// 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.runtime.commands;

import static com.google.common.collect.ImmutableList.toImmutableList;
import static java.nio.charset.StandardCharsets.ISO_8859_1;

import com.google.common.base.Joiner;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.ImmutableSortedMap;
import com.google.common.collect.ImmutableSortedSet;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.devtools.build.lib.actions.ActionEnvironment;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.ArtifactPathResolver;
import com.google.devtools.build.lib.actions.CommandLine;
import com.google.devtools.build.lib.actions.CommandLineExpansionException;
import com.google.devtools.build.lib.actions.EnvironmentalExecException;
import com.google.devtools.build.lib.actions.ExecException;
import com.google.devtools.build.lib.analysis.AliasProvider;
import com.google.devtools.build.lib.analysis.ConfiguredTarget;
import com.google.devtools.build.lib.analysis.FilesToRunProvider;
import com.google.devtools.build.lib.analysis.RunEnvironmentInfo;
import com.google.devtools.build.lib.analysis.RunfilesSupport;
import com.google.devtools.build.lib.analysis.ShToolchain;
import com.google.devtools.build.lib.analysis.config.BuildConfigurationValue;
import com.google.devtools.build.lib.analysis.config.CoreOptions;
import com.google.devtools.build.lib.analysis.config.RunUnder;
import com.google.devtools.build.lib.analysis.test.TestConfiguration;
import com.google.devtools.build.lib.analysis.test.TestProvider;
import com.google.devtools.build.lib.analysis.test.TestRunnerAction;
import com.google.devtools.build.lib.analysis.test.TestStrategy;
import com.google.devtools.build.lib.analysis.test.TestTargetExecutionSettings;
import com.google.devtools.build.lib.buildtool.BuildRequest;
import com.google.devtools.build.lib.buildtool.BuildRequestOptions;
import com.google.devtools.build.lib.buildtool.BuildResult;
import com.google.devtools.build.lib.buildtool.BuildTool;
import com.google.devtools.build.lib.buildtool.OutputDirectoryLinksUtils;
import com.google.devtools.build.lib.buildtool.PathPrettyPrinter;
import com.google.devtools.build.lib.events.Event;
import com.google.devtools.build.lib.events.Reporter;
import com.google.devtools.build.lib.exec.ExecutionOptions;
import com.google.devtools.build.lib.exec.SymlinkTreeHelper;
import com.google.devtools.build.lib.exec.TestPolicy;
import com.google.devtools.build.lib.packages.InputFile;
import com.google.devtools.build.lib.packages.NoSuchPackageException;
import com.google.devtools.build.lib.packages.NoSuchTargetException;
import com.google.devtools.build.lib.packages.NonconfigurableAttributeMapper;
import com.google.devtools.build.lib.packages.OutputFile;
import com.google.devtools.build.lib.packages.Rule;
import com.google.devtools.build.lib.packages.Target;
import com.google.devtools.build.lib.packages.TargetUtils;
import com.google.devtools.build.lib.packages.Type;
import com.google.devtools.build.lib.pkgcache.LoadingFailedException;
import com.google.devtools.build.lib.runtime.BlazeCommand;
import com.google.devtools.build.lib.runtime.BlazeCommandResult;
import com.google.devtools.build.lib.runtime.BlazeRuntime;
import com.google.devtools.build.lib.runtime.BlazeServerStartupOptions;
import com.google.devtools.build.lib.runtime.Command;
import com.google.devtools.build.lib.runtime.CommandEnvironment;
import com.google.devtools.build.lib.server.CommandProtos.EnvironmentVariable;
import com.google.devtools.build.lib.server.CommandProtos.ExecRequest;
import com.google.devtools.build.lib.server.FailureDetails;
import com.google.devtools.build.lib.server.FailureDetails.FailureDetail;
import com.google.devtools.build.lib.server.FailureDetails.Interrupted;
import com.google.devtools.build.lib.server.FailureDetails.RunCommand.Code;
import com.google.devtools.build.lib.shell.ShellUtils;
import com.google.devtools.build.lib.util.CommandDescriptionForm;
import com.google.devtools.build.lib.util.CommandFailureUtils;
import com.google.devtools.build.lib.util.DetailedExitCode;
import com.google.devtools.build.lib.util.FileType;
import com.google.devtools.build.lib.util.InterruptedFailureDetails;
import com.google.devtools.build.lib.util.OS;
import com.google.devtools.build.lib.util.OptionsUtils;
import com.google.devtools.build.lib.util.ShellEscaper;
import com.google.devtools.build.lib.vfs.FileSystemUtils;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.common.options.Option;
import com.google.devtools.common.options.OptionDocumentationCategory;
import com.google.devtools.common.options.OptionEffectTag;
import com.google.devtools.common.options.OptionsBase;
import com.google.devtools.common.options.OptionsParser;
import com.google.devtools.common.options.OptionsParsingResult;
import com.google.protobuf.ByteString;
import java.io.IOException;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import javax.annotation.Nullable;

