString();
+        } else if (value instanceof List<?> && EvalUtils.isImmutable(value)) {
+          // Display it as a list (and not as a tuple). Attributes can never be tuples.
+          value = new ArrayList<>((List<?>) value);
+        }
+        // It is *much* faster to write to a StringBuilder compared to the PrintStream object.
+        StringBuilder builder = new StringBuilder();
+        Printer.write(builder, value);
+        out.print(builder);
+        out.println(",");
+      }
+      out.printf(")\n%n");
+    }
 
-          for (Target target : partialResult) {
-            Rule rule = target.getAssociatedRule();
-            if (rule == null || printed.contains(rule.getLabel())) {
-              continue;
-            }
-            outputRule(rule, out);
-            printed.add(rule.getLabel());
-          }
+    @Override
+    public void outputUnordered(QueryOptions options, Iterable<Target> result, PrintStream out,
+        AspectResolver aspectResolver) {
+      Set<Label> printed = new HashSet<>();
+      for (Target target : result) {
+        Rule rule = target.getAssociatedRule();
+        if (rule == null || printed.contains(rule.getLabel())) {
+          continue;
         }
-      };
+        outputRule(rule, out);
+        printed.add(rule.getLabel());
+      }
     }
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/query2/output/ProtoOutputFormatter.java b/src/main/java/com/google/devtools/build/lib/query2/output/ProtoOutputFormatter.java
index 8fc130177e..815f9152bf 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/output/ProtoOutputFormatter.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/output/ProtoOutputFormatter.java
@@ -34,12 +34,10 @@ import com.google.devtools.build.lib.packages.ProtoUtils;
 import com.google.devtools.build.lib.packages.Rule;
 import com.google.devtools.build.lib.packages.Target;
 import com.google.devtools.build.lib.query2.FakeSubincludeTarget;
-import com.google.devtools.build.lib.query2.engine.OutputFormatterCallback;
 import com.google.devtools.build.lib.query2.output.AspectResolver.BuildFileDependencyMode;
-import com.google.devtools.build.lib.query2.output.OutputFormatter.AbstractUnorderedFormatter;
+import com.google.devtools.build.lib.query2.output.OutputFormatter.UnorderedFormatter;
 import com.google.devtools.build.lib.query2.output.QueryOptions.OrderOutput;
 import com.google.devtools.build.lib.query2.proto.proto2api.Build;
-import com.google.devtools.build.lib.query2.proto.proto2api.Build.QueryResult.Builder;
 import com.google.devtools.build.lib.syntax.Environment;
 import com.google.devtools.build.lib.util.BinaryPredicate;
 
@@ -56,7 +54,7 @@ import java.util.Set;
  * By taking the bytes and calling {@code mergeFrom()} on a
  * {@code Build.QueryResult} object the full result can be reconstructed.
  */
-public class ProtoOutputFormatter extends AbstractUnorderedFormatter {
+public class ProtoOutputFormatter extends OutputFormatter implements UnorderedFormatter {
 
   /**
    * A special attribute name for the rule implementation hash code.
@@ -79,36 +77,19 @@ public class ProtoOutputFormatter extends AbstractUnorderedFormatter {
   }
 
   @Override
-  public OutputFormatterCallback<Target> createStreamCallback(QueryOptions options,
-      final PrintStream out, AspectResolver aspectResolver) {
+  public void outputUnordered(QueryOptions options, Iterable<Target> result, PrintStream out,
+      AspectResolver aspectResolver) throws IOException, InterruptedException {
     relativeLocations = options.relativeLocations;
     this.aspectResolver = aspectResolver;
     this.includeDefaultValues = options.protoIncludeDefaultValues;
     setDependencyFilter(options);
 
-    return new OutputFormatterCallback<Target>() {
-
-      private Builder queryResult;
-
-      @Override
-      public void start() {
-        queryResult = Build.QueryResult.newBuilder();
-      }
-
-      @Override
-      protected void processOutput(Iterable<Target> partialResult)
-          throws IOException, InterruptedException {
-
-        for (Target target : partialResult) {
-          queryResult.addTarget(toTargetProtoBuffer(target));
-        }
-      }
+    Build.QueryResult.Builder queryResult = Build.QueryResult.newBuilder();
+    for (Target target : result) {
+      addTarget(queryResult, target);
+    }
 
