Stop running pub get at gclient sync time and fix build bugs

mojo/public/dart/third_party/analyzer/lib/src/generated/source.dart

+// Copyright (c) 2014, 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 engine.source;
+
+import 'dart:collection';
+import "dart:math" as math;
+
+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/utilities_dart.dart' as utils;
+import 'package:analyzer/task/model.dart';
+import 'package:package_config/packages.dart';
+import 'package:path/path.dart' as pathos;
+
+import 'engine.dart';
+import 'java_core.dart';
+import 'java_engine.dart';
+import 'java_io.dart' show JavaFile;
+import 'sdk.dart' show DartSdk;
+import 'source_io.dart' show FileBasedSource;
+
+/**
+ * A function that is used to visit [ContentCache] entries.
+ */
+typedef void ContentCacheVisitor(String fullPath, int stamp, String contents);
+
+/**
+ * A cache used to override the default content of a [Source].
+ */
+class ContentCache {
+  /**
+   * A table mapping the full path of sources to the contents of those sources.
+   * This is used to override the default contents of a source.
+   */
+  HashMap<String, String> _contentMap = new HashMap<String, String>();
+
+  /**
+   * A table mapping the full path of sources to the modification stamps of
+   * those sources. This is used when the default contents of a source has been
+   * overridden.
+   */
+  HashMap<String, int> _stampMap = new HashMap<String, int>();
+
+  /**
+   * Visit all entries of this cache.
+   */
+  void accept(ContentCacheVisitor visitor) {
+    _contentMap.forEach((String fullPath, String contents) {
+      int stamp = _stampMap[fullPath];
+      visitor(fullPath, stamp, contents);
+    });
+  }
+
+  /**
+   * Return the contents of the given [source], or `null` if this cache does not
+   * override the contents of the source.
+   *
+   * <b>Note:</b> This method is not intended to be used except by
+   * [AnalysisContext.getContents].
+   */
+  String getContents(Source source) => _contentMap[source.fullName];
+
+  /**
+   * Return the modification stamp of the given [source], or `null` if this
+   * cache does not override the contents of the source.
+   *
+   * <b>Note:</b> This method is not intended to be used except by
+   * [AnalysisContext.getModificationStamp].
+   */
+  int getModificationStamp(Source source) => _stampMap[source.fullName];
+
+  /**
+   * Set the contents of the given [source] to the given [contents]. This has
+   * the effect of overriding the default contents of the source. If the
+   * contents are `null` the override is removed so that the default contents
+   * will be returned.
+   */
+  String setContents(Source source, String contents) {
+    String fullName = source.fullName;
+    if (contents == null) {
+      _stampMap.remove(fullName);
+      return _contentMap.remove(fullName);
+    } else {
+      int newStamp = JavaSystem.currentTimeMillis();
+      int oldStamp = _stampMap[fullName];
+      _stampMap[fullName] = newStamp;
+      // Occasionally, if this method is called in rapid succession, the
+      // timestamps are equal. Guard against this by artificially incrementing
+      // the new timestamp.
+      if (newStamp == oldStamp) {
+        _stampMap[fullName] = newStamp + 1;
+      }
+      String oldContent = _contentMap[fullName];
+      _contentMap[fullName] = contents;
+      return oldContent;
+    }
+  }
+}
+
+class CustomUriResolver extends UriResolver {
+  final Map<String, String> _urlMappings;
+
+  CustomUriResolver(this._urlMappings);
+
+  @override
+  Source resolveAbsolute(Uri uri, [Uri actualUri]) {
+    String mapping = _urlMappings[uri.toString()];
+    if (mapping == null) return null;
+
+    Uri fileUri = new Uri.file(mapping);
+    if (!fileUri.isAbsolute) return null;
+
+    JavaFile javaFile = new JavaFile.fromUri(fileUri);
+    return new FileBasedSource(javaFile, actualUri != null ? actualUri : uri);
+  }
+}
+
+/**
+ * Instances of the class `DartUriResolver` resolve `dart` URI's.
+ */
+class DartUriResolver extends UriResolver {
+  /**
+   * The name of the `dart` scheme.
+   */
+  static String DART_SCHEME = "dart";
+
+  /**
+   * The prefix of a URI using the dart-ext scheme to reference a native code library.
+   */
+  static String _DART_EXT_SCHEME = "dart-ext:";
+
+  /**
+   * The Dart SDK against which URI's are to be resolved.