/** Builds and run a target with the given command line arguments. */
@Command(
    name = "run",
    builds = true,
    options = {RunCommand.RunOptions.class},
    inherits = {BuildCommand.class},
    shortDescription = "Runs the specified target.",
    help = "resource:run.txt",
    allowResidue = true,
    hasSensitiveResidue = true,
    completion = "label-bin")
public class RunCommand implements BlazeCommand {
  /** Options for the "run" command. */
  public static class RunOptions extends OptionsBase {
    @Option(
        name = "script_path",
        defaultValue = "null",
        documentationCategory = OptionDocumentationCategory.OUTPUT_PARAMETERS,
        effectTags = {OptionEffectTag.AFFECTS_OUTPUTS, OptionEffectTag.EXECUTION},
        converter = OptionsUtils.PathFragmentConverter.class,
        help =
            "If set, write a shell script to the given file which invokes the target. If this"
                + " option is set, the target is not run from %{product}. Use '%{product} run"
                + " --script_path=foo //foo && ./foo' to invoke target '//foo' This differs from"
                + " '%{product} run //foo' in that the %{product} lock is released and the"
                + " executable is connected to the terminal's stdin.")
    public PathFragment scriptPath;
  }

  private static final String NO_TARGET_MESSAGE = "No targets found to run";

  private static final String MULTIPLE_TESTS_MESSAGE =
      "'run' only works with tests with one shard ('--test_sharding_strategy=disabled' is okay) "
          + "and without --runs_per_test";

  private static final FileType RUNFILES_MANIFEST = FileType.of(".runfiles_manifest");

  private static final ImmutableList<String> ENV_VARIABLES_TO_CLEAR =
      ImmutableList.of(
          // These variables are all used by runfiles libraries to locate the runfiles directory or
          // manifest and can cause incorrect behavior when set for the top-level binary run with
          // bazel run.
          "JAVA_RUNFILES",
          "RUNFILES_DIR",
          "RUNFILES_MANIFEST_FILE",
          "RUNFILES_MANIFEST_ONLY",
          "TEST_SRCDIR");

  /** The test policy to determine the environment variables from when running tests */
  private final TestPolicy testPolicy;

  public RunCommand(TestPolicy testPolicy) {
    this.testPolicy = testPolicy;
  }

  @Override
  public void editOptions(OptionsParser optionsParser) {}

  /**
   * Compute the arguments the binary should be run with by concatenating the arguments in its
   * {@code args} attribute and the arguments on the Blaze command line.
   */
  private static List<String> computeArgs(
      ConfiguredTarget targetToRun, List<String> commandLineArgs)
      throws InterruptedException, CommandLineExpansionException {
    List<String> args = Lists.newArrayList();

    FilesToRunProvider provider = targetToRun.getProvider(FilesToRunProvider.class);
    RunfilesSupport runfilesSupport = provider == null ? null : provider.getRunfilesSupport();
    if (runfilesSupport != null && runfilesSupport.getArgs() != null) {
      CommandLine targetArgs = runfilesSupport.getArgs();
      Iterables.addAll(args, targetArgs.arguments());
    }
    args.addAll(commandLineArgs);
    return args;
  }

  @Override
  public BlazeCommandResult exec(CommandEnvironment env, OptionsParsingResult options) {
    RunOptions runOptions = options.getOptions(RunOptions.class);
    // This list should look like: ["//executable:target", "arg1", "arg2"]
    List<String> targetAndArgs = options.getResidue();

    // The user must at the least specify an executable target.
    if (targetAndArgs.isEmpty()) {
      return reportAndCreateFailureResult(
          env, "Must specify a target to run", Code.NO_TARGET_SPECIFIED);
    }
    String targetString = targetAndArgs.get(0);
    RunUnder runUnder = options.getOptions(CoreOptions.class).runUnder;

    BuiltTargets builtTargets;
    try {
      builtTargets = runBuild(env, options, targetString, runUnder);
    } catch (RunCommandException e) {
      return e.result;
    }

    ImmutableList<String> commandLineArgs =
        ImmutableList.copyOf(targetAndArgs.subList(1, targetAndArgs.size()));
    RunCommandLine runCommandLine;
    try {
      runCommandLine = getCommandLineInfo(env, builtTargets, options, commandLineArgs, testPolicy);
    } catch (RunCommandException e) {
      return e.result;
    }

    if (runOptions.scriptPath != null) {
      String unisolatedCommand =
          CommandFailureUtils.describeCommand(
              CommandDescriptionForm.COMPLETE_UNISOLATED,
              /* prettyPrintArgs= */ false,
              runCommandLine.args,
              runCommandLine.runEnvironment,
              ENV_VARIABLES_TO_CLEAR,
              runCommandLine.workingDir.getPathString(),
              builtTargets.configuration.checksum(),
              /* executionPlatformAsLabelString= */ null);

      PathFragment shExecutable = ShToolchain.getPathForHost(builtTargets.configuration);
      if (shExecutable.isEmpty()) {
        return reportAndCreateFailureResult(
            env,
            "the \"run\" command needs a shell with \"--script_path\"; use the"
                + " --shell_executable=<path> flag to specify its path, e.g."
                + " --shell_executable=/bin/bash",
            Code.NO_SHELL_SPECIFIED);
      }

      try {
        writeScript(env, shExecutable, runOptions.scriptPath, unisolatedCommand);
        return BlazeCommandResult.success();
      } catch (IOException e) {
        String message = "Error writing run script: " + e.getMessage();
        return reportAndCreateFailureResult(env, message, Code.SCRIPT_WRITE_FAILURE);
      }
    }

    env.getReporter()
        .handle(
            Event.info(
                null,
                "Running command line: "
                    + ShellEscaper.escapeJoinAll(runCommandLine.prettyPrintArgs)));

