// Copyright 2014 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.analysis;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.devtools.build.lib.packages.RuleClass.Builder.RuleClassType.ABSTRACT;
import static com.google.devtools.build.lib.packages.RuleClass.Builder.RuleClassType.TEST;
import static java.nio.charset.StandardCharsets.UTF_8;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.io.ByteStreams;
import com.google.devtools.build.lib.actions.ActionEnvironment;
import com.google.devtools.build.lib.analysis.RuleContext.PrerequisiteValidator;
import com.google.devtools.build.lib.analysis.buildinfo.BuildInfoFactory;
import com.google.devtools.build.lib.analysis.buildinfo.BuildInfoKey;
import com.google.devtools.build.lib.analysis.config.BuildConfigurationValue;
import com.google.devtools.build.lib.analysis.config.BuildOptions;
import com.google.devtools.build.lib.analysis.config.Fragment;
import com.google.devtools.build.lib.analysis.config.FragmentClassSet;
import com.google.devtools.build.lib.analysis.config.FragmentOptions;
import com.google.devtools.build.lib.analysis.config.FragmentRegistry;
import com.google.devtools.build.lib.analysis.config.SymlinkDefinition;
import com.google.devtools.build.lib.analysis.config.transitions.ComposingTransitionFactory;
import com.google.devtools.build.lib.analysis.config.transitions.PatchTransition;
import com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory;
import com.google.devtools.build.lib.analysis.constraints.ConstraintSemantics;
import com.google.devtools.build.lib.analysis.constraints.RuleContextConstraintSemantics;
import com.google.devtools.build.lib.analysis.starlark.StarlarkGlobalsImpl;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.cmdline.LabelSyntaxException;
import com.google.devtools.build.lib.cmdline.RepositoryName;
import com.google.devtools.build.lib.graph.Digraph;
import com.google.devtools.build.lib.graph.Node;
import com.google.devtools.build.lib.packages.BazelStarlarkEnvironment;
import com.google.devtools.build.lib.packages.NativeAspectClass;
import com.google.devtools.build.lib.packages.RuleClass;
import com.google.devtools.build.lib.packages.RuleClassProvider;
import com.google.devtools.build.lib.packages.RuleFactory;
import com.google.devtools.build.lib.packages.RuleTransitionData;
import com.google.devtools.build.lib.packages.WorkspaceFactory;
import com.google.devtools.build.lib.starlarkbuildapi.core.Bootstrap;
import com.google.devtools.build.lib.vfs.DigestHashFunction;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.lib.vfs.Root;
import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
import com.google.devtools.common.options.OptionDefinition;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Constructor;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.TreeSet;
import java.util.function.Function;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import javax.annotation.Nullable;
import net.starlark.java.annot.StarlarkAnnotations;
import net.starlark.java.annot.StarlarkBuiltin;

/**
 * Knows about every rule Blaze supports and the associated configuration options.
 *
 * <p>This class is initialized on server startup and the set of rules, build info factories and
 * configuration options is guaranteed not to change over the life time of the Blaze server.
 */
// This class has no subclasses except those created by the evil that is mockery.
public /*final*/ class ConfiguredRuleClassProvider
    implements RuleClassProvider, BuildConfigurationValue.GlobalStateProvider {

  /**
   * A coherent set of options, fragments, aspects and rules; each of these may declare a dependency
   * on other such sets.
   */
  public interface RuleSet {
    /** Add stuff to the configured rule class provider builder. */
    void init(ConfiguredRuleClassProvider.Builder builder);

    /** List of required modules. */
    default ImmutableList<RuleSet> requires() {
      return ImmutableList.of();
    }
  }

  /** An InMemoryFileSystem for bundled builtins .bzl files. */
  public static class BundledFileSystem extends InMemoryFileSystem {
    public BundledFileSystem() {
      super(DigestHashFunction.SHA256);
    }

    // Pretend the digest of a bundled file is uniquely determined by its name, not its contents.
    //
    // The contents bundled files are guaranteed to not change throughout the lifetime of the Bazel
    // server, we do not need to detect changes to a bundled file's contents. Not needing to worry
    // about get the actual digest and detect changes to that digest helps avoid peculiarities in
    // the interaction of InMemoryFileSystem and Skyframe. See cl/354809138 for further discussion,
    // including of possible (but unlikely) future caveats of this approach.
    //
    // On the other hand, we do need to want different bundled files to have different digests. That
    // way the bzl environment hashes for bzl rule classes defined in two different bundled files
    // are guaranteed to be different, even if their set of transitive load statements is the same.
    // This is important because it's possible for bzl rule classes defined in different files to
    // have the same name string, and various part of Blaze rely on the pair of
    // "rule class name string" and "bzl environment hash" to uniquely identify a bzl rule class.
    // See b/226379109 for details.

