/*
* Copyright (C) 2007 The Android Open Source Project
*
* 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.harmony.xml;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.ext.LexicalHandler;
import java.io.Reader;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URLConnection;
import java.net.URL;
import java.util.logging.Logger;
import java.util.logging.Level;
/**
* Adapts SAX API to the Expat native XML parser. Not intended for reuse
* across documents.
*
* @see org.apache.harmony.xml.ExpatPullParser
* @see org.apache.harmony.xml.ExpatReader
*/
class ExpatParser {
private static final int BUFFER_SIZE = 8096; // in bytes
/** Pointer to XML_Parser instance. */
private int pointer;
private boolean inStartElement = false;
private int attributeCount = -1;
private int attributePointer = 0;
private final Locator locator = new ExpatLocator();
private final ExpatReader xmlReader;
private final String publicId;
private final String systemId;
private final String encoding;
private final ExpatAttributes attributes = new CurrentAttributes();
private static final String OUTSIDE_START_ELEMENT
= "Attributes can only be used within the scope of startElement().";
/** We default to UTF-8 when the user doesn't specify an encoding. */
private static final String DEFAULT_ENCODING = "UTF-8";
/** Encoding used for Java chars, used to parse Readers and Strings */
/*package*/ static final String CHARACTER_ENCODING = "UTF-16";
/** Timeout for HTTP connections (in ms) */
private static final int TIMEOUT = 20 * 1000;
/**
* Constructs a new parser with the specified encoding.
*/
/*package*/ ExpatParser(String encoding, ExpatReader xmlReader,
boolean processNamespaces, String publicId, String systemId) {
this.publicId = publicId;
this.systemId = systemId;
this.xmlReader = xmlReader;
/*
* TODO: Let Expat try to guess the encoding instead of defaulting.
* Unfortunately, I don't know how to tell which encoding Expat picked,
* so I won't know how to encode "<externalEntity>" below. The solution
* I think is to fix Expat to not require the "<externalEntity>"
* workaround.
*/
this.encoding = encoding == null ? DEFAULT_ENCODING : encoding;
this.pointer = initialize(
this.encoding,
processNamespaces
);
}
/**
* Used by {@link EntityParser}.
*/
private ExpatParser(String encoding, ExpatReader xmlReader, int pointer,
String publicId, String systemId) {
this.encoding = encoding;
this.xmlReader = xmlReader;
this.pointer = pointer;
this.systemId = systemId;
this.publicId = publicId;
}
/**
* Initializes native resources.
*
* @return the pointer to the native parser
*/
private native int initialize(String encoding, boolean namespacesEnabled);
/**
* Called at the start of an element.
*
* @param uri namespace URI of element or "" if namespace processing is
* disabled
* @param localName local name of element or "" if namespace processing is
* disabled
* @param qName qualified name or "" if namespace processing is enabled
* @param attributePointer pointer to native attribute char*--we keep
* a separate pointer so we can detach it from the parser instance
* @param attributeCount number of attributes
*/
/*package*/ void startElement(String uri, String localName, String qName,
int attributePointer, int attributeCount) throws SAXException {
ContentHandler contentHandler = xmlReader.contentHandler;
if (contentHandler == null) {
return;
}
try {
inStartElement = true;
this.attributePointer = attributePointer;
this.attributeCount = attributeCount;
contentHandler.startElement(
uri, localName, qName, this.attributes);
}
finally {
inStartElement = false;
this.attributeCount = -1;
this.attributePointer = 0;
}
}
/*package*/ void endElement(String uri, String localName, String qName)
throws SAXException {
ContentHandler contentHandler = xmlReader.contentHandler;
if (contentHandler != null) {
contentHandler.endElement(uri, localName, qName);
}
}
/*package*/ void text(char[] text, int length) throws SAXException {
