| /* |
| * Copyright 2011 Google Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may not |
| * use this file except in compliance with the License. You may obtain a copy of |
| * the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| * License for the specific language governing permissions and limitations under |
| * the License. |
| */ |
| package com.google.gwt.resources.css; |
| |
| import com.google.gwt.core.ext.TreeLogger; |
| import com.google.gwt.resources.css.ast.CssNode; |
| import com.google.gwt.resources.css.ast.CssStylesheet; |
| import com.google.gwt.resources.css.ast.CssVisitor; |
| |
| import java.util.List; |
| |
| /** |
| * Check a stylesheet to ensure that all of its components are |
| * statically-evaluable. |
| */ |
| public class CheckStaticCssVisitor extends CssVisitor { |
| |
| /** |
| * A fast-fail check to determine if a stylesheet is statically-evaluable. |
| */ |
| public static boolean isStatic(CssStylesheet sheet) { |
| return new CheckStaticCssVisitor(TreeLogger.NULL, true).execImpl(sheet); |
| } |
| |
| /** |
| * Returns <code>true</code> if the stylsheet is statically-evaluable. Nodes |
| * that are not statically-evaluable will be reported to the associated |
| * logger. |
| */ |
| public static boolean report(TreeLogger logger, CssStylesheet sheet) { |
| return new CheckStaticCssVisitor(logger, false).execImpl(sheet); |
| } |
| |
| private boolean error; |
| private final boolean fastFail; |
| private final TreeLogger logger; |
| |
| private CheckStaticCssVisitor(TreeLogger logger, boolean fastFail) { |
| this.logger = logger.branch(TreeLogger.DEBUG, |
| "Checking external stylesheet for dynamic content"); |
| this.fastFail = fastFail; |
| } |
| |
| @Override |
| protected void doAccept(List<? extends CssNode> list) { |
| for (CssNode node : list) { |
| if (error && fastFail) { |
| return; |
| } |
| doAccept(node); |
| } |
| } |
| |
| @Override |
| protected <T extends CssNode> T doAccept(T node) { |
| if (!node.isStatic()) { |
| error(node); |
| } |
| |
| if (error && fastFail) { |
| // Just stop |
| return node; |
| } else { |
| return super.doAccept(node); |
| } |
| } |
| |
| @Override |
| protected void doAcceptWithInsertRemove(List<? extends CssNode> list) { |
| doAccept(list); |
| } |
| |
| void error(CssNode node) { |
| logger.log(TreeLogger.ERROR, "The CSS node " + node.toString() |
| + " cannot be statically evaluated"); |
| error = true; |
| } |
| |
| private boolean execImpl(CssStylesheet sheet) { |
| accept(sheet); |
| return !error; |
| } |
| } |