/**************************************************************************** ** ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). ** Contact: Nokia Corporation (qt-info@nokia.com) ** ** This file is part of the QtCore module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** No Commercial Usage ** This file contains pre-release code and may not be distributed. ** You may use this file in accordance with the terms and conditions ** contained in the Technology Preview License Agreement accompanying ** this package. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 2.1 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 2.1 requirements ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. ** ** In addition, as a special exception, Nokia gives you certain ** additional rights. These rights are described in the Nokia Qt LGPL ** Exception version 1.1, included in the file LGPL_EXCEPTION.txt in this ** package. ** ** If you have questions regarding the use of this file, please contact ** Nokia at qt-info@nokia.com. ** ** ** ** ** ** ** ** ** $QT_END_LICENSE$ ** ****************************************************************************/ //#define QIODEVICE_DEBUG #include "qbytearray.h" #include "qdebug.h" #include "qiodevice_p.h" #include "qfile.h" #include "qstringlist.h" #include QT_BEGIN_NAMESPACE #ifdef QIODEVICE_DEBUG void debugBinaryString(const QByteArray &input) { QByteArray tmp; int startOffset = 0; for (int i = 0; i < input.size(); ++i) { tmp += input[i]; if ((i % 16) == 15 || i == (input.size() - 1)) { printf("\n%15d:", startOffset); startOffset += tmp.size(); for (int j = 0; j < tmp.size(); ++j) printf(" %02x", int(uchar(tmp[j]))); for (int j = tmp.size(); j < 16 + 1; ++j) printf(" "); for (int j = 0; j < tmp.size(); ++j) printf("%c", isprint(int(uchar(tmp[j]))) ? tmp[j] : '.'); tmp.clear(); } } printf("\n\n"); } void debugBinaryString(const char *data, qint64 maxlen) { debugBinaryString(QByteArray(data, maxlen)); } #endif #ifndef QIODEVICE_BUFFERSIZE #define QIODEVICE_BUFFERSIZE Q_INT64_C(16384) #endif #define Q_VOID #define CHECK_MAXLEN(function, returnType) \ do { \ if (maxSize < 0) { \ qWarning("QIODevice::"#function": Called with maxSize < 0"); \ return returnType; \ } \ } while (0) #define CHECK_WRITABLE(function, returnType) \ do { \ if ((d->openMode & WriteOnly) == 0) { \ if (d->openMode == NotOpen) \ return returnType; \ qWarning("QIODevice::"#function": ReadOnly device"); \ return returnType; \ } \ } while (0) #define CHECK_READABLE(function, returnType) \ do { \ if ((d->openMode & ReadOnly) == 0) { \ if (d->openMode == NotOpen) \ return returnType; \ qWarning("QIODevice::"#function": WriteOnly device"); \ return returnType; \ } \ } while (0) /*! \internal */ QIODevicePrivate::QIODevicePrivate() : openMode(QIODevice::NotOpen), buffer(QIODEVICE_BUFFERSIZE), pos(0), devicePos(0), accessMode(Unset) { } /*! \internal */ QIODevicePrivate::~QIODevicePrivate() { } /*! \class QIODevice \reentrant \brief The QIODevice class is the base interface class of all I/O devices in Qt. \ingroup io QIODevice provides both a common implementation and an abstract interface for devices that support reading and writing of blocks of data, such as QFile, QBuffer and QTcpSocket. QIODevice is abstract and can not be instantiated, but it is common to use the interface it defines to provide device-independent I/O features. For example, Qt's XML classes operate on a QIODevice pointer, allowing them to be used with various devices (such as files and buffers). Before accessing the device, open() must be called to set the correct OpenMode (such as ReadOnly or ReadWrite). You can then write to the device with write() or putChar(), and read by calling either read(), readLine(), or readAll(). Call close() when you are done with the device. QIODevice distinguishes between two types of devices: random-access devices and sequential devices. \list \o Random-access devices support seeking to arbitrary positions using seek(). The current position in the file is available by calling pos(). QFile and QBuffer are examples of random-access devices. \o Sequential devices don't support seeking to arbitrary positions. The data must be read in one pass. The functions pos() and size() don't work for sequential devices. QTcpSocket and QProcess are examples of sequential devices. \endlist You can use isSequential() to determine the type of device. QIODevice emits readyRead() when new data is available for reading; for example, if new data has arrived on the network or if additional data is appended to a file that you are reading from. You can call bytesAvailable() to determine the number of bytes that are currently available for reading. It's common to use bytesAvailable() together with the readyRead() signal when programming with asynchronous devices such as QTcpSocket, where fragments of data can arrive at arbitrary points in time. QIODevice emits the bytesWritten() signal every time a payload of data has been written to the device. Use bytesToWrite() to determine the current amount of data waiting to be written. Certain subclasses of QIODevice, such as QTcpSocket and QProcess, are asynchronous. This means that I/O functions such as write() or read() always return immediately, while communication with the device itself may happen when control goes back to the event loop. QIODevice provides functions that allow you to force these operations to be performed immediately, while blocking the calling thread and without entering the event loop. This allows QIODevice subclasses to be used without an event loop, or in a separate thread: \list \o waitForReadyRead() - This function suspends operation in the calling thread until new data is available for reading. \o waitForBytesWritten() - This function suspends operation in the calling thread until one payload of data has been written to the device. \o waitFor....