client: Split ring_to_iovec() off ring_to_file()

Signed-off-by: Markus Armbruster <armbru@pond.sub.org>

diff --git a/src/client/ringbuf.c b/src/client/ringbuf.c
index 82e772dc30ca15aef2fef628ef33aa50c17767a4..ec79ef86db76976ab81304924cc12e9e54c7fe24 100644 (file)
--- a/src/client/ringbuf.c
+++ b/src/client/ringbuf.c
@@ -27,7 +27,7 @@
  *  ringbuf.c: Simple ring buffer
  *
  *  Known contributors to this file:
  *  ringbuf.c: Simple ring buffer
  *
  *  Known contributors to this file:

- *     Markus Armbruster, 2007-2015
+ *     Markus Armbruster, 2007-2017

  */
 
 #include <config.h>
  */
 
 #include <config.h>


@@ -215,19 +215,15 @@ ring_from_file(struct ring *r, int fd)
 }
 
 /*
 }
 
 /*

- * Drain ring buffer to file referred by file descriptor @fd.
- * If ring buffer is already empty, do nothing and return 0.
- * Else attempt to write complete contents with writev(), and return
- * its value.
+ * Set up @iov[] to describe complete contents of ring buffer.
+ * @iov[] must have at least two elements.
+ * Return number of elements used (zero for an empty ring buffer).

  */
  */

-int
-ring_to_file(struct ring *r, int fd)
+static int
+ring_to_iovec(struct ring *r, struct iovec iov[])

 {
     unsigned cons = r->cons % RING_SIZE;
     unsigned prod = r->prod % RING_SIZE;
 {
     unsigned cons = r->cons % RING_SIZE;
     unsigned prod = r->prod % RING_SIZE;

-    struct iovec iov[2];
-    int cnt;
-    ssize_t res;

 
     if (r->cons == r->prod)
        return 0;
 
     if (r->cons == r->prod)
        return 0;


@@ -239,15 +235,31 @@ ring_to_file(struct ring *r, int fd)
        /* r->buf[..prod-1] */
        iov[1].iov_base = r->buf;
        iov[1].iov_len = prod;
        /* r->buf[..prod-1] */
        iov[1].iov_base = r->buf;
        iov[1].iov_len = prod;

-       cnt = 2;
+       return 2;

     } else {
        /* r->buf[cons..prod-1] */
        iov[0].iov_len = prod - cons;
     } else {
        /* r->buf[cons..prod-1] */
        iov[0].iov_len = prod - cons;

-       cnt = 1;
+       return 1;

     }
     }

+}
+
+/*
+ * Drain ring buffer to file referred by file descriptor @fd.
+ * If ring buffer is already empty, do nothing and return 0.
+ * Else attempt to write complete contents with writev(), and return
+ * its value.
+ */
+int
+ring_to_file(struct ring *r, int fd)
+{
+    struct iovec iov[2];
+    int cnt;
+    ssize_t res;
+
+    cnt = ring_to_iovec(r, iov);

     res = writev(fd, iov, cnt);
     if (res < 0)
        return res;
     res = writev(fd, iov, cnt);
     if (res < 0)
        return res;

-    r->cons += res;
+    ring_discard(r, res);

     return res;
 }
     return res;
 }