Revert "Revert "Use native async/await support in pub.""

sdk/lib/_internal/pub_generated/lib/src/entrypoint.dart

Index: sdk/lib/_internal/pub_generated/lib/src/entrypoint.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/entrypoint.dart b/sdk/lib/_internal/pub_generated/lib/src/entrypoint.dart
deleted file mode 100644
index 2ae51dc7b12b9c5aaf1ba6ef165cd33c48926c55..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/lib/src/entrypoint.dart
+++ /dev/null
@@ -1,951 +0,0 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-library pub.entrypoint;
-
-import 'dart:async';
-
-import 'package:path/path.dart' as path;
-import 'package:barback/barback.dart';
-
-import 'barback/asset_environment.dart';
-import 'io.dart';
-import 'lock_file.dart';
-import 'log.dart' as log;
-import 'package.dart';
-import 'package_graph.dart';
-import 'sdk.dart' as sdk;
-import 'solver/version_solver.dart';
-import 'source/cached.dart';
-import 'system_cache.dart';
-import 'utils.dart';
-
-/// The context surrounding the root package pub is operating on.
-///
-/// Pub operates over a directed graph of dependencies that starts at a root
-/// "entrypoint" package. This is typically the package where the current
-/// working directory is located. An entrypoint knows the [root] package it is
-/// associated with and is responsible for managing the "packages" directory
-/// for it.
-///
-/// That directory contains symlinks to all packages used by an app. These links
-/// point either to the [SystemCache] or to some other location on the local
-/// filesystem.
-///
-/// While entrypoints are typically applications, a pure library package may end
-/// up being used as an entrypoint. Also, a single package may be used as an
-/// entrypoint in one context but not in another. For example, a package that
-/// contains a reusable library may not be the entrypoint when used by an app,
-/// but may be the entrypoint when you're running its tests.
-class Entrypoint {
-  /// The root package this entrypoint is associated with.
-  final Package root;
-
-  /// The system-wide cache which caches packages that need to be fetched over
-  /// the network.
-  final SystemCache cache;
-
-  /// Whether to create and symlink a "packages" directory containing links to
-  /// the installed packages.
-  final bool _packageSymlinks;
-
-  /// The lockfile for the entrypoint.
-  ///
-  /// If not provided to the entrypoint, it will be laoded lazily from disc.
-  LockFile _lockFile;
-
-  /// The graph of all packages reachable from the entrypoint.
-  PackageGraph _packageGraph;
-
-  /// Loads the entrypoint from a package at [rootDir].
-  ///
-  /// If [packageSymlinks] is `true`, this will create a "packages" directory
-  /// with symlinks to the installed packages. This directory will be symlinked
-  /// into any directory that might contain an entrypoint.
-  Entrypoint(String rootDir, SystemCache cache, {bool packageSymlinks: true})
-      : root = new Package.load(null, rootDir, cache.sources),
-        cache = cache,
-        _packageSymlinks = packageSymlinks;
-
-  /// Creates an entrypoint given package and lockfile objects.
-  Entrypoint.inMemory(this.root, this._lockFile, this.cache)
-      : _packageSymlinks = false;
-
-  /// The path to the entrypoint's "packages" directory.
-  String get packagesDir => root.path('packages');
-
-  /// `true` if the entrypoint package currently has a lock file.
-  bool get lockFileExists => _lockFile != null || entryExists(lockFilePath);
-
-  LockFile get lockFile {
-    if (_lockFile != null) return _lockFile;
-
-    if (!lockFileExists) {
-      _lockFile = new LockFile.empty();
-    } else {
-      _lockFile = new LockFile.load(lockFilePath, cache.sources);
-    }
-
-    return _lockFile;
-  }
-
-  /// The path to the entrypoint package's pubspec.
-  String get pubspecPath => root.path('pubspec.yaml');
-
-  /// The path to the entrypoint package's lockfile.
-  String get lockFilePath => root.path('pubspec.lock');
-
-  /// Gets all dependencies of the [root] package.
