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#include <sys/socket.h>
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include "events.h"
#include "mpool.h"
#include "network.h"
struct network_read_cookie {
int (* callback)(void *, ssize_t);
void * cookie;
int fd;
uint8_t * buf;
size_t buflen;
size_t minlen;
size_t bufpos;
};
MPOOL(network_read_cookie, struct network_read_cookie, 16);
/* Invoke the callback, clean up, and return the callback's status. */
static int
docallback(struct network_read_cookie * C, ssize_t nbytes)
{
int rc;
/* Invoke the callback. */
rc = (C->callback)(C->cookie, nbytes);
/* Clean up. */
mpool_network_read_cookie_free(C);
/* Return the callback's status. */
return (rc);
}
/* The socket is ready for reading/writing. */
static int
callback_buf(void * cookie)
{
struct network_read_cookie * C = cookie;
size_t oplen;
ssize_t len;
/* Attempt to read/write data to/from the buffer. */
oplen = C->buflen - C->bufpos;
len = recv(C->fd, C->buf + C->bufpos, oplen, 0);
/* Failure? */
if (len == -1) {
/* Was it really an error, or just a try-again? */
if ((errno == EAGAIN) ||
#if EAGAIN != EWOULDBLOCK
(errno == EWOULDBLOCK) ||
#endif
(errno == EINTR))
goto tryagain;
/* Something went wrong. */
goto failed;
} else if (len == 0) {
/* The socket was shut down by the remote host. */
goto eof;
}
/* We processed some data. */
C->bufpos += (size_t)len;
/* Do we need to keep going? */
if (C->bufpos < C->minlen)
goto tryagain;
/* Sanity-check: buffer position must fit into a ssize_t. */
assert(C->bufpos <= SSIZE_MAX);
/* Invoke the callback and return. */
return (docallback(C, (ssize_t)C->bufpos));
tryagain:
/* Reset the event. */
if (events_network_register(callback_buf, C, C->fd,
EVENTS_NETWORK_OP_READ))
goto failed;
/* Callback was reset. */
return (0);
eof:
/* Invoke the callback with an EOF status and return. */
return (docallback(C, 0));
failed:
/* Invoke the callback with a failure status and return. */
return (docallback(C, -1));
}
/**
* network_read(fd, buf, buflen, minread, callback, cookie):
* Asynchronously read up to ${buflen} bytes of data from ${fd} into ${buf}.
* When at least ${minread} bytes have been read or on error, invoke
* ${callback}(${cookie}, lenread), where lenread is 0 on EOF or -1 on error,
* and the number of bytes read (between ${minread} and ${buflen} inclusive)
* otherwise. Return a cookie which can be passed to network_read_cancel() in
* order to cancel the read.
*/
void *
network_read(int fd, uint8_t * buf, size_t buflen, size_t minread,
int (* callback)(void *, ssize_t), void * cookie)
{
struct network_read_cookie * C;
/* Make sure buflen is non-zero. */
assert(buflen != 0);
/* Sanity-check: # bytes must fit into a ssize_t. */
assert(buflen <= SSIZE_MAX);
/* Bake a cookie. */
if ((C = mpool_network_read_cookie_malloc()) == NULL)
goto err0;
C->callback = callback;
C->cookie = cookie;
C->fd = fd;
C->buf = buf;
C->buflen = buflen;
C->minlen = minread;
C->bufpos = 0;
/* Register a callback for network readiness. */
if (events_network_register(callback_buf, C, C->fd,
EVENTS_NETWORK_OP_READ))
goto err1;
/* Success! */
return (C);
err1:
mpool_network_read_cookie_free(C);
err0:
/* Failure! */
return (NULL);
}
/**
* network_read_cancel(cookie):
* Cancel the buffer read for which the cookie ${cookie} was returned by
* network_read(). Do not invoke the callback associated with the read.
*/
void
network_read_cancel(void * cookie)
{
struct network_read_cookie * C = cookie;
/* Kill the network event. */
events_network_cancel(C->fd, EVENTS_NETWORK_OP_READ);
/* Free the cookie. */
mpool_network_read_cookie_free(C);
}
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