Directly read file served from joedb_server. More...

#include <joedb/concurrency/Server_File.h>

Inheritance diagram for joedb::Server_File:

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Collaboration diagram for joedb::Server_File:

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Public Member Functions
	Server_File (Channel &channel)

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

int64_t	pull (Writable_Journal &client_journal, std::chrono::milliseconds wait) override
	Pull new data from the connection.

int64_t	lock_pull (Writable_Journal &client_journal, std::chrono::milliseconds wait) override
	Fused lock_pull, executed at the start of a write transaction.

int64_t	push_until (Readonly_Journal &client_journal, int64_t server_position, int64_t until_position, bool unlock_after) override
	Push new data to the connection.

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

void	pwrite (const char *data, size_t size, int64_t offset) override

int64_t	get_size () const override

std::string	read_blob_data (Blob blob) const override

Public Member Functions inherited from joedb::Server_Connection
	Server_Connection (Channel &channel)

int64_t	get_checkpoint (Readonly_Journal &client_journal, std::chrono::milliseconds wait) override
	Get new connection checkpoint without pulling.

void	unlock () override
	Can be used to cancel a transaction without pushing.

Public Member Functions inherited from joedb::Server_Client
	Server_Client (Channel &channel)

void	set_log (std::ostream *stream)

void	set_keep_alive_interval (std::chrono::seconds duration)

int64_t	get_session_id () const

Thread_Safe_Channel &	get_channel ()

void	ping ()

	~Server_Client ()

Public Member Functions inherited from joedb::Connection
int64_t	push (Readonly_Journal &client_journal, int64_t from_checkpoint, bool unlock_after)
	Shortcut to call push_until until the client checkpoint.

virtual	~Connection ()

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

void	flush ()

void	flush_and_sync ()

void	exclusive_lock_tail ()

void	unlock_tail () noexcept

bool	tail_is_locked () const noexcept

void	shared_lock_head ()

void	exclusive_lock_head ()

void	unlock_head () noexcept

bool	is_shared () const noexcept

bool	is_readonly () const noexcept

void	set_position (int64_t position)

int64_t	get_position () const noexcept

virtual void	copy_to (Buffered_File &destination, int64_t start, int64_t size)

void	copy_to (Buffered_File &destination)

template<typename T >
void	write (T x)

template<typename T >
T	read ()

template<typename T >
void	compact_write (T x)

template<typename T >
T	compact_read ()

template<typename T >
T	read_strong_type ()

void	write_reference (Record_Id id)

Record_Id	read_reference ()

void	write_string (const std::string &s)

std::string	read_string ()

void	write_blob (Blob blob)

Blob	read_blob ()

std::string	safe_read_string (int64_t max_size)

void	write_data (const char *data, size_t n)

size_t	read_data (char *data, const size_t n)

void	ignore (const int64_t n)

Public Member Functions inherited from joedb::Sequential_File
void	sequential_seek (int64_t new_position)

size_t	sequential_read (char *data, size_t size)

void	sequential_write (const char *data, size_t size)

int64_t	get_position () const

Public Member Functions inherited from joedb::Abstract_File
virtual void	sync ()

virtual void	shared_lock (int64_t start, int64_t size)

virtual void	exclusive_lock (int64_t start, int64_t size)

virtual void	unlock (int64_t start, int64_t size) noexcept

virtual	~Abstract_File ()=default

Additional Inherited Members
Static Public Attributes inherited from joedb::Buffered_File
static constexpr int64_t	last_position = (1ULL << 63) - 1

Protected Member Functions inherited from joedb::Server_Connection
int64_t	pull (Writable_Journal *client_journal, std::chrono::milliseconds wait, char pull_type)

bool	check_matching_content (Readonly_Journal &client_journal, int64_t server_checkpoint)

Protected Member Functions inherited from joedb::Server_Client
void	download (Async_Writer &writer, Channel_Lock &lock, int64_t size) const

Protected Member Functions inherited from joedb::Buffered_File
void	destructor_flush () noexcept

void	make_readonly ()

void	make_writable ()

Static Protected Member Functions inherited from joedb::Connection
static void	content_mismatch ()

Protected Attributes inherited from joedb::Server_Client
Thread_Safe_Channel	channel

std::ostream *	log

bool	connected

Buffer< 13 >	buffer

int64_t	session_id

bool	pullonly_server

int64_t	server_checkpoint

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.