-  ///
-  /// Performs version resolution according to [SolveType].
-  ///
-  /// [useLatest], if provided, defines a list of packages that will be
-  /// unlocked and forced to their latest versions. If [upgradeAll] is
-  /// true, the previous lockfile is ignored and all packages are re-resolved
-  /// from scratch. Otherwise, it will attempt to preserve the versions of all
-  /// previously locked packages.
-  ///
-  /// Shows a report of the changes made relative to the previous lockfile. If
-  /// this is an upgrade or downgrade, all transitive dependencies are shown in
-  /// the report. Otherwise, only dependencies that were changed are shown. If
-  /// [dryRun] is `true`, no physical changes are made.
-  Future acquireDependencies(SolveType type, {List<String> useLatest,
-      bool dryRun: false}) {
-    final completer0 = new Completer();
-    scheduleMicrotask(() {
-      try {
-        new Future.value(
-            resolveVersions(
-                type,
-                cache.sources,
-                root,
-                lockFile: lockFile,
-                useLatest: useLatest)).then((x0) {
-          try {
-            var result = x0;
-            join0() {
-              result.showReport(type);
-              join1() {
-                join2() {
-                  new Future.value(
-                      Future.wait(result.packages.map(_get))).then((x1) {
-                    try {
-                      var ids = x1;
-                      _saveLockFile(ids);
-                      join3() {
-                        _linkOrDeleteSecondaryPackageDirs();
-                        result.summarizeChanges(type, dryRun: dryRun);
-                        new Future.value(loadPackageGraph(result)).then((x2) {
-                          try {
-                            var packageGraph = x2;
-                            packageGraph.loadTransformerCache().clearIfOutdated(
-                                result.changedPackages);
-                            join4() {
-                              completer0.complete();
-                            }
-                            catch0(error, stackTrace) {
-                              try {
-                                log.exception(error, stackTrace);
-                                join4();
-                              } catch (error, stackTrace) {
-                                completer0.completeError(error, stackTrace);
-                              }
-                            }
-                            try {
-                              new Future.value(
-                                  precompileDependencies(changed: result.changedPackages)).then((x3) {
-                                try {
-                                  x3;
-                                  new Future.value(
-                                      precompileExecutables(changed: result.changedPackages)).then((x4) {
-                                    try {
-                                      x4;
-                                      join4();
-                                    } catch (e0, s0) {
-                                      catch0(e0, s0);
-                                    }
-                                  }, onError: catch0);
-                                } catch (e1, s1) {
-                                  catch0(e1, s1);
-                                }
-                              }, onError: catch0);
-                            } catch (e2, s2) {
-                              catch0(e2, s2);
-                            }
-                          } catch (e3, s3) {
-                            completer0.completeError(e3, s3);
-                          }
-                        }, onError: completer0.completeError);
-                      }
-                      if (_packageSymlinks) {
-                        _linkSelf();
-                        join3();
-                      } else {
-                        join3();
-                      }
-                    } catch (e4, s4) {
-                      completer0.completeError(e4, s4);
-                    }
-                  }, onError: completer0.completeError);
-                }
-                if (_packageSymlinks) {
-                  cleanDir(packagesDir);
-                  join2();
-                } else {
-                  deleteEntry(packagesDir);
-                  join2();
-                }
-              }
-              if (dryRun) {
-                result.summarizeChanges(type, dryRun: dryRun);
-                completer0.complete(null);
-              } else {
-                join1();
-              }
-            }
-            if (!result.succeeded) {
-              throw result.error;
-              join0();
-            } else {
-              join0();
-            }
-          } catch (e5, s5) {
-            completer0.completeError(e5, s5);
-          }
-        }, onError: completer0.completeError);
-      } catch (e, s) {
-        completer0.completeError(e, s);
-      }
-    });
-    return completer0.future;
-  }
-
-  /// Precompile any transformed dependencies of the entrypoint.
-  ///
-  /// If [changed] is passed, only dependencies whose contents might be changed
-  /// if one of the given packages changes will be recompiled.