-      @Override
-      public void close() throws IOException {
-        queryResult.build().writeTo(out);
-      }
-    };
+    queryResult.build().writeTo(out);
   }
 
   private static Iterable<Target> getSortedLabels(Digraph<Target> result) {
@@ -117,8 +98,24 @@ public class ProtoOutputFormatter extends AbstractUnorderedFormatter {
   }
 
   @Override
-  protected Iterable<Target> getOrderedTargets(Digraph<Target> result, QueryOptions options) {
-    return options.orderOutput == OrderOutput.FULL ? getSortedLabels(result) : result.getLabels();
+  public void output(QueryOptions options, Digraph<Target> result, PrintStream out,
+      AspectResolver aspectResolver) throws IOException, InterruptedException {
+    outputUnordered(
+        options,
+        options.orderOutput == OrderOutput.FULL ? getSortedLabels(result) : result.getLabels(),
+        out,
+        aspectResolver);
+  }
+
+  /**
+   * Add the target to the query result.
+   * @param queryResult The query result that contains all rule, input and
+   *   output targets.
+   * @param target The query target being converted to a protocol buffer.
+   */
+  private void addTarget(Build.QueryResult.Builder queryResult, Target target)
+      throws InterruptedException {
+    queryResult.addTarget(toTargetProtoBuffer(target));
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/query2/output/QueryOutputUtils.java b/src/main/java/com/google/devtools/build/lib/query2/output/QueryOutputUtils.java
index 1533b7bf43..36f5464461 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/output/QueryOutputUtils.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/output/QueryOutputUtils.java
@@ -14,43 +14,32 @@
 package com.google.devtools.build.lib.query2.output;
 
 import com.google.devtools.build.lib.packages.Target;
-import com.google.devtools.build.lib.query2.engine.DigraphQueryEvalResult;
-import com.google.devtools.build.lib.query2.engine.OutputFormatterCallback;
+import com.google.devtools.build.lib.query2.engine.BlazeQueryEvalResult;
 import com.google.devtools.build.lib.query2.engine.QueryEvalResult;
-import com.google.devtools.build.lib.query2.output.OutputFormatter.StreamedFormatter;
+import com.google.devtools.build.lib.query2.output.OutputFormatter.UnorderedFormatter;
 import com.google.devtools.build.lib.query2.output.QueryOptions.OrderOutput;
 
 import java.io.IOException;
 import java.io.PrintStream;
-import java.util.Set;
 
 /** Static utility methods for outputting a query. */
 public class QueryOutputUtils {
   // Utility class cannot be instantiated.
   private QueryOutputUtils() {}
 
-  public static boolean shouldStreamResults(QueryOptions queryOptions, OutputFormatter formatter) {
-    return queryOptions.orderOutput == OrderOutput.NO
-        && formatter instanceof StreamedFormatter;
+  public static boolean orderResults(QueryOptions queryOptions, OutputFormatter formatter) {
+    return queryOptions.orderOutput != OrderOutput.NO || !(formatter instanceof UnorderedFormatter);
   }
 