ContentHandler contentHandler = xmlReader.contentHandler;
if (contentHandler != null) {
contentHandler.characters(text, 0, length);
}
}
/*package*/ void comment(char[] text, int length) throws SAXException {
LexicalHandler lexicalHandler = xmlReader.lexicalHandler;
if (lexicalHandler != null) {
lexicalHandler.comment(text, 0, length);
}
}
/*package*/ void startCdata() throws SAXException {
LexicalHandler lexicalHandler = xmlReader.lexicalHandler;
if (lexicalHandler != null) {
lexicalHandler.startCDATA();
}
}
/*package*/ void endCdata() throws SAXException {
LexicalHandler lexicalHandler = xmlReader.lexicalHandler;
if (lexicalHandler != null) {
lexicalHandler.endCDATA();
}
}
/*package*/ void startNamespace(String prefix, String uri)
throws SAXException {
ContentHandler contentHandler = xmlReader.contentHandler;
if (contentHandler != null) {
contentHandler.startPrefixMapping(prefix, uri);
}
}
/*package*/ void endNamespace(String prefix) throws SAXException {
ContentHandler contentHandler = xmlReader.contentHandler;
if (contentHandler != null) {
contentHandler.endPrefixMapping(prefix);
}
}
/*package*/ void startDtd(String name, String publicId, String systemId)
throws SAXException {
LexicalHandler lexicalHandler = xmlReader.lexicalHandler;
if (lexicalHandler != null) {
lexicalHandler.startDTD(name, publicId, systemId);
}
}
/*package*/ void endDtd() throws SAXException {
LexicalHandler lexicalHandler = xmlReader.lexicalHandler;
if (lexicalHandler != null) {
lexicalHandler.endDTD();
}
}
/*package*/ void processingInstruction(String target, String data)
throws SAXException {
ContentHandler contentHandler = xmlReader.contentHandler;
if (contentHandler != null) {
contentHandler.processingInstruction(target, data);
}
}
/**
* Handles an external entity.
*
* @param context to be passed back to Expat when we parse the entity
* @param publicId the publicId of the entity
* @param systemId the systemId of the entity
*/
/*package*/ void handleExternalEntity(String context, String publicId,
String systemId) throws SAXException, IOException {
EntityResolver entityResolver = xmlReader.entityResolver;
if (entityResolver == null) {
return;
}
/*
* The spec. is terribly under-specified here. It says that if the
* systemId is a URL, we should try to resolve it, but it doesn't
* specify how to tell whether or not the systemId is a URL let alone
* how to resolve it.
*
* Other implementations do various insane things. We try to keep it
* simple: if the systemId parses as a URI and it's relative, we try to
* resolve it against the parent document's systemId. If anything goes
* wrong, we go with the original systemId. If crazybob had designed
* the API, he would have left all resolving to the EntityResolver.
*/
if (this.systemId != null) {
try {
URI systemUri = new URI(systemId);
if (!systemUri.isAbsolute() && !systemUri.isOpaque()) {
// It could be relative (or it may not be a URI at all!)
URI baseUri = new URI(this.systemId);
systemUri = baseUri.resolve(systemUri);
// Replace systemId w/ resolved URI
systemId = systemUri.toString();
}
} catch (Exception e) {
Logger.getLogger(ExpatParser.class.getName()).log(Level.INFO,
"Could not resolve '" + systemId + "' relative to"
+ " '" + this.systemId + "' at " + locator, e);
}
}
InputSource inputSource = entityResolver.resolveEntity(
publicId, systemId);
if (inputSource == null) {
/*
* The spec. actually says that we should try to treat systemId
* as a URL and download and parse its contents here, but an
* entity resolver can easily accomplish the same by returning
* new InputSource(systemId).
*
* Downloading external entities by default would result in several
* unwanted DTD downloads, not to mention pose a security risk
* when parsing untrusted XML (http://tinyurl.com/56ggrk),
* so we just do nothing instead. This also enables the user to
* opt out of entity parsing when using
* {@link org.xml.sax.helpers.DefaultHandler}, something that
* wouldn't be possible otherwise.
