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PFile Class Reference

#include <file.h>

Inheritance diagram for PFile:

PChannel PObject PMemoryFile PStructuredFile PTextFile PWAVFile List of all members.

Construction

enum  OpenMode { ReadOnly, WriteOnly, ReadWrite }
enum  OpenOptions {
  ModeDefault = -1, MustExist = 0, Create = 1, Truncate = 2,
  Exclusive = 4, Temporary = 8, DenySharedRead = 16, DenySharedWrite = 32
}
 PFile ()
 PFile (OpenMode mode, int opts=ModeDefault)
 PFile (const PFilePath &name, OpenMode mode=ReadWrite, int opts=ModeDefault)
 ~PFile ()
 Close the file on destruction.


File channel functions

enum  FilePositionOrigin { Start = SEEK_SET, Current = SEEK_CUR, End = SEEK_END }
 Options for the origin in setting the file position. More...

const PFilePathGetFilePath () const
void SetFilePath (const PString &path)
virtual BOOL Open (OpenMode mode=ReadWrite, int opts=ModeDefault)
virtual BOOL Open (const PFilePath &name, OpenMode mode=ReadWrite, int opts=ModeDefault)
virtual off_t GetLength () const
virtual BOOL SetLength (off_t len)
virtual BOOL SetPosition (off_t pos, FilePositionOrigin origin=Start)
virtual off_t GetPosition () const
BOOL IsEndOfFile () const
BOOL GetInfo (PFileInfo &info)
BOOL SetPermissions (int permissions)
BOOL GetInfo (const PFilePath &name, PFileInfo &info)
BOOL SetPermissions (const PFilePath &name, int permissions)

File manipulation functions

BOOL Exists () const
BOOL Access (OpenMode mode)
BOOL Remove (BOOL force=FALSE)
BOOL Rename (const PString &newname, BOOL force=FALSE)
BOOL Copy (const PFilePath &newname, BOOL force=FALSE)
BOOL Move (const PFilePath &newname, BOOL force=FALSE)
BOOL Exists (const PFilePath &name)
BOOL Access (const PFilePath &name, OpenMode mode)
BOOL Remove (const PFilePath &name, BOOL force=FALSE)
BOOL Rename (const PFilePath &oldname, const PString &newname, BOOL force=FALSE)
BOOL Copy (const PFilePath &oldname, const PFilePath &newname, BOOL force=FALSE)
BOOL Move (const PFilePath &oldname, const PFilePath &newname, BOOL force=FALSE)

Public Types


Public Member Functions

Overrides from class PObject
Comparison Compare (const PObject &obj) const
Overrides from class PChannel
virtual PString GetName () const
virtual BOOL Read (void *buf, PINDEX len)
virtual BOOL Write (const void *buf, PINDEX len)
virtual BOOL Close ()

Protected Attributes

PFilePath path
 The fully qualified path name for the file.

BOOL removeOnClose
 File is to be removed when closed.


Detailed Description

This class represents a disk file. This is a particular type of I/O channel that has certain attributes. All platforms have a disk file, though exact details of naming convertions etc may be different.

The basic model for files is that they are a named sequence of bytes that persists within a directory structure. The transfer of data to and from the file is made at a current position in the file. This may be set to random locations within the file.


Member Enumeration Documentation

enum PFile::FilePositionOrigin
 

Options for the origin in setting the file position.

Enumeration values:
Start  Set position relative to start of file.
Current  Set position relative to current file position.
End  Set position relative to end of file.

enum PFile::OpenMode
 

When a file is opened, it may restrict the access available to operations on the object instance. A value from this enum is passed to the #Open()# function to set the mode.

Enumeration values:
ReadOnly  File can be read but not written.
WriteOnly  File can be written but not read.
ReadWrite  File can be both read and written.

enum PFile::OpenOptions
 

When a file is opened, a number of options may be associated with the open file. These describe what action to take on opening the file and what to do on closure. A value from this enum is passed to the #Open()# function to set the options.

