dfilesystemwatcher_zh
2022-04-18 16:17:48

Class::DFileSystemWatcher

暂无该属性


Detailed Description

The DFileSystemWatcher class provides an interface for monitoring files and directories for modifications. DFileSystemWatcher monitors the file system for changes to files and directories by watching a list of specified paths.

Call addPath() to watch a particular file or directory. Multiple paths can be added using the addPaths() function. Existing paths can be removed by using the removePath() and removePaths() functions.

DFileSystemWatcher examines each path added to it. Files that have been added to the DFileSystemWatcher can be accessed using the files() function, and directories using the directories() function.

The fileChanged() signal is emitted when a file has been modified, renamed or removed from disk. Similarly, the directoryChanged() signal is emitted when a directory or its contents is modified or removed. Note that DFileSystemWatcher stops monitoring files once they have been renamed or removed from disk, and directories once they have been removed from disk.

Note: On systems running a Linux kernel without inotify support, file systems that contain watched paths cannot be unmounted.

Note: Windows CE does not support directory monitoring by default as this depends on the file system driver installed.

Note: The act of monitoring files and directories for modifications consumes system resources. This implies there is a limit to the number of files and directories your process can monitor simultaneously. On all BSD variants, for example, an open file descriptor is required for each monitored file. Some system limits the number of open file descriptors to 256 by default. This means that addPath() and addPaths() will fail if your process tries to add more than 256 files or directories to the file system monitor. Also note that your process may have other file descriptors open in addition to the ones for files being monitored, and these other open descriptors also count in the total. OS X uses a different backend and does not suffer from this issue.

See also QFileQDir

DFileSystemWatcher::metaObject

[public plain  virtual]

const QMetaObject * metaObject() const

DFileSystemWatcher::qt_metacast

[public plain  virtual]

void * qt_metacast(const char *)

DFileSystemWatcher::qt_metacall

[public plain  virtual]

int qt_metacall(QMetaObject::Call , int , void **)

DFileSystemWatcher::tr

[public plain static ]

QString tr(const char *s, const char *c, int n)

DFileSystemWatcher::trUtf8

[public plain static ]

QString trUtf8(const char *s, const char *c, int n)

DFileSystemWatcher::qt_static_metacall

[private plain static ]

void qt_static_metacall(QObject *, QMetaObject::Call , int , void **)

Class::QPrivateSignal

DFileSystemWatcher::QPrivateSignal


Detailed Description

DFileSystemWatcher::d_func

[private plain  ]

DFileSystemWatcherPrivate * d_func()

DFileSystemWatcher::d_func

[private plain  ]

const DFileSystemWatcherPrivate * d_func() const

DFileSystemWatcher::DFileSystemWatcher

[public constructor  ]

DFileSystemWatcher(QObject *parent) Constructs a new file system watcher object with the given parent.

DFileSystemWatcher::DFileSystemWatcher

[public constructor  ]

DFileSystemWatcher(const QStringList &paths, QObject *parent) Constructs a new file system watcher object with the given parent which monitors the specified paths list.

DFileSystemWatcher::~DFileSystemWatcher

[public destructor  virtual]

~DFileSystemWatcher() Destroys the file system watcher.

DFileSystemWatcher::addPath

[public plain  ]

bool addPath(const QString &path) Adds path to the file system watcher if path exists. The path is not added if it does not exist, or if it is already being monitored by the file system watcher.

If path specifies a directory, the directoryChanged() signal will be emitted when path is modified or removed from disk; otherwise the fileChanged() signal is emitted when path is modified, renamed or removed.

If the watch was successful, true is returned.

Reasons for a watch failure are generally system-dependent, but may include the resource not existing, access failures, or the total watch count limit, if the platform has one.

Note: There may be a system dependent limit to the number of files and directories that can be monitored simultaneously. If this limit is been reached, path will not be monitored, and false is returned.

See also addPaths() removePath()

DFileSystemWatcher::addPaths

[public plain  ]

QStringList addPaths(const QStringList &paths) Adds each path in paths to the file system watcher. Paths are not added if they not exist, or if they are already being monitored by the file system watcher.

If a path specifies a directory, the directoryChanged() signal will be emitted when the path is modified or removed from disk; otherwise the fileChanged() signal is emitted when the path is modified, renamed, or removed.

The return value is a list of paths that could not be watched.

Reasons for a watch failure are generally system-dependent, but may include the resource not existing, access failures, or the total watch count limit, if the platform has one.

Note: There may be a system dependent limit to the number of files and directories that can be monitored simultaneously. If this limit has been reached, the excess paths will not be monitored, and they will be added to the returned QStringList.

See also addPath() removePaths()

DFileSystemWatcher::removePath

[public plain  ]

bool removePath(const QString &path) Removes the specified path from the file system watcher.

If the watch is successfully removed, true is returned.

Reasons for watch removal failing are generally system-dependent, but may be due to the path having already been deleted, for example.

See also removePaths() addPath()

DFileSystemWatcher::removePaths

[public plain  ]

QStringList removePaths(const QStringList &paths) Removes the specified paths from the file system watcher.

The return value is a list of paths which were not able to be unwatched successfully.

Reasons for watch removal failing are generally system-dependent, but may be due to the path having already been deleted, for example.

See also removePath() addPaths()

DFileSystemWatcher::files

[public plain  ]

QStringList files() const

DFileSystemWatcher::directories

[public plain  ]

QStringList directories() const

DFileSystemWatcher::fileDeleted

[public signal  ]

void fileDeleted(const QString &path, const QString &name)

DFileSystemWatcher::fileAttributeChanged

[public signal  ]

void fileAttributeChanged(const QString &path, const QString &name)

DFileSystemWatcher::fileClosed

[public signal  ]

void fileClosed(const QString &path, const QString &name)

DFileSystemWatcher::fileMoved

[public signal  ]

void fileMoved(const QString &fromPath, const QString &fromName, const QString &toPath, const QString &toName)

DFileSystemWatcher::fileCreated

[public signal  ]

void fileCreated(const QString &path, const QString &name)

DFileSystemWatcher::fileModified

[public signal  ]

void fileModified(const QString &path, const QString &name)