Java Node.removeChild方法代码示例

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/**
 * Merge a block with its parent block.
 * @return Whether the block was removed.
 */
static boolean tryMergeBlock(Node block) {
  Preconditions.checkState(block.getType() == Token.BLOCK);
  Node parent = block.getParent();
  // Try to remove the block if its parent is a block/script or if its
  // parent is label and it has exactly one child.
  if (NodeUtil.isStatementBlock(parent)) {
    Node previous = block;
    while (block.hasChildren()) {
      Node child = block.removeFirstChild();
      parent.addChildAfter(child, previous);
      previous = child;
    }
    parent.removeChild(block);
    return true;
  } else if (parent.getType() == Token.LABEL && block.hasOneChild()) {
    parent.replaceChild(block, block.removeFirstChild());
    return true;
  } else {
    return false;
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/**
 * Move all the child nodes following start in srcParent to the end of
 * destParent's child list.
 * @param start The start point in the srcParent child list.
 * @param srcParent The parent node of start.
 * @param destParent The destination node.
 */
static private void moveAllFollowing(
    Node start, Node srcParent, Node destParent) {
  for (Node n = start.getNext(); n != null; n = start.getNext()) {
    boolean isFunctionDeclaration =
        NodeUtil.isFunctionDeclaration(n);

    srcParent.removeChild(n);

    if (isFunctionDeclaration) {
      destParent.addChildToFront(n);
    } else {
      destParent.addChildToBack(n);
    }
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/**
 * Removes declarations of any variables whose names are strip names or
 * whose whose rvalues are static method calls on strip types. Builds a set
 * of removed variables so that all references to them can be removed.
 *
 * @param t The traversal
 * @param n A VAR node
 * @param parent {@code n}'s parent
 */
void removeVarDeclarationsByNameOrRvalue(NodeTraversal t, Node n,
    Node parent) {
  for (Node nameNode = n.getFirstChild(); nameNode != null;
      nameNode = nameNode.getNext()) {
    String name = nameNode.getString();
    if (isStripName(name) ||
        isCallWhoseReturnValueShouldBeStripped(nameNode.getFirstChild())) {
      // Remove the NAME.
      Scope scope = t.getScope();
      varsToRemove.add(scope.getVar(name));
      n.removeChild(nameNode);
      compiler.reportCodeChange();
    }
  }
  if (!n.hasChildren()) {
    // Must also remove the VAR.
    replaceWithEmpty(n, parent);
    compiler.reportCodeChange();
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/**
 * Eliminates any object literal keys in an object literal declaration that
 * have strip names.
 *
 * @param t The traversal
 * @param n An OBJLIT node
 */
void eliminateKeysWithStripNamesFromObjLit(NodeTraversal t, Node n) {
  // OBJLIT
  //   key1
  //   value1
  //   ...
  Node key = n.getFirstChild();
  while (key != null) {
    if (key.getType() == Token.STRING &&
        isStripName(key.getString())) {
      Node value = key.getNext();
      Node next = value.getNext();
      n.removeChild(key);
      n.removeChild(value);
      key = next;
      compiler.reportCodeChange();
    } else {
      key = key.getNext().getNext();
    }
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/**
 * Removes unreferenced arguments from a function declaration.
 *
 * @param function The FUNCTION node
 * @param fnScope The scope inside the function
 */
private void removeUnreferencedFunctionArgs(Node function, Scope fnScope) {
  // Strip unreferenced args off the end of the function declaration.
  Node argList = function.getFirstChild().getNext();
  Node lastArg;
  while ((lastArg = argList.getLastChild()) != null) {
    Var var = fnScope.getVar(lastArg.getString());
    if (!referenced.contains(var)) {
      argList.removeChild(lastArg);
      fnScope.undeclare(var);
      numRemoved_++;
    } else {
      break;
    }
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/** {@inheritDoc} */
public void visit(NodeTraversal t, Node n, Node parent) {
  switch (n.getType()) {
    case Token.GETELEM:
      Node left = n.getFirstChild();
      Node right = left.getNext();
      if (right.getType() == Token.STRING &&
          NodeUtil.isValidPropertyName(right.getString())) {
        n.removeChild(left);
        n.removeChild(right);
        parent.replaceChild(n, new Node(Token.GETPROP, left, right));
        compiler.reportCodeChange();
      }
      break;
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
private void replaceAccessor(Node getPropNode) {
  /*
   *  BEFORE
      getprop
          NODE...
          string length
      AFTER
      getelem
          NODE...
          name PROP_length
   */
  Node propNameNode = getPropNode.getLastChild();
  String propName = propNameNode.getString();
  if (props.get(propName).aliasAccessor) {
    Node propSrc = getPropNode.getFirstChild();
    getPropNode.removeChild(propSrc);