-  Future precompileDependencies({Iterable<String> changed}) {
-    final completer0 = new Completer();
-    scheduleMicrotask(() {
-      try {
-        join0() {
-          new Future.value(loadPackageGraph()).then((x0) {
-            try {
-              var graph = x0;
-              var depsDir = path.join('.pub', 'deps', 'debug');
-              var dependenciesToPrecompile =
-                  graph.packages.values.where(((package) {
-                if (package.pubspec.transformers.isEmpty) return false;
-                if (graph.isPackageMutable(package.name)) return false;
-                if (!dirExists(path.join(depsDir, package.name))) return true;
-                if (changed == null) return true;
-                return overlaps(
-                    graph.transitiveDependencies(
-                        package.name).map((package) => package.name).toSet(),
-                    changed);
-              })).map(((package) {
-                return package.name;
-              })).toSet();
-              join1() {
-                join2() {
-                  join3() {
-                    completer0.complete();
-                  }
-                  catch0(_, s0) {
-                    try {
-                      var it0 = dependenciesToPrecompile.iterator;
-                      break0() {
-                        completer0.completeError(_, s0);
-                      }
-                      var trampoline0;
-                      continue0() {
-                        trampoline0 = null;
-                        if (it0.moveNext()) {
-                          var package = it0.current;
-                          deleteEntry(path.join(depsDir, package));
-                          trampoline0 = continue0;
-                          do trampoline0(); while (trampoline0 != null);
-                        } else {
-                          break0();
-                        }
-                      }
-                      trampoline0 = continue0;
-                      do trampoline0(); while (trampoline0 != null);
-                    } catch (_, s0) {
-                      completer0.completeError(_, s0);
-                    }
-                  }
-                  try {
-                    new Future.value(
-                        log.progress("Precompiling dependencies", (() {
-                      final completer0 = new Completer();
-                      scheduleMicrotask(() {
-                        try {
-                          var packagesToLoad = unionAll(
-                              dependenciesToPrecompile.map(graph.transitiveDependencies)).map(((package) {
-                            return package.name;
-                          })).toSet();
-                          new Future.value(
-                              AssetEnvironment.create(
-                                  this,
-                                  BarbackMode.DEBUG,
-                                  packages: packagesToLoad,
-                                  useDart2JS: false)).then((x0) {
-                            try {
-                              var environment = x0;
-                              environment.barback.errors.listen(((_) {
-                              }));
-                              new Future.value(
-                                  environment.barback.getAllAssets()).then((x1) {
-                                try {
-                                  var assets = x1;
-                                  new Future.value(
-                                      waitAndPrintErrors(assets.map(((asset) {
-                                    final completer0 = new Completer();
-                                    scheduleMicrotask(() {
-                                      try {
-                                        join0() {
-                                          var destPath =
-                                              path.join(depsDir, asset.id.package, path.fromUri(asset.id.path));
-                                          ensureDir(path.dirname(destPath));
-                                          new Future.value(
-                                              createFileFromStream(asset.read(), destPath)).then((x0) {
-                                            try {
-                                              x0;
-                                              completer0.complete();
-                                            } catch (e0, s0) {
-                                              completer0.completeError(e0, s0);
-                                            }
-                                          }, onError: completer0.completeError);
-                                        }
-                                        if (!dependenciesToPrecompile.contains(
-                                            asset.id.package)) {
