316 lines
9.6 KiB
C++
316 lines
9.6 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
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** All rights reserved.
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** Contact: http://www.qt-project.org/
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**
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** This file is part of the QtCore module of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:LGPL$
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** GNU Lesser General Public License Usage
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** This file may be used under the terms of the GNU Lesser General Public
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** License version 2.1 as published by the Free Software Foundation and
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** appearing in the file LICENSE.LGPL included in the packaging of this
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** file. Please review the following information to ensure the GNU Lesser
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** General Public License version 2.1 requirements will be met:
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** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
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**
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** In addition, as a special exception, Nokia gives you certain additional
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** rights. These rights are described in the Nokia Qt LGPL Exception
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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**
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** GNU General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU General
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** Public License version 3.0 as published by the Free Software Foundation
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** and appearing in the file LICENSE.GPL included in the packaging of this
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** file. Please review the following information to ensure the GNU General
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** Public License version 3.0 requirements will be met:
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** http://www.gnu.org/copyleft/gpl.html.
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**
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** Other Usage
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** Alternatively, this file may be used in accordance with the terms and
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** conditions contained in a signed written agreement between you and Nokia.
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**
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**
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**
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**
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include "qwindowspipereader_p.h"
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#include <qdebug.h>
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#include <qelapsedtimer.h>
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#include <qeventloop.h>
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#include <qtimer.h>
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#include <qwineventnotifier.h>
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QT_BEGIN_NAMESPACE
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QWindowsPipeReader::QWindowsPipeReader(QObject *parent)
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: QObject(parent),
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handle(INVALID_HANDLE_VALUE),
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readBufferMaxSize(0),
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actualReadBufferSize(0),
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emitReadyReadTimer(new QTimer(this)),
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pipeBroken(false)
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{
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emitReadyReadTimer->setSingleShot(true);
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connect(emitReadyReadTimer, SIGNAL(timeout()), SIGNAL(readyRead()));
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ZeroMemory(&overlapped, sizeof(overlapped));
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overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
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dataReadNotifier = new QWinEventNotifier(overlapped.hEvent, this);
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connect(dataReadNotifier, SIGNAL(activated(HANDLE)), SLOT(readEventSignalled()));
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}
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QWindowsPipeReader::~QWindowsPipeReader()
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{
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CloseHandle(overlapped.hEvent);
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}
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/*!
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Sets the handle to read from. The handle must be valid.
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*/
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void QWindowsPipeReader::setHandle(HANDLE hPipeReadEnd)
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{
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readBuffer.clear();
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actualReadBufferSize = 0;
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handle = hPipeReadEnd;
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pipeBroken = false;
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dataReadNotifier->setEnabled(true);
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}
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/*!
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Stops the asynchronous read sequence.
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This function assumes that the file already has been closed.
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It does not cancel any I/O operation.
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*/
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void QWindowsPipeReader::stop()
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{
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dataReadNotifier->setEnabled(false);
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readSequenceStarted = false;
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handle = INVALID_HANDLE_VALUE;
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ResetEvent(overlapped.hEvent);
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}
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/*!
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Returns the number of bytes we've read so far.
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*/
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qint64 QWindowsPipeReader::bytesAvailable() const
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{
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return actualReadBufferSize;
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}
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/*!
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Stops the asynchronous read sequence.
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*/
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qint64 QWindowsPipeReader::read(char *data, qint64 maxlen)
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{
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if (pipeBroken && actualReadBufferSize == 0)
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return -1; // signal EOF
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qint64 readSoFar;
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// If startAsyncRead() has read data, copy it to its destination.
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if (maxlen == 1 && actualReadBufferSize > 0) {
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*data = readBuffer.getChar();
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actualReadBufferSize--;
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readSoFar = 1;
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} else {
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qint64 bytesToRead = qMin(qint64(actualReadBufferSize), maxlen);
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readSoFar = 0;
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while (readSoFar < bytesToRead) {
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const char *ptr = readBuffer.readPointer();
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int bytesToReadFromThisBlock = qMin(bytesToRead - readSoFar,
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qint64(readBuffer.nextDataBlockSize()));
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memcpy(data + readSoFar, ptr, bytesToReadFromThisBlock);
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readSoFar += bytesToReadFromThisBlock;
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readBuffer.free(bytesToReadFromThisBlock);
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actualReadBufferSize -= bytesToReadFromThisBlock;
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}
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}
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if (!pipeBroken) {
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if (!actualReadBufferSize)
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emitReadyReadTimer->stop();
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if (!readSequenceStarted)
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startAsyncRead();
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}
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return readSoFar;
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}
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bool QWindowsPipeReader::canReadLine() const
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{
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return readBuffer.indexOf('\n', actualReadBufferSize) >= 0;
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}
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/*!
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\internal
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Will be called whenever the read operation completes.
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Returns true, if readyRead() has been emitted.
