add ustream, an api for stream buffer management

[project/libubox.git] / ustream-fd.c

diff --git a/ustream-fd.c b/ustream-fd.c
new file mode 100644 (file)
index 0000000..c2e70db
--- /dev/null
+++ b/ustream-fd.c
@@ -0,0 +1,138 @@
+/*
+ * 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)
+{
+       struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
+       struct ustream_buf *buf;
+       unsigned int flags = ULOOP_EDGE_TRIGGER;
+
+       if (!s->read_blocked && !s->eof)
+               flags |= ULOOP_READ;
+
+       buf = s->w.head;
+       if (buf && s->w.data_bytes && !s->write_error)
+               flags |= ULOOP_WRITE;
+
+       uloop_fd_add(&sf->fd, flags);
+
+       if (flags & ULOOP_READ)
+               sf->fd.cb(&sf->fd, ULOOP_READ);
+}
+
+static void ustream_fd_read_pending(struct ustream_fd *sf, bool *update)
+{
+       struct ustream *s = &sf->stream;
+       int buflen = 0;
+       ssize_t len;
+       char *buf;
+
+       do {
+               buf = ustream_reserve(s, 1, &buflen);
+               if (!buf)
+                       break;
+
+               len = read(sf->fd.fd, buf, buflen);
+               if (!len) {
+                       sf->fd.eof = true;
+                       return;
+               }
+
+               if (len < 0) {
+                       if (errno == EINTR)
+                               continue;
+
+                       if (errno == EAGAIN)
+                               return;
+               }
+
+               ustream_fill_read(s, len);
+       } 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 len;
+
+       if (!buflen)
+               return 0;
+
+retry:
+       len = write(sf->fd.fd, buf, buflen);
+       if (!len)
+               goto retry;
+
+       if (len < 0) {
+               if (errno == EINTR)
+                       goto retry;
+
+               if (errno == EAGAIN || errno == EWOULDBLOCK)
+                       return 0;
+       }
+
+       return len;
+}
+
+static void ustream_uloop_cb(struct uloop_fd *fd, unsigned int events)
+{
+       struct ustream_fd *sf = container_of(fd, struct ustream_fd, fd);
+       struct ustream *s = &sf->stream;
+       bool update = false;
+
+       if (events & ULOOP_READ)
+               ustream_fd_read_pending(sf, &update);
+
+       if (events & ULOOP_WRITE) {
+               if (ustream_write_pending(s))
+                       ustream_fd_set_uloop(s);
+       }
+
+       if (!s->eof && fd->eof) {
+               s->eof = true;
+               ustream_fd_set_uloop(s);
+               ustream_state_change(s);
+       }
+}
+
+
+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_uloop;
+       s->write = ustream_fd_write;
+       s->free = ustream_fd_free;
+       ustream_fd_set_uloop(s);
+}