    @Override
    protected synchronized byte[] getFastDigest(PathFragment path) {
      return getDigest(path);
    }

    @Override
    protected synchronized byte[] getDigest(PathFragment path) {
      return getDigestFunction().getHashFunction().hashString(path.toString(), UTF_8).asBytes();
    }
  }

  /** Builder for {@link ConfiguredRuleClassProvider}. */
  public static final class Builder implements RuleDefinitionEnvironment {
    private final StringBuilder defaultWorkspaceFilePrefix = new StringBuilder();
    private final StringBuilder defaultWorkspaceFileSuffix = new StringBuilder();
    private Label preludeLabel;
    private String runfilesPrefix;
    private RepositoryName toolsRepository;
    @Nullable private String builtinsBzlZipResource;
    private boolean useDummyBuiltinsBzlInsteadOfResource = false;
    @Nullable private String builtinsBzlPackagePathInSource;
    private final List<Class<? extends Fragment>> configurationFragmentClasses = new ArrayList<>();
    private final List<BuildInfoFactory> buildInfoFactories = new ArrayList<>();
    private final List<Class<? extends FragmentOptions>> configurationOptions = new ArrayList<>();

    private final Map<String, RuleClass> ruleClassMap = new HashMap<>();
    private final Map<String, RuleDefinition> ruleDefinitionMap = new HashMap<>();
    private final Map<String, NativeAspectClass> nativeAspectClassMap = new HashMap<>();
    private final Map<Class<? extends RuleDefinition>, RuleClass> ruleMap = new HashMap<>();
    private final Digraph<Class<? extends RuleDefinition>> dependencyGraph = new Digraph<>();
    private final List<Class<? extends Fragment>> universalFragments = new ArrayList<>();
    @Nullable private TransitionFactory<RuleTransitionData> trimmingTransitionFactory = null;
    @Nullable private PatchTransition toolchainTaggedTrimmingTransition = null;
    private OptionsDiffPredicate shouldInvalidateCacheForOptionDiff =
        OptionsDiffPredicate.ALWAYS_INVALIDATE;
    private PrerequisiteValidator prerequisiteValidator;
    private final ImmutableMap.Builder<String, Object> buildFileToplevels = ImmutableMap.builder();
    private final ImmutableList.Builder<Bootstrap> starlarkBootstraps = ImmutableList.builder();
    private final ImmutableMap.Builder<String, Object> starlarkAccessibleTopLevels =
        ImmutableMap.builder();
    private final ImmutableMap.Builder<String, Object> starlarkBuiltinsInternals =
        ImmutableMap.builder();
    private final ImmutableList.Builder<SymlinkDefinition> symlinkDefinitions =
        ImmutableList.builder();
    private final Set<String> reservedActionMnemonics = new TreeSet<>();
    private Function<BuildOptions, ActionEnvironment> actionEnvironmentProvider =
        (BuildOptions options) -> ActionEnvironment.EMPTY;
    private ConstraintSemantics<RuleContext> constraintSemantics =
        new RuleContextConstraintSemantics();

    // TODO(b/192694287): Remove once we migrate all tests from the allowlist
    @Nullable private Label networkAllowlistForTests;

    @CanIgnoreReturnValue
    public Builder addWorkspaceFilePrefix(String contents) {
      defaultWorkspaceFilePrefix.append(contents);
      return this;
    }

    @CanIgnoreReturnValue
    @VisibleForTesting
    public Builder clearWorkspaceFilePrefixForTesting() {
      defaultWorkspaceFilePrefix.delete(0, defaultWorkspaceFilePrefix.length());
      return this;
    }

    @CanIgnoreReturnValue
    public Builder addWorkspaceFileSuffix(String contents) {
      defaultWorkspaceFileSuffix.append(contents);
      return this;
    }

    @CanIgnoreReturnValue
    @VisibleForTesting
    public Builder clearWorkspaceFileSuffixForTesting() {
      defaultWorkspaceFileSuffix.delete(0, defaultWorkspaceFileSuffix.length());
      return this;
    }

    @CanIgnoreReturnValue
    public Builder setPrelude(String preludeLabelString) {
      Preconditions.checkArgument(
          preludeLabelString.startsWith("//"),
          "Prelude label '%s' must start with '//'",
          preludeLabelString);
      try {
        // We're parsing this label as if it's in the main repository but it will actually get
        // massaged into a label in the repository where the package being loaded resides.
        this.preludeLabel = Label.parseCanonical(preludeLabelString);
      } catch (LabelSyntaxException e) {
        String errorMsg =
            String.format("Prelude label '%s' is invalid: %s", preludeLabelString, e.getMessage());
        throw new IllegalArgumentException(errorMsg);
      }
      return this;
    }

