Move pub into sdk/lib/_internal.

utils/pub/system_cache.dart

-// 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 system_cache;
-
-import 'dart:io';
-import 'dart:async';
-
-import 'package:pathos/path.dart' as path;
-
-import 'git_source.dart';
-import 'hosted_source.dart';
-import 'io.dart';
-import 'io.dart' as io show createTempDir;
-import 'log.dart' as log;
-import 'package.dart';
-import 'path_source.dart';
-import 'pubspec.dart';
-import 'source.dart';
-import 'source_registry.dart';
-import 'utils.dart';
-import 'version.dart';
-
-/// The system-wide cache of installed packages.
-///
-/// This cache contains all packages that are downloaded from the internet.
-/// Packages that are available locally (e.g. path dependencies) don't use this
-/// cache.
-class SystemCache {
-  /// The root directory where this package cache is located.
-  final String rootDir;
-
-  String get tempDir => path.join(rootDir, '_temp');
-
-  /// Packages which are currently being asynchronously installed to the cache.
-  final Map<PackageId, Future<Package>> _pendingInstalls;
-
-  /// The sources from which to install packages.
-  final SourceRegistry sources;
-
-  /// Creates a new package cache which is backed by the given directory on the
-  /// user's file system.
-  SystemCache(this.rootDir)
-  : _pendingInstalls = new Map<PackageId, Future<Package>>(),
-    sources = new SourceRegistry();
-
-  /// Creates a system cache and registers the standard set of sources.
-  factory SystemCache.withSources(String rootDir) {
-    var cache = new SystemCache(rootDir);
-    cache.register(new GitSource());
-    cache.register(new HostedSource());
-    cache.register(new PathSource());
-    cache.sources.setDefault('hosted');
-    return cache;
-  }
-
-  /// Registers a new source. This source must not have the same name as a
-  /// source that's already been registered.
-  void register(Source source) {
-    source.bind(this);
-    sources.register(source);
-  }
-
-  /// Gets the package identified by [id]. If the package is already cached,
-  /// reads it from the cache. Otherwise, requests it from the source.
-  Future<Pubspec> describe(PackageId id) {
-    if (id.isRoot) throw new ArgumentError("Cannot describe the root package.");
-
-    // Try to get it from the system cache first.
-    if (id.source.shouldCache) {
-      return id.systemCacheDirectory.then((packageDir) {
-        if (!fileExists(path.join(packageDir, "pubspec.yaml"))) {
-          return id.source.describe(id);
-        }
-
-        return new Pubspec.load(id.name, packageDir, sources);
-      });
-    }
-
-    // Not cached, so get it from the source.
-    return id.source.describe(id);
-  }
-
-  /// Ensures that the package identified by [id] is installed to the cache,
-  /// loads it, and returns it.
-  ///
-  /// It is an error to try installing a package from a source with `shouldCache
-  /// == false` to the system cache.
-  Future<Package> install(PackageId id) {
-    if (!id.source.shouldCache) {
-      throw new ArgumentError("Package $id is not cacheable.");
-    }
-
-    var pending = _pendingInstalls[id];
-    if (pending != null) return pending;
-
-    var future = id.source.installToSystemCache(id)
-        .whenComplete(() { _pendingInstalls.remove(id); });
-    _pendingInstalls[id] = future;
-    return future;
-  }
-
-  /// Create a new temporary directory within the system cache. The system
-  /// cache maintains its own temporary directory that it uses to stage
-  /// packages into while installing. It uses this instead of the OS's system
-  /// temp directory to ensure that it's on the same volume as the pub system
-  /// cache so that it can move the directory from it.
-  String createTempDir() {
-    var temp = ensureDir(tempDir);
-    return io.createTempDir(path.join(temp, 'dir'));
-  }
-
-  /// Deletes the system cache's internal temp directory.
-  void deleteTempDir() {
-    log.fine('Clean up system cache temp directory $tempDir.');
-    if (dirExists(tempDir)) deleteEntry(tempDir);
-  }
-}