*/
return;
}
String encoding = pickEncoding(inputSource);
int pointer = createEntityParser(this.pointer, context, encoding);
try {
EntityParser entityParser = new EntityParser(encoding, xmlReader,
pointer, inputSource.getPublicId(),
inputSource.getSystemId());
parseExternalEntity(entityParser, inputSource);
} finally {
releaseParser(pointer);
}
}
/**
* Picks an encoding for an external entity. Defaults to UTF-8.
*/
private String pickEncoding(InputSource inputSource) {
Reader reader = inputSource.getCharacterStream();
if (reader != null) {
return CHARACTER_ENCODING;
}
String encoding = inputSource.getEncoding();
return encoding == null ? DEFAULT_ENCODING : encoding;
}
/**
* Parses the the external entity provided by the input source.
*/
private void parseExternalEntity(ExpatParser entityParser,
InputSource inputSource) throws IOException, SAXException {
/*
* Expat complains if the external entity isn't wrapped with a root
* element so we add one and ignore it later on during parsing.
*/
// Try the character stream.
Reader reader = inputSource.getCharacterStream();
if (reader != null) {
try {
entityParser.append("<externalEntity>");
entityParser.parseFragment(reader);
entityParser.append("</externalEntity>");
} finally {
// TODO: Don't eat original exception when close() throws.
reader.close();
}
return;
}
// Try the byte stream.
InputStream in = inputSource.getByteStream();
if (in != null) {
try {
entityParser.append("<externalEntity>"
.getBytes(entityParser.encoding));
entityParser.parseFragment(in);
entityParser.append("</externalEntity>"
.getBytes(entityParser.encoding));
} finally {
// TODO: Don't eat original exception when close() throws.
in.close();
}
return;
}
// Make sure we use the user-provided systemId.
String systemId = inputSource.getSystemId();
if (systemId == null) {
// TODO: We could just try our systemId here.
throw new ParseException("No input specified.", locator);
}
// Try the system id.
in = openUrl(systemId);
try {
entityParser.append("<externalEntity>"
.getBytes(entityParser.encoding));
entityParser.parseFragment(in);
entityParser.append("</externalEntity>"
.getBytes(entityParser.encoding));
} finally {
in.close();
}
}
/**
* Creates a native entity parser.
*
* @param parentPointer pointer to parent Expat parser
* @param context passed to {@link #handleExternalEntity}
* @param encoding
* @return pointer to native parser
*/
private static native int createEntityParser(int parentPointer,
String context, String encoding);
/**
* Appends part of an XML document. This parser will parse the given XML to
* the extent possible and dispatch to the appropriate methods.
*
* @param xml a whole or partial snippet of XML
* @throws SAXException if an error occurs during parsing
*/
/*package*/ void append(String xml) throws SAXException {
try {
append(this.pointer, xml, false);
} catch (ExpatException e) {
throw new ParseException(e.getMessage(), this.locator);
}
}
private native void append(int pointer, String xml, boolean isFinal)
throws SAXException, ExpatException;
/**
* Appends part of an XML document. This parser will parse the given XML to
* the extent possible and dispatch to the appropriate methods.
*
* @param xml a whole or partial snippet of XML
* @param offset into the char[]
* @param length of characters to use
* @throws SAXException if an error occurs during parsing
*/
/*package*/ void append(char[] xml, int offset, int length)
throws SAXException {
try {
append(this.pointer, xml, offset, length);
} catch (ExpatException e) {
throw new ParseException(e.getMessage(), this.locator);
}
}
private native void append(int pointer, char[] xml, int offset,
int length) throws SAXException, ExpatException;
/**
* Appends part of an XML document. This parser will parse the given XML to
* the extent possible and dispatch to the appropriate methods.
*
* @param xml a whole or partial snippet of XML
* @throws SAXException if an error occurs during parsing
*/
/*package*/ void append(byte[] xml) throws SAXException {
append(xml, 0, xml.length);
}
/**
* Appends part of an XML document. This parser will parse the given XML to
* the extent possible and dispatch to the appropriate methods.
