KAutoSaveFile

Search for usage in LXR

#include <KAutoSaveFile>

Inheritance diagram for KAutoSaveFile:

Public Member Functions

 KAutoSaveFile (const QUrl &filename, QObject *parent=nullptr)
 
 KAutoSaveFile (QObject *parent=nullptr)
 
 ~KAutoSaveFile () override
 
QUrl managedFile () const
 
bool open (OpenMode openmode) override
 
virtual void releaseLock ()
 
void setManagedFile (const QUrl &filename)
 
- Public Member Functions inherited from QFile
 QFile (const QString &name)
 
 QFile (const QString &name, QObject *parent)
 
 QFile (const std::filesystem::path &name)
 
 QFile (const std::filesystem::path &name, QObject *parent)
 
 QFile (QObject *parent)
 
bool copy (const QString &newName)
 
bool copy (const std::filesystem::path &newName)
 
bool exists () const const
 
virtual QString fileName () const const override
 
std::filesystem::path filesystemFileName () const const
 
std::filesystem::path filesystemSymLinkTarget () const const
 
bool moveToTrash ()
 
bool open (FILE *fh, OpenMode mode, FileHandleFlags handleFlags)
 
bool open (int fd, OpenMode mode, FileHandleFlags handleFlags)
 
bool open (OpenMode mode, Permissions permissions)
 
virtual Permissions permissions () const const override
 
bool remove ()
 
bool rename (const QString &newName)
 
bool rename (const std::filesystem::path &newName)
 
virtual bool resize (qint64 sz) override
 
void setFileName (const QString &name)
 
void setFileName (const std::filesystem::path &name)
 
virtual bool setPermissions (Permissions permissions) override
 
virtual qint64 size () const const override
 
QString symLinkTarget () const const
 
- Public Member Functions inherited from QFileDevice
virtual bool atEnd () const const override
 
virtual void close () override
 
FileError error () const const
 
QDateTime fileTime (QFileDevice::FileTime time) const const
 
bool flush ()
 
int handle () const const
 
virtual bool isSequential () const const override
 
uchar * map (qint64 offset, qint64 size, MemoryMapFlags flags)
 
virtual qint64 pos () const const override
 
virtual bool seek (qint64 pos) override
 
bool setFileTime (const QDateTime &newDate, QFileDevice::FileTime fileTime)
 
bool unmap (uchar *address)
 
void unsetError ()
 
- Public Member Functions inherited from QIODevice
 QIODevice (QObject *parent)
 
void aboutToClose ()
 
virtual qint64 bytesAvailable () const const
 
virtual qint64 bytesToWrite () const const
 
void bytesWritten (qint64 bytes)
 
virtual bool canReadLine () const const
 
void channelBytesWritten (int channel, qint64 bytes)
 
void channelReadyRead (int channel)
 
void commitTransaction ()
 
int currentReadChannel () const const
 
int currentWriteChannel () const const
 
QString errorString () const const
 
bool getChar (char *c)
 
bool isOpen () const const
 
bool isReadable () const const
 
bool isTextModeEnabled () const const
 
bool isTransactionStarted () const const
 
bool isWritable () const const
 
QIODeviceBase::OpenMode openMode () const const
 
qint64 peek (char *data, qint64 maxSize)
 
QByteArray peek (qint64 maxSize)
 
bool putChar (char c)
 
qint64 read (char *data, qint64 maxSize)
 
QByteArray read (qint64 maxSize)
 
QByteArray readAll ()
 
int readChannelCount () const const
 
void readChannelFinished ()
 
qint64 readLine (char *data, qint64 maxSize)
 
QByteArray readLine (qint64 maxSize)
 
void readyRead ()
 
virtual bool reset ()
 
void rollbackTransaction ()
 
void setCurrentReadChannel (int channel)
 
void setCurrentWriteChannel (int channel)
 
void setTextModeEnabled (bool enabled)
 
qint64 skip (qint64 maxSize)
 
void startTransaction ()
 
