Remove backends.

compiler/java/com/google/dart/compiler/backend/js/analysis/TreeShaker.java

Index: compiler/java/com/google/dart/compiler/backend/js/analysis/TreeShaker.java
diff --git a/compiler/java/com/google/dart/compiler/backend/js/analysis/TreeShaker.java b/compiler/java/com/google/dart/compiler/backend/js/analysis/TreeShaker.java
deleted file mode 100644
index 27a975224cb3add388e26d1f2e9f5d7e70429ae7..0000000000000000000000000000000000000000
--- a/compiler/java/com/google/dart/compiler/backend/js/analysis/TreeShaker.java
+++ /dev/null
@@ -1,191 +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.analysis;
-
-import com.google.common.io.CharStreams;
-import com.google.common.io.Closeables;
-import com.google.dart.compiler.DartCompilerContext;
-import com.google.dart.compiler.LibrarySource;
-
-import org.mozilla.javascript.EvaluatorException;
-import org.mozilla.javascript.Parser;
-import org.mozilla.javascript.ast.AstNode;
-import org.mozilla.javascript.ast.AstRoot;
-import org.mozilla.javascript.ast.NodeVisitor;
-
-import java.io.IOException;
-import java.io.Reader;
-import java.io.Writer;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.LinkedHashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-
-/**
- * A JavaScript tree shaker that is specialized for the output produced by
- * dartc.
- */
-public class TreeShaker {
-  private static class VisitorIOException extends RuntimeException {
-    public VisitorIOException(IOException e) {
-      super(e);
-    }
-
-    @Override
-    public IOException getCause() {
-      return (IOException) super.getCause();
-    }
-  }
-
-  private static final class OutputFileWriter implements NodeVisitor {
-    private final Set<AstNode> nodesToEmit;
-    private final Writer outputFile;
-    private final Reader inputFile;
-    private long lastReadPosition = 0;
-    private long outputSize = 0;
-
-    private OutputFileWriter(Set<AstNode> nodesToEmit, Writer outputFile, Reader inputFile) {
-      this.nodesToEmit = nodesToEmit;
-      this.outputFile = outputFile;
-      this.inputFile = inputFile;
-    }
-
-    @Override
-    public boolean visit(AstNode node) {
-      if (node.getAstRoot() == node) {
-        return true;
-      }
-
-      try {
-        if (nodesToEmit.contains(node)) {
-          int nodePosition = node.getAbsolutePosition();
-          inputFile.skip(nodePosition - lastReadPosition);
-
-          char[] buffer = new char[node.getLength()];
-          int charsRead = inputFile.read(buffer);
-          assert (charsRead == buffer.length);
-          outputFile.write(buffer);
-          outputFile.write("\n");
-          outputSize += charsRead + 1;
-          lastReadPosition = nodePosition + node.getLength();
-        }
-      } catch (IOException e) {
-        throw new VisitorIOException(e);
-      }
-
-      return false;
-    }
-
-    public long getOutputSize() {
-      return outputSize;
-    }
-  }
-
-  private static final boolean DEBUG = false;
-
-  /**
-   * Returns the set of {@link AstNode}s that should be emitted into the final
-   * JS code.
-   */
-  private static Set<AstNode> computeNodesToEmit(AstRoot root) {
-    List<AstNode> globals = new ArrayList<AstNode>();
-    Map<String, List<JavascriptElement>> namesToElements =
-        new HashMap<String, List<JavascriptElement>>();
-    TopLevelElementIndexer declVisitor = new TopLevelElementIndexer(namesToElements, globals);
-    root.visit(declVisitor);
-
-    if (DEBUG) {
-      TopLevelElementIndexer.printNamesToElements(namesToElements);
-      TopLevelElementIndexer.printGlobals(globals);
-    }
-
-    List<AstNode> worklist = new ArrayList<AstNode>();
-    for (AstNode global : globals) {
-      worklist.add(global);
-    }
-
-    worklist.addAll(declVisitor.getEntryPoints());
-    DependencyComputer dependencyComputer = new DependencyComputer(namesToElements);
-    final Set<AstNode> nodesProcessed = new LinkedHashSet<AstNode>();
-    while (!worklist.isEmpty()) {
-      AstNode node = worklist.remove(worklist.size() - 1);
-      if (!nodesProcessed.add(node)) {
-        continue;
-      }
-
-      if (DEBUG) {
-        try {
-          System.out.println(node.toSource());
-          System.out.println("Dependencies:");
-        } catch (Exception e) {
-          // Ignore exceptions thrown by rhino's toSource method...
-        }
-      }
-
-      List<JavascriptElement> dependencies = dependencyComputer.computeDependencies(node);
-      for (JavascriptElement dependency : dependencies) {
-        if (dependency.isNative() || nodesProcessed.contains(dependency.getNode())) {
-          // Skip natives since they don't have a node in the AST
-          continue;
-        }
-
-        if (DEBUG) {
-          System.out.println("\t" + dependency.getQualifiedName());
-        }
-
-        worklist.add(dependency.getNode());
-      }
-    }
-    return nodesProcessed;
-  }
-
-  /**
-   * Reduce the input JS file by following the conservative "call graph" and
-   * pruning dead code.
-   */
-  public static long reduce(LibrarySource app, DartCompilerContext context,
-      String completeArtifactName, Writer outputFile) throws IOException {
-    Reader inputFile = context.getArtifactReader(app, "", completeArtifactName);
-    // Mark beyond the expected length so we can reset back to zero
-    AstRoot root = null;
-    boolean failed = true;
-    try {
-      Parser parser = new Parser();
-      root = parser.parse(inputFile, "", 1);
-      failed = false;
-    } catch (EvaluatorException e) {
-      /*
-       * This can happen if we generate bad JS code. For example, the negative
-       * tests may cause invalid control flow constructs to be generated. In
-       * this case we will swallow the exception and simply copy the input file
-       * to the output file.
-       */
-      Closeables.close(inputFile, failed);
-      inputFile = context.getArtifactReader(app, "", completeArtifactName);
-      return CharStreams.copy(inputFile, outputFile);
-    } finally {
-      Closeables.close(inputFile, failed);
-    }
-
-    final Set<AstNode> nodesProcessed = computeNodesToEmit(root);
-
-    // Need to get a new reader since we don't cache the stream
-    failed = true;
-    inputFile = context.getArtifactReader(app, "", completeArtifactName);
-    OutputFileWriter outputFileWriter =
-        new OutputFileWriter(nodesProcessed, outputFile, inputFile);
-    try {
-      root.visit(outputFileWriter);
-      failed = false;
-      return outputFileWriter.getOutputSize();
-    } catch (VisitorIOException e) {
-      throw e.getCause();
-    } finally {
-      Closeables.close(inputFile, failed);
-    }
-  }
-}