// 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.rules.objc;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget.Mode.TARGET;
import static com.google.devtools.build.lib.packages.Attribute.attr;
import static com.google.devtools.build.lib.packages.BuildType.LABEL;
import static java.nio.charset.StandardCharsets.ISO_8859_1;

import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.MutableActionGraph.ActionConflictException;
import com.google.devtools.build.lib.actions.ParamFileInfo;
import com.google.devtools.build.lib.actions.ParameterFile;
import com.google.devtools.build.lib.actions.ParameterFile.ParameterFileType;
import com.google.devtools.build.lib.analysis.ConfiguredAspect;
import com.google.devtools.build.lib.analysis.ConfiguredAspectFactory;
import com.google.devtools.build.lib.analysis.ConfiguredTarget;
import com.google.devtools.build.lib.analysis.RuleContext;
import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
import com.google.devtools.build.lib.analysis.actions.CustomCommandLine;
import com.google.devtools.build.lib.analysis.actions.CustomCommandLine.VectorArg;
import com.google.devtools.build.lib.analysis.actions.SpawnAction;
import com.google.devtools.build.lib.analysis.config.ConfigAwareAspectBuilder;
import com.google.devtools.build.lib.analysis.config.HostTransition;
import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget.Mode;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.collect.nestedset.NestedSet;
import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
import com.google.devtools.build.lib.packages.AspectDefinition;
import com.google.devtools.build.lib.packages.AspectParameters;
import com.google.devtools.build.lib.packages.Attribute.LabelLateBoundDefault;
import com.google.devtools.build.lib.packages.Attribute.LateBoundDefault.Resolver;
import com.google.devtools.build.lib.packages.BuildType;
import com.google.devtools.build.lib.packages.NativeAspectClass;
import com.google.devtools.build.lib.packages.RuleClass.ConfiguredTargetFactory.RuleErrorException;
import com.google.devtools.build.lib.packages.SkylarkProviderIdentifier;
import com.google.devtools.build.lib.rules.apple.AppleConfiguration;
import com.google.devtools.build.lib.rules.apple.AppleToolchain;
import com.google.devtools.build.lib.rules.apple.XcodeConfigRule;
import com.google.devtools.build.lib.rules.cpp.CcToolchainProvider;
import com.google.devtools.build.lib.rules.cpp.CppConfiguration;
import com.google.devtools.build.lib.rules.cpp.CppHelper;
import com.google.devtools.build.lib.rules.cpp.CppRuleClasses;
import com.google.devtools.build.lib.rules.java.JavaCommon;
import com.google.devtools.build.lib.rules.java.JavaCompilationArgsProvider;
import com.google.devtools.build.lib.rules.java.JavaConfiguration;
import com.google.devtools.build.lib.rules.java.JavaGenJarsProvider;
import com.google.devtools.build.lib.rules.java.JavaInfo;
import com.google.devtools.build.lib.rules.java.JavaRuntimeInfo;
import com.google.devtools.build.lib.rules.java.JavaSourceInfoProvider;
import com.google.devtools.build.lib.rules.objc.CompilationSupport.ExtraCompileArgs;
import com.google.devtools.build.lib.rules.objc.J2ObjcSource.SourceType;
import com.google.devtools.build.lib.rules.proto.ProtoCommon;
import com.google.devtools.build.lib.rules.proto.ProtoCompileActionBuilder;
import com.google.devtools.build.lib.rules.proto.ProtoCompileActionBuilder.Exports;
import com.google.devtools.build.lib.rules.proto.ProtoCompileActionBuilder.Services;
import com.google.devtools.build.lib.rules.proto.ProtoConfiguration;
import com.google.devtools.build.lib.rules.proto.ProtoInfo;
import com.google.devtools.build.lib.rules.proto.ProtoLangToolchainProvider;
import com.google.devtools.build.lib.rules.proto.ProtoSourceFileBlacklist;
import com.google.devtools.build.lib.skyframe.ConfiguredTargetAndData;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
import com.google.devtools.build.lib.util.FileType;
import com.google.devtools.build.lib.vfs.PathFragment;
import java.io.Serializable;
import java.util.List;
import java.util.stream.Collectors;

/** J2ObjC transpilation aspect for Java and proto rules. */
public class J2ObjcAspect extends NativeAspectClass implements ConfiguredAspectFactory {
  public static final String NAME = "J2ObjcAspect";

  private static final ExtraCompileArgs EXTRA_COMPILE_ARGS = new ExtraCompileArgs(
      "-fno-strict-overflow");

  private static LabelLateBoundDefault<ProtoConfiguration> getProtoToolchainLabel(
      String defaultValue) {
    return LabelLateBoundDefault.fromTargetConfiguration(
        ProtoConfiguration.class,
        Label.parseAbsoluteUnchecked(defaultValue),
        (Resolver<ProtoConfiguration, Label> & Serializable)
            (rule, attributes, protoConfig) -> protoConfig.protoToolchainForJ2objc());
  }

  private static final ImmutableList<Attribute> JAVA_DEPENDENT_ATTRIBUTES =
      ImmutableList.of(
          new Attribute("$jre_lib", Mode.TARGET),
          new Attribute("deps", Mode.TARGET),
          new Attribute("exports", Mode.TARGET),
          new Attribute("runtime_deps", Mode.TARGET));

  private static final ImmutableList<Attribute> PROTO_DEPENDENT_ATTRIBUTES =
      ImmutableList.of(new Attribute("deps", Mode.TARGET));

  private static final String J2OBJC_PROTO_TOOLCHAIN_ATTR = ":j2objc_proto_toolchain";

