SourceFactory interface extraction.

pkg/analyzer/lib/src/context/source.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file

[Brian Wilkerson, 2016/01/28 18:55:41]

I've been preserving the copyright from the original file when extracting code
to a new file. Not sure it's important.

[pquitslund, 2016/01/28 18:58:20]

Done.

+// 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 analyzer.src.context.source;
+
+import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/file_system/physical_file_system.dart';
+import 'package:analyzer/source/package_map_resolver.dart';
+import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/java_core.dart';
+import 'package:analyzer/src/generated/java_engine.dart';
+import 'package:analyzer/src/generated/sdk.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/generated/utilities_dart.dart' as utils;
+import 'package:package_config/packages.dart';
+
+/**
+ * Instances of the class `SourceFactory` resolve possibly relative URI's
+ * against an existing [Source].
+ */
+class SourceFactoryImpl implements SourceFactory {

[Brian Wilkerson, 2016/01/28 18:55:41]

I'm assuming this was just copied and renamed from the old version of
SourceFactory. If there are changes I should look at, let me know.

[pquitslund, 2016/01/28 18:58:20]

Nope.  _resolvers => resolvers is all.

+  /**
+   * The analysis context that this source factory is associated with.
+   */
+  AnalysisContext context;
+
+  /**
+   * URI processor used to find mappings for `package:` URIs found in a
+   * `.packages` config file.
+   */
+  final Packages _packages;
+
+  /**
+   * Resource provider used in working with package maps.
+   */
+  final ResourceProvider _resourceProvider;
+
+  /**
+   * The resolvers used to resolve absolute URI's.
+   */
+  final List<UriResolver> resolvers;
+
+  /**
+   * The predicate to determine is [Source] is local.
+   */
+  LocalSourcePredicate _localSourcePredicate = LocalSourcePredicate.NOT_SDK;
+
+  /**
+   * Initialize a newly created source factory with the given absolute URI
+   * [resolvers] and optional [packages] resolution helper.
+   */
+  SourceFactoryImpl(this.resolvers,
+      [this._packages, ResourceProvider resourceProvider])
+      : _resourceProvider = resourceProvider != null
+            ? resourceProvider
+            : PhysicalResourceProvider.INSTANCE;
+
+  /**
+   * Return the [DartSdk] associated with this [SourceFactory], or `null` if
+   * there is no such SDK.
+   *
+   * @return the [DartSdk] associated with this [SourceFactory], or `null` if
+   *         there is no such SDK
+   */
+  DartSdk get dartSdk {
+    for (UriResolver resolver in resolvers) {
+      if (resolver is DartUriResolver) {
+        DartUriResolver dartUriResolver = resolver;
+        return dartUriResolver.dartSdk;
+      }
+    }
+    return null;
+  }
+
+  /**
+   * Sets the [LocalSourcePredicate].
+   *
+   * @param localSourcePredicate the predicate to determine is [Source] is local
+   */
+  void set localSourcePredicate(LocalSourcePredicate localSourcePredicate) {
+    this._localSourcePredicate = localSourcePredicate;
+  }
+
+  /// A table mapping package names to paths of directories containing
+  /// the package (or [null] if there is no registered package URI resolver).
+  Map<String, List<Folder>> get packageMap {
+    // Start by looking in .packages.
+    if (_packages != null) {
+      Map<String, List<Folder>> packageMap = <String, List<Folder>>{};
+      _packages.asMap().forEach((String name, Uri uri) {
+        if (uri.scheme == 'file' || uri.scheme == '' /* unspecified */) {
+          packageMap[name] = <Folder>[
+            _resourceProvider.getFolder(uri.toFilePath())
+          ];
+        }
+      });
+      return packageMap;
+    }
+
+    // Default to the PackageMapUriResolver.
+    PackageMapUriResolver resolver = resolvers
+        .firstWhere((r) => r is PackageMapUriResolver, orElse: () => null);
+    return resolver != null ? resolver.packageMap : null;
+  }
+
+  /**
+   * Return a source factory that will resolve URI's in the same way that this
+   * source factory does.
+   */
+  SourceFactory clone() {
+    SourceFactory factory =
+        new SourceFactory(resolvers, _packages, _resourceProvider);
+    factory.localSourcePredicate = _localSourcePredicate;
+    return factory;
+  }
+
+  /**
+   * Return a source object representing the given absolute URI, or `null` if
+   * the URI is not a valid URI or if it is not an absolute URI.
+   *
+   * @param absoluteUri the absolute URI to be resolved
+   * @return a source object representing the absolute URI
+   */
+  Source forUri(String absoluteUri) {
+    try {
+      Uri uri = parseUriWithException(absoluteUri);
+      if (uri.isAbsolute) {
+        return _internalResolveUri(null, uri);
+      }
+    } catch (exception, stackTrace) {
+      AnalysisEngine.instance.logger.logError(
+          "Could not resolve URI: $absoluteUri",
+          new CaughtException(exception, stackTrace));
+    }
+    return null;
+  }
+
+  /**
+   * Return a source object representing the given absolute URI, or `null` if
+   * the URI is not an absolute URI.
+   *
+   * @param absoluteUri the absolute URI to be resolved
+   * @return a source object representing the absolute URI
+   */
+  Source forUri2(Uri absoluteUri) {
+    if (absoluteUri.isAbsolute) {
+      try {
+        return _internalResolveUri(null, absoluteUri);
