Added support for exports and re-exports.

lib/compiler/implementation/scanner/scanner_task.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.
 
 class ScannerTask extends CompilerTask {
   ScannerTask(Compiler compiler) : super(compiler);
   String get name => 'Scanner';
 
-  final Map<String, LibraryElement> libraryNames =
-      new Map<String, LibraryElement>();
-
   void scanLibrary(LibraryElement library) {
     var compilationUnit = library.entryCompilationUnit;
     compiler.log("scanning library ${compilationUnit.script.name}");
     scan(compilationUnit);
-    processLibraryTags(library);
   }
 
   void scan(CompilationUnitElement compilationUnit) {
     measure(() {
       scanElements(compilationUnit);
     });
   }
 
-  void processLibraryTags(LibraryElement library) {
-    int tagState = TagState.NO_TAG_SEEN;
-
-    /**
-     * If [value] is less than [tagState] complain and return
-     * [tagState]. Otherwise return the new value for [tagState]
-     * (transition function for state machine).
-     */
-    int checkTag(int value, LibraryTag tag) {
-      if (tagState > value) {
-        compiler.reportError(tag, 'out of order');
-        return tagState;
-      }
-      return TagState.NEXT[value];
-    }
-
-    LinkBuilder<Import> imports = new LinkBuilder<Import>();
-    Uri base = library.entryCompilationUnit.script.uri;
-    for (LibraryTag tag in library.tags.reverse()) {
-      if (tag.isImport) {
-        tagState = checkTag(TagState.IMPORT, tag);
-        if (tag.combinators != null) {
-          compiler.unimplemented('combinators', node: tag.combinators);
-        }
-        // It is not safe to import other libraries at this point as
-        // another library could then observe the current library
-        // before it fully declares all the members that are sourced
-        // in.
-        imports.addLast(tag);
-      } else if (tag.isLibraryName) {
-        tagState = checkTag(TagState.LIBRARY, tag);
-        if (library.libraryTag !== null) {
-          compiler.cancel("duplicated library declaration", node: tag);
-        } else {
-          library.libraryTag = tag;
-        }
-        checkDuplicatedLibraryName(library);
-      } else if (tag.isPart) {
-        StringNode uri = tag.uri;
-        Uri resolved = base.resolve(uri.dartString.slowToString());
-        tagState = checkTag(TagState.SOURCE, tag);
-        loadPart(tag, resolved, library);
-      } else {
-        compiler.internalError("Unhandled library tag.", node: tag);
-      }
-    }
-
-    // Apply patch, if any.
-    if (library.uri.scheme == 'dart') {
-      compiler.patchDartLibrary(library, library.uri.path);
-    }
-
-    // Now that we have processed all the source tags, it is safe to
-    // start loading other libraries.
-
-    if (library.uri.scheme != 'dart' || library.uri.path != 'core') {
-      compiler.importCoreLibrary(library);
-    }
-
-    for (Import tag in imports.toLink()) {
-      importLibraryFromTag(tag, library.entryCompilationUnit);
-    }
-  }
-
-  void checkDuplicatedLibraryName(LibraryElement library) {
-    LibraryTag tag = library.libraryTag;
-    if (tag != null) {
-      String name = library.getLibraryOrScriptName();
-      LibraryElement existing =
-          libraryNames.putIfAbsent(name, () => library);
-      if (existing !== library) {
-        Uri uri = library.entryCompilationUnit.script.uri;
-        compiler.reportMessage(
-            compiler.spanFromNode(tag.name, uri),
-            MessageKind.DUPLICATED_LIBRARY_NAME.error([name]),
-            api_s.Diagnostic.WARNING);
-        Uri existingUri = existing.entryCompilationUnit.script.uri;
-        compiler.reportMessage(
-            compiler.spanFromNode(existing.libraryTag.name, existingUri),
-            MessageKind.DUPLICATED_LIBRARY_NAME.error([name]),
-            api_s.Diagnostic.WARNING);
-      }
-    }
-  }
-
-  /**
-   * Handle a part tag in the scope of [library]. The [path] given is used as
-   * is, any resolution should be done beforehand.
-   */
-  void loadPart(Part part, Uri path, LibraryElement library) {
-    Script sourceScript = compiler.readScript(path, part.uri);
-    CompilationUnitElement unit =
-        new CompilationUnitElement(sourceScript, library);
-    compiler.withCurrentElement(unit, () => compiler.scanner.scan(unit));
-  }
-
-  /**
-   * Handle an import script tag by importing the referenced library into the
-   * current library.
-   * Returns the resolved library [Uri].
-   */
-  Uri importLibraryFromTag(Import tag,