  @AutoCodec @AutoCodec.VisibleForSerialization
  static final LabelLateBoundDefault<?> DEAD_CODE_REPORT =
      LabelLateBoundDefault.fromTargetConfiguration(
          J2ObjcConfiguration.class,
          null,
          (rule, attributes, j2objcConfig) -> j2objcConfig.deadCodeReport());

  private final String toolsRepository;
  private final Label ccToolchainType;
  private final LabelLateBoundDefault<CppConfiguration> ccToolchain;

  public J2ObjcAspect(RuleDefinitionEnvironment env) {
    this.toolsRepository = checkNotNull(env.getToolsRepository());
    this.ccToolchainType = CppRuleClasses.ccToolchainTypeAttribute(env);
    this.ccToolchain = CppRuleClasses.ccToolchainAttribute(env);
  }

  /** Returns whether this aspect allows proto services to be generated from this proto rule */
  protected boolean shouldAllowProtoServices(RuleContext ruleContext) {
    return true;
  }

  @Override
  public AspectDefinition getDefinition(AspectParameters aspectParameters) {
    return ConfigAwareAspectBuilder.of(new AspectDefinition.Builder(this))
        .requiresHostConfigurationFragments(JavaConfiguration.class)
        .originalBuilder()
        .propagateAlongAttribute("deps")
        .propagateAlongAttribute("exports")
        .propagateAlongAttribute("runtime_deps")
        .requireSkylarkProviders(SkylarkProviderIdentifier.forKey(JavaInfo.PROVIDER.getKey()))
        .requireSkylarkProviders(ProtoInfo.PROVIDER.id())
        .requiresConfigurationFragments(
            AppleConfiguration.class,
            CppConfiguration.class,
            J2ObjcConfiguration.class,
            ObjcConfiguration.class,
            ProtoConfiguration.class)
        .addRequiredToolchains(ccToolchainType)
        .add(
            attr("$grep_includes", LABEL)
                .cfg(HostTransition.createFactory())
                .value(Label.parseAbsoluteUnchecked(toolsRepository + "//tools/cpp:grep-includes")))
        .add(
            attr("$j2objc", LABEL)
                .cfg(HostTransition.createFactory())
                .exec()
                .value(
                    Label.parseAbsoluteUnchecked(
                        toolsRepository + "//tools/j2objc:j2objc_deploy.jar")))
        .add(
            attr("$j2objc_wrapper", LABEL)
                .allowedFileTypes(FileType.of(".py"))
                .cfg(HostTransition.createFactory())
                .exec()
                .singleArtifact()
                .value(
                    Label.parseAbsoluteUnchecked(
                        toolsRepository + "//tools/j2objc:j2objc_wrapper")))
        .add(
            attr("$j2objc_header_map", LABEL)
                .allowedFileTypes(FileType.of(".py"))
                .cfg(HostTransition.createFactory())
                .exec()
                .singleArtifact()
                .value(
                    Label.parseAbsoluteUnchecked(
                        toolsRepository + "//tools/j2objc:j2objc_header_map")))
        .add(
            attr("$jre_emul_jar", LABEL)
                .cfg(HostTransition.createFactory())
                .value(
                    Label.parseAbsoluteUnchecked(
                        toolsRepository + "//third_party/java/j2objc:jre_emul.jar")))
        .add(
            attr("$jre_emul_module", LABEL)
                .cfg(HostTransition.createFactory())
                .value(
                    Label.parseAbsoluteUnchecked(
                        toolsRepository + "//third_party/java/j2objc:jre_emul_module")))
        .add(
            attr(":dead_code_report", LABEL)
                .cfg(HostTransition.createFactory())
                .value(DEAD_CODE_REPORT))
        .add(
            attr("$jre_lib", LABEL)
                .value(
                    Label.parseAbsoluteUnchecked(
                        toolsRepository + "//third_party/java/j2objc:jre_core_lib")))
        .add(
            attr("$xcrunwrapper", LABEL)
                .cfg(HostTransition.createFactory())
                .exec()
                .value(Label.parseAbsoluteUnchecked(toolsRepository + "//tools/objc:xcrunwrapper")))
        .add(
            attr(ObjcRuleClasses.LIBTOOL_ATTRIBUTE, LABEL)
                .cfg(HostTransition.createFactory())
                .exec()
                .value(Label.parseAbsoluteUnchecked(toolsRepository + "//tools/objc:libtool")))
        .add(
            attr(XcodeConfigRule.XCODE_CONFIG_ATTR_NAME, LABEL)
                .allowedRuleClasses("xcode_config")
                .checkConstraints()
                .direct_compile_time_input()
                .value(AppleToolchain.getXcodeConfigLabel(toolsRepository)))
        .add(
            attr("$zipper", LABEL)
                .cfg(HostTransition.createFactory())
                .exec()
                .value(Label.parseAbsoluteUnchecked(toolsRepository + "//tools/zip:zipper")))
        .add(
            attr(J2OBJC_PROTO_TOOLCHAIN_ATTR, LABEL)
                .legacyAllowAnyFileType()
                .value(
                    getProtoToolchainLabel(
                        toolsRepository + "//tools/j2objc:j2objc_proto_toolchain")))
        .add(attr(":j2objc_cc_toolchain", LABEL).value(ccToolchain))
        .build();
  }

