nweiz@google.com
5a6998d14e
This fixes a race condition in commit 9094. Review URL: https://chromiumcodereview.appspot.com//10636045 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@9132 260f80e4-7a28-3924-810f-c04153c831b5
93 lines
2.8 KiB
Dart
93 lines
2.8 KiB
Dart
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#library('system_cache');
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#import('io.dart');
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#import('package.dart');
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#import('source_registry.dart');
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#import('utils.dart');
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/**
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* The system-wide cache of installed packages.
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*
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* This cache contains all packages that are downloaded from the internet.
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* Packages that are available locally (e.g. from the SDK) don't use this cache.
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*/
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class SystemCache {
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/**
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* The root directory where this package cache is located.
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*/
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final String rootDir;
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/**
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* Packages which are currently being asynchronously installed to the cache.
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*/
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final Map<PackageId, Future<Package>> _pendingInstalls;
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/**
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* The sources from which to install packages.
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*/
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final SourceRegistry sources;
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/**
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* Creates a new package cache which is backed by the given directory on the
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* user's file system.
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*/
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SystemCache(this.rootDir)
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: _pendingInstalls = new Map<PackageId, Future<Package>>(),
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sources = new SourceRegistry();
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/**
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* Loads all of the package ids in the cache and returns them.
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*/
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Future<List<PackageId>> listAll() {
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return listDir(rootDir).chain((paths) {
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final sources = paths.map((path) {
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final source = sources[basename(path)];
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return listDir(path).transform((subpaths) {
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// TODO(rnystrom): Once there are cached packages and this path is
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// being used, figure out how version numbers should be acquired.
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return subpaths.map((subpath) =>
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new PackageId(basename(subpath), source, Version.none));
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});
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});
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return Futures.wait(sources).transform(flatten);
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});
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}
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/**
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* Ensures that the package identified by [id] is installed to the cache,
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* loads it, and returns it.
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*
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* It is an error to try installing a package from a source with `shouldCache
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* == false` to the system cache.
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*/
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Future<Package> install(PackageId id) {
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if (!id.source.shouldCache) {
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throw new IllegalArgumentException("Package $id is not cacheable.");
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}
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var pending = _pendingInstalls[id];
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if (pending != null) return pending;
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var sourceDir = join(rootDir, id.source.name);
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var path = id.source.systemCacheDirectory(id, sourceDir);
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var future = exists(path).chain((exists) {
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// TODO(nweiz): better error handling
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if (exists) throw 'Package $id is already installed.';
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return ensureDir(dirname(path));
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}).chain((_) {
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return id.source.install(id, path);
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}).chain((found) {
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if (!found) throw 'Package $id not found.';
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return Package.load(path, sources);
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});
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always(future, () => _pendingInstalls.remove(id));
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_pendingInstalls[id] = future;
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return future;
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}
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}
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