翻譯：使用Libevent的快速可移植非阻塞網路程式設計：非同步IO簡介 (一) (轉)
阿新 • • 發佈：2018-12-23
/* For sockaddr_in */
#include <netinet/in.h>/* For socket functions */
#include <sys/socket.h>/* For fcntl */
#include <fcntl.h>
#include <event2/event.h>
#include <assert.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <
void do_write(evutil_socket_t fd, short events, void*arg);
char
rot13_char(char c)
{
/* We don't want to use isalpha here; setting the locale would change
* which characters are considered alphabetical. */if ((c
return c +13;
elseif ((c >='n'&& c <='z') || (c >='N'&& c <='Z'))
return c -13;
elsereturn c;
}
struct fd_state {
char buffer[MAX_LINE];
size_t buffer_used;
size_t n_written;
size_t write_upto;
structevent*write_event;
};
struct fd_state *
alloc_fd_state(struct event_base *base, evutil_socket_t fd)
{
struct fd_state *state = malloc(sizeof(struct fd_state));
if (!state)
return NULL;
state->read_event = event_new(base, fd, EV_READ|EV_PERSIST, do_read, state);
if (!state->read_event) {
free(state);
return NULL;
}
state->write_event =
event_new(base, fd, EV_WRITE|EV_PERSIST, do_write, state);
if (!state->write_event) {
event_free(state->read_event);
free(state);
return NULL;
}
state->buffer_used = state->n_written = state->write_upto =0;
assert(state->write_event);
return state;
}
void
free_fd_state(struct fd_state *state)
{
event_free(state->read_event);
event_free(state->write_event);
free(state);
}
void
do_read(evutil_socket_t fd, short events, void*arg)
{
struct fd_state *state = arg;
char buf[1024];
int i;
ssize_t result;
while (1) {
assert(state->write_event);
result = recv(fd, buf, sizeof(buf), 0);
if (result <=0)
break;
for (i=0; i < result; ++i) {
if (state->buffer_used <sizeof(state->buffer))
state->buffer[state->buffer_used++] = rot13_char(buf[i]);
if (buf[i] =='\n') {
assert(state->write_event);
event_add(state->write_event, NULL);
state->write_upto = state->buffer_used;
}
}
}
if (result ==0) {
free_fd_state(state);
} elseif (result <0) {
if (errno == EAGAIN) // XXXX use evutil macroreturn;
perror("recv");
free_fd_state(state);
}
}
void
do_write(evutil_socket_t fd, short events, void*arg)
{
struct fd_state *state = arg;
while (state->n_written < state->write_upto) {
ssize_t result = send(fd, state->buffer + state->n_written,
state->write_upto - state->n_written, 0);
if (result <0) {
if (errno == EAGAIN) // XXX use evutil macroreturn;
free_fd_state(state);
return;
}
assert(result !=0);
state->n_written += result;
}
if (state->n_written == state->buffer_used)
state->n_written = state->write_upto = state->buffer_used =1;
event_del(state->write_event);
}
void
do_accept(evutil_socket_t listener, shortevent, void*arg)
{
struct event_base *base= arg;
struct sockaddr_storage ss;
socklen_t slen =sizeof(ss);
int fd = accept(listener, (struct sockaddr*)&ss, &slen);
if (fd <0) { // XXXX eagain?? perror("accept");
} elseif (fd > FD_SETSIZE) {
close(fd); // XXX replace all closes with EVUTIL_CLOSESOCKET */ } else {
struct fd_state *state;
evutil_make_socket_nonblocking(fd);
state = alloc_fd_state(base, fd);
assert(state); /*XXX err*/
assert(state->write_event);
event_add(state->read_event, NULL);
}
}
void
run(void)
{
evutil_socket_t listener;
struct sockaddr_in sin;
struct event_base *base;
structevent*listener_event;
base= event_base_new();
if (!base)
return; /*XXXerr*/
sin.sin_family = AF_INET;
sin.sin_addr.s_addr =0;
sin.sin_port = htons(40713);
listener = socket(AF_INET, SOCK_STREAM, 0);
evutil_make_socket_nonblocking(listener);
#ifndef WIN32
{
int one =1;
setsockopt(listener, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
}
#endifif (bind(listener, (struct sockaddr*)&sin, sizeof(sin)) <0) {
perror("bind");
return;
}
if (listen(listener, 16)<0) {
perror("listen");
return;
}
listener_event = event_new(base, listener, EV_READ|EV_PERSIST, do_accept, (void*)base);
/*XXX check it */
event_add(listener_event, NULL);
event_base_dispatch(base);
}
int
main(int c, char**v)
{
