com.lowagie.text.xml.simpleparser.SimpleXMLParser Maven / Gradle / Ivy
/*
* Copyright 2003 Paulo Soares
*
* The contents of this file are subject to the Mozilla Public License Version 1.1
* (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the License.
*
* The Original Code is 'iText, a free JAVA-PDF library'.
*
* The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
* the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
* All Rights Reserved.
* Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
* are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
*
* Contributor(s): all the names of the contributors are added in the source code
* where applicable.
*
* Alternatively, the contents of this file may be used under the terms of the
* LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
* provisions of LGPL are applicable instead of those above. If you wish to
* allow use of your version of this file only under the terms of the LGPL
* License and not to allow others to use your version of this file under
* the MPL, indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by the LGPL.
* If you do not delete the provisions above, a recipient may use your version
* of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the MPL as stated above or under the terms of the GNU
* Library General Public License as published by the Free Software Foundation;
* either version 2 of the License, or any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Library general Public License for more
* details.
*
*/
package com.lowagie.text.xml.simpleparser;
import com.lowagie.text.error_messages.MessageLocalization;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.charset.UnsupportedCharsetException;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.Stack;
/**
* A simple XML and HTML parser. This parser is, like the SAX parser,
* an event based parser, but with much less functionality.
*
* The parser can:
*
*
* - It recognizes the encoding used
*
- It recognizes all the elements' start tags and end tags
*
- It lists attributes, where attribute values can be enclosed in single or double quotes
*
- It recognizes the
<[CDATA[ ... ]]> construct
* - It recognizes the standard entities: &, <, >, ", and ', as well as numeric entities
*
- It maps lines ending in
\r\n and \r to \n on input, in accordance with the XML Specification, Section 2.11
*
*/
public final class SimpleXMLParser {
/** possible states */
private final static int UNKNOWN = 0;
private final static int TEXT = 1;
private final static int TAG_ENCOUNTERED = 2;
private final static int EXAMIN_TAG = 3;
private final static int TAG_EXAMINED = 4;
private final static int IN_CLOSETAG = 5;
private final static int SINGLE_TAG = 6;
private final static int CDATA = 7;
private final static int COMMENT = 8;
private final static int PI = 9;
private final static int ENTITY = 10;
private final static int QUOTE = 11;
private final static int ATTRIBUTE_KEY = 12;
private final static int ATTRIBUTE_EQUAL = 13;
private final static int ATTRIBUTE_VALUE = 14;
/** the state stack */
Stack stack;
/** The current character. */
int character = 0;
/** The previous character. */
int previousCharacter = -1;
/** the line we are currently reading */
int lines = 1;
/** the column where the current character occurs */
int columns = 0;
/** was the last character equivalent to a newline? */
boolean eol = false;
/**
* A boolean indicating if the next character should be taken into account
* if it's a space character. When nospace is false, the previous character
* wasn't whitespace.
* @since 2.1.5
*/
boolean nowhite = false;
/** the current state */
int state;
/** Are we parsing HTML? */
boolean html;
/** current text (whatever is encountered between tags) */
StringBuffer text = new StringBuffer();
/** current entity (whatever is encountered between & and ;) */
StringBuffer entity = new StringBuffer();
/** current tagname */
String tag = null;
/** current attributes */
Map attributes = null;
/** The handler to which we are going to forward document content */
SimpleXMLDocHandler doc;
/** The handler to which we are going to forward comments. */
SimpleXMLDocHandlerComment comment;
/** Keeps track of the number of tags that are open. */
int nested = 0;
/** the quote character that was used to open the quote. */
int quoteCharacter = '"';
/** the attribute key. */
String attributekey = null;
/** the attribute value. */
String attributevalue = null;
/**
* Creates a Simple XML parser object.
* Call go(BufferedReader) immediately after creation.
*/
private SimpleXMLParser(SimpleXMLDocHandler doc, SimpleXMLDocHandlerComment comment, boolean html) {
this.doc = doc;
this.comment = comment;
this.html = html;
stack = new Stack<>();
state = html ? TEXT : UNKNOWN;
}
/**
* Does the actual parsing. Perform this immediately
* after creating the parser object.
