Remove backends.

compiler/java/com/google/dart/compiler/backend/js/AbstractJsBackend.java

Index: compiler/java/com/google/dart/compiler/backend/js/AbstractJsBackend.java
diff --git a/compiler/java/com/google/dart/compiler/backend/js/AbstractJsBackend.java b/compiler/java/com/google/dart/compiler/backend/js/AbstractJsBackend.java
deleted file mode 100644
index 231c1e9b6c8349dd9244097ef6c15666a355ccc5..0000000000000000000000000000000000000000
--- a/compiler/java/com/google/dart/compiler/backend/js/AbstractJsBackend.java
+++ /dev/null
@@ -1,518 +0,0 @@
-// Copyright (c) 2011, 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.
-
-package com.google.dart.compiler.backend.js;
-
-import com.google.common.collect.ArrayListMultimap;
-import com.google.common.collect.HashMultimap;
-import com.google.common.collect.HashMultiset;
-import com.google.common.collect.Lists;
-import com.google.common.collect.Maps;
-import com.google.common.collect.Multimap;
-import com.google.common.collect.Multimaps;
-import com.google.common.collect.Multiset;
-import com.google.common.io.Closeables;
-import com.google.dart.compiler.Backend;
-import com.google.dart.compiler.CommandLineOptions.CompilerOptions;
-import com.google.dart.compiler.DartCompilerContext;
-import com.google.dart.compiler.DartSource;
-import com.google.dart.compiler.ast.DartClass;
-import com.google.dart.compiler.ast.DartNode;
-import com.google.dart.compiler.ast.DartUnit;
-import com.google.dart.compiler.ast.LibraryNode;
-import com.google.dart.compiler.ast.LibraryUnit;
-import com.google.dart.compiler.backend.js.ast.JsBlock;
-import com.google.dart.compiler.backend.js.ast.JsProgram;
-import com.google.dart.compiler.metrics.DartEventType;
-import com.google.dart.compiler.metrics.Tracer.TraceEvent;
-import com.google.dart.compiler.metrics.Tracer;
-import com.google.dart.compiler.resolver.ClassElement;
-import com.google.dart.compiler.resolver.CoreTypeProvider;
-import com.google.dart.compiler.resolver.MethodElement;
-import com.google.dart.compiler.type.InterfaceType;
-import com.google.dart.compiler.util.DefaultTextOutput;
-import com.google.dart.compiler.util.TextOutput;
-
-import java.io.IOException;
-import java.io.Writer;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Comparator;
-import java.util.HashSet;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.PriorityQueue;
-import java.util.Set;
-
-/**
- * Methods common to the ClosureJsBackend and JavascriptBackend.
- * @author johnlenz@google.com (John Lenz)
- */
-public abstract class AbstractJsBackend implements Backend {
-
-  public static final String EXTENSION_JS = "js";
-  public static final String EXTENSION_APP_JS = "app.js";
-
-  private static final String ROOT_PART_NAME = "";
-  private static final String STATICS_PART_NAME = "$statics$";
-  private static final String SEPARATOR_PART_NAME = "$seperator$";
-
-  protected final DartMangler mangler = new DollarMangler();
-
-  protected static class Part {
-    final LibraryUnit lib;
-    final DartUnit unit;
-    final String part;
-    final ClassElement element;
-    final ClassElement superElement;
-
-    public Part(LibraryUnit lib, DartUnit unit, String part,
-                ClassElement element, ClassElement superElement) {
-      this.lib = lib;
-      this.unit = unit;
-      this.element = element;
-      this.part = part;
-      this.superElement = superElement;
-    }
-
-    @Override
-    public int hashCode() {
-      if (element != null) {
-        return element.hashCode();
-      }
-      final int prime = 31;
-      int result = 1;
-      result = prime * result + ((part == null) ? 0 : part.hashCode());
-      result = prime * result + ((unit == null) ? 0 : unit.hashCode());
-      return result;
-    }
-
-    @Override
-    public boolean equals(Object obj) {