-  public static void output(QueryOptions queryOptions, QueryEvalResult result,
-      Set<Target> targetsResult, OutputFormatter formatter, PrintStream outputStream,
-      AspectResolver aspectResolver)
+  public static void output(QueryOptions queryOptions, QueryEvalResult<Target> result,
+      OutputFormatter formatter, PrintStream outputStream, AspectResolver aspectResolver)
       throws IOException, InterruptedException {
-    /*
-     * This is not really streaming, but we are using the streaming interface for writing into the
-     * output everything in one batch. This happens when the QueryEnvironment does not
-     * support streaming but we don't care about ordered results.
-     */
-    boolean orderedResults = !shouldStreamResults(queryOptions, formatter);
-    if (orderedResults) {
-      formatter.output(queryOptions,
-          ((DigraphQueryEvalResult<Target>) result).getGraph().extractSubgraph(targetsResult),
+    if (orderResults(queryOptions, formatter)) {
+      formatter.output(queryOptions, ((BlazeQueryEvalResult<Target>) result).getResultGraph(),
           outputStream, aspectResolver);
     } else {
-      OutputFormatterCallback.processAllTargets(((StreamedFormatter) formatter)
-          .createStreamCallback(queryOptions, outputStream, aspectResolver), targetsResult);
+      ((UnorderedFormatter) formatter).outputUnordered(queryOptions, result.getResultSet(),
+          outputStream, aspectResolver);
     }
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/query2/output/XmlOutputFormatter.java b/src/main/java/com/google/devtools/build/lib/query2/output/XmlOutputFormatter.java
index 2af71b7414..b8b4466bad 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/output/XmlOutputFormatter.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/output/XmlOutputFormatter.java
@@ -27,7 +27,6 @@ import com.google.devtools.build.lib.packages.PackageGroup;
 import com.google.devtools.build.lib.packages.Rule;
 import com.google.devtools.build.lib.packages.Target;
 import com.google.devtools.build.lib.query2.FakeSubincludeTarget;
-import com.google.devtools.build.lib.query2.engine.OutputFormatterCallback;
 import com.google.devtools.build.lib.query2.output.AspectResolver.BuildFileDependencyMode;
 import com.google.devtools.build.lib.query2.output.OutputFormatter.AbstractUnorderedFormatter;
 import com.google.devtools.build.lib.util.BinaryPredicate;
@@ -37,7 +36,6 @@ import org.w3c.dom.DOMException;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 
-import java.io.IOException;
 import java.io.PrintStream;
 import java.util.Collection;
 import java.util.HashSet;
@@ -59,9 +57,11 @@ import javax.xml.transform.stream.StreamResult;
  */
 class XmlOutputFormatter extends AbstractUnorderedFormatter {
 
-  private QueryOptions options;
-  private AspectResolver aspectResolver;
-  private BinaryPredicate<Rule, Attribute> dependencyFilter;
+  private boolean xmlLineNumbers;
+  private boolean showDefaultValues;
+  private boolean relativeLocations;
+  private transient AspectResolver aspectResolver;
+  private transient BinaryPredicate<Rule, Attribute> dependencyFilter;
 
   @Override
   public String getName() {
@@ -69,52 +69,36 @@ class XmlOutputFormatter extends AbstractUnorderedFormatter {
   }
 
   @Override
-  public OutputFormatterCallback<Target> createStreamCallback(QueryOptions options,
-      final PrintStream out, AspectResolver aspectResolver) {
-    this.options = options;
-    this.aspectResolver = aspectResolver;
+  public void outputUnordered(QueryOptions options, Iterable<Target> result, PrintStream out,
+      AspectResolver aspectResolver) throws InterruptedException {
+    this.xmlLineNumbers = options.xmlLineNumbers;
+    this.showDefaultValues = options.xmlShowDefaultValues;
+    this.relativeLocations = options.relativeLocations;
     this.dependencyFilter = OutputFormatter.getDependencyFilter(options);
-    return new OutputFormatterCallback<Target>() {
-
-      private Document doc;
-      private Element queryElem;
-
-
-      @Override
-      public void start() {
-        try {
-          DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
-          doc = factory.newDocumentBuilder().newDocument();
-        } catch (ParserConfigurationException e) {
-          // This shouldn't be possible: all the configuration is hard-coded.
-          throw new IllegalStateException("XML output failed", e);
-        }
-        doc.setXmlVersion("1.1");
-        queryElem = doc.createElement("query");
-        queryElem.setAttribute("version", "2");
-        doc.appendChild(queryElem);
-      }
-
-      @Override
-      protected void processOutput(Iterable<Target> partialResult)
-          throws IOException, InterruptedException {
-        for (Target target : partialResult) {
-          queryElem.appendChild(createTargetElement(doc, target));
-        }
-      }
-
-      @Override
-      public void close() throws IOException {
-        try {
-          Transformer transformer = TransformerFactory.newInstance().newTransformer();
-          transformer.setOutputProperty(OutputKeys.INDENT, "yes");
-          transformer.transform(new DOMSource(doc), new StreamResult(out));
-        } catch (TransformerFactoryConfigurationError | TransformerException e) {
-          // This shouldn't be possible: all the configuration is hard-coded.
-          throw new IllegalStateException("XML output failed", e);
-        }
-      }
-    };
+    this.aspectResolver = aspectResolver;
+    Document doc;
+    try {
+      DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
+      doc = factory.newDocumentBuilder().newDocument();
+    } catch (ParserConfigurationException e) {
+      // This shouldn't be possible: all the configuration is hard-coded.
+      throw new IllegalStateException("XML output failed",  e);
+    }
+    doc.setXmlVersion("1.1");
+    Element queryElem = doc.createElement("query");
+    queryElem.setAttribute("version", "2");
+    doc.appendChild(queryElem);
+    for (Target target : result) {
+      queryElem.appendChild(createTargetElement(doc, target));
+    }
+    try {
+      Transformer transformer = TransformerFactory.newInstance().newTransformer();
+      transformer.setOutputProperty(OutputKeys.INDENT, "yes");
+      transformer.transform(new DOMSource(doc), new StreamResult(out));
+    } catch (TransformerFactoryConfigurationError | TransformerException e) {
+      // This shouldn't be possible: all the configuration is hard-coded.
+      throw new IllegalStateException("XML output failed",  e);
+    }
   }
 