+   */
+  final DartSdk _sdk;
+
+  /**
+   * Initialize a newly created resolver to resolve Dart URI's against the given platform within the
+   * given Dart SDK.
+   *
+   * @param sdk the Dart SDK against which URI's are to be resolved
+   */
+  DartUriResolver(this._sdk);
+
+  /**
+   * Return the [DartSdk] against which URIs are to be resolved.
+   *
+   * @return the [DartSdk] against which URIs are to be resolved.
+   */
+  DartSdk get dartSdk => _sdk;
+
+  @override
+  Source resolveAbsolute(Uri uri, [Uri actualUri]) {
+    if (!isDartUri(uri)) {
+      return null;
+    }
+    return _sdk.mapDartUri(uri.toString());
+  }
+
+  /**
+   * Return `true` if the given URI is a `dart-ext:` URI.
+   *
+   * @param uriContent the textual representation of the URI being tested
+   * @return `true` if the given URI is a `dart-ext:` URI
+   */
+  static bool isDartExtUri(String uriContent) =>
+      uriContent != null && uriContent.startsWith(_DART_EXT_SCHEME);
+
+  /**
+   * Return `true` if the given URI is a `dart:` URI.
+   *
+   * @param uri the URI being tested
+   * @return `true` if the given URI is a `dart:` URI
+   */
+  static bool isDartUri(Uri uri) => DART_SCHEME == uri.scheme;
+}
+
+/**
+ * Instances of the class `LineInfo` encapsulate information about line and column information
+ * within a source file.
+ */
+class LineInfo {
+  /**
+   * An array containing the offsets of the first character of each line in the source code.
+   */
+  final List<int> _lineStarts;
+
+  /**
+   * The zero-based [_lineStarts] index resulting from the last call to
+   * [getLocation].
+   */
+  int _previousLine = 0;
+
+  /**
+   * Initialize a newly created set of line information to represent the data encoded in the given
+   * array.
+   *
+   * @param lineStarts the offsets of the first character of each line in the source code
+   */
+  LineInfo(this._lineStarts) {
+    if (_lineStarts == null) {
+      throw new IllegalArgumentException("lineStarts must be non-null");
+    } else if (_lineStarts.length < 1) {
+      throw new IllegalArgumentException("lineStarts must be non-empty");
+    }
+  }
+
+  /**
+   * Return the location information for the character at the given offset.
+   *
+   * @param offset the offset of the character for which location information is to be returned
+   * @return the location information for the character at the given offset
+   */
+  LineInfo_Location getLocation(int offset) {
+    var min = 0;
+    var max = _lineStarts.length - 1;
+
+    // Subsequent calls to [getLocation] are often for offsets near each other.
+    // To take advantage of that, we cache the index of the line start we found
+    // when this was last called. If the current offset is on that line or
+    // later, we'll skip those early indices completely when searching.
+    if (offset >= _lineStarts[_previousLine]) {
+      min = _previousLine;
+
+      // Before kicking off a full binary search, do a quick check here to see
+      // if the new offset is on that exact line.
+      if (min == _lineStarts.length - 1 || offset < _lineStarts[min + 1]) {
+        return new LineInfo_Location(min + 1, offset - _lineStarts[min] + 1);
+      }
+    }
+
+    // Binary search to fine the line containing this offset.
+    while (min < max) {
+      var midpoint = (max - min + 1) ~/ 2 + min;
+
+      if (_lineStarts[midpoint] > offset) {
+        max = midpoint - 1;
+      } else {
+        min = midpoint;
+      }
+    }
+
+    _previousLine = min;
+
+    return new LineInfo_Location(min + 1, offset - _lineStarts[min] + 1);
+  }
+}
+
+/**
+ * Instances of the class `Location` represent the location of a character as a line and
+ * column pair.
+ */
+class LineInfo_Location {
+  /**
+   * The one-based index of the line containing the character.
+   */
+  final int lineNumber;
+
+  /**
+   * The one-based index of the column containing the character.
+   */
+  final int columnNumber;
+
+  /**
+   * Initialize a newly created location to represent the location of the character at the given
+   * line and column position.
+   *
+   * @param lineNumber the one-based index of the line containing the character
+   * @param columnNumber the one-based index of the column containing the character
+   */
+  LineInfo_Location(this.lineNumber, this.columnNumber);
+}
+
+/**
+ * Instances of interface `LocalSourcePredicate` are used to determine if the given
+ * [Source] is "local" in some sense, so can be updated.