  @Override
  public ConfiguredAspect create(
      ConfiguredTargetAndData ctadBase,
      RuleContext ruleContext,
      AspectParameters parameters,
      String toolsRepository)
      throws InterruptedException, ActionConflictException {
    ConfiguredTarget base = ctadBase.getConfiguredTarget();
    if (isProtoRule(base)) {
      return proto(base, ruleContext, parameters);
    } else {
      return java(base, ruleContext, parameters);
    }
  }

  private ConfiguredAspect buildAspect(
      ConfiguredTarget base,
      RuleContext ruleContext,
      AspectParameters parameters,
      J2ObjcSource j2ObjcSource,
      J2ObjcMappingFileProvider directJ2ObjcMappingFileProvider,
      Iterable<Attribute> depAttributes,
      List<TransitiveInfoCollection> otherDeps)
      throws InterruptedException, ActionConflictException {
    ConfiguredAspect.Builder builder = new ConfiguredAspect.Builder(this, parameters, ruleContext);
    ObjcCommon common;

    if (!Iterables.isEmpty(j2ObjcSource.getObjcSrcs())) {
      common =
          common(
              ruleContext,
              j2ObjcSource.getObjcSrcs(),
              j2ObjcSource.getObjcHdrs(),
              j2ObjcSource.getHeaderSearchPaths(),
              depAttributes,
              otherDeps);

      try {
        CcToolchainProvider ccToolchain =
            CppHelper.getToolchain(ruleContext, ":j2objc_cc_toolchain");
        CompilationSupport compilationSupport =
            new CompilationSupport.Builder()
                .setRuleContext(ruleContext)
                .setToolchainProvider(ccToolchain)
                .setIntermediateArtifacts(ObjcRuleClasses.j2objcIntermediateArtifacts(ruleContext))
                .doNotUsePch()
                .build();

        compilationSupport
            .registerCompileAndArchiveActions(
                common, EXTRA_COMPILE_ARGS, ImmutableList.<PathFragment>of())
            .registerFullyLinkAction(
                common.getObjcProvider(),
                ruleContext.getImplicitOutputArtifact(CompilationSupport.FULLY_LINKED_LIB));
      } catch (RuleErrorException e) {
        ruleContext.ruleError(e.getMessage());
      }
    } else {
      common =
          common(
              ruleContext,
              ImmutableList.<Artifact>of(),
              ImmutableList.<Artifact>of(),
              ImmutableList.<PathFragment>of(),
              depAttributes,
              otherDeps);
    }

    return builder
        .addProvider(
            exportedJ2ObjcMappingFileProvider(base, ruleContext, directJ2ObjcMappingFileProvider))
        .addNativeDeclaredProvider(common.getObjcProvider())
        .build();
  }

  private ConfiguredAspect java(
      ConfiguredTarget base, RuleContext ruleContext, AspectParameters parameters)
      throws InterruptedException, ActionConflictException {
    JavaCompilationArgsProvider compilationArgsProvider =
        JavaInfo.getProvider(JavaCompilationArgsProvider.class, base);
    JavaSourceInfoProvider sourceInfoProvider =
            JavaInfo.getProvider(JavaSourceInfoProvider.class, base);
    JavaGenJarsProvider genJarProvider = JavaInfo.getProvider(JavaGenJarsProvider.class, base);
    ImmutableSet.Builder<Artifact> javaSourceFilesBuilder = ImmutableSet.builder();
    ImmutableSet.Builder<Artifact> javaSourceJarsBuilder = ImmutableSet.builder();
    if (sourceInfoProvider != null) {
      javaSourceFilesBuilder.addAll(sourceInfoProvider.getSourceFiles());
      javaSourceJarsBuilder
          .addAll(sourceInfoProvider.getSourceJars())
          .addAll(sourceInfoProvider.getSourceJarsForJarFiles());
    }

    if (genJarProvider != null && genJarProvider.getGenSourceJar() != null) {
      javaSourceJarsBuilder.add(genJarProvider.getGenSourceJar());
    }

    ImmutableSet<Artifact> javaSourceFiles = javaSourceFilesBuilder.build();
    ImmutableSet<Artifact> javaSourceJars = javaSourceJarsBuilder.build();
    J2ObjcSource j2ObjcSource = javaJ2ObjcSource(ruleContext, javaSourceFiles, javaSourceJars);
    J2ObjcMappingFileProvider depJ2ObjcMappingFileProvider =
        depJ2ObjcMappingFileProvider(ruleContext);