*/
private void go(Reader r) throws IOException {
BufferedReader reader;
if (r instanceof BufferedReader)
reader = (BufferedReader)r;
else
reader = new BufferedReader(r);
doc.startDocument();
while(true) {
// read a new character
if (previousCharacter == -1) {
character = reader.read();
}
// or re-examine the previous character
else {
character = previousCharacter;
previousCharacter = -1;
}
// the end of the file was reached
if (character == -1) {
if (html) {
if (html && state == TEXT)
flush();
doc.endDocument();
} else {
throwException(MessageLocalization.getComposedMessage("missing.end.tag"));
}
return;
}
// dealing with \n and \r
if (character == '\n' && eol) {
eol = false;
continue;
} else if (eol) {
eol = false;
} else if (character == '\n') {
lines++;
columns = 0;
} else if (character == '\r') {
eol = true;
character = '\n';
lines++;
columns = 0;
} else {
columns++;
}
switch(state) {
// we are in an unknown state before there's actual content
case UNKNOWN:
if(character == '<') {
saveState(TEXT);
state = TAG_ENCOUNTERED;
}
break;
// we can encounter any content
case TEXT:
if(character == '<') {
flush();
saveState(state);
state = TAG_ENCOUNTERED;
} else if(character == '&') {
saveState(state);
entity.setLength(0);
state = ENTITY;
nowhite = true;
} else if (Character.isWhitespace((char)character)) {
if (nowhite)
text.append((char)character);
nowhite = false;
} else {
text.append((char)character);
nowhite = true;
}
break;
// we have just seen a < and are wondering what we are looking at
// , , , etc.
case TAG_ENCOUNTERED:
initTag();
if(character == '/') {
state = IN_CLOSETAG;
} else if (character == '?') {
restoreState();
state = PI;
} else {
text.append((char)character);
state = EXAMIN_TAG;
}
break;
// we are processing something like this .
// It could still be a or something.
case EXAMIN_TAG:
if(character == '>') {
doTag();
processTag(true);
initTag();
state = restoreState();
} else if(character == '/') {
state = SINGLE_TAG;
} else if(character == '-' && text.toString().equals("!-")) {
flush();
state = COMMENT;
} else if(character == '[' && text.toString().equals("![CDATA")) {
flush();
state = CDATA;
} else if(character == 'E' && text.toString().equals("!DOCTYP")) {
flush();
state = PI;
} else if(Character.isWhitespace((char)character)) {
doTag();
state = TAG_EXAMINED;
} else {
text.append((char)character);
}
break;
// we know the name of the tag now.
case TAG_EXAMINED:
if(character == '>') {
processTag(true);
initTag();
state = restoreState();
} else if(character == '/') {
state = SINGLE_TAG;
} else if(Character.isWhitespace((char)character)) {
// empty
} else {
text.append((char)character);
state = ATTRIBUTE_KEY;
}
break;
// we are processing a closing tag: e.g.
case IN_CLOSETAG:
if(character == '>') {
doTag();
processTag(false);
if(!html && nested==0) return;
state = restoreState();
} else {
if (!Character.isWhitespace((char)character))
text.append((char)character);
}
break;
// we have just seen something like this: .
case SINGLE_TAG:
if(character != '>')
throwException(MessageLocalization.getComposedMessage("expected.gt.for.tag.lt.1.gt", tag));
doTag();
processTag(true);
processTag(false);
initTag();
if(!html && nested==0) {
doc.endDocument();
return;
}
state = restoreState();
break;
// we are processing CDATA
case CDATA:
if(character == '>'
&& text.toString().endsWith("]]")) {
text.setLength(text.length()-2);
flush();
state = restoreState();
} else
text.append((char)character);
break;
// we are processing a comment. We are inside
// the looking for the -->.
case COMMENT:
if(character == '>'
&& text.toString().endsWith("--")) {
text.setLength(text.length() - 2);
flush();
state = restoreState();
} else
text.append((char)character);
break;
// We are inside one of these or one of these
case PI:
if(character == '>') {
state = restoreState();
if(state == TEXT) state = UNKNOWN;
}
break;
// we are processing an entity, e.g. <, », etc.
