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Provides a streaming API to access attachments parts in a MIME message.
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 1997-2015 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* http://glassfish.java.net/public/CDDL+GPL_1_1.html
* or packager/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at packager/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
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*/
package org.jvnet.mimepull;
import java.io.InputStream;
import java.io.IOException;
import java.util.*;
import java.util.logging.Logger;
import java.nio.ByteBuffer;
import java.util.logging.Level;
/**
* Pull parser for the MIME messages. Applications can use pull API to continue
* the parsing MIME messages lazily.
*
*
* for e.g.:
*
*
* MIMEParser parser = ...
* Iterator it = parser.iterator();
* while(it.hasNext()) {
* MIMEEvent event = it.next();
* ...
* }
*
*
* @author Jitendra Kotamraju
*/
class MIMEParser implements Iterable {
private static final Logger LOGGER = Logger.getLogger(MIMEParser.class.getName());
private static final String HEADER_ENCODING = "ISO8859-1";
// Actually, the grammar doesn't support whitespace characters
// after boundary. But the mail implementation checks for it.
// We will only check for these many whitespace characters after boundary
private static final int NO_LWSP = 1000;
private enum STATE {START_MESSAGE, SKIP_PREAMBLE, START_PART, HEADERS, BODY, END_PART, END_MESSAGE}
private STATE state = STATE.START_MESSAGE;
private final InputStream in;
private final byte[] bndbytes;
private final int bl;
private final MIMEConfig config;
private final int[] bcs = new int[128]; // BnM algo: Bad Character Shift table
private final int[] gss; // BnM algo : Good Suffix Shift table
/**
* Have we parsed the data from our InputStream yet?
*/
private boolean parsed;
/*
* Read and process body partsList until we see the
* terminating boundary line (or EOF).
*/
private boolean done = false;
private boolean eof;
private final int capacity;
private byte[] buf;
private int len;
private boolean bol; // beginning of the line
/*
* Parses the MIME content. At the EOF, it also closes input stream
*/
MIMEParser(InputStream in, String boundary, MIMEConfig config) {
this.in = in;
this.bndbytes = getBytes("--"+boundary);
bl = bndbytes.length;
this.config = config;
gss = new int[bl];
compileBoundaryPattern();
// \r\n + boundary + "--\r\n" + lots of LWSP
capacity = config.chunkSize+2+bl+4+NO_LWSP;
createBuf(capacity);
}
/**
* Returns iterator for the parsing events. Use the iterator to advance
* the parsing.
*
* @return iterator for parsing events
*/
@Override
public Iterator iterator() {
return new MIMEEventIterator();
}
class MIMEEventIterator implements Iterator {
@Override
public boolean hasNext() {
return !parsed;
}
@Override
public MIMEEvent next() {
if (parsed) {
throw new NoSuchElementException();
}
switch(state) {
case START_MESSAGE :
if (LOGGER.isLoggable(Level.FINER)) {LOGGER.log(Level.FINER, "MIMEParser state={0}", STATE.START_MESSAGE);}
state = STATE.SKIP_PREAMBLE;
return MIMEEvent.START_MESSAGE;
case SKIP_PREAMBLE :
if (LOGGER.isLoggable(Level.FINER)) {LOGGER.log(Level.FINER, "MIMEParser state={0}", STATE.SKIP_PREAMBLE);}
skipPreamble();
// fall through
case START_PART :
if (LOGGER.isLoggable(Level.FINER)) {LOGGER.log(Level.FINER, "MIMEParser state={0}", STATE.START_PART);}
state = STATE.HEADERS;
return MIMEEvent.START_PART;
case HEADERS :
if (LOGGER.isLoggable(Level.FINER)) {LOGGER.log(Level.FINER, "MIMEParser state={0}", STATE.HEADERS);}
InternetHeaders ih = readHeaders();
state = STATE.BODY;
bol = true;
return new MIMEEvent.Headers(ih);
case BODY :
if (LOGGER.isLoggable(Level.FINER)) {LOGGER.log(Level.FINER, "MIMEParser state={0}", STATE.BODY);}
ByteBuffer buf = readBody();
bol = false;
return new MIMEEvent.Content(buf);
case END_PART :
if (LOGGER.isLoggable(Level.FINER)) {LOGGER.log(Level.FINER, "MIMEParser state={0}", STATE.END_PART);}
if (done) {
state = STATE.END_MESSAGE;
} else {
state = STATE.START_PART;
}
return MIMEEvent.END_PART;
case END_MESSAGE :
if (LOGGER.isLoggable(Level.FINER)) {LOGGER.log(Level.FINER, "MIMEParser state={0}", STATE.END_MESSAGE);}
parsed = true;
return MIMEEvent.END_MESSAGE;
default :
throw new MIMEParsingException("Unknown Parser state = "+state);
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
/**
* Collects the headers for the current part by parsing mesage stream.