() - Subclasses of QIODevice implement blocking functions for device-specific operations. For example, QProcess has a function called waitForStarted() which suspends operation in the calling thread until the process has started. \endlist Calling these functions from the main, GUI thread, may cause your user interface to freeze. Example: \snippet doc/src/snippets/code/src_corelib_io_qiodevice.cpp 0 By subclassing QIODevice, you can provide the same interface to your own I/O devices. Subclasses of QIODevice are only required to implement the protected readData() and writeData() functions. QIODevice uses these functions to implement all its convenience functions, such as getChar(), readLine() and write(). QIODevice also handles access control for you, so you can safely assume that the device is opened in write mode if writeData() is called. Some subclasses, such as QFile and QTcpSocket, are implemented using a memory buffer for intermediate storing of data. This reduces the number of required device accessing calls, which are often very slow. Buffering makes functions like getChar() and putChar() fast, as they can operate on the memory buffer instead of directly on the device itself. Certain I/O operations, however, don't work well with a buffer. For example, if several users open the same device and read it character by character, they may end up reading the same data when they meant to read a separate chunk each. For this reason, QIODevice allows you to bypass any buffering by passing the Unbuffered flag to open(). When subclassing QIODevice, remember to bypass any buffer you may use when the device is open in Unbuffered mode. \sa QBuffer QFile QTcpSocket */ /*! \typedef QIODevice::Offset \compat Use \c qint64 instead. */ /*! \typedef QIODevice::Status \compat Use QIODevice::OpenMode instead, or see the documentation for specific devices. */ /*! \enum QIODevice::OpenModeFlag This enum is used with open() to describe the mode in which a device is opened. It is also returned by openMode(). \value NotOpen The device is not open. \value ReadOnly The device is open for reading. \value WriteOnly The device is open for writing. \value ReadWrite The device is open for reading and writing. \value Append The device is opened in append mode, so that all data is written to the end of the file. \value Truncate If possible, the device is truncated before it is opened. All earlier contents of the device are lost. \value Text When reading, the end-of-line terminators are translated to '\n'. When writing, the end-of-line terminators are translated to the local encoding, for example '\r\n' for Win32. \value Unbuffered Any buffer in the device is bypassed. Certain flags, such as \c Unbuffered and \c Truncate, are meaningless when used with some subclasses. Some of these restrictions are implied by the type of device that is represented by a subclass; for example, access to a QBuffer is always unbuffered. In other cases, the restriction may be due to the implementation, or may be imposed by the underlying platform; for example, QTcpSocket does not support \c Unbuffered mode, and limitations in the native API prevent QFile from supporting \c Unbuffered on Windows. */ /*! \fn QIODevice::bytesWritten(qint64 bytes) This signal is emitted every time a payload of data has been written to the device. The \a bytes argument is set to the number of bytes that were written in this payload. bytesWritten() is not emitted recursively; if you reenter the event loop or call waitForBytesWritten() inside a slot connected to the bytesWritten() signal, the signal will not be reemitted (although waitForBytesWritten() may still return true). \sa readyRead() */ /*! \fn QIODevice::readyRead() This signal is emitted once every time new data is available for reading from the device. It will only be emitted again once new data is available, such as when a new payload of network data has arrived on your network socket, or when a new block of data has been appended to your device. readyRead() is not emitted recursively; if you reenter the event loop or call waitForReadyRead() inside a slot connected to the readyRead() signal, the signal will not be reemitted (although waitForReadyRead() may still return true). Note for developers implementing classes derived from QIODevice: you should always emit readyRead() when new data has arrived (do not emit it only because there's data still to be read in your buffers). Do not emit readyRead() in other conditions. \sa bytesWritten() */ /*! \fn QIODevice::aboutToClose() This signal is emitted when the device is about to close. Connect this signal if you have operations that need to be performed before the device closes (e.g., if you have data in a separate buffer that needs to be written to the device). */ /*! \fn QIODevice::readChannelFinished() \since 4.4 This signal is emitted when the input (reading) stream is closed in this device. It is emitted as soon as the closing is detected, which means that there might still be data available for reading with read(). \sa atEnd(), read() */ #ifdef QT_NO_QOBJECT QIODevice::QIODevice() : d_ptr(new QIODevicePrivate) { d_ptr->q_ptr = this; } /*! \internal */ QIODevice::QIODevice(QIODevicePrivate &dd) : d_ptr(&dd) { d_ptr->q_ptr = this; } #else /*! Constructs a QIODevice object. */ QIODevice::QIODevice() : QObject(*new QIODevicePrivate, 0) { #if defined QIODEVICE_DEBUG QFile *file = qobject_cast(this); printf("%p QIODevice::QIODevice(\"%s\") %s\n", this, className(), qPrintable(file ? file->fileName() : QString())); #endif } /*! Constructs a QIODevice object with the given \a parent. */ QIODevice::QIODevice(QObject *parent) : QObject(*new QIODevicePrivate, parent) { #if defined QIODEVICE_DEBUG printf("%p QIODevice::QIODevice(%p \"%s\")\n", this, parent, className()); #endif } /*! \internal */ QIODevice::QIODevice(QIODevicePrivate &dd, QObject *parent) : QObject(dd, parent) { } #endif /*! Destructs the QIODevice object. */ QIODevice::~QIODevice() { #if defined QIODEVICE_DEBUG printf("%p QIODevice::~QIODevice()\n", this); #endif } /*! Returns true if this device is sequential; otherwise returns false. Sequential devices, as opposed to a random-access devices, have no concept of a start, an end, a size, or a current position, and they do not support seeking. You can only read from the device when it reports that data is available. The most common example of a sequential device is a network socket. On Unix, special files such as /dev/zero and fifo pipes are sequential. Regular files, on the other hand, do support random access. They have both a size and a current position, and they also support seeking backwards and forwards in the data stream. Regular files are non-sequential. \sa bytesAvailable() */ bool QIODevice::isSequential() const { return false; } /*! Returns the mode in which the device has been opened; i.e. ReadOnly or WriteOnly. \sa OpenMode */ QIODevice::OpenMode QIODevice::openMode() const { return d_func()->openMode; } /*! Sets the OpenMode of the device to \a openMode. Call this function to set the open mode if the flags change after the device has been opened. \sa openMode() OpenMode */ void QIODevice::setOpenMode(OpenMode openMode) { #if defined QIODEVICE_DEBUG printf("%p QIODevice::setOpenMode(0x%x)\n", this, int(openMode)); #endif d_func()->openMode = openMode; d_func()->accessMode = QIODevicePrivate::Unset; } /*! If \a enabled is true, this function sets the \l Text flag on the device; otherwise the \l Text flag is removed. This feature is useful for classes that provide custom end-of-line handling on a QIODevice. \sa open(), setOpenMode() */ void QIODevice::setTextModeEnabled(bool enabled) { Q_D(QIODevice); if (enabled) d->openMode |= Text; else d->openMode &= ~Text; } /*! Returns true if the \l Text flag is enabled; otherwise returns false. \sa setTextModeEnabled() */ bool QIODevice::isTextModeEnabled() const { return d_func()->openMode & Text; } /*! Returns true if the device is open; otherwise returns false. A device is open if it can be read from and/or written to. By default, this function returns false if openMode() returns \c NotOpen. \sa openMode() OpenMode */ bool QIODevice::isOpen() const { return d_func()->openMode != NotOpen; } /*! Returns true if data can be read from the device; otherwise returns false. Use bytesAvailable() to determine how many bytes can be read. This is a convenience function which checks if the OpenMode of the device contains the ReadOnly flag. \sa openMode() OpenMode */ bool QIODevice::isReadable() const { return (openMode() & ReadOnly) != 0; } /*! Returns true if data can be written to the device; otherwise returns false. This is a convenience function which checks if the OpenMode of the device contains the WriteOnly flag. \sa openMode() OpenMode */ bool QIODevice::isWritable() const { return (openMode() & WriteOnly) != 0; } /*! Opens the device and sets its OpenMode to \a mode. Returns true if successful; otherwise returns false. This function should be called from any reimplementations of open() or other functions that open the device. \sa openMode() OpenMode */ bool QIODevice::open(OpenMode mode) { Q_D(QIODevice); d->openMode = mode; d->pos = (mode & Append) ? size() : qint64(0); d->buffer.clear(); d->accessMode = QIODevicePrivate::Unset; #if defined QIODEVICE_DEBUG printf("%p QIODevice::open(0x%x)\n", this, quint32(mode)); #endif return true; } /*! First emits aboutToClose(), then closes the device and sets its OpenMode to NotOpen. The error string is also reset. \sa setOpenMode() OpenMode */ void QIODevice::close() { Q_D(QIODevice); if (d->openMode == NotOpen) return; #if defined QIODEVICE_DEBUG printf("%p QIODevice::close()\n", this); #endif #ifndef QT_NO_QOBJECT emit aboutToClose(); #endif d->openMode = NotOpen; d->errorString.clear(); d->pos = 0; d->buffer.clear(); } /*! For random-access devices, this function returns the position that data is written to or read from. For sequential devices or closed devices, where there is no concept of a "current position", 0 is returned. The current read/write position of the device is maintained internally by QIODevice, so reimplementing this function is not necessary. When subclassing QIODevice, use QIODevice::seek() to notify QIODevice about changes in the device position. \sa isSequential(), seek() */ qint64 QIODevice::pos() const { Q_D(const QIODevice); #if defined QIODEVICE_DEBUG printf("%p QIODevice::pos() == %d\n", this, int(d->pos)); #endif return d->pos; } /*! For open random-access devices, this function returns the size of the device. For open sequential devices, bytesAvailable() is returned. If the device is closed, the size returned will not reflect the actual size of the device. \sa isSequential(), pos() */ qint64 QIODevice::size() const { return d_func()->isSequential() ? bytesAvailable() : qint64(0); } /*! For random-access devices, this function sets the current position to \a pos, returning true on success, or false if an error occurred. For sequential devices, the default behavior is to do nothing and return false. When subclassing QIODevice, you must call QIODevice::seek() at the start of your function to ensure