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// Copyright (c) 2016, 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.
import 'package:http/http.dart' as http;
import 'no_package_resolver.dart';
import 'package_config_resolver.dart';
import 'package_resolver.dart';
import 'package_root_resolver.dart';
import 'utils.dart';
/// A class that defines how to resolve `package:` URIs.
/// This includes the information necessary to resolve `package:` URIs using
/// either a package config or a package root. It can be used both as a standard
/// cross-package representation of the user's configuration, and as a means of
/// concretely locating packages and the assets they contain.
/// Unlike [PackageResolver], all members on this are synchronous, which may
/// require that more data be loaded up front. This is useful when primarily
/// dealing with user-created package resolution strategies, whereas
/// [PackageInfo] is usually preferable when the current Isolate's package
/// resolution logic may be used.
/// This class should not be implemented by user code.
abstract class SyncPackageResolver {
/// The map contained in the parsed package config.
/// This maps package names to the base URIs for those packages. These are
/// already resolved relative to [packageConfigUri], so if they're relative
/// they should be considered relative to [Uri.base]. They're normalized to
/// ensure that all URLs end with a trailing slash.
/// [urlFor] should generally be used rather than looking up package URLs in
/// this map, to ensure that code works with a package root as well as a
/// package config.
/// Returns `null` when using a [packageRoot] for resolution, or when no
/// package resolution is being used.
Map<String, Uri> get packageConfigMap;
/// The URI for the package config.
/// This is the URI from which [packageConfigMap] was parsed, if that's
/// available. Otherwise, it's a `data:` URI containing a serialized
/// representation of [packageConfigMap]. This `data:` URI should be accepted
/// by all Dart tools.
/// Note that if this is a `data:` URI, it's likely not safe to pass as a
/// parameter to a Dart process due to length limits.
/// Returns `null` when using a [packageRoot] for resolution, or when no
/// package resolution is being used.
Uri get packageConfigUri;
/// The base URL for resolving `package:` URLs.
/// This is normalized so that it always ends with a trailing slash.
/// Returns `null` when using a [packageConfigMap] for resolution, or when no
/// package resolution is being used.
Uri get packageRoot;
/// Returns a wrapper for [this] that implements [PackageResolver].
PackageResolver get asAsync;
/// Returns the argument to pass to a subprocess to get it to use this package
/// resolution strategy when resolving `package:` URIs.
/// This uses the `--package-root` or `--package` flags, which are the
/// convention supported by the Dart VM and dart2js.
/// Note that if [packageConfigUri] is a `data:` URI, it may be too large to
/// pass on the command line.
/// Returns `null` if no package resolution is in use.
String get processArgument;
/// Returns a package resolution strategy describing how the current isolate
/// resolves `package:` URIs.
/// This may throw exceptions if loading or parsing the isolate's package map
/// fails.
static final Future<SyncPackageResolver> current =
/// Returns a package resolution strategy that is unable to resolve any
/// `package:` URIs.
static final SyncPackageResolver none = NoPackageResolver();
/// Loads a package config file from [uri] and returns its package resolution
/// strategy.
/// This supports `file:`, `http:`, `data:` and `package:` URIs. It throws an
/// [UnsupportedError] for any other schemes. If [client] is passed and an
/// HTTP request is needed, it's used to make that request; otherwise, a
/// default client is used.
/// [uri] may be a [String] or a [Uri].
static Future<SyncPackageResolver> loadConfig(uri,
{http.Client client}) async {
uri = asUri(uri, "uri");
return SyncPackageResolver.config(await loadConfigMap(uri, client: client),
uri: uri);
/// Returns the package resolution strategy for the given [packageConfigMap].
/// If passed, [uri] specifies the URI from which [packageConfigMap] was
/// loaded. It may be a [String] or a [Uri].
/// Whether or not [uri] is passed, [packageConfigMap] is expected to be
/// fully-resolved. That is, any relative URIs in the original package config
/// source should be resolved relative to its location.
factory SyncPackageResolver.config(Map<String, Uri> packageConfigMap, {uri}) =
/// Returns the package resolution strategy for the given [packageRoot], which
/// may be a [String] or a [Uri].
factory SyncPackageResolver.root(packageRoot) = PackageRootResolver;
/// Resolves [packageUri] according to this package resolution strategy.
/// [packageUri] may be a [String] or a [Uri]. This throws a [FormatException]
/// if [packageUri] isn't a `package:` URI or doesn't have at least one path
/// segment.
/// If [packageUri] refers to a package that's not in the package spec, this
/// returns `null`.
Uri resolveUri(packageUri);
/// Returns the resolved URL for [package] and [path].
/// This is equivalent to `resolveUri("package:$package/")` or
/// `resolveUri("package:$package/$path")`, depending on whether [path] was
/// passed.
/// If [package] refers to a package that's not in the package spec, this
/// returns `null`.
Uri urlFor(String package, [String path]);
/// Returns the `package:` URI for [url].
/// If [url] can't be referred to using a `package:` URI, returns `null`.
/// [url] may be a [String] or a [Uri].
Uri packageUriFor(url);
/// Returns the path on the local filesystem to the root of [package], or
/// `null` if the root cannot be found.
/// **Note**: this assumes a pub-style package layout. In particular:
/// * If a package root is being used, this assumes that it contains symlinks
/// to packages' lib/ directories.
/// * If a package config is being used, this assumes that each entry points
/// to a package's lib/ directory.
/// If these assumptions are broken, this may return `null` or it may return
/// an invalid result.
/// Returns `null` if the package root is not a `file:` URI, or if the package
/// config entry for [package] is not a `file:` URI.
String packagePath(String package);