+      } on AnalysisException catch (exception, stackTrace) {
+        AnalysisEngine.instance.logger.logError(
+            "Could not resolve URI: $absoluteUri",
+            new CaughtException(exception, stackTrace));
+      }
+    }
+    return null;
+  }
+
+  /**
+   * Return a source object that is equal to the source object used to obtain
+   * the given encoding.
+   *
+   * @param encoding the encoding of a source object
+   * @return a source object that is described by the given encoding
+   * @throws IllegalArgumentException if the argument is not a valid encoding
+   * See [Source.encoding].
+   */
+  Source fromEncoding(String encoding) {
+    Source source = forUri(encoding);
+    if (source == null) {
+      throw new IllegalArgumentException(
+          "Invalid source encoding: '$encoding'");
+    }
+    return source;
+  }
+
+  /**
+   * Determines if the given [Source] is local.
+   *
+   * @param source the [Source] to analyze
+   * @return `true` if the given [Source] is local
+   */
+  bool isLocalSource(Source source) => _localSourcePredicate.isLocal(source);
+
+  /**
+   * Return a source representing the URI that results from resolving the given
+   * (possibly relative) [containedUri] against the URI associated with the
+   * [containingSource], whether or not the resulting source exists, or `null`
+   * if either the [containedUri] is invalid or if it cannot be resolved against
+   * the [containingSource]'s URI.
+   */
+  Source resolveUri(Source containingSource, String containedUri) {
+    if (containedUri == null || containedUri.isEmpty) {
+      return null;
+    }
+    try {
+      // Force the creation of an escaped URI to deal with spaces, etc.
+      return _internalResolveUri(
+          containingSource, parseUriWithException(containedUri));
+    } on URISyntaxException {
+      return null;
+    } catch (exception, stackTrace) {
+      String containingFullName =
+          containingSource != null ? containingSource.fullName : '<null>';
+      AnalysisEngine.instance.logger.logInformation(
+          "Could not resolve URI ($containedUri) "
+          "relative to source ($containingFullName)",
+          new CaughtException(exception, stackTrace));
+      return null;
+    }
+  }
+
+  /**
+   * Return an absolute URI that represents the given source, or `null` if a
+   * valid URI cannot be computed.
+   *
+   * @param source the source to get URI for
+   * @return the absolute URI representing the given source
+   */
+  Uri restoreUri(Source source) {
+    // First see if a resolver can restore the URI.
+    for (UriResolver resolver in resolvers) {
+      Uri uri = resolver.restoreAbsolute(source);
+      if (uri != null) {
+        // Now see if there's a package mapping.
+        Uri packageMappedUri = _getPackageMapping(uri);
+        if (packageMappedUri != null) {
+          return packageMappedUri;
+        }
+        // Fall back to the resolver's computed URI.
+        return uri;
+      }
+    }
+
+    return null;
+  }
+
+  Uri _getPackageMapping(Uri sourceUri) {
+    if (_packages == null) {
+      return null;
+    }
+    if (sourceUri.scheme != 'file') {
+      //TODO(pquitslund): verify this works for non-file URIs.
+      return null;
+    }
+
+    Uri packageUri;
+    _packages.asMap().forEach((String name, Uri uri) {
+      if (packageUri == null) {
+        if (utils.startsWith(sourceUri, uri)) {
+          packageUri = Uri.parse(
+              'package:$name/${sourceUri.path.substring(uri.path.length)}');
+        }
+      }
+    });
+    return packageUri;
+  }
+
+  /**
+   * Return a source object representing the URI that results from resolving
+   * the given (possibly relative) contained URI against the URI associated
+   * with an existing source object, or `null` if the URI could not be resolved.
+   *
+   * @param containingSource the source containing the given URI
+   * @param containedUri the (possibly relative) URI to be resolved against the
+   *        containing source
+   * @return the source representing the contained URI
+   * @throws AnalysisException if either the contained URI is invalid or if it
+   *         cannot be resolved against the source object's URI
+   */
+  Source _internalResolveUri(Source containingSource, Uri containedUri) {
+    if (!containedUri.isAbsolute) {
+      if (containingSource == null) {
+        throw new AnalysisException(
+            "Cannot resolve a relative URI without a containing source: "
+            "$containedUri");
+      }
+      containedUri = containingSource.resolveRelativeUri(containedUri);
+    }
+
+    Uri actualUri = containedUri;
+
+    // Check .packages and update target and actual URIs as appropriate.
+    if (_packages != null && containedUri.scheme == 'package') {
+      Uri packageUri = null;
+      try {
+        packageUri =
+            _packages.resolve(containedUri, notFound: (Uri packageUri) => null);
+      } on ArgumentError {
+        // Fall through to try resolvers.
+      }
+
+      if (packageUri != null) {
+        // Ensure scheme is set.
+        if (packageUri.scheme == '') {
+          packageUri = packageUri.replace(scheme: 'file');
+        }
+        containedUri = packageUri;
+      }
+    }
+
+    for (UriResolver resolver in resolvers) {
+      Source result = resolver.resolveAbsolute(containedUri, actualUri);
+      if (result != null) {
+        return result;
+      }
+    }
+
+    return null;
+  }
+}