integrity with QIODevice's built-in buffer. The base implementation always returns true. \sa pos(), isSequential() */ bool QIODevice::seek(qint64 pos) { if (d_func()->openMode == NotOpen) { qWarning("QIODevice::seek: The device is not open"); return false; } if (pos < 0) { qWarning("QIODevice::seek: Invalid pos: %d", int(pos)); return false; } Q_D(QIODevice); #if defined QIODEVICE_DEBUG printf("%p QIODevice::seek(%d), before: d->pos = %d, d->buffer.size() = %d\n", this, int(pos), int(d->pos), d->buffer.size()); #endif qint64 offset = pos - d->pos; if (!d->isSequential()) { d->pos = pos; d->devicePos = pos; } if (offset > 0 && !d->buffer.isEmpty()) { // When seeking forwards, we need to pop bytes off the front of the // buffer. do { int bytesToSkip = int(qMin(offset, INT_MAX)); d->buffer.skip(bytesToSkip); offset -= bytesToSkip; } while (offset > 0); } else if (offset < 0) { // When seeking backwards, an operation that is only allowed for // random-access devices, the buffer is cleared. The next read // operation will then refill the buffer. We can optimize this, if we // find that seeking backwards becomes a significant performance hit. d->buffer.clear(); } #if defined QIODEVICE_DEBUG printf("%p \tafter: d->pos == %d, d->buffer.size() == %d\n", this, int(d->pos), d->buffer.size()); #endif return true; } /*! Returns true if the current read and write position is at the end of the device (i.e. there is no more data available for reading on the device); otherwise returns false. For some devices, atEnd() can return true even though there is more data to read. This special case only applies to devices that generate data in direct response to you calling read() (e.g., \c /dev or \c /proc files on Unix and Mac OS X, or console input / \c stdin on all platforms). \sa bytesAvailable(), read(), isSequential() */ bool QIODevice::atEnd() const { Q_D(const QIODevice); #if defined QIODEVICE_DEBUG printf("%p QIODevice::atEnd() returns %s, d->openMode == %d, d->pos == %d\n", this, (d->openMode == NotOpen || d->pos == size()) ? "true" : "false", int(d->openMode), int(d->pos)); #endif return d->openMode == NotOpen || (d->buffer.isEmpty() && bytesAvailable() == 0); } /*! Seeks to the start of input for random-access devices. Returns true on success; otherwise returns false (for example, if the device is not open). Note that when using a QTextStream on a QFile, calling reset() on the QFile will not have the expected result because QTextStream buffers the file. Use the QTextStream::seek() function instead. \sa seek() */ bool QIODevice::reset() { #if defined QIODEVICE_DEBUG printf("%p QIODevice::reset()\n", this); #endif return seek(0); } /*! Returns the number of bytes that are available for reading. This function is commonly used with sequential devices to determine the number of bytes to allocate in a buffer before reading. Subclasses that reimplement this function must call the base implementation in order to include the size of QIODevices' buffer. Example: \snippet doc/src/snippets/code/src_corelib_io_qiodevice.cpp 1 \sa bytesToWrite(), readyRead(), isSequential() */ qint64 QIODevice::bytesAvailable() const { Q_D(const QIODevice); if (!d->isSequential()) return qMax(size() - d->pos, qint64(0)); return d->buffer.size(); } /*! For buffered devices, this function returns the number of bytes waiting to be written. For devices with no buffer, this function returns 0. \sa bytesAvailable(), bytesWritten(), isSequential() */ qint64 QIODevice::bytesToWrite() const { return qint64(0); } /*! Reads at most \a maxSize bytes from the device into \a data, and returns the number of bytes read. If an error occurs, such as when attempting to read from a device opened in WriteOnly mode, this function returns -1. 0 is returned when no more data is available for reading. However, reading past the end of the stream is considered an error, so this function returns -1 in those cases (that is, reading on a closed socket or after a process has died). \sa readData() readLine() write() */ qint64 QIODevice::read(char *data, qint64 maxSize) { Q_D(QIODevice); CHECK_READABLE(read, qint64(-1)); CHECK_MAXLEN(read, qint64(-1)); #if defined QIODEVICE_DEBUG printf("%p QIODevice::read(%p, %d), d->pos = %d, d->buffer.size() = %d\n", this, data, int(maxSize), int(d->pos), int(d->buffer.size())); #endif const bool sequential = d->isSequential(); // Short circuit for getChar() if (maxSize == 1) { int chint = d->buffer.getChar(); if (chint != -1) { char c = char(uchar(chint)); if (c == '\r' && (d->openMode & Text)) { d->buffer.ungetChar(c); } else { if (data) *data = c; if (!sequential) ++d->pos; #if defined QIODEVICE_DEBUG printf("%p \tread 0x%hhx (%c) returning 1 (shortcut)\n", this, int(c), isprint(c) ? c : '?'); #endif return qint64(1); } } } qint64 readSoFar = 0; bool moreToRead = true; do { int lastReadChunkSize = 0; // Try reading from the buffer. if (!d->buffer.isEmpty()) { lastReadChunkSize = d->buffer.read(data + readSoFar, maxSize - readSoFar); readSoFar += lastReadChunkSize; if (!sequential) d->pos += lastReadChunkSize; #if defined QIODEVICE_DEBUG printf("%p \treading %d bytes from buffer into position %d\n", this, lastReadChunkSize, int(readSoFar) - lastReadChunkSize); #endif } else if ((d->openMode & Unbuffered) == 0 && maxSize < QIODEVICE_BUFFERSIZE) { // In buffered mode, we try to fill up the QIODevice buffer before // we do anything else. int bytesToBuffer = qMax(maxSize - readSoFar, QIODEVICE_BUFFERSIZE); char *writePointer = d->buffer.reserve(bytesToBuffer); // Make sure the device is positioned correctly. if (d->pos != d->devicePos && !sequential && !seek(d->pos)) return qint64(-1); qint64 readFromDevice = readData(writePointer, bytesToBuffer); d->buffer.chop(bytesToBuffer - (readFromDevice < 0 ? 