NAME
RandomFile - The purpose of this class is to define a base class for low level random file access that is portable between Win32 and Posix systems. Portable random disk file access.
SYNOPSIS
#include <file.h>
Inherits Mutex, and File.
Inherited by MappedFile, SharedFile, and ThreadFile.
Public Methods
virtual ~RandomFile ()
Destroy a random access file or it's derived class. bool initial (void)
This method should be called right after a RandomFile derived object has been created. off_t getCapacity (void)
Get current file capacity. virtual Error restart (void)
This method is commonly used to close and re-open an existing database. Error getErrorNumber (void)
Return current error id. char * getErrorString (void)
Return current error string. bool operator! (void)
Protected Methods
RandomFile ()
Create an unopened random access file. RandomFile (const RandomFile &rf)
Default copy constructor. Error error (Error errid, char *errstr=NULL)
Post an error event. Error error (char *errstr)
Post an extended string error message. void setError (bool enable)
Used to enable or disable throwing of exceptions on errors. Error setCompletion (Complete mode)
Used to set file completion modes. void setTemporary (bool enable)
Used to set the temporary attribute for the file. virtual Attr initialize (void)
This method is used to initialize a newly created file as indicated by the 'initial' flag. void final (void)
Close the file.
Protected Attributes
int fd
Access access
char * pathname
struct {
unsigned count: 16
bool thrown: 1
bool initial: 1
bool immediate: 1
bool temp: 1
} flags
Related Functions
(Note that these are not member functions.) bool isDir (const char *path)
bool isFile (const char *path)
bool isDevice (const char *path)
bool canAccess (const char *path)
bool canModify (const char *path)
DETAILED DESCRIPTION
The purpose of this class is to define a base class for low level random file access that is portable between Win32 and Posix systems. Portable random disk file access.
This class is a foundation both for optimized thread shared and traditional locked file access that is commonly used to build database services, rather than the standard C++ streaming file classes.
Author: David Sugar <[email protected]>
CONSTRUCTOR & DESTRUCTOR DOCUMENTATION
RandomFile::RandomFile () [protected]
Create an unopened random access file.
RandomFile::RandomFile (const RandomFile & rf) [protected]
Default copy constructor.
virtual RandomFile::~RandomFile () [inline, virtual]
Destroy a random access file or it's derived class.
MEMBER FUNCTION DOCUMENTATION
Error RandomFile::error (char * errstr) [inline, protected]
Post an extended string error message.
Returns: errExtended.
Parameters:
- errstr
-
error string.
Error RandomFile::error (Error errid, char * errstr = NULL) [protected]
Post an error event.
Returns: error code.
Parameters:
- errid
-
error code.
- errstr
-
error message string.
void RandomFile::final (void) [protected]
Close the file.
off_t RandomFile::getCapacity (void)
Get current file capacity.
Returns: total file size.
Error RandomFile::getErrorNumber (void) [inline]
Return current error id.
Returns: last error identifier set.
char* RandomFile::getErrorString (void) [inline]
Return current error string.
Returns: last error string set.
bool RandomFile::initial (void)
This method should be called right after a RandomFile derived object has been created.
This method will invoke initialize if the object is newly created, and set file access permissions appropriately.
Returns: true if file had to be initialized.
virtual Attr RandomFile::initialize (void) [inline, protected, virtual]
This method is used to initialize a newly created file as indicated by the 'initial' flag.
This method also returns the file access permissions that should be associated with the file. This method should never be called directly, but is instead used to impliment the 'Initial' method. Typically one would use this to build an empty database shell when a previously empty database file is created.
Returns: access, or attrInvalid if should be removed.
bool RandomFile::operator! (void)
virtual Error RandomFile::restart (void) [inline, virtual]
This method is commonly used to close and re-open an existing database.
This may be used when the database has been unlinked and an external process provides a new one to use.
Reimplemented in ThreadFile, and SharedFile.
Error RandomFile::setCompletion (Complete mode) [protected]
Used to set file completion modes.
Returns: errSuccess if okay.
Parameters:
- mode
-
completion mode.
Todo:
implement in win32
void RandomFile::setError (bool enable) [inline, protected]
Used to enable or disable throwing of exceptions on errors.
Parameters:
- enable
-
true if errors will be thrown.
void RandomFile::setTemporary (bool enable) [inline, protected]
Used to set the temporary attribute for the file.
Temporary files are automatically deleted when closed.
Parameters:
- enable
-
true for marking as temporary.
FRIENDS AND RELATED FUNCTION DOCUMENTATION
bool canAccess (const char * path) [related]
bool canModify (const char * path) [related]
bool isDevice (const char * path) [related]
bool isDir (const char * path) [related]
bool isFile (const char * path) [related]
MEMBER DATA DOCUMENTATION
Access RandomFile::access [protected]
unsigned RandomFile::count [protected]
int RandomFile::fd [protected]
struct { ... } RandomFile::flags [protected]
bool RandomFile::immediate [protected]
bool RandomFile::initial [protected]
char* RandomFile::pathname [protected]
bool RandomFile::temp [protected]
bool RandomFile::thrown [protected]
AUTHOR
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