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/**************************************************************************/
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/* Copyright (c) 2001, 2007 NoMachine, http://www.nomachine.com/. */
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/* NXCOMP, NX protocol compression and NX extensions to this software */
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/* are copyright of NoMachine. Redistribution and use of the present */
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/* software is allowed according to terms specified in the file LICENSE */
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/* which comes in the source distribution. */
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/* Check http://www.nomachine.com/licensing.html for applicability. */
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/* NX and NoMachine are trademarks of NoMachine S.r.l. */
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/* All rights reserved. */
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/**************************************************************************/
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#include "ReadBuffer.h"
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#include "Transport.h"
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// Set the verbosity level.
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ReadBuffer::ReadBuffer(Transport *transport)
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: transport_(transport)
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// The read buffer will grow until
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// reaching the maximum buffer size
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// and then will remain stable at
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initialReadSize_ = READ_BUFFER_DEFAULT_SIZE;
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maximumBufferSize_ = READ_BUFFER_DEFAULT_SIZE;
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ReadBuffer::~ReadBuffer()
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void ReadBuffer::readMessage(const unsigned char *message, unsigned int length)
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// To be here we must be the real owner
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// of the buffer and there must not be
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// pending bytes in the transport.
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*logofs << "ReadBuffer: PANIC! Class for FD#"
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<< transport_ -> fd() << " doesn't "
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<< "appear to be the owner of the buffer "
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<< "while borrowing from the caller.\n"
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// Be sure that any outstanding data from
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// the transport is appended to our own
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if (transport_ -> pending() != 0)
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*logofs << "ReadBuffer: WARNING! Class for FD#"
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<< transport_ -> fd() << " has pending "
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<< "data in the transport while "
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<< "borrowing from the caller.\n"
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// Can't borrow the buffer if there is data
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// from a partial message. In this case add
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// the new data to the end of our buffer.
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*logofs << "ReadBuffer: Borrowing " << length
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<< " bytes from the caller for FD#"
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<< transport_ -> fd() << " with "
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<< length_ << " bytes in the buffer.\n"
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buffer_ = (unsigned char *) message;
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*logofs << "ReadBuffer: Appending " << length
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<< " bytes from the caller for FD#"
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<< transport_ -> fd() << " with "
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<< length_ << " bytes in the buffer.\n"
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appendBuffer(message, length);
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int ReadBuffer::readMessage()
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int pendingLength = transport_ -> pending();
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if (pendingLength > 0)
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// Can't move the data in the borrowed buffer,
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// so use the tansport buffer only if we don't
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// have any partial message. This can happen
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// with the proxy where we need to deflate the
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unsigned char *newBuffer;
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length_ = transport_ -> getPending(newBuffer);
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if (newBuffer == NULL)
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*logofs << "ReadBuffer: PANIC! Failed to borrow "
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<< length_ << " bytes of memory for buffer "
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<< "in context [A].\n" << logofs_flush;
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cerr << "Error" << ": Failed to borrow memory for "
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<< "read buffer in context [A].\n";
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*logofs << "ReadBuffer: Borrowed " << length_
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<< " pending bytes for FD#" << transport_ ->
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fd() << ".\n" << logofs_flush;
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*logofs << "ReadBuffer: WARNING! Cannot borrow "
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<< pendingLength << " bytes for FD#"
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<< transport_ -> fd() << " with "
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<< length_ << " bytes in the buffer.\n"
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unsigned int readLength = suggestedLength(pendingLength);
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*logofs << "ReadBuffer: Requested " << readLength
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<< " bytes for FD#" << transport_ -> fd()
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<< " with readable " << transport_ -> readable()
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<< " remaining " << remaining_ << " pending "
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<< transport_ -> pending() << ".\n"
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if (readLength < initialReadSize_)
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readLength = initialReadSize_;
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*logofs << "ReadBuffer: Buffer size is " << size_
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<< " length " << length_ << " and start "
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<< start_ << ".\n" << logofs_flush;
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// We can't use the transport buffer
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// to read our own data in it.
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*logofs << "ReadBuffer: PANIC! Class for FD#"
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<< transport_ -> fd() << " doesn't "
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<< "appear to be the owner of the buffer "
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<< "while reading.\n" << logofs_flush;
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// Be sure that we have enough space
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// to store all the requested data.