    J2ObjcMappingFileProvider directJ2ObjcMappingFileProvider;
    if (Iterables.isEmpty(j2ObjcSource.getObjcSrcs())) {
      directJ2ObjcMappingFileProvider = new J2ObjcMappingFileProvider.Builder().build();
    } else {
      directJ2ObjcMappingFileProvider =
          createJ2ObjcTranspilationAction(
              ruleContext,
              javaSourceFiles,
              javaSourceJars,
              depJ2ObjcMappingFileProvider,
              compilationArgsProvider,
              j2ObjcSource);
    }
    return buildAspect(
        base,
        ruleContext,
        parameters,
        j2ObjcSource,
        directJ2ObjcMappingFileProvider,
        JAVA_DEPENDENT_ATTRIBUTES,
        ImmutableList.of());
  }

  private ConfiguredAspect proto(
      ConfiguredTarget base, RuleContext ruleContext, AspectParameters parameters)
      throws InterruptedException, ActionConflictException {
    ProtoInfo protoInfo = base.get(ProtoInfo.PROVIDER);
    ImmutableList<Artifact> protoSources = protoInfo.getDirectProtoSources();

    ProtoLangToolchainProvider protoToolchain =
        ruleContext.getPrerequisite(
            J2OBJC_PROTO_TOOLCHAIN_ATTR, TARGET, ProtoLangToolchainProvider.class);
    // Avoid pulling in any generated files from blacklisted protos.
    ProtoSourceFileBlacklist protoBlacklist =
        new ProtoSourceFileBlacklist(ruleContext, protoToolchain.blacklistedProtos().toList());

    ImmutableList<Artifact> filteredProtoSources =
        ImmutableList.copyOf(protoBlacklist.filter(protoSources));
    J2ObjcSource j2ObjcSource = protoJ2ObjcSource(ruleContext, filteredProtoSources);

    J2ObjcMappingFileProvider directJ2ObjcMappingFileProvider;
    if (Iterables.isEmpty(j2ObjcSource.getObjcSrcs())) {
      directJ2ObjcMappingFileProvider = new J2ObjcMappingFileProvider.Builder().build();
    } else {
      directJ2ObjcMappingFileProvider =
          createJ2ObjcProtoCompileActions(
              base, protoToolchain, ruleContext, filteredProtoSources, j2ObjcSource);
    }

    return buildAspect(
        base,
        ruleContext,
        parameters,
        j2ObjcSource,
        directJ2ObjcMappingFileProvider,
        PROTO_DEPENDENT_ATTRIBUTES,
        ImmutableList.of(protoToolchain.runtime()));
  }

  private static J2ObjcMappingFileProvider exportedJ2ObjcMappingFileProvider(
      ConfiguredTarget base,
      RuleContext ruleContext,
      J2ObjcMappingFileProvider directJ2ObjcMappingFileProvider) {
    J2ObjcMappingFileProvider depJ2ObjcMappingFileProvider =
        depJ2ObjcMappingFileProvider(ruleContext);

    NestedSetBuilder<Artifact> exportedHeaderMappingFiles =
        NestedSetBuilder.<Artifact>stableOrder()
            .addTransitive(directJ2ObjcMappingFileProvider.getHeaderMappingFiles());

    NestedSetBuilder<Artifact> exportedClassMappingFiles =
        NestedSetBuilder.<Artifact>stableOrder()
            .addTransitive(directJ2ObjcMappingFileProvider.getClassMappingFiles())
            .addTransitive(depJ2ObjcMappingFileProvider.getClassMappingFiles());

    NestedSetBuilder<Artifact> exportedDependencyMappingFiles =
        NestedSetBuilder.<Artifact>stableOrder()
            .addTransitive(directJ2ObjcMappingFileProvider.getDependencyMappingFiles())
            .addTransitive(depJ2ObjcMappingFileProvider.getDependencyMappingFiles());

    NestedSetBuilder<Artifact> archiveSourceMappingFiles =
        NestedSetBuilder.<Artifact>stableOrder()
            .addTransitive(directJ2ObjcMappingFileProvider.getArchiveSourceMappingFiles())
            .addTransitive(depJ2ObjcMappingFileProvider.getArchiveSourceMappingFiles());

    // J2ObjC merges all transitive input header mapping files into one header mapping file,
    // so we only need to re-export other dependent output header mapping files in proto rules and
    // rules where J2ObjC is not run (e.g., no sources).
    // We also add the transitive header mapping files if experimental J2ObjC header mapping is
    // turned on. The experimental support does not merge transitive input header mapping files.
    boolean experimentalJ2ObjcHeaderMap =
        ruleContext.getFragment(J2ObjcConfiguration.class).experimentalJ2ObjcHeaderMap();
    if (isProtoRule(base) || exportedHeaderMappingFiles.isEmpty() || experimentalJ2ObjcHeaderMap) {
      exportedHeaderMappingFiles.addTransitive(
          depJ2ObjcMappingFileProvider.getHeaderMappingFiles());
    }

    return new J2ObjcMappingFileProvider(
        exportedHeaderMappingFiles.build(),
        exportedClassMappingFiles.build(),
        exportedDependencyMappingFiles.build(),
        archiveSourceMappingFiles.build());
  }

  private static J2ObjcMappingFileProvider depJ2ObjcMappingFileProvider(RuleContext ruleContext) {
    NestedSetBuilder<Artifact> depsHeaderMappingsBuilder = NestedSetBuilder.stableOrder();
    NestedSetBuilder<Artifact> depsClassMappingsBuilder = NestedSetBuilder.stableOrder();
    NestedSetBuilder<Artifact> depsDependencyMappingsBuilder = NestedSetBuilder.stableOrder();
    NestedSetBuilder<Artifact> depsArchiveSourceMappingsBuilder = NestedSetBuilder.stableOrder();