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*/
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bool QWindowsPipeReader::readEventSignalled()
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{
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if (!completeAsyncRead()) {
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pipeBroken = true;
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emit pipeClosed();
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return false;
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}
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startAsyncRead();
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emitReadyReadTimer->stop();
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emit readyRead();
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return true;
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}
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/*!
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\internal
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Reads data from the socket into the readbuffer
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*/
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void QWindowsPipeReader::startAsyncRead()
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{
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do {
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DWORD bytesToRead = checkPipeState();
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if (pipeBroken)
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return;
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if (bytesToRead == 0) {
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// There are no bytes in the pipe but we need to
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// start the overlapped read with some buffer size.
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bytesToRead = initialReadBufferSize;
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}
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if (readBufferMaxSize && bytesToRead > (readBufferMaxSize - readBuffer.size())) {
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bytesToRead = readBufferMaxSize - readBuffer.size();
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if (bytesToRead == 0) {
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// Buffer is full. User must read data from the buffer
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// before we can read more from the pipe.
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return;
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}
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}
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char *ptr = readBuffer.reserve(bytesToRead);
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readSequenceStarted = true;
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if (ReadFile(handle, ptr, bytesToRead, NULL, &overlapped)) {
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completeAsyncRead();
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} else {
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switch (GetLastError()) {
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case ERROR_IO_PENDING:
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// This is not an error. We're getting notified, when data arrives.
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return;
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case ERROR_MORE_DATA:
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// This is not an error. The synchronous read succeeded.
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// We're connected to a message mode pipe and the message
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// didn't fit into the pipe's system buffer.
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completeAsyncRead();
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break;
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case ERROR_PIPE_NOT_CONNECTED:
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{
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// It may happen, that the other side closes the connection directly
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// after writing data. Then we must set the appropriate socket state.
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pipeBroken = true;
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emit pipeClosed();
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return;
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}
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default:
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emit winError(GetLastError(), QLatin1String("QWindowsPipeReader::startAsyncRead"));
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return;
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}
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}
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} while (!readSequenceStarted);
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}
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/*!
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\internal
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Sets the correct size of the read buffer after a read operation.
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Returns false, if an error occurred or the connection dropped.
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*/
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bool QWindowsPipeReader::completeAsyncRead()
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{
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ResetEvent(overlapped.hEvent);
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readSequenceStarted = false;
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DWORD bytesRead;
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if (!GetOverlappedResult(handle, &overlapped, &bytesRead, TRUE)) {
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switch (GetLastError()) {
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case ERROR_MORE_DATA:
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// This is not an error. We're connected to a message mode
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// pipe and the message didn't fit into the pipe's system
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// buffer. We will read the remaining data in the next call.
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break;
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case ERROR_BROKEN_PIPE:
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case ERROR_PIPE_NOT_CONNECTED:
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return false;
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default:
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emit winError(GetLastError(), QLatin1String("QWindowsPipeReader::completeAsyncRead"));
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return false;
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}
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}
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actualReadBufferSize += bytesRead;
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readBuffer.truncate(actualReadBufferSize);
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if (!emitReadyReadTimer->isActive())
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emitReadyReadTimer->start();
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return true;
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}
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/*!
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\internal
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Returns the number of available bytes in the pipe.
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Sets QWindowsPipeReader::pipeBroken to true if the connection is broken.
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*/
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DWORD QWindowsPipeReader::checkPipeState()
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{
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DWORD bytes;
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if (PeekNamedPipe(handle, NULL, 0, NULL, &bytes, NULL)) {
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return bytes;
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} else {
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if (!pipeBroken) {
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pipeBroken = true;
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emit pipeClosed();
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}
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}
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return 0;
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}
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/*!
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Waits for the completion of the asynchronous read operation.
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Returns true, if we've emitted the readyRead signal.
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*/
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bool QWindowsPipeReader::waitForReadyRead(int msecs)
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{
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Q_ASSERT(readSequenceStarted);
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DWORD result = WaitForSingleObject(overlapped.hEvent, msecs == -1 ? INFINITE : msecs);
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switch (result) {
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case WAIT_OBJECT_0:
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return readEventSignalled();
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case WAIT_TIMEOUT:
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return false;
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}
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qWarning("QWindowsPipeReader::waitForReadyRead WaitForSingleObject failed with error code %d.", int(GetLastError()));
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return false;
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}
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/*!
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Waits until the pipe is closed.
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*/
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bool QWindowsPipeReader::waitForPipeClosed(int msecs)
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{
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const int sleepTime = 10;
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QElapsedTimer stopWatch;
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stopWatch.start();
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forever {
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checkPipeState();
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if (pipeBroken)
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return true;
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if (stopWatch.hasExpired(msecs - sleepTime))
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return false;
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Sleep(sleepTime);
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}
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}
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QT_END_NAMESPACE
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