+ */
+abstract class LocalSourcePredicate {
+  /**
+   * Instance of [LocalSourcePredicate] that always returns `false`.
+   */
+  static final LocalSourcePredicate FALSE = new LocalSourcePredicate_FALSE();
+
+  /**
+   * Instance of [LocalSourcePredicate] that always returns `true`.
+   */
+  static final LocalSourcePredicate TRUE = new LocalSourcePredicate_TRUE();
+
+  /**
+   * Instance of [LocalSourcePredicate] that returns `true` for all [Source]s
+   * except of SDK.
+   */
+  static final LocalSourcePredicate NOT_SDK =
+      new LocalSourcePredicate_NOT_SDK();
+
+  /**
+   * Determines if the given [Source] is local.
+   *
+   * @param source the [Source] to analyze
+   * @return `true` if the given [Source] is local
+   */
+  bool isLocal(Source source);
+}
+
+class LocalSourcePredicate_FALSE implements LocalSourcePredicate {
+  @override
+  bool isLocal(Source source) => false;
+}
+
+class LocalSourcePredicate_NOT_SDK implements LocalSourcePredicate {
+  @override
+  bool isLocal(Source source) => source.uriKind != UriKind.DART_URI;
+}
+
+class LocalSourcePredicate_TRUE implements LocalSourcePredicate {
+  @override
+  bool isLocal(Source source) => true;
+}
+
+/**
+ * An implementation of an non-existing [Source].
+ */
+class NonExistingSource extends Source {
+  @override
+  final String fullName;
+
+  @override
+  final Uri uri;
+
+  final UriKind uriKind;
+
+  NonExistingSource(this.fullName, this.uri, this.uriKind);
+
+  @override
+  TimestampedData<String> get contents {
+    throw new UnsupportedOperationException('$fullName does not exist.');
+  }
+
+  @override
+  String get encoding {
+    throw new UnsupportedOperationException('$fullName does not exist.');
+  }
+
+  @override
+  int get hashCode => fullName.hashCode;
+
+  @override
+  bool get isInSystemLibrary => false;
+
+  @override
+  int get modificationStamp => -1;
+
+  @override
+  String get shortName => pathos.basename(fullName);
+
+  @override
+  bool operator ==(Object other) {
+    if (other is NonExistingSource) {
+      return other.uriKind == uriKind && other.fullName == fullName;
+    }
+    return false;
+  }
+
+  @override
+  bool exists() => false;
+
+  @override
+  Uri resolveRelativeUri(Uri relativeUri) {
+    throw new UnsupportedOperationException('$fullName does not exist.');
+  }
+}
+
+/**
+ * The interface `Source` defines the behavior of objects representing source code that can be
+ * analyzed by the analysis engine.
+ *
+ * Implementations of this interface need to be aware of some assumptions made by the analysis
+ * engine concerning sources:
+ * * Sources are not required to be unique. That is, there can be multiple instances representing
+ * the same source.
+ * * Sources are long lived. That is, the engine is allowed to hold on to a source for an extended
+ * period of time and that source must continue to report accurate and up-to-date information.
+ * Because of these assumptions, most implementations will not maintain any state but will delegate
+ * to an authoritative system of record in order to implement this API. For example, a source that
+ * represents files on disk would typically query the file system to determine the state of the
+ * file.
+ *
+ * If the instances that implement this API are the system of record, then they will typically be
+ * unique. In that case, sources that are created that represent non-existent files must also be
+ * retained so that if those files are created at a later date the long-lived sources representing
+ * those files will know that they now exist.
+ */
+abstract class Source implements AnalysisTarget {
+  /**
+   * An empty list of sources.
+   */
+  @deprecated // Use Source.EMPTY_LIST
+  static const List<Source> EMPTY_ARRAY = EMPTY_LIST;
+
+  /**
+   * An empty list of sources.
+   */
+  static const List<Source> EMPTY_LIST = const <Source>[];
+
+  /**
+   * Get the contents and timestamp of this source.
+   *
+   * Clients should consider using the the method [AnalysisContext.getContents]
+   * because contexts can have local overrides of the content of a source that the source is not
+   * aware of.
+   *
+   * @return the contents and timestamp of the source
+   * @throws Exception if the contents of this source could not be accessed
+   */
+  TimestampedData<String> get contents;
+
+  /**
+   * Return an encoded representation of this source that can be used to create a source that is
+   * equal to this source.