    @CanIgnoreReturnValue
    public Builder setRunfilesPrefix(String runfilesPrefix) {
      this.runfilesPrefix = runfilesPrefix;
      return this;
    }

    @CanIgnoreReturnValue
    public Builder setToolsRepository(RepositoryName toolsRepository) {
      this.toolsRepository = toolsRepository;
      return this;
    }

    /**
     * Sets the resource path to the builtins_bzl.zip resource.
     *
     * <p>This value is required for production uses. For uses in tests, this may be left null, but
     * the resulting rule class provider will not work with {@code
     * --experimental_builtins_bzl_path=%bundled%}. Alternatively, tests may call {@link
     * #useDummyBuiltinsBzl} if they do not rely on any native rules that may be migratable to
     * Starlark.
     */
    @CanIgnoreReturnValue
    public Builder setBuiltinsBzlZipResource(String name) {
      this.builtinsBzlZipResource = name;
      this.useDummyBuiltinsBzlInsteadOfResource = false;
      return this;
    }

    /**
     * Instructs the rule class provider to use a set of dummy builtins definitions that inject no
     * symbols.
     *
     * <p>This is only suitable for use in tests, and only when the test does not depend (even
     * implicitly) on native rules. For example, pure tests of package loading behavior may call
     * this method, but not tests that use AnalysisMock. Otherwise the test may break when a native
     * rule is migrated to Starlark via builtins injection.
     */
    @CanIgnoreReturnValue
    public Builder useDummyBuiltinsBzl() {
      this.builtinsBzlZipResource = null;
      this.useDummyBuiltinsBzlInsteadOfResource = true;
      return this;
    }

    /**
     * Sets the relative location of the builtins_bzl directory within a Bazel source tree.
     *
     * <p>This is required if the rule class provider will be used with {@code
     * --experimental_builtins_bzl_path=%workspace%}, but can be skipped in unit tests.
     */
    @CanIgnoreReturnValue
    public Builder setBuiltinsBzlPackagePathInSource(String path) {
      this.builtinsBzlPackagePathInSource = path;
      return this;
    }

    @CanIgnoreReturnValue
    public Builder setPrerequisiteValidator(PrerequisiteValidator prerequisiteValidator) {
      this.prerequisiteValidator = prerequisiteValidator;
      return this;
    }

    @CanIgnoreReturnValue
    public Builder addBuildInfoFactory(BuildInfoFactory factory) {
      buildInfoFactories.add(factory);
      return this;
    }

    @CanIgnoreReturnValue
    public Builder addRuleDefinition(RuleDefinition ruleDefinition) {
      Class<? extends RuleDefinition> ruleDefinitionClass = ruleDefinition.getClass();
      ruleDefinitionMap.put(ruleDefinitionClass.getName(), ruleDefinition);
      dependencyGraph.createNode(ruleDefinitionClass);
      for (Class<? extends RuleDefinition> ancestor : ruleDefinition.getMetadata().ancestors()) {
        dependencyGraph.addEdge(ancestor, ruleDefinitionClass);
      }

      return this;
    }

    @CanIgnoreReturnValue
    public Builder addNativeAspectClass(NativeAspectClass aspectFactoryClass) {
      nativeAspectClassMap.put(aspectFactoryClass.getName(), aspectFactoryClass);
      return this;
    }

    /**
     * Adds a configuration fragment and all build options required by its fragment.
     *
     * <p>Note that configuration fragments annotated with a Starlark name must have a unique name;
     * no two different configuration fragments can share the same name.
     */
    @CanIgnoreReturnValue
    public Builder addConfigurationFragment(Class<? extends Fragment> fragmentClass) {
      configurationFragmentClasses.add(fragmentClass);
      return this;
    }

    /**
     * Adds configuration options that aren't required by configuration fragments.
     *
     * <p>If {@link #addConfigurationFragment} adds a fragment that also requires these options,
     * this method is redundant.
     */
    @CanIgnoreReturnValue
    public Builder addConfigurationOptions(Class<? extends FragmentOptions> configurationOptions) {
      this.configurationOptions.add(configurationOptions);
      return this;
    }

    @CanIgnoreReturnValue
    public Builder addUniversalConfigurationFragment(Class<? extends Fragment> fragment) {
      this.universalFragments.add(fragment);
      addConfigurationFragment(fragment);
      return this;
    }

    /**
     * Registers a new top-level symbol for BUILD files.
     *
     * <p>The symbol will also be available in BUILD-loaded .bzl files under the {@code native}
     * module.
     */
    @CanIgnoreReturnValue
    public Builder addBuildFileToplevel(String name, Object object) {
      this.buildFileToplevels.put(name, object);
      return this;
    }

    /**
     * Registers all symbols contained in the {@code Bootstrap} as top-level symbols for .bzl files.
     */
    @CanIgnoreReturnValue
    public Builder addStarlarkBootstrap(Bootstrap bootstrap) {
      this.starlarkBootstraps.add(bootstrap);
      return this;
    }