0 : int(readFromDevice))); if (readFromDevice > 0) { if (!sequential) d->devicePos += readFromDevice; #if defined QIODEVICE_DEBUG printf("%p \treading %d from device into buffer\n", this, int(readFromDevice)); #endif if (readFromDevice < bytesToBuffer) d->buffer.truncate(readFromDevice < 0 ? 0 : int(readFromDevice)); if (!d->buffer.isEmpty()) { lastReadChunkSize = d->buffer.read(data + readSoFar, maxSize - readSoFar); readSoFar += lastReadChunkSize; if (!sequential) d->pos += lastReadChunkSize; #if defined QIODEVICE_DEBUG printf("%p \treading %d bytes from buffer at position %d\n", this, lastReadChunkSize, int(readSoFar)); #endif } } } // If we need more, try reading from the device. if (readSoFar < maxSize) { // Make sure the device is positioned correctly. if (d->pos != d->devicePos && !sequential && !seek(d->pos)) return qint64(-1); qint64 readFromDevice = readData(data + readSoFar, maxSize - readSoFar); #if defined QIODEVICE_DEBUG printf("%p \treading %d bytes from device (total %d)\n", this, int(readFromDevice), int(readSoFar)); #endif if (readFromDevice == -1 && readSoFar == 0) { // error and we haven't read anything: return immediately return -1; } if (readFromDevice <= 0) { moreToRead = false; } else { // see if we read as much data as we asked for if (readFromDevice < maxSize - readSoFar) moreToRead = false; lastReadChunkSize += int(readFromDevice); readSoFar += readFromDevice; if (!sequential) { d->pos += readFromDevice; d->devicePos += readFromDevice; } } } else { moreToRead = false; } if (readSoFar && d->openMode & Text) { char *readPtr = data + readSoFar - lastReadChunkSize; const char *endPtr = data + readSoFar; if (readPtr < endPtr) { // optimization to avoid initial self-assignment while (*readPtr != '\r') { if (++readPtr == endPtr) return readSoFar; } char *writePtr = readPtr; while (readPtr < endPtr) { char ch = *readPtr++; if (ch != '\r') *writePtr++ = ch; else --readSoFar; } // Make sure we get more data if there is room for more. This // is very important for when someone seeks to the start of a // '\r\n' and reads one character - they should get the '\n'. moreToRead = (readPtr != writePtr); } } } while (moreToRead); #if defined QIODEVICE_DEBUG printf("%p \treturning %d, d->pos == %d, d->buffer.size() == %d\n", this, int(readSoFar), int(d->pos), d->buffer.size()); debugBinaryString(data, readSoFar); #endif return readSoFar; } /*! \overload Reads at most \a maxSize bytes from the device, and returns the data read as a QByteArray. This function has no way of reporting errors; returning an empty QByteArray() can mean either that no data was currently available for reading, or that an error occurred. */ QByteArray QIODevice::read(qint64 maxSize) { Q_D(QIODevice); CHECK_MAXLEN(read, QByteArray()); QByteArray tmp; qint64 readSoFar = 0; char buffer[4096]; #if defined QIODEVICE_DEBUG printf("%p QIODevice::read(%d), d->pos = %d, d->buffer.size() = %d\n", this, int(maxSize), int(d->pos), int(d->buffer.size())); #else Q_UNUSED(d); #endif do { qint64 bytesToRead = qMin(int(maxSize - readSoFar), int(sizeof(buffer))); qint64 readBytes = read(buffer, bytesToRead); if (readBytes <= 0) break; tmp.append(buffer, (int) readBytes); readSoFar += readBytes; } while (readSoFar < maxSize && bytesAvailable() > 0); return tmp; } /*! \overload Reads all available data from the device, and returns it as a QByteArray. This function has no way of reporting errors; returning an empty QByteArray() can mean either that no data was currently available for reading, or that an error occurred. */ QByteArray QIODevice::readAll() { Q_D(QIODevice); #if defined QIODEVICE_DEBUG printf("%p QIODevice::readAll(), d->pos = %d, d->buffer.size() = %d\n", this, int(d->pos), int(d->buffer.size())); #endif QByteArray tmp; if (d->isSequential() || size() == 0) { // Read it in chunks. Use bytesAvailable() as an unreliable hint for // sequential devices, but try to read 4K as a minimum. int chunkSize = qMax(qint64(4096), bytesAvailable()); qint64 totalRead = 0; forever { tmp.resize(tmp.size() + chunkSize); qint64 readBytes = read(tmp.data() + totalRead, chunkSize); tmp.chop(chunkSize - (readBytes < 0 ? 0 : readBytes)); if (readBytes <= 0) return tmp; totalRead += readBytes; chunkSize = qMax(qint64(4096), bytesAvailable()); } } else { // Read it all in one go. tmp.resize(int(bytesAvailable())); qint64 readBytes = read(tmp.data(), tmp.size()); tmp.resize(readBytes < 0 ? 0 : int(readBytes)); } return tmp; } /*! This function reads a line of ASCII characters from the device, up to a maximum of \a maxSize - 1 bytes, stores the characters in \a data, and returns the number of bytes read. If a line could not be read but no error ocurred, this function returns 0. If an error occurs, this function returns what it could the length of what could be read, or -1 if nothing was read. A terminating '\0' byte is always appended to \a data, so \a maxSize must be larger than 1. Data is read until either of the following conditions are met: \list \o The first '\n' character is read. \o \a maxSize - 1 bytes are read. \o The end of the device data is detected. \endlist For example, the following code reads a line of characters from a file: \snippet doc/src/snippets/code/src_corelib_io_qiodevice.cpp 2 The newline character ('\n') is included in the buffer. If a newline is not encountered before maxSize - 1 bytes are read, a newline will not be inserted into the buffer. On windows newline characters are replaced with '\n'. This function calls readLineData(), which is implemented using repeated calls to getChar(). You can provide a more efficient implementation by