*
* @param xml a whole or partial snippet of XML
* @param offset into the byte[]
* @param length of bytes to use
* @throws SAXException if an error occurs during parsing
*/
/*package*/ void append(byte[] xml, int offset, int length)
throws SAXException {
try {
append(this.pointer, xml, offset, length);
} catch (ExpatException e) {
throw new ParseException(e.getMessage(), this.locator);
}
}
private native void append(int pointer, byte[] xml, int offset,
int length) throws SAXException, ExpatException;
/**
* Parses an XML document from the given input stream.
*/
/*package*/ void parseDocument(InputStream in) throws IOException,
SAXException {
startDocument();
parseFragment(in);
finish();
endDocument();
}
/**
* Parses an XML Document from the given reader.
*/
/*package*/ void parseDocument(Reader in) throws IOException, SAXException {
startDocument();
parseFragment(in);
finish();
endDocument();
}
/**
* Parses XML from the given Reader.
*/
private void parseFragment(Reader in) throws IOException, SAXException {
char[] buffer = new char[BUFFER_SIZE / 2];
int length;
while ((length = in.read(buffer)) != -1) {
try {
append(this.pointer, buffer, 0, length);
} catch (ExpatException e) {
throw new ParseException(e.getMessage(), locator);
}
}
}
/**
* Parses XML from the given input stream.
*/
private void parseFragment(InputStream in)
throws IOException, SAXException {
byte[] buffer = new byte[BUFFER_SIZE];
int length;
while ((length = in.read(buffer)) != -1) {
try {
append(this.pointer, buffer, 0, length);
} catch (ExpatException e) {
throw new ParseException(e.getMessage(), this.locator);
}
}
}
private void startDocument() throws SAXException {
ContentHandler contentHandler = xmlReader.contentHandler;
if (contentHandler != null) {
contentHandler.setDocumentLocator(this.locator);
contentHandler.startDocument();
}
}
private void endDocument() throws SAXException {
ContentHandler contentHandler;
contentHandler = xmlReader.contentHandler;
if (contentHandler != null) {
contentHandler.endDocument();
}
}
/**
* Indicate that we're finished parsing.
*
* @throws SAXException if the xml is incomplete
*/
/*package*/ void finish() throws SAXException {
try {
append(this.pointer, "", true);
} catch (ExpatException e) {
throw new ParseException(e.getMessage(), this.locator);
}
}
@Override
@SuppressWarnings("FinalizeDoesntCallSuperFinalize")
protected synchronized void finalize() throws Throwable {
if (this.pointer != 0) {
release(this.pointer);
this.pointer = 0;
}
}
/**
* Releases all native objects.
*/
private native void release(int pointer);
/**
* Releases native parser only.
*/
private static native void releaseParser(int pointer);
/**
* Initialize static resources.
*/
private static native void staticInitialize(String emptyString);
static {
staticInitialize("");
}
/**
* Gets the current line number within the XML file.
*/
private int line() {
return line(this.pointer);
}
private static native int line(int pointer);
/**
* Gets the current column number within the XML file.
*/
private int column() {
return column(this.pointer);
}
private static native int column(int pointer);
/**
* Clones the current attributes so they can be used outside of
* startElement().
*/
/*package*/ Attributes cloneAttributes() {
if (!inStartElement) {
throw new IllegalStateException(OUTSIDE_START_ELEMENT);
}
if (attributeCount == 0) {
return ClonedAttributes.EMPTY;
}
int clonePointer
= cloneAttributes(this.attributePointer, this.attributeCount);
return new ClonedAttributes(pointer, clonePointer, attributeCount);
}
private static native int cloneAttributes(int pointer, int attributeCount);
/**
* Used for cloned attributes.
