Optimize more megamorphic dispatch sites

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

 // Copyright (c) 2015, 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 analyzer.src.context.source;
 
 import 'dart:collection';
 
 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:analyzer/src/util/fast_uri.dart';
 import 'package:package_config/packages.dart';
 
 /**
  * Instances of the class `SourceFactory` resolve possibly relative URI's
  * against an existing [Source].
  */
 class SourceFactoryImpl implements SourceFactory {
-  /**
-   * The analysis context that this source factory is associated with.
-   */
   @override
   AnalysisContext context;
 
   /**
    * URI processor used to find mappings for `package:` URIs found in a
    * `.packages` config file.
    */
   final Packages _packages;
 
   /**
@@ skipping 19 matching lines @@
 
   /**
    * 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 ?? 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
-   */
   @override
   DartSdk get dartSdk {
-    for (UriResolver resolver in resolvers) {
+    List<UriResolver> resolvers = this.resolvers;
+    int length = resolvers.length;
+    for (int i = 0; i < length; i++) {
+      UriResolver resolver = resolvers[i];
       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
-   */
   @override
   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).
   @override
   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?.packageMap;
   }
 
-  /**
-   * Return a source factory that will resolve URI's in the same way that this
-   * source factory does.
-   */
   @override
   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
-   */
   @override
   Source forUri(String absoluteUri) {
     try {
       Uri uri = FastUri.parse(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
-   */
   @override
   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].
-   */
   @override
   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
-   */
   @override
   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.
-   */
   @override
   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, FastUri.parse(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
-   */
   @override
   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;
@@ skipping 75 matching lines @@
       for (UriResolver resolver in resolvers) {
         Source result = resolver.resolveAbsolute(containedUri, actualUri);
         if (result != null) {
           return result;
         }
       }
       return null;
     });
   }
 }