-                                          completer0.complete(null);
-                                        } else {
-                                          join0();
-                                        }
-                                      } catch (e, s) {
-                                        completer0.completeError(e, s);
-                                      }
-                                    });
-                                    return completer0.future;
-                                  })))).then((x2) {
-                                    try {
-                                      x2;
-                                      log.message(
-                                          "Precompiled " +
-                                              toSentence(ordered(dependenciesToPrecompile).map(log.bold)) +
-                                              ".");
-                                      completer0.complete();
-                                    } catch (e0, s0) {
-                                      completer0.completeError(e0, s0);
-                                    }
-                                  }, onError: completer0.completeError);
-                                } catch (e1, s1) {
-                                  completer0.completeError(e1, s1);
-                                }
-                              }, onError: completer0.completeError);
-                            } catch (e2, s2) {
-                              completer0.completeError(e2, s2);
-                            }
-                          }, onError: completer0.completeError);
-                        } catch (e, s) {
-                          completer0.completeError(e, s);
-                        }
-                      });
-                      return completer0.future;
-                    }))).then((x1) {
-                      try {
-                        x1;
-                        join3();
-                      } catch (e0, s1) {
-                        catch0(e0, s1);
-                      }
-                    }, onError: catch0);
-                  } catch (e1, s2) {
-                    catch0(e1, s2);
-                  }
-                }
-                if (dependenciesToPrecompile.isEmpty) {
-                  completer0.complete(null);
-                } else {
-                  join2();
-                }
-              }
-              if (dirExists(depsDir)) {
-                var it1 = dependenciesToPrecompile.iterator;
-                break1() {
-                  var it2 = listDir(depsDir).iterator;
-                  break2() {
-                    join1();
-                  }
-                  var trampoline2;
-                  continue2() {
-                    trampoline2 = null;
-                    if (it2.moveNext()) {
-                      var subdir = it2.current;
-                      var package = graph.packages[path.basename(subdir)];
-                      join4() {
-                        trampoline2 = continue2;
-                        do trampoline2(); while (trampoline2 != null);
-                      }
-                      if (package == null ||
-                          package.pubspec.transformers.isEmpty ||
-                          graph.isPackageMutable(package.name)) {
-                        deleteEntry(subdir);
-                        join4();
-                      } else {
-                        join4();
-                      }
-                    } else {
-                      break2();
-                    }
-                  }
-                  trampoline2 = continue2;
-                  do trampoline2(); while (trampoline2 != null);
-                }
-                var trampoline1;
-                continue1() {
-                  trampoline1 = null;
-                  if (it1.moveNext()) {
-                    var package = it1.current;
-                    deleteEntry(path.join(depsDir, package));
-                    trampoline1 = continue1;
-                    do trampoline1(); while (trampoline1 != null);
-                  } else {
-                    break1();
-                  }
-                }
-                trampoline1 = continue1;
-                do trampoline1(); while (trampoline1 != null);
-              } else {
-                join1();
-              }
-            } catch (e2, s3) {
-              completer0.completeError(e2, s3);
-            }
-          }, onError: completer0.completeError);
-        }
-        if (changed != null) {
-          changed = changed.toSet();
-          join0();
-        } else {
-          join0();
-        }
-      } catch (e, s) {
-        completer0.completeError(e, s);
-      }
-    });
-    return completer0.future;
-  }
-
-  /// Precompiles all executables from dependencies that don't transitively
-  /// depend on [this] or on a path dependency.