+   *
+   * @return an encoded representation of this source
+   * See [SourceFactory.fromEncoding].
+   */
+  String get encoding;
+
+  /**
+   * Return the full (long) version of the name that can be displayed to the user to denote this
+   * source. For example, for a source representing a file this would typically be the absolute path
+   * of the file.
+   *
+   * @return a name that can be displayed to the user to denote this source
+   */
+  String get fullName;
+
+  /**
+   * Return a hash code for this source.
+   *
+   * @return a hash code for this source
+   * See [Object.hashCode].
+   */
+  @override
+  int get hashCode;
+
+  /**
+   * Return `true` if this source is in one of the system libraries.
+   *
+   * @return `true` if this is in a system library
+   */
+  bool get isInSystemLibrary;
+
+  /**
+   * Return the modification stamp for this source, or a negative value if the
+   * source does not exist. A modification stamp is a non-negative integer with
+   * the property that if the contents of the source have not been modified
+   * since the last time the modification stamp was accessed then the same value
+   * will be returned, but if the contents of the source have been modified one
+   * or more times (even if the net change is zero) the stamps will be different.
+   *
+   * Clients should consider using the the method
+   * [AnalysisContext.getModificationStamp] because contexts can have local
+   * overrides of the content of a source that the source is not aware of.
+   */
+  int get modificationStamp;
+
+  /**
+   * Return a short version of the name that can be displayed to the user to denote this source. For
+   * example, for a source representing a file this would typically be the name of the file.
+   *
+   * @return a name that can be displayed to the user to denote this source
+   */
+  String get shortName;
+
+  @override
+  Source get source => this;
+
+  /**
+   * Return the URI from which this source was originally derived.
+   *
+   * @return the URI from which this source was originally derived
+   */
+  Uri get uri;
+
+  /**
+   * Return the kind of URI from which this source was originally derived. If this source was
+   * created from an absolute URI, then the returned kind will reflect the scheme of the absolute
+   * URI. If it was created from a relative URI, then the returned kind will be the same as the kind
+   * of the source against which the relative URI was resolved.
+   *
+   * @return the kind of URI from which this source was originally derived
+   */
+  UriKind get uriKind;
+
+  /**
+   * Return `true` if the given object is a source that represents the same source code as
+   * this source.
+   *
+   * @param object the object to be compared with this object
+   * @return `true` if the given object is a source that represents the same source code as
+   *         this source
+   * See [Object.==].
+   */
+  @override
+  bool operator ==(Object object);
+
+  /**
+   * Return `true` if this source exists.
+   *
+   * Clients should consider using the the method [AnalysisContext.exists] because
+   * contexts can have local overrides of the content of a source that the source is not aware of
+   * and a source with local content is considered to exist even if there is no file on disk.
+   *
+   * @return `true` if this source exists
+   */
+  bool exists();
+
+  /**
+   * Resolve the relative URI against the URI associated with this source object.
+   *
+   * Note: This method is not intended for public use, it is only visible out of necessity. It is
+   * only intended to be invoked by a [SourceFactory]. Source factories will
+   * only invoke this method if the URI is relative, so implementations of this method are not
+   * required to, and generally do not, verify the argument. The result of invoking this method with
+   * an absolute URI is intentionally left unspecified.
+   *
+   * @param relativeUri the relative URI to be resolved against this source
+   * @return the URI to which given URI was resolved
+   * @throws AnalysisException if the relative URI could not be resolved
+   */
+  Uri resolveRelativeUri(Uri relativeUri);
+}
+
+/**
+ * The interface `ContentReceiver` defines the behavior of objects that can receive the
+ * content of a source.
+ */
+abstract class Source_ContentReceiver {
+  /**
+   * Accept the contents of a source.
+   *
+   * @param contents the contents of the source
+   * @param modificationTime the time at which the contents were last set
+   */
+  void accept(String contents, int modificationTime);
+}
+
+/**
+ * The interface `SourceContainer` is used by clients to define a collection of sources
+ *
+ * Source containers are not used within analysis engine, but can be used by clients to group
+ * sources for the purposes of accessing composite dependency information. For example, the Eclipse
+ * client uses source containers to represent Eclipse projects, which allows it to easily compute
+ * project-level dependencies.
+ */
+abstract class SourceContainer {
+  /**
+   * Determine if the specified source is part of the receiver's collection of sources.