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 &data)
 
int writeChannelCount () const const
 
- Public Member Functions inherited from QObject
 QObject (QObject *parent)
 
QBindable< QStringbindableObjectName ()
 
bool blockSignals (bool block)
 
const QObjectListchildren () const const
 
QMetaObject::Connection connect (const QObject *sender, const char *signal, const char *method, Qt::ConnectionType type) const const
 
void deleteLater ()
 
void destroyed (QObject *obj)
 
bool disconnect (const char *signal, const QObject *receiver, const char *method) const const
 
bool disconnect (const QObject *receiver, const char *method) const const
 
void dumpObjectInfo () const const
 
void dumpObjectTree () const const
 
QList< QByteArraydynamicPropertyNames () const const
 
virtual bool event (QEvent *e)
 
virtual bool eventFilter (QObject *watched, QEvent *event)
 
findChild (const QString &name, Qt::FindChildOptions options) const const
 
QList< T > findChildren (const QRegularExpression &re, Qt::FindChildOptions options) const const
 
QList< T > findChildren (const QString &name, Qt::FindChildOptions options) const const
 
QList< T > findChildren (Qt::FindChildOptions options) const const
 
bool inherits (const char *className) const const
 
void installEventFilter (QObject *filterObj)
 
bool isQuickItemType () const const
 
bool isWidgetType () const const
 
bool isWindowType () const const
 
void killTimer (int id)
 
virtual const QMetaObjectmetaObject () const const
 
void moveToThread (QThread *targetThread)
 
QString objectName () const const
 
void objectNameChanged (const QString &objectName)
 
QObjectparent () const const
 
QVariant property (const char *name) const const
 
 Q_CLASSINFO (Name, Value)
 
 Q_EMIT Q_EMIT
 
 Q_ENUM (...)
 
 Q_ENUM_NS (...)
 
 Q_ENUMS (...)
 
 Q_FLAG (...)
 
 Q_FLAG_NS (...)
 
 Q_FLAGS (...)
 
 Q_GADGET Q_GADGET
 
 Q_GADGET_EXPORT (EXPORT_MACRO)
 
 Q_INTERFACES (...)
 
 Q_INVOKABLE Q_INVOKABLE
 
 Q_MOC_INCLUDE Q_MOC_INCLUDE
 
 Q_NAMESPACE Q_NAMESPACE
 
 Q_NAMESPACE_EXPORT (EXPORT_MACRO)
 
 Q_OBJECT Q_OBJECT
 
 Q_PROPERTY (...)
 
 Q_REVISION Q_REVISION
 
 Q_SET_OBJECT_NAME (Object)
 
 Q_SIGNAL Q_SIGNAL
 
 Q_SIGNALS Q_SIGNALS
 
 Q_SLOT Q_SLOT
 
 Q_SLOTS Q_SLOTS
 
qobject_cast (const QObject *object)
 
qobject_cast (QObject *object)
 
 QT_NO_NARROWING_CONVERSIONS_IN_CONNECT QT_NO_NARROWING_CONVERSIONS_IN_CONNECT
 
void removeEventFilter (QObject *obj)
 
void setObjectName (const QString &name)
 
void setObjectName (QAnyStringView name)
 
void setParent (QObject *parent)
 
bool setProperty (const char *name, const QVariant &value)
 
bool setProperty (const char *name, QVariant &&value)
 
bool signalsBlocked () const const
 
int startTimer (int interval, Qt::TimerType timerType)
 
int startTimer (std::chrono::milliseconds interval, Qt::TimerType timerType)
 
QThreadthread () const const
 

Static Public Member Functions

static QList< KAutoSaveFile * > allStaleFiles (const QString &applicationName=QString())
 
static QList< KAutoSaveFile * > staleFiles (const QUrl &url, const QString &applicationName=QString())
 