    /** Registers a new top-level symbol for .bzl files. */
    @CanIgnoreReturnValue
    public Builder addBzlToplevel(String name, Object object) {
      this.starlarkAccessibleTopLevels.put(name, object);
      return this;
    }

    /**
     * Registers a new symbol for {@code @_builtins} .bzl files, to be made available under the
     * {@code _builtins.internal} object.
     */
    @CanIgnoreReturnValue
    public Builder addStarlarkBuiltinsInternal(String name, Object object) {
      this.starlarkBuiltinsInternals.put(name, object);
      return this;
    }

    @CanIgnoreReturnValue
    public Builder addSymlinkDefinition(SymlinkDefinition symlinkDefinition) {
      this.symlinkDefinitions.add(symlinkDefinition);
      return this;
    }

    @CanIgnoreReturnValue
    public Builder addReservedActionMnemonic(String mnemonic) {
      this.reservedActionMnemonics.add(mnemonic);
      return this;
    }

    @CanIgnoreReturnValue
    public Builder setActionEnvironmentProvider(
        Function<BuildOptions, ActionEnvironment> actionEnvironmentProvider) {
      this.actionEnvironmentProvider = actionEnvironmentProvider;
      return this;
    }

    /**
     * Sets the logic that lets rules declare which environments they support and validates rules
     * don't depend on rules that aren't compatible with the same environments. Defaults to {@link
     * ConstraintSemantics}. See {@link ConstraintSemantics} for more details.
     */
    @CanIgnoreReturnValue
    public Builder setConstraintSemantics(ConstraintSemantics<RuleContext> constraintSemantics) {
      this.constraintSemantics = constraintSemantics;
      return this;
    }

    /**
     * Adds a transition factory that produces a trimming transition to be run over all targets
     * after other transitions.
     *
     * <p>Transitions are run in the order they're added.
     *
     * <p>This is a temporary measure for supporting trimming of test rules and manual trimming of
     * feature flags, and support for this transition factory will likely be removed at some point
     * in the future (whenever automatic trimming is sufficiently workable).
     */
    @CanIgnoreReturnValue
    public Builder addTrimmingTransitionFactory(TransitionFactory<RuleTransitionData> factory) {
      Preconditions.checkNotNull(factory);
      Preconditions.checkArgument(!factory.isSplit());
      if (trimmingTransitionFactory == null) {
        trimmingTransitionFactory = factory;
      } else {
        trimmingTransitionFactory =
            ComposingTransitionFactory.of(trimmingTransitionFactory, factory);
      }
      return this;
    }

    /** Sets the transition manual feature flag trimming should apply to toolchain deps. */
    @CanIgnoreReturnValue
    public Builder setToolchainTaggedTrimmingTransition(PatchTransition transition) {
      Preconditions.checkNotNull(transition);
      Preconditions.checkState(toolchainTaggedTrimmingTransition == null);
      this.toolchainTaggedTrimmingTransition = transition;
      return this;
    }

    /**
     * Overrides the transition factory run over all targets.
     *
     * @see #addTrimmingTransitionFactory(TransitionFactory)
     */
    @VisibleForTesting(/* for testing trimming transition factories without relying on prod use */ )
    public Builder overrideTrimmingTransitionFactoryForTesting(
        TransitionFactory<RuleTransitionData> factory) {
      trimmingTransitionFactory = null;
      return this.addTrimmingTransitionFactory(factory);
    }

    /**
     * Sets the predicate which determines whether the analysis cache should be invalidated for the
     * given options diff.
     */
    @CanIgnoreReturnValue
    public Builder setShouldInvalidateCacheForOptionDiff(
        OptionsDiffPredicate shouldInvalidateCacheForOptionDiff) {
      Preconditions.checkState(
          this.shouldInvalidateCacheForOptionDiff.equals(OptionsDiffPredicate.ALWAYS_INVALIDATE),
          "Cache invalidation function was already set");
      this.shouldInvalidateCacheForOptionDiff = shouldInvalidateCacheForOptionDiff;
      return this;
    }

