tdf#152493 ucb WebDAV: fix upload using HTTP 1.0 fallback

Fix broken libcurl upload to Vibe 4.0.6 WebDAV server
using HTTP 1.0 fallback.

Regression from commit 023ebf1789
"ucb: remove --with-webdav=neon" (Neon had no such upload
problem).

HTTP 1.0 fallback found by Pál Zoltán Kochis.
Fallback for CURLE_UNSUPPORTED_PROTOCOL
suggested by Michael Stahl. Thanks for their and
Attila Bakos' help.

Michael Stahl's comment: "'HTTP/0.9' in the [curl] error
message is very misleading: it simply means that a header
was expected but there was no header, so what is received
is interpreted as body.

Note: the HTTP/1.0 works because it does not use the
'Expect: 100-continue' so there should be no intermediate
100 Continue response from the server at all - instead
libcurl directly sends the XML document for the PROPFIND
and the server sends the response, and the problem does
not occur."

Co-authored-by: Michael Stahl <michael.stahl@allotropia.de>

Change-Id: I8bd79154de14b6425e0324f4d8f6e64512c08264
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/146067
Tested-by: László Németh <nemeth@numbertext.org>
Reviewed-by: László Németh <nemeth@numbertext.org>

ucb/source/ucp/webdav-curl/CurlSession.cxx

@@ -964,6 +964,8 @@ auto CurlProcessor::ProcessRequestImpl(
                  "curl_easy_perform failed: " << GetErrorString(rc, rSession.m_ErrorBuffer));
         switch (rc)
         {
+            case CURLE_UNSUPPORTED_PROTOCOL:
+                throw DAVException(DAVException::DAV_UNSUPPORTED);
             case CURLE_COULDNT_RESOLVE_PROXY:
                 throw DAVException(
                     DAVException::DAV_HTTP_LOOKUP,
@@ -1250,6 +1252,7 @@ auto CurlProcessor::ProcessRequest(
         }
     }
     bool isRetry(false);
+    bool isFallbackHTTP10(false);
     int nAuthRequests(0);
     int nAuthRequestsProxy(0);
 
@@ -1473,6 +1476,27 @@ auto CurlProcessor::ProcessRequest(
                     }
                 }
             }
+            else if (rException.getError() == DAVException::DAV_UNSUPPORTED)
+            {
+                // tdf#152493 libcurl can't handle "Transfer-Encoding: chunked"
+                // in HTTP/1.1 100 Continue response.
+                // workaround: if HTTP/1.1 didn't work, try HTTP/1.0
+                // (but fallback only once - to prevent infinite loop)
+                if (isFallbackHTTP10)
+                {
+                    throw DAVException(DAVException::DAV_HTTP_ERROR);
+                }
+                isFallbackHTTP10 = true;
+                // note: this is not reset - future requests to this URI use it!
+                auto rc = curl_easy_setopt(rSession.m_pCurl.get(), CURLOPT_HTTP_VERSION,
+                                           CURL_HTTP_VERSION_1_0);
+                if (rc != CURLE_OK)
+                {
+                    throw DAVException(DAVException::DAV_HTTP_ERROR);
+                }
+                SAL_INFO("ucb.ucp.webdav.curl", "attempting fallback to HTTP/1.0");
+                isRetry = true;
+            }
             if (!isRetry)
             {
                 throw; // everything else: re-throw

ucb/source/ucp/webdav-curl/DAVException.hxx

@@ -130,6 +130,7 @@ class DAVException : public std::exception
             DAV_SESSION_CREATE, // session creation error,
                                 // mData = server[:port]
             DAV_INVALID_ARG,    // invalid argument
+            DAV_UNSUPPORTED,    // internal to CurlSession
 
             DAV_LOCK_EXPIRED,   // DAV lock expired