com.sun.mail.iap.ResponseInputStream Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package com.sun.mail.iap;
import java.io.*;
import com.sun.mail.iap.ByteArray;
import com.sun.mail.util.ASCIIUtility;
/**
*
* Inputstream that is used to read a Response.
*
* @author Arun Krishnan
* @author Bill Shannon
*/
public class ResponseInputStream {
private static final int minIncrement = 256;
private static final int maxIncrement = 256 * 1024;
private static final int incrementSlop = 16;
// where we read from
private BufferedInputStream bin;
/**
* Constructor.
*
* @param in the InputStream to wrap
*/
public ResponseInputStream(InputStream in) {
bin = new BufferedInputStream(in, 2 * 1024);
}
/**
* Read a Response from the InputStream.
*
* @return ByteArray that contains the Response
* @exception IOException for I/O errors
*/
public ByteArray readResponse() throws IOException {
return readResponse(null);
}
/**
* Read a Response from the InputStream.
*
* @param ba the ByteArray in which to store the response, or null
* @return ByteArray that contains the Response
* @exception IOException for I/O errors
*/
public ByteArray readResponse(ByteArray ba) throws IOException {
if (ba == null)
ba = new ByteArray(new byte[128], 0, 128);
byte[] buffer = ba.getBytes();
int idx = 0;
for (;;) { // read until CRLF with no preceeding literal
// XXX - b needs to be an int, to handle bytes with value 0xff
int b = 0;
boolean gotCRLF=false;
// Read a CRLF terminated line from the InputStream
while (!gotCRLF &&
((b = bin.read()) != -1)) {
if (b == '\n') {
if ((idx > 0) && buffer[idx-1] == '\r')
gotCRLF = true;
}
if (idx >= buffer.length) {
int incr = buffer.length;
if (incr > maxIncrement)
incr = maxIncrement;
ba.grow(incr);
buffer = ba.getBytes();
}
buffer[idx++] = (byte)b;
}
if (b == -1)
throw new IOException("Connection dropped by server?");
// Now lets check for literals : {}CRLF
// Note: index needs to >= 5 for the above sequence to occur
if (idx < 5 || buffer[idx-3] != '}')
break;
int i;
// look for left curly
for (i = idx - 4; i >= 0; i--)
if (buffer[i] == '{')
break;
if (i < 0) // Nope, not a literal ?
break;
int count = 0;
// OK, handle the literal ..
try {
count = ASCIIUtility.parseInt(buffer, i+1, idx-3);
} catch (NumberFormatException e) {
break;
}
// Now read 'count' bytes. (Note: count could be 0)
if (count > 0) {
int avail = buffer.length - idx; // available space in buffer
if (count + incrementSlop > avail) {
// need count-avail more bytes
ba.grow(minIncrement > count + incrementSlop - avail ?
minIncrement : count + incrementSlop - avail);
buffer = ba.getBytes();
}
/*
* read() might not return all the bytes in one shot,
* so call repeatedly till we are done
*/
int actual;
while (count > 0) {
actual = bin.read(buffer, idx, count);
if (actual == -1)
throw new IOException("Connection dropped by server?");
count -= actual;
idx += actual;
}
}
// back to top of loop to read until CRLF
}
ba.setCount(idx);
return ba;
}
/**
* How much buffered data do we have?
*
* @return number of bytes available
* @exception IOException if the stream has been closed
* @since JavaMail 1.5.4
*/
public int available() throws IOException {
return bin.available();
}
}