add ustream, an api for stream buffer management

1 files changed, 138 insertions, 0 deletions

diff --git a/ustream-fd.c b/ustream-fd.c
new file mode 100644
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);
+}