Move frog/leg to lib/compiler/implementation.

frog/leg/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';
-
-  void scan(CompilationUnitElement compilationUnit) {
-    measure(() {
-      if (compilationUnit.kind === ElementKind.LIBRARY) {
-        compiler.log("scanning library ${compilationUnit.script.name}");
-      }
-      scanElements(compilationUnit);
-      if (compilationUnit.kind === ElementKind.LIBRARY) {
-        processScriptTags(compilationUnit);
-      }
-    });
-  }
-
-  void processScriptTags(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, ScriptTag tag) {
-      if (tagState > value) {
-        compiler.reportError(tag, 'out of order');
-        return tagState;
-      }
-      return TagState.NEXT[value];
-    }
-
-    LinkBuilder<ScriptTag> imports = new LinkBuilder<ScriptTag>();
-    Uri cwd = new Uri(scheme: 'file', path: compiler.currentDirectory);
-    Uri base = cwd.resolve(library.script.name.toString());
-    for (ScriptTag tag in library.tags.reverse()) {
-      StringNode argument = tag.argument;
-      // TODO(lrn): Support interpolations here. We need access to the
-      // special constants that can be inserted into script tag strings.
-      Uri resolved = base.resolve(argument.dartString.slowToString());
-      if (tag.isImport()) {
-        tagState = checkTag(TagState.IMPORT, tag);
-        // 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.isLibrary()) {
-        tagState = checkTag(TagState.LIBRARY, tag);
-        if (library.libraryTag !== null) {
-          compiler.cancel("duplicated library declaration", node: tag);
-        } else {
-          library.libraryTag = tag;
-        }
-      } else if (tag.isSource()) {
-        tagState = checkTag(TagState.SOURCE, tag);
-        Script script = compiler.readScript(resolved, tag);
-        CompilationUnitElement unit =
-          new CompilationUnitElement(script, library);
-        compiler.withCurrentElement(unit, () => scan(unit));
-      } else if (tag.isResource()) {
-        tagState = checkTag(TagState.RESOURCE, tag);
-        compiler.reportWarning(tag, 'ignoring resource tag');
-      } else {
-        compiler.cancel("illegal script tag: ${tag.tag}", node: tag);
-      }
-    }
-    // TODO(ahe): During Compiler.scanBuiltinLibraries,
-    // compiler.coreLibrary is null. Clean this up when there is a
-    // better way to access "dart:core".
-    bool implicitlyImportCoreLibrary = compiler.coreLibrary !== null;
-    for (ScriptTag tag in imports.toLink()) {
-      // Now that we have processed all the source tags, it is safe to
-      // start loading other libraries.
-      StringNode argument = tag.argument;
-      Uri resolved = base.resolve(argument.dartString.slowToString());
-      if (resolved.toString() == "dart:core") {
-        implicitlyImportCoreLibrary = false;
-      }
-      importLibrary(library, loadLibrary(resolved, tag), tag);
-    }
-    if (implicitlyImportCoreLibrary) {
-      importLibrary(library, compiler.coreLibrary, null);
-    }
-  }
-
-  void scanElements(CompilationUnitElement compilationUnit) {
-    Script script = compilationUnit.script;
-    Token tokens;
-    try {
-      tokens = new StringScanner(script.text).tokenize();
-    } catch (MalformedInputException ex) {
-      Token token;
-      var message;
-      if (ex.position is num) {
-        // TODO(ahe): Always use tokens in MalformedInputException.
-        token = new Token(EOF_INFO, ex.position);
-      } else {
-        token = ex.position;
-      }
-      compiler.cancel(ex.message, token: token);
-    }
-    compiler.dietParser.dietParse(compilationUnit, tokens);
-  }
-
-  LibraryElement loadLibrary(Uri uri, ScriptTag node) {
-    bool newLibrary = false;
-    LibraryElement library =
-      compiler.universe.libraries.putIfAbsent(uri.toString(), () {
-          newLibrary = true;
-          Script script = compiler.readScript(uri, node);
-          LibraryElement element = new LibraryElement(script);
-          native.maybeEnableNative(compiler, element, uri);
-          return element;
-        });
-    if (newLibrary) {
-      compiler.withCurrentElement(library, () => scan(library));
-      compiler.onLibraryLoaded(library, uri);
-    }
-    return library;
-  }
-
-  void importLibrary(LibraryElement library, LibraryElement imported,
-                     ScriptTag tag) {
-    if (!imported.hasLibraryName()) {
-      compiler.withCurrentElement(library, () {
-        compiler.reportError(tag,
-                             'no #library tag found in ${imported.script.uri}');
-      });
-    }
-    if (tag !== null && tag.prefix !== null) {
-      SourceString prefix =
-          new SourceString(tag.prefix.dartString.slowToString());
-      Element e = library.find(prefix);
-      if (e === null) {
-        e = new PrefixElement(prefix, library, tag.getBeginToken());
-        library.define(e, compiler);
-      }
-      if (e.kind !== ElementKind.PREFIX) {
-        compiler.withCurrentElement(e, () {
-          compiler.reportWarning(new Identifier(e.position()),
-                                 'duplicated definition');
-        });
-        compiler.reportError(tag.prefix, 'duplicate defintion');
-      }
-      imported.forEachExport((Element element) {
-        Element existing = e.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.define(element, compiler);
-        });
-      });
-    }
-  }
-}
-
-class DietParserTask extends CompilerTask {
-  DietParserTask(Compiler compiler) : super(compiler);
-  final String name = 'Diet Parser';
-
-  dietParse(CompilationUnitElement compilationUnit, Token tokens) {
-    measure(() {
-      ElementListener listener = new ElementListener(compiler, compilationUnit);
-      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 final int NO_TAG_SEEN = 0;
-  static final int LIBRARY = 1;
-  static final int IMPORT = 2;
-  static final int SOURCE = 3;
-  static final int RESOURCE = 4;
-
-  /** Next state. */
-  static final List<int> NEXT =
-      const <int>[NO_TAG_SEEN,
-                  IMPORT, // Only one library tag is allowed.
-                  IMPORT,
-                  SOURCE,
-                  RESOURCE];
-}