*
* @return headers for the current part
*/
private InternetHeaders readHeaders() {
if (!eof) {
fillBuf();
}
return new InternetHeaders(new LineInputStream());
}
/**
* Reads and saves the part of the current attachment part's content.
* At the end of this method, buf should have the remaining data
* at index 0.
*
* @return a chunk of the part's content
*
*/
private ByteBuffer readBody() {
if (!eof) {
fillBuf();
}
int start = match(buf, 0, len); // matches boundary
if (start == -1) {
// No boundary is found
assert eof || len >= config.chunkSize;
int chunkSize = eof ? len : config.chunkSize;
if (eof) {
done = true;
throw new MIMEParsingException("Reached EOF, but there is no closing MIME boundary.");
}
return adjustBuf(chunkSize, len-chunkSize);
}
// Found boundary.
// Is it at the start of a line ?
int chunkLen = start;
if (bol && start == 0) {
// nothing to do
} else if (start > 0 && (buf[start-1] == '\n' || buf[start-1] =='\r')) {
--chunkLen;
if (buf[start-1] == '\n' && start >1 && buf[start-2] == '\r') {
--chunkLen;
}
} else {
return adjustBuf(start+1, len-start-1); // boundary is not at beginning of a line
}
if (start+bl+1 < len && buf[start+bl] == '-' && buf[start+bl+1] == '-') {
state = STATE.END_PART;
done = true;
return adjustBuf(chunkLen, 0);
}
// Consider all the whitespace in boundary+whitespace+"\r\n"
int lwsp = 0;
for(int i=start+bl; i < len && (buf[i] == ' ' || buf[i] == '\t'); i++) {
++lwsp;
}
// Check for \n or \r\n in boundary+whitespace+"\n" or boundary+whitespace+"\r\n"
if (start+bl+lwsp < len && buf[start+bl+lwsp] == '\n') {
state = STATE.END_PART;
return adjustBuf(chunkLen, len-start-bl-lwsp-1);
} else if (start+bl+lwsp+1 < len && buf[start+bl+lwsp] == '\r' && buf[start+bl+lwsp+1] == '\n') {
state = STATE.END_PART;
return adjustBuf(chunkLen, len-start-bl-lwsp-2);
} else if (start+bl+lwsp+1 < len) {
return adjustBuf(chunkLen+1, len-chunkLen-1); // boundary string in a part data
} else if (eof) {
done = true;
throw new MIMEParsingException("Reached EOF, but there is no closing MIME boundary.");
}
// Some more data needed to determine if it is indeed a proper boundary
return adjustBuf(chunkLen, len-chunkLen);
}
/**
* Returns a chunk from the original buffer. A new buffer is
* created with the remaining bytes.
*
* @param chunkSize create a chunk with these many bytes
* @param remaining bytes from the end of the buffer that need to be copied to
* the beginning of the new buffer
* @return chunk
*/
private ByteBuffer adjustBuf(int chunkSize, int remaining) {
assert buf != null;
assert chunkSize >= 0;
assert remaining >= 0;
byte[] temp = buf;
// create a new buf and adjust it without this chunk
createBuf(remaining);
System.arraycopy(temp, len-remaining, buf, 0, remaining);
len = remaining;
return ByteBuffer.wrap(temp, 0, chunkSize);
}
private void createBuf(int min) {
buf = new byte[min < capacity ? capacity : min];
}
/**
* Skips the preamble to find the first attachment part
*/
private void skipPreamble() {
while(true) {
if (!eof) {
fillBuf();
}
int start = match(buf, 0, len); // matches boundary
if (start == -1) {
// No boundary is found
if (eof) {
throw new MIMEParsingException("Missing start boundary");
} else {
adjustBuf(len-bl+1, bl-1);
continue;
}
}
if (start > config.chunkSize) {
adjustBuf(start, len-start);
continue;
}
// Consider all the whitespace boundary+whitespace+"\r\n"
int lwsp = 0;
for(int i=start+bl; i < len && (buf[i] == ' ' || buf[i] == '\t'); i++) {
++lwsp;
}
// Check for \n or \r\n
if (start+bl+lwsp < len && (buf[start+bl+lwsp] == '\n' || buf[start+bl+lwsp] == '\r') ) {
if (buf[start+bl+lwsp] == '\n') {
adjustBuf(start+bl+lwsp+1, len-start-bl-lwsp-1);
break;
} else if (start+bl+lwsp+1 < len && buf[start+bl+lwsp+1] == '\n') {
adjustBuf(start+bl+lwsp+2, len-start-bl-lwsp-2);
break;
}
}
adjustBuf(start+1, len-start-1);
}
if (LOGGER.isLoggable(Level.FINE)) {LOGGER.log(Level.FINE, "Skipped the preamble. buffer len={0}", len);}
}
private static byte[] getBytes(String s) {
char [] chars= s.toCharArray();
int size = chars.length;
byte[] bytes = new byte[size];
for (int i = 0; i < size;) {
bytes[i] = (byte) chars[i++];
}
return bytes;
}
/**
* Boyer-Moore search method. Copied from java.util.regex.Pattern.java
*
* Pre calculates arrays needed to generate the bad character
* shift and the good suffix shift. Only the last seven bits
* are used to see if chars match; This keeps the tables small
* and covers the heavily used ASCII range, but occasionally
* results in an aliased match for the bad character shift.