   /**
@@ -136,9 +120,9 @@ class XmlOutputFormatter extends AbstractUnorderedFormatter {
       Rule rule = (Rule) target;
       elem = doc.createElement("rule");
       elem.setAttribute("class", rule.getRuleClass());
-      for (Attribute attr : rule.getAttributes()) {
+      for (Attribute attr: rule.getAttributes()) {
         Pair<Iterable<Object>, AttributeValueSource> values = getAttributeValues(rule, attr);
-        if (values.second == AttributeValueSource.RULE || options.xmlShowDefaultValues) {
+        if (values.second == AttributeValueSource.RULE || showDefaultValues) {
           Element attrElem = createValueElement(doc, attr.getType(), values.first);
           attrElem.setAttribute("name", attr.getName());
           elem.appendChild(attrElem);
@@ -221,8 +205,8 @@ class XmlOutputFormatter extends AbstractUnorderedFormatter {
     }
 
     elem.setAttribute("name", target.getLabel().toString());
-    String location = getLocation(target, options.relativeLocations);
-    if (!options.xmlLineNumbers) {
+    String location = getLocation(target, relativeLocations);
+    if (!xmlLineNumbers) {
       int firstColon = location.indexOf(':');
       if (firstColon != -1) {
         location = location.substring(0, firstColon);
diff --git a/src/main/java/com/google/devtools/build/lib/rules/genquery/GenQuery.java b/src/main/java/com/google/devtools/build/lib/rules/genquery/GenQuery.java
index 76eac71bcf..13d5be4dd8 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/genquery/GenQuery.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/genquery/GenQuery.java
@@ -49,11 +49,10 @@ import com.google.devtools.build.lib.pkgcache.FilteringPolicy;
 import com.google.devtools.build.lib.pkgcache.PackageProvider;
 import com.google.devtools.build.lib.pkgcache.TargetPatternEvaluator;
 import com.google.devtools.build.lib.query2.AbstractBlazeQueryEnvironment;
-import com.google.devtools.build.lib.query2.engine.DigraphQueryEvalResult;
+import com.google.devtools.build.lib.query2.engine.BlazeQueryEvalResult;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryFunction;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.Setting;
 import com.google.devtools.build.lib.query2.engine.QueryException;
-import com.google.devtools.build.lib.query2.engine.QueryUtil.AggregateAllCallback;
 import com.google.devtools.build.lib.query2.engine.SkyframeRestartQueryException;
 import com.google.devtools.build.lib.query2.output.OutputFormatter;
 import com.google.devtools.build.lib.query2.output.QueryOptions;
@@ -261,9 +260,8 @@ public class GenQuery implements RuleConfiguredTargetFactory {
                          String query, RuleContext ruleContext)
       throws InterruptedException {
 
-    DigraphQueryEvalResult<Target> queryResult;
+    BlazeQueryEvalResult<Target> queryResult;
     OutputFormatter formatter;
-    AggregateAllCallback<Target> targets = new AggregateAllCallback<>();
     try {
       Set<Setting> settings = queryOptions.toSettings();
 
