BufferManager Class Reference

Buffer manager is an abstraction of memory on computer for modules at higher level. More...

#include <buffer_manager.h>

Public Member Functions
	BufferManager ()
	Construct a new Buffer Manager:: Buffer Manager object. More...
	BufferManager (int frame_size)
	~BufferManager ()
	Destroy the Buffer Manager:: Buffer Manager object. More...
char *	getPage (const std::string &file_name, int block_id)
	获取一页 More...
char *	getPage (const std::string &file_name, int block_id, pageId_t &pageId)
void	modifyPage (int page_id)
	标记页是否被修改 More...
void	pinPage (int page_id)
	钉住一页 More...
int	unpinPage (int page_id)
	解钉一次 More...
int	flushPage (pageId_t page_id)
	核心函数之一。内存和磁盘交互的接口。 More...
int	getPageId (const std::string &file_name, int block_id)
	简单遍历获取页号 More...
void	removeFile (const std::string &path)
int	getBlockNum (const std::string &fileName)
	获取文件块数 More...

Static Public Member Functions
static size_t	getFileSize (std::string file_name)
static bool	FileExists (const std::string &path)
static void	createEmptyFile (const std::string &path)

Detailed Description

Buffer manager is an abstraction of memory on computer for modules at higher level.

Definition at line 69 of file buffer_manager.h.

Constructor & Destructor Documentation

BufferManager()

BufferManager::BufferManager

(

)

Construct a new Buffer Manager:: Buffer Manager object.

Definition at line 96 of file buffer_manager.cpp.

~BufferManager()

BufferManager::~BufferManager

(

)

Destroy the Buffer Manager:: Buffer Manager object.

Definition at line 108 of file buffer_manager.cpp.

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Member Function Documentation

flushPage()

int BufferManager::flushPage

(

pageId_t

page_id

)

核心函数之一。内存和磁盘交互的接口。

将对应内存页写入对应文件的对应块。

Parameters

page_id	块ID
file_name	文件名
block_id	页ID

Returns

int 成功返回0，否则返回-1

Definition at line 227 of file buffer_manager.cpp.

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getBlockNum()

int BufferManager::getBlockNum

(

const std::string &

file_name

)

获取文件块数

Parameters

file_name

文件名

Returns

int 块数

Definition at line 270 of file buffer_manager.cpp.

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getPage()

char * BufferManager::getPage	(	const std::string &	file_name,
		int	block_id
	)

获取一页

通过页号得到页的句柄(一个页的头地址)

Parameters

file_name	文件名
block_id	块ID

Returns

char* 一个页的句柄

Definition at line 130 of file buffer_manager.cpp.

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getPageId()

pageId_t BufferManager::getPageId	(	const std::string &	file_name,
		int	block_id
	)

简单遍历获取页号

获取对应文件的对应块在内存中的页号，没有找到返回-1

Parameters

file_name	文件名
block_id	块ID

Returns

int 找到返回对应页ID，否则返回-1

Definition at line 258 of file buffer_manager.cpp.

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modifyPage()

void BufferManager::modifyPage

(

int

page_id

)

标记页是否被修改

标记page_id所对应的页已经被修改

Parameters

page_id

页ID

Definition at line 155 of file buffer_manager.cpp.

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pinPage()

void BufferManager::pinPage

(

int

page_id

)

钉住一页

钉住一个页

Parameters

page_id

页ID

Definition at line 163 of file buffer_manager.cpp.

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unpinPage()

int BufferManager::unpinPage

(

int

page_id

)

解钉一次

解除一个页的钉住状态(需要注意的是一个页可能被多次钉住，该函数只能解除一次),如果对应页的pin_count_为0，则返回-1

Parameters

page_id

页ID

Returns

int 该页未被钉住返回-1，否则返回0

Definition at line 173 of file buffer_manager.cpp.

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

• src/include/buffer/buffer_manager.h
• src/buffer/buffer_manager.cpp