/*
* 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.common.css.compiler.passes;
import com.google.common.collect.ImmutableList;
import com.google.common.css.compiler.ast.CssCompilerPass;
import com.google.common.css.compiler.ast.CssConstantReferenceNode;
import com.google.common.css.compiler.ast.CssLiteralNode;
import com.google.common.css.compiler.ast.CssMixinDefinitionNode;
import com.google.common.css.compiler.ast.CssNode;
import com.google.common.css.compiler.ast.CssRootNode;
import com.google.common.css.compiler.ast.CssValueNode;
import com.google.common.css.compiler.ast.DefaultTreeVisitor;
import com.google.common.css.compiler.ast.MutatingVisitController;
/**
* A compiler pass that transforms each upper-cased {@link CssLiteralNode} to
* a {@link CssConstantReferenceNode}.
*
* @author fbenz@google.com (Florian Benz)
*/
public class CreateConstantReferences extends DefaultTreeVisitor
implements CssCompilerPass {
private final MutatingVisitController visitController;
private CssNode globalScope;
private CssNode currentScope;
public CreateConstantReferences(MutatingVisitController visitController) {
this.visitController = visitController;
}
@Override
public void leaveValueNode(CssValueNode node) {
if (!(node instanceof CssLiteralNode)
|| !CssConstantReferenceNode.isDefinitionReference(node.getValue())) {
return;
}
CssConstantReferenceNode ref =
new CssConstantReferenceNode(node.getValue(),
node.getSourceCodeLocation());
visitController.replaceCurrentBlockChildWith(ImmutableList.of(ref), false);
CssNode scope = determineScope(ref);
ref.setScope(scope);
}
@Override
public void leaveArgumentNode(CssValueNode node) {
leaveValueNode(node);
}
@Override
public boolean enterTree(CssRootNode node) {
globalScope = node;
return true;
}
@Override
public boolean enterMixinDefinition(CssMixinDefinitionNode node) {
currentScope = node;
return true;
}
@Override
public void leaveMixinDefinition(CssMixinDefinitionNode node) {
currentScope = globalScope;
}
/**
* Returns the scope of the given reference.
*/
private CssNode determineScope(CssConstantReferenceNode ref) {
if (currentScope instanceof CssMixinDefinitionNode) {
CssMixinDefinitionNode mixinDef = (CssMixinDefinitionNode) currentScope;
// Search for a matching argument.
for (CssValueNode arg : mixinDef.getArguments().getChildren()) {
if (arg.getValue().equals(ref.getValue())) {
return currentScope;
}
}
}
return globalScope;
}
@Override
public void runPass() {
visitController.startVisit(this);
}
}