CopperSpice API  1.7.4
QFileInfo Class Reference

The QFileInfo class provides system independent file information. More...

Public Methods

 QFileInfo ()
 
 QFileInfo (const QDir &dir, const QString &file)
 
 QFileInfo (const QFile &file)
 
 QFileInfo (const QFileInfo &fileinfo)
 
 QFileInfo (const QString &file)
 
 ~QFileInfo ()
 
QDir absoluteDir () const
 
QString absoluteFilePath () const
 
QString absolutePath () const
 
QString baseName () const
 
QString bundleName () const
 
bool caching () const
 
QString canonicalFilePath () const
 
QString canonicalPath () const
 
QString completeBaseName () const
 
QString completeSuffix () const
 
QDateTime created () const
 
QDir dir () const
 
bool exists () const
 
QString fileName () const
 
QString filePath () const
 
QString group () const
 
uint groupId () const
 
bool isAbsolute () const
 
bool isBundle () const
 
bool isDir () const
 
bool isExecutable () const
 
bool isFile () const
 
bool isHidden () const
 
bool isNativePath () const
 
bool isReadable () const
 
bool isRelative () const
 
bool isRoot () const
 
bool isSymLink () const
 
bool isWritable () const
 
QDateTime lastModified () const
 
QDateTime lastRead () const
 
bool makeAbsolute ()
 
bool operator!= (const QFileInfo &fileinfo) const
 
QFileInfo & operator= (const QFileInfo &fileinfo)
 
QFileInfo & operator= (QFileInfo &&other)
 
bool operator== (const QFileInfo &fileinfo) const
 
QString owner () const
 
uint ownerId () const
 
QString path () const
 
bool permission (QFile::Permissions permissions) const
 
QFile::Permissions permissions () const
 
QString readLink () const
 
void refresh ()
 
void setCaching (bool enable)
 
void setFile (const QDir &dir, const QString &file)
 
void setFile (const QFile &file)
 
void setFile (const QString &file)
 
qint64 size () const
 
QString suffix () const
 
QString symLinkTarget () const
 

Related Functions

These are not member functions

 QFileInfoList
 

Detailed Description

The QFileInfo class provides system independent file information. This class provides information about a file's name and position (path) in the file system, its access rights and whether it is a directory or symbolic link, etc. The file's size and last modified/read times are also available. QFileInfo can also be used to obtain information about a CopperSpice resource.

A QFileInfo can point to a file with either a relative or an absolute file path. Absolute file paths begin with the directory separator "/" (or with a drive specification on Windows). Relative file names begin with a directory name or a file name and specify a path relative to the current working directory. An example of an absolute path is the string "/tmp/quartz". A relative path might look like "src/fatlib". You can use the method isRelative() to check whether a QFileInfo is using a relative or an absolute file path. You can call the method makeAbsolute() to convert a relative QFileInfo's path to an absolute path.

The file for a QFileInfo object is set in the constructor or by calling setFile(). Call exists() to verify if the file is present and call size() to get its size. The file's type is obtained with isFile(), isDir() and isSymLink().

On Unix and Mac OS X, the symlink has the same size as the file it points to. Opening a symlink using QFile effectively opens the link's target.

#ifdef Q_OS_UNIX
QFileInfo info1("/home/bob/bin/untabify");
info1.isSymLink(); // returns true
info1.absoluteFilePath(); // returns "/home/bob/bin/untabify"
info1.size(); // returns 56201
info1.symLinkTarget(); // returns "/opt/pretty++/bin/untabify"
QFileInfo info2(info1.symLinkTarget());
info2.isSymLink(); // returns false
info2.absoluteFilePath(); // returns "/opt/pretty++/bin/untabify"
info2.size(); // returns 56201
#endif

On Windows, symlinks (shortcuts) are .lnk files. The reported size() is that of the symlink (not the link's target), and opening a symlink using QFile opens the .lnk file. For example:

#ifdef Q_OS_WIN
QFileInfo info1("C:\Documents and Settings\Bob\untabify.lnk");
info1.isSymLink(); // returns true
info1.absoluteFilePath(); // returns "C:/Documents and Settings/Bob/untabify.lnk"
info1.size(); // returns 743
info1.symLinkTarget(); // returns "C:/Pretty++/untabify"
QFileInfo info2(info1.symLinkTarget());
info2.isSymLink(); // returns false
info2.absoluteFilePath(); // returns "C:/Pretty++/untabify"
info2.size(); // returns 63942
#endif

Elements of the file's name can be extracted with path() and fileName(). The fileName()'s parts can be extracted with baseName(), suffix() or completeSuffix(). QFileInfo objects to directories, created by CopperSpice classes, will not have a trailing file separator. If you want to use trailing separators in your file info objects, append one to the file name given to the constructors or setFile().