@@ -285,20 +283,20 @@ public class GenQuery implements RuleConfiguredTargetFactory {
       // All the packages are already loaded at this point, so there is no need
       // to start up many threads. 4 are started up to make good use of multiple
       // cores.
-      queryResult = (DigraphQueryEvalResult<Target>) AbstractBlazeQueryEnvironment
+      queryResult = (BlazeQueryEvalResult<Target>) AbstractBlazeQueryEnvironment
           .newQueryEnvironment(
               /*transitivePackageLoader=*/null, /*graph=*/null, packageProvider,
               evaluator,
               /*keepGoing=*/false,
               ruleContext.attributes().get("strict", Type.BOOLEAN),
-              /*orderedResults=*/!QueryOutputUtils.shouldStreamResults(queryOptions, formatter),
+              /*orderedResults=*/QueryOutputUtils.orderResults(queryOptions, formatter),
               /*universeScope=*/ImmutableList.<String>of(),
               /*loadingPhaseThreads=*/4,
               labelFilter,
               getEventHandler(ruleContext),
               settings,
               ImmutableList.<QueryFunction>of(),
-              /*packagePath=*/null).evaluateQuery(query, targets);
+              /*packagePath=*/null).evaluateQuery(query);
     } catch (SkyframeRestartQueryException e) {
       // Do not emit errors for skyframe restarts. They make output of the ConfiguredTargetFunction
       // inconsistent from run to run, and make detecting legitimate errors more difficult.
@@ -312,8 +310,7 @@ public class GenQuery implements RuleConfiguredTargetFactory {
     PrintStream printStream = new PrintStream(outputStream);
 
     try {
-      QueryOutputUtils
-          .output(queryOptions, queryResult, targets.getResult(), formatter, printStream,
+      QueryOutputUtils.output(queryOptions, queryResult, formatter, printStream,
           queryOptions.aspectDeps.createResolver(packageProvider, getEventHandler(ruleContext)));
     } catch (ClosedByInterruptException e) {
       throw new InterruptedException(e.getMessage());
diff --git a/src/main/java/com/google/devtools/build/lib/runtime/commands/QueryCommand.java b/src/main/java/com/google/devtools/build/lib/runtime/commands/QueryCommand.java
index b80be41938..2f371c9dd1 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/commands/QueryCommand.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/commands/QueryCommand.java
@@ -16,21 +16,17 @@ package com.google.devtools.build.lib.runtime.commands;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.Constants;
-import com.google.devtools.build.lib.collect.CompactHashSet;
 import com.google.devtools.build.lib.events.Event;
 import com.google.devtools.build.lib.packages.Target;
 import com.google.devtools.build.lib.pkgcache.PackageCacheOptions;
 import com.google.devtools.build.lib.query2.AbstractBlazeQueryEnvironment;
-import com.google.devtools.build.lib.query2.engine.OutputFormatterCallback;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryFunction;
 import com.google.devtools.build.lib.query2.engine.QueryEnvironment.Setting;
 import com.google.devtools.build.lib.query2.engine.QueryEvalResult;
 import com.google.devtools.build.lib.query2.engine.QueryException;
 import com.google.devtools.build.lib.query2.engine.QueryExpression;
 import com.google.devtools.build.lib.query2.output.OutputFormatter;
-import com.google.devtools.build.lib.query2.output.OutputFormatter.StreamedFormatter;
 import com.google.devtools.build.lib.query2.output.QueryOptions;
 import com.google.devtools.build.lib.query2.output.QueryOutputUtils;
 import com.google.devtools.build.lib.runtime.BlazeCommand;
@@ -111,11 +107,10 @@ public final class QueryCommand implements BlazeCommand {
     String query = Joiner.on(' ').join(options.getResidue());
 
     Set<Setting> settings = queryOptions.toSettings();
-    boolean streamResults = QueryOutputUtils.shouldStreamResults(queryOptions, formatter);
     AbstractBlazeQueryEnvironment<Target> queryEnv = newQueryEnvironment(
         env,
         queryOptions.keepGoing,
-        !streamResults,
+        QueryOutputUtils.orderResults(queryOptions, formatter),
         queryOptions.universeScope, queryOptions.loadingPhaseThreads,
         settings);
 
@@ -129,70 +124,36 @@ public final class QueryCommand implements BlazeCommand {
       return ExitCode.COMMAND_LINE_ERROR;
     }
 
