    001// Copyright 2009-2013 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007//     http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5.internal.services;
    016
    017import org.apache.tapestry5.commons.Location;
    018import org.apache.tapestry5.commons.Resource;
    019import org.apache.tapestry5.commons.util.CollectionFactory;
    020import org.apache.tapestry5.commons.util.ExceptionUtils;
    021import org.apache.tapestry5.ioc.internal.util.InternalUtils;
    022import org.apache.tapestry5.ioc.internal.util.LocationImpl;
    023import org.xml.sax.*;
    024import org.xml.sax.ext.Attributes2;
    025import org.xml.sax.ext.LexicalHandler;
    026import org.xml.sax.helpers.XMLReaderFactory;
    027
    028import javax.xml.namespace.QName;
    029import java.io.*;
    030import java.net.URL;
    031import java.util.Collections;
    032import java.util.List;
    033import java.util.Map;
    034
    035/**
    036 * Parses a document as a stream of XML tokens. It includes a special hack (as of Tapestry 5.3) to support the HTML5 doctype ({@code <!DOCTYPE html>})
    037 * as if it were the XHTML transitional doctype
    038 * ({@code <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">}).
    039 */
    040public class XMLTokenStream
    041{
    042
    043    public static final String TRANSITIONAL_DOCTYPE = "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">";
    044
    045    private static final DTDData HTML5_DTD_DATA = new DTDData("html", null, null);
    046
    047    private final class SaxHandler implements LexicalHandler, EntityResolver, ContentHandler
    048    {
    049        private Locator locator;
    050
    051        private int currentLine = -1;
    052
    053        private Location cachedLocation;
    054
    055        private Location textLocation;
    056
    057        private final StringBuilder builder = new StringBuilder();
    058
    059        private boolean inCDATA, insideDTD;
    060
    061        private List<NamespaceMapping> namespaceMappings = CollectionFactory.newList();
    062
    063        private Location getLocation()
    064        {
    065            if (locator == null)
    066            {
    067                if (cachedLocation == null)
    068                {
    069                    cachedLocation = new LocationImpl(resource);
    070                }
    071            } else {
    072                int line = locator.getLineNumber();
    073
    074                if (currentLine != line)
    075                    cachedLocation = null;
    076
    077                if (cachedLocation == null)
    078                {
    079                    // lineOffset accounts for the extra line when a doctype is injected. The line number reported
    080                    // from the XML parser inlcudes the phantom doctype line, the lineOffset is used to subtract one
    081                    // to get the real line number.
    082                    cachedLocation = new LocationImpl(resource, line + lineOffset);
    083                }
    084            }
    085
    086            return cachedLocation;
    087        }
    088
    089        private XMLToken add(XMLTokenType type)
    090        {
    091            XMLToken token = new XMLToken(type, getLocation());
    092
    093            tokens.add(token);
    094
    095            return token;
    096        }
    097
    098        public InputSource resolveEntity(String publicId, String systemId) throws SAXException,
    099                IOException
    100        {
    101            URL url = publicIdToURL.get(publicId);
    102
    103            try
    104            {
    105                if (url != null)
    106                    return new InputSource(url.openStream());
    107            } catch (IOException ex)
    108            {
    109                throw new SAXException(String.format("Unable to open stream for resource %s: %s",
    110                        url, ExceptionUtils.toMessage(ex)), ex);
    111            }
    112
    113            return null;
    114        }
    115
    116        public void comment(char[] ch, int start, int length) throws SAXException
    117        {
    118            if (insideDTD)
    119                return;
    120
    121            // TODO: Coalesce?
    122            add(XMLTokenType.COMMENT).text = new String(ch, start, length);
    123        }
    124
    125        public void startCDATA() throws SAXException
    126        {
    127            // TODO: Flush characters?
    128
    129            inCDATA = true;
    130        }
    131
    132        public void endCDATA() throws SAXException
    133        {
    134            if (builder.length() != 0)
    135            {
    136                add(XMLTokenType.CDATA).text = builder.toString();
    137            }
    138
    139            builder.setLength(0);
    140            inCDATA = false;
    141        }
    142
    143        public void characters(char[] ch, int start, int length) throws SAXException
    144        {
    145            if (inCDATA)
    146            {
    147                builder.append(ch, start, length);
    148                return;
    149            }
    150
    151            XMLToken token = new XMLToken(XMLTokenType.CHARACTERS, textLocation);
    152            token.text = new String(ch, start, length);
    153
    154            tokens.add(token);
    155        }
    156
    157        public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException
    158        {
    159            characters(ch, start, length);
    160        }
    161
    162        public void startDTD(final String name, final String publicId, final String systemId)
    163                throws SAXException
    164        {
    165            insideDTD = true;
    166
    167            if (!ignoreDTD)
    168            {
    169                DTDData data = html5DTD ? HTML5_DTD_DATA : new DTDData(name, publicId, systemId);
    170
    171                add(XMLTokenType.DTD).dtdData = data;
    172            }
    173        }
    174
    175        public void endDocument() throws SAXException
    176        {
    177            add(XMLTokenType.END_DOCUMENT);
    178        }
    179
    180        public void endElement(String uri, String localName, String qName) throws SAXException
    181        {
    182            add(XMLTokenType.END_ELEMENT);
    183        }
    184
    185        public void setDocumentLocator(Locator locator)
    186        {
    187            this.locator = locator;
    188        }
    189
    190        /**
    191         * Checks for the extra namespace injected when the transitional doctype is injected (which
    192         * occurs when the template contains no doctype).