The file's dates are returned by created(), lastModified() and lastRead(). Information about the file's access permissions is obtained with isReadable(), isWritable() and isExecutable(). The file's ownership is available from owner(), ownerId(), group() and groupId(). You can examine a file's permissions and ownership in a single statement using the permission() method.

Performance Issues

Some of the methods in this class will query the file system. For performance reasons, some methods only operate on the file name itself. For example, to return the absolute path of a relative file name, absolutePath() has to query the file system. The path() method can work on the file name directly, and so it is faster.

To speed up performance, QFileInfo caches information about the file. Since files can be changed by other users, programs or other parts of the same program, the refreh() method can be called to refreshe the file information. If you want to switch off a QFileInfo's caching and force it to access the file system every time you request information from it call setCaching(false).

See also
QDir, QFile

Constructor & Destructor Documentation

QFileInfo::QFileInfo ( )

Constructs an empty QFileInfo object.

See also
setFile()
QFileInfo::QFileInfo ( const QString file)

Constructs a new QFileInfo which contains information about the given file. The file can also include an absolute or relative path.

See also
setFile(), isRelative(), QDir::setCurrent(), QDir::isRelativePath()
QFileInfo::QFileInfo ( const QFile file)

Constructs a new QFileInfo using the given file. If the file has a relative path the QFileInfo will also have a relative path.

See also
isRelative()
QFileInfo::QFileInfo ( const QDir dir,
const QString file 
)

Constructs a new QFileInfo using the given file from the given dir. If dir has a relative path, the QFileInfo will also have a relative path. If file is an absolute path then the directory specified by dir will be disregarded.

See also
isRelative()
QFileInfo::QFileInfo ( const QFileInfo &  fileinfo)

Constructs a new QFileInfo that is a copy of the given i>fileinfo.

QFileInfo::~QFileInfo ( )

Destroys the QFileInfo and frees its resources.

Method Documentation

QDir QFileInfo::absoluteDir ( ) const

Returns the file's absolute path as a QDir object.

See also
dir(), filePath(), fileName(), isRelative()
QString QFileInfo::absoluteFilePath ( ) const

Returns an absolute path including the file name. If the QFileInfo is empty it returns QDir::currentPath(). Returns the same as filePath(), unless isRelative() is true. In contrast to canonicalFilePath(), symbolic links or redundant "." or ".." elements are not necessarily removed.

The absolute path name consists of the full path and the file name. On Unix this will always begin with the root, '/', directory. On Windows this will always begin 'D:/' where D is a drive letter, except for network shares that are not mapped to a drive letter, in which case the path will begin '//sharename/'. QFileInfo will uppercase drive letters however QDir does not do this.

QFileInfo fi("c:/temp/foo"); => fi.absoluteFilePath() => "C:/temp/foo"
See also
filePath(), canonicalFilePath(), isRelative()
QString QFileInfo::absolutePath ( ) const

Returns the absolute path for this file which does not include the file name. In contrast to the method canonicalPath(), symbolic links or redundant "." or ".." elements are not necessarily removed. If the QFileInfo object was created with an empty QString the behavior of this method is undefined.

On Unix the absolute path will always begin with the root, '/', directory. On Windows this will always begin 'D:/' where D is a drive letter, except for network shares that are not mapped to a drive letter, in which case the path will begin '//sharename/'.

See also
absoluteFilePath(), path(), canonicalPath(), fileName(), isRelative()
QString QFileInfo::baseName ( ) const

Returns the base name of the file without the path. The base name consists of all characters in the file up to (but not including) the first '.' character.

