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

sdk/lib/_internal/pub_generated/lib/src/barback/load_all_transformers.dart

Index: sdk/lib/_internal/pub_generated/lib/src/barback/load_all_transformers.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/barback/load_all_transformers.dart b/sdk/lib/_internal/pub_generated/lib/src/barback/load_all_transformers.dart
deleted file mode 100644
index fc593774d8635b559f8f0b0b55a8b897f65967e5..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/lib/src/barback/load_all_transformers.dart
+++ /dev/null
@@ -1,276 +0,0 @@
-// Copyright (c) 2013, 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.load_all_transformers;
-
-import 'dart:async';
-
-import 'package:barback/barback.dart';
-
-import '../log.dart' as log;
-import '../package_graph.dart';
-import '../utils.dart';
-import 'asset_environment.dart';
-import 'barback_server.dart';
-import 'dependency_computer.dart';
-import 'transformer_id.dart';
-import 'transformer_loader.dart';
-
-/// Loads all transformers depended on by packages in [environment].
-///
-/// This uses [environment]'s primary server to serve the Dart files from which
-/// transformers are loaded, then adds the transformers to
-/// `environment.barback`.
-///
-/// Any built-in transformers that are provided by the environment will
-/// automatically be added to the end of the root package's cascade.
-///
-/// If [entrypoints] is passed, only transformers necessary to run those
-/// entrypoints will be loaded.
-Future loadAllTransformers(AssetEnvironment environment,
-    BarbackServer transformerServer, {Iterable<AssetId> entrypoints}) {
-  final completer0 = new Completer();
-  scheduleMicrotask(() {
-    try {
-      var dependencyComputer = new DependencyComputer(environment.graph);
-      var necessaryTransformers;
-      join0() {
-        var transformersNeededByTransformers =
-            dependencyComputer.transformersNeededByTransformers(necessaryTransformers);
-        var buffer = new StringBuffer();
-        buffer.writeln("Transformer dependencies:");
-        transformersNeededByTransformers.forEach(((id, dependencies) {
-          if (dependencies.isEmpty) {
-            buffer.writeln("$id: -");
-          } else {
-            buffer.writeln("$id: ${toSentence(dependencies)}");
-          }
-        }));
-        log.fine(buffer);
-        var stagedTransformers =
-            _stageTransformers(transformersNeededByTransformers);
-        var packagesThatUseTransformers =
-            _packagesThatUseTransformers(environment.graph);
-        var loader = new TransformerLoader(environment, transformerServer);
-        join1(x0) {
-          var cache = x0;
-          var first = true;
-          var it0 = stagedTransformers.iterator;
-          break0() {
-            join2() {
-              new Future.value(
-                  Future.wait(environment.graph.packages.values.map(((package) {
-                final completer0 = new Completer();
-                scheduleMicrotask(() {
-                  try {
-                    new Future.value(
-                        loader.transformersForPhases(package.pubspec.transformers)).then((x0) {
-                      try {
-                        var phases = x0;
-                        var transformers =
-                            environment.getBuiltInTransformers(package);
-                        join0() {
-                          join1() {
-                            newFuture((() {
-                              return environment.barback.updateTransformers(
-                                  package.name,
-                                  phases);
-                            }));
-                            completer0.complete();
-                          }
-                          if (phases.isEmpty) {
-                            completer0.complete(null);
-                          } else {
-                            join1();
-                          }
-                        }
-                        if (transformers != null) {
-                          phases.add(transformers);
-                          join0();
-                        } else {
-                          join0();
-                        }
-                      } 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);
-            }
-            if (cache != null) {
-              cache.save();
-              join2();
-            } else {
-              join2();
-            }
-          }
-          var trampoline0;
-          continue0() {
-            trampoline0 = null;
-            if (it0.moveNext()) {
-              var stage = it0.current;
-              join3(x2) {
-                var snapshotPath = x2;
-                first = false;
-                new Future.value(
-                    loader.load(stage, snapshot: snapshotPath)).then((x3) {
-                  trampoline0 = () {
-                    trampoline0 = null;
-                    try {
-                      x3;
-                      var packagesToUpdate = unionAll(stage.map(((id) {
-                        return packagesThatUseTransformers[id];
-                      })));
-                      new Future.value(