    Node newNameNode =
      Node.newString(Token.NAME, getArrayNotationNameFor(propName));

    Node elemNode = new Node(Token.GETELEM, propSrc, newNameNode);
    replaceNode(getPropNode.getParent(), getPropNode, elemNode);

    compiler.reportCodeChange();
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/**
 * Updates the first initialization (a.k.a "declaration") of a global name
 * that occurs at a VAR node. See comment for
 * {@link #updateObjLitOrFunctionDeclaration}.
 *
 * @param n An object representing a global name (e.g. "a")
 */
private void updateObjLitOrFunctionDeclarationAtVarNode(Name n) {
  Ref ref = n.declaration;
  String name = ref.node.getString();
  Node rvalue = ref.node.getFirstChild();
  Node varNode = ref.node.getParent();
  Node gramps = varNode.getParent();

  boolean isObjLit = rvalue.getType() == Token.OBJECTLIT;
  int numChanges = 0;

  if (isObjLit) {
    boolean discardKeys = n.aliasingGets == 0;
    numChanges += declareVarsForObjLitValues(
        n, name, rvalue, varNode, gramps.getChildBefore(varNode),
        gramps, discardKeys);
  }

  numChanges += addStubsForUndeclaredProperties(n, name, gramps, varNode);

  if (isObjLit && n.canEliminate()) {
    varNode.removeChild(ref.node);
    if (!varNode.hasChildren()) {
      gramps.removeChild(varNode);
    }
    numChanges++;

    // Clear out the object reference, since we've eliminated it from the
    // parse tree.
    ref.node = null;
  }

  if (numChanges > 0) {
    compiler.reportCodeChange();
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/** Safely remove children while maintaining a valid node structure. */
static void removeChild(Node parent, Node node) {
  // Node parent = node.getParent();
  if (isStatementBlock(parent)
      || isSwitchCase(node)
      || isTryFinallyNode(parent, node)) {
    // A statement in a block can simply be removed.
    parent.removeChild(node);
  } else if (parent.getType() == Token.VAR) {
    if (parent.hasMoreThanOneChild()) {
      parent.removeChild(node);
    } else {
      // Remove the node from the parent, so it can be reused.
      parent.removeChild(node);
      // This would leave an empty VAR, remove the VAR itself.
      removeChild(parent.getParent(), parent);
    }
  } else if (node.getType() == Token.BLOCK) {
    // Simply empty the block.  This maintains source location and
    // "synthetic"-ness.
    node.detachChildren();
  } else if (parent.getType() == Token.LABEL
      && node == parent.getLastChild()) {
    // Remove the node from the parent, so it can be reused.
    parent.removeChild(node);
    // A LABEL without children can not be referred to, remove it.
    removeChild(parent.getParent(), parent);
  } else if (parent.getType() == Token.FOR
      && parent.getChildCount() == 4) {
    // Only Token.FOR can have an Token.EMPTY other control structure
    // need something for the condition. Others need to be replaced
    // or the structure removed.
    parent.replaceChild(node, new Node(Token.EMPTY));
  } else {
    throw new IllegalStateException("Invalid attempt to remove node: " +
        node.toString() + " of "+ parent.toString());
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/**
 * Remove the given VAR declaration.
 */
private void removeDeclaration(Reference declaration) {
  Node varNode = declaration.getParent();
  varNode.removeChild(declaration.getNameNode());

  // Remove var node if empty
  if (!varNode.hasChildren()) {
    Preconditions.checkState(varNode.getType() == Token.VAR);

    Node grandparent = declaration.getGrandparent();
    NodeUtil.removeChild(grandparent, varNode);
  }

  compiler.reportCodeChange();
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
  if (n.getType() != Token.VAR) {
    return;
  }

  // It is only safe to collapse anonymous functions that appear
  // at top-level blocks.  In other cases the difference between
  // variable and function declarations can lead to problems or
  // expose subtle bugs in browser implementation as function
  // definitions are added to scopes before the start of execution.

