Move pub into sdk/lib/_internal.

utils/pub/solver/version_solver.dart

Index: utils/pub/solver/version_solver.dart
diff --git a/utils/pub/solver/version_solver.dart b/utils/pub/solver/version_solver.dart
deleted file mode 100644
index a81626293de0e4b21137c6f2b9309c7b15acb43e..0000000000000000000000000000000000000000
--- a/utils/pub/solver/version_solver.dart
+++ /dev/null
@@ -1,308 +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 version_solver;
-
-import 'dart:async';
-import 'dart:json' as json;
-
-import '../lock_file.dart';
-import '../log.dart' as log;
-import '../package.dart';
-import '../pubspec.dart';
-import '../source.dart';
-import '../source_registry.dart';
-import '../version.dart';
-import 'backtracking_solver.dart';
-
-/// Attempts to select the best concrete versions for all of the transitive
-/// dependencies of [root] taking into account all of the [VersionConstraint]s
-/// that those dependencies place on each other and the requirements imposed by
-/// [lockFile].
-///
-/// If [useLatest] is given, then only the latest versions of the referenced
-/// packages will be used. This is for forcing an update to one or more
-/// packages.
-Future<SolveResult> resolveVersions(SourceRegistry sources, Package root,
-    {LockFile lockFile, List<String> useLatest}) {
-  log.message('Resolving dependencies...');
-
-  if (lockFile == null) lockFile = new LockFile.empty();
-  if (useLatest == null) useLatest = [];
-
-  return new BacktrackingSolver(sources, root, lockFile, useLatest).solve();
-}
-
-/// The result of a version resolution.
-class SolveResult {
-  /// Whether the solver found a complete solution or failed.
-  bool get succeeded => error == null;
-
-  /// The list of concrete package versions that were selected for each package
-  /// reachable from the root, or `null` if the solver failed.
-  final List<PackageId> packages;
-
-  /// The error that prevented the solver from finding a solution or `null` if
-  /// it was successful.
-  final SolveFailure error;
-
-  /// The number of solutions that were attempted before either finding a
-  /// successful solution or exhausting all options. In other words, one more
-  /// than the number of times it had to backtrack because it found an invalid
-  /// solution.
-  final int attemptedSolutions;
-
-  SolveResult(this.packages, this.error, this.attemptedSolutions);
-
-  String toString() {
-    if (!succeeded) {
-      return 'Failed to solve after $attemptedSolutions attempts:\n'
-             '$error';
-    }
-
-    return 'Took $attemptedSolutions tries to resolve to\n'
-           '- ${packages.join("\n- ")}';
-  }
-}
-
-/// Maintains a cache of previously-requested data: pubspecs and version lists.
-/// Used to avoid requesting the same pubspec from the server repeatedly.
-class PubspecCache {
-  final SourceRegistry _sources;
-  final _versions = new Map<PackageId, List<PackageId>>();
-  final _pubspecs = new Map<PackageId, Pubspec>();
-
-  /// The number of times a version list was requested and it wasn't cached and
-  /// had to be requested from the source.
-  int versionCacheMisses = 0;
-
-  /// The number of times a version list was requested and the cached version
-  /// was returned.
-  int versionCacheHits = 0;
-
-  /// The number of times a pubspec was requested and it wasn't cached and had
-  /// to be requested from the source.
-  int pubspecCacheMisses = 0;
-
-  /// The number of times a pubspec was requested and the cached version was
-  /// returned.
-  int pubspecCacheHits = 0;
-
-  PubspecCache(this._sources);
-
-  /// Caches [pubspec] as the [Pubspec] for the package identified by [id].
-  void cache(PackageId id, Pubspec pubspec) {
-    _pubspecs[id] = pubspec;
-  }
-
-  /// Loads the pubspec for the package identified by [id].
-  Future<Pubspec> getPubspec(PackageId id) {
-    // Complete immediately if it's already cached.
-    if (_pubspecs.containsKey(id)) {
-      pubspecCacheHits++;
-      return new Future<Pubspec>.value(_pubspecs[id]);
-    }
-
-    pubspecCacheMisses++;
-    return id.describe().then((pubspec) {
-      log.solver('requested $id pubspec');
-
-      // Cache it.
-      _pubspecs[id] = pubspec;
-      return pubspec;
-    });
-  }
-
-  /// Returns the previously cached pubspec for the package identified by [id]
-  /// or returns `null` if not in the cache.
-  Pubspec getCachedPubspec(PackageId id) => _pubspecs[id];
-
-  /// Gets the list of versions for [package] in descending order.
-  Future<List<PackageId>> getVersions(String package, Source source,
-      description) {
-    // Create a fake ID to use as a key.
-    // TODO(rnystrom): Create a separate type for (name, source, description)
-    // without a version.
-    var id = new PackageId(package, source, Version.none, description);
-
-    // See if we have it cached.
-    var versions = _versions[id];
-    if (versions != null) {
-      versionCacheHits++;
-      return new Future.value(versions);
-    }
-
-    versionCacheMisses++;
-    return source.getVersions(package, description).then((versions) {
-      var ids = versions
-          .map((version) => new PackageId(package, source, version,
-              description))
-          .toList();
-
-      // Sort by descending version so we try newer versions first.