    for (J2ObjcMappingFileProvider mapping : getJ2ObjCMappings(ruleContext)) {
      depsHeaderMappingsBuilder.addTransitive(mapping.getHeaderMappingFiles());
      depsClassMappingsBuilder.addTransitive(mapping.getClassMappingFiles());
      depsDependencyMappingsBuilder.addTransitive(mapping.getDependencyMappingFiles());
      depsArchiveSourceMappingsBuilder.addTransitive(mapping.getArchiveSourceMappingFiles());
    }

    return new J2ObjcMappingFileProvider(
        depsHeaderMappingsBuilder.build(),
        depsClassMappingsBuilder.build(),
        depsDependencyMappingsBuilder.build(),
        depsArchiveSourceMappingsBuilder.build());
  }

  private static ImmutableList<String> sourceJarFlags(RuleContext ruleContext) {
    return ImmutableList.of(
        "--output_gen_source_dir",
        j2ObjcSourceJarTranslatedSourceFiles(ruleContext).getExecPathString(),
        "--output_gen_header_dir",
        j2objcSourceJarTranslatedHeaderFiles(ruleContext).getExecPathString());
  }

  private static J2ObjcMappingFileProvider createJ2ObjcTranspilationAction(
      RuleContext ruleContext,
      Iterable<Artifact> sources,
      Iterable<Artifact> sourceJars,
      J2ObjcMappingFileProvider depJ2ObjcMappingFileProvider,
      JavaCompilationArgsProvider compArgsProvider,
      J2ObjcSource j2ObjcSource) {
    CustomCommandLine.Builder argBuilder = CustomCommandLine.builder();
    PathFragment javaExecutable = JavaCommon.getHostJavaExecutable(ruleContext);
    argBuilder.add("--java", javaExecutable.getPathString());

    Artifact j2ObjcDeployJar = ruleContext.getPrerequisiteArtifact("$j2objc", Mode.HOST);
    argBuilder.addExecPath("--j2objc", j2ObjcDeployJar);

    argBuilder.add("--main_class").add("com.google.devtools.j2objc.J2ObjC");
    argBuilder.add("--objc_file_path").addPath(j2ObjcSource.getObjcFilePath());

    Artifact outputDependencyMappingFile = j2ObjcOutputDependencyMappingFile(ruleContext);
    argBuilder.addExecPath("--output_dependency_mapping_file", outputDependencyMappingFile);

    if (!Iterables.isEmpty(sourceJars)) {
      argBuilder.addExecPaths(
          "--src_jars", VectorArg.join(",").each(ImmutableList.copyOf(sourceJars)));
      argBuilder.addAll(sourceJarFlags(ruleContext));
    }

    Iterable<String> translationFlags = ruleContext
        .getFragment(J2ObjcConfiguration.class)
        .getTranslationFlags();
    argBuilder.addAll(ImmutableList.copyOf(translationFlags));

    NestedSet<Artifact> depsHeaderMappingFiles =
        depJ2ObjcMappingFileProvider.getHeaderMappingFiles();
    if (!depsHeaderMappingFiles.isEmpty()) {
      argBuilder.addExecPaths("--header-mapping", VectorArg.join(",").each(depsHeaderMappingFiles));
    }

    boolean experimentalJ2ObjcHeaderMap =
        ruleContext.getFragment(J2ObjcConfiguration.class).experimentalJ2ObjcHeaderMap();
    Artifact outputHeaderMappingFile = j2ObjcOutputHeaderMappingFile(ruleContext);
    if (!experimentalJ2ObjcHeaderMap) {
      argBuilder.addExecPath("--output-header-mapping", outputHeaderMappingFile);
    }

    NestedSet<Artifact> depsClassMappingFiles = depJ2ObjcMappingFileProvider.getClassMappingFiles();
    if (!depsClassMappingFiles.isEmpty()) {
      argBuilder.addExecPaths("--mapping", VectorArg.join(",").each(depsClassMappingFiles));
    }

    Artifact archiveSourceMappingFile = j2ObjcOutputArchiveSourceMappingFile(ruleContext);
    argBuilder.addExecPath("--output_archive_source_mapping_file", archiveSourceMappingFile);

    Artifact compiledLibrary = ObjcRuleClasses.j2objcIntermediateArtifacts(ruleContext).archive();
    argBuilder.addExecPath("--compiled_archive_file_path", compiledLibrary);

    Artifact bootclasspathJar = ruleContext.getPrerequisiteArtifact("$jre_emul_jar", Mode.HOST);
    argBuilder.addFormatted("-Xbootclasspath:%s", bootclasspathJar);

    // A valid Java system module contains 3 files. The top directory contains a file "release".
    ImmutableList<Artifact> moduleFiles =
        ruleContext.getPrerequisiteArtifacts("$jre_emul_module", Mode.HOST).list();
    for (Artifact a : moduleFiles) {
      if (a.getFilename().equals("release")) {
        argBuilder.add("--system", a.getDirname());
        break;
      }
    }

