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/* See LICENSE file for copyright and license details. */
#ifndef COMMUNICATION_H
#define COMMUNICATION_H
#include <stdio.h>
#include <stdlib.h>
#ifndef GCC_ONLY
# if defined(__GNUC__) && !defined(__clang__)
# define GCC_ONLY(...) __VA_ARGS__
# else
# define GCC_ONLY(...) /* nothing */
# endif
#endif
/**
* Construct a message
*
* @param bufp:char** Output parameter for the buffer, must not have side-effects
* @param np:size_t* Output parameter for the size of the buffer sans `extra`
* @param extra:size_t The extra number for bytes to allocate to the buffer
* @param format:string-literal Message format string
* @param ... Message formatting arguments
*/
#define MAKE_MESSAGE(bufp, np, extra, format, ...)\
do {\
ssize_t m__;\
snprintf(NULL, 0, format "%zn", __VA_ARGS__, &m__);\
*(bufp) = malloc((size_t)(extra) + (size_t)m__ + (size_t)1);\
if (!*(bufp))\
return -1;\
sprintf(*(bufp), format, __VA_ARGS__);\
*(np) = (size_t)m__;\
} while (0)
/**
* Send a custom error without an error number
*
* @param ... The error description to send
* @return 1: Client disconnected
* 0: Success (possibily delayed)
* -1: An error occurred
*/
#define send_error(...) ((send_error)(conn, message_id, __VA_ARGS__))
/**
* Send a standard error
*
* @param ... The value of `errno`, 0 to indicate success
* @return 1: Client disconnected
* 0: Success (possibily delayed)
* -1: An error occurred
*/
#define send_errno(...) ((send_errno)(conn, message_id, __VA_ARGS__))
/**
* Send a message
*
* @param conn The index of the connection
* @param buf The data to send
* @param n The size of `buf`
* @return Zero on success, -1 on error, 1 if disconncted
* EINTR, EAGAIN, EWOULDBLOCK, and ECONNRESET count
* as success (ECONNRESET cause 1 to be returned),
* and are handled appropriately.
*/
int send_message(size_t conn, char *restrict buf, size_t n);
/**
* Send a custom error without an error number
*
* @param conn The index of the connection
* @param message_id The ID of the message to which this message is a response
* @param desc The error description to send
* @return 1: Client disconnected
* 0: Success (possibily delayed)
* -1: An error occurred
*/
GCC_ONLY(__attribute__((__nonnull__)))
int (send_error)(size_t conn, const char *restrict message_id, const char *restrict desc);
/**
* Send a standard error
*
* @param conn The index of the connection
* @param message_id The ID of the message to which this message is a response
* @param number The value of `errno`, 0 to indicate success
* @return 1: Client disconnected
* 0: Success (possibily delayed)
* -1: An error occurred
*/
GCC_ONLY(__attribute__((__nonnull__)))
int (send_errno)(size_t conn, const char *restrict message_id, int number);
/**
* Continue sending the queued messages
*
* @param conn The index of the connection
* @return Zero on success, -1 on error, 1 if disconncted
* EINTR, EAGAIN, EWOULDBLOCK, and ECONNRESET count
* as success (ECONNRESET cause 1 to be returned),
* and are handled appropriately.
*/
static inline int
continue_send(size_t conn)
{
return send_message(conn, NULL, 0);
}
#endif
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