The ModeDefault# option will use the following values: {tabular}{rr} Mode & Options \ ReadOnly# & MustExist# \ WriteOnly# & Create | Truncate# \ ReadWrite# & Create# \ {tabular}

Enumeration values:
ModeDefault  File options depend on the OpenMode parameter.
MustExist  File open fails if file does not exist.
Create  File is created if it does not exist.
Truncate  File is set to zero length if it already exists.
Exclusive  File open fails if file already exists.
Temporary  File is temporary and is to be deleted when closed.
DenySharedRead  File may not be read by another process.
DenySharedWrite  File may not be written by another process.


Constructor & Destructor Documentation

PINLINE PFile::PFile  ) 
 

Create a file object but do not open it. It does not initially have a valid file name. However, an attempt to open the file using the #Open()# function will generate a unique temporary file.

PINLINE PFile::PFile OpenMode  mode,
int  opts = ModeDefault
 

Create a unique temporary file name, and open the file in the specified mode and using the specified options. Note that opening a new, unique, temporary file name in ReadOnly mode will always fail. This would only be usefull in a mode and options that will create the file.

The #PChannel::IsOpen()# function may be used after object construction to determine if the file was successfully opened.

Parameters:
opts  Mode in which to open the file. OpenOptions enum# for open operation.

PINLINE PFile::PFile const PFilePath name,
OpenMode  mode = ReadWrite,
int  opts = ModeDefault
 

Create a file object with the specified name and open it in the specified mode and with the specified options.

The #PChannel::IsOpen()# function may be used after object construction to determine if the file was successfully opened.

Parameters:
mode  Name of file to open.
opts  Mode in which to open the file. OpenOptions enum# for open operation.

PFile::~PFile  ) 
 

Close the file on destruction.


Member Function Documentation

PINLINE BOOL PFile::Access OpenMode  mode  ) 
 

Check for file access modes. Determine if the file path specification associated with the instance of the object may be opened in the specified mode. This would check the current access rights to the file for the mode. For example, for a file that is read only, using mode == ReadWrite would return FALSE but mode == ReadOnly would return TRUE.

Returns:
TRUE if a file open would succeed.
Parameters:
mode  Mode in which the file open would be done.

BOOL PFile::Access const PFilePath name,
OpenMode  mode
[static]
 

Check for file access modes. Determine if the file specified may be opened in the specified mode. This would check the current access rights to the file for the mode. For example, for a file that is read only, using mode == ReadWrite would return FALSE but mode == ReadOnly would return TRUE.

Returns:
TRUE if a file open would succeed.
Parameters:
mode  Name of file to have its access checked. Mode in which the file open would be done.

virtual BOOL PFile::Close  )  [virtual]
 

Close the file channel.

Returns:
TRUE if close was OK.

Reimplemented from PChannel.

Reimplemented in PWAVFile.

Comparison PFile::Compare const PObject obj  )  const [virtual]
 

Determine the relative rank of the two objects. This is essentially the string comparison of the PFilePath# names of the files.

Returns:
relative rank of the file paths.
Parameters:
obj  Other file to compare against.

Reimplemented from PChannel.

Reimplemented in PMemoryFile.

PINLINE BOOL PFile::Copy const PFilePath newname,
BOOL  force = FALSE
 

Make a copy of the current file.

Returns:
TRUE if the file was renamed.
Parameters:
force  New name for the file. Delete file if a destination exists with the same name.

BOOL PFile::Copy const PFilePath oldname,
const PFilePath newname,
BOOL  force = FALSE
[static]
 

Make a copy of the specified file.

Returns:
TRUE if the file was renamed.
Parameters:
newname  Old name of the file.
force  New name for the file. Delete file if a destination exists with the same name.

PINLINE BOOL PFile::Exists  )  const
 

Check for file existance. Determine if the file path specification associated with the instance of the object actually exists within the platforms file system.

Returns:
TRUE if the file exists.

BOOL PFile::Exists const PFilePath name  )  [static]
 

Check for file existance. Determine if the file specified actually exists within the platforms file system.

Returns:
TRUE if the file exists.
Parameters:
name  Name of file to see if exists.