    // In --batch, prioritize original client env-var values over those added by the c++ launcher.
    // Only necessary in --batch since the command runs as a subprocess of the java server.
    boolean batchMode =
        env.getRuntime()
            .getStartupOptionsProvider()
            .getOptions(BlazeServerStartupOptions.class)
            .batch;
    ImmutableSortedMap.Builder<String, String> runEnv =
        ImmutableSortedMap.<String, String>naturalOrder().putAll(runCommandLine.runEnvironment);
    if (batchMode) {
      runEnv.putAll(env.getClientEnv());
    }

    try {
      return BlazeCommandResult.execute(
          buildExecRequest(
              env,
              runCommandLine.workingDir,
              runCommandLine.args,
              runEnv.buildOrThrow(),
              ENV_VARIABLES_TO_CLEAR,
              builtTargets.configuration));
    } catch (RunCommandException e) {
      return e.result;
    }
  }

  private static BuiltTargets runBuild(
      CommandEnvironment env,
      OptionsParsingResult options,
      String targetString,
      @Nullable RunUnder runUnder)
      throws RunCommandException {
    ImmutableList<String> targetsToBuild =
        (runUnder != null) && (runUnder.getLabel() != null)
            ? ImmutableList.of(targetString, runUnder.getLabel().toString())
            : ImmutableList.of(targetString);
    BuildRequest request =
        BuildRequest.builder()
            .setCommandName(RunCommand.class.getAnnotation(Command.class).name())
            .setId(env.getCommandId())
            .setOptions(options)
            .setStartupOptions(env.getRuntime().getStartupOptionsProvider())
            .setOutErr(env.getReporter().getOutErr())
            .setTargets(targetsToBuild)
            .setStartTimeMillis(env.getCommandStartTime())
            .build();

    BuildResult buildResult =
        new BuildTool(env)
            .processRequest(
                request,
                (Collection<Target> tgts, boolean keepGoing) ->
                    validateTargets(
                        env.getReporter(), request.getTargets(), tgts, runUnder, keepGoing));
    if (!buildResult.getSuccess()) {
      env.getReporter().handle(Event.error("Build failed. Not running target"));
      throw new RunCommandException(
          BlazeCommandResult.detailedExitCode(buildResult.getDetailedExitCode()));
    }
    // Build succeeded - make sure outputs are available before attempting to use them.
    flushOutputs(env);

    return getBuiltTargets(buildResult, env, targetString, runUnder);
  }

  private static BuiltTargets getBuiltTargets(
      BuildResult result, CommandEnvironment env, String targetString, RunUnder runUnder)
      throws RunCommandException {
    Collection<ConfiguredTarget> topLevelTargets = result.getSuccessfulTargets();
    ConfiguredTarget targetToRun = null;
    ConfiguredTarget runUnderTarget = null;

    if (topLevelTargets != null) {
      // Make sure that we have exactly 1 built target (excluding --run_under) and that it is
      // executable. These checks should only fail if keepGoing is true, because we already did
      // validation before the build began in validateTargets().
      int maxTargets = runUnder != null && runUnder.getLabel() != null ? 2 : 1;
      if (topLevelTargets.size() > maxTargets) {
        throw new RunCommandException(
            reportAndCreateFailureResult(
                env,
                makeErrorMessageForNotHavingASingleTarget(
                    targetString,
                    Iterables.transform(topLevelTargets, ct -> ct.getLabel().toString())),
                Code.TOO_MANY_TARGETS_SPECIFIED));
      }

      for (ConfiguredTarget target : topLevelTargets) {
        BlazeCommandResult targetValidationResult = fullyValidateTarget(env, target);
        if (!targetValidationResult.isSuccess()) {
          throw new RunCommandException(targetValidationResult);
        }
        if (runUnder != null && target.getOriginalLabel().equals(runUnder.getLabel())) {
          if (runUnderTarget != null) {
            throw new RunCommandException(
                reportAndCreateFailureResult(
                    env,
                    "Can't identify the run_under target from multiple options?",
                    Code.RUN_UNDER_TARGET_NOT_BUILT));
          }
          runUnderTarget = target;
        } else if (targetToRun == null) {
          targetToRun = target;
        } else {
          throw new RunCommandException(
              reportAndCreateFailureResult(
                  env,
                  makeErrorMessageForNotHavingASingleTarget(
                      targetString,
                      Iterables.transform(topLevelTargets, ct -> ct.getLabel().toString())),
                  Code.TOO_MANY_TARGETS_SPECIFIED));
        }
      }
    }

    // Handle target & run_under referring to the same target.
    if (targetToRun == null && runUnderTarget != null) {
      targetToRun = runUnderTarget;
    }

    if (targetToRun == null) {
      throw new RunCommandException(
          reportAndCreateFailureResult(env, NO_TARGET_MESSAGE, Code.NO_TARGET_SPECIFIED));
    }

    BuildConfigurationValue configuration =
        env.getSkyframeExecutor()
            .getConfiguration(env.getReporter(), targetToRun.getConfigurationKey());
    if (configuration == null) {
      // The target may be an input file, which doesn't have a configuration. In that case, we
      // choose any target configuration.
      configuration = result.getBuildConfiguration();
    }

    if (!configuration.buildRunfilesManifests()) {
      throw new RunCommandException(
          reportAndCreateFailureResult(
              env,
              "--nobuild_runfile_manifests is incompatible with the \"run\" command",
              Code.RUN_PREREQ_UNMET));
    }