-      if (this == obj) {
-        return true;
-      }
-      if (obj == null) {
-        return false;
-      }
-      if (getClass() != obj.getClass()) {
-        return false;
-      }
-      Part other = (Part) obj;
-      if (element != null) {
-        return element.equals(other.element);
-      }
-      return unit.equals(other.unit) && part.equals(other.part);
-    }
-  }
-
-  protected static interface DepsCallback {
-    void visitNative(LibraryUnit libUnit, LibraryNode node) throws IOException;
-    void visitPart(Part part) throws IOException;
-  }
-
-  protected static class DependencyBuilder {
-    private final List<Part> parts;
-    private final Part staticSeparator = new Part(null, null, SEPARATOR_PART_NAME, null, null);
-
-    static void build(LibraryUnit libUnit, DepsCallback callback) throws IOException {
-      DependencyBuilder builder = new DependencyBuilder();
-      builder.gatherParts(libUnit);
-      builder.sortParts();
-      builder.writeParts(callback);
-    }
-
-    private DependencyBuilder() {
-      this.parts = new ArrayList<Part>();
-    }
-
-    private void gatherParts(LibraryUnit libUnit) {
-      gatherParts(libUnit, new HashSet<LibraryUnit>());
-    }
-
-    private void gatherParts(LibraryUnit libUnit, Set<LibraryUnit> seenLibs) {
-      // Avoid cycles.
-      if (seenLibs.contains(libUnit)) {
-        return;
-      }
-      seenLibs.add(libUnit);
-
-      // Visit dependencies first.
-      for (LibraryUnit importUnit : libUnit.getImports()) {
-        gatherParts(importUnit, seenLibs);
-      }
-
-      for (DartUnit unit : libUnit.getUnits()) {
-        DartSource src = unit.getSource();
-        if (src != null) {
-          // get the list of source source parts
-          gatherUnitParts(libUnit, unit);
-        }
-      }
-    }
-
-    private void gatherUnitParts(LibraryUnit libUnit, DartUnit unit) {
-      List<DartNode> nodes = ((DartUnit)unit.getNormalizedNode()).getTopLevelNodes();
-      for (DartNode node : nodes) {
-        DartNode norm = node.getNormalizedNode();
-        if (norm instanceof DartClass) {
-          DartClass clasz = (DartClass)norm;
-          ClassElement selfElement = clasz.getSymbol();
-          InterfaceType superType = selfElement.getSupertype();
-          ClassElement superElement = null;
-          if (superType != null) {
-            superElement = superType.getElement();
-            assert(superElement != null);
-          }
-
-          parts.add(new Part(libUnit, unit,
-                             clasz.getClassName(), selfElement, superElement));
-        }
-      }
-
-      parts.add(new Part(libUnit, unit, ROOT_PART_NAME, null, null)); // top-level bits
-      parts.add(new Part(libUnit, unit, STATICS_PART_NAME, null, null)); // static initializer bits
-    }
-
-    /**
-     * @param items The list of items to sort.
-     * @param deps A map of dependencies between items.
-     * @return A list of items in dependency order.
-     */
-    private static <T> List<T> topologicalStableSort(
-        List<T> items, Multimap<T, T> deps) {
-      final Map<T, Integer> originalIndex = Maps.newHashMap();
-      for (int i = 0; i < items.size(); i++) {
-        originalIndex.put(items.get(i), i);
-      }
-
-      PriorityQueue<T> inDegreeZero = new PriorityQueue<T>(items.size(),
-          new Comparator<T>() {
-        @Override
-        public int compare(T a, T b) {
-          return originalIndex.get(a).intValue() -
-              originalIndex.get(b).intValue();
-        }
-      });
-      List<T> result = Lists.newArrayList();
-
-      Multiset<T> inDegree = HashMultiset.create();
-      Multimap<T, T> reverseDeps = ArrayListMultimap.create();
-      Multimaps.invertFrom(deps, reverseDeps);
-
-      // First, add all the inputs with in-degree 0.