case ENTITY:
if(character == ';') {
state = restoreState();
String cent = entity.toString();
entity.setLength(0);
char ce = EntitiesToUnicode.decodeEntity(cent);
if (ce == '\0')
text.append('&').append(cent).append(';');
else
text.append(ce);
} else if ((character != '#' && (character < '0' || character > '9') && (character < 'a' || character > 'z')
&& (character < 'A' || character > 'Z')) || entity.length() >= 7) {
state = restoreState();
previousCharacter = character;
text.append('&').append(entity.toString());
entity.setLength(0);
}
else {
entity.append((char)character);
}
break;
// We are processing the quoted right-hand side of an element's attribute.
case QUOTE:
if (html && quoteCharacter == ' ' && character == '>') {
flush();
processTag(true);
initTag();
state = restoreState();
}
else if (html && quoteCharacter == ' ' && Character.isWhitespace((char)character)) {
flush();
state = TAG_EXAMINED;
}
else if (html && quoteCharacter == ' ') {
text.append((char) character);
} else if (character == quoteCharacter) {
flush();
state = TAG_EXAMINED;
} else if (" \r\n\t".indexOf(character) >= 0) {
text.append(' ');
} else if (character == '&') {
saveState(state);
state = ENTITY;
entity.setLength(0);
} else {
text.append((char) character);
}
break;
case ATTRIBUTE_KEY:
if(Character.isWhitespace((char)character)) {
flush();
state = ATTRIBUTE_EQUAL;
} else if(character == '=') {
flush();
state = ATTRIBUTE_VALUE;
} else if (html && character == '>') {
text.setLength(0);
processTag(true);
initTag();
state = restoreState();
} else {
text.append((char)character);
}
break;
case ATTRIBUTE_EQUAL:
if(character == '=') {
state = ATTRIBUTE_VALUE;
} else if(Character.isWhitespace((char)character)) {
// empty
} else if (html && character == '>') {
text.setLength(0);
processTag(true);
initTag();
state = restoreState();
} else if (html && character == '/') {
flush();
state = SINGLE_TAG;
} else if (html) {
flush();
text.append((char)character);
state = ATTRIBUTE_KEY;
} else {
throwException(MessageLocalization.getComposedMessage("error.in.attribute.processing"));
}
break;
case ATTRIBUTE_VALUE:
if(character == '"' || character == '\'') {
quoteCharacter = character;
state = QUOTE;
} else if(Character.isWhitespace((char)character)) {
// empty
} else if (html && character == '>') {
flush();
processTag(true);
initTag();
state = restoreState();
} else if (html) {
text.append((char)character);
quoteCharacter = ' ';
state = QUOTE;
} else {
throwException(MessageLocalization.getComposedMessage("error.in.attribute.processing"));
}
break;
}
}
}
/**
* Gets a state from the stack
* @return the previous state
*/
private int restoreState() {
if(!stack.empty())
return stack.pop();
else
return UNKNOWN;
}
/**
* Adds a state to the stack.
* @param s a state to add to the stack
*/
private void saveState(int s) {
stack.push(s);
}
/**
* Flushes the text that is currently in the buffer.
* The text can be ignored, added to the document
* as content or as comment,... depending on the current state.
*/
private void flush() {
switch(state){
case TEXT:
case CDATA:
if(text.length() > 0) {
doc.text(text.toString());
}
break;
case COMMENT:
if (comment != null) {
comment.comment(text.toString());
}
break;
case ATTRIBUTE_KEY:
attributekey = text.toString();
if (html)
attributekey = attributekey.toLowerCase();
break;
case QUOTE:
case ATTRIBUTE_VALUE:
attributevalue = text.toString();
attributes.put(attributekey, attributevalue);
break;
default:
// do nothing
}
text.setLength(0);
}
/**
* Initialized the tag name and attributes.
*/
private void initTag() {
tag = null;
attributes = new HashMap<>();
}
/** Sets the name of the tag. */
private void doTag() {
if(tag == null)
tag = text.toString();
if (html)
tag = tag.toLowerCase();
text.setLength(0);
}
/**
* processes the tag.
* @param start if true we are dealing with a tag that has just been opened; if false we are closing a tag.
