Initial (partial) implementation of configured target query. Activated by passing the --post_build_query flag to a build command, with a query expression as the argument. Bazel then executes this query on the configured target graph as constructed by the build command.

Since the prepare graph -> query workflow is how SkyQueryEnvironment works, this is mostly just copying that.

Main missing features/code cleanups:
* Recursive target patterns (/...) are not supported.
* There is no way to specify the configuration of the targets in your query.
* Configuration output is totally opaque (just the hash, or null if no configuration).
* More generally, no output options.
* Some features (visibility, label attrs) not supported.
* No edge filtering (host deps, implicit deps).
* Aspects are totally ignored.
* Graceful failure on errors, edge cases, incompatible flags (like the TAP flags that discard edges).
* Code hygiene issues (calling test-only method to get to Skyframe graph, some code duplication across ConfiguredTargetQueryEnvironment and SkyQueryEnvironment).

Most of the features I plan to leave to rules-side people, since I think they won't be too hard for a general Blaze developer to implement, and designing the right features and user interfaces for these things is better left to the rules side.

PiperOrigin-RevId: 165747829

1 files changed, 64 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutorWrappingWalkableGraph.java b/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutorWrappingWalkableGraph.java
new file mode 100644
index 0000000000..42029c15d9
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutorWrappingWalkableGraph.java
@@ -0,0 +1,64 @@
+// Copyright 2017 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.skyframe;
+
+import com.google.devtools.build.skyframe.DelegatingWalkableGraph;
+import com.google.devtools.build.skyframe.MemoizingEvaluator;
+import com.google.devtools.build.skyframe.NodeEntry;
+import com.google.devtools.build.skyframe.QueryableGraph;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.WalkableGraph;
+import java.util.HashMap;
+import java.util.Map;
+import javax.annotation.Nullable;
+
+/** {@link WalkableGraph} backed by a {@link SkyframeExecutor}. */
+public class SkyframeExecutorWrappingWalkableGraph extends DelegatingWalkableGraph {
+
+  public SkyframeExecutorWrappingWalkableGraph(MemoizingEvaluator evaluator) {
+    super(
+        new QueryableGraph() {
+          @Nullable
+          @Override
+          public NodeEntry get(@Nullable SkyKey requestor, Reason reason, SkyKey key)
+              throws InterruptedException {
+            return evaluator.getGraphMap().get(key);
+          }
+
+          @Override
+          public Map<SkyKey, ? extends NodeEntry> getBatch(
+              @Nullable SkyKey requestor, Reason reason, Iterable<? extends SkyKey> keys)
+              throws InterruptedException {
+            Map<SkyKey, NodeEntry> result = new HashMap<>();
+            for (SkyKey key : keys) {
+              NodeEntry nodeEntry = get(requestor, reason, key);
+              if (nodeEntry != null) {
+                result.put(key, nodeEntry);
+              }
+            }
+            return result;
+          }
+
+          @Override
+          public Iterable<SkyKey> getCurrentlyAvailableNodes(Iterable<SkyKey> keys, Reason reason) {
+            return keys;
+          }
+        });
+  }
+
+  public static SkyframeExecutorWrappingWalkableGraph of(SkyframeExecutor skyframeExecutor) {
+    // TODO(janakr): Provide the graph in a more principled way.
+    return new SkyframeExecutorWrappingWalkableGraph(skyframeExecutor.getEvaluatorForTesting());
+  }
+}