// 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 org.apache.tapestry5.internal.webresources;
import com.github.sommeri.less4j.Less4jException;
import com.github.sommeri.less4j.LessCompiler;
import com.github.sommeri.less4j.LessSource;
import com.github.sommeri.less4j.core.DefaultLessCompiler;
import org.apache.tapestry5.ContentType;
import org.apache.tapestry5.internal.services.assets.BytestreamCache;
import org.apache.tapestry5.ioc.Resource;
import org.apache.tapestry5.services.assets.ResourceDependencies;
import org.apache.tapestry5.services.assets.ResourceTransformer;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
/**
* Direct wrapper around the LessCompiler, so that Less source files may use {@code @import}, which isn't
* supported by the normal WRO4J processor.
*/
public class LessResourceTransformer implements ResourceTransformer
{
private static final ContentType CSS = new ContentType("text/css");
private final LessCompiler compiler = new DefaultLessCompiler();
@Override
public ContentType getTransformedContentType()
{
return CSS;
}
@Override
public InputStream transform(Resource source, ResourceDependencies dependencies) throws IOException
{
BytestreamCache compiled = invokeLessCompiler(source, dependencies);
return compiled.openStream();
}
private BytestreamCache invokeLessCompiler(Resource source, ResourceDependencies dependencies) throws IOException
{
try
{
LessSource lessSource = new ResourceLessSource(source, dependencies);
LessCompiler.CompilationResult compilationResult = compile(compiler, lessSource);
// Currently, ignoring any warnings.
return new BytestreamCache(compilationResult.getCss().getBytes("utf-8"));
} catch (Less4jException ex)
{
throw new IOException(ex);
} catch (UnsupportedEncodingException ex)
{
throw new IOException(ex);
}
}
/**
* Invoked from {@link #transform(org.apache.tapestry5.ioc.Resource, org.apache.tapestry5.services.assets.ResourceDependencies)}
* to perform the actual work of compiling a {@link org.apache.tapestry5.ioc.Resource} which has been wrapped as a
* {@link com.github.sommeri.less4j.LessSource}.
*/
protected LessCompiler.CompilationResult compile(LessCompiler compiler, LessSource lessSource) throws Less4jException
{
return compiler.compile(lessSource);
}
}