    Artifact deadCodeReport = ruleContext.getPrerequisiteArtifact(":dead_code_report", Mode.HOST);
    if (deadCodeReport != null) {
      argBuilder.addExecPath("--dead-code-report", deadCodeReport);
    }

    argBuilder.add("-d").addPath(j2ObjcSource.getObjcFilePath());

    NestedSet<Artifact> compileTimeJars = compArgsProvider.getTransitiveCompileTimeJars();
    if (!compileTimeJars.isEmpty()) {
      argBuilder.addExecPaths("-classpath", VectorArg.join(":").each(compileTimeJars));
    }

    argBuilder.addExecPaths(ImmutableList.copyOf(sources));

    SpawnAction.Builder transpilationAction =
        new SpawnAction.Builder()
            .setMnemonic("TranspilingJ2objc")
            .setExecutable(ruleContext.getPrerequisiteArtifact("$j2objc_wrapper", Mode.HOST))
            .addInput(ruleContext.getPrerequisiteArtifact("$j2objc_wrapper", Mode.HOST))
            .addInput(j2ObjcDeployJar)
            .addInput(bootclasspathJar)
            .addInputs(moduleFiles)
            .addInputs(sources)
            .addInputs(sourceJars)
            .addTransitiveInputs(compileTimeJars)
            .addTransitiveInputs(JavaRuntimeInfo.forHost(ruleContext).javaBaseInputsMiddleman())
            .addTransitiveInputs(depsHeaderMappingFiles)
            .addTransitiveInputs(depsClassMappingFiles)
            .addCommandLine(
                argBuilder.build(),
                ParamFileInfo.builder(ParameterFile.ParameterFileType.UNQUOTED)
                    .setCharset(ISO_8859_1)
                    .setUseAlways(true)
                    .build())
            .addOutputs(j2ObjcSource.getObjcSrcs())
            .addOutputs(j2ObjcSource.getObjcHdrs())
            .addOutput(outputDependencyMappingFile)
            .addOutput(archiveSourceMappingFile);

    if (deadCodeReport != null) {
      transpilationAction.addInput(deadCodeReport);
    }

    if (!experimentalJ2ObjcHeaderMap) {
      transpilationAction.addOutput(outputHeaderMappingFile);
    }
    ruleContext.registerAction(transpilationAction.build(ruleContext));

    if (experimentalJ2ObjcHeaderMap) {
      CustomCommandLine.Builder headerMapCommandLine = CustomCommandLine.builder();
      if (!Iterables.isEmpty(sources)) {
        headerMapCommandLine.addExecPaths(
            "--source_files", VectorArg.join(",").each(ImmutableList.copyOf(sources)));
      }
      if (!Iterables.isEmpty(sourceJars)) {
        headerMapCommandLine.addExecPaths(
            "--source_jars", VectorArg.join(",").each(ImmutableList.copyOf(sourceJars)));
      }
      headerMapCommandLine.addExecPath("--output_mapping_file", outputHeaderMappingFile);
      ruleContext.registerAction(
          new SpawnAction.Builder()
              .setMnemonic("GenerateJ2objcHeaderMap")
              .setExecutable(ruleContext.getPrerequisiteArtifact("$j2objc_header_map", Mode.HOST))
              .addInput(ruleContext.getPrerequisiteArtifact("$j2objc_header_map", Mode.HOST))
              .addInputs(sources)
              .addInputs(sourceJars)
              .addCommandLine(
                  headerMapCommandLine.build(),
                  ParamFileInfo.builder(ParameterFileType.SHELL_QUOTED).build())
              .addOutput(outputHeaderMappingFile)
              .build(ruleContext));
    }

    return new J2ObjcMappingFileProvider(
        NestedSetBuilder.<Artifact>stableOrder().add(outputHeaderMappingFile).build(),
        NestedSetBuilder.<Artifact>stableOrder().build(),
        NestedSetBuilder.<Artifact>stableOrder().add(outputDependencyMappingFile).build(),
        NestedSetBuilder.<Artifact>stableOrder().add(archiveSourceMappingFile).build());
  }

  private J2ObjcMappingFileProvider createJ2ObjcProtoCompileActions(
      ConfiguredTarget base,
      ProtoLangToolchainProvider protoToolchain,
      RuleContext ruleContext,
      Iterable<Artifact> filteredProtoSources,
      J2ObjcSource j2ObjcSource) {
    Iterable<Artifact> outputHeaderMappingFiles =
        ProtoCommon.getGeneratedOutputs(
            ruleContext, ImmutableList.copyOf(filteredProtoSources), ".j2objc.mapping");
    Iterable<Artifact> outputClassMappingFiles =
        ProtoCommon.getGeneratedOutputs(
            ruleContext, ImmutableList.copyOf(filteredProtoSources), ".clsmap.properties");
    ImmutableList<Artifact> outputs =
        ImmutableList.<Artifact>builder()
            .addAll(j2ObjcSource.getObjcSrcs())
            .addAll(j2ObjcSource.getObjcHdrs())
            .addAll(outputHeaderMappingFiles)
            .addAll(outputClassMappingFiles)
            .build();

    String genfilesPath = getProtoOutputRoot(ruleContext).getPathString();

    ProtoInfo protoInfo = base.get(ProtoInfo.PROVIDER);