QFileInfo fi("/tmp/archive.tar.gz");
QString base = fi.baseName(); // base = "archive"

The base name of a file is computed equally on all platforms, independent of file naming conventions (e.g., ".bashrc" on Unix has an empty base name, and the suffix is "bashrc").

See also
fileName(), suffix(), completeSuffix(), completeBaseName()
QString QFileInfo::bundleName ( ) const

Returns the name of the bundle. On Mac OS X this returns the proper localized name for a bundle if the path isBundle(). On all other platforms an empty QString is returned.

QFileInfo fi("/Applications/Safari.app");
QString bundle = fi.bundleName(); // name = "Safari"
See also
isBundle(), filePath(), baseName(), suffix(), completeSuffix()
bool QFileInfo::caching ( ) const

Returns true if caching is enabled, otherwise returns false.

See also
setCaching(), refresh()
QString QFileInfo::canonicalFilePath ( ) const

Returns the canonical path including the file name. This is an absolute path without symbolic links or redundant "." or ".." elements. If the file does not exist, canonicalFilePath() returns an empty string.

See also
filePath(), absoluteFilePath(), dir()
QString QFileInfo::canonicalPath ( ) const

Returns the file's path canonical path excluding the file name. This is an absolute path without symbolic links or redundant "." or ".." elements.

If the file does not exist, canonicalPath() returns an empty string.

See also
path(), absolutePath()
QString QFileInfo::completeBaseName ( ) const

Returns the complete base name of the file without the path. The complete base name consists of all characters in the file up to but not including the last '.' character.

QFileInfo fi("/tmp/archive.tar.gz");
QString base = fi.completeBaseName(); // base = "archive.tar"
See also
fileName(), suffix(), completeSuffix(), baseName()
QString QFileInfo::completeSuffix ( ) const

Returns the complete suffix of the file. The complete suffix consists of all characters in the file after but not including the first '.'.

QFileInfo fi("/tmp/archive.tar.gz");
QString ext = fi.completeSuffix(); // ext = "tar.gz"
See also
fileName(), suffix(), baseName(), completeBaseName()
QDateTime QFileInfo::created ( ) const

Returns the date and time when the file was created.

On most Unix systems this method returns the time of the last status change. A status change occurs when the file is created but it also occurs whenever the user changes meta data file. For example, when the file permissions are changed.

If neither creation time nor "last status change" time are available, this method returns the same as calling lastModified().

See also
lastModified(), lastRead()
QDir QFileInfo::dir ( ) const

Returns the path of the object's parent directory as a QDir object. The return value always corresponds to the object's parent directory, even if the QFileInfo represents a directory.

For each of the following, calling dir() returns a QDir for "~/examples/191697".

QFileInfo fileInfo1("~/examples/191697/.");
QFileInfo fileInfo2("~/examples/191697/..");
QFileInfo fileInfo3("~/examples/191697/main.cpp");

For each of the following calling dir() returns a QDir for ".".

QFileInfo fileInfo4(".");
QFileInfo fileInfo5("..");
QFileInfo fileInfo6("main.cpp");
See also
absolutePath(), filePath(), fileName(), isRelative(), absoluteDir()
bool QFileInfo::exists ( ) const

Returns true if the file exists, otherwise returns false.

Note
If the file is a symlink that points to a non existing file, false is returned.
QString QFileInfo::fileName ( ) const

Returns the name of the file, excluding the path. If this QFileInfo object is given a path ending in a slash, the name of the file is considered empty.

QFileInfo fi("/tmp/archive.tar.gz");
QString name = fi.fileName(); // name = "archive.tar.gz"
See also
isRelative(), filePath(), baseName(), suffix(), completeSuffix()
QString QFileInfo::filePath ( ) const

Returns the file name, including the path (which may be absolute or relative).

See also
absoluteFilePath(), canonicalFilePath(), isRelative()
QString QFileInfo::group ( ) const

Returns the group of the file. On Windows, on systems where files do not have groups, or if an error occurs, an empty string is returned. This method can be time consuming under Unix (in the order of milliseconds).

See also
groupId(), owner(), ownerId()
uint QFileInfo::groupId ( ) const

Returns the id of the group the file belongs to. On Windows and on systems where files do not have groups this method always returns (uint) -2.