    // Ensure runfiles directories are constructed, both for the target to run
    // and the --run_under target. The path of the runfiles directory of the
    // target to run needs to be preserved, as it acts as the working directory.
    Path targetToRunRunfilesDir = null;
    RunfilesSupport targetToRunRunfilesSupport = null;
    for (ConfiguredTarget target : topLevelTargets) {
      FilesToRunProvider provider = target.getProvider(FilesToRunProvider.class);
      RunfilesSupport runfilesSupport = provider == null ? null : provider.getRunfilesSupport();

      if (runfilesSupport == null) {
        continue;
      }
      try {
        Path runfilesDir =
            ensureRunfilesBuilt(
                env,
                runfilesSupport,
                env.getSkyframeExecutor()
                    .getConfiguration(env.getReporter(), target.getConfigurationKey()));
        if (target == targetToRun) {
          targetToRunRunfilesDir = runfilesDir;
          targetToRunRunfilesSupport = runfilesSupport;
        }
      } catch (RunfilesException e) {
        env.getReporter().handle(Event.error(e.getMessage()));
        throw new RunCommandException(BlazeCommandResult.failureDetail(e.createFailureDetail()));
      } catch (InterruptedException e) {
        env.getReporter().handle(Event.error("Interrupted"));
        throw new RunCommandException(
            BlazeCommandResult.failureDetail(
                FailureDetail.newBuilder()
                    .setInterrupted(Interrupted.newBuilder().setCode(Interrupted.Code.INTERRUPTED))
                    .build()));
      }
    }

    return new BuiltTargets(
        targetToRun,
        targetToRunRunfilesDir,
        targetToRunRunfilesSupport,
        runUnderTarget,
        configuration);
  }

  /** Encapsulates information for launching the command specified by a run invocation. */
  private static class RunCommandLine {
    private final ImmutableList<String> args;
    private final ImmutableList<String> prettyPrintArgs;
    private final ImmutableSortedMap<String, String> runEnvironment;
    private final Path workingDir;

    private RunCommandLine(
        ImmutableList<String> args,
        ImmutableList<String> prettyPrintArgs,
        ImmutableSortedMap<String, String> runEnvironment,
        Path workingDir) {
      this.args = args;
      this.prettyPrintArgs = prettyPrintArgs;
      this.runEnvironment = runEnvironment;
      this.workingDir = workingDir;
    }
  }

  private static RunCommandLine getCommandLineInfo(
      CommandEnvironment env,
      BuiltTargets builtTargets,
      OptionsParsingResult options,
      ImmutableList<String> commandLineArgs,
      TestPolicy testPolicy)
      throws RunCommandException {
    Map<String, String> runEnvironment = new TreeMap<>();
    List<String> cmdLine = new ArrayList<>();
    List<String> prettyCmdLine = new ArrayList<>();
    Path workingDir;

    runEnvironment.put("BUILD_WORKSPACE_DIRECTORY", env.getWorkspace().getPathString());
    runEnvironment.put("BUILD_WORKING_DIRECTORY", env.getWorkingDirectory().getPathString());

    if (builtTargets.targetToRun.getProvider(TestProvider.class) != null) {
      // This is a test. Provide it with a reasonable approximation of the actual test environment
      ImmutableList<Artifact.DerivedArtifact> statusArtifacts =
          TestProvider.getTestStatusArtifacts(builtTargets.targetToRun);
      if (statusArtifacts.size() != 1) {
        throw new RunCommandException(
            reportAndCreateFailureResult(
                env, MULTIPLE_TESTS_MESSAGE, Code.TOO_MANY_TEST_SHARDS_OR_RUNS));
      }

      TestRunnerAction testAction =
          (TestRunnerAction)
              env.getSkyframeExecutor()
                  .getActionGraph(env.getReporter())
                  .getGeneratingAction(Iterables.getOnlyElement(statusArtifacts));
      TestTargetExecutionSettings settings = testAction.getExecutionSettings();
      // ensureRunfilesBuilt does build the runfiles, but an extra consistency check won't hurt.
      Preconditions.checkState(
          settings.getRunfilesSymlinksCreated()
              == options.getOptions(CoreOptions.class).buildRunfiles);

      ExecutionOptions executionOptions = options.getOptions(ExecutionOptions.class);
      Path tmpDirRoot =
          TestStrategy.getTmpRoot(env.getWorkspace(), env.getExecRoot(), executionOptions);
      PathFragment maybeRelativeTmpDir =
          tmpDirRoot.startsWith(env.getExecRoot())
              ? tmpDirRoot.relativeTo(env.getExecRoot())
              : tmpDirRoot.asFragment();
      Duration timeout =
          builtTargets
              .configuration
              .getFragment(TestConfiguration.class)
              .getTestTimeout()
              .get(testAction.getTestProperties().getTimeout());
      runEnvironment.putAll(
          testPolicy.computeTestEnvironment(
              testAction,
              env.getClientEnv(),
              timeout,
              settings.getRunfilesDir().relativeTo(env.getExecRoot()),
              maybeRelativeTmpDir.getRelative(TestStrategy.getTmpDirName(testAction))));
      workingDir = env.getExecRoot();

