/*
* Copyright 2014 Julien Dramaix.
*
* 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.gss;
import com.google.common.collect.Lists;
import com.google.common.css.compiler.ast.CssAtRuleNode.Type;
import com.google.common.css.compiler.ast.CssBooleanExpressionNode;
import com.google.common.css.compiler.ast.CssCompilerPass;
import com.google.common.css.compiler.ast.CssConditionalBlockNode;
import com.google.common.css.compiler.ast.CssConditionalRuleNode;
import com.google.common.css.compiler.ast.CssValueNode;
import com.google.common.css.compiler.ast.DefaultTreeVisitor;
import com.google.common.css.compiler.ast.MutatingVisitController;
import com.google.gwt.resources.gss.ast.CssJavaExpressionNode;
import com.google.gwt.resources.gss.ast.CssRuntimeConditionalRuleNode;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class CreateRuntimeConditionalNodes extends DefaultTreeVisitor implements CssCompilerPass {
private static final Pattern EVAL_FUNCTION = Pattern.compile("^eval\\([\"']([^\"']*)[\"']\\)$");
private final MutatingVisitController visitController;
public CreateRuntimeConditionalNodes(MutatingVisitController visitController) {
this.visitController = visitController;
}
@Override
public boolean enterConditionalBlock(CssConditionalBlockNode block) {
// we have to visit all the CssConditionalRuleNode when we visit the CssConditionalBlockNode
// parent node because we are going to replace CssConditionalRuleNode by another node and
// unfortunately the visitController doesn't support to replace a CssConditionalRuleNode and
// we have to do it manually. That implies that the new nodes won't be visited by the
// visitor if we do that during the visit of the CssConditionalRuleNodes.
// make a copy in order to avoid ConcurrentModificationException
List<CssConditionalRuleNode> children = Lists.newArrayList(block.getChildren());
for (CssConditionalRuleNode ruleNode : children) {
manuallyVisitConditionalRule(ruleNode, block);
}
return true;
}
private void manuallyVisitConditionalRule(CssConditionalRuleNode node,
CssConditionalBlockNode parent) {
if (node.getType() != Type.ELSE) {
CssBooleanExpressionNode nodeCondition = node.getCondition();
String condition = extractRuntimeCondition(nodeCondition);
if (condition != null) {
CssJavaExpressionNode newNode = new CssJavaExpressionNode(condition,
nodeCondition.getSourceCodeLocation());
CssRuntimeConditionalRuleNode newRuleNode = new CssRuntimeConditionalRuleNode(node,
newNode);
// unfortunately visitController.replaceCurrentBlockChildWith doesn't work with
// CssConditionnalRuleNode
int index = parent.getChildren().indexOf(node);
parent.replaceChildAt(index, Lists.newArrayList(newRuleNode));
}
}
}
private String extractRuntimeCondition(CssValueNode node) {
Matcher m = EVAL_FUNCTION.matcher(node.getValue());
return m.matches() ? m.group(1) : null;
}
@Override
public void runPass() {
visitController.startVisit(this);
}
}