ibis::fileManager::roFile Class Reference

This class manages content of a whole (read-only) file. More...

#include <fileManager.h>

Inheritance diagram for ibis::fileManager::roFile:

Public Member Functions
virtual void	beginUse ()
	Start using a file. Increments the active reference.
int	disconnectFile ()
	Disconnect the storage object from the file. More...
virtual void	endUse ()
	Stop using a file. Decrement the active reference count.
virtual bool	isFileMap () const
	Is the storage a file map ?
virtual void	printStatus (std::ostream &out) const
	Print information about the storage object to the specified output stream. More...
void	read (const char *file)
Public Member Functions inherited from ibis::fileManager::storage
char *	begin ()
	Starting address of the storage object.
const char *	begin () const
	Starting address of the storage object.
size_t	bytes () const
	Return the number of bytes contained in the object.
void	copy (const storage &rhs)
	Copy function. Make an in-meory copy following the copy-and-swap idiom.
bool	empty () const
	Is the storage object empty?
const char *	end () const
	Ending address of the storage object.
void	enlarge (size_t nelm=0)
	Enlarge the current storage object. More...
const char *	filename () const
	Pointer to the file name supporting this storage object. More...
unsigned	inUse () const
	Number of current accesses to this object.
storage &	operator= (const storage &rhs)
	Assignment operator. More...
char	operator[] (size_t i) const
	Unchecked index operator. Returns the character at position i.
unsigned	pastUse () const
	Number of past accesses to this object.
off_t	read (const char *fname, const off_t begin, const off_t end)
	Read a part of a file. More...
off_t	read (const int fdes, const off_t begin, const off_t end)
	Read part of a open file [begin, end). Return the number of bytes read.
size_t	size () const
	Return the size (bytes) of the object.
	storage ()
	Constructor. Allocate no real storage.
	storage (size_t n)
	Constructor. More...
	storage (const char *fname, const off_t begin, const off_t end)
	Constructor. Read part of a file from [begin, end).
	storage (const int fdes, const off_t begin, const off_t end)
	Constructor. Read part of a open file, from [begin, end). The file.
	storage (const char *begin, const char *end)
	Copy constructor. Copy the values between begin and end [begin, end).
	storage (char *addr, size_t num)
	Wrap user provided memory into a storage object. More...
	storage (const storage &rhs)
	Copy constructor. Make an in-memory copy.
void	swap (storage &rhs) throw ()
	Swap the content of the storage objects. More...
void	write (const char *file) const

Protected Member Functions
virtual void	clear ()
	Freeing the storage allocated. More...
void	doRead (const char *file)
	Read the content of a file into memory.
void	doRead (const char *file, off_t b, off_t e)
	Read a portion of a file into memory. More...
void	printBody (std::ostream &out) const
virtual void *	release ()
	Release the control of the memory to the caller as a raw pointer. More...
	roFile ()
	Constructor.
float	score () const
	The function assigns a score to a file. More...

Friends
class	ibis::fileManager

Additional Inherited Members
Protected Attributes inherited from ibis::fileManager::storage
char *	m_begin
	Beginning of the storage.
char *	m_end
	End of the storage.
unsigned	nacc
	Number of accesses in the past.
char *	name
	Name of the file. NULL (0) if no file is involved.
ibis::util::sharedInt32	nref
	Number of (active) references to this storage.

Detailed Description

This class manages content of a whole (read-only) file.

It inherits the basic information stored in fileManager::storage and is intended to process read-only files.

Note

This class intends to hold a piece of memory managed by ibis::fileManager. If an object of this type is acquired through ibis::fileManager::getFile, the ownership of the object belongs to the file manager, therefore the caller should not delete the object.

Member Function Documentation

void ibis::fileManager::roFile::clear ( )

protectedvirtual

Freeing the storage allocated.

It will only proceed if there is no active reference to it.

Reimplemented from ibis::fileManager::storage.

int ibis::fileManager::roFile::disconnectFile

(

)

Disconnect the storage object from the file.

This can only be done for a file whose content has been read into memory, not for a mapped file.

It returns 0 or a positive value to indicate success, otherwise it returns a negative number to indicate error.

References ibis::fileManager::instance(), and ibis::fileManager::unrecordFile().

void ibis::fileManager::roFile::doRead ( const char *  file, off_t  b, off_t  e  )

protected

Read a portion of a file into memory.

Do NOT record the name of the file. This is different from the one that read the whole file which automatically records the name of the file.

References ibis::fileManager::instance(), ibis::util::read(), ibis::fileManager::recordPages(), and UnixOpen.

void ibis::fileManager::roFile::printStatus ( std::ostream &  out ) const

virtual

Print information about the storage object to the specified output stream.

Reimplemented from ibis::fileManager::storage.

Referenced by ibis::fileManager::getFile(), and ibis::fileManager::tryGetFile().

virtual void* ibis::fileManager::roFile::release ( )

inlineprotectedvirtual

Release the control of the memory to the caller as a raw pointer.

The caller is to take control of memory and responsible for freeing it after use.

It can only proceed if there is no other accesses to this object.

Reimplemented from ibis::fileManager::storage.

float ibis::fileManager::roFile::score ( ) const

inlineprotected

The function assigns a score to a file.

It is used by ibis::fileManager::unload to determine what files to remove. Files with the smallest scores are the target for removal.

References ibis::fileManager::storage::nacc, and ibis::fileManager::storage::size().

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The documentation for this class was generated from the following files:

• fileManager.h
• fileManager.cpp