MappedRegion Class Reference

#include "MappedRegion.h"

Public Member Functions
	MappedRegion ()=default
	MappedRegion (const MappedRegion &)=delete
MappedRegion &	operator= (const MappedRegion &)=delete
std::size_t	openFile (const char *filename, bool read_only)
	Open (creating if absent) the backing file.
void	resizeFile (std::size_t length)
	Set the backing file's size.
void	map (std::size_t length)
	Establish the initial region of length bytes over the file.
void	remap (std::size_t new_length)
	Grow the region to new_length, preserving existing content.
void	sync ()
	Flush the region to the backing file (no-op when read-only).
void	close ()
	Write back (if writable) and release the region and file.
void *	base () const
std::size_t	length () const

Private Attributes
int	fd_ = -1
	Backing file descriptor.
void *	base_ = nullptr
	Base of the mapped region / heap buffer.
std::size_t	length_ = 0
	Current region length in bytes.
bool	read_only_ = false
	Opened read-only (no write-back).

Detailed Description

Definition at line 41 of file MappedRegion.h.

Constructor & Destructor Documentation

MappedRegion() [1/2]

MappedRegion::MappedRegion ( )

default

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MappedRegion() [2/2]

MappedRegion::MappedRegion ( const MappedRegion & )

delete

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Member Function Documentation

base()

void * MappedRegion::base ( ) const

inline

Definition at line 156 of file MappedRegion.h.

close()

void MappedRegion::close ( )

inline

Write back (if writable) and release the region and file.

Definition at line 140 of file MappedRegion.h.

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length()

std::size_t MappedRegion::length ( ) const

inline

Definition at line 157 of file MappedRegion.h.

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map()

void MappedRegion::map ( std::size_t length )

inline

Establish the initial region of length bytes over the file.

Definition at line 86 of file MappedRegion.h.

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openFile()

std::size_t MappedRegion::openFile ( const char * filename, bool read_only )

inline

Open (creating if absent) the backing file.

Returns

The file's current size in bytes (0 if newly created).

Definition at line 56 of file MappedRegion.h.

operator=()

MappedRegion & MappedRegion::operator= ( const MappedRegion & )

delete

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remap()

void MappedRegion::remap ( std::size_t new_length )

inline

Grow the region to new_length, preserving existing content.

Definition at line 106 of file MappedRegion.h.

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resizeFile()

void MappedRegion::resizeFile ( std::size_t length )

inline

Set the backing file's size.

The shared-mmap backend must pre-size the file (mmap maps file-backed pages). The heap-buffer backend does not: it allocates the buffer and sync() extends the file with pwrite. Crucially, leaving the file unsized until the first sync() means a fresh file that is never synced (e.g. a backend that aborts before write-back) stays empty on disk and is re-initialised cleanly on reopen, rather than persisting as a full-size, never-written file whose zero header fails magic validation.

Definition at line 76 of file MappedRegion.h.

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sync()

void MappedRegion::sync ( )

inline

Flush the region to the backing file (no-op when read-only).

Definition at line 128 of file MappedRegion.h.

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Member Data Documentation

base_

void* MappedRegion::base_ = nullptr

private

Base of the mapped region / heap buffer.

Definition at line 43 of file MappedRegion.h.

fd_

int MappedRegion::fd_ = -1

private

Backing file descriptor.

Definition at line 42 of file MappedRegion.h.

length_

std::size_t MappedRegion::length_ = 0

private

Current region length in bytes.

Definition at line 44 of file MappedRegion.h.

read_only_

bool MappedRegion::read_only_ = false

private

Opened read-only (no write-back).

Definition at line 45 of file MappedRegion.h.

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

• /home/senellar/git/software/provsql/src/MappedRegion.h