setvbuf(stdout, NULL, _IONBF, 0);
run();
return0;
}
#include <netinet/in.h>/* For socket functions */
#include <sys/socket.h>/* For fcntl */
#include <fcntl.h>
#include <event2/event.h>
#include <assert.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <
void do_write(evutil_socket_t fd, short events, void*arg);
char
rot13_char(char c)
{
/* We don't want to use isalpha here; setting the locale would change
* which characters are considered alphabetical. */if ((c
return c +13;
elseif ((c >='n'&& c <='z') || (c >='N'&& c <='Z'))
return c -13;
elsereturn c;
}
struct fd_state {
char buffer[MAX_LINE];
size_t buffer_used;
size_t n_written;
size_t write_upto;
structevent*write_event;
};
struct fd_state *
alloc_fd_state(struct event_base *base, evutil_socket_t fd)
{
struct fd_state *state = malloc(sizeof(struct fd_state));
if (!state)
return NULL;
state->read_event = event_new(base, fd, EV_READ|EV_PERSIST, do_read, state);
if (!state->read_event) {
free(state);
return NULL;
}
state->write_event =
event_new(base, fd, EV_WRITE|EV_PERSIST, do_write, state);
if (!state->write_event) {
event_free(state->read_event);
free(state);
return NULL;
}
state->buffer_used = state->n_written = state->write_upto =0;
assert(state->write_event);
return state;
}
void
free_fd_state(struct fd_state *state)
{
event_free(state->read_event);
event_free(state->write_event);
free(state);
}
void
do_read(evutil_socket_t fd, short events, void*arg)
{
struct fd_state *state = arg;
char buf[1024];
int i;
ssize_t result;
while (1) {
assert(state->write_event);
result = recv(fd, buf, sizeof(buf), 0);
if (result <=0)
break;
for (i=0; i < result; ++i) {
if (state->buffer_used <sizeof(state->buffer))
state->buffer[state->buffer_used++] = rot13_char(buf[i]);
if (buf[i] =='\n') {
assert(state->write_event);
event_add(state->write_event, NULL);
state->write_upto = state->buffer_used;
}
}
}
if (result ==0) {
free_fd_state(state);
} elseif (result <0) {
if (errno == EAGAIN) // XXXX use evutil macroreturn;
perror("recv");
free_fd_state(state);
}
}
void
do_write(evutil_socket_t fd, short events, void*arg)
{
struct fd_state *state = arg;
while (state->n_written < state->write_upto) {
ssize_t result = send(fd, state->buffer + state->n_written,
state->write_upto - state->n_written, 0);
if (result <0) {
if (errno == EAGAIN) // XXX use evutil macroreturn;
free_fd_state(state);
return;
}
assert(result !=0);
state->n_written += result;
}
if (state->n_written == state->buffer_used)
state->n_written = state->write_upto = state->buffer_used =1;
event_del(state->write_event);
}
void
do_accept(evutil_socket_t listener, shortevent, void*arg)
{
struct event_base *base= arg;
struct sockaddr_storage ss;
socklen_t slen =sizeof(ss);
int fd = accept(listener, (struct sockaddr*)&ss, &slen);
if (fd <0) { // XXXX eagain?? perror("accept");
} elseif (fd > FD_SETSIZE) {
close(fd); // XXX replace all closes with EVUTIL_CLOSESOCKET */ } else {
struct fd_state *state;
evutil_make_socket_nonblocking(fd);
state = alloc_fd_state(base, fd);
assert(state); /*XXX err*/
assert(state->write_event);
event_add(state->read_event, NULL);
}
}
void
run(void)
{
evutil_socket_t listener;
struct sockaddr_in sin;
struct event_base *base;
structevent*listener_event;
base= event_base_new();
if (!base)
return; /*XXXerr*/
sin.sin_family = AF_INET;
sin.sin_addr.s_addr =0;
sin.sin_port = htons(40713);
listener = socket(AF_INET, SOCK_STREAM, 0);
evutil_make_socket_nonblocking(listener);
#ifndef WIN32
{
int one =1;
setsockopt(listener, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
}
#endifif (bind(listener, (struct sockaddr*)&sin, sizeof(sin)) <0) {
perror("bind");
return;
}
if (listen(listener, 16)<0) {
perror("listen");
return;
}
listener_event = event_new(base, listener, EV_READ|EV_PERSIST, do_accept, (void*)base);
/*XXX check it */
event_add(listener_event, NULL);
event_base_dispatch(base);
}
int
main(int c, char**v)
{
setvbuf(stdout, NULL, _IONBF, 0);
run();
return0;
}