[Spice-devel] [spice-gtk v2 2/4] spice-channel: spice_channel_read_wire() improvements

[Victor Toso]

From: Victor Toso <me at victortoso.com>

* Removes the reread label by having while(TRUE);

  The label is being used after g_coroutine_socket_wait() is called,
  which is context switch while we can't do the reading as it would
  block. Moving this inside a while() makes the code more straight
  forward to be read and should not impact the performance.

* Move local variables inside the block they will be used.

Related: https://bugs.freedesktop.org/show_bug.cgi?id=96598
Signed-off-by: Victor Toso <victortoso at redhat.com>
---
 src/spice-channel.c | 38 ++++++++++++++++++++------------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/src/spice-channel.c b/src/spice-channel.c
index a17c402..d1714df 100644
--- a/src/spice-channel.c
+++ b/src/spice-channel.c
@@ -1025,32 +1025,34 @@ static int spice_channel_read_wire_nonblocking(SpiceChannel *channel,
 static int spice_channel_read_wire(SpiceChannel *channel, void *data, size_t len)
 {
     SpiceChannelPrivate *c = channel->priv;
-    GIOCondition cond;
-    gssize ret;
 
-reread:
+    while (TRUE) {
+        gssize ret;
+        GIOCondition cond;
 
-    if (c->has_error) return 0; /* has_error is set by disconnect(), return no error */
+        if (c->has_error) {
+            /* has_error is set by disconnect(), return no error */
+            return 0;
+        }
 
-    ret = spice_channel_read_wire_nonblocking(channel, data, len, &cond);
+        ret = spice_channel_read_wire_nonblocking(channel, data, len, &cond);
+        if (ret > 0)
+            return ret;
 
-    if (ret == -1) {
-        if (cond != 0) {
-            // TODO: should use g_pollable_input/output_stream_create_source() ?
-            g_coroutine_socket_wait(&c->coroutine, c->sock, cond);
-            goto reread;
-        } else {
+        if (ret == 0) {
+            CHANNEL_DEBUG(channel, "Closing the connection: spice_channel_read() - ret=0");
+            c->has_error = TRUE;
+            return 0;
+        }
+
+        if (cond == 0) {
             c->has_error = TRUE;
             return -errno;
         }
-    }
-    if (ret == 0) {
-        CHANNEL_DEBUG(channel, "Closing the connection: spice_channel_read() - ret=0");
-        c->has_error = TRUE;
-        return 0;
-    }
 
-    return ret;
+        // TODO: should use g_pollable_input/output_stream_create_source() ?
+        g_coroutine_socket_wait(&c->coroutine, c->sock, cond);
+    }
 }
 
 #ifdef HAVE_SASL
-- 
2.9.3