Files
sdk/utils/pub/system_cache.dart
T
2012-05-24 23:29:18 +00:00

92 lines
2.8 KiB
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('package.dart');
#import('source_registry.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. from the SDK) don't use this cache.
*/
class SystemCache {
/**
* The root directory where this package cache is located.
*/
final String rootDir;
/**
* 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();
/**
* Loads all of the package ids in the cache and returns them.
*/
Future<List<PackageId>> listAll() {
return listDir(rootDir).chain((paths) {
final sources = paths.map((path) {
final source = sources[basename(path)];
return listDir(path).transform((subpaths) {
// TODO(rnystrom): Once there are cached packages and this path is
// being used, figure out how version numbers should be acquired.
return subpaths.map((subpath) =>
new PackageId(basename(subpath), source, Version.none));
});
});
return Futures.wait(sources).transform(flatten);
});
}
/**
* 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 IllegalArgumentException("Package $id is not cacheable.");
}
var pending = _pendingInstalls[id];
if (pending != null) return pending;
var path = join(rootDir, id.source.name, id.source.packageName(id));
var future = exists(path).chain((exists) {
// TODO(nweiz): better error handling
if (exists) throw 'Package $id is already installed.';
return ensureDir(dirname(path));
}).chain((_) {
return id.source.install(id, path);
}).chain((found) {
if (!found) {
throw 'Package ${id.fullName} not found in source "${id.source.name}".';
}
return Package.load(path, sources);
});
always(future, () => _pendingInstalls.remove(id));
_pendingInstalls[id] = future;
return future;
}
}