*/
private static class ClonedAttributes extends ExpatAttributes {
private static final Attributes EMPTY = new ClonedAttributes(0, 0, 0);
private final int parserPointer;
private int pointer;
private final int length;
/**
* Constructs a Java wrapper for native attributes.
*
* @param parserPointer pointer to the parse, can be 0 if length is 0.
* @param pointer pointer to the attributes array, can be 0 if the
* length is 0.
* @param length number of attributes
*/
private ClonedAttributes(int parserPointer, int pointer, int length) {
this.parserPointer = parserPointer;
this.pointer = pointer;
this.length = length;
}
@Override
public int getParserPointer() {
return this.parserPointer;
}
@Override
public int getPointer() {
return pointer;
}
@Override
public int getLength() {
return length;
}
@Override
@SuppressWarnings("FinalizeDoesntCallSuperFinalize")
protected synchronized void finalize() throws Throwable {
if (pointer != 0) {
freeAttributes(pointer);
pointer = 0;
}
}
}
private class ExpatLocator implements Locator {
public String getPublicId() {
return publicId;
}
public String getSystemId() {
return systemId;
}
public int getLineNumber() {
return line();
}
public int getColumnNumber() {
return column();
}
@Override
public String toString() {
return "Locator[publicId: " + publicId + ", systemId: " + systemId
+ ", line: " + getLineNumber()
+ ", column: " + getColumnNumber() + "]";
}
}
/**
* Attributes that are only valid during startElement().
*/
private class CurrentAttributes extends ExpatAttributes {
@Override
public int getParserPointer() {
return pointer;
}
@Override
public int getPointer() {
if (!inStartElement) {
throw new IllegalStateException(OUTSIDE_START_ELEMENT);
}
return attributePointer;
}
@Override
public int getLength() {
if (!inStartElement) {
throw new IllegalStateException(OUTSIDE_START_ELEMENT);
}
return attributeCount;
}
}
/**
* Includes line and column in the message.
*/
private static class ParseException extends SAXParseException {
private ParseException(String message, Locator locator) {
super(makeMessage(message, locator), locator);
}
private static String makeMessage(String message, Locator locator) {
return makeMessage(message, locator.getLineNumber(),
locator.getColumnNumber());
}
private static String makeMessage(
String message, int line, int column) {
return "At line " + line + ", column "
+ column + ": " + message;
}
}
/**
* Opens an InputStream for the given URL.
*/
/*package*/ static InputStream openUrl(String url) throws IOException {
try {
URLConnection urlConnection = new URL(url).openConnection();
urlConnection.setConnectTimeout(TIMEOUT);
urlConnection.setReadTimeout(TIMEOUT);
urlConnection.setDoInput(true);
urlConnection.setDoOutput(false);
return urlConnection.getInputStream();
} catch (Exception e) {
IOException ioe = new IOException("Couldn't open " + url);
ioe.initCause(e);
throw ioe;
}
}
/**
* Parses an external entity.
*/
private static class EntityParser extends ExpatParser {
private int depth = 0;
private EntityParser(String encoding, ExpatReader xmlReader,
int pointer, String publicId, String systemId) {
super(encoding, xmlReader, pointer, publicId, systemId);
}
@Override
void startElement(String uri, String localName, String qName,
int attributePointer, int attributeCount) throws SAXException {
/*
* Skip topmost element generated by our workaround in
* {@link #handleExternalEntity}.
*/
if (depth++ > 0) {
super.startElement(uri, localName, qName, attributePointer,
attributeCount);
}
}
@Override
void endElement(String uri, String localName, String qName)
throws SAXException {
if (--depth > 0) {
super.endElement(uri, localName, qName);
}
}
@Override
@SuppressWarnings("FinalizeDoesntCallSuperFinalize")
protected synchronized void finalize() throws Throwable {
/*
* Don't release our native resources. We do so explicitly in
* {@link #handleExternalEntity} and we don't want to release the
* parsing context--our parent is using it.
*/
}
}
}
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