-      for (T item : items) {
-        Collection<T> itemDeps = deps.get(item);
-        inDegree.add(item, itemDeps.size());
-        if (itemDeps.isEmpty()) {
-          inDegreeZero.add(item);
-        }
-      }
-
-      // Then, iterate to a fixed point over the reverse dependency graph.
-      while (!inDegreeZero.isEmpty()) {
-        T item = inDegreeZero.remove();
-        result.add(item);
-        for (T inWaiting : reverseDeps.get(item)) {
-          inDegree.remove(inWaiting, 1);
-          if (inDegree.count(inWaiting) == 0) {
-            inDegreeZero.add(inWaiting);
-          }
-        }
-      }
-
-      return result;
-    }
-
-    /**
-     * Build a map of dependencies between Parts.
-     * @param parts The parts to build dependencies from.
-     */
-    private Multimap<Part, Part> buildDependencyMap(List<Part> parts) {
-      // Add a Part to act as separator between class initialization
-      // and static initialization. Statics may depend on the classes
-      // being properly setup.
-      parts.add(staticSeparator);
-
-      final Map<ClassElement, Part> elementToPartMap = Maps.newHashMap();
-      for (Part part : parts) {
-        if (part.element != null) {
-          Part previous = elementToPartMap.put(part.element, part);
-          assert(previous == null);
-        }
-      }
-
-      // Get the direct dependencies.
-      final Multimap<Part, Part> deps = HashMultimap.create();
-      for (Part part : parts) {
-        if (part.superElement != null) {
-          Part superPart = elementToPartMap.get(part.superElement);
-          assert(superPart != null);
-          deps.put(part, superPart);
-        }
-
-        // Don't add a dependency on itself.
-        if (part != staticSeparator) {
-          if (part.part.equals(STATICS_PART_NAME)) {
-            // Push all statics after classes.
-            deps.put(part, staticSeparator);
-          } else {
-            // All classes before statics.
-            deps.put(staticSeparator, part);
-          }
-        }
-      }
-      return deps;
-    }
-
-    /**
-     * Sort the parts based on their dependencies.
-     */
-    private void sortParts() {
-      List<Part> unsortedParts = parts;
-
-      Multimap<Part, Part> deps = buildDependencyMap(unsortedParts);
-      List<Part> sortParts = topologicalStableSort(unsortedParts, deps);
-
-      parts.clear();
-      parts.addAll(sortParts);
-    }
-
-    private long writeParts(DepsCallback callback)
-        throws IOException {
-      long charsWritten = 0;
-      Set<LibraryUnit> seenLibs = new HashSet<LibraryUnit>();
-      for (Part part : parts) {
-        writePart(part, callback, seenLibs);
-      }
-      return charsWritten;
-    }
-
-    private void writePart(Part part, DepsCallback callback, Set<LibraryUnit> seenLibs)
-        throws IOException {
-
-      // Don't try to do anything with the fake separator part.
-      if (part == staticSeparator) {
-        return;
-      }
-
-      // Avoid cycles.
-      if (!seenLibs.contains(part.lib)) {
-        seenLibs.add(part.lib);
-        // Prepend all native JS for this library.
-        for (LibraryNode node : part.lib.getNativePaths()) {
-          callback.visitNative(part.lib, node);
-        }
-      }
-
-      callback.visitPart(part);
-    }
-  }
-
-  protected Map<String, JsProgram> translateToJS(DartUnit unit, DartCompilerContext context,
-      CoreTypeProvider typeProvider) {
-    TraceEvent logEvent =
-        Tracer.canTrace() ? Tracer.start(DartEventType.TRANSLATE_TO_JS, "unit",
-            unit.getSourceName()) : null;
-
-     try {
-      TraceEvent normalizeEvent =
-          Tracer.canTrace() ? Tracer.start(DartEventType.JS_NORMALIZE, "unit",
-              unit.getSourceName()) : null;
-      try {
-        // Normalize front-end AST for back-end consumption.