-  Future precompileExecutables({Iterable<String> changed}) {
-    final completer0 = new Completer();
-    scheduleMicrotask(() {
-      try {
-        join0() {
-          var binDir = path.join('.pub', 'bin');
-          var sdkVersionPath = path.join(binDir, 'sdk-version');
-          var sdkMatches =
-              fileExists(sdkVersionPath) &&
-              readTextFile(sdkVersionPath) == "${sdk.version}\n";
-          join1() {
-            new Future.value(loadPackageGraph()).then((x0) {
-              try {
-                var graph = x0;
-                var executables =
-                    new Map.fromIterable(root.immediateDependencies, key: ((dep) {
-                  return dep.name;
-                }), value: ((dep) {
-                  return _executablesForPackage(graph, dep.name, changed);
-                }));
-                var it0 = executables.keys.toList().iterator;
-                break0() {
-                  join2() {
-                    join3() {
-                      new Future.value(
-                          log.progress("Precompiling executables", (() {
-                        final completer0 = new Completer();
-                        scheduleMicrotask(() {
-                          try {
-                            ensureDir(binDir);
-                            writeTextFile(sdkVersionPath, "${sdk.version}\n");
-                            var packagesToLoad =
-                                unionAll(executables.keys.map(graph.transitiveDependencies)).map(((package) {
-                              return package.name;
-                            })).toSet();
-                            var executableIds =
-                                unionAll(executables.values.map(((ids) {
-                              return ids.toSet();
-                            })));
-                            new Future.value(
-                                AssetEnvironment.create(
-                                    this,
-                                    BarbackMode.RELEASE,
-                                    packages: packagesToLoad,
-                                    entrypoints: executableIds,
-                                    useDart2JS: false)).then((x0) {
-                              try {
-                                var environment = x0;
-                                environment.barback.errors.listen(((error) {
-                                  log.error(log.red("Build error:\n$error"));
-                                }));
-                                new Future.value(
-                                    waitAndPrintErrors(executables.keys.map(((package) {
-                                  final completer0 = new Completer();
-                                  scheduleMicrotask(() {
-                                    try {
-                                      var dir = path.join(binDir, package);
-                                      cleanDir(dir);
-                                      new Future.value(
-                                          environment.precompileExecutables(
-                                              package,
-                                              dir,
-                                              executableIds: executables[package])).then((x0) {
-                                        try {
-                                          x0;
-                                          completer0.complete();
-                                        } catch (e0, s0) {
-                                          completer0.completeError(e0, s0);
-                                        }
-                                      }, onError: completer0.completeError);
-                                    } catch (e, s) {
-                                      completer0.completeError(e, s);
-                                    }
-                                  });
-                                  return completer0.future;
-                                })))).then((x1) {
-                                  try {
-                                    x1;
-                                    completer0.complete();
-                                  } catch (e0, s0) {
-                                    completer0.completeError(e0, s0);
-                                  }
-                                }, onError: completer0.completeError);
-                              } catch (e1, s1) {
-                                completer0.completeError(e1, s1);
-                              }
-                            }, onError: completer0.completeError);
-                          } catch (e, s) {
-                            completer0.completeError(e, s);
-                          }
-                        });
-                        return completer0.future;
-                      }))).then((x1) {
-                        try {
-                          x1;
-                          completer0.complete();
-                        } catch (e0, s0) {
-                          completer0.completeError(e0, s0);
-                        }
-                      }, onError: completer0.completeError);
-                    }
-                    if (executables.isEmpty) {
-                      completer0.complete(null);
-                    } else {
-                      join3();
-                    }
-                  }
-                  if (!sdkMatches) {
-                    deleteEntry(binDir);
-                    join2();
-                  } else {
-                    join2();
-                  }
-                }
-                var trampoline0;
-                continue0() {
-                  trampoline0 = null;
-                  if (it0.moveNext()) {
-                    var package = it0.current;
-                    join4() {
-                      trampoline0 = continue0;
-                      do trampoline0(); while (trampoline0 != null);
-                    }
-                    if (executables[package].isEmpty) {
-                      executables.remove(package);
-                      join4();
-                    } else {
-                      join4();
-                    }
-                  } else {
-                    break0();
-                  }
-                }
-                trampoline0 = continue0;
-                do trampoline0(); while (trampoline0 != null);
-              } catch (e1, s1) {
-                completer0.completeError(e1, s1);
-              }
-            }, onError: completer0.completeError);
-          }
-          if (!sdkMatches) {
-            changed = null;
-            join1();
-          } else {
-            join1();
-          }
-        }
-        if (changed != null) {
-          changed = changed.toSet();
-          join0();
-        } else {
-          join0();
-        }
-      } catch (e, s) {
-        completer0.completeError(e, s);
-      }
-    });
-    return completer0.future;
-  }
-
-  /// Returns the list of all executable assets for [packageName] that should be
-  /// precompiled.
-  ///
-  /// If [changed] isn't `null`, executables for [packageName] will only be
-  /// compiled if they might depend on a package in [changed].