    ImmutableList.Builder<ProtoCompileActionBuilder.ToolchainInvocation> invocations =
        ImmutableList.builder();
    invocations.add(
        new ProtoCompileActionBuilder.ToolchainInvocation(
            "j2objc", checkNotNull(protoToolchain), genfilesPath));
    ProtoCompileActionBuilder.registerActions(
        ruleContext,
        invocations.build(),
        protoInfo,
        ruleContext.getLabel(),
        outputs,
        "j2objc",
        Exports.DO_NOT_USE,
        shouldAllowProtoServices(ruleContext) ? Services.ALLOW : Services.DISALLOW);

    return new J2ObjcMappingFileProvider(
        NestedSetBuilder.<Artifact>stableOrder().addAll(outputHeaderMappingFiles).build(),
        NestedSetBuilder.<Artifact>stableOrder().addAll(outputClassMappingFiles).build(),
        NestedSetBuilder.<Artifact>stableOrder().build(),
        NestedSetBuilder.<Artifact>stableOrder().build());
  }

  private static List<? extends J2ObjcMappingFileProvider> getJ2ObjCMappings(RuleContext context) {
    ImmutableList.Builder<J2ObjcMappingFileProvider> mappingFileProviderBuilder =
        new ImmutableList.Builder<>();
    addJ2ObjCMappingsForAttribute(mappingFileProviderBuilder, context, "deps");
    addJ2ObjCMappingsForAttribute(mappingFileProviderBuilder, context, "runtime_deps");
    addJ2ObjCMappingsForAttribute(mappingFileProviderBuilder, context, "exports");
    return mappingFileProviderBuilder.build();
  }

  private static void addJ2ObjCMappingsForAttribute(
      ImmutableList.Builder<J2ObjcMappingFileProvider> builder, RuleContext context,
      String attributeName) {
    if (context.attributes().has(attributeName, BuildType.LABEL_LIST)) {
      for (TransitiveInfoCollection dependencyInfoDatum :
          context.getPrerequisites(attributeName, Mode.TARGET)) {
        J2ObjcMappingFileProvider provider =
            dependencyInfoDatum.getProvider(J2ObjcMappingFileProvider.class);
        if (provider != null) {
          builder.add(provider);
        }
      }
    }
  }

  private static Artifact j2ObjcOutputHeaderMappingFile(RuleContext ruleContext) {
    return ObjcRuleClasses.artifactByAppendingToBaseName(ruleContext, ".mapping.j2objc");
  }

  private static Artifact j2ObjcOutputDependencyMappingFile(RuleContext ruleContext) {
    return ObjcRuleClasses.artifactByAppendingToBaseName(ruleContext, ".dependency_mapping.j2objc");
  }

  private static Artifact j2ObjcOutputArchiveSourceMappingFile(RuleContext ruleContext) {
    return ObjcRuleClasses.artifactByAppendingToBaseName(
        ruleContext, ".archive_source_mapping.j2objc");
  }

  private static Artifact j2ObjcSourceJarTranslatedSourceFiles(RuleContext ruleContext) {
    PathFragment rootRelativePath = ruleContext
        .getUniqueDirectory("_j2objc/src_jar_files")
        .getRelative("source_files");
    return ruleContext.getTreeArtifact(rootRelativePath, ruleContext.getBinOrGenfilesDirectory());
  }

  /**
   * Returns a unique path fragment for j2objc headers. The slightly shorter path is
   * useful for very large app builds, which otherwise may have command lines that are
   * too long to be executable.
   */
  private static String j2objcHeaderBase(RuleContext ruleContext) {
    boolean shorterPath =
        ruleContext.getFragment(J2ObjcConfiguration.class).experimentalShorterHeaderPath();
    return shorterPath ? "_ios" : "_j2objc";
  }

  private static Artifact j2objcSourceJarTranslatedHeaderFiles(RuleContext ruleContext) {
    String uniqueDirectoryPath = j2objcHeaderBase(ruleContext) + "/src_jar_files";
    PathFragment rootRelativePath =
        ruleContext.getUniqueDirectory(uniqueDirectoryPath).getRelative("header_files");
    return ruleContext.getTreeArtifact(rootRelativePath, ruleContext.getBinOrGenfilesDirectory());
  }

  private static J2ObjcSource javaJ2ObjcSource(
      RuleContext ruleContext,
      Iterable<Artifact> javaInputSourceFiles,
      Iterable<Artifact> javaSourceJarFiles) {
    PathFragment objcFileRootRelativePath =
        ruleContext.getUniqueDirectory(j2objcHeaderBase(ruleContext));
    PathFragment objcFileRootExecPath = ruleContext
        .getConfiguration()
        .getBinFragment()
        .getRelative(objcFileRootRelativePath);
    Iterable<Artifact> objcSrcs = getOutputObjcFiles(ruleContext, javaInputSourceFiles,
        objcFileRootRelativePath, ".m");
    Iterable<Artifact> objcHdrs = getOutputObjcFiles(ruleContext, javaInputSourceFiles,
        objcFileRootRelativePath, ".h");
    Iterable<PathFragment> headerSearchPaths = J2ObjcLibrary.j2objcSourceHeaderSearchPaths(
        ruleContext, objcFileRootExecPath, javaInputSourceFiles);