    /**
     * Overrides the predicate which determines whether the analysis cache should be invalidated for
     * the given options diff.
     */
    @VisibleForTesting(/* for testing cache invalidation without relying on prod use */ )
    Builder overrideShouldInvalidateCacheForOptionDiffForTesting(
        OptionsDiffPredicate shouldInvalidateCacheForOptionDiff) {
      this.shouldInvalidateCacheForOptionDiff = OptionsDiffPredicate.ALWAYS_INVALIDATE;
      return this.setShouldInvalidateCacheForOptionDiff(shouldInvalidateCacheForOptionDiff);
    }

    private static RuleConfiguredTargetFactory createFactory(
        Class<? extends RuleConfiguredTargetFactory> factoryClass) {
      try {
        Constructor<? extends RuleConfiguredTargetFactory> ctor = factoryClass.getConstructor();
        return ctor.newInstance();
      } catch (ReflectiveOperationException e) {
        throw new IllegalStateException(e);
      }
    }

    private void commitRuleDefinition(Class<? extends RuleDefinition> definitionClass) {
      RuleDefinition instance =
          checkNotNull(
              ruleDefinitionMap.get(definitionClass.getName()),
              "addRuleDefinition(new %s()) should be called before build()",
              definitionClass.getName());

      RuleDefinition.Metadata metadata = instance.getMetadata();
      checkArgument(
          ruleClassMap.get(metadata.name()) == null,
          "The rule %s was committed already, use another name",
          metadata.name());

      List<Class<? extends RuleDefinition>> ancestors = metadata.ancestors();

      checkArgument(
          metadata.type() == ABSTRACT
              ^ metadata.factoryClass() != RuleConfiguredTargetFactory.class);
      checkArgument(
          (metadata.type() != TEST) || ancestors.contains(BaseRuleClasses.TestBaseRule.class));

      RuleClass[] ancestorClasses = new RuleClass[ancestors.size()];
      for (int i = 0; i < ancestorClasses.length; i++) {
        ancestorClasses[i] = ruleMap.get(ancestors.get(i));
        if (ancestorClasses[i] == null) {
          // Ancestors should have been initialized by now
          throw new IllegalStateException(
              "Ancestor " + ancestors.get(i) + " of " + metadata.name() + " is not initialized");
        }
      }

      RuleConfiguredTargetFactory factory = null;
      if (metadata.type() != ABSTRACT) {
        factory = createFactory(metadata.factoryClass());
      }

      RuleClass.Builder builder =
          new RuleClass.Builder(metadata.name(), metadata.type(), false, ancestorClasses);
      builder.factory(factory);
      RuleClass ruleClass = instance.build(builder, this);
      ruleMap.put(definitionClass, ruleClass);
      ruleClassMap.put(ruleClass.getName(), ruleClass);
      ruleDefinitionMap.put(ruleClass.getName(), instance);
    }

    /**
     * Locates the builtins zip file as a Java resource, and unpacks it into the given directory.
     * Note that the builtins_bzl/ entry itself in the zip is not copied, just its children.
     */
    private static void unpackBuiltinsBzlZipResource(String builtinsResourceName, Path targetRoot) {
      ClassLoader loader = ConfiguredRuleClassProvider.class.getClassLoader();
      try (InputStream builtinsZip = loader.getResourceAsStream(builtinsResourceName)) {
        Preconditions.checkArgument(
            builtinsZip != null, "No resource with name %s", builtinsResourceName);

        try (ZipInputStream zip = new ZipInputStream(builtinsZip)) {
          for (ZipEntry entry = zip.getNextEntry(); entry != null; entry = zip.getNextEntry()) {
            String entryName = entry.getName();
            Preconditions.checkArgument(entryName.startsWith("builtins_bzl/"));
            Path dest = targetRoot.getRelative(entryName.substring("builtins_bzl/".length()));

            dest.getParentDirectory().createDirectoryAndParents();
            try (OutputStream os = dest.getOutputStream()) {
              ByteStreams.copy(zip, os);
            }
          }
        }
      } catch (IOException ex) {
        throw new IllegalArgumentException(
            "Error while unpacking builtins_bzl zip resource file", ex);
      }
    }

    public ConfiguredRuleClassProvider build() {
      for (Node<Class<? extends RuleDefinition>> ruleDefinition :
          dependencyGraph.getTopologicalOrder()) {
        commitRuleDefinition(ruleDefinition.getLabel());
      }

      // Determine the bundled builtins root, if it exists.
      Root builtinsRoot;
      if (builtinsBzlZipResource == null && !useDummyBuiltinsBzlInsteadOfResource) {
        // Use of --experimental_builtins_bzl_path=%bundled% is disallowed.
        builtinsRoot = null;
      } else {
        BundledFileSystem fs = new BundledFileSystem();
        Path builtinsPath = fs.getPath("/virtual_builtins_bzl");
        if (builtinsBzlZipResource != null) {
          // Production case.
          unpackBuiltinsBzlZipResource(builtinsBzlZipResource, builtinsPath);
        } else {
          // Dummy case, use empty bundled builtins content.
          try {
            builtinsPath.createDirectoryAndParents();
            try (OutputStream os = builtinsPath.getRelative("exports.bzl").getOutputStream()) {
              String emptyExports =
                  ("exported_rules = {}\n" //
                      + "exported_toplevels = {}\n"
                      + "exported_to_java = {}\n");
              os.write(emptyExports.getBytes(UTF_8));
            }
          } catch (IOException ex) {
            throw new IllegalStateException("Failed to write dummy builtins root", ex);
          }
        }
        builtinsRoot = Root.fromPath(builtinsPath);
      }

