FileBackedBuffer Class Reference

#include <file_backed_buffer.h>

Inheritance diagram for FileBackedBuffer:

Collaboration diagram for FileBackedBuffer:

Public Member Functions
	~FileBackedBuffer ()
void	Append (const void *source, uint64_t len)
void	Commit ()
int64_t	Data (void **ptr, int64_t len, uint64_t pos)
int64_t	Read (void *ptr, int64_t len)
int64_t	ReadP (void *ptr, int64_t len, uint64_t pos)
void	Rewind ()
uint64_t	GetSize () const

Static Public Member Functions
static FileBackedBuffer *	Create (uint64_t in_memory_threshold, const std::string &tmp_dir="/tmp/")

Private Types
enum	{ kWriteState = 0, kReadState }
enum	{ kMemoryMode = 0, kFileMode }

Private Member Functions
	FRIEND_TEST (T_FileBackedBuffer, SimpleWriteAndRead)
	FRIEND_TEST (T_FileBackedBuffer, EmptyBuffer)
	FRIEND_TEST (T_FileBackedBuffer, EmptyWrite)
	FRIEND_TEST (T_FileBackedBuffer, StraightToFile)
	FRIEND_TEST (T_FileBackedBuffer, OnlyInMemory)
	FileBackedBuffer (uint64_t in_memory_threshold, const std::string &tmp_dir)
void	SaveToFile ()
Private Member Functions inherited from SingleCopy
	SingleCopy ()

Private Attributes
const uint64_t	in_memory_threshold_
const std::string	tmp_dir_
enum FileBackedBuffer:: { ... }	state_
enum FileBackedBuffer:: { ... }	mode_
uint64_t	size_
unsigned char *	buf_
uint64_t	pos_
FILE *	fp_
std::string	file_path_
MemoryMappedFile *	mmapped_

Detailed Description

This file is part of the CernVM File System. FileBackedBuffer is a class for smart data writing and reading. It represents a buffer that is in a first step filled with data and, once all data has been written, it can be read back out.

It works in 2 modes: memory mode and file mode. It first starts working in memory mode, but as soon as the buffer size reaches a configurable threshold, it writes all data into a temporary file, freeing up the occupied memory. From that point, all further data are written directly into the file.

Reading is done straight from memory or using mmap, depending on the current mode of operation.

Method call timeline:

1. Create
2. Append
3. Commit
4. Data/Read/ReadP, Rewind

Definition at line 37 of file file_backed_buffer.h.

Member Enumeration Documentation

anonymous enum

private

Enumerator
kWriteState
kReadState

Definition at line 65 of file file_backed_buffer.h.

anonymous enum

private

Enumerator
kMemoryMode
kFileMode

Definition at line 70 of file file_backed_buffer.h.

Constructor & Destructor Documentation

FileBackedBuffer::~FileBackedBuffer

(

)

Definition at line 37 of file file_backed_buffer.cc.

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FileBackedBuffer::FileBackedBuffer ( uint64_t  in_memory_threshold, const std::string &  tmp_dir  )

private

Definition at line 22 of file file_backed_buffer.cc.

Referenced by Create().

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Member Function Documentation

void FileBackedBuffer::Append	(	const void *	source,
		uint64_t	len
	)

Definition at line 57 of file file_backed_buffer.cc.

Referenced by upload::S3Uploader::DoUpload().

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void FileBackedBuffer::Commit

(

)

Definition at line 98 of file file_backed_buffer.cc.

Referenced by upload::S3Uploader::DoUpload().

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FileBackedBuffer * FileBackedBuffer::Create ( uint64_t  in_memory_threshold, const std::string &  tmp_dir = "/tmp/"  )

static

This file is part of the CernVM File System.

Definition at line 16 of file file_backed_buffer.cc.

Referenced by upload::S3Uploader::CreateJobInfo(), upload::S3Uploader::DoUpload(), and upload::S3StreamHandle::S3StreamHandle().

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int64_t FileBackedBuffer::Data	(	void **	ptr,
		int64_t	len,
		uint64_t	pos
	)

Definition at line 121 of file file_backed_buffer.cc.

Referenced by ReadP().

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FileBackedBuffer::FRIEND_TEST ( T_FileBackedBuffer  , SimpleWriteAndRead    )

private

FileBackedBuffer::FRIEND_TEST ( T_FileBackedBuffer  , EmptyBuffer    )

private

FileBackedBuffer::FRIEND_TEST ( T_FileBackedBuffer  , EmptyWrite    )

private

FileBackedBuffer::FRIEND_TEST ( T_FileBackedBuffer  , StraightToFile    )

private

FileBackedBuffer::FRIEND_TEST ( T_FileBackedBuffer  , OnlyInMemory    )

private

uint64_t FileBackedBuffer::GetSize

(

)

const

Definition at line 154 of file file_backed_buffer.cc.

int64_t FileBackedBuffer::Read	(	void *	ptr,
		int64_t	len
	)

Definition at line 136 of file file_backed_buffer.cc.

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int64_t FileBackedBuffer::ReadP	(	void *	ptr,
		int64_t	len,
		uint64_t	pos
	)

Definition at line 142 of file file_backed_buffer.cc.

Referenced by Read().

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void FileBackedBuffer::Rewind

(

)

Definition at line 149 of file file_backed_buffer.cc.

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void FileBackedBuffer::SaveToFile ( )

private

Definition at line 161 of file file_backed_buffer.cc.

Referenced by Append().

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Member Data Documentation

unsigned char* FileBackedBuffer::buf_

private

Definition at line 77 of file file_backed_buffer.h.

Referenced by Append(), Commit(), Data(), SaveToFile(), and ~FileBackedBuffer().

std::string FileBackedBuffer::file_path_

private

Definition at line 83 of file file_backed_buffer.h.

Referenced by Append(), Commit(), SaveToFile(), and ~FileBackedBuffer().

FILE* FileBackedBuffer::fp_

private

Definition at line 81 of file file_backed_buffer.h.

Referenced by Append(), Commit(), SaveToFile(), and ~FileBackedBuffer().

const uint64_t FileBackedBuffer::in_memory_threshold_

private

Definition at line 62 of file file_backed_buffer.h.

Referenced by Append().

MemoryMappedFile* FileBackedBuffer::mmapped_

private

Definition at line 85 of file file_backed_buffer.h.

Referenced by Commit(), Data(), and ~FileBackedBuffer().

enum { ... } FileBackedBuffer::mode_

Referenced by Append(), Commit(), Data(), GetSize(), SaveToFile(), and ~FileBackedBuffer().

uint64_t FileBackedBuffer::pos_

private

Definition at line 79 of file file_backed_buffer.h.

Referenced by Append(), Commit(), GetSize(), Read(), Rewind(), and SaveToFile().

uint64_t FileBackedBuffer::size_

private

Definition at line 75 of file file_backed_buffer.h.

Referenced by Append(), Commit(), Data(), GetSize(), and SaveToFile().

enum { ... } FileBackedBuffer::state_

Referenced by Append(), Commit(), Data(), GetSize(), Rewind(), SaveToFile(), and ~FileBackedBuffer().

const std::string FileBackedBuffer::tmp_dir_

private

Definition at line 63 of file file_backed_buffer.h.

Referenced by SaveToFile().

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

• /home/sftnight/jenkins/workspace/CvmfsDoxygen/label/docker-x86_64/cvmfs/cvmfs/util/file_backed_buffer.h
• /home/sftnight/jenkins/workspace/CvmfsDoxygen/label/docker-x86_64/cvmfs/cvmfs/util/file_backed_buffer.cc