A demo can be found in write_server_blob.cpp:

#include "joedb/ui/main_exception_catcher.h"
#include "joedb/concurrency/Network_Channel.h"
#include "joedb/concurrency/Server_File.h"
#include "joedb/concurrency/Writable_Journal_Client.h"
 
#include <iostream>
 
/// Demonstration of joedb::Server_File
///
/// This demonstrates how to connect to a joedb server to read and write blobs,
/// without downloading a full replica of the database.
static int write_server_blob(int argc, char **argv)
{
 if (argc < 3)
 {
  std::cerr << "usage: " << argv[0] << " <port> <blob_string>\n";
  std::cerr << "This program will try to connect to a server on localhost.\n";
  std::cerr << "Before running this program, start a joedb server with:\n";
  std::cerr << "joedb_server -port <port> blobs.joedb\n";
  std::cerr << "You can interactively read and write blobs this way:\n";
  std::cerr << "joedb_client --nodb server network localhost <port>\n";
  return 1;
 }
 
 // Connect to the server
 joedb::Network_Channel channel("localhost", argv[1]);
 joedb::Server_File server_file(channel);
 
 // Creating the client: server file serves both as file and connection
 joedb::Writable_Journal_Client client(server_file, server_file);
 
 // Write blobs with a Client_Lock: keeps the server locked between writes
 {
  joedb::Writable_Journal_Client_Lock lock(client);
 
  for (int i = 3; --i >= 0;)
  {
   const joedb::Blob blob = lock.get_journal().write_blob_data(argv[2]);
   lock.push();
   std::cout << "wrote blob with lock: " << blob.get_position() << '\n';
   std::cout << "blob: " << server_file.read_blob_data(blob) << '\n';
  }
 
  lock.unlock();
 }
 
 // Write blobs with a transaction: lock and unlock for each write
 for (int i = 3; --i >= 0;)
 {
  joedb::Blob blob;
  client.transaction([&blob, argv](joedb::Writable_Journal &journal)
  {
   blob = journal.write_blob_data(argv[2]);
  });
  std::cout << "wrote blob with transaction: " << blob.get_position() << '\n';
  std::cout << "blob: " << server_file.read_blob_data(blob) << '\n';
 }
 
 return 0;
}
 
int main(int argc, char **argv)
{
 return joedb::main_exception_catcher(write_server_blob, argc, argv);
}

Definition at line 22 of file Server_File.h.

Constructor & Destructor Documentation

◆ Server_File()

joedb::Server_File::Server_File ( Channel & channel )

Definition at line 45 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 77 of file Server_File.h.

◆ handshake()

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

overridevirtual

Parameters

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

Return values

server_checkpoint

Reimplemented from joedb::Server_Connection.

Definition at line 76 of file Server_File.cpp.

◆ lock_pull()

int64_t joedb::Server_File::lock_pull	(	Writable_Journal &	client_journal,
		std::chrono::milliseconds	wait
	)

overridevirtual

Return values

server_checkpoint

Reimplemented from joedb::Server_Connection.

Definition at line 100 of file Server_File.cpp.

◆ pread()

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

overridevirtual

Reimplemented from joedb::Abstract_File.

Definition at line 140 of file Server_File.cpp.

◆ pull()

int64_t joedb::Server_File::pull	(	Writable_Journal &	client_journal,
		std::chrono::milliseconds	wait
	)

overridevirtual

Parameters

client_journal	journal to pull into
wait	duration during which the connection may wait for new data if the pull would otherwise be empty

Return values

server_checkpoint

Reimplemented from joedb::Server_Connection.

Definition at line 89 of file Server_File.cpp.

◆ push_until()

int64_t joedb::Server_File::push_until	(	Readonly_Journal &	client_journal,
		int64_t	from_checkpoint,
		int64_t	until_checkpoint,
		bool	unlock_after
	)

overridevirtual

Return values

server_checkpoint

Reimplemented from joedb::Server_Connection.

Definition at line 111 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 153 of file Server_File.cpp.

◆ read_blob_data()

std::string joedb::Server_File::read_blob_data ( Blob blob ) const

overridevirtual

Reimplemented from joedb::Buffered_File.

Definition at line 170 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()

◆ lock_pull()

◆ pread()

◆ pull()

◆ push_until()

◆ pwrite()

◆ read_blob_data()