      return new ConfiguredRuleClassProvider(
          preludeLabel,
          runfilesPrefix,
          toolsRepository,
          builtinsRoot,
          builtinsBzlPackagePathInSource,
          ImmutableMap.copyOf(ruleClassMap),
          ImmutableMap.copyOf(ruleDefinitionMap),
          ImmutableMap.copyOf(nativeAspectClassMap),
          FragmentRegistry.create(
              configurationFragmentClasses, universalFragments, configurationOptions),
          defaultWorkspaceFilePrefix.toString(),
          defaultWorkspaceFileSuffix.toString(),
          ImmutableList.copyOf(buildInfoFactories),
          trimmingTransitionFactory,
          toolchainTaggedTrimmingTransition,
          shouldInvalidateCacheForOptionDiff,
          prerequisiteValidator,
          buildFileToplevels.buildOrThrow(),
          starlarkAccessibleTopLevels.buildOrThrow(),
          starlarkBuiltinsInternals.buildOrThrow(),
          starlarkBootstraps.build(),
          symlinkDefinitions.build(),
          ImmutableSet.copyOf(reservedActionMnemonics),
          actionEnvironmentProvider,
          constraintSemantics,
          networkAllowlistForTests);
    }

    @Override
    public RepositoryName getToolsRepository() {
      return toolsRepository;
    }

    @Override
    public Optional<Label> getNetworkAllowlistForTests() {
      return Optional.ofNullable(networkAllowlistForTests);
    }

    @CanIgnoreReturnValue
    public Builder setNetworkAllowlistForTests(Label allowlist) {
      networkAllowlistForTests = allowlist;
      return this;
    }
  }

  /** Default content that should be added at the beginning of the WORKSPACE file. */
  private final String defaultWorkspaceFilePrefix;

  /** Default content that should be added at the end of the WORKSPACE file. */
  private final String defaultWorkspaceFileSuffix;

  /** Label for the prelude file. */
  private final Label preludeLabel;

  /** The default runfiles prefix. */
  private final String runfilesPrefix;

  /** The path to the tools repository. */
  private final RepositoryName toolsRepository;

  /**
   * Where the builtins bzl files are located (if not overridden by
   * --experimental_builtins_bzl_path). Note that this lives in a separate InMemoryFileSystem.
   *
   * <p>May be null in tests, in which case --experimental_builtins_bzl_path must point to a
   * builtins root.
   */
  @Nullable private final Root bundledBuiltinsRoot;

  /**
   * The relative location of the builtins_bzl directory within a Bazel source tree.
   *
   * <p>May be null in tests, in which case --experimental_builtins_bzl_path may not be
   * "%workspace%".
   */
  @Nullable private final String builtinsBzlPackagePathInSource;

  /** Maps rule class name to the metaclass instance for that rule. */
  private final ImmutableMap<String, RuleClass> ruleClassMap;

  /** Maps rule class name to the rule definition objects. */
  private final ImmutableMap<String, RuleDefinition> ruleDefinitionMap;

  /** Maps aspect name to the aspect factory meta class. */
  private final ImmutableMap<String, NativeAspectClass> nativeAspectClassMap;

  private final FragmentRegistry fragmentRegistry;

  /** The transition factory used to produce the transition that will trim targets. */
  @Nullable private final TransitionFactory<RuleTransitionData> trimmingTransitionFactory;

  /** The transition to apply to toolchain deps for manual trimming. */
  @Nullable private final PatchTransition toolchainTaggedTrimmingTransition;

  /** The predicate used to determine whether a diff requires the cache to be invalidated. */
  private final OptionsDiffPredicate shouldInvalidateCacheForOptionDiff;

  private final ImmutableList<BuildInfoFactory> buildInfoFactories;

  private final PrerequisiteValidator prerequisiteValidator;

  private final BazelStarlarkEnvironment bazelStarlarkEnvironment;

  private final ImmutableList<SymlinkDefinition> symlinkDefinitions;

  private final ImmutableSet<String> reservedActionMnemonics;

  private final Function<BuildOptions, ActionEnvironment> actionEnvironmentProvider;

  private final ImmutableMap<String, Class<?>> configurationFragmentMap;

  private final ConstraintSemantics<RuleContext> constraintSemantics;

