command Class Reference

common structure of a generic command More...

#include <command.h>

List of all members.

Public Member Functions

command ()

null constructor

command (int id, const char *file_name, int max_clients=0, int port=0)

initialization constructor

char * to_string ()

translates the command in a string

int fill_from_string (const char *s)

fills the class members using a string

Public Attributes

int id

identifies the command type

string file_name

file on which the command needs to be executed

int max_clients

max number of clients on a particular file

int port

port on which the file is reachable

Friends

int send_command (int sock, command com, int *rep_data_size, char **rep_data)

friend function (forward declaration)

int receive_command (int sock, command *com)

friend function (forward declaration)

Detailed Description

common structure of a generic command

i have built a single class for any command type, possible commands are the following:

register_file
unregister_file
start_file_transfer
end_file_transfer
reg_notification
notify
get_file

to each of them has been associated an int value through a macro as shown in this file.

Definition at line 72 of file command.h.

Constructor & Destructor Documentation

command::command ( )

null constructor

it makes yust some null initialization

Definition at line 10 of file command.cpp.

References file_name, max_clients, and port.

command::command	(	int	id,
		const char *	file_name,
		int	max_clients = `0`,
		int	port = `0`
	)

initialization constructor

using this type of constructor the user can set the 4 memer fields of the command object

Definition at line 17 of file command.cpp.

Member Function Documentation

int command::fill_from_string ( const char * s )

fills the class members using a string

parsing the string s, this function assigns values to each member of the command class, we assume that the string passed as parameter s is a string built using the to_string() function, as previously described. if this is not the case, the fill_from_string() method will recognise the unvalid string and return an error value

Parameters:

s

| string to be parsed to build the command

Returns:: -1 on error, 0 if everything is ok

Definition at line 51 of file command.cpp.

References file_name, max_clients, and port.

Referenced by receive_command().

char * command::to_string ( )

translates the command in a string

commands need to be transmitted on the network, this functions builds a string containing the information to reconstruct the command structure again at delivery. the built string has the following structure:

<id|max_clients|port|file_name>

if no max_clients or port need to be defined the values will be 0, those are integers presented as strings

Returns:: string result of convertion (dynamically allocated)

Definition at line 26 of file command.cpp.

References file_name, INT_AS_STRING_BYTES, max_clients, and port.

Referenced by send_command().

Friends And Related Function Documentation

int receive_command	(	int	sock,
		command *	com
	)			`[friend]`

friend function (forward declaration)

receive_command() is declared friend to allow use of fill_from_string() private member function

See also:: receive_command()

this function receives a singular command from a channel which must have been previously initialized. It will not return until a command is received, or an error occours. received parameters are saved in the command object pointed by com.

Parameters:

	sock	\| socket from which to receive the command
	com	\| command object to be filled for the caller

Returns:: 0 if everything is ok, -1 otherwise

Definition at line 161 of file command.cpp.

int send_command	(	int	sock,
		command	com,
		int *	rep_data_size,
		char **	rep_data
	)			`[friend]`

friend function (forward declaration)

send_command() is declared friend to allow use of to_string() private member function

See also:: send_command()

this function sends a command to a remote server or client, the connection must be previously established. It will not return until some data are received in response on the socket, this means a state message and eventually some data.

the response data will be one of the following, depending on the command:

register_file -> no data (NULL)
unregister_file -> no data (NULL)
start_file_transfer -> information on how to contact the associated FS
end_file_transfer -> no data (NULL)
reg_notification -> no data (NULL)
notify -> no data (NULL)
get_file -> transferred file

Parameters:

	sock	\| socket to contact the opposite end of the channel
	com	\| command to be sent
	rep_data	\| pointer to data to be returned to the caller (allocated dynamically)
	rep_data_size	\| pointer to an integer to return the size of the rep_data, if any

Returns:: a state code from the following list

See also:

OK

ERR_FILE_NOT_REGISTERED

Definition at line 112 of file command.cpp.

Member Data Documentation

string command::file_name

file on which the command needs to be executed

each command has a file_name parameter, this field will be set in any valid command

Definition at line 90 of file command.h.

Referenced by CL_req_s_body(), command(), fill_from_string(), FS_req_s_body(), req_server(), and to_string().

int command::id

identifies the command type

values are defined here:

See also:

Definition at line 84 of file command.h.

Referenced by CL_req_s_body(), FS_req_s_body(), and req_server().

int command::max_clients

max number of clients on a particular file

this field will be set only in case of register_file command

Definition at line 95 of file command.h.

Referenced by command(), fill_from_string(), FS_req_s_body(), and to_string().

int command::port

port on which the file is reachable

this field will be set only in case of register_file command

Definition at line 100 of file command.h.

Referenced by command(), fill_from_string(), FS_req_s_body(), and to_string().

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

include/command.h
src_common/command.cpp


Public Member Functions
	command ()
	null constructor
	command (int id, const char *file_name, int max_clients=0, int port=0)
	initialization constructor
char *	to_string ()
	translates the command in a string
int	fill_from_string (const char *s)
	fills the class members using a string
Public Attributes
int	id
	identifies the command type
string	file_name
	file on which the command needs to be executed
int	max_clients
	max number of clients on a particular file
int	port
	port on which the file is reachable
Friends
int	send_command (int sock, command com, int rep_data_size, char *rep_data)
	friend function (forward declaration)
int	receive_command (int sock, command *com)
	friend function (forward declaration)