-  List<AssetId> _executablesForPackage(PackageGraph graph, String packageName,
-      Set<String> changed) {
-    var package = graph.packages[packageName];
-    var binDir = package.path('bin');
-    if (!dirExists(binDir)) return [];
-    if (graph.isPackageMutable(packageName)) return [];
-
-    var executables = package.executableIds;
-
-    // If we don't know which packages were changed, always precompile the
-    // executables.
-    if (changed == null) return executables;
-
-    // If any of the package's dependencies changed, recompile the executables.
-    if (graph.transitiveDependencies(
-        packageName).any((package) => changed.contains(package.name))) {
-      return executables;
-    }
-
-    // If any executables doesn't exist, precompile them regardless of what
-    // changed. Since we delete the bin directory before recompiling, we need to
-    // recompile all executables.
-    var executablesExist = executables.every(
-        (executable) =>
-            fileExists(
-                path.join(
-                    '.pub',
-                    'bin',
-                    packageName,
-                    "${path.url.basename(executable.path)}.snapshot")));
-    if (!executablesExist) return executables;
-
-    // Otherwise, we don't need to recompile.
-    return [];
-  }
-
-  /// Makes sure the package at [id] is locally available.
-  ///
-  /// This automatically downloads the package to the system-wide cache as well
-  /// if it requires network access to retrieve (specifically, if the package's
-  /// source is a [CachedSource]).
-  Future<PackageId> _get(PackageId id) {
-    if (id.isRoot) return new Future.value(id);
-
-    var source = cache.sources[id.source];
-    return new Future.sync(() {
-      if (!_packageSymlinks) {
-        if (source is! CachedSource) return null;
-        return source.downloadToSystemCache(id);
-      }
-
-      var packageDir = path.join(packagesDir, id.name);
-      if (entryExists(packageDir)) deleteEntry(packageDir);
-      return source.get(id, packageDir);
-    }).then((_) => source.resolveId(id));
-  }
-
-  /// Determines whether or not the lockfile is out of date with respect to the
-  /// pubspec.
-  ///
-  /// This will be `false` if there is no lockfile at all, or if the pubspec
-  /// contains dependencies that are not in the lockfile or that don't match
-  /// what's in there.
-  bool _isLockFileUpToDate(LockFile lockFile) {
-    /// If this is an entrypoint for an in-memory package, trust the in-memory
-    /// lockfile provided for it.
-    if (root.dir == null) return true;
-
-    return root.immediateDependencies.every((package) {
-      var locked = lockFile.packages[package.name];
-      if (locked == null) return false;
-
-      if (package.source != locked.source) return false;
-      if (!package.constraint.allows(locked.version)) return false;
-
-      var source = cache.sources[package.source];
-      if (source == null) return false;
-
-      return source.descriptionsEqual(package.description, locked.description);
-    });
-  }
-
-  /// Determines whether all of the packages in the lockfile are already
-  /// installed and available.
-  ///
-  /// Note: this assumes [isLockFileUpToDate] has already been called and
-  /// returned `true`.
-  Future<bool> _arePackagesAvailable(LockFile lockFile) {
-    return Future.wait(lockFile.packages.values.map((package) {
-      var source = cache.sources[package.source];
-
-      // This should only be called after [_isLockFileUpToDate] has returned
-      // `true`, which ensures all of the sources in the lock file are valid.
-      assert(source != null);
-
-      // We only care about cached sources. Uncached sources aren't "installed".
-      // If one of those is missing, we want to show the user the file not
-      // found error later since installing won't accomplish anything.
-      if (source is! CachedSource) return new Future.value(true);
-
-      // Get the directory.
-      return source.getDirectory(package).then((dir) {
-        // See if the directory is there and looks like a package.
-        return dirExists(dir) || fileExists(path.join(dir, "pubspec.yaml"));
-      });
-    })).then((results) {
-      // Make sure they are all true.
-      return results.every((result) => result);
-    });
-  }
-
-  /// Gets dependencies if the lockfile is out of date with respect to the
-  /// pubspec.
-  Future ensureLockFileIsUpToDate() {
-    return new Future.sync(() {
-      // If we don't have a current lock file, we definitely need to install.
