http: Implement trailing headers for chunked transfers

This adds the CURLOPT_TRAILERDATA and CURLOPT_TRAILERFUNCTION
options that allow a callback based approach to sending trailing headers
with chunked transfers.

The test server (sws) was updated to take into account the detection of the
end of transfer in the case of trailing headers presence.

Test 1591 checks that trailing headers can be sent using libcurl.

Closes #3350

1 files changed, 21 insertions, 1 deletions

diff --git a/tests/server/sws.c b/tests/server/sws.c
index cf3d291d9..87c0204c9 100644
--- a/tests/server/sws.c
+++ b/tests/server/sws.c
@@ -253,6 +253,9 @@ SIG_ATOMIC_T got_exit_signal = 0;
 
 static volatile int exit_signal = 0;
 
+/* work around for handling trailing headers */
+static int already_recv_zeroed_chunk = FALSE;
+
 /* signal handler that will be triggered to indicate that the program
   should finish its execution in a controlled manner as soon as possible.
   The first time this is called it will set got_exit_signal to one and
@@ -755,10 +758,27 @@ static int ProcessRequest(struct httprequest *req)
       chunked = TRUE;
     }
 
+
     if(chunked) {
-      if(strstr(req->reqbuf, "\r\n0\r\n\r\n"))
+      if(strstr(req->reqbuf, "\r\n0\r\n\r\n")) {
         /* end of chunks reached */
         return 1; /* done */
+      }
+      else if(strstr(req->reqbuf, "\r\n0\r\n")) {
+        char *last_crlf_char = strstr(req->reqbuf, "\r\n\r\n");
+        while(TRUE) {
+          if(!strstr(last_crlf_char + 4, "\r\n\r\n"))
+            break;
+          last_crlf_char = strstr(last_crlf_char + 4, "\r\n\r\n");
+        }
+        if(last_crlf_char &&
+           last_crlf_char > strstr(req->reqbuf, "\r\n0\r\n"))
+          return 1;
+        already_recv_zeroed_chunk = TRUE;
+        return 0;
+      }
+      else if(already_recv_zeroed_chunk && strstr(req->reqbuf, "\r\n\r\n"))
+        return 1;
       else
         return 0; /* not done */
     }