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if (buffer_ == NULL || length_ + readLength > size_)
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unsigned int newSize = length_ + readLength;
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*logofs << "ReadBuffer: Resizing buffer for FD#"
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<< transport_ -> fd() << " in read from "
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<< size_ << " to " << newSize << " bytes.\n"
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unsigned char *newBuffer = allocateBuffer(newSize);
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memcpy(newBuffer, buffer_ + start_, length_);
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transport_ -> pendingReset();
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else if (start_ != 0 && length_ != 0)
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// If any bytes are left due to a partial
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// message, shift them to the beginning
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*logofs << "ReadBuffer: Moving " << length_
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<< " bytes of data " << "at beginning of "
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<< "the buffer for FD#" << transport_ -> fd()
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<< ".\n" << logofs_flush;
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memmove(buffer_, buffer_ + start_, length_);
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*logofs << "ReadBuffer: Buffer size is now " << size_
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<< " length is " << length_ << " and start is "
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<< start_ << ".\n" << logofs_flush;
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unsigned char *readData = buffer_ + length_;
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*logofs << "ReadBuffer: Going to read " << readLength
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<< " bytes from FD#" << transport_ -> fd() << ".\n"
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int bytesRead = transport_ -> read(readData, readLength);
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*logofs << "ReadBuffer: Read " << bytesRead
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<< " bytes from FD#" << transport_ -> fd()
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<< ".\n" << logofs_flush;
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length_ += bytesRead;
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else if (bytesRead < 0)
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// Check if there is more data pending than the
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// size of the provided buffer. After reading
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// the requested amount, in fact, the transport
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// may have decompressed the data and produced
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// more input. This trick allows us to always
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// borrow the buffer from the transport, even
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// when the partial read would have prevented
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if (transport_ -> pending() > 0)
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*logofs << "ReadBuffer: WARNING! Trying to read some "
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<< "more with " << transport_ -> pending()
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<< " bytes pending for FD#" << transport_ ->
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fd() << ".\n" << logofs_flush;
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return readMessage();
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*logofs << "ReadBuffer: Error detected reading "
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<< "from FD#" << transport_ -> fd()
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<< ".\n" << logofs_flush;
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*logofs << "ReadBuffer: No data read from FD#"
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<< transport_ -> fd() << " with remaining "
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<< remaining_ << ".\n" << logofs_flush;
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const unsigned char *ReadBuffer::getMessage(unsigned int &controlLength,
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unsigned int &dataLength)
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if (transport_ -> pending() > 0)
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*logofs << "ReadBuffer: PANIC! The transport "
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<< "appears to have data pending.\n"
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*logofs << "ReadBuffer: No message can be located "
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<< "for FD#" << transport_ -> fd() << ".\n"
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transport_ -> pendingReset();
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unsigned int trailerLength;
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*logofs << "ReadBuffer: Going to locate message with "
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<< "start at " << start_ << " and length "
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<< length_ << " for FD#" << transport_ -> fd()
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<< ".\n" << logofs_flush;
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int located = locateMessage(buffer_ + start_, buffer_ + start_ + length_,
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controlLength, dataLength, trailerLength);
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// No more complete messages are in
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*logofs << "ReadBuffer: No message was located "
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<< "for FD#" << transport_ -> fd()
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<< ".\n" << logofs_flush;
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// Must move the remaining bytes in
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const unsigned char *result = buffer_ + start_;
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// Message contains data, so go to the
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// first byte of payload.
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result += trailerLength;
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start_ += (dataLength + trailerLength);
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length_ -= (dataLength + trailerLength);
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// It is a control message.
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start_ += (controlLength + trailerLength);
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length_ -= (controlLength + trailerLength);
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*logofs << "ReadBuffer: Located message for FD#"
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<< transport_ -> fd() << " with control length "
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<< controlLength << " and data length "
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<< dataLength << ".\n" << logofs_flush;
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int ReadBuffer::setSize(int initialReadSize, int maximumBufferSize)
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initialReadSize_ = initialReadSize;
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maximumBufferSize_ = maximumBufferSize;
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*logofs << "ReadBuffer: WARNING! Set buffer parameters to "
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<< initialReadSize_ << "/" << maximumBufferSize_
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<< " for object at "<< this << ".\n"
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void ReadBuffer::fullReset()
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*logofs << "ReadBuffer: PANIC! Class for FD#"
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<< transport_ -> fd() << " doesn't "
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<< "appear to be the owner of the buffer "
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<< "in reset.\n" << logofs_flush;
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if (length_ == 0 && size_ > maximumBufferSize_)
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*logofs << "ReadBuffer: Resizing buffer for FD#"
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<< transport_ -> fd() << " in reset from "
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<< size_ << " to " << maximumBufferSize_
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<< " bytes.\n" << logofs_flush;
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int newSize = maximumBufferSize_;
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unsigned char *newBuffer = allocateBuffer(newSize);
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transport_ -> pendingReset();
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unsigned char *ReadBuffer::allocateBuffer(unsigned int newSize)
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unsigned char *newBuffer = new unsigned char[newSize];
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if (newBuffer == NULL)
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*logofs << "ReadBuffer: PANIC! Can't allocate "
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<< newSize << " bytes of memory for buffer "
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<< "in context [B].\n" << logofs_flush;
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cerr << "Error" << ": Can't allocate memory for "
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<< "read buffer in context [B].\n";
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memset(newBuffer, '\0', newSize);
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void ReadBuffer::appendBuffer(const unsigned char *message, unsigned int length)
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if (start_ + length_ + length > size_)
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unsigned int newSize = length_ + length + initialReadSize_;
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*logofs << "ReadBuffer: WARNING! Resizing buffer "
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<< "for FD#" << transport_ -> fd()
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<< " from " << size_ << " to " << newSize
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<< " bytes.\n" << logofs_flush;
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unsigned char *newBuffer = allocateBuffer(newSize);
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memcpy(newBuffer, buffer_ + start_, length_);
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memcpy(buffer_ + start_ + length_, message, length);
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transport_ -> pendingReset();
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void ReadBuffer::convertBuffer()
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unsigned int newSize = length_ + initialReadSize_;
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*logofs << "ReadBuffer: WARNING! Converting "
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<< length_ << " bytes to own buffer "
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<< "for FD#" << transport_ -> fd()
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<< " with new size " << newSize
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<< " bytes.\n" << logofs_flush;
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unsigned char *newBuffer = allocateBuffer(newSize);
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memcpy(newBuffer, buffer_ + start_, length_);
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transport_ -> pendingReset();
added
removed
ReadBuffer.cpp