See also
group(), owner(), ownerId()
bool QFileInfo::isAbsolute ( ) const
inline

Returns true if the file path name is absolute, otherwise returns false if the path is relative.

See also
isRelative()
bool QFileInfo::isBundle ( ) const

Returns true if this object points to a bundle or to a symbolic link to a bundle on Mac OS X, otherwise returns false.

See also
isDir(), isSymLink(), isFile()
bool QFileInfo::isDir ( ) const

Returns true if this object points to a directory or to a symbolic link to a directory, otherwise returns false.

See also
isFile(), isSymLink(), isBundle()
bool QFileInfo::isExecutable ( ) const

Returns true if the file is executable, otherwise returns false.

See also
isReadable(), isWritable(), permission()
bool QFileInfo::isFile ( ) const

Returns true if this object points to a file or to a symbolic link to a file. Returns false if the object points to something which is not a file, such as a directory.

See also
isDir(), isSymLink(), isBundle()
bool QFileInfo::isHidden ( ) const

Returns true if this is a ‘hidden’ file, otherwise returns false.

Note
Returns true for the special entries "." and ".." on Unix, even though QDir::entryList threats them as shown.
bool QFileInfo::isNativePath ( ) const

Returns true if the file path can be used directly with native APIs. Returns false if the file is otherwise supported by a virtual file system inside CopperSpice, such as the Resource System.

Note
Native paths may still require conversion of path separators and character encoding, depending on platform and input requirements of the native API.
See also
QDir::toNativeSeparators(), QFile::encodeName(), filePath(), absoluteFilePath(), canonicalFilePath()
bool QFileInfo::isReadable ( ) const

Returns true if the user can read the file, otherwise returns false.

See also
isWritable(), isExecutable(), permission()
bool QFileInfo::isRelative ( ) const

Returns true if the file path name is relative, otherwise returns false if the path is absolute (e.g. under Unix a path is absolute if it begins with a "/").

See also
isAbsolute()
bool QFileInfo::isRoot ( ) const

Returns true if the object points to a directory or to a symbolic link to a directory, and that directory is the root directory, otherwise returns false.

bool QFileInfo::isSymLink ( ) const

Returns true if this object points to a symbolic link (or to a shortcut on Windows), otherwise returns false. On Unix and Mac OS X, opening a symlink effectively opens the link's target. On Windows, it opens the .lnk file itself.

if (info.isSymLink()) {
fileName = info.symLinkTarget();
}
Note
If the symlink points to a non existing file, calling exists() returns false.
See also
isFile(), isDir(), symLinkTarget()
bool QFileInfo::isWritable ( ) const

Returns true if the user can write to the file, otherwise returns false.

See also
isReadable(), isExecutable(), permission()
QDateTime QFileInfo::lastModified ( ) const

Returns the date and time when the file was last modified.

See also
created(), lastRead()
QDateTime QFileInfo::lastRead ( ) const

Returns the date and time when the file was last read or accessed. On platforms where this information is not available, returns the same as lastModified().

See also
created(), lastModified()
bool QFileInfo::makeAbsolute ( )

Converts the file's path to an absolute path if it is not already in that form. Returns true to indicate that the path was converted, otherwise returns false to indicate that the path was already absolute.

See also
filePath(), isRelative()
bool QFileInfo::operator!= ( const QFileInfo &  fileinfo) const
inline

Returns true if this QFileInfo object refers to a different file than the one specified by fileinfo, otherwise returns false.

QFileInfo & QFileInfo::operator= ( const QFileInfo &  fileinfo)

Copy assigns from other and returns a reference to this object.

QFileInfo & QFileInfo::operator= ( QFileInfo &&  other)
inline

Move assigns from other and returns a reference to this object.

bool QFileInfo::operator== ( const QFileInfo &  fileinfo) const

Returns true if this QFileInfo object refers to a file in the same location as fileinfo, otherwise returns false. The result of comparing two empty QFileInfo objects, containing no file references, is undefined.