+   *
+   * @param source the source in question
+   * @return `true` if the receiver contains the source, else `false`
+   */
+  bool contains(Source source);
+}
+
+/**
+ * Instances of the class `SourceFactory` resolve possibly relative URI's against an existing
+ * [Source].
+ */
+class SourceFactory {
+  /**
+   * 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.
+   */
+  SourceFactory(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 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 object representing the URI that results from resolving the given (possibly
+   * relative) contained URI against the URI associated with an existing source object, whether or
+   * not the resulting source exists, or `null` if either the contained URI is invalid or if
+   * it cannot be resolved against the source object's URI.
+   *
+   * @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
+   */
+  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));
+    } catch (exception, stackTrace) {
+      String containingFullName =
+          containingSource != null ? containingSource.fullName : '<null>';
+      AnalysisEngine.instance.logger.logError(
+          "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 =
+          _packages.resolve(containedUri, notFound: (Uri packageUri) => null);
+
+      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;
+  }
+}
+
+/**
+ * The enumeration `SourceKind` defines the different kinds of sources that are known to the
+ * analysis engine.
+ */
+class SourceKind extends Enum<SourceKind> {
+  /**
+   * A source containing HTML. The HTML might or might not contain Dart scripts.
+   */
+  static const SourceKind HTML = const SourceKind('HTML', 0);
+
+  /**
+   * A Dart compilation unit that is not a part of another library. Libraries might or might not
+   * contain any directives, including a library directive.
+   */
+  static const SourceKind LIBRARY = const SourceKind('LIBRARY', 1);
+
+  /**
+   * A Dart compilation unit that is part of another library. Parts contain a part-of directive.
+   */
+  static const SourceKind PART = const SourceKind('PART', 2);
+
+  /**
+   * An unknown kind of source. Used both when it is not possible to identify the kind of a source
+   * and also when the kind of a source is not known without performing a computation and the client
+   * does not want to spend the time to identify the kind.
+   */
+  static const SourceKind UNKNOWN = const SourceKind('UNKNOWN', 3);
+
+  static const List<SourceKind> values = const [HTML, LIBRARY, PART, UNKNOWN];
+
+  const SourceKind(String name, int ordinal) : super(name, ordinal);
+}
+
+/**
+ * A source range defines an [Element]'s source coordinates relative to its [Source].
+ */
+class SourceRange {
+  /**
+   * An empty [SourceRange] with offset `0` and length `0`.
+   */
+  static SourceRange EMPTY = new SourceRange(0, 0);
+
+  /**
+   * The 0-based index of the first character of the source code for this element, relative to the
+   * source buffer in which this element is contained.
+   */
+  final int offset;
+
+  /**
+   * The number of characters of the source code for this element, relative to the source buffer in
+   * which this element is contained.
+   */
+  final int length;
+
+  /**
+   * Initialize a newly created source range using the given offset and the given length.
+   *
+   * @param offset the given offset
+   * @param length the given length
+   */
+  SourceRange(this.offset, this.length);
+
+  /**
+   * @return the 0-based index of the after-last character of the source code for this element,
+   *         relative to the source buffer in which this element is contained.
+   */
+  int get end => offset + length;
+
+  @override
+  int get hashCode => 31 * offset + length;
+
+  @override
+  bool operator ==(Object obj) {
+    if (obj is! SourceRange) {
+      return false;
+    }
+    SourceRange sourceRange = obj as SourceRange;
+    return sourceRange.offset == offset && sourceRange.length == length;
+  }
+
+  /**
+   * @return `true` if <code>x</code> is in [offset, offset + length) interval.
+   */
+  bool contains(int x) => offset <= x && x < offset + length;
+
+  /**
+   * @return `true` if <code>x</code> is in (offset, offset + length) interval.
+   */
+  bool containsExclusive(int x) => offset < x && x < offset + length;
+
+  /**
+   * @return `true` if <code>otherRange</code> covers this [SourceRange].
+   */
+  bool coveredBy(SourceRange otherRange) => otherRange.covers(this);
+
+  /**
+   * @return `true` if this [SourceRange] covers <code>otherRange</code>.
+   */
+  bool covers(SourceRange otherRange) =>
+      offset <= otherRange.offset && otherRange.end <= end;
+
+  /**
+   * @return `true` if this [SourceRange] ends in <code>otherRange</code>.