-      ids.sort((a, b) => b.version.compareTo(a.version));
-
-      log.solver('requested $package version list');
-      _versions[id] = ids;
-      return ids;
-    });
-  }
-}
-
-/// A reference from a depending package to a package that it depends on.
-class Dependency {
-  /// The name of the package that has this dependency.
-  final String depender;
-
-  /// The referenced dependent package.
-  final PackageRef ref;
-
-  Dependency(this.depender, this.ref);
-
-  String toString() => '$depender -> $ref';
-}
-
-/// Base class for all failures that can occur while trying to resolve versions.
-class SolveFailure implements Exception {
-  /// The name of the package whose version could not be solved. Will be `null`
-  /// if the failure is not specific to one package.
-  final String package;
-
-  /// The known dependencies on [package] at the time of the failure. Will be
-  /// an empty collection if the failure is not specific to one package.
-  final Iterable<Dependency> dependencies;
-
-  SolveFailure(this.package, Iterable<Dependency> dependencies)
-      : dependencies = dependencies != null ? dependencies : <Dependency>[];
-
-  /// Writes [dependencies] to [buffer] as a bullet list. If [describe] is
-  /// passed, it will be called for each dependency and the result will be
-  /// written next to the dependency.
-  void writeDependencies(StringBuffer buffer,
-      [String describe(PackageRef ref)]) {
-    var map = {};
-    for (var dep in dependencies) {
-      map[dep.depender] = dep.ref;
-    }
-
-    var names = map.keys.toList();
-    names.sort();
-
-    for (var name in names) {
-      buffer.writeln("- '$name' ");
-      if (describe != null) {
-        buffer.writeln(describe(map[name]));
-      } else {
-        buffer.writeln("depends on version ${map[name].constraint}");
-      }
-    }
-  }
-
-  String toString() {
-    if (dependencies.isEmpty) return _message;
-
-    var buffer = new StringBuffer();
-    buffer.writeln("$_message:");
-
-    var map = {};
-    for (var dep in dependencies) {
-      map[dep.depender] = dep.ref;
-    }
-
-    var names = map.keys.toList();
-    names.sort();
-
-    for (var name in names) {
-      buffer.writeln("- '$name' ${_describeDependency(map[name])}");
-    }
-
-    return buffer.toString();
-  }
-
-  /// A message describing the specific kind of solve failure.
-  String get _message;
-
-  /// Describes a dependencie's reference in the output message. Override this
-  /// to highlight which aspect of [ref] led to the failure.
-  String _describeDependency(PackageRef ref) =>
-      "depends on version ${ref.constraint}";
-}
-
-/// Exception thrown when the [VersionSolver] fails to find a solution after a
-/// certain number of iterations.
-class CouldNotSolveException extends SolveFailure {
-  CouldNotSolveException([String message])
-      : super(null, null),
-        _message = (message != null) ? message :
-            "Could not find a solution that met all constraints.";
-
-  /// A message describing the specific kind of solve failure.
-  final String _message;
-}
-
-/// Exception thrown when the [VersionConstraint] used to match a package is
-/// valid (i.e. non-empty), but there are no available versions of the package
-/// that fit that constraint.
-class NoVersionException extends SolveFailure {
-  final VersionConstraint constraint;
-
-  NoVersionException(String package, this.constraint,
-      Iterable<Dependency> dependencies)
-      : super(package, dependencies);
-
-  String get _message => "Package '$package' has no versions that match "
-      "$constraint derived from";
-}
-
-// TODO(rnystrom): Report the list of depending packages and their constraints.
-/// Exception thrown when the most recent version of [package] must be selected,
-/// but doesn't match the [VersionConstraint] imposed on the package.
-class CouldNotUpdateException extends SolveFailure {
-  final VersionConstraint constraint;
-  final Version best;
-
-  CouldNotUpdateException(String package, this.constraint, this.best)
-      : super(package, null);
-
-  String get _message =>
-      "The latest version of '$package', $best, does not match $constraint.";
-}
-
-/// Exception thrown when the [VersionConstraint] used to match a package is
-/// the empty set: in other words, multiple packages depend on it and have
-/// conflicting constraints that have no overlap.
-class DisjointConstraintException extends SolveFailure {
-  DisjointConstraintException(String package, Iterable<Dependency> dependencies)
-      : super(package, dependencies);
-
-  String get _message => "Incompatible version constraints on '$package'";
-}
-
-/// Exception thrown when two packages with the same name but different sources
-/// are depended upon.
-class SourceMismatchException extends SolveFailure {
-
-  SourceMismatchException(String package, Iterable<Dependency> dependencies)
-      : super(package, dependencies);
-
-  String get _message => "Incompatible dependencies on '$package'";
-
-  String _describeDependency(PackageRef ref) =>
-      "depends on it from source ${ref.source}";
-}
-
-/// Exception thrown when two packages with the same name and source but
-/// different descriptions are depended upon.
-class DescriptionMismatchException extends SolveFailure {
-  DescriptionMismatchException(String package,
-      Iterable<Dependency> dependencies)
-      : super(package, dependencies);
-
-  String get _message => "Incompatible dependencies on '$package'";
-
-  String _describeDependency(PackageRef ref) {
-    // TODO(nweiz): Dump descriptions to YAML when that's supported.
-    return "depends on it with description ${json.stringify(ref.description)}";
-  }
-}