#include <KAutoSaveFile>

Inheritance diagram for KAutoSaveFile:

Public Member Functions
	KAutoSaveFile (const KUrl &filename, QObject *parent=0)

	KAutoSaveFile (QObject *parent=0)

	~KAutoSaveFile ()

KUrl	managedFile () const

virtual bool	open (OpenMode openmode)

virtual void	releaseLock ()

void	setManagedFile (const KUrl &filename)

Public Member Functions inherited from QFile
	QFile (const QString &name)

	QFile (QObject *parent)

	QFile (const QString &name, QObject *parent)

	~QFile ()

virtual bool	atEnd () const

virtual void	close ()

bool	copy (const QString &newName)

FileError	error () const

bool	exists () const

QString	fileName () const

bool	flush ()

int	handle () const

virtual bool	isSequential () const

bool	link (const QString &linkName)

uchar *	map (qint64 offset, qint64 size, MemoryMapFlags flags)

QString	name () const

bool	open (QFlags< QIODevice::OpenModeFlag > aFlags, int fd)

bool	open (FILE *fh, QFlags< QIODevice::OpenModeFlag > mode)

bool	open (int fd, QFlags< QIODevice::OpenModeFlag > mode)

bool	open (const RFile &f, QFlags< QIODevice::OpenModeFlag > mode, QFlags< QFile::FileHandleFlag > handleFlags)

bool	open (FILE *fh, QFlags< QIODevice::OpenModeFlag > mode, QFlags< QFile::FileHandleFlag > handleFlags)

bool	open (int fd, QFlags< QIODevice::OpenModeFlag > mode, QFlags< QFile::FileHandleFlag > handleFlags)

bool	open (QFlags< QIODevice::OpenModeFlag > aFlags, FILE *f)

virtual bool	open (QFlags< QIODevice::OpenModeFlag > mode)

Permissions	permissions () const

virtual qint64	pos () const

QString	readLink () const

bool	remove ()

bool	rename (const QString &newName)

bool	resize (qint64 sz)

virtual bool	seek (qint64 pos)

void	setFileName (const QString &name)

void	setName (const QString &name)

bool	setPermissions (QFlags< QFile::Permission > permissions)

virtual qint64	size () const

QString	symLinkTarget () const

bool	unmap (uchar *address)

void	unsetError ()

Public Member Functions inherited from QIODevice
	QIODevice ()

	QIODevice (QObject *parent)

virtual	~QIODevice ()

void	aboutToClose ()

Offset	at () const

bool	at (Offset offset)

virtual qint64	bytesAvailable () const

virtual qint64	bytesToWrite () const

void	bytesWritten (qint64 bytes)

virtual bool	canReadLine () const

QString	errorString () const

int	flags () const

int	getch ()

bool	getChar (char *c)

bool	isAsynchronous () const

bool	isBuffered () const

bool	isCombinedAccess () const

bool	isDirectAccess () const

bool	isInactive () const

bool	isOpen () const

bool	isRaw () const

bool	isReadable () const

bool	isSequentialAccess () const

bool	isSynchronous () const

bool	isTextModeEnabled () const

bool	isTranslated () const

bool	isWritable () const

int	mode () const

OpenMode	openMode () const

qint64	peek (char *data, qint64 maxSize)

QByteArray	peek (qint64 maxSize)

int	putch (int ch)

bool	putChar (char c)

qint64	read (char *data, qint64 maxSize)

QByteArray	read (qint64 maxSize)

QByteArray	readAll ()

qint64	readBlock (char *data, quint64 size)

void	readChannelFinished ()

QByteArray	readLine (qint64 maxSize)

qint64	readLine (char *data, qint64 maxSize)

void	readyRead ()

virtual bool	reset ()

void	resetStatus ()

void	setTextModeEnabled (bool enabled)

int	state () const

Status	status () const

int	ungetch (int ch)

void	ungetChar (char c)

virtual bool	waitForBytesWritten (int msecs)

virtual bool	waitForReadyRead (int msecs)

qint64	write (const char *data)

qint64	write (const char *data, qint64 maxSize)

qint64	write (const QByteArray &byteArray)

qint64	writeBlock (const QByteArray &data)

qint64	writeBlock (const char *data, quint64 size)

Public Member Functions inherited from QObject
	QObject (QObject *parent)

	QObject (QObject parent, const char name)

virtual	~QObject ()

bool	blockSignals (bool block)

QObject *	child (const char objName, const char inheritsClass, bool recursiveSearch) const

const QObjectList &	children () const

const char *	className () const

bool	connect (const QObject sender, const char signal, const char *method, Qt::ConnectionType type) const

void	deleteLater ()

void	destroyed (QObject *obj)

bool	disconnect (const QObject receiver, const char method)

bool	disconnect (const char signal, const QObject receiver, const char *method)

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QByteArray >	dynamicPropertyNames () const

virtual bool	event (QEvent *e)

virtual bool	eventFilter (QObject watched, QEvent event)