  // TODO(b/192694287): Remove once we migrate all tests from the allowlist
  @Nullable private final Label networkAllowlistForTests;

  private ConfiguredRuleClassProvider(
      Label preludeLabel,
      String runfilesPrefix,
      RepositoryName toolsRepository,
      @Nullable Root bundledBuiltinsRoot,
      @Nullable String builtinsBzlPackagePathInSource,
      ImmutableMap<String, RuleClass> ruleClassMap,
      ImmutableMap<String, RuleDefinition> ruleDefinitionMap,
      ImmutableMap<String, NativeAspectClass> nativeAspectClassMap,
      FragmentRegistry fragmentRegistry,
      String defaultWorkspaceFilePrefix,
      String defaultWorkspaceFileSuffix,
      ImmutableList<BuildInfoFactory> buildInfoFactories,
      @Nullable TransitionFactory<RuleTransitionData> trimmingTransitionFactory,
      PatchTransition toolchainTaggedTrimmingTransition,
      OptionsDiffPredicate shouldInvalidateCacheForOptionDiff,
      PrerequisiteValidator prerequisiteValidator,
      ImmutableMap<String, Object> buildFileToplevels,
      ImmutableMap<String, Object> starlarkAccessibleTopLevels,
      ImmutableMap<String, Object> starlarkBuiltinsInternals,
      ImmutableList<Bootstrap> starlarkBootstraps,
      ImmutableList<SymlinkDefinition> symlinkDefinitions,
      ImmutableSet<String> reservedActionMnemonics,
      Function<BuildOptions, ActionEnvironment> actionEnvironmentProvider,
      ConstraintSemantics<RuleContext> constraintSemantics,
      @Nullable Label networkAllowlistForTests) {
    this.preludeLabel = preludeLabel;
    this.runfilesPrefix = runfilesPrefix;
    this.toolsRepository = toolsRepository;
    this.bundledBuiltinsRoot = bundledBuiltinsRoot;
    this.builtinsBzlPackagePathInSource = builtinsBzlPackagePathInSource;
    this.ruleClassMap = ruleClassMap;
    this.ruleDefinitionMap = ruleDefinitionMap;
    this.nativeAspectClassMap = nativeAspectClassMap;
    this.fragmentRegistry = fragmentRegistry;
    this.defaultWorkspaceFilePrefix = defaultWorkspaceFilePrefix;
    this.defaultWorkspaceFileSuffix = defaultWorkspaceFileSuffix;
    this.buildInfoFactories = buildInfoFactories;
    this.trimmingTransitionFactory = trimmingTransitionFactory;
    this.toolchainTaggedTrimmingTransition = toolchainTaggedTrimmingTransition;
    this.shouldInvalidateCacheForOptionDiff = shouldInvalidateCacheForOptionDiff;
    this.prerequisiteValidator = prerequisiteValidator;
    this.symlinkDefinitions = symlinkDefinitions;
    this.reservedActionMnemonics = reservedActionMnemonics;
    this.actionEnvironmentProvider = actionEnvironmentProvider;
    this.configurationFragmentMap = createFragmentMap(fragmentRegistry.getAllFragments());
    this.constraintSemantics = constraintSemantics;
    this.networkAllowlistForTests = networkAllowlistForTests;

    ImmutableMap<String, Object> registeredBzlToplevels =
        createRegisteredBzlToplevels(starlarkAccessibleTopLevels, starlarkBootstraps);
    // If needed, we could allow the version to be customized by the builder e.g. for unit testing,
    // but at the moment it suffices to use the production value unconditionally.
    String version = BlazeVersionInfo.instance().getVersion();
    this.bazelStarlarkEnvironment =
        new BazelStarlarkEnvironment(
            StarlarkGlobalsImpl.INSTANCE,
            /* ruleFunctions= */ RuleFactory.buildRuleFunctions(ruleClassMap),
            buildFileToplevels,
            registeredBzlToplevels,
            /* workspaceBzlNativeBindings= */ WorkspaceFactory.createNativeModuleBindings(
                ruleClassMap, version),
            /* builtinsInternals= */ starlarkBuiltinsInternals);
  }

  public PrerequisiteValidator getPrerequisiteValidator() {
    return prerequisiteValidator;
  }

  @Override
  public Label getPreludeLabel() {
    return preludeLabel;
  }

  @Override
  public String getRunfilesPrefix() {
    return runfilesPrefix;
  }

  @Override
  public RepositoryName getToolsRepository() {
    return toolsRepository;
  }

  @Override
  @Nullable
  public Root getBundledBuiltinsRoot() {
    return bundledBuiltinsRoot;
  }

  @Override
  @Nullable
  public String getBuiltinsBzlPackagePathInSource() {
    return builtinsBzlPackagePathInSource;
  }

  @Override
  public ImmutableMap<String, RuleClass> getRuleClassMap() {
    return ruleClassMap;
  }

  @Override
  public Map<String, NativeAspectClass> getNativeAspectClassMap() {
    return nativeAspectClassMap;
  }

