Implement propagation along dependencies for Skylark aspects.

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MOS_MIGRATED_REVID=106694515

1 files changed, 85 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ToplevelSkylarkAspectFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/ToplevelSkylarkAspectFunction.java
new file mode 100644
index 0000000000..fabb1bb058
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ToplevelSkylarkAspectFunction.java
@@ -0,0 +1,85 @@
+// 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.skyframe;
+
+import com.google.devtools.build.lib.cmdline.PackageIdentifier;
+import com.google.devtools.build.lib.packages.AspectParameters;
+import com.google.devtools.build.lib.rules.SkylarkRuleClassFunctions.SkylarkAspect;
+import com.google.devtools.build.lib.rules.SkylarkRuleClassFunctions.SkylarkAspectClass;
+import com.google.devtools.build.lib.skyframe.ASTFileLookupValue.ASTLookupInputException;
+import com.google.devtools.build.lib.skyframe.AspectValue.SkylarkAspectLoadingKey;
+import com.google.devtools.build.lib.syntax.Type.ConversionException;
+import com.google.devtools.build.skyframe.SkyFunction;
+import com.google.devtools.build.skyframe.SkyFunctionException;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.SkyValue;
+
+import javax.annotation.Nullable;
+
+/**
+ * SkyFunction to load aspects from Skylark extensions and calculate their values.
+ *
+ * Used for loading top-level aspects. At top level, in
+ * {@link com.google.devtools.build.lib.analysis.BuildView}, we cannot invoke two SkyFunctions
+ * one aftre another, so BuildView call this function to do the work.
+ */
+public class ToplevelSkylarkAspectFunction implements SkyFunction {
+
+  @Nullable
+  @Override
+  public SkyValue compute(SkyKey skyKey, Environment env)
+      throws LoadSkylarkAspectFunctionException, InterruptedException {
+    SkylarkAspectLoadingKey aspectLoadingKey = (SkylarkAspectLoadingKey) skyKey.argument();
+    String skylarkValueName = aspectLoadingKey.getSkylarkValueName();
+    PackageIdentifier extensionFile = aspectLoadingKey.getExtensionFile();
+    SkylarkAspect skylarkAspect = null;
+    try {
+      skylarkAspect = AspectFunction.loadSkylarkAspect(env, extensionFile, skylarkValueName);
+    } catch (ASTLookupInputException | ConversionException e) {
+      throw new LoadSkylarkAspectFunctionException(e, skyKey);
+    }
+    if (skylarkAspect == null) {
+      return null;
+    }
+    SkyKey aspectKey =
+        AspectValue.key(
+            aspectLoadingKey.getTargetLabel(),
+            aspectLoadingKey.getTargetConfiguration(),
+            new SkylarkAspectClass(skylarkAspect),
+            AspectParameters.EMPTY);
+
+    return env.getValue(aspectKey);
+  }
+
+  @Nullable
+  @Override
+  public String extractTag(SkyKey skyKey) {
+    return null;
+  }
+
+  /**
+   * Exceptions thrown from ToplevelSkylarkAspectFunction.
+   */
+  public class LoadSkylarkAspectFunctionException extends SkyFunctionException {
+
+    public LoadSkylarkAspectFunctionException(Exception cause, SkyKey childKey) {
+      super(cause, childKey);
+    }
+
+    public LoadSkylarkAspectFunctionException(Exception cause) {
+      super(cause, Transience.PERSISTENT);
+    }
+  }
+}