    193         */
    194        private boolean ignoreURI(String uri)
    195        {
    196            return ignoreDTD && uri.equals("http://www.w3.org/1999/xhtml");
    197        }
    198
    199        public void startElement(String uri, String localName, String qName, Attributes attributes)
    200                throws SAXException
    201        {
    202            XMLToken token = add(XMLTokenType.START_ELEMENT);
    203
    204            token.uri = ignoreURI(uri) ? "" : uri;
    205            token.localName = localName;
    206            token.qName = qName;
    207
    208            // The XML parser tends to reuse the same Attributes object, so
    209            // capture the data out of it.
    210
    211            Attributes2 a2 = (attributes instanceof Attributes2) ? (Attributes2) attributes : null;
    212
    213            if (attributes.getLength() == 0)
    214            {
    215                token.attributes = Collections.emptyList();
    216            } else
    217            {
    218                token.attributes = CollectionFactory.newList();
    219
    220                for (int i = 0; i < attributes.getLength(); i++)
    221                {
    222                    // Filter out attributes that are not present in the XML input stream, but were
    223                    // instead provided by DTD defaulting.
    224
    225                    if (a2 != null && !a2.isSpecified(i))
    226                    {
    227                        continue;
    228                    }
    229
    230                    String prefixedName = attributes.getQName(i);
    231
    232                    int lastColon = prefixedName.lastIndexOf(':');
    233
    234                    String prefix = lastColon > 0 ? prefixedName.substring(0, lastColon) : "";
    235
    236                    QName qname = new QName(attributes.getURI(i), attributes.getLocalName(i),
    237                            prefix);
    238
    239                    token.attributes.add(new AttributeInfo(qname, attributes.getValue(i)));
    240                }
    241            }
    242
    243            token.namespaceMappings = CollectionFactory.newList(namespaceMappings);
    244
    245            namespaceMappings.clear();
    246
    247            // Any text collected starts here as well:
    248
    249            textLocation = getLocation();
    250        }
    251
    252        public void startPrefixMapping(String prefix, String uri) throws SAXException
    253        {
    254            if (ignoreDTD && prefix.equals("") && uri.equals("http://www.w3.org/1999/xhtml"))
    255            {
    256                return;
    257            }
    258
    259            namespaceMappings.add(new NamespaceMapping(prefix, uri));
    260        }
    261
    262        public void endDTD() throws SAXException
    263        {
    264            insideDTD = false;
    265        }
    266
    267        public void endEntity(String name) throws SAXException
    268        {
    269        }
    270
    271        public void startEntity(String name) throws SAXException
    272        {
    273        }
    274
    275        public void endPrefixMapping(String prefix) throws SAXException
    276        {
    277        }
    278
    279        public void processingInstruction(String target, String data) throws SAXException
    280        {
    281        }
    282
    283        public void skippedEntity(String name) throws SAXException
    284        {
    285        }
    286
    287        public void startDocument() throws SAXException
    288        {
    289        }
    290    }
    291
    292    private int cursor = -1;
    293
    294    private final List<XMLToken> tokens = CollectionFactory.newList();
    295
    296    private final Resource resource;
    297
    298    private final Map<String, URL> publicIdToURL;
    299
    300    private Location exceptionLocation;
    301
    302    private boolean html5DTD, ignoreDTD;
    303
    304    private int lineOffset;
    305
    306    public XMLTokenStream(Resource resource, Map<String, URL> publicIdToURL)
    307    {
    308        this.resource = resource;
    309        this.publicIdToURL = publicIdToURL;
    310    }
    311
    312    public void parse() throws SAXException, IOException
    313    {
    314        SaxHandler handler = new SaxHandler();
    315
    316        XMLReader reader = XMLReaderFactory.createXMLReader();
    317
    318        reader.setContentHandler(handler);
    319        reader.setEntityResolver(handler);
    320        reader.setProperty("http://xml.org/sax/properties/lexical-handler", handler);
    321
    322        InputStream stream = null;
    323
    324        try
    325        {
    326            stream = openStream();
    327            reader.parse(new InputSource(stream));
    328        } catch (IOException ex)
    329        {
    330            this.exceptionLocation = handler.getLocation();
    331
    332            throw ex;
    333        } catch (SAXException ex)
    334        {
    335            this.exceptionLocation = handler.getLocation();
    336
    337            throw ex;
    338        } catch (RuntimeException ex)
    339        {
    340            this.exceptionLocation = handler.getLocation();
    341
    342            throw ex;
    343        } finally
    344        {
    345            InternalUtils.close(stream);
    346        }