Warning
This method will not compare two different symbolic links pointing to the same file. Long and short file names which refer to the same file on Windows are treated as if they referred to different files.
See also
operator!=()
QString QFileInfo::owner ( ) const

Returns the owner of the file. On systems where files do not have owners, or if an error occurs, an empty string is returned. This method can be time consuming under Unix.

See also
ownerId(), group(), groupId()
uint QFileInfo::ownerId ( ) const

Returns the id of the owner of the file. On Windows and on systems where files do not have owners this method returns ((uint) -2).

See also
owner(), group(), groupId()
QString QFileInfo::path ( ) const

Returns the file's path. This does not include the file name. If this QFileInfo object is given a path ending in a slash, the name of the file is considered empty and this method will return the entire path.

See also
filePath(), absolutePath(), canonicalPath(), dir(), fileName(), isRelative()
bool QFileInfo::permission ( QFile::Permissions  permissions) const

Tests for file permissions. The permissions argument can be several flags of type QFile::Permissions OR-ed together to check for permission combinations. On systems where files do not have permissions this method always returns true.

QFileInfo fi("/tmp/archive.tar.gz");
if (fi.permission(QFile::WriteUser | QFile::ReadGroup)) {
qWarning("I can change the file; my group can read the file");
}
if (fi.permission(QFile::WriteGroup | QFile::WriteOther)) {
qWarning("The group or others can change the file");
}
See also
isReadable(), isWritable(), isExecutable()
QFile::Permissions QFileInfo::permissions ( ) const

Returns the complete OR-ed together combination of QFile::Permissions for the file.

QString QFileInfo::readLink ( ) const
deprecated
void QFileInfo::refresh ( )

Refreshes the information about the file and reads information directly from the file system the next time a cached property is fetched.

void QFileInfo::setCaching ( bool  enable)

If enable is true, enables caching of file information. If enable is false caching is disabled. When caching is enabled, QFileInfo reads the file information from the file system the first time it's needed, but generally not later.

Caching is enabled by default.

See also
refresh(), caching()
void QFileInfo::setFile ( const QDir dir,
const QString file 
)

Sets the file that the QFileInfo provides information about to file in directory dir. If file includes a relative path, the QFileInfo will also have a relative path.

See also
isRelative()
void QFileInfo::setFile ( const QFile file)

Sets the file that the QFileInfo provides information about to file. If file includes a relative path, the QFileInfo will also have a relative path.

See also
isRelative()
void QFileInfo::setFile ( const QString file)

Sets the file that the QFileInfo provides information about to file.

The file can also include an absolute or relative file path. Absolute paths begin with the directory separator (e.g. "/" under Unix) or a drive specification (under Windows). Relative file names begin with a directory name or a file name and specify a path relative to the current directory.

QString absolute = "/local/bin";
QString relative = "local/bin";
QFileInfo absFile(absolute);
QFileInfo relFile(relative);
QDir::setCurrent(QDir::rootPath()); // absFile and relFile point to the same file
QDir::setCurrent("/tmp"); // absFile points to "/local/bin", relFile points to "/tmp/local/bin"
See also
isFile(), isRelative(), QDir::setCurrent(), QDir::isRelativePath()
qint64 QFileInfo::size ( ) const

Returns the file size in bytes. If the file does not exist or can not be fetched then 0 is returned.

See also
exists()
QString QFileInfo::suffix ( ) const

Returns the suffix of the file. The suffix consists of all characters in the file after but not including the last '.'. The suffix of a file is computed equally on all platforms, independent of file naming conventions (e.g., ".bashrc" on Unix has an empty base name, and the suffix is "bashrc").

QFileInfo fi("/tmp/archive.tar.gz");
QString ext = fi.suffix(); // ext = "gz"
See also
fileName(), completeSuffix(), baseName(), completeBaseName()
QString QFileInfo::symLinkTarget ( ) const
inline

Returns the absolute path to the file or directory a symlink (or shortcut on Windows) points to, or an empty string if the object is not a symbolic link. The name may not represent an actual file, since it is only a string. QFileInfo::exists() returns true if the symlink points to an existing file.

See also
exists(), isSymLink(), isDir(), isFile()

Friends And Related Function Documentation

QFileInfoList ( )
related

Synonym for QList<QFileInfo>.