Use a thin graph when querying reverse deps (or others that don't need the values).

--
MOS_MIGRATED_REVID=105893837

1 files changed, 20 insertions, 9 deletions

diff --git a/src/main/java/com/google/devtools/build/skyframe/DelegatingWalkableGraph.java b/src/main/java/com/google/devtools/build/skyframe/DelegatingWalkableGraph.java
index 1565090442..82cad233fb 100644
--- a/src/main/java/com/google/devtools/build/skyframe/DelegatingWalkableGraph.java
+++ b/src/main/java/com/google/devtools/build/skyframe/DelegatingWalkableGraph.java
@@ -28,19 +28,30 @@ import javax.annotation.Nullable;
  * {@link WalkableGraph} that looks nodes up in a {@link QueryableGraph}.
  */
 public class DelegatingWalkableGraph implements WalkableGraph {
-  private final QueryableGraph graph;
+
+  private final QueryableGraph fullGraph;
+  private final QueryableGraph thinGraph;
 
   public DelegatingWalkableGraph(QueryableGraph graph) {
-    this.graph = graph;
+    this(graph, graph);
+  }
+
+  /**
+   * Use this constructor when you want to differentiate reads that require the node value vs reads
+   * that only traverse dependencies.
+   */
+  public DelegatingWalkableGraph(QueryableGraph fullGraph, QueryableGraph thinGraph) {
+    this.fullGraph = fullGraph;
+    this.thinGraph = thinGraph;
   }
 
   private NodeEntry getEntry(SkyKey key) {
-    NodeEntry entry = Preconditions.checkNotNull(graph.get(key), key);
+    NodeEntry entry = Preconditions.checkNotNull(fullGraph.get(key), key);
     Preconditions.checkState(entry.isDone(), "%s %s", key, entry);
     return entry;
   }
 
-  private Map<SkyKey, NodeEntry> getEntries(Iterable<SkyKey> keys) {
+  private static Map<SkyKey, NodeEntry> getEntries(Iterable<SkyKey> keys, QueryableGraph graph) {
     Map<SkyKey, NodeEntry> result = graph.getBatch(keys);
     Preconditions.checkState(result.size() == Iterables.size(keys), "%s %s", keys, result);
     for (Map.Entry<SkyKey, NodeEntry> entry : result.entrySet()) {
@@ -51,7 +62,7 @@ public class DelegatingWalkableGraph implements WalkableGraph {
 
   @Override
   public boolean exists(SkyKey key) {
-    NodeEntry entry = graph.get(key);
+    NodeEntry entry = thinGraph.get(key);
     return entry != null && entry.isDone();
   }
 
@@ -72,14 +83,14 @@ public class DelegatingWalkableGraph implements WalkableGraph {
 
   @Override
   public Map<SkyKey, SkyValue> getSuccessfulValues(Iterable<SkyKey> keys) {
-    return Maps.filterValues(Maps.transformValues(graph.getBatch(keys), GET_SKY_VALUE_FUNCTION),
+    return Maps.filterValues(Maps.transformValues(fullGraph.getBatch(keys), GET_SKY_VALUE_FUNCTION),
         Predicates.notNull());
   }
 
   @Override
   public Map<SkyKey, Exception> getMissingAndExceptions(Iterable<SkyKey> keys) {
     Map<SkyKey, Exception> result = new HashMap<>();
-    Map<SkyKey, NodeEntry> graphResult = graph.getBatch(keys);
+    Map<SkyKey, NodeEntry> graphResult = fullGraph.getBatch(keys);
     for (SkyKey key : keys) {
       NodeEntry nodeEntry = graphResult.get(key);
       if (nodeEntry == null || !nodeEntry.isDone()) {
@@ -111,7 +122,7 @@ public class DelegatingWalkableGraph implements WalkableGraph {
 
   @Override
   public Map<SkyKey, Iterable<SkyKey>> getDirectDeps(Iterable<SkyKey> keys) {
-    return Maps.transformValues(getEntries(keys), GET_DIRECT_DEPS_FUNCTION);
+    return Maps.transformValues(getEntries(keys, thinGraph), GET_DIRECT_DEPS_FUNCTION);
   }
 
   private static final Function<NodeEntry, Iterable<SkyKey>> GET_REVERSE_DEPS_FUNCTION =
@@ -124,6 +135,6 @@ public class DelegatingWalkableGraph implements WalkableGraph {
 
   @Override
   public Map<SkyKey, Iterable<SkyKey>> getReverseDeps(Iterable<SkyKey> keys) {
-    return Maps.transformValues(getEntries(keys), GET_REVERSE_DEPS_FUNCTION);
+    return Maps.transformValues(getEntries(keys, thinGraph), GET_REVERSE_DEPS_FUNCTION);
   }
 }