*/
private void processTag(boolean start) {
if (start) {
nested++;
doc.startElement(tag, attributes);
}
else {
nested--;
doc.endElement(tag);
}
}
/** Throws an exception */
private void throwException(String s) throws IOException {
throw new IOException(MessageLocalization.getComposedMessage("1.near.line.2.column.3", s, String.valueOf(lines), String.valueOf(columns)));
}
/**
* Parses the XML document firing the events to the handler.
* @param doc the document handler
* @param comment {@link SimpleXMLParser#comment}
* @param r the document. The encoding is already resolved. The reader is not closed
* @param html {@link SimpleXMLParser#html}
* @throws IOException on error
*/
public static void parse(SimpleXMLDocHandler doc, SimpleXMLDocHandlerComment comment, Reader r, boolean html) throws IOException {
SimpleXMLParser parser = new SimpleXMLParser(doc, comment, html);
parser.go(r);
}
/** Detect charset from BOM, as per Unicode FAQ. */
private static Optional detectCharsetFromBOM(byte[] bom) {
// 00 00 FE FF UTF-32BE
// EF BB BF .. UTF-8
// FE FF .. .. UTF-16BE
// FF FE 00 00 UTF-32LE
// FF FE .. .. UTF-16LE
switch (bom[0]) {
case (byte) 0x00:
if (bom[1] == (byte) 0x00 && bom[2] == (byte) 0xFE && bom[3] == (byte) 0xFF)
return Optional.of(Charset.forName("UTF-32BE"));
break;
case (byte) 0xEF:
if (bom[1] == (byte) 0xBB && bom[2] == (byte) 0xBF)
return Optional.of(StandardCharsets.UTF_8);
break;
case (byte) 0xFE:
if (bom[1] == (byte) 0xFF)
return Optional.of(StandardCharsets.UTF_16BE);
break;
case (byte) 0xFF:
if (bom[1] == (byte) 0xFE) {
if (bom[2] == (byte) 0x00 && bom[3] == (byte) 0x00)
return Optional.of(Charset.forName("UTF-32LE"));
else
return Optional.of(StandardCharsets.UTF_16LE);
}
break;
}
return Optional.empty();
}
/**
* Parses the XML document firing the events to the handler.
* @param doc the document handler
* @param in the document. The encoding is deduced from the stream. The stream is not closed
* @throws IOException on error
*/
public static void parse(SimpleXMLDocHandler doc, InputStream in) throws IOException {
byte[] b4 = new byte[4];
int count = in.read(b4);
if (count != 4)
throw new IOException(MessageLocalization.getComposedMessage("insufficient.length"));
Charset encoding = detectCharsetFromBOM(b4).orElse(null);
if (encoding == null) {
StringBuilder sb = new StringBuilder();
int c;
while ((c = in.read()) != -1) {
if (c == '>')
break;
sb.append((char)c);
}
String decl = getDeclaredEncoding(sb.toString());
if (decl == null)
encoding = StandardCharsets.UTF_8;
else
try {
encoding = Charset.forName(decl);
} catch (UnsupportedCharsetException e) {
encoding = Charset.forName(IanaEncodings.getJavaEncoding(decl));
}
}
parse(doc, new InputStreamReader(in, encoding));
}
private static String getDeclaredEncoding(String decl) {
if (decl == null)
return null;
int idx = decl.indexOf("encoding");
if (idx < 0)
return null;
int idx1 = decl.indexOf('"', idx);
int idx2 = decl.indexOf('\'', idx);
if (idx1 == idx2)
return null;
if ((idx1 < 0 && idx2 > 0) || (idx2 > 0 && idx2 < idx1)) {
int idx3 = decl.indexOf('\'', idx2 + 1);
if (idx3 < 0)
return null;
return decl.substring(idx2 + 1, idx3);
}
if ((idx2 < 0 && idx1 > 0) || (idx1 > 0 && idx1 < idx2)) {
int idx3 = decl.indexOf('"', idx1 + 1);
if (idx3 < 0)
return null;
return decl.substring(idx1 + 1, idx3);
}
return null;
}
public static void parse(SimpleXMLDocHandler doc,Reader r) throws IOException {
parse(doc, null, r, false);
}
}