  @Override
  public NativeAspectClass getNativeAspectClass(String key) {
    return nativeAspectClassMap.get(key);
  }

  @Override
  public FragmentRegistry getFragmentRegistry() {
    return fragmentRegistry;
  }

  public Map<BuildInfoKey, BuildInfoFactory> getBuildInfoFactoriesAsMap() {
    ImmutableMap.Builder<BuildInfoKey, BuildInfoFactory> factoryMapBuilder = ImmutableMap.builder();
    for (BuildInfoFactory factory : buildInfoFactories) {
      factoryMapBuilder.put(factory.getKey(), factory);
    }
    return factoryMapBuilder.buildOrThrow();
  }

  /**
   * Returns the transition factory used to produce the transition to trim targets.
   *
   * <p>This is a temporary measure for supporting manual trimming of feature flags, and support for
   * this transition factory will likely be removed at some point in the future (whenever automatic
   * trimming is sufficiently workable
   */
  @Nullable
  public TransitionFactory<RuleTransitionData> getTrimmingTransitionFactory() {
    return trimmingTransitionFactory;
  }

  /**
   * Returns the transition manual feature flag trimming should apply to toolchain deps.
   *
   * <p>See extra notes on {@link #getTrimmingTransitionFactory()}.
   */
  @Nullable
  public PatchTransition getToolchainTaggedTrimmingTransition() {
    return toolchainTaggedTrimmingTransition;
  }

  /** Returns whether the analysis cache should be invalidated for the given option diff. */
  public boolean shouldInvalidateCacheForOptionDiff(
      BuildOptions newOptions, OptionDefinition changedOption, Object oldValue, Object newValue) {
    return shouldInvalidateCacheForOptionDiff.apply(newOptions, changedOption, oldValue, newValue);
  }

  /** Returns the definition of the rule class definition with the specified name. */
  public RuleDefinition getRuleClassDefinition(String ruleClassName) {
    return ruleDefinitionMap.get(ruleClassName);
  }

  private static ImmutableMap<String, Object> createRegisteredBzlToplevels(
      ImmutableMap<String, Object> starlarkAccessibleTopLevels,
      ImmutableList<Bootstrap> bootstraps) {
    ImmutableMap.Builder<String, Object> bindings = ImmutableMap.builder();
    bindings.putAll(starlarkAccessibleTopLevels);
    for (Bootstrap bootstrap : bootstraps) {
      bootstrap.addBindingsToBuilder(bindings);
    }
    return bindings.buildOrThrow();
  }

  private static ImmutableMap<String, Class<?>> createFragmentMap(
      FragmentClassSet configurationFragments) {
    ImmutableMap.Builder<String, Class<?>> mapBuilder = ImmutableMap.builder();
    for (Class<? extends Fragment> fragmentClass : configurationFragments) {
      StarlarkBuiltin fragmentModule = StarlarkAnnotations.getStarlarkBuiltin(fragmentClass);
      if (fragmentModule != null) {
        mapBuilder.put(fragmentModule.name(), fragmentClass);
      }
    }
    return mapBuilder.buildOrThrow();
  }

  @Override
  public BazelStarlarkEnvironment getBazelStarlarkEnvironment() {
    return bazelStarlarkEnvironment;
  }

  @Override
  public String getDefaultWorkspacePrefix() {
    return defaultWorkspaceFilePrefix;
  }

  @Override
  public String getDefaultWorkspaceSuffix() {
    return defaultWorkspaceFileSuffix;
  }

  @Override
  public ImmutableMap<String, Class<?>> getConfigurationFragmentMap() {
    return configurationFragmentMap;
  }

  /**
   * Returns the symlink definitions introduced by the fragments registered with this rule class
   * provider.
   *
   * <p>This only includes definitions added by {@link Builder#addSymlinkDefinition}, not the
   * standard symlinks in {@link com.google.devtools.build.lib.buildtool.OutputDirectoryLinksUtils}.
   *
   * <p>Note: Usages of custom symlink definitions should be rare. Currently it is only used to
   * implement the py2-bin / py3-bin symlinks.
   */
  public ImmutableList<SymlinkDefinition> getSymlinkDefinitions() {
    return symlinkDefinitions;
  }

  public ConstraintSemantics<RuleContext> getConstraintSemantics() {
    return constraintSemantics;
  }

  @Override
  public Optional<Label> getNetworkAllowlistForTests() {
    return Optional.ofNullable(networkAllowlistForTests);
  }

  /** Returns a reserved set of action mnemonics. These cannot be used from a Starlark action. */
  @Override
  public ImmutableSet<String> getReservedActionMnemonics() {
    return reservedActionMnemonics;
  }

  @Override
  public ActionEnvironment getActionEnvironment(BuildOptions buildOptions) {
    return actionEnvironmentProvider.apply(buildOptions);
  }
}