_libssh2_channel_write: general code cleanup

simplified the function and removed some unused struct fields

src/channel.c

@@ -1994,8 +1994,6 @@ _libssh2_channel_write(LIBSSH2_CHANNEL *channel, int stream_id,
         buflen = 32700;
 
     if (channel->write_state == libssh2_NB_state_idle) {
-        channel->write_bufwrote = 0;
-
         _libssh2_debug(session, LIBSSH2_TRACE_CONN,
                        "Writing %d bytes on channel %lu/%lu, stream #%d",
                        (int) buflen, channel->local.id, channel->remote.id,
@@ -2012,18 +2010,12 @@ _libssh2_channel_write(LIBSSH2_CHANNEL *channel, int stream_id,
                                   "data might be ignored");
         }
 
-        /* [13] 9 = packet_type(1) + channelno(4) [ + streamid(4) ] +
-           buflen(4) */
-        channel->write_packet_len = (stream_id ? 13 : 9);
         channel->write_state = libssh2_NB_state_allocated;
     }
 
-    /* Deduct the amount that has already been sent, and set buf accordingly. */
-    buflen -= channel->write_bufwrote;
-    buf += channel->write_bufwrote;
 
-    while (buflen > 0) {
     if (channel->write_state == libssh2_NB_state_allocated) {
+        unsigned char *s = channel->write_packet;
 
         /* drain the incoming flow first */
         do
@@ -2031,19 +2023,18 @@ _libssh2_channel_write(LIBSSH2_CHANNEL *channel, int stream_id,
         while (rc > 0);
 
         if(channel->local.window_size <= 0) {
-                /* there's no more room for data so we stop sending now */
+            /* there's no room for data so we stop */
-                break;
+            channel->write_state = libssh2_NB_state_idle;
+            return 0;
         }
 
         channel->write_bufwrite = buflen;
-            channel->write_s = channel->write_packet;
 
-            *(channel->write_s++) =
+        *(s++) = stream_id ? SSH_MSG_CHANNEL_EXTENDED_DATA :
-                stream_id ? SSH_MSG_CHANNEL_EXTENDED_DATA :
             SSH_MSG_CHANNEL_DATA;
-            _libssh2_store_u32(&channel->write_s, channel->remote.id);
+        _libssh2_store_u32(&s, channel->remote.id);
         if (stream_id)
-                _libssh2_store_u32(&channel->write_s, stream_id);
+            _libssh2_store_u32(&s, stream_id);
 
         /* Don't exceed the remote end's limits */
         /* REMEMBER local means local as the SOURCE of the data */
@@ -2065,7 +2056,8 @@ _libssh2_channel_write(LIBSSH2_CHANNEL *channel, int stream_id,
         }
         /* store the size here only, the buffer is passed in as-is to
            _libssh2_transport_send() */
-            _libssh2_store_u32(&channel->write_s, channel->write_bufwrite);
+        _libssh2_store_u32(&s, channel->write_bufwrite);
+        channel->write_packet_len = s - channel->write_packet;
 
         _libssh2_debug(session, LIBSSH2_TRACE_CONN,
                        "Sending %d bytes on channel %lu/%lu, stream_id=%d",
@@ -2077,8 +2069,7 @@ _libssh2_channel_write(LIBSSH2_CHANNEL *channel, int stream_id,
 
     if (channel->write_state == libssh2_NB_state_created) {
         rc = _libssh2_transport_send(session, channel->write_packet,
-                                         channel->write_s -
+                                     channel->write_packet_len,
-                                         channel->write_packet,
                                      buf, channel->write_bufwrite);
         if (rc == LIBSSH2_ERROR_EAGAIN) {
             return _libssh2_error(session, rc,
@@ -2103,13 +2094,13 @@ _libssh2_channel_write(LIBSSH2_CHANNEL *channel, int stream_id,
            both about sent data as well as EAGAIN. So, by returning short
            now, the caller will call this function again with new data to
            send */
-            break;
-        }
-    }
 
         channel->write_state = libssh2_NB_state_idle;
 
         return wrote;
+    }
+
+    return LIBSSH2_ERROR_INVAL; /* reaching this point is really bad */
 }
 
 /*

src/libssh2_priv.h

@@ -398,9 +398,7 @@ struct _LIBSSH2_CHANNEL
     /* State variables used in libssh2_channel_write_ex() */
     libssh2_nonblocking_states write_state;
     unsigned char write_packet[13];
-    unsigned char *write_s;
     size_t write_packet_len;
-    size_t write_bufwrote;
     size_t write_bufwrite;
 
     /* State variables used in libssh2_channel_close() */