- Static Public Member Functions inherited from QFile
bool copy (const QString &fileName, const QString &newName)
 
QString decodeName (const char *localFileName)
 
QString decodeName (const QByteArray &localFileName)
 
QByteArray encodeName (const QString &fileName)
 
bool exists (const QString &fileName)
 
std::filesystem::path filesystemSymLinkTarget (const std::filesystem::path &fileName)
 
bool moveToTrash (const QString &fileName, QString *pathInTrash)
 
Permissions permissions (const QString &fileName)
 
Permissions permissions (const std::filesystem::path &filename)
 
bool remove (const QString &fileName)
 
bool rename (const QString &oldName, const QString &newName)
 
bool resize (const QString &fileName, qint64 sz)
 
bool setPermissions (const QString &fileName, Permissions permissions)
 
bool setPermissions (const std::filesystem::path &filename, Permissions permissionSpec)
 
QString symLinkTarget (const QString &fileName)
 
- Static Public Member Functions inherited from QObject
QMetaObject::Connection connect (const QObject *sender, const char *signal, const QObject *receiver, const char *method, Qt::ConnectionType type)
 
QMetaObject::Connection connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type)
 
QMetaObject::Connection connect (const QObject *sender, PointerToMemberFunction signal, const QObject *context, Functor functor, Qt::ConnectionType type)
 
QMetaObject::Connection connect (const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method, Qt::ConnectionType type)
 
QMetaObject::Connection connect (const QObject *sender, PointerToMemberFunction signal, Functor functor)
 
bool disconnect (const QMetaObject::Connection &connection)
 
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)
 
bool disconnect (const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method)
 
QString tr (const char *sourceText, const char *disambiguation, int n)
 

Additional Inherited Members

- Public Types inherited from QFileDevice
enum  FileError
 
enum  FileHandleFlag
 
typedef  FileHandleFlags
 
enum  FileTime
 
enum  MemoryMapFlag
 
typedef  MemoryMapFlags
 
enum  Permission
 
typedef  Permissions
 
- Public Types inherited from QObject
typedef  QObjectList
 
- Public Types inherited from QIODeviceBase
typedef  OpenMode
 
enum  OpenModeFlag
 
- Properties inherited from QObject
 objectName
 
- Public Attributes inherited from QFileDevice
 AbortError
 
 AutoCloseHandle
 
 CopyError
 
 DontCloseHandle
 
 ExeGroup
 
 ExeOther
 
 ExeOwner
 
 ExeUser
 
 FatalError
 
 FileAccessTime
 
 FileBirthTime
 
 FileMetadataChangeTime
 
 FileModificationTime
 
 MapPrivateOption
 
 NoError
 
 NoOptions
 
 OpenError
 
 PermissionsError
 
 PositionError
 
 ReadError
 
 ReadGroup
 
 ReadOther
 
 ReadOwner
 
 ReadUser
 
 RemoveError
 
 RenameError
 
 ResizeError
 
 ResourceError
 
 TimeOutError
 
 UnspecifiedError
 
 WriteError
 
 WriteGroup
 
 WriteOther
 
 WriteOwner
 
 WriteUser
 
- Public Attributes inherited from QIODeviceBase
 Append
 
 ExistingOnly
 
 NewOnly
 
 NotOpen
 
 ReadOnly
 
 ReadWrite
 
 Text
 
 Truncate
 
 Unbuffered
 
 WriteOnly
 
- Protected Member Functions inherited from QFileDevice
virtual qint64 readData (char *data, qint64 len) override
 
virtual qint64 readLineData (char *data, qint64 maxlen) override
 
virtual qint64 writeData (const char *data, qint64 len) override
 
- Protected Member Functions inherited from QIODevice
void setErrorString (const QString &str)
 
void setOpenMode (QIODeviceBase::OpenMode openMode)
 
virtual qint64 skipData (qint64 maxSize)
 
