/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.shindig.gadgets.parse.caja;
import org.apache.shindig.common.cache.Cache;
import org.apache.shindig.common.cache.CacheProvider;
import org.apache.shindig.common.util.HashUtil;
import org.apache.shindig.gadgets.GadgetException;
import com.google.caja.lexer.CharProducer;
import com.google.caja.lexer.CssLexer;
import com.google.caja.lexer.CssTokenType;
import com.google.caja.lexer.InputSource;
import com.google.caja.lexer.ParseException;
import com.google.caja.lexer.Token;
import com.google.common.collect.Lists;
import com.google.inject.Inject;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.net.URI;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* A parser that records the stream of CSS lexial tokens from the Caja lexer and creates a
* pseudo-DOM from that stream.
*
* TODO: Remove once Caja CSS DOM parser issues are resolved.
*/
public class CajaCssLexerParser {
private static final Pattern urlMatcher =
Pattern.compile("(url\\s*\\(\\s*['\"]?)([^\\)'\"]*)(['\"]?\\s*\\))",
Pattern.CASE_INSENSITIVE);
private static final URI DUMMY_SOURCE = URI.create("http://www.example.org");
public static final String CACHE_NAME = "parsedCss";
private Cache<String, List<Object>> parsedCssCache;
@Inject
public void setCacheProvider(CacheProvider cacheProvider) {
parsedCssCache = cacheProvider.createCache(CACHE_NAME);
}
public List<Object> parse(String content) throws GadgetException {
List<Object> parsedCss = null;
boolean shouldCache = shouldCache();
String key = null;
if (shouldCache) {
// TODO - Consider using the source if its under a certain size
key = HashUtil.rawChecksum(content.getBytes());
parsedCss = parsedCssCache.getElement(key);
}
if (parsedCss == null) {
parsedCss = parseImpl(content);
if (shouldCache) {
parsedCssCache.addElement(key, parsedCss);
}
}
if (shouldCache) {
List<Object> cloned = Lists.newArrayListWithExpectedSize(parsedCss.size());
for (Object o : parsedCss) {
if (o instanceof ImportDecl) {
cloned.add(new ImportDecl(((ImportDecl) o).getUri()));
} else if (o instanceof UriDecl) {
cloned.add(new UriDecl(((UriDecl) o).getUri()));
} else {
cloned.add(o);
}
}
return cloned;
}
return parsedCss;
}
List<Object> parseImpl(String content) throws GadgetException {
List<Object> parsedCss = Lists.newArrayList();
CharProducer producer = CharProducer.Factory.create(new StringReader(content),
new InputSource(DUMMY_SOURCE));
CssLexer lexer = new CssLexer(producer);
try {
StringBuilder builder = new StringBuilder();
boolean inImport = false;
while (lexer.hasNext()) {
Token<CssTokenType> token = lexer.next();
if (token.type == CssTokenType.SYMBOL && token.text.equalsIgnoreCase("@import")) {
parsedCss.add(builder.toString());
builder.setLength(0);
inImport = true;
} else if (inImport) {
if (token.type == CssTokenType.URI) {
parsedCss.add(builder.toString());
builder.setLength(0);
Matcher matcher = urlMatcher.matcher(token.text);
if (matcher.find()) {
parsedCss.add(new ImportDecl(matcher.group(2).trim()));
}
} else if (token.type != CssTokenType.SPACE && token.type != CssTokenType.PUNCTUATION) {
inImport = false;
builder.append(token.text);
} else {
//builder.append(token.text);
}
} else if (token.type == CssTokenType.URI) {
Matcher matcher = urlMatcher.matcher(token.text);
if (!matcher.find()) {
builder.append(token.text);
} else {
parsedCss.add(builder.toString());
builder.setLength(0);
parsedCss.add(new UriDecl(matcher.group(2).trim()));
}
} else {
builder.append(token.text);
}
}
parsedCss.add(builder.toString());
} catch (ParseException pe) {
throw new GadgetException(GadgetException.Code.CSS_PARSE_ERROR, pe);
}
return parsedCss;
}
/** Serialize a stylesheet to a String */
public String serialize(List<Object> styleSheet) {
StringWriter writer = new StringWriter();
serialize(styleSheet, writer);
return writer.toString();
}
/** Serialize a stylesheet to a Writer. */
public void serialize(List<Object> styleSheet, Appendable writer) {
try {
for (Object o : styleSheet) {
writer.append(o.toString());
}
} catch (IOException ioe) {
throw new RuntimeException(ioe);
}
}
private boolean shouldCache() {
return parsedCssCache != null && parsedCssCache.getCapacity() != 0;
}
public static class ImportDecl {
private String uri;
public ImportDecl(String uri) {
this.uri = uri;
}
public String getUri() {
return uri;
}
public void setUri(String uri) {
this.uri = uri;
}
public String toString() {
return "@import url('" + uri + "');\n";
}
}
public static class UriDecl {
private String uri;
public UriDecl(String uri) {
this.uri = uri;
}
public String getUri() {
return uri;
}
public void setUri(String uri) {
this.uri = uri;
}
public String toString() {
return "url('" + uri + "')";
}
}
}