1 files changed, 146 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ConfigurationFragmentFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/ConfigurationFragmentFunction.java
new file mode 100644
index 0000000000..0393b16aa6
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ConfigurationFragmentFunction.java
@@ -0,0 +1,146 @@
+// Copyright 2014 Google Inc. 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.common.base.Supplier;
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.analysis.BlazeDirectories;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration.Fragment;
+import com.google.devtools.build.lib.analysis.config.BuildOptions;
+import com.google.devtools.build.lib.analysis.config.ConfigurationEnvironment;
+import com.google.devtools.build.lib.analysis.config.ConfigurationFragmentFactory;
+import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
+import com.google.devtools.build.lib.analysis.config.PackageProviderForConfigurations;
+import com.google.devtools.build.lib.packages.NoSuchPackageException;
+import com.google.devtools.build.lib.packages.NoSuchTargetException;
+import com.google.devtools.build.lib.packages.Package;
+import com.google.devtools.build.lib.packages.Target;
+import com.google.devtools.build.lib.skyframe.ConfigurationFragmentValue.ConfigurationFragmentKey;
+import com.google.devtools.build.lib.syntax.Label;
+import com.google.devtools.build.lib.syntax.Label.SyntaxException;
+import com.google.devtools.build.lib.vfs.Path;
+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 java.io.IOException;
+import java.util.Set;
+
+/**
+ * A builder for {@link ConfigurationFragmentValue}s.
+ */
+public class ConfigurationFragmentFunction implements SkyFunction {
+
+  private final Supplier<ImmutableList<ConfigurationFragmentFactory>> configurationFragments;
+  private final Supplier<Set<Package>> configurationPackages;
+
+  public ConfigurationFragmentFunction(
+      Supplier<ImmutableList<ConfigurationFragmentFactory>> configurationFragments,
+      Supplier<Set<Package>> configurationPackages) {
+    this.configurationFragments = configurationFragments;
+    this.configurationPackages = configurationPackages;
+  }
+
+  @Override
+  public SkyValue compute(SkyKey skyKey, Environment env) throws InterruptedException,
+      ConfigurationFragmentFunctionException {
+    ConfigurationFragmentKey configurationFragmentKey = 
+        (ConfigurationFragmentKey) skyKey.argument();
+    BuildOptions buildOptions = configurationFragmentKey.getBuildOptions();
+    ConfigurationFragmentFactory factory = getFactory(configurationFragmentKey.getFragmentType());
+    try {
+      PackageProviderForConfigurations loadedPackageProvider = 
+          new SkyframePackageLoaderWithValueEnvironment(env, configurationPackages.get());
+      ConfigurationEnvironment confEnv = new ConfigurationBuilderEnvironment(loadedPackageProvider);
+      Fragment fragment = factory.create(confEnv, buildOptions);
+      
+      if (env.valuesMissing()) {
+        return null;
+      }
+      return new ConfigurationFragmentValue(fragment);
+    } catch (InvalidConfigurationException e) {
+      // TODO(bazel-team): Rework the control-flow here so that we're not actually throwing this
+      // exception with missing Skyframe dependencies.
+      if (env.valuesMissing()) {
+        return null;
+      }
+      throw new ConfigurationFragmentFunctionException(e);
+    }
+  }
+  
+  private ConfigurationFragmentFactory getFactory(Class<? extends Fragment> fragmentType) {
+    for (ConfigurationFragmentFactory factory : configurationFragments.get()) {
+      if (factory.creates().equals(fragmentType)) {
+        return factory;
+      }
+    }
+    throw new IllegalStateException(
+        "There is no factory for fragment: " + fragmentType.getSimpleName());
+  }
+
+  @Override
+  public String extractTag(SkyKey skyKey) {
+    return null;
+  }
+  
+  /**
+   * A {@link ConfigurationEnvironment} implementation that can create dependencies on files.
+   */
+  private final class ConfigurationBuilderEnvironment implements ConfigurationEnvironment {
+    private final PackageProviderForConfigurations loadedPackageProvider;
+
+    ConfigurationBuilderEnvironment(
+        PackageProviderForConfigurations loadedPackageProvider) {
+      this.loadedPackageProvider = loadedPackageProvider;
+    }
+
+    @Override
+    public Target getTarget(Label label) throws NoSuchPackageException, NoSuchTargetException {
+      return loadedPackageProvider.getLoadedTarget(label);
+    }
+
+    @Override
+    public Path getPath(Package pkg, String fileName) {
+      Path result = pkg.getPackageDirectory().getRelative(fileName);
+      try {
+        loadedPackageProvider.addDependency(pkg, fileName);
+      } catch (IOException | SyntaxException e) {
+        return null;
+      }
+      return result;
+    }
+
+    @Override
+    public <T extends Fragment> T getFragment(BuildOptions buildOptions, Class<T> fragmentType) 
+        throws InvalidConfigurationException {
+      return loadedPackageProvider.getFragment(buildOptions, fragmentType);
+    }
+
+    @Override
+    public BlazeDirectories getBlazeDirectories() {
+      return loadedPackageProvider.getDirectories();
+    }
+  }
+
+  /**
+   * Used to declare all the exception types that can be wrapped in the exception thrown by
+   * {@link ConfigurationFragmentFunction#compute}.
+   */
+  private static final class ConfigurationFragmentFunctionException extends SkyFunctionException {
+    public ConfigurationFragmentFunctionException(InvalidConfigurationException e) {
+      super(e, Transience.PERSISTENT);
+    }
+  }
+}