sendrecv: split the I/O handling into private handler

Howard Chu brought the bulk work of this patch that properly
moves out the sending and recving of data to the parts of the
code that are properly responsible for the various ways of doing
so.

Daniel Stenberg assisted with polishing a few bits and fixed some
minor flaws in the original patch.

Another upside of this patch is that we now abuse CURLcodes less
with the "magic" -1 return codes and instead use CURLE_AGAIN more
consistently.

1 files changed, 4 insertions, 8 deletions

diff --git a/lib/transfer.c b/lib/transfer.c
index 92a59d038..c9234a79d 100644
--- a/lib/transfer.c
+++ b/lib/transfer.c
@@ -376,12 +376,11 @@ static CURLcode readwrite_data(struct SessionHandle *data,
   *done = FALSE;
 
   /* This is where we loop until we have read everything there is to
-     read or we get a EWOULDBLOCK */
+     read or we get a CURLE_AGAIN */
   do {
     size_t buffersize = data->set.buffer_size?
       data->set.buffer_size : BUFSIZE;
     size_t bytestoread = buffersize;
-    int readrc;
 
     if(k->size != -1 && !k->header) {
       /* make sure we don't read "too much" if we can help it since we
@@ -394,15 +393,12 @@ static CURLcode readwrite_data(struct SessionHandle *data,
 
     if(bytestoread) {
       /* receive data from the network! */
-      readrc = Curl_read(conn, conn->sockfd, k->buf, bytestoread, &nread);
+      result = Curl_read(conn, conn->sockfd, k->buf, bytestoread, &nread);
 
-      /* subzero, this would've blocked */
-      if(0 > readrc)
+      /* read would've blocked */
+      if(CURLE_AGAIN == result)
         break; /* get out of loop */
 
-      /* get the CURLcode from the int */
-      result = (CURLcode)readrc;
-
       if(result>0)
         return result;
     }