T	findChild (const QString &name) const

QList< T >	findChildren (const QRegExp &regExp) const

QList< T >	findChildren (const QString &name) const

bool	inherits (const char *className) const

void	insertChild (QObject *object)

void	installEventFilter (QObject *filterObj)

bool	isA (const char *className) const

bool	isWidgetType () const

void	killTimer (int id)

virtual const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

const char *	name () const

const char *	name (const char *defaultName) const

QString	objectName () const

QObject *	parent () const

QVariant	property (const char *name) const

void	removeChild (QObject *object)

void	removeEventFilter (QObject *obj)

void	setName (const char *name)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const char *name, const QVariant &value)

bool	signalsBlocked () const

int	startTimer (int interval)

QThread *	thread () const

Static Public Member Functions
static QList< KAutoSaveFile * >	allStaleFiles (const QString &applicationName=QString())

static QList< KAutoSaveFile * >	staleFiles (const KUrl &filename, const QString &applicationName=QString())

Static Public Member Functions inherited from QFile
bool	copy (const QString &fileName, const QString &newName)

QString	decodeName (const QByteArray &localFileName)

QString	decodeName (const char *localFileName)

QByteArray	encodeName (const QString &fileName)

bool	exists (const QString &fileName)

bool	link (const QString &fileName, const QString &linkName)

Permissions	permissions (const QString &fileName)

QString	readLink (const QString &fileName)

bool	remove (const QString &fileName)

bool	rename (const QString &oldName, const QString &newName)

bool	resize (const QString &fileName, qint64 sz)

void	setDecodingFunction (DecoderFn function)

void	setEncodingFunction (EncoderFn function)

bool	setPermissions (const QString &fileName, QFlags< QFile::Permission > permissions)

QString	symLinkTarget (const QString &fileName)

Static Public Member Functions inherited from QObject
bool	connect (const QObject sender, const char signal, const QObject receiver, const char method, Qt::ConnectionType type)

bool	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type)

bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char method)

bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method)

QString	tr (const char sourceText, const char disambiguation, int n)

QString	trUtf8 (const char sourceText, const char disambiguation, int n)

Additional Inherited Members
Public Attributes inherited from QFile
typedef	DecoderFn

typedef	EncoderFn

typedef	FileHandleFlags

typedef	Permissions

typedef	PermissionSpec

Public Attributes inherited from QIODevice
typedef	Offset

typedef	OpenMode

typedef	Status

Protected Member Functions inherited from QFile
virtual qint64	readData (char *data, qint64 len)

virtual qint64	readLineData (char *data, qint64 maxlen)

virtual qint64	writeData (const char *data, qint64 len)

Protected Member Functions inherited from QIODevice
virtual qint64	readData (char *data, qint64 maxSize)=0

void	setErrorString (const QString &str)

void	setOpenMode (QFlags< QIODevice::OpenModeFlag > openMode)

virtual qint64	writeData (const char *data, qint64 maxSize)=0

Protected Member Functions inherited from QObject
bool	checkConnectArgs (const char signal, const QObject object, const char *method)

virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const char *signal)

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const char *signal)

int	receivers (const char *signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Static Protected Member Functions inherited from QObject
QByteArray	normalizeSignalSlot (const char *signalSlot)

Properties inherited from QObject
	objectName

Detailed Description

Creates and manages a temporary "auto-save" file.

Autosave files are temporary files that applications use to store the unsaved data in a file they have open for editing. KAutoSaveFile allows you to easily create and manage such files, as well as to recover the unsaved data left over by a crashed or otherwise gone process.

Each KAutoSaveFile object is associated with one specific file that the application holds open. KAutoSaveFile is also a QObject, so it can be reparented to the actual opened file object, so as to manage the lifetime of the temporary file.

Typical use consists of:

verifying whether stale autosave files exist for the opened file
deciding whether to recover the old, autosaved data
if not recovering, creating a KAutoSaveFile object for the opened file
during normal execution of the program, periodically save unsaved data into the KAutoSaveFile file.

KAutoSaveFile holds a lock on the autosave file, so it's safe to delete the file and recreate it later. Because of that, disposing of stale autosave files should be done with releaseLock(). No lock is held on the managed file.

Examples: Opening a new file:

void Document::open(const KUrl &url)
{
    // check whether autosave files exist:
    QList<KAutoSaveFile *> staleFiles = KAutoSaveFile::staleFiles(url);
    if (!staleFiles.isEmpty()) {
        if (KMessageBox::questionYesNo(parent,
                                       "Auto-saved files exist. Do you want to recover them now?",
                                       "File Recovery",
                                       "Recover", "Don't recover") == KMessage::Yes) {
            recoverFiles(staleFiles);
            return;
        } else {
            // remove the stale files
            foreach (KAutoSaveFile *stale, staleFiles) {
                stale->open(QIODevice::ReadWrite);
                delete stale;
            }
        }
    }
    // create new autosave object
    m_autosave = new KAutoSaveFile(url, this);
    // continue the process of opening file 'url'
    ...
}