  Node grandparent = parent.getParent();
  if (!(parent.getType() == Token.SCRIPT ||
        grandparent != null &&
        grandparent.getType() == Token.FUNCTION &&
        parent.getType() == Token.BLOCK)) {
    return;
  }

  // Need to store the next name in case the current name is removed from
  // the linked list.
  Preconditions.checkState(n.hasOneChild());
  Node name = n.getFirstChild();
  Node value = name.getFirstChild();
  if (value != null &&
      value.getType() == Token.FUNCTION &&
      !isRecursiveFunction(value)) {
    Node fnName = value.getFirstChild();
    fnName.setString(name.getString());
    NodeUtil.copyNameAnnotations(name, fnName);
    name.removeChild(value);
    parent.replaceChild(n, value);
    compiler.reportCodeChange();
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
  if (NodeUtil.isVarDeclaration(n)) {
    if (removable.contains(n.getString())) {
      parent.removeChild(n);
      if (!parent.hasChildren()) {
        parent.getParent().removeChild(parent);
      }
    }
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/**
 * Tries to remove variable declaration if the variable has been coalesced
 * with another variable that has already been declared.
 */
private void removeVarDeclaration(Node name) {
  Node var = name.getParent();
  Node parent = var.getParent();

  // Special case when we are in FOR-IN loop.
  if (NodeUtil.isForIn(parent)) {
    var.removeChild(name);
    parent.replaceChild(var, name);
  } else if (var.getChildCount() == 1) {
    // The removal is easy when there is only one variable in the VAR node.
    if (name.hasChildren()) {
      Node value = name.removeFirstChild();
      var.removeChild(name);
      Node assign = new Node(Token.ASSIGN, name, value);

      // We don't need to wrapped it with EXPR node if it is within a FOR.
      if (parent.getType() != Token.FOR) {
        assign = NodeUtil.newExpr(assign);
      }
      parent.replaceChild(var, assign);

    } else {
      // In a FOR( ; ; ) node, we must replace it with an EMPTY or else it
      // becomes a FOR-IN node.
      NodeUtil.removeChild(parent, var);
    }
  } else {
    if (!name.hasChildren()) {
      var.removeChild(name);
    }
    // We are going to leave duplicated declaration otherwise.
  }
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/**
 * Rename or remove labels.
 * @param node  The label node.
 * @param parent The parent of the label node.
 */
private void visitLabel(Node node, Node parent) {
  Node nameNode = node.getFirstChild();
  Preconditions.checkState(nameNode != null);
  String name = nameNode.getString();
  LabelInfo li = getLabelInfo(name);
  // This is a label...
  if (li.referenced) {
    String newName = getNameForId(li.id);
    if (!name.equals(newName)) {
      // ... and it is used, give it the short name.
      nameNode.setString(newName);
      compiler.reportCodeChange();
    }
  } else {
    // ... and it is not referenced, just remove it.
    Node newChild = node.getLastChild();
    node.removeChild(newChild);
    parent.replaceChild(node, newChild);
    if (newChild.getType() == Token.BLOCK) {
      NodeUtil.tryMergeBlock(newChild);
    }
    compiler.reportCodeChange();
  }

  // Remove the label from the current stack of labels.
  namespaceStack.peek().renameMap.remove(name);
}
 

import com.google.javascript.rhino.Node; //导入方法依赖的package包/类
/**
 * Changes a.prop = b to SETPROP_prop(a, b);
 */
private void replaceMutator(Node getPropNode) {
  /*
     BEFORE
     exprstmt 1
         assign 128
             getprop
                 NodeTree A
                 string prop
             NODE TREE B

     AFTER
     exprstmt 1
         call
             name SETPROP_prop
             NodeTree A
             NODE TREE B
  */
  Node propNameNode = getPropNode.getLastChild();
  Node parentNode = getPropNode.getParent();

  Property prop = props.get(propNameNode.getString());
  if (prop.aliasMutator) {
    Node propSrc = getPropNode.getFirstChild();
    Node propDest = parentNode.getLastChild();

    // Remove the orphaned children
    getPropNode.removeChild(propSrc);
    getPropNode.removeChild(propNameNode);
    parentNode.removeChild(propDest);

    // Create the call GETPROP_prop() node, using the old propSrc as the
    // one paremeter to GETPROP_prop() call.
    Node callName = Node.newString(Token.NAME,
      getMutatorFor(propNameNode.getString()));
    Node call = new Node(Token.CALL, callName, propSrc, propDest);

    // And replace the assign statement with the new call
    replaceNode(parentNode.getParent(), parentNode, call);

    compiler.reportCodeChange();
  }
}