-      if (!_isLockFileUpToDate(lockFile)) {
-        if (lockFileExists) {
-          log.message(
-              "Your pubspec has changed, so we need to update your lockfile:");
-        } else {
-          log.message(
-              "You don't have a lockfile, so we need to generate that:");
-        }
-
-        return false;
-      }
-
-      // If we do have a lock file, we still need to make sure the packages
-      // are actually installed. The user may have just gotten a package that
-      // includes a lockfile.
-      return _arePackagesAvailable(lockFile).then((available) {
-        if (!available) {
-          log.message(
-              "You are missing some dependencies, so we need to install them " "first:");
-        }
-
-        return available;
-      });
-    }).then((upToDate) {
-      if (upToDate) return null;
-      return acquireDependencies(SolveType.GET);
-    });
-  }
-
-  /// Loads the package graph for the application and all of its transitive
-  /// dependencies.
-  ///
-  /// If [result] is passed, this loads the graph from it without re-parsing the
-  /// lockfile or any pubspecs. Otherwise, before loading, this makes sure the
-  /// lockfile and dependencies are installed and up to date.
-  Future<PackageGraph> loadPackageGraph([SolveResult result]) {
-    final completer0 = new Completer();
-    scheduleMicrotask(() {
-      try {
-        join0() {
-          new Future.value(log.progress("Loading package graph", (() {
-            final completer0 = new Completer();
-            scheduleMicrotask(() {
-              try {
-                join0() {
-                  new Future.value(ensureLockFileIsUpToDate()).then((x0) {
-                    try {
-                      x0;
-                      new Future.value(
-                          Future.wait(lockFile.packages.values.map(((id) {
-                        final completer0 = new Completer();
-                        scheduleMicrotask(() {
-                          try {
-                            var source = cache.sources[id.source];
-                            new Future.value(
-                                source.getDirectory(id)).then((x0) {
-                              try {
-                                var dir = x0;
-                                completer0.complete(
-                                    new Package.load(id.name, dir, cache.sources));
-                              } catch (e0, s0) {
-                                completer0.completeError(e0, s0);
-                              }
-                            }, onError: completer0.completeError);
-                          } catch (e, s) {
-                            completer0.completeError(e, s);
-                          }
-                        });
-                        return completer0.future;
-                      })))).then((x1) {
-                        try {
-                          var packages = x1;
-                          var packageMap =
-                              new Map.fromIterable(packages, key: ((p) {
-                            return p.name;
-                          }));
-                          packageMap[root.name] = root;
-                          completer0.complete(
-                              new PackageGraph(this, lockFile, packageMap));
-                        } catch (e0, s0) {
-                          completer0.completeError(e0, s0);
-                        }
-                      }, onError: completer0.completeError);
-                    } catch (e1, s1) {
-                      completer0.completeError(e1, s1);
-                    }
-                  }, onError: completer0.completeError);
-                }
-                if (result != null) {
-                  new Future.value(Future.wait(result.packages.map(((id) {
-                    final completer0 = new Completer();
-                    scheduleMicrotask(() {
-                      try {
-                        new Future.value(
-                            cache.sources[id.source].getDirectory(id)).then((x0) {
-                          try {
-                            var dir = x0;
-                            completer0.complete(
-                                new Package(result.pubspecs[id.name], dir));
-                          } catch (e0, s0) {
-                            completer0.completeError(e0, s0);
-                          }
-                        }, onError: completer0.completeError);
-                      } catch (e, s) {
-                        completer0.completeError(e, s);
-                      }
-                    });
-                    return completer0.future;
-                  })))).then((x2) {
-                    try {
-                      var packages = x2;
-                      completer0.complete(
-                          new PackageGraph(
-                              this,
-                              new LockFile(result.packages),
-                              new Map.fromIterable(packages, key: ((package) {
-                        return package.name;
-                      }))));
-                    } catch (e2, s2) {
-                      completer0.completeError(e2, s2);
-                    }
-                  }, onError: completer0.completeError);
-                } else {
-                  join0();
-                }
-              } catch (e, s) {
-                completer0.completeError(e, s);
-              }
-            });
-            return completer0.future;
-          }), fine: true)).then((x0) {
-            try {
-              var graph = x0;
-              _packageGraph = graph;
-              completer0.complete(graph);
-            } catch (e0, s0) {
-              completer0.completeError(e0, s0);
-            }
-          }, onError: completer0.completeError);
-        }
-        if (_packageGraph != null) {
-          completer0.complete(_packageGraph);
-        } else {
-          join0();
-        }
-      } catch (e, s) {
-        completer0.completeError(e, s);
-      }
-    });
-    return completer0.future;
-  }
-
-  /// Saves a list of concrete package versions to the `pubspec.lock` file.