+   */
+  bool endsIn(SourceRange otherRange) {
+    int thisEnd = end;
+    return otherRange.contains(thisEnd);
+  }
+
+  /**
+   * @return the expanded instance of [SourceRange], which has the same center.
+   */
+  SourceRange getExpanded(int delta) =>
+      new SourceRange(offset - delta, delta + length + delta);
+
+  /**
+   * @return the instance of [SourceRange] with end moved on "delta".
+   */
+  SourceRange getMoveEnd(int delta) => new SourceRange(offset, length + delta);
+
+  /**
+   * @return the expanded translated of [SourceRange], with moved start and the same length.
+   */
+  SourceRange getTranslated(int delta) =>
+      new SourceRange(offset + delta, length);
+
+  /**
+   * @return the minimal [SourceRange] that cover this and the given [SourceRange]s.
+   */
+  SourceRange getUnion(SourceRange other) {
+    int newOffset = math.min(offset, other.offset);
+    int newEnd = math.max(offset + length, other.offset + other.length);
+    return new SourceRange(newOffset, newEnd - newOffset);
+  }
+
+  /**
+   * @return `true` if this [SourceRange] intersects with given.
+   */
+  bool intersects(SourceRange other) {
+    if (other == null) {
+      return false;
+    }
+    if (end <= other.offset) {
+      return false;
+    }
+    if (offset >= other.end) {
+      return false;
+    }
+    return true;
+  }
+
+  /**
+   * Return `true` if this [SourceRange] starts in the [otherRange].
+   */
+  bool startsIn(SourceRange otherRange) => otherRange.contains(offset);
+
+  @override
+  String toString() => '[offset=$offset, length=$length]';
+}
+
+/**
+ * The enumeration `UriKind` defines the different kinds of URI's that are known to the
+ * analysis engine. These are used to keep track of the kind of URI associated with a given source.
+ */
+class UriKind extends Enum<UriKind> {
+  /**
+   * A 'dart:' URI.
+   */
+  static const UriKind DART_URI = const UriKind('DART_URI', 0, 0x64);
+
+  /**
+   * A 'file:' URI.
+   */
+  static const UriKind FILE_URI = const UriKind('FILE_URI', 1, 0x66);
+
+  /**
+   * A 'package:' URI.
+   */
+  static const UriKind PACKAGE_URI = const UriKind('PACKAGE_URI', 2, 0x70);
+
+  static const List<UriKind> values = const [DART_URI, FILE_URI, PACKAGE_URI];
+
+  /**
+   * The single character encoding used to identify this kind of URI.
+   */
+  final int encoding;
+
+  /**
+   * Initialize a newly created URI kind to have the given encoding.
+   *
+   * @param encoding the single character encoding used to identify this kind of URI.
+   */
+  const UriKind(String name, int ordinal, this.encoding) : super(name, ordinal);
+
+  /**
+   * Return the URI kind represented by the given encoding, or `null` if there is no kind with
+   * the given encoding.
+   *
+   * @param encoding the single character encoding used to identify the URI kind to be returned
+   * @return the URI kind represented by the given encoding
+   */
+  static UriKind fromEncoding(int encoding) {
+    while (true) {
+      if (encoding == 0x64) {
+        return DART_URI;
+      } else if (encoding == 0x66) {
+        return FILE_URI;
+      } else if (encoding == 0x70) {
+        return PACKAGE_URI;
+      }
+      break;
+    }
+    return null;
+  }
+}
+
+/**
+ * The abstract class `UriResolver` defines the behavior of objects that are used to resolve
+ * URI's for a source factory. Subclasses of this class are expected to resolve a single scheme of
+ * absolute URI.
+ */
+abstract class UriResolver {
+  /**
+   * Resolve the given absolute URI. Return a [Source] representing the file to which
+   * it was resolved, whether or not the resulting source exists, or `null` if it could not be
+   * resolved because the URI is invalid.
+   *
+   * @param uri the URI to be resolved
+   * @param actualUri the actual uri for this source -- if `null`, the value of [uri] will be used
+   * @return a [Source] representing the file to which given URI was resolved
+   */
+  Source resolveAbsolute(Uri uri, [Uri actualUri]);
+
+  /**
+   * Return an absolute URI that represents the given [source], or `null` if a
+   * valid URI cannot be computed.
+   *
+   * The computation should be based solely on [source.fullName].
+   */
+  Uri restoreAbsolute(Source source) => null;
+}