reimplementing readLineData() in your own subclass. \sa getChar(), read(), write() */ qint64 QIODevice::readLine(char *data, qint64 maxSize) { Q_D(QIODevice); if (maxSize < 2) { qWarning("QIODevice::readLine: Called with maxSize < 2"); return qint64(-1); } #if defined QIODEVICE_DEBUG printf("%p QIODevice::readLine(%p, %d), d->pos = %d, d->buffer.size() = %d\n", this, data, int(maxSize), int(d->pos), int(d->buffer.size())); #endif // Leave room for a '\0' --maxSize; const bool sequential = d->isSequential(); qint64 readSoFar = 0; if (!d->buffer.isEmpty()) { readSoFar = d->buffer.readLine(data, maxSize); if (!sequential) d->pos += readSoFar; #if defined QIODEVICE_DEBUG printf("%p \tread from buffer: %d bytes, last character read: %hhx\n", this, int(readSoFar), data[int(readSoFar) - 1]); if (readSoFar) debugBinaryString(data, int(readSoFar)); #endif if (readSoFar && data[readSoFar - 1] == '\n') { if (d->openMode & Text) { // QRingBuffer::readLine() isn't Text aware. if (readSoFar > 1 && data[readSoFar - 2] == '\r') { --readSoFar; data[readSoFar - 1] = '\n'; } } data[readSoFar] = '\0'; return readSoFar; } } if (d->pos != d->devicePos && !sequential && !seek(d->pos)) return qint64(-1); d->baseReadLineDataCalled = false; qint64 readBytes = readLineData(data + readSoFar, maxSize - readSoFar); #if defined QIODEVICE_DEBUG printf("%p \tread from readLineData: %d bytes, readSoFar = %d bytes\n", this, int(readBytes), int(readSoFar)); if (readBytes > 0) { debugBinaryString(data, int(readSoFar + readBytes)); } #endif if (readBytes < 0) { data[readSoFar] = '\0'; return readSoFar ? readSoFar : -1; } readSoFar += readBytes; if (!d->baseReadLineDataCalled && !sequential) { d->pos += readBytes; // If the base implementation was not called, then we must // assume the device position is invalid and force a seek. d->devicePos = qint64(-1); } data[readSoFar] = '\0'; if (d->openMode & Text) { if (readSoFar > 1 && data[readSoFar - 1] == '\n' && data[readSoFar - 2] == '\r') { data[readSoFar - 2] = '\n'; data[readSoFar - 1] = '\0'; --readSoFar; } } #if defined QIODEVICE_DEBUG printf("%p \treturning %d, d->pos = %d, d->buffer.size() = %d, size() = %d\n", this, int(readSoFar), int(d->pos), d->buffer.size(), int(size())); debugBinaryString(data, int(readSoFar)); #endif return readSoFar; } /*! \overload Reads a line from the device, but no more than \a maxSize characters, and returns the result as a QByteArray. This function has no way of reporting errors; returning an empty QByteArray() can mean either that no data was currently available for reading, or that an error occurred. */ QByteArray QIODevice::readLine(qint64 maxSize) { Q_D(QIODevice); CHECK_MAXLEN(readLine, QByteArray()); QByteArray tmp; const int BufferGrowth = 4096; qint64 readSoFar = 0; qint64 readBytes = 0; #if defined QIODEVICE_DEBUG printf("%p QIODevice::readLine(%d), d->pos = %d, d->buffer.size() = %d\n", this, int(maxSize), int(d->pos), int(d->buffer.size())); #else Q_UNUSED(d); #endif do { if (maxSize != 0) tmp.resize(int(readSoFar + qMin(int(maxSize), BufferGrowth))); else tmp.resize(int(readSoFar + BufferGrowth)); readBytes = readLine(tmp.data() + readSoFar, tmp.size() - readSoFar); if (readBytes <= 0) break; readSoFar += readBytes; } while ((!maxSize || readSoFar < maxSize) && readSoFar + 1 == tmp.size() && // +1 due to the ending null tmp.at(readSoFar - 1) != '\n'); if (readSoFar == 0 && readBytes == -1) tmp.clear(); // return Null if we found an error else tmp.resize(int(readSoFar)); return tmp; } /*! Reads up to \a maxSize characters into \a data and returns the number of characters read. This function is called by readLine(), and provides its base implementation, using getChar(). Buffered devices can improve the performance of readLine() by reimplementing this function. readLine() appends a '\0' byte to \a data; readLineData() does not need to do this. If you reimplement this function, be careful to return the correct value: it should return the number of bytes read in this line, including the terminating newline, or 0 if there is no line to be read at this point. If an error occurs, it should return -1 if and only if no bytes were read. Reading past EOF is considered an error. */ qint64 QIODevice::readLineData(char *data, qint64 maxSize) { Q_D(QIODevice); qint64 readSoFar = 0; char c; int lastReadReturn = 0; d->baseReadLineDataCalled = true; while (readSoFar < maxSize && (lastReadReturn = read(&c, 1)) == 1) { *data++ = c; ++readSoFar; if (c == '\n') break; } #if defined QIODEVICE_DEBUG printf("%p QIODevice::readLineData(%p, %d), d->pos = %d, d->buffer.size() = %d, returns %d\n", this, data, int(maxSize), int(d->pos), int(d->buffer.size()), int(readSoFar)); #endif if (lastReadReturn != 1 && readSoFar == 0) return isSequential() ? lastReadReturn : -1; return readSoFar; } /*! Returns true if a complete line of data can be read from the device; otherwise returns false. Note that unbuffered devices, which have no way of determining what can be read, always return false. This function is often called in conjunction with the readyRead() signal. Subclasses that reimplement this function must call the base implementation in order to include the contents of the QIODevice's buffer. Example: \snippet doc/src/snippets/code/src_corelib_io_qiodevice.cpp 3 \sa readyRead(), readLine() */ bool QIODevice::canReadLine() const { return d_func()->buffer.canReadLine(); } /*! Writes at most \a maxSize bytes of data from \a data to the device. Returns the number of bytes that were actually written, or -1 if an error occurred. \sa read() writeData() */ qint64 QIODevice::write(const char *data, qint64 maxSize) { Q_D(QIODevice); CHECK_WRITABLE(write, qint64(-1)); CHECK_MAXLEN(write, qint64(-1)); const