PINLINE const PFilePath & PFile::GetFilePath  )  const
 

Get the full path name of the file. The PFilePath# object describes the full file name specification for the particular platform.

Returns:
the name of the file.

PINLINE BOOL PFile::GetInfo PFileInfo info  ) 
 

Get information (eg protection, timestamps) on the current file.

Returns:
TRUE if the file info was retrieved.

BOOL PFile::GetInfo const PFilePath name,
PFileInfo info
[static]
 

Get information (eg protection, timestamps) on the specified file.

Returns:
TRUE if the file info was retrieved.

virtual off_t PFile::GetLength  )  const [virtual]
 

Get the current size of the file.

Returns:
length of file in bytes.

Reimplemented in PMemoryFile.

PINLINE PString PFile::GetName  )  const [virtual]
 

Get the platform and I/O channel type name of the channel. For example, it would return the filename in PFile# type channels.

Returns:
the name of the channel.

Reimplemented from PChannel.

PINLINE off_t PFile::GetPosition  )  const [virtual]
 

Get the current active position in the file for the next read or write operation.

Returns:
current file position relative to start of file.

Reimplemented in PMemoryFile, and PWAVFile.

BOOL PFile::IsEndOfFile  )  const
 

Determine if the current file position is at the end of the file. If this is TRUE then any read operation will fail.

Returns:
TRUE if at end of file.

BOOL PFile::Move const PFilePath newname,
BOOL  force = FALSE
 

Move the current file. This will move the file from one position in the directory hierarchy to another position. The actual operation is platform dependent but the reslt is the same. For instance, for Unix, if the move is within a file system then a simple rename is done, if it is across file systems then a copy and a delete is performed.

Returns:
TRUE if the file was moved.
Parameters:
force  New path and name for the file. Delete file if a destination exists with the same name.

BOOL PFile::Move const PFilePath oldname,
const PFilePath newname,
BOOL  force = FALSE
[static]
 

Move the specified file. This will move the file from one position in the directory hierarchy to another position. The actual operation is platform dependent but the reslt is the same. For instance, for Unix, if the move is within a file system then a simple rename is done, if it is across file systems then a copy and a delete is performed.

Returns:
TRUE if the file was moved.
Parameters:
newname  Old path and name of the file.
force  New path and name for the file. Delete file if a destination exists with the same name.

virtual BOOL PFile::Open const PFilePath name,
OpenMode  mode = ReadWrite,
int  opts = ModeDefault
[virtual]
 

Open the specified file name in the specified mode and with the specified options. If the file object already has an open file then it is closed.

Note: if #mode# is StandardInput, StandardOutput or StandardError, then the #name# parameter is ignored.

Returns:
TRUE if the file was successfully opened.

Reimplemented in PWAVFile.

virtual BOOL PFile::Open OpenMode  mode = ReadWrite,
int  opts = ModeDefault
[virtual]
 

Open the current file in the specified mode and with the specified options. If the file object already has an open file then it is closed.

If there has not been a filename attached to the file object (via #SetFilePath()#, the #name# parameter or a previous open) then a new unique temporary filename is generated.

Returns:
TRUE if the file was successfully opened.

Reimplemented in PWAVFile.

virtual BOOL PFile::Read void *  buf,
PINDEX  len
[virtual]
 

Low level read from the file channel. The read timeout is ignored for file I/O. The GetLastReadCount() function returns the actual number of bytes read.

The GetErrorCode() function should be consulted after Read() returns FALSE to determine what caused the failure.

Returns:
TRUE indicates that at least one character was read from the channel. FALSE means no bytes were read due to timeout or some other I/O error.
Parameters:
len  Pointer to a block of memory to receive the read bytes. Maximum number of bytes to read into the buffer.

Reimplemented from PChannel.

Reimplemented in PMemoryFile, and PWAVFile.

PINLINE BOOL PFile::Remove BOOL  force = FALSE  ) 
 

Delete the current file. If #force# is FALSE and the file is protected against being deleted then the function fails. If #force# is TRUE then the protection is ignored. What constitutes file deletion protection is platform dependent, eg on DOS is the Read Only attribute and on a Novell network it is a Delete trustee right. Some protection may not be able to overridden with the #force# parameter at all, eg on a Unix system and you are not the owner of the file.