      try {
        testAction.prepare(
            env.getExecRoot(),
            ArtifactPathResolver.IDENTITY,
            /* bulkDeleter= */ null,
            /* cleanupArchivedArtifacts= */ false);
      } catch (IOException e) {
        throw new RunCommandException(
            reportAndCreateFailureResult(
                env,
                "Error while setting up test: " + e.getMessage(),
                Code.TEST_ENVIRONMENT_SETUP_FAILURE));
      } catch (InterruptedException e) {
        throw new RunCommandException(
            reportAndCreateFailureResult(
                env,
                "Error while setting up test: " + e.getMessage(),
                Code.TEST_ENVIRONMENT_SETUP_INTERRUPTED));
      }

      try {
        cmdLine.addAll(TestStrategy.getArgs(testAction));
        cmdLine.addAll(commandLineArgs);
        prettyCmdLine.addAll(cmdLine);
      } catch (ExecException e) {
        throw new RunCommandException(
            reportAndCreateFailureResult(
                env, Strings.nullToEmpty(e.getMessage()), Code.COMMAND_LINE_EXPANSION_FAILURE));
      } catch (InterruptedException e) {
        String message = "run: command line expansion interrupted";
        env.getReporter().handle(Event.error(message));
        throw new RunCommandException(
            BlazeCommandResult.detailedExitCode(
                InterruptedFailureDetails.detailedExitCode(message)));
      }
    } else {
      workingDir =
          builtTargets.targetToRunRunfilesDir != null
              ? builtTargets.targetToRunRunfilesDir
              : env.getWorkingDirectory();
      ActionEnvironment actionEnvironment = ActionEnvironment.EMPTY;
      if (builtTargets.targetToRunRunfilesSupport != null) {
        actionEnvironment = builtTargets.targetToRunRunfilesSupport.getActionEnvironment();
      }
      RunEnvironmentInfo environmentProvider =
          builtTargets.targetToRun.get(RunEnvironmentInfo.PROVIDER);
      if (environmentProvider != null) {
        actionEnvironment =
            actionEnvironment.withAdditionalVariables(
                environmentProvider.getEnvironment(),
                ImmutableSet.copyOf(environmentProvider.getInheritedEnvironment()));
      }
      actionEnvironment.resolve(runEnvironment, env.getClientEnv());
      try {
        List<String> args = computeArgs(builtTargets.targetToRun, commandLineArgs);
        constructCommandLine(
            cmdLine,
            prettyCmdLine,
            env,
            builtTargets.configuration,
            builtTargets.targetToRun,
            builtTargets.runUnderTarget,
            args);
      } catch (InterruptedException e) {
        String message = "run: command line expansion interrupted";
        env.getReporter().handle(Event.error(message));
        throw new RunCommandException(
            BlazeCommandResult.detailedExitCode(
                InterruptedFailureDetails.detailedExitCode(message)));
      } catch (CommandLineExpansionException e) {
        throw new RunCommandException(
            reportAndCreateFailureResult(
                env, Strings.nullToEmpty(e.getMessage()), Code.COMMAND_LINE_EXPANSION_FAILURE));
      }
    }

    return new RunCommandLine(
        ImmutableList.copyOf(cmdLine),
        ImmutableList.copyOf(prettyCmdLine),
        ImmutableSortedMap.copyOf(runEnvironment),
        workingDir);
  }

  private static void constructCommandLine(
      List<String> cmdLine,
      List<String> prettyCmdLine,
      CommandEnvironment env,
      BuildConfigurationValue configuration,
      ConfiguredTarget targetToRun,
      ConfiguredTarget runUnderTarget,
      List<String> args)
      throws RunCommandException {
    BlazeRuntime runtime = env.getRuntime();
    String productName = runtime.getProductName();
    Artifact executable = targetToRun.getProvider(FilesToRunProvider.class).getExecutable();

    BuildRequestOptions requestOptions = env.getOptions().getOptions(BuildRequestOptions.class);

    PathFragment executablePath = executable.getPath().asFragment();
    PathPrettyPrinter prettyPrinter =
        OutputDirectoryLinksUtils.getPathPrettyPrinter(
            runtime.getRuleClassProvider().getSymlinkDefinitions(),
            requestOptions.getSymlinkPrefix(productName),
            productName,
            env.getWorkspace(),
            requestOptions.printWorkspaceInOutputPathsIfNeeded
                ? env.getWorkingDirectory()
                : env.getWorkspace());
    PathFragment prettyExecutablePath =
        prettyPrinter.getPrettyPath(executable.getPath().asFragment());

    RunUnder runUnder = env.getOptions().getOptions(CoreOptions.class).runUnder;
    // Insert the command prefix specified by the "--run_under=<command-prefix>" option
    // at the start of the command line.
    if (runUnder != null) {
      String runUnderValue = runUnder.getValue();
      if (runUnderTarget != null) {
        // --run_under specifies a target. Get the corresponding executable.
        // This must be an absolute path, because the run_under target is only
        // in the runfiles of test targets.
        runUnderValue =
            runUnderTarget
                .getProvider(FilesToRunProvider.class)
                .getExecutable()
                .getPath()
                .getPathString();
        // If the run_under command contains any options, make sure to add them
        // to the command line as well.
        List<String> opts = runUnder.getOptions();
        if (!opts.isEmpty()) {
          runUnderValue += " " + ShellEscaper.escapeJoinAll(opts);
        }
      }

