taco::File Class Reference

Represents an open virtual file managed by the FileManager. More...

#include <storage/FileManager.h>

Public Member Functions
	~File ()
	Destructor. More...
void	Close ()
	Closes the file. More...
constexpr bool	IsOpen () const noexcept
void	ReadPage (PageNumber pid, char *buf) const
	Reads a page at the specified page number. More...
void	WritePage (PageNumber pid, const char *buf)
	Writes a page at the specified page number. More...
PageNumber	AllocatePage ()
	Allocates a new page in the file and returns it page number. More...
BufferId	AllocatePage (LatchMode mode)
	Allocates a new page in the file and returns a valid buffer ID where is pinned. More...
void	FreePage (BufferId bufid)
	Returns a page that belongs to this file to its free page list. More...
void	FreePage (ScopedBufferId &bufid)
	Same as FreePage(BufferId) but prevents double free. More...
PageNumber	GetFirstPageNumber () const
	Returns the first page's PID. More...
PageNumber	GetLastPageNumber () const
	Returns the last page's PID. More...
void	Flush ()
	Flushes bytes already written to the file. More...
constexpr FileId	GetFileId () const
constexpr bool	IsMainFile () const
constexpr bool	IsTmpFile () const
constexpr bool	IsWalFile () const

Private Member Functions
	File ()
uint64_t	AllocatePageImpl (bool need_latch, LatchMode mode)
	The actual implementation of AllocatePage(). More...

Private Attributes
FileId	m_fileid
PageNumber	m_meta_pid
std::unique_ptr< FSFile >	m_fsfile

Friends
class	FileManager

Detailed Description

Represents an open virtual file managed by the FileManager.

Constructor & Destructor Documentation

~File()

taco::File::~File

(

)

Destructor.

Automatically calls Close().

File()

taco::File::File ( )

inlineprivate

Member Function Documentation

AllocatePage() [1/2]

PageNumber taco::File::AllocatePage ( )

inline

Allocates a new page in the file and returns it page number.

If this is a main file, the new page is not pinned in the buffer maanger.

If this is temporary file, this function simply extends the file by 1 page.

WAL files are not supported at the moment.

AllocatePage() [2/2]

BufferId taco::File::AllocatePage ( LatchMode  mode )

inline

Allocates a new page in the file and returns a valid buffer ID where is pinned.

You may ignore the latch mode parameter and pass any value to use this function.

It is an error if this overload is called on a TMP or WAL file.

AllocatePageImpl()

uint64_t taco::File::AllocatePageImpl ( bool  need_latch, LatchMode  mode  )

private

The actual implementation of AllocatePage().

Close()

void taco::File::Close

(

)

Closes the file.

It never fails.

Flush()

void taco::File::Flush

(

)

Flushes bytes already written to the file.

Note that this may not be called on a main file, where Flush() must go through file manager.

This may be called on a temporary file.

WAL files are not supported at the moment.

FreePage() [1/2]

void taco::File::FreePage

(

BufferId

bufid

)

Returns a page that belongs to this file to its free page list.

The parameter bufid should be a valid buffer ID where the page to return is pinned.

After the call, the pin on the page is dropped.

It is an error if it is called on a TMP or WAL file.

FreePage() [2/2]

void taco::File::FreePage ( ScopedBufferId &  bufid )

inline

Same as FreePage(BufferId) but prevents double free.

It is an error if it is called on a TMP or WAL file.

GetFileId()

constexpr FileId taco::File::GetFileId ( ) const

inlineconstexpr

GetFirstPageNumber()

PageNumber taco::File::GetFirstPageNumber

(

)

const

Returns the first page's PID.

The first page's PID never changes so it is not possible that there is any page before the returned page.

If this is a main file, this is the first page in the linked list.

If this is a temporary file, this is always 0 (note that temporary file has a different page number space than the main files).

WAL files are not supported at the moment.

GetLastPageNumber()

PageNumber taco::File::GetLastPageNumber

(

)

const

Returns the last page's PID.

Note that concurrent threads may still append new pages into this file, so the returned PID might not be the last by the time the page is read.

If this is a main file, this is the last page in the linked list.

If this is a temporary file, this is the last page number (file size / PAGE_SIZE - 1) (note that temporary file has a different page number space than the main files).

WAL files are not supported at the moment.

IsMainFile()

constexpr bool taco::File::IsMainFile ( ) const

inlineconstexpr

IsOpen()

constexpr bool taco::File::IsOpen ( ) const

inlineconstexprnoexcept

IsTmpFile()

constexpr bool taco::File::IsTmpFile ( ) const

inlineconstexpr

IsWalFile()

constexpr bool taco::File::IsWalFile ( ) const

inlineconstexpr

ReadPage()

void taco::File::ReadPage	(	PageNumber	pid,
		char *	buf
	)		const

Reads a page at the specified page number.

If this is a main file, this function will simply forward the call to FileManager::ReadPage().

If this is a temporary file, this function will directly read the page from the underlying FSFile.

WAL files are not supported at the moment.

WritePage()

void taco::File::WritePage	(	PageNumber	pid,
		const char *	buf
	)

Writes a page at the specified page number.

If this is a main file, this function will simply forward the call to FileManager::WritePage().

If this is a temporary file, this function will directly write the page into the underlying FSFile.

WAL files are not supported at the moment.

Friends And Related Function Documentation

FileManager

friend class FileManager

friend

Member Data Documentation

m_fileid

FileId taco::File::m_fileid

private

m_fsfile

std::unique_ptr<FSFile> taco::File::m_fsfile

private

m_meta_pid

PageNumber taco::File::m_meta_pid

private

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

• storage/FileManager.h
• storage/FileManager.cpp