*/
private void compileBoundaryPattern() {
int i, j;
// Precalculate part of the bad character shift
// It is a table for where in the pattern each
// lower 7-bit value occurs
for (i = 0; i < bndbytes.length; i++) {
bcs[bndbytes[i]&0x7F] = i + 1;
}
// Precalculate the good suffix shift
// i is the shift amount being considered
NEXT: for (i = bndbytes.length; i > 0; i--) {
// j is the beginning index of suffix being considered
for (j = bndbytes.length - 1; j >= i; j--) {
// Testing for good suffix
if (bndbytes[j] == bndbytes[j-i]) {
// src[j..len] is a good suffix
gss[j-1] = i;
} else {
// No match. The array has already been
// filled up with correct values before.
continue NEXT;
}
}
// This fills up the remaining of optoSft
// any suffix can not have larger shift amount
// then its sub-suffix. Why???
while (j > 0) {
gss[--j] = i;
}
}
// Set the guard value because of unicode compression
gss[bndbytes.length -1] = 1;
}
/**
* Finds the boundary in the given buffer using Boyer-Moore algo.
* Copied from java.util.regex.Pattern.java
*
* @param mybuf boundary to be searched in this mybuf
* @param off start index in mybuf
* @param len number of bytes in mybuf
*
* @return -1 if there is no match or index where the match starts
*/
private int match(byte[] mybuf, int off, int len) {
int last = len - bndbytes.length;
// Loop over all possible match positions in text
NEXT: while (off <= last) {
// Loop over pattern from right to left
for (int j = bndbytes.length - 1; j >= 0; j--) {
byte ch = mybuf[off+j];
if (ch != bndbytes[j]) {
// Shift search to the right by the maximum of the
// bad character shift and the good suffix shift
off += Math.max(j + 1 - bcs[ch&0x7F], gss[j]);
continue NEXT;
}
}
// Entire pattern matched starting at off
return off;
}
return -1;
}
/**
* Fills the remaining buf to the full capacity
*/
private void fillBuf() {
if (LOGGER.isLoggable(Level.FINER)) {LOGGER.log(Level.FINER, "Before fillBuf() buffer len={0}", len);}
assert !eof;
while(len < buf.length) {
int read;
try {
read = in.read(buf, len, buf.length-len);
} catch(IOException ioe) {
throw new MIMEParsingException(ioe);
}
if (read == -1) {
eof = true;
try {
if (LOGGER.isLoggable(Level.FINE)) {LOGGER.fine("Closing the input stream.");}
in.close();
} catch(IOException ioe) {
throw new MIMEParsingException(ioe);
}
break;
} else {
len += read;
}
}
if (LOGGER.isLoggable(Level.FINER)) {LOGGER.log(Level.FINER, "After fillBuf() buffer len={0}", len);}
}
private void doubleBuf() {
byte[] temp = new byte[2*len];
System.arraycopy(buf, 0, temp, 0, len);
buf = temp;
if (!eof) {
fillBuf();
}
}
class LineInputStream {
private int offset;
/*
* Read a line containing only ASCII characters from the input
* stream. A line is terminated by a CR or NL or CR-NL sequence.
* A common error is a CR-CR-NL sequence, which will also terminate
* a line.
* The line terminator is not returned as part of the returned
* String. Returns null if no data is available.
*
* This class is similar to the deprecated
* DataInputStream.readLine()
*/
public String readLine() throws IOException {
int hdrLen = 0;
int lwsp = 0;
while(offset+hdrLen < len) {
if (buf[offset+hdrLen] == '\n') {
lwsp = 1;
break;
}
if (offset+hdrLen+1 == len) {
doubleBuf();
}
if (offset+hdrLen+1 >= len) { // No more data in the stream
assert eof;
return null;
}
if (buf[offset+hdrLen] == '\r' && buf[offset+hdrLen+1] == '\n') {
lwsp = 2;
break;
}
++hdrLen;
}
if (hdrLen == 0) {
adjustBuf(offset+lwsp, len-offset-lwsp);
return null;
}
String hdr = new String(buf, offset, hdrLen, HEADER_ENCODING);
offset += hdrLen+lwsp;
return hdr;
}
}
}
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