Directly read file served from joedb_server. More...

#include <joedb/concurrency/Server_File.h>

Inheritance diagram for joedb::Server_File:

[legend]

Collaboration diagram for joedb::Server_File:

[legend]

Public Member Functions
	Server_File (const Connector &connector, Logger &logger=Logger::dummy_logger)

int64_t	handshake (const Readonly_Journal &client_journal, Content_Check content_check) override
	Called during Client construction.

int64_t	pull (Lock_Action lock_action, Data_Transfer data_transfer, Writable_Journal &client_journal, std::chrono::milliseconds wait) override
	Pull from the connection.

int64_t	push (const Readonly_Journal &client_journal, int64_t server_position, int64_t until_position, Unlock_Action unlock_action) override
	Push new data to the connection.

size_t	pread (char *data, size_t size, int64_t offset) const override
	Read a range of bytes.

void	pwrite (const char *data, size_t size, int64_t offset) override
	Write a range of bytes. Extend file size if necessary.

int64_t	get_size () const override
	Get the size of the file, or -1 if it is unknown.

Public Member Functions inherited from joedb::Robust_Connection
	Robust_Connection (const Connector &connector, Logger &logger)

size_t	pread (char *data, size_t size, int64_t offset) const

void	unlock () override
	Unlock the connection.

bool	is_pullonly () const override

Public Member Functions inherited from joedb::Connection
virtual	~Connection ()

Public Member Functions inherited from joedb::Abstract_File
	Abstract_File (Open_Mode mode)

bool	is_shared () const noexcept

bool	is_readonly () const noexcept

Open_Mode	get_mode () const noexcept

void	full_pread (char *data, size_t size, int64_t offset) const
	Fill the buffer, or throw if the end of the file is reached.

virtual void	sync ()
	Write data durably (including file-size change)

virtual void	datasync ()
	Write data durably (no file-size change)

virtual void	shared_lock (int64_t start, int64_t size)
	Lock a range of bytes for reading (prevents writes, not reads)

virtual void	exclusive_lock (int64_t start, int64_t size)
	Lock a range of bytes for writing (prevents both writes and reads)

virtual void	unlock (int64_t start, int64_t size) noexcept
	Remove a lock. The range should match the range of a corresponding lock.

void	exclusive_lock_tail ()

void	unlock_tail () noexcept

void	exclusive_lock_head ()

void	shared_lock_head ()

void	unlock_head () noexcept

std::string	read_blob (Blob blob, int64_t max_size=-1) const

virtual void	copy_to (Abstract_File &destination, int64_t start, int64_t size) const

virtual bool	equal_to (const Abstract_File &destination, int64_t from, int64_t until) const

void	copy_to (Abstract_File &destination) const

virtual	~Abstract_File ()=default

Additional Inherited Members
Static Public Member Functions inherited from joedb::Abstract_File
static void	reading_past_end_of_file ()

Static Public Attributes inherited from joedb::Connection
static Connection	dummy
	Since this class has no internal state, this global variable can be used instead of creating an instance.

Protected Member Functions inherited from joedb::Robust_Connection
void	reconnect (const std::exception *e) const

template<typename F >
auto	try_until_success (const F &f) const

Protected Member Functions inherited from joedb::Connection
	Connection ()=default

Protected Member Functions inherited from joedb::Abstract_File
void	make_readonly ()

void	make_writable ()

Static Protected Member Functions inherited from joedb::Connection
static void	content_mismatch ()
	Called by handshake when the file and the connection do not match.

Protected Attributes inherited from joedb::Robust_Connection
std::unique_ptr< Server_Connection >	connection

Static Protected Attributes inherited from joedb::Abstract_File
static constexpr int64_t	last_position = (1ULL << 63) - 1

Detailed Description

This class allows reading a remote file via the joedb network protocol. It is convenient for reading blobs from a large remote database without having to download a local replica. This file can also be written to: the head and tail of the file are stored in RAM locally, and can be pushed to the remote server if used in a client.

#include "joedb/concurrency/Local_Connector.h"
#include "joedb/concurrency/Server_File.h"
#include "joedb/concurrency/Writable_Journal_Client.h"
 
#include <iostream>
 
int main()
{
 joedb::Local_Connector connector("blobs.joedb.sock");
 joedb::Server_File server_file(connector);
 joedb::Writable_Journal_Client client(server_file, server_file);
 
 const auto blob = client.transaction([](joedb::Writable_Journal &journal)
 {
  return journal.write_blob("blob");
 });
 
 std::cout << server_file.read_blob(blob) << '\n';
 
 return 0;
}

Definition at line 21 of file Server_File.h.

Constructor & Destructor Documentation

◆ Server_File()

joedb::Server_File::Server_File	(	const Connector &	connector,
		Logger &	logger = `Logger::dummy_logger`
	)

Definition at line 21 of file Server_File.cpp.

Member Function Documentation

◆ get_size()

int64_t joedb::Server_File::get_size ( ) const

inlineoverridevirtual

Reimplemented from joedb::Abstract_File.

Definition at line 69 of file Server_File.h.

◆ handshake()

int64_t joedb::Server_File::handshake	(	const Readonly_Journal &	client_journal,
		Content_Check	content_check
	)

overridevirtual

Parameters

client_journal	may be used to check matching content
content_check	indicates how matching content is tested

Returns: connection checkpoint

Reimplemented from joedb::Robust_Connection.

Definition at line 62 of file Server_File.cpp.

◆ pread()

size_t joedb::Server_File::pread	(	char *	data,
		size_t	size,
		int64_t	offset
	)		const

overridevirtual

The returned value may be less than size, even if the end of the file is not reached. 0 is returned if the end of the file is reached.

Reimplemented from joedb::Abstract_File.

Definition at line 104 of file Server_File.cpp.

◆ pull()

int64_t joedb::Server_File::pull	(	Lock_Action	lock_action,
		Data_Transfer	data_transfer,
		Writable_Journal &	client_journal,
		std::chrono::milliseconds	wait
	)

overridevirtual

Parameters

lock_action	whether the connection should be locked before pulling
data_transfer	whether data should be transferred
client_journal	journal to pull into
wait	duration during which the connection may wait for new data if the pull would otherwise be empty

Returns: connection checkpoint

Reimplemented from joedb::Robust_Connection.

Definition at line 34 of file Server_File.cpp.

◆ push()

int64_t joedb::Server_File::push	(	const Readonly_Journal &	client_journal,
		int64_t	from,
		int64_t	until,
		Unlock_Action	unlock_action
	)

overridevirtual

Returns: connection checkpoint

Reimplemented from joedb::Robust_Connection.

Definition at line 75 of file Server_File.cpp.

◆ pwrite()

void joedb::Server_File::pwrite	(	const char *	data,
		size_t	size,
		int64_t	offset
	)

overridevirtual

Reimplemented from joedb::Abstract_File.

Definition at line 117 of file Server_File.cpp.

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

/home/rcoulom/repos/joedb/src/joedb/concurrency/Server_File.h
/home/rcoulom/repos/joedb/src/joedb/concurrency/Server_File.cpp

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Server_File()

Member Function Documentation

◆ get_size()

◆ handshake()

◆ pread()

◆ pull()

◆ push()

◆ pwrite()