    Optional<Artifact> sourceJarTranslatedSrcs = Optional.absent();
    Optional<Artifact> sourceJarTranslatedHdrs = Optional.absent();
    Optional<PathFragment> sourceJarFileHeaderSearchPaths = Optional.absent();

    if (!Iterables.isEmpty(javaSourceJarFiles)) {
      sourceJarTranslatedSrcs = Optional.of(j2ObjcSourceJarTranslatedSourceFiles(ruleContext));
      sourceJarTranslatedHdrs = Optional.of(j2objcSourceJarTranslatedHeaderFiles(ruleContext));
      sourceJarFileHeaderSearchPaths = Optional.of(sourceJarTranslatedHdrs.get().getExecPath());
    }

    return new J2ObjcSource(
        ruleContext.getRule().getLabel(),
        Iterables.concat(objcSrcs, sourceJarTranslatedSrcs.asSet()),
        Iterables.concat(objcHdrs, sourceJarTranslatedHdrs.asSet()),
        objcFileRootExecPath,
        SourceType.JAVA,
        Iterables.concat(headerSearchPaths, sourceJarFileHeaderSearchPaths.asSet()));
  }

  private static J2ObjcSource protoJ2ObjcSource(
      RuleContext ruleContext, ImmutableList<Artifact> protoSources) {
    PathFragment objcFileRootExecPath = getProtoOutputRoot(ruleContext);

    Iterable<PathFragment> headerSearchPaths =
        J2ObjcLibrary.j2objcSourceHeaderSearchPaths(
            ruleContext, objcFileRootExecPath, protoSources);

    return new J2ObjcSource(
        ruleContext.getTarget().getLabel(),
        ProtoCommon.getGeneratedOutputs(ruleContext, protoSources, ".j2objc.pb.m"),
        ProtoCommon.getGeneratedOutputs(ruleContext, protoSources, ".j2objc.pb.h"),
        objcFileRootExecPath,
        SourceType.PROTO,
        headerSearchPaths);
  }

  private static PathFragment getProtoOutputRoot(RuleContext ruleContext) {
    return ruleContext
        .getConfiguration()
        .getGenfilesFragment()
        .getRelative(
            ruleContext.getLabel().getPackageIdentifier().getRepository().getPathUnderExecRoot());
  }

  private static boolean isProtoRule(ConfiguredTarget base) {
    return base.get(ProtoInfo.PROVIDER) != null;
  }

  private static Iterable<Artifact> getOutputObjcFiles(
      RuleContext ruleContext,
      Iterable<Artifact> javaSrcs,
      PathFragment objcFileRootRelativePath,
      String suffix) {
    ImmutableList.Builder<Artifact> objcSources = ImmutableList.builder();

    for (Artifact javaSrc : javaSrcs) {
      objcSources.add(ruleContext.getRelatedArtifact(
          objcFileRootRelativePath.getRelative(javaSrc.getExecPath()), suffix));
    }

    return objcSources.build();
  }

  /** Sets up and returns an {@link ObjcCommon} object containing the J2ObjC-translated code. */
  static ObjcCommon common(
      RuleContext ruleContext,
      Iterable<Artifact> transpiledSources,
      Iterable<Artifact> transpiledHeaders,
      Iterable<PathFragment> headerSearchPaths,
      Iterable<Attribute> dependentAttributes,
      List<TransitiveInfoCollection> otherObjcProviders)
      throws InterruptedException {
    ObjcCommon.Builder builder = new ObjcCommon.Builder(ruleContext);
    IntermediateArtifacts intermediateArtifacts =
        ObjcRuleClasses.j2objcIntermediateArtifacts(ruleContext);

    if (!Iterables.isEmpty(transpiledSources) || !Iterables.isEmpty(transpiledHeaders)) {
      CompilationArtifacts compilationArtifacts = new CompilationArtifacts.Builder()
          .addNonArcSrcs(transpiledSources)
          .setIntermediateArtifacts(intermediateArtifacts)
          .addAdditionalHdrs(transpiledHeaders)
          .build();
      builder.setCompilationArtifacts(compilationArtifacts);
      builder.setHasModuleMap();
    }

    for (Attribute dependentAttribute : dependentAttributes) {
      if (ruleContext.attributes().has(dependentAttribute.getName(), BuildType.LABEL_LIST)
          || ruleContext.attributes().has(dependentAttribute.getName(), BuildType.LABEL)) {
        Iterable<ObjcProvider> depObjcProviders =
            ruleContext.getPrerequisites(
                dependentAttribute.getName(),
                dependentAttribute.getAccessMode(),
                ObjcProvider.SKYLARK_CONSTRUCTOR);
        builder.addDepObjcProviders(depObjcProviders);
        builder.addRepropagatedModuleMapObjcProviders(depObjcProviders);
      }
    }

    List<ObjcProvider> newOtherDeps =
        otherObjcProviders
            .stream()
            .map(d -> d.get(ObjcProvider.SKYLARK_CONSTRUCTOR))
            .collect(Collectors.toList());
    // We can't just use addDeps since that now takes ConfiguredTargetAndTargets and we only have
    // TransitiveInfoCollections
    builder.addDepObjcProviders(newOtherDeps);

    return builder
        .addIncludes(headerSearchPaths)
        .setIntermediateArtifacts(intermediateArtifacts)
        .build();
  }
}