[Libreoffice-commits] online.git: Branch 'private/Ashod/nonblocking' - net/socket.hpp

[Ashod Nakashian]

 net/socket.hpp |   28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

New commits:
commit ddb0ea6a9d641488fd5a939fb4e0d2f69ae54da2
Author: Ashod Nakashian <ashod.nakashian at collabora.co.uk>
Date:   Sat Feb 18 13:48:44 2017 -0500

    nb: drain the read buffer before dispatching
    
    Draining the buffer is the correct appraoch
    to avoid accumulating data in the kernel
    unnecessarily. But it also reduces the overhead
    of reparsing the incoming data for message
    boundaries.
    
    The client that is to parse the data should
    parse as many messages as possible and remove
    them from the socket buffer.
    
    Finally, we probably need to cap the maximum
    buffer size to avoid bloating. However this
    heavily depends on the application's max
    message size, assuming there is no separate
    buffer beyond that of the socket to accumulate
    the messages in.
    
    Change-Id: I49c4eccebd474cd07ca84f3f4eae33bc717ed1f2
    Reviewed-on: https://gerrit.libreoffice.org/34411
    Reviewed-by: Ashod Nakashian <ashnakash at gmail.com>
    Tested-by: Ashod Nakashian <ashnakash at gmail.com>

diff --git a/net/socket.hpp b/net/socket.hpp
index 0eec7f0..780c390 100644
--- a/net/socket.hpp
+++ b/net/socket.hpp
@@ -345,16 +345,30 @@ public:
     {
         ssize_t len;
         char buf[4096];
-        do {
-            len = ::read(getFD(), buf, sizeof(buf));
-        } while (len < 0 && errno == EINTR);
-        if (len > 0)
+        bool gotNewData = false;
+        do
+        {
+            // Drain the read buffer.
+            // TODO: Cap the buffer size, lest we grow beyond control.
+            do
+            {
+                len = ::read(getFD(), buf, sizeof(buf));
+            }
+            while (len < 0 && errno == EINTR);
+            if (len > 0)
+            {
+                assert (len < ssize_t(sizeof(buf)));
+                _inBuffer.insert(_inBuffer.end(), &buf[0], &buf[len]);
+                gotNewData = true;
+            }
+            // else poll will handle errors.
+        }
+        while (len > 0);
+
+        if (gotNewData)
         {
-            assert (len < ssize_t(sizeof(buf)));
-            _inBuffer.insert(_inBuffer.end(), &buf[0], &buf[len]);
             handleIncomingMessage();
         }
-        // else poll will handle errors.
 
         return len != 0; // zero is eof / clean socket close.
     }