The function recoverFiles could loop over the list of files and do this:

foreach (KAutoSaveFile *stale, staleFiles) {
    if (!stale->open(QIODevice::ReadWrite)) {
        // show an error message; we could not steal the lockfile
        // maybe another application got to the file before us?
        delete stale;
        continue;
    }
    Document *doc = new Document;
    doc->m_autosave = stale;
    stale->setParent(doc); // reparent
    doc->setUrl(stale->managedFile());
    doc->setContents(stale->readAll());
    doc->setState(Document::Modified); // mark it as modified and unsaved
    documentManager->addDocument(doc);
}

If the file is unsaved, periodically write the contents to the save file:

if (!m_autosave->isOpen() && !m_autosave->open(QIODevice::ReadWrite)) {
    // show error: could not open the autosave file
}
m_autosave->write(contents());

When the user saves the file, the autosaved file is no longer necessary and can be removed or emptied.

m_autosave->resize(0); // leaves the file open

m_autosave->remove(); // closes the file

Author: Jacob R Rideout kde@j.nosp@m.acob.nosp@m.rideo.nosp@m.ut.n.nosp@m.et

Definition at line 129 of file kautosavefile.h.

Constructor & Destructor Documentation

KAutoSaveFile::KAutoSaveFile	(	const KUrl &	filename,
		QObject *	parent = `0`
	)

explicit

Constructs a KAutoSaveFile for file filename.

The temporary file is not opened or created until actually needed. The file filename does not have to exist for KAutoSaveFile to be constructed (if it exists, it will not be touched).

Parameters

filename	the filename that this KAutoSaveFile refers to
parent	the parent object

Definition at line 71 of file kautosavefile.cpp.

KAutoSaveFile::KAutoSaveFile ( QObject * parent = 0 )

explicit

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Constructs a KAutoSaveFile object.

Note that you need to call setManagedFile() before calling open().

Parameters

parent the parent object

Definition at line 79 of file kautosavefile.cpp.

KAutoSaveFile::~KAutoSaveFile ( )

Destroys the KAutoSaveFile object, removes the autosave file and drops the lock being held (if any).

Definition at line 86 of file kautosavefile.cpp.

Member Function Documentation

QList< KAutoSaveFile * > KAutoSaveFile::allStaleFiles ( const QString & applicationName = QString() )

static

Returns all stale autosave files left behind by crashed or otherwise gone instances of this application.

If not given, the application name is obtained from QCoreApplication, so be sure to have set it correctly before calling this function.

See staleFiles() for information on the returned objects.

Definition at line 190 of file kautosavefile.cpp.

KUrl KAutoSaveFile::managedFile ( ) const

Retrieves the URL of the file managed by KAutoSaveFile.

This is the same URL that was given to setManagedFile() or the KAutoSaveFile constructor.

This is the name of the real file being edited by the application. To get the name of the temporary file where data can be saved, use fileName() (after you have called open()).

Definition at line 92 of file kautosavefile.cpp.

bool KAutoSaveFile::open ( OpenMode openmode )

virtual

Opens the autosave file and locks it if it wasn't already locked.

The name of the temporary file where data can be saved to will be set by this function and can be retrieved with fileName(). It will not change unless releaseLock() is called. No other application will attempt to edit such a file either while the lock is held.

Parameters

openmode the mode that should be used to open the file, probably QIODevice::ReadWrite

Returns: true if the file could be opened (= locked and created), false if the operation failed

Definition at line 115 of file kautosavefile.cpp.

void KAutoSaveFile::releaseLock ( )

virtual

Closes the autosave file resource and removes the lock file.

The file name returned by fileName() will no longer be protected and can be overwritten by another application at any time. To obtain a new lock, call open() again.

This function calls remove(), so the autosave temporary file will be removed too.

Definition at line 105 of file kautosavefile.cpp.

void KAutoSaveFile::setManagedFile ( const KUrl & filename )

Sets the URL of the file managed by KAutoSaveFile.

This should be the name of the real file being edited by the application. If the file was previously set, this function calls releaseLock().

Parameters

filename the filename that this KAutoSaveFile refers to

Definition at line 97 of file kautosavefile.cpp.

QList< KAutoSaveFile * > KAutoSaveFile::staleFiles	(	const KUrl &	filename,
		const QString &	applicationName = `QString()`
	)

static

Checks for stale autosave files for filename.

Returns a list of autosave files that contain autosaved data left behind by other instances of the application, due to crashing or otherwise uncleanly exiting.

It is the application's job to determine what to do with such unsaved data. Generally, this is done by asking the user if he wants to see the recovered data, and then allowing the user to save if he wants to.

If not given, the application name is obtained from QCoreApplication, so be sure to have set it correctly before calling this function.

This function returns a list of unopened KAutoSaveFile objects. By calling open() on them, the application will steal the lock. Subsequent releaseLock() or deleting of the object will then erase the stale autosave file.

Definition at line 151 of file kautosavefile.cpp.

The documentation for this class was generated from the following files:

KDECore

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

KDECore

kdelibs API Reference

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