-                          Future.wait(packagesToUpdate.map(((packageName) {
-                        final completer0 = new Completer();
-                        scheduleMicrotask(() {
-                          try {
-                            var package =
-                                environment.graph.packages[packageName];
-                            new Future.value(
-                                loader.transformersForPhases(package.pubspec.transformers)).then((x0) {
-                              try {
-                                var phases = x0;
-                                environment.barback.updateTransformers(
-                                    packageName,
-                                    phases);
-                                completer0.complete();
-                              } catch (e0, s0) {
-                                completer0.completeError(e0, s0);
-                              }
-                            }, onError: completer0.completeError);
-                          } catch (e, s) {
-                            completer0.completeError(e, s);
-                          }
-                        });
-                        return completer0.future;
-                      })))).then((x4) {
-                        trampoline0 = () {
-                          trampoline0 = null;
-                          try {
-                            x4;
-                            trampoline0 = continue0;
-                            do trampoline0(); while (trampoline0 != null);
-                          } catch (e1, s1) {
-                            completer0.completeError(e1, s1);
-                          }
-                        };
-                        do trampoline0(); while (trampoline0 != null);
-                      }, onError: completer0.completeError);
-                    } catch (e2, s2) {
-                      completer0.completeError(e2, s2);
-                    }
-                  };
-                  do trampoline0(); while (trampoline0 != null);
-                }, onError: completer0.completeError);
-              }
-              if (cache == null || !first) {
-                join3(null);
-              } else {
-                join3(cache.snapshotPath(stage));
-              }
-            } else {
-              break0();
-            }
-          }
-          trampoline0 = continue0;
-          do trampoline0(); while (trampoline0 != null);
-        }
-        if (environment.rootPackage.dir == null) {
-          join1(null);
-        } else {
-          join1(environment.graph.loadTransformerCache());
-        }
-      }
-      if (entrypoints != null) {
-        join4() {
-          necessaryTransformers =
-              unionAll(entrypoints.map(dependencyComputer.transformersNeededByLibrary));
-          join5() {
-            join0();
-          }
-          if (necessaryTransformers.isEmpty) {
-            log.fine(
-                "No transformers are needed for ${toSentence(entrypoints)}.");
-            completer0.complete(null);
-          } else {
-            join5();
-          }
-        }
-        if (entrypoints.isEmpty) {
-          completer0.complete(null);
-        } else {
-          join4();
-        }
-      } else {
-        join0();
-      }
-    } catch (e, s) {
-      completer0.completeError(e, s);
-    }
-  });
-  return completer0.future;
-}
-
-/// Given [transformerDependencies], a directed acyclic graph, returns a list of
-/// "stages" (sets of transformers).
-///
-/// Each stage must be fully loaded and passed to barback before the next stage
-/// can be safely loaded. However, transformers within a stage can be safely
-/// loaded in parallel.
-List<Set<TransformerId>> _stageTransformers(Map<TransformerId,
-    Set<TransformerId>> transformerDependencies) {
-  // A map from transformer ids to the indices of the stages that those
-  // transformer ids should end up in. Populated by [stageNumberFor].
-  var stageNumbers = {};
-  var stages = [];
-
-  stageNumberFor(id) {
-    // Built-in transformers don't have to be loaded in stages, since they're
-    // run from pub's source. Return -1 so that the "next stage" is 0.
-    if (id.isBuiltInTransformer) return -1;
-
-    if (stageNumbers.containsKey(id)) return stageNumbers[id];
-    var dependencies = transformerDependencies[id];
-    stageNumbers[id] =
-        dependencies.isEmpty ? 0 : maxAll(dependencies.map(stageNumberFor)) + 1;
-    return stageNumbers[id];
-  }
-
-  for (var id in transformerDependencies.keys) {
-    var stageNumber = stageNumberFor(id);
-    if (stages.length <= stageNumber) stages.length = stageNumber + 1;
-    if (stages[stageNumber] == null) stages[stageNumber] = new Set();
-    stages[stageNumber].add(id);
-  }
-
-  return stages;
-}
-
-/// Returns a map from transformer ids to all packages in [graph] that use each
-/// transformer.
-Map<TransformerId, Set<String>> _packagesThatUseTransformers(PackageGraph graph)
-    {
-  var results = {};
-  for (var package in graph.packages.values) {
-    for (var phase in package.pubspec.transformers) {
-      for (var config in phase) {
-        results.putIfAbsent(config.id, () => new Set()).add(package.name);
-      }
-    }
-  }
-  return results;
-}