| /* |
| * Copyright 2009 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.BadPropertyValueException; |
| import com.google.gwt.core.ext.ConfigurationProperty; |
| import com.google.gwt.core.ext.PropertyOracle; |
| import com.google.gwt.core.ext.SelectionProperty; |
| import com.google.gwt.core.ext.TreeLogger; |
| import com.google.gwt.resources.css.ast.Context; |
| import com.google.gwt.resources.css.ast.CssCompilerException; |
| import com.google.gwt.resources.css.ast.CssIf; |
| import com.google.gwt.resources.css.ast.CssModVisitor; |
| import com.google.gwt.resources.css.ast.CssNode; |
| |
| import java.util.Arrays; |
| |
| /** |
| * Statically evaluates {@literal @if} rules. |
| */ |
| public class IfEvaluator extends CssModVisitor { |
| private final TreeLogger logger; |
| private final PropertyOracle oracle; |
| |
| public IfEvaluator(TreeLogger logger, PropertyOracle oracle) { |
| this.logger = logger.branch(TreeLogger.DEBUG, |
| "Replacing property-based @if blocks"); |
| this.oracle = oracle; |
| } |
| |
| @Override |
| public void endVisit(CssIf x, Context ctx) { |
| if (x.getExpression() != null) { |
| // This gets taken care of by the runtime substitution visitor |
| } else { |
| try { |
| String propertyName = x.getPropertyName(); |
| String propValue = null; |
| try { |
| SelectionProperty selProp = oracle.getSelectionProperty(logger, |
| propertyName); |
| propValue = selProp.getCurrentValue(); |
| } catch (BadPropertyValueException e) { |
| ConfigurationProperty confProp = oracle.getConfigurationProperty(propertyName); |
| propValue = confProp.getValues().get(0); |
| } |
| |
| /* |
| * If the deferred binding property's value is in the list of values in |
| * the @if rule, move the rules into the @if's context. |
| */ |
| if (Arrays.asList(x.getPropertyValues()).contains(propValue) |
| ^ x.isNegated()) { |
| for (CssNode n : x.getNodes()) { |
| ctx.insertBefore(n); |
| } |
| } else { |
| // Otherwise, move the else block into the if statement's position |
| for (CssNode n : x.getElseNodes()) { |
| ctx.insertBefore(n); |
| } |
| } |
| |
| // Always delete @if rules that we can statically evaluate |
| ctx.removeMe(); |
| } catch (BadPropertyValueException e) { |
| logger.log(TreeLogger.ERROR, "Unable to evaluate @if block", e); |
| throw new CssCompilerException("Unable to parse CSS", e); |
| } |
| } |
| } |
| } |