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Resolved issue: NETTY-102: Allow DelimiterBasedFrameDecoder to include the delimiter in the frame.

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* Added stripDelimiter option
* Much more efficient and accurate handling of discarding the frame that exceeds maxFrameLength
This commit is contained in:
Trustin Lee 2009-01-06 05:11:55 +00:00
parent c460c90dea
commit 7ea187df89
1 changed files with 80 additions and 15 deletions
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95
src/main/java/org/jboss/netty/handler/codec/frame/DelimiterBasedFrameDecoder.java
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@ -74,6 +74,9 @@ public class DelimiterBasedFrameDecoder extends FrameDecoder {
private final ChannelBuffer[] delimiters;
private final int maxFrameLength;
private final boolean stripDelimiter;
private volatile boolean discardingTooLongFrame;
private volatile long tooLongFrameLength;
/**
* Creates a new instance.
@ -84,6 +87,21 @@ public class DelimiterBasedFrameDecoder extends FrameDecoder {
* @param delimiter the delimiter
*/
public DelimiterBasedFrameDecoder(int maxFrameLength, ChannelBuffer delimiter) {
this(maxFrameLength, true, delimiter);
}
/**
* Creates a new instance.
*
* @param maxFrameLength the maximum length of the decoded frame.
* A {@link TooLongFrameException} is thrown if
* the length of the frame exceeds this value.
* @param stripDelimiter whether the decoded frame should strip out the
* delimiter or not
* @param delimiter the delimiter
*/
public DelimiterBasedFrameDecoder(
int maxFrameLength, boolean stripDelimiter, ChannelBuffer delimiter) {
validateMaxFrameLength(maxFrameLength);
validateDelimiter(delimiter);
delimiters = new ChannelBuffer[] {
@ -91,6 +109,7 @@ public class DelimiterBasedFrameDecoder extends FrameDecoder {
delimiter.readerIndex(), delimiter.readableBytes())
};
this.maxFrameLength = maxFrameLength;
this.stripDelimiter = stripDelimiter;
}
/**
@ -102,6 +121,21 @@ public class DelimiterBasedFrameDecoder extends FrameDecoder {
* @param delimiters the delimiters
*/
public DelimiterBasedFrameDecoder(int maxFrameLength, ChannelBuffer... delimiters) {
this(maxFrameLength, true, delimiters);
}
/**
* Creates a new instance.
*
* @param maxFrameLength the maximum length of the decoded frame.
* A {@link TooLongFrameException} is thrown if
* the length of the frame exceeds this value.
* @param stripDelimiter whether the decoded frame should strip out the
* delimiter or not
* @param delimiters the delimiters
*/
public DelimiterBasedFrameDecoder(
int maxFrameLength, boolean stripDelimiter, ChannelBuffer... delimiters) {
validateMaxFrameLength(maxFrameLength);
if (delimiters == null) {
throw new NullPointerException("delimiters");
@ -116,42 +150,73 @@ public class DelimiterBasedFrameDecoder extends FrameDecoder {
this.delimiters[i] = d.slice(d.readerIndex(), d.readableBytes());
}
this.maxFrameLength = maxFrameLength;
this.stripDelimiter = stripDelimiter;
}
@Override
protected Object decode(
ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) throws Exception {
// Try all delimiters and choose the delimiter which yields the shortest frame.
int minDelimIndex = Integer.MAX_VALUE;
int minFrameLength = Integer.MAX_VALUE;
ChannelBuffer minDelim = null;
for (ChannelBuffer delim: delimiters) {
int delimIndex = indexOf(buffer, delim);
if (delimIndex >= 0 && delimIndex < minDelimIndex) {
minDelimIndex = delimIndex;
int frameLength = indexOf(buffer, delim);
if (frameLength >= 0 && frameLength < minFrameLength) {
minFrameLength = frameLength;
minDelim = delim;
}
}
if (minDelim != null) {
ChannelBuffer frame = buffer.readBytes(minDelimIndex);
if (frame.readableBytes() > maxFrameLength) {
fail(frame.readableBytes());
}
buffer.skipBytes(minDelim.capacity());
return frame;
}
int minDelimLength = minDelim.capacity();
ChannelBuffer frame;
if (buffer.readableBytes() > maxFrameLength) {
fail(buffer.readableBytes());
if (discardingTooLongFrame) {
// We've just finished discarding a very large frame.
// Throw an exception and go back to the initial state.
long tooLongFrameLength = this.tooLongFrameLength;
this.tooLongFrameLength = 0L;
discardingTooLongFrame = false;
buffer.skipBytes(minFrameLength + minDelimLength);
fail(tooLongFrameLength + minFrameLength + minDelimLength);
}
if (minFrameLength > maxFrameLength) {
// Discard read frame.
buffer.skipBytes(minFrameLength + minDelimLength);
fail(minFrameLength);
}
if (stripDelimiter) {
frame = buffer.readBytes(minFrameLength);
buffer.skipBytes(minDelimLength);
} else {
frame = buffer.readBytes(minFrameLength + minDelimLength);
}
return frame;
} else {
if (buffer.readableBytes() > maxFrameLength) {
// Discard the content of the buffer until a delimiter is found.
tooLongFrameLength = buffer.readableBytes();
buffer.skipBytes(buffer.readableBytes());
discardingTooLongFrame = true;
}
return null;
}
return null;
}
private void fail(int frameLength) throws TooLongFrameException {
private void fail(long frameLength) throws TooLongFrameException {
throw new TooLongFrameException(
"The frame length exceeds " + maxFrameLength + ": " + frameLength);
}
/**
* Returns the number of bytes between the readerIndex of the haystack and
* the first needle found in the haystack. -1 is returned if no needle is
* found in the haystack.
*/
private static int indexOf(ChannelBuffer haystack, ChannelBuffer needle) {
for (int i = haystack.readerIndex(); i < haystack.writerIndex(); i ++) {
int haystackIndex = i;