Rollback of commit 8e7da87.

*** Reason for rollback ***

--
MOS_MIGRATED_REVID=109005097

src/main/java/com/google/devtools/build/lib/bazel/commands/FetchCommand.java

@@ -22,7 +22,6 @@
 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 ExitCode exec(CommandEnvironment env, OptionsProvider options) {
 
     // 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()));

src/main/java/com/google/devtools/build/lib/query2/AbstractBlazeQueryEnvironment.java

@@ -17,7 +17,6 @@
 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.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.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 static AbstractBlazeQueryEnvironment<Target> newQueryEnvironment(
    * @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 QueryEvalResult evaluateQuery(QueryExpression expr, final Callback<T> cal
         // 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 void process(Iterable<T> partialResult)
       }
     }
 
-    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

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",

src/main/java/com/google/devtools/build/lib/query2/BlazeQueryEnvironment.java

@@ -37,8 +37,8 @@
 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.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

src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java

@@ -167,14 +167,14 @@ private void init() throws InterruptedException {
   }
 
   @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 @@ private static void addIfUniqueLabel(Target node, Set<Label> labels, Set<Target>
     }
   }
 
-  private static Target getSubincludeTarget(Label label, Package pkg) {
+  private static Target getSubincludeTarget(final Label label, Package pkg) {
     return new FakeSubincludeTarget(label, pkg);
   }
 

src/main/java/com/google/devtools/build/lib/query2/engine/DigraphQueryEvalResult.java → src/main/java/com/google/devtools/build/lib/query2/engine/BlazeQueryEvalResult.java

@@ -17,18 +17,20 @@
 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);
   }
 }

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 boolean getSuccess() {
     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();
   }
 }