bool sequential = d->isSequential(); // Make sure the device is positioned correctly. if (d->pos != d->devicePos && !sequential && !seek(d->pos)) return qint64(-1); #ifdef Q_OS_WIN if (d->openMode & Text) { const char *endOfData = data + maxSize; const char *startOfBlock = data; qint64 writtenSoFar = 0; forever { const char *endOfBlock = startOfBlock; while (endOfBlock < endOfData && *endOfBlock != '\n') ++endOfBlock; qint64 blockSize = endOfBlock - startOfBlock; if (blockSize > 0) { qint64 ret = writeData(startOfBlock, blockSize); if (ret <= 0) { if (writtenSoFar && !sequential) d->buffer.skip(writtenSoFar); return writtenSoFar ? writtenSoFar : ret; } if (!sequential) { d->pos += ret; d->devicePos += ret; } writtenSoFar += ret; } if (endOfBlock == endOfData) break; qint64 ret = writeData("\r\n", 2); if (ret <= 0) { if (writtenSoFar && !sequential) d->buffer.skip(writtenSoFar); return writtenSoFar ? writtenSoFar : ret; } if (!sequential) { d->pos += ret; d->devicePos += ret; } ++writtenSoFar; startOfBlock = endOfBlock + 1; } if (writtenSoFar && !sequential) d->buffer.skip(writtenSoFar); return writtenSoFar; } #endif qint64 written = writeData(data, maxSize); if (written > 0) { if (!sequential) { d->pos += written; d->devicePos += written; } if (!d->buffer.isEmpty() && !sequential) d->buffer.skip(written); } return written; } /*! \since 4.5 \overload Writes data from a zero-terminated string of 8-bit characters to the device. Returns the number of bytes that were actually written, or -1 if an error occurred. This is equivalent to \code ... QIODevice::write(data, qstrlen(data)); ... \endcode \sa read() writeData() */ qint64 QIODevice::write(const char *data) { return write(data, qstrlen(data)); } /*! \fn qint64 QIODevice::write(const QByteArray &byteArray) \overload Writes the content of \a byteArray to the device. Returns the number of bytes that were actually written, or -1 if an error occurred. \sa read() writeData() */ /*! Puts the character \a c back into the device, and decrements the current position unless the position is 0. This function is usually called to "undo" a getChar() operation, such as when writing a backtracking parser. If \a c was not previously read from the device, the behavior is undefined. */ void QIODevice::ungetChar(char c) { Q_D(QIODevice); CHECK_READABLE(read, Q_VOID); #if defined QIODEVICE_DEBUG printf("%p QIODevice::ungetChar(0x%hhx '%c')\n", this, c, isprint(c) ? c : '?'); #endif d->buffer.ungetChar(c); if (!d->isSequential()) --d->pos; } /*! \fn bool QIODevice::putChar(char c) Writes the character \a c to the device. Returns true on success; otherwise returns false. \sa write() getChar() ungetChar() */ bool QIODevice::putChar(char c) { return d_func()->putCharHelper(c); } /*! \internal */ bool QIODevicePrivate::putCharHelper(char c) { return q_func()->write(&c, 1) == 1; } /*! \fn bool QIODevice::getChar(char *c) Reads one character from the device and stores it in \a c. If \a c is 0, the character is discarded. Returns true on success; otherwise returns false. \sa read() putChar() ungetChar() */ bool QIODevice::getChar(char *c) { Q_D(QIODevice); const OpenMode openMode = d->openMode; if (!(openMode & ReadOnly)) { if (openMode == NotOpen) qWarning("QIODevice::getChar: Closed device"); else qWarning("QIODevice::getChar: WriteOnly device"); return false; } // Shortcut for QIODevice::read(c, 1) QRingBuffer *buffer = &d->buffer; const int chint = buffer->getChar(); if (chint != -1) { char ch = char(uchar(chint)); if ((openMode & Text) && ch == '\r') { buffer->ungetChar(ch); } else { if (c) *c = ch; if (!d->isSequential()) ++d->pos; return true; } } // Fall back to read(). char ch; if (read(&ch, 1) == 1) { if (c) *c = ch; return true; } return false; } /*! \since 4.1 Reads at most \a maxSize bytes from the device into \a data, without side effects (i.e., if you call read() after peek(), you will get the same data). Returns the number of bytes read. If an error occurs, such as when attempting to peek a device opened in WriteOnly mode, this function returns -1. 0 is returned when no more data is available for reading. Example: \snippet doc/src/snippets/code/src_corelib_io_qiodevice.cpp 4 \sa read() */ qint64 QIODevice::peek(char *data, qint64 maxSize) { qint64 readBytes = read(data, maxSize); int i = readBytes; while (i > 0) ungetChar(data[i-- - 1]); return readBytes; } /*! \since 4.1 \overload Peeks at most \a maxSize bytes from the device, returning the data peeked as a QByteArray. Example: \snippet doc/src/snippets/code/src_corelib_io_qiodevice.cpp 5 This function has no way of reporting errors; returning an empty QByteArray() can mean either that no data was currently available for peeking, or that an error occurred. \sa read() */ QByteArray QIODevice::peek(qint64 maxSize) { QByteArray result = read(maxSize); int i = result.size(); const char *data = result.constData(); while (i > 0) ungetChar(data[i-- - 1]); return result; } /*! Blocks until data is available for reading and the readyRead() signal has been emitted, or until \a msecs milliseconds have passed. If msecs is -1, this function will not time out. Returns true if data is available for reading; otherwise returns false (if the operation timed out or if an error occurred). This function can operate without an event loop. It is useful when writing non-GUI applications and when performing I/O operations in a non-GUI thread. If called from within a slot connected to the readyRead() signal, readyRead() will not be reemitted. Reimplement this function to provide a blocking API for a custom device. The default implementation does nothing, and returns false. \warning