      PathFragment shellExecutable = ShToolchain.getPathForHost(configuration);
      if (shellExecutable.isEmpty()) {
        throw new RunCommandException(
            reportAndCreateFailureResult(
                env,
                "the \"run\" command needs a shell with \"--run_under\"; use the"
                    + " --shell_executable=<path> flag to specify its path, e.g."
                    + " --shell_executable=/bin/bash",
                Code.NO_SHELL_SPECIFIED));
      }

      cmdLine.add(shellExecutable.getPathString());
      cmdLine.add("-c");
      cmdLine.add(
          runUnderValue
              + " "
              + executablePath.getPathString()
              + " "
              + ShellEscaper.escapeJoinAll(args));
      prettyCmdLine.add(shellExecutable.getPathString());
      prettyCmdLine.add("-c");
      prettyCmdLine.add(
          runUnderValue
              + " "
              + prettyExecutablePath.getPathString()
              + " "
              + ShellEscaper.escapeJoinAll(args));
    } else {
      cmdLine.add(executablePath.getPathString());
      cmdLine.addAll(args);
      prettyCmdLine.add(prettyExecutablePath.getPathString());
      prettyCmdLine.addAll(args);
    }
  }

  private static ExecRequest buildExecRequest(
      CommandEnvironment env,
      Path workingDir,
      ImmutableList<String> args,
      ImmutableSortedMap<String, String> runEnv,
      ImmutableList<String> runEnvToClear,
      BuildConfigurationValue configuration)
      throws RunCommandException {
    ExecRequest.Builder execDescription =
        ExecRequest.newBuilder()
            .setWorkingDirectory(ByteString.copyFrom(workingDir.getPathString(), ISO_8859_1));

    if (OS.getCurrent() == OS.WINDOWS) {
      boolean isBinary = true;
      for (String arg : args) {
        if (!isBinary) {
          // All but the first element in `cmdLine` have to be escaped. The first element is the
          // binary, which must not be escaped.
          arg = ShellUtils.windowsEscapeArg(arg);
        }
        execDescription.addArgv(ByteString.copyFrom(arg, ISO_8859_1));
        isBinary = false;
      }
    } else {
      PathFragment shExecutable = ShToolchain.getPathForHost(configuration);
      if (shExecutable.isEmpty()) {
        throw new RunCommandException(
            reportAndCreateFailureResult(
                env,
                "the \"run\" command needs a shell with; use the --shell_executable=<path> "
                    + "flag to specify the shell's path, e.g. --shell_executable=/bin/bash",
                Code.NO_SHELL_SPECIFIED));
      }

      String shellEscaped = ShellEscaper.escapeJoinAll(args);
      if (OS.getCurrent() == OS.WINDOWS) {
        // On Windows, we run Bash as a subprocess of the client (via CreateProcessW).
        // Bash uses its own (Bash-style) flag parsing logic, not the default logic for which
        // ShellUtils.windowsEscapeArg escapes, so we escape the flags once again Bash-style.
        shellEscaped = "\"" + shellEscaped.replace("\\", "\\\\").replace("\"", "\\\"") + "\"";
      }

      ImmutableList<String> shellCmdLine =
          ImmutableList.<String>of(shExecutable.getPathString(), "-c", shellEscaped);

      for (String arg : shellCmdLine) {
        execDescription.addArgv(ByteString.copyFrom(arg, ISO_8859_1));
      }
    }

    for (Map.Entry<String, String> variable : runEnv.entrySet()) {
      execDescription.addEnvironmentVariable(
          EnvironmentVariable.newBuilder()
              .setName(ByteString.copyFrom(variable.getKey(), ISO_8859_1))
              .setValue(ByteString.copyFrom(variable.getValue(), ISO_8859_1))
              .build());
    }
    execDescription.addAllEnvironmentVariableToClear(
        runEnvToClear.stream()
            .map(s -> ByteString.copyFrom(s, ISO_8859_1))
            .collect(toImmutableList()));
    return execDescription.build();
  }

  private static class RunCommandException extends Exception {
    private final BlazeCommandResult result;

    private RunCommandException(BlazeCommandResult result) {
      Preconditions.checkArgument(!result.isSuccess(), "Success is not exceptional: %s", result);
      this.result = result;
    }
  }

  /** Contains the targets built as part of a run-command invocation. */
  private static class BuiltTargets {
    private final ConfiguredTarget targetToRun;
    private final Path targetToRunRunfilesDir;
    private final RunfilesSupport targetToRunRunfilesSupport;
    @Nullable private final ConfiguredTarget runUnderTarget;
    private final BuildConfigurationValue configuration;

    private BuiltTargets(
        ConfiguredTarget targetToRun,
        Path targetToRunRunfilesDir,
        RunfilesSupport targetToRunRunfilesSupport,
        @Nullable ConfiguredTarget runUnderTarget,
        BuildConfigurationValue configuration) {
      this.targetToRun = targetToRun;
      this.runUnderTarget = runUnderTarget;
      this.targetToRunRunfilesDir = targetToRunRunfilesDir;
      this.targetToRunRunfilesSupport = targetToRunRunfilesSupport;
      this.configuration = configuration;
    }
  }

  /**
   * When using an output service (e.g. Build without the Bytes), flushes the output tree, waiting
   * for downloads to complete. This is necessary since outputs might still be downloading in the
   * background.
   */
  private static void flushOutputs(CommandEnvironment env) {
    if (env.getOutputService() != null) {
      try {
        env.getOutputService().flushOutputTree();
      } catch (InterruptedException ignored) {
        Thread.currentThread().interrupt();
      }
    }
  }

  private static BlazeCommandResult reportAndCreateFailureResult(
      CommandEnvironment env, String message, Code detailedCode) {
    env.getReporter().handle(Event.error(message));
    return BlazeCommandResult.failureDetail(createFailureDetail(message, detailedCode));
  }

