ustream-fd.c

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/*
 * ustream - library for stream buffer management
 *
 * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include "ustream.h"
 
static void ustream_fd_set_uloop(struct ustream *s, bool write)
{
        struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
        struct ustream_buf *buf;
        unsigned int flags = ULOOP_EDGE_TRIGGER | ULOOP_ERROR_CB;
 
        if (!s->read_blocked && !s->eof)
                flags |= ULOOP_READ;
 
        buf = s->w.head;
        if (write || (buf && s->w.data_bytes && !s->write_error))
                flags |= ULOOP_WRITE;
 
        uloop_fd_add(&sf->fd, flags);
}
 
static void ustream_fd_set_read_blocked(struct ustream *s)
{
        ustream_fd_set_uloop(s, false);
}
 
static void ustream_fd_read_pending(struct ustream_fd *sf, bool *more)
{
        struct ustream *s = &sf->stream;
        int buflen = 0;
        ssize_t len;
        char *buf;
 
        do {
                if (s->read_blocked)
                        break;
 
                buf = ustream_reserve(s, 1, &buflen);
                if (!buf)
                        break;
 
                len = read(sf->fd.fd, buf, buflen);
                if (len < 0) {
                        if (errno == EINTR)
                                continue;
 
                        if (errno == EAGAIN || errno == ENOTCONN)
                                return;
 
                        len = 0;
                }
 
                if (!len) {
                        if (!s->eof)
                                ustream_state_change(s);
                        s->eof = true;
                        ustream_fd_set_uloop(s, false);
                        return;
                }
 
                ustream_fill_read(s, len);
                *more = true;
        } while (1);
}
 
static int ustream_fd_write(struct ustream *s, const char *buf, int buflen, bool more)
{
        struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
        ssize_t ret = 0, len;
 
        if (!buflen)
                return 0;
 
        while (buflen) {
                len = write(sf->fd.fd, buf, buflen);
 
                if (len < 0) {
                        if (errno == EINTR)
                                continue;
 
                        if (errno == EAGAIN || errno == EWOULDBLOCK || errno == ENOTCONN)
                                break;
 
                        return -1;
                }
 
                ret += len;
                buf += len;
                buflen -= len;
        }
 
        if (buflen)
                ustream_fd_set_uloop(s, true);
 
        return ret;
}
 
static bool __ustream_fd_poll(struct ustream_fd *sf, unsigned int events)
{
        struct ustream *s = &sf->stream;
        bool more = false;
 
        if (events & ULOOP_READ)
                ustream_fd_read_pending(sf, &more);
 
        if (events & ULOOP_WRITE) {
                bool no_more = ustream_write_pending(s);
                if (no_more)
                        ustream_fd_set_uloop(s, false);
        }
 
        if (sf->fd.error && !s->write_error) {
                ustream_state_change(s);
                s->write_error = true;
                ustream_fd_set_uloop(s, false);
        }
 
        return more;
}
 
static bool ustream_fd_poll(struct ustream *s)
{
        struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
 
        return __ustream_fd_poll(sf, ULOOP_READ | ULOOP_WRITE);
}
 
static void ustream_uloop_cb(struct uloop_fd *fd, unsigned int events)
{
        struct ustream_fd *sf = container_of(fd, struct ustream_fd, fd);
 
        __ustream_fd_poll(sf, events);
}
 
static void ustream_fd_free(struct ustream *s)
{
        struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
 
        uloop_fd_delete(&sf->fd);
}
 
void ustream_fd_init(struct ustream_fd *sf, int fd)
{
        struct ustream *s = &sf->stream;
 
        ustream_init_defaults(s);
 
        sf->fd.fd = fd;
        sf->fd.cb = ustream_uloop_cb;
        s->set_read_blocked = ustream_fd_set_read_blocked;
        s->write = ustream_fd_write;
        s->free = ustream_fd_free;
        s->poll = ustream_fd_poll;
        ustream_fd_set_uloop(s, false);
}