-    QueryEvalResult result;
-    PrintStream output = new PrintStream(env.getReporter().getOutErr().getOutputStream());
-    OutputFormatterCallback<Target> callback;
-    if (streamResults) {
-      // 2. Evaluate expression:
-      callback = ((StreamedFormatter) formatter)
-          .createStreamCallback(queryOptions, output, queryOptions.aspectDeps.createResolver(
-              env.getPackageManager(), env.getReporter()));
-    } else {
-      callback = new AggregateAllOutputFormatterCallback<>();
-    }
+    // 2. Evaluate expression:
+    QueryEvalResult<Target> result;
     try {
-      callback.start();
-      result = queryEnv.evaluateQuery(expr, callback);
-    } catch (QueryException e) {
+      result = queryEnv.evaluateQuery(expr);
+    } catch (QueryException | InterruptedException e) {
       // Keep consistent with reportBuildFileError()
       env.getReporter()
-         // TODO(bazel-team): this is a kludge to fix a bug observed in the wild. We should make
-         // sure no null error messages ever get in.
-         .handle(Event.error(e.getMessage() == null ? e.toString() : e.getMessage()));
+          // TODO(bazel-team): this is a kludge to fix a bug observed in the wild. We should make
+          // sure no null error messages ever get in.
+          .handle(Event.error(e.getMessage() == null ? e.toString() : e.getMessage()));
       return ExitCode.ANALYSIS_FAILURE;
-    } catch (InterruptedException e) {
-      IOException ioException = callback.getIoException();
-      if (ioException == null || ioException instanceof ClosedByInterruptException) {
-        env.getReporter().handle(Event.error("query interrupted"));
-        return ExitCode.INTERRUPTED;
-      } else {
-        env.getReporter().handle(Event.error("I/O error: " + e.getMessage()));
-        return ExitCode.LOCAL_ENVIRONMENTAL_ERROR;
-      }
+    }
+
+    env.getReporter().switchToAnsiAllowingHandler();
+    // 3. Output results:
+    PrintStream output = new PrintStream(env.getReporter().getOutErr().getOutputStream());
+    try {
+      QueryOutputUtils.output(queryOptions, result, formatter, output,
+          queryOptions.aspectDeps.createResolver(
+              env.getPackageManager(), env.getReporter()));
+    } catch (ClosedByInterruptException | InterruptedException e) {
+      env.getReporter().handle(Event.error("query interrupted"));
+      return ExitCode.INTERRUPTED;
     } catch (IOException e) {
       env.getReporter().handle(Event.error("I/O error: " + e.getMessage()));
       return ExitCode.LOCAL_ENVIRONMENTAL_ERROR;
     } finally {
       output.flush();
-      try {
-        callback.close();
-      } catch (IOException e) {
-        env.getReporter().handle(Event.error("I/O error: " + e.getMessage()));
-        return ExitCode.LOCAL_ENVIRONMENTAL_ERROR;
-      }
-    }
-    if (!streamResults) {
-      // 3. Output results:
-      try {
-        Set<Target> targets = ((AggregateAllOutputFormatterCallback<Target>) callback).getOutput();
-        QueryOutputUtils.output(queryOptions, result,
-            targets, formatter, output,
-            queryOptions.aspectDeps.createResolver(
-                env.getPackageManager(), env.getReporter()));
-      } catch (ClosedByInterruptException | InterruptedException e) {
-        env.getReporter().handle(Event.error("query interrupted"));
-        return ExitCode.INTERRUPTED;
-      } catch (IOException e) {
-        env.getReporter().handle(Event.error("I/O error: " + e.getMessage()));
-        return ExitCode.LOCAL_ENVIRONMENTAL_ERROR;
-      } finally {
-        output.flush();
-      }
-
     }
-    env.getReporter().switchToAnsiAllowingHandler();
-
-    if (result.isEmpty()) {
+    if (result.getResultSet().isEmpty()) {
       env.getReporter().handle(Event.info("Empty results"));
     }
 
@@ -224,19 +185,4 @@ public final class QueryCommand implements BlazeCommand {
         functions.build(),
         env.getPackageManager().getPackagePath());
   }
-
-  private static class AggregateAllOutputFormatterCallback<T> extends OutputFormatterCallback<T> {
-
-    private Set<T> output = CompactHashSet.create();
-
-    @Override
-    protected final void processOutput(Iterable<T> partialResult)
-        throws IOException, InterruptedException {
-      Iterables.addAll(output, partialResult);
-    }
-
-    public Set<T> getOutput() {
-      return output;
-    }
-  }
 }