-                           CompilationUnitElement compilationUnit) {
-    Uri base = compilationUnit.script.uri;
-    Uri resolved = base.resolve(tag.uri.dartString.slowToString());
-    LibraryElement importedLibrary = loadLibrary(resolved, tag.uri, resolved);
-    importLibrary(compilationUnit.getLibrary(),
-                  importedLibrary,
-                  tag,
-                  compilationUnit);
-    return resolved;
-  }
-
   void scanElements(CompilationUnitElement compilationUnit) {
     Script script = compilationUnit.script;
     Token tokens = new StringScanner(script.text).tokenize();
     compiler.dietParser.dietParse(compilationUnit, tokens);
   }
-
-  LibraryElement loadLibrary(Uri uri, Node node, Uri canonicalUri) {
-    bool newLibrary = false;
-    LibraryElement createLibrary() {
-      newLibrary = true;
-      Script script = compiler.readScript(uri, node);
-      LibraryElement element = new LibraryElement(script, canonicalUri);
-      native.maybeEnableNative(compiler, element, uri);
-      return element;
-    }
-    LibraryElement library;
-    if (canonicalUri === null) {
-      library = createLibrary();
-    } else {
-      library = compiler.libraries.putIfAbsent(canonicalUri.toString(),
-                                               createLibrary);
-    }
-    if (newLibrary) {
-      compiler.withCurrentElement(library, () {
-        scanLibrary(library);
-        compiler.onLibraryLoaded(library, uri);
-      });
-    }
-    return library;
-  }
-
-  void importLibrary(LibraryElement library, LibraryElement imported,
-                     Import tag, [CompilationUnitElement compilationUnit]) {
-    if (!imported.hasLibraryName()) {
-      compiler.withCurrentElement(library, () {
-        compiler.reportError(tag === null ? null : tag.uri,
-                             'no #library tag found in ${imported.uri}');
-      });
-    }
-    if (tag !== null && tag.prefix !== null) {
-      SourceString prefix = tag.prefix.source;
-      Element e = library.find(prefix);
-      if (e === null) {
-        if (compilationUnit === null) {
-          compilationUnit = library.entryCompilationUnit;
-        }
-        e = new PrefixElement(prefix, compilationUnit, tag.getBeginToken());
-        library.addToScope(e, compiler);
-      }
-      if (e.kind !== ElementKind.PREFIX) {
-        compiler.withCurrentElement(e, () {
-          compiler.reportWarning(new Identifier(e.position()),
-                                 'duplicated definition');
-        });
-        compiler.reportError(tag.prefix, 'duplicate defintion');
-      }
-      PrefixElement prefixElement = e;
-      imported.forEachExport((Element element) {
-        Element existing =
-            prefixElement.imported.putIfAbsent(element.name, () => element);
-        if (existing !== element) {
-          compiler.withCurrentElement(existing, () {
-            compiler.reportWarning(new Identifier(existing.position()),
-                                   'duplicated import');
-          });
-          compiler.withCurrentElement(element, () {
-            compiler.reportError(new Identifier(element.position()),
-                                 'duplicated import');
-          });
-        }
-      });
-    } else {
-      imported.forEachExport((Element element) {
-        compiler.withCurrentElement(element, () {
-          library.addImport(element, compiler);
-        });
-      });
-    }
-  }
 }
 
 class DietParserTask extends CompilerTask {
   DietParserTask(Compiler compiler) : super(compiler);
   final String name = 'Diet Parser';
 
   dietParse(CompilationUnitElement compilationUnit, Token tokens) {
     measure(() {
       Function idGenerator = compiler.getNextFreeClassId;
       ElementListener listener =
           new ElementListener(compiler, compilationUnit, idGenerator);
       PartialParser parser = new PartialParser(listener);
       parser.parseUnit(tokens);
     });
   }
 }
-
-/**
- * The fields of this class models a state machine for checking script
- * tags come in the correct order.
- */
-class TagState {
-  static const int NO_TAG_SEEN = 0;
-  static const int LIBRARY = 1;
-  static const int IMPORT = 2;
-  static const int SOURCE = 3;
-  static const int RESOURCE = 4;
-
-  /** Next state. */
-  static const List<int> NEXT =
-      const <int>[NO_TAG_SEEN,
-                  IMPORT, // Only one library tag is allowed.
-                  IMPORT,
-                  SOURCE,
-                  RESOURCE];
-}