  /**
   * Ensures that runfiles are built for the specified target. If they already are, does nothing,
   * otherwise builds them.
   */
  private static Path ensureRunfilesBuilt(
      CommandEnvironment env,
      RunfilesSupport runfilesSupport,
      BuildConfigurationValue configuration)
      throws RunfilesException, InterruptedException {
    Artifact manifest = Preconditions.checkNotNull(runfilesSupport.getRunfilesManifest());
    PathFragment runfilesDir = runfilesSupport.getRunfilesDirectoryExecPath();
    Path workingDir = env.getExecRoot().getRelative(runfilesDir);
    // On Windows, runfiles tree is disabled.
    // Workspace name directory doesn't exist, so don't add it.
    if (configuration.runfilesEnabled()) {
      workingDir = workingDir.getRelative(runfilesSupport.getRunfiles().getSuffix());
    }

    // Always create runfiles directory and the workspace-named directory underneath, even if we
    // run with --enable_runfiles=no (which is the default on Windows as of 2020-01-24).
    // If the binary we run is in fact a test, it will expect to be able to chdir into the runfiles
    // directory. See https://github.com/bazelbuild/bazel/issues/10621
    try {
      runfilesSupport
          .getRunfilesDirectory()
          .getRelative(runfilesSupport.getWorkspaceName())
          .createDirectoryAndParents();
    } catch (IOException e) {
      throw new RunfilesException(
          "Failed to create runfiles directories: " + e.getMessage(),
          Code.RUNFILES_DIRECTORIES_CREATION_FAILURE,
          e);
    }

    // When runfiles are not generated, getManifest() returns the
    // .runfiles_manifest file, otherwise it returns the MANIFEST file. This is
    // a handy way to check whether runfiles were built or not.
    if (!RUNFILES_MANIFEST.matches(manifest.getFilename())) {
      return workingDir;
    }

    SymlinkTreeHelper helper =
        new SymlinkTreeHelper(manifest.getPath(), runfilesSupport.getRunfilesDirectory(), false);
    try {
      helper.createSymlinksUsingCommand(
          env.getExecRoot(),
          env.getBlazeWorkspace().getBinTools(),
          /* shellEnvironment= */ ImmutableMap.of(),
          /* outErr= */ null);
    } catch (EnvironmentalExecException e) {
      throw new RunfilesException(
          "Failed to create runfiles symlinks: " + e.getMessage(),
          Code.RUNFILES_SYMLINKS_CREATION_FAILURE,
          e);
    }
    return workingDir;
  }

  private static void writeScript(
      CommandEnvironment env, PathFragment shellExecutable, PathFragment scriptPathFrag, String cmd)
      throws IOException {
    Path scriptPath = env.getWorkingDirectory().getRelative(scriptPathFrag);
    if (OS.getCurrent() == OS.WINDOWS) {
      FileSystemUtils.writeContent(scriptPath, ISO_8859_1, "@echo off\n" + cmd + " %*");
      scriptPath.setExecutable(true);
    } else {
      FileSystemUtils.writeContent(
          scriptPath, ISO_8859_1, "#!" + shellExecutable.getPathString() + "\n" + cmd + " \"$@\"");
      scriptPath.setExecutable(true);
    }
  }

  // Make sure we are building exactly 1 binary target.
  // If keepGoing, we'll build all the targets even if they are non-binary.
  private static void validateTargets(
      Reporter reporter,
      List<String> targetPatternStrings,
      Collection<Target> targets,
      RunUnder runUnder,
      boolean keepGoing)
      throws LoadingFailedException {
    Target targetToRun = null;
    Target runUnderTarget = null;

    boolean singleTargetWarningWasOutput = false;
    int maxTargets = runUnder != null && runUnder.getLabel() != null ? 2 : 1;
    if (targets.size() > maxTargets) {
      warningOrException(
          reporter,
          makeErrorMessageForNotHavingASingleTarget(
              targetPatternStrings.get(0),
              Iterables.transform(targets, t -> t.getLabel().toString())),
          keepGoing,
          Code.TOO_MANY_TARGETS_SPECIFIED);
      singleTargetWarningWasOutput = true;
    }
    for (Target target : targets) {
      if (!isExecutable(target)) {
        warningOrException(
            reporter, notExecutableError(target), keepGoing, Code.TARGET_NOT_EXECUTABLE);
      }

      if (runUnder != null && target.getLabel().equals(runUnder.getLabel())) {
        // It's impossible to have two targets with the same label.
        Preconditions.checkState(runUnderTarget == null);
        runUnderTarget = target;
      } else if (targetToRun == null) {
        targetToRun = target;
      } else {
        if (!singleTargetWarningWasOutput) {
          warningOrException(
              reporter,
              makeErrorMessageForNotHavingASingleTarget(
                  targetPatternStrings.get(0),
                  Iterables.transform(targets, t -> t.getLabel().toString())),
              keepGoing,
              Code.TOO_MANY_TARGETS_SPECIFIED);
        }
        return;
      }
    }
    // Handle target & run_under referring to the same target.
    if ((targetToRun == null) && (runUnderTarget != null)) {
      targetToRun = runUnderTarget;
    }
    if (targetToRun == null) {
      warningOrException(reporter, NO_TARGET_MESSAGE, keepGoing, Code.NO_TARGET_SPECIFIED);
    }
  }