Returns:
TRUE if the file was deleted.

BOOL PFile::Remove const PFilePath name,
BOOL  force = FALSE
[static]
 

Delete the specified file. If #force# is FALSE and the file is protected against being deleted then the function fails. If #force# is TRUE then the protection is ignored. What constitutes file deletion protection is platform dependent, eg on DOS is the Read Only attribute and on a Novell network it is a Delete trustee right. Some protection may not be able to overridden with the #force# parameter at all, eg on a Unix system and you are not the owner of the file.

Returns:
TRUE if the file was deleted.

BOOL PFile::Rename const PString newname,
BOOL  force = FALSE
 

Change the current files name. This does not move the file in the directory hierarchy, it only changes the name of the directory entry.

The #newname# parameter must consist only of the file name part, as returned by the #PFilePath::GetFileName()# function. Any other file path parts will cause an error.

The first form uses the file path specification associated with the instance of the object. The name within the instance is changed to the new name if the function succeeds. The second static function uses an arbitrary file specified by name.

Returns:
TRUE if the file was renamed.
Parameters:
force  New name for the file. Delete file if a destination exists with the same name.

BOOL PFile::Rename const PFilePath oldname,
const PString newname,
BOOL  force = FALSE
[static]
 

Change the specified files name. This does not move the file in the directory hierarchy, it only changes the name of the directory entry.

The #newname# parameter must consist only of the file name part, as returned by the #PFilePath::GetFileName()# function. Any other file path parts will cause an error.

The first form uses the file path specification associated with the instance of the object. The name within the instance is changed to the new name if the function succeeds. The second static function uses an arbitrary file specified by name.

Returns:
TRUE if the file was renamed.
Parameters:
newname  Old name of the file.
force  New name for the file. Delete file if a destination exists with the same name.

void PFile::SetFilePath const PString path  ) 
 

Set the full path name of the file. The PFilePath# object describes the full file name specification for the particular platform.

Parameters:
path  New file path.

virtual BOOL PFile::SetLength off_t  len  )  [virtual]
 

Set the size of the file, padding with 0 bytes if it would require expanding the file, or truncating it if being made shorter.

Returns:
TRUE if the file size was changed to the length specified.

Reimplemented in PMemoryFile.

PINLINE BOOL PFile::SetPermissions int  permissions  ) 
 

Set permissions on the current file.

Returns:
TRUE if the file was renamed.

BOOL PFile::SetPermissions const PFilePath name,
int  permissions
[static]
 

Set permissions on the specified file.

Returns:
TRUE if the file was renamed.

virtual BOOL PFile::SetPosition off_t  pos,
FilePositionOrigin  origin = Start
[virtual]
 

Set the current active position in the file for the next read or write operation. The #pos# variable is a signed number which is added to the specified origin. For #origin == PFile::Start# only positive values for #pos# are meaningful. For #origin == PFile::End# only negative values for #pos# are meaningful.

Returns:
TRUE if the new file position was set.
Parameters:
origin  New position to set. Origin for position change.

Reimplemented in PMemoryFile, and PWAVFile.

virtual BOOL PFile::Write const void *  buf,
PINDEX  len
[virtual]
 

Low level write to the file channel. The write timeout is ignored for file I/O. The GetLastWriteCount() function returns the actual number of bytes written.

The GetErrorCode() function should be consulted after Write() returns FALSE to determine what caused the failure.

Returns:
TRUE if at least len bytes were written to the channel.
Parameters:
len  Pointer to a block of memory to write. Number of bytes to write.

Reimplemented from PChannel.

Reimplemented in PMemoryFile, and PWAVFile.


Member Data Documentation

PFilePath PFile::path [protected]
 

The fully qualified path name for the file.

BOOL PFile::removeOnClose [protected]
 

File is to be removed when closed.


The documentation for this class was generated from the following files:
Generated on Sat Jul 24 15:35:58 2004 for PWLib by doxygen 1.3.7