-        unit = (DartUnit) (new Normalizer()).exec(unit, typeProvider).getNormalizedNode();
-      } finally {
-        Tracer.end(normalizeEvent);
-      }
-
-      // TODO(floitsch.: Make namer configurable.
-      JsNamer namer = new JsPrettyNamer();
-
-      Map<String, JsProgram> parts = new LinkedHashMap<String, JsProgram>();
-
-      List<DartNode> topNodes = unit.getTopLevelNodes();
-
-      // Generate an id for this unit that can be used to make globally unique
-      // identifiers.
-      String baseUnitId = generateBaseUnitId(unit);
-      int partIndex = 0;
-
-      // Translate the AST to JS.
-      JsProgram nonClassStatements = new JsProgram(baseUnitId + partIndex++);
-      GenerateJavascriptAST nonClassGenerator = null;
-      TranslationContext nonClassTranslationContext = null;
-
-      JsProgram staticInitStatements = new JsProgram(baseUnitId + partIndex++);
-      JsBlock staticInitBlock = staticInitStatements.getGlobalBlock();
-
-      for (DartNode node : topNodes) {
-        node = node.getNormalizedNode();
-        if (node instanceof DartClass) {
-          // TODO: Don't write out *.js for interfaces -- there are a lot of them
-          TraceEvent nodeEvent =
-              Tracer.canTrace() ? Tracer.start(DartEventType.TRANSLATE_NODE, "unit",
-                  unit.getSourceName(), "node", node.getSymbol().getOriginalSymbolName()) : null;
-          try {
-            // Translate the AST to JS.
-            JsProgram program = new JsProgram(baseUnitId + partIndex++);
-
-            TranslationContext translationContext = TranslationContext.createContext(unit, program,
-                mangler, node);
-
-            // Generate the Javascript AST.
-            GenerateJavascriptAST generator =
-                new GenerateJavascriptAST(unit, typeProvider, context);
-            generator.translateNode(translationContext, node, staticInitBlock);
-
-            TraceEvent namerEvent =
-                Tracer.canTrace() ? Tracer.start(DartEventType.NAMER, "unit",
-                    unit.getSourceName()) : null;
-            try {
-              namer.exec(program);
-            } finally {
-              Tracer.end(namerEvent);
-            }
-
-            parts.put(((DartClass) node).getClassName(), program);
-          } finally {
-            Tracer.end(nodeEvent);
-          }
-        } else {
-
-          if (nonClassGenerator == null) {
-            // This block generates the AST used to generate for all non-class nodes at once
-            // and is saved for subsequent iterations.
-            TraceEvent genInitEvent =
-                Tracer.canTrace() ? Tracer.start(DartEventType.GEN_AST_INIT, "unit",
-                    unit.getSourceName()) : null;
-            try {
-              nonClassTranslationContext = TranslationContext.createContext(unit,
-                  nonClassStatements, mangler, null);
-              nonClassGenerator = new GenerateJavascriptAST(unit, typeProvider, context);
-            } finally {
-              Tracer.end(genInitEvent);
-            }
-          }
-
-          nonClassGenerator.translateNode(nonClassTranslationContext, node, staticInitBlock);
-        }
-      }
-
-      TraceEvent namerEvent =
-          Tracer.canTrace() ? Tracer.start(DartEventType.NAMER, "unit", unit.getSourceName())
-              : null;
-      try {
-        namer.exec(nonClassStatements);
-      } finally {
-        Tracer.end(namerEvent);
-      }
-
-      // Out-of-date checks rely on the root JS file existing, even if it is empty
-      parts.put(ROOT_PART_NAME, nonClassStatements);
-
-      // Only add static parts if they are not empty
-      for (int i = 0; i < staticInitStatements.getFragmentCount(); ++i) {
-        if (!staticInitStatements.getFragmentBlock(i).getStatements().isEmpty()) {
-          parts.put(STATICS_PART_NAME, staticInitStatements);
-          break;
-        }
-      }
-
-      return parts;
-    } finally {
-      Tracer.end(logEvent);
-    }
-  }
-
-  private static String generateBaseUnitId(DartUnit unit) {
-    MessageDigest md;
-    try {
-      md = MessageDigest.getInstance("MD5");
-    } catch (NoSuchAlgorithmException e) {
-      throw new AssertionError("Could not find MD5 digest");
-    }
-    StringBuilder sb = new StringBuilder();
-    byte[] md5 = md.digest(unit.getSource().getUri().toString().getBytes());
-    // Only use the first 6 hex characters of the md5.