  /**
   * If keepGoing, print a warning and return the given collection. Otherwise, throw
   * InvalidTargetException.
   */
  private static void warningOrException(
      Reporter reporter, String message, boolean keepGoing, Code detailedCode)
      throws LoadingFailedException {
    if (keepGoing) {
      reporter.handle(Event.warn(message + ". Will continue anyway"));
    } else {
      throw new LoadingFailedException(
          message, DetailedExitCode.of(createFailureDetail(message, detailedCode)));
    }
  }

  private static String notExecutableError(Target target) {
    return "Cannot run target " + target.getLabel() + ": Not executable";
  }

  /**
   * Performs all available validation checks on an individual target.
   *
   * @param configuredTarget ConfiguredTarget to validate
   * @return BlazeCommandResult.exitCode(ExitCode.SUCCESS) if all checks succeeded, otherwise a
   *     result describing the failure.
   * @throws IllegalStateException if unable to find a target from the package manager.
   */
  private static BlazeCommandResult fullyValidateTarget(
      CommandEnvironment env, ConfiguredTarget configuredTarget) {

    Target target;
    try {
      target = env.getPackageManager().getTarget(env.getReporter(), configuredTarget.getLabel());
    } catch (InterruptedException e) {
      String message = "run command interrupted";
      env.getReporter().handle(Event.error(message));
      return BlazeCommandResult.detailedExitCode(
          InterruptedFailureDetails.detailedExitCode(message));
    } catch (NoSuchTargetException | NoSuchPackageException e) {
      env.getReporter().handle(Event.error("Failed to find a target to validate. " + e));
      throw new IllegalStateException("Failed to find a target to validate", e);
    }

    if (!isExecutable(target)) {
      return reportAndCreateFailureResult(
          env, notExecutableError(target), Code.TARGET_NOT_EXECUTABLE);
    }

    Artifact executable =
        Preconditions.checkNotNull(
                configuredTarget.getProvider(FilesToRunProvider.class), configuredTarget)
            .getExecutable();
    if (executable == null) {
      return reportAndCreateFailureResult(
          env, notExecutableError(target), Code.TARGET_NOT_EXECUTABLE);
    }

    Path executablePath = executable.getPath();
    try {
      if (!executablePath.exists() || !executablePath.isExecutable()) {
        return reportAndCreateFailureResult(
            env,
            "Non-existent or non-executable " + executablePath,
            Code.TARGET_BUILT_BUT_PATH_NOT_EXECUTABLE);
      }
    } catch (IOException e) {
      return reportAndCreateFailureResult(
          env,
          "Error checking " + executablePath.getPathString() + ": " + e.getMessage(),
          Code.TARGET_BUILT_BUT_PATH_VALIDATION_FAILED);
    }

    return BlazeCommandResult.success();
  }

  /**
   * Return true iff it is possible that {@code target} is a rule that has an executable file. This
   * *_test rules, *_binary rules, aliases, generated outputs, and inputs.
   *
   * <p>Determining definitively whether a rule produces an executable can only be done after
   * analysis. This is only an early check to quickly catch most mistakes.
   */
  private static boolean isExecutable(Target target) {
    return isPlainFile(target)
        || isExecutableNonTestRule(target)
        || TargetUtils.isTestRule(target)
        || AliasProvider.mayBeAlias(target);
  }

  /**
   * Return true iff {@code target} is a rule that generates an executable file and is user-executed
   * code.
   */
  private static boolean isExecutableNonTestRule(Target target) {
    if (!(target instanceof Rule)) {
      return false;
    }
    Rule rule = ((Rule) target);
    if (rule.getRuleClassObject().hasAttr("$is_executable", Type.BOOLEAN)) {
      return NonconfigurableAttributeMapper.of(rule).get("$is_executable", Type.BOOLEAN);
    }
    return false;
  }

  private static boolean isPlainFile(Target target) {
    return (target instanceof OutputFile) || (target instanceof InputFile);
  }

  private static String makeErrorMessageForNotHavingASingleTarget(
      String targetPatternString, Iterable<String> expandedTargetNames) {
    final int maxNumExpandedTargetsToIncludeInErrorMessage = 5;
    boolean truncateTargetNameList = Iterables.size(expandedTargetNames) > 5;
    Iterable<String> targetNamesToIncludeInErrorMessage =
        truncateTargetNameList
            ? Iterables.limit(expandedTargetNames, maxNumExpandedTargetsToIncludeInErrorMessage)
            : expandedTargetNames;
    return String.format(
        "Only a single target can be run. Your target pattern %s expanded to the targets %s%s",
        targetPatternString,
        Joiner.on(", ").join(ImmutableSortedSet.copyOf(targetNamesToIncludeInErrorMessage)),
        truncateTargetNameList ? "[TRUNCATED]" : "");
  }

  private static FailureDetail createFailureDetail(String message, Code detailedCode) {
    return FailureDetail.newBuilder()
        .setMessage(message)
        .setRunCommand(FailureDetails.RunCommand.newBuilder().setCode(detailedCode))
        .build();
  }

  private static class RunfilesException extends Exception {
    private final FailureDetails.RunCommand.Code detailedCode;

    private RunfilesException(String message, Code detailedCode, Exception cause) {
      super("Error creating runfiles: " + message, cause);
      this.detailedCode = detailedCode;
    }

    private FailureDetail createFailureDetail() {
      return RunCommand.createFailureDetail(getMessage(), detailedCode);
    }
  }
}