- Protected Member Functions inherited from QObject
virtual void childEvent (QChildEvent *event)
 
virtual void connectNotify (const QMetaMethod &signal)
 
virtual void customEvent (QEvent *event)
 
virtual void disconnectNotify (const QMetaMethod &signal)
 
bool isSignalConnected (const QMetaMethod &signal) const const
 
int receivers (const char *signal) const const
 
QObjectsender () const const
 
int senderSignalIndex () const const
 
virtual void timerEvent (QTimerEvent *event)
 

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 QUrl &url)
{
// check whether autosave files exist:
if (!staleFiles.isEmpty()) {
"Auto-saved files exist. Do you want to recover them now?",
"File Recovery",
KGuiItem("Recover"), KGuiItem("Do Not recover")) == KMessageBox::PrimaryAction) {
recoverFiles(staleFiles);
return;
} else {
// remove the stale files
for (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'
...
}
Creates and manages a temporary "auto-save" file.
KAutoSaveFile(const QUrl &filename, QObject *parent=nullptr)
Constructs a KAutoSaveFile for file filename.
static QList< KAutoSaveFile * > staleFiles(const QUrl &url, const QString &applicationName=QString())
Checks for stale autosave files for the file url.
ButtonCode questionTwoActions(QWidget *parent, const QString &text, const QString &title, const KGuiItem &primaryAction, const KGuiItem &secondaryAction, const QString &dontAskAgainName=QString(), Options options=Notify)
QObject * parent() const const

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

for (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);
}
void setParent(QObject *parent)

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 120 of file kautosavefile.h.

Constructor & Destructor Documentation

◆ KAutoSaveFile() [1/2]

KAutoSaveFile::KAutoSaveFile ( const QUrl & filename,
QObject * parent = nullptr )
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
filenamethe filename that this KAutoSaveFile refers to
parentthe parent object

Definition at line 85 of file kautosavefile.cpp.

◆ KAutoSaveFile() [2/2]

KAutoSaveFile::KAutoSaveFile ( QObject * parent = nullptr)
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
parentthe parent object

Definition at line 92 of file kautosavefile.cpp.

◆ ~KAutoSaveFile()

KAutoSaveFile::~KAutoSaveFile ( )
override

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

Definition at line 98 of file kautosavefile.cpp.

Member Function Documentation

◆ allStaleFiles()

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.

The application owns all returned KAutoSaveFile objects and is responsible for deleting them when no longer needed. Remember that deleting the KAutoSaveFile will release the file lock and remove the stale autosave file.

Definition at line 227 of file kautosavefile.cpp.

◆ managedFile()

QUrl 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 104 of file kautosavefile.cpp.

◆ open()

bool KAutoSaveFile::open ( OpenMode openmode)
overridevirtual

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
openmodethe 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

Reimplemented from QFile.

Definition at line 128 of file kautosavefile.cpp.

◆ releaseLock()

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 117 of file kautosavefile.cpp.

◆ setManagedFile()

void KAutoSaveFile::setManagedFile ( const QUrl & 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
filenamethe filename that this KAutoSaveFile refers to

Definition at line 109 of file kautosavefile.cpp.

◆ staleFiles()

QList< KAutoSaveFile * > KAutoSaveFile::staleFiles ( const QUrl & url,
const QString & applicationName = QString() )
static

Checks for stale autosave files for the file url.

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.

The application owns all returned KAutoSaveFile objects and is responsible for deleting them when no longer needed. Remember that deleting the KAutoSaveFile will release the file lock and remove the stale autosave file.

Definition at line 199 of file kautosavefile.cpp.


The documentation for this class was generated from the following files:
This file is part of the KDE documentation.
Documentation copyright © 1996-2024 The KDE developers.
Generated on Fri Oct 11 2024 12:17:55 by doxygen 1.12.0 written by Dimitri van Heesch, © 1997-2006

KDE's Doxygen guidelines are available online.