-  void _saveLockFile(List<PackageId> packageIds) {
-    _lockFile = new LockFile(packageIds);
-    var lockFilePath = root.path('pubspec.lock');
-    writeTextFile(lockFilePath, _lockFile.serialize(root.dir, cache.sources));
-  }
-
-  /// Creates a self-referential symlink in the `packages` directory that allows
-  /// a package to import its own files using `package:`.
-  void _linkSelf() {
-    var linkPath = path.join(packagesDir, root.name);
-    // Create the symlink if it doesn't exist.
-    if (entryExists(linkPath)) return;
-    ensureDir(packagesDir);
-    createPackageSymlink(
-        root.name,
-        root.dir,
-        linkPath,
-        isSelfLink: true,
-        relative: true);
-  }
-
-  /// If [packageSymlinks] is true, add "packages" directories to the whitelist
-  /// of directories that may contain Dart entrypoints.
-  ///
-  /// Otherwise, delete any "packages" directories in the whitelist of
-  /// directories that may contain Dart entrypoints.
-  void _linkOrDeleteSecondaryPackageDirs() {
-    // Only the main "bin" directory gets a "packages" directory, not its
-    // subdirectories.
-    var binDir = root.path('bin');
-    if (dirExists(binDir)) _linkOrDeleteSecondaryPackageDir(binDir);
-
-    // The others get "packages" directories in subdirectories too.
-    for (var dir in ['benchmark', 'example', 'test', 'tool', 'web']) {
-      _linkOrDeleteSecondaryPackageDirsRecursively(root.path(dir));
-    }
-  }
-
-  /// If [packageSymlinks] is true, creates a symlink to the "packages"
-  /// directory in [dir] and all its subdirectories.
-  ///
-  /// Otherwise, deletes any "packages" directories in [dir] and all its
-  /// subdirectories.
-  void _linkOrDeleteSecondaryPackageDirsRecursively(String dir) {
-    if (!dirExists(dir)) return;
-    _linkOrDeleteSecondaryPackageDir(dir);
-    _listDirWithoutPackages(
-        dir).where(dirExists).forEach(_linkOrDeleteSecondaryPackageDir);
-  }
-
-  // TODO(nweiz): roll this into [listDir] in io.dart once issue 4775 is fixed.
-  /// Recursively lists the contents of [dir], excluding hidden `.DS_Store`
-  /// files and `package` files.
-  List<String> _listDirWithoutPackages(dir) {
-    return flatten(listDir(dir).map((file) {
-      if (path.basename(file) == 'packages') return [];
-      if (!dirExists(file)) return [];
-      var fileAndSubfiles = [file];
-      fileAndSubfiles.addAll(_listDirWithoutPackages(file));
-      return fileAndSubfiles;
-    }));
-  }
-
-  /// If [packageSymlinks] is true, creates a symlink to the "packages"
-  /// directory in [dir].
-  ///
-  /// Otherwise, deletes a "packages" directories in [dir] if one exists.
-  void _linkOrDeleteSecondaryPackageDir(String dir) {
-    var symlink = path.join(dir, 'packages');
-    if (entryExists(symlink)) deleteEntry(symlink);
-    if (_packageSymlinks) createSymlink(packagesDir, symlink, relative: true);
-  }
-}