    347    }
    348
    349    enum State
    350    {
    351        MAYBE_XML, MAYBE_DOCTYPE, JUST_COPY
    352    }
    353
    354    private InputStream openStream() throws IOException
    355    {
    356        InputStream rawStream = resource.openStream();
    357
    358        String transformationEncoding = "UTF8";
    359
    360        InputStreamReader rawReader = new InputStreamReader(rawStream, transformationEncoding);
    361        LineNumberReader reader = new LineNumberReader(rawReader);
    362
    363        ByteArrayOutputStream bos = new ByteArrayOutputStream(5000);
    364        PrintWriter writer = new PrintWriter(new OutputStreamWriter(bos, transformationEncoding));
    365
    366        State state = State.MAYBE_XML;
    367
    368        try
    369        {
    370            while (true)
    371            {
    372                String line = reader.readLine();
    373
    374                if (line == null)
    375                {
    376                    break;
    377                }
    378
    379                switch (state)
    380                {
    381
    382                    case MAYBE_XML:
    383
    384                        if (line.toLowerCase().startsWith("<?xml"))
    385                        {
    386                            writer.println(line);
    387                            state = State.MAYBE_DOCTYPE;
    388                            continue;
    389                        }
    390
    391                    case MAYBE_DOCTYPE:
    392
    393                        if (line.trim().length() == 0)
    394                        {
    395                            writer.println(line);
    396                            continue;
    397                        }
    398
    399                        String lineLower = line.toLowerCase();
    400
    401                        if (lineLower.equals("<!doctype html>"))
    402                        {
    403                            html5DTD = true;
    404                            writer.println(TRANSITIONAL_DOCTYPE);
    405                            state = State.JUST_COPY;
    406                            continue;
    407                        }
    408
    409
    410                        if (lineLower.startsWith("<!doctype"))
    411                        {
    412                            writer.println(line);
    413                            state = State.JUST_COPY;
    414                            continue;
    415                        }
    416
    417                        // No doctype, let's provide one.
    418
    419                        ignoreDTD = true;
    420                        lineOffset = -1;
    421                        writer.println(TRANSITIONAL_DOCTYPE);
    422
    423                        state = State.JUST_COPY;
    424
    425                        // And drop down to writing out the actual line, and all following lines.
    426
    427                    case JUST_COPY:
    428                        writer.println(line);
    429                }
    430            }
    431        } finally
    432        {
    433            writer.close();
    434            reader.close();
    435        }
    436
    437        return new ByteArrayInputStream(bos.toByteArray());
    438    }
    439
    440    private XMLToken token()
    441    {
    442        return cursor == -1 ? null : tokens.get(cursor);
    443    }
    444
    445    /**
    446     * Returns the type of the next token.
    447     */
    448    public XMLTokenType next()
    449    {
    450        cursor++;
    451
    452        // TODO: Check for overflow?
    453
    454        return getEventType();
    455    }
    456
    457    public int getAttributeCount()
    458    {
    459        return token().attributes.size();
    460    }
    461
    462    public QName getAttributeName(int i)
    463    {
    464        return token().attributes.get(i).attributeName;
    465    }
    466
    467    public DTDData getDTDInfo()
    468    {
    469        return token().dtdData;
    470    }
    471
    472    public XMLTokenType getEventType()
    473    {
    474        return token().type;
    475    }
    476
    477    public String getLocalName()
    478    {
    479        return token().localName;
    480    }
    481
    482    public Location getLocation()
    483    {
    484        if (exceptionLocation != null)
    485            return exceptionLocation;
    486
    487        return token().getLocation();
    488    }
    489
    490    public int getNamespaceCount()
    491    {
    492        return token().namespaceMappings.size();
    493    }
    494
    495    public String getNamespacePrefix(int i)
    496    {
    497        return token().namespaceMappings.get(i).prefix;
    498    }
    499
    500    public String getNamespaceURI()
    501    {
    502        return token().uri;
    503    }
    504
    505    public String getNamespaceURI(int i)
    506    {
    507        return token().namespaceMappings.get(i).uri;
    508    }
    509
    510    public String getText()
    511    {
    512        return token().text;
    513    }
    514
    515    public boolean hasNext()
    516    {
    517        return cursor < tokens.size() - 1;
    518    }
    519
    520    public String getAttributeValue(int i)
    521    {
    522        return token().attributes.get(i).value;
    523    }
    524
    525}