Calling this function from the main (GUI) thread might cause your user interface to freeze. \sa waitForBytesWritten() */ bool QIODevice::waitForReadyRead(int msecs) { Q_UNUSED(msecs); return false; } /*! For buffered devices, this function waits until a payload of buffered written data has been written to the device and the bytesWritten() signal has been emitted, or until \a msecs milliseconds have passed. If msecs is -1, this function will not time out. For unbuffered devices, it returns immediately. Returns true if a payload of data was written to the device; otherwise returns false (i.e. if the operation timed out, or if an error occurred). This function can operate without an event loop. It is useful when writing non-GUI applications and when performing I/O operations in a non-GUI thread. If called from within a slot connected to the bytesWritten() signal, bytesWritten() will not be reemitted. Reimplement this function to provide a blocking API for a custom device. The default implementation does nothing, and returns false. \warning Calling this function from the main (GUI) thread might cause your user interface to freeze. \sa waitForReadyRead() */ bool QIODevice::waitForBytesWritten(int msecs) { Q_UNUSED(msecs); return false; } /*! Sets the human readable description of the last device error that occurred to \a str. \sa errorString() */ void QIODevice::setErrorString(const QString &str) { d_func()->errorString = str; } /*! Returns a human-readable description of the last device error that occurred. \sa setErrorString() */ QString QIODevice::errorString() const { Q_D(const QIODevice); if (d->errorString.isEmpty()) { #ifdef QT_NO_QOBJECT return QLatin1String(QT_TRANSLATE_NOOP(QIODevice, "Unknown error")); #else return tr("Unknown error"); #endif } return d->errorString; } /*! \fn qint64 QIODevice::readData(char *data, qint64 maxSize) Reads up to \a maxSize bytes from the device into \a data, and returns the number of bytes read or -1 if an error occurred. If there are no bytes to be read, this function should return -1 if there can never be more bytes available (for example: socket closed, pipe closed, sub-process finished). This function is called by QIODevice. Reimplement this function when creating a subclass of QIODevice. \sa read() readLine() writeData() */ /*! \fn qint64 QIODevice::writeData(const char *data, qint64 maxSize) Writes up to \a maxSize bytes from \a data to the device. Returns the number of bytes written, or -1 if an error occurred. This function is called by QIODevice. Reimplement this function when creating a subclass of QIODevice. \sa read() write() */ /*! \fn QIODevice::Offset QIODevice::status() const For device specific error handling, please refer to the individual device documentation. \sa qobject_cast() */ /*! \fn QIODevice::Offset QIODevice::at() const Use pos() instead. */ /*! \fn bool QIODevice::at(Offset offset) Use seek(\a offset) instead. */ /*! \fn int QIODevice::flags() const Use openMode() instead. */ /*! \fn int QIODevice::getch() Use getChar() instead. */ /*! \fn bool QIODevice::isAsynchronous() const This functionality is no longer available. This function always returns true. */ /*! \fn bool QIODevice::isBuffered() const Use !(openMode() & QIODevice::Unbuffered) instead. */ /*! \fn bool QIODevice::isCombinedAccess() const Use openMode() instead. */ /*! \fn bool QIODevice::isDirectAccess() const Use !isSequential() instead. */ /*! \fn bool QIODevice::isInactive() const Use isOpen(), isReadable(), or isWritable() instead. */ /*! \fn bool QIODevice::isRaw() const Use openMode() instead. */ /*! \fn bool QIODevice::isSequentialAccess() const Use isSequential() instead. */ /*! \fn bool QIODevice::isSynchronous() const This functionality is no longer available. This function always returns false. */ /*! \fn bool QIODevice::isTranslated() const Use openMode() instead. */ /*! \fn bool QIODevice::mode() const Use openMode() instead. */ /*! \fn int QIODevice::putch(int ch) Use putChar(\a ch) instead. */ /*! \fn int QIODevice::ungetch(int ch) Use ungetChar(\a ch) instead. */ /*! \fn quint64 QIODevice::readBlock(char *data, quint64 size) Use read(\a data, \a size) instead. */ /*! \fn int QIODevice::state() const Use isOpen() instead. */ /*! \fn qint64 QIODevice::writeBlock(const char *data, quint64 size) Use write(\a data, \a size) instead. */ /*! \fn qint64 QIODevice::writeBlock(const QByteArray &data) Use write(\a data) instead. */ #if defined QT3_SUPPORT QIODevice::Status QIODevice::status() const { #if !defined(QT_NO_QOBJECT) const QFile *f = qobject_cast(this); if (f) return (int) f->error(); #endif return isOpen() ? 0 /* IO_Ok */ : 8 /* IO_UnspecifiedError */; } /*! For device specific error handling, please refer to the individual device documentation. \sa qobject_cast() */ void QIODevice::resetStatus() { #if !defined(QT_NO_QOBJECT) QFile *f = qobject_cast(this); if (f) f->unsetError(); #endif } #endif #if !defined(QT_NO_DEBUG_STREAM) QDebug operator<<(QDebug debug, QIODevice::OpenMode modes) { debug << "OpenMode("; QStringList modeList; if (modes == QIODevice::NotOpen) { modeList << QLatin1String("NotOpen"); } else { if (modes & QIODevice::ReadOnly) modeList << QLatin1String("ReadOnly"); if (modes & QIODevice::WriteOnly) modeList << QLatin1String("WriteOnly"); if (modes & QIODevice::Append) modeList << QLatin1String("Append"); if (modes & QIODevice::Truncate) modeList << QLatin1String("Truncate"); if (modes & QIODevice::Text) modeList << QLatin1String("Text"); if (modes & QIODevice::Unbuffered) modeList << QLatin1String("Unbuffered"); } qSort(modeList); debug << modeList.join(QLatin1String("|")); debug << ")"; return debug; } #endif QT_END_NAMESPACE