-    for (int i = 0; i < 3; i++) {
-      sb.append(Integer.toHexString((md5[i] & 0xf0) >> 4));
-      sb.append(Integer.toHexString(md5[i] & 0xf));
-    }
-
-    return sb.toString();
-  }
-
-  protected int writeEntryPointCall(String entry, Writer out) throws IOException {
-    // Emit entry point call.
-    // TODO: Actually validate that this method exists.
-    // Small hack: the V8 arguments object is not an instance of Array. [].concat(arguments)
-    // copies the elements of the arguments and returns a proper array.
-    // However in Rhino this operation simply creates an array with 'arguments' as the first (and
-    // only) element. By calling "arguments.slice()" on it, a new array is returned, and the
-    // concatenation works again.
-    // TODO: Use a more robust check to test that the argument is
-    // array.
-    String entryPointCall = "RunEntry(" + entry + ", this.arguments ?" +
-              " (this.arguments.slice ? [].concat(this.arguments.slice())" +
-              " : this.arguments) : []);";
-    out.write(entryPointCall);
-    return entryPointCall.length();
-  }
-
-  protected String getMangledEntryPoint(DartCompilerContext context) {
-    MethodElement entry = context.getApplicationUnit().getElement().getEntryPoint();
-    if (entry == null) {
-      return null;
-    }
-
-    return mangler.mangleEntryPoint(entry, context.getApplicationUnit().getElement());
-  }
-
-  @Override
-  public boolean isOutOfDate(DartSource src, DartCompilerContext context) {
-    return context.isOutOfDate(src, src, EXTENSION_JS);
-  }
-
-  @Override
-  public void compileUnit(DartUnit unit, DartSource src, DartCompilerContext context,
-      CoreTypeProvider typeProvider) throws IOException {
-    // Translate the AST to JS.
-    Map<String, JsProgram> parts = translateToJS(unit, context, typeProvider);
-    String srcName = src.getName();
-
-    for (Map.Entry<String, JsProgram> entry : parts.entrySet()) {
-      // Generate Javascript output.
-      TextOutput out = new DefaultTextOutput(false);
-      JsToStringGenerationVisitor srcGenerator;
-      String name = entry.getKey();
-      boolean failed = true;
-      Writer w;
-
-      JsProgram program = entry.getValue();
-      JsBlock globalBlock = program.getGlobalBlock();
-
-      TraceEvent srcEvent =
-          Tracer.canTrace() ? Tracer.start(DartEventType.JS_SOURCE_GEN, "src", srcName, "name",
-              name) : null;
-      try {
-        srcGenerator = new JsSourceGenerationVisitor(out);
-
-        srcGenerator.accept(globalBlock);
-        w = context.getArtifactWriter(src, name, EXTENSION_JS);
-        try {
-          w.write(out.toString());
-          failed = false;
-        } finally {
-          Closeables.close(w, failed);
-        }
-      } finally {
-        Tracer.end(srcEvent);
-      }
-    }
-  }
-}