Correctly parse multi-buffer JSON messages (RIPD-1306):

When attempting to parse a BufferSequence as a JSON object,
if the sequence contained more than buffer, the JSON parser
would incorrectly attempt to decode each buffer as a separate
JSON object, instead of one complete object.

src/ripple/json/json_reader.h

@@ -176,13 +176,11 @@ bool
 Reader::parse(Value& root, BufferSequence const& bs)
 {
     using namespace boost::asio;
+    std::string s;
+    s.reserve (buffer_size(bs));
     for (auto const& b : bs)
-    {
-        auto begin = buffer_cast<const char*>(b);
-        if(! parse(begin, begin + buffer_size(b), root))
-            return false;
-    }
-    return true;
+        s.append(buffer_cast<char const*>(b), buffer_size(b));
+    return parse(s, root);
 }
 
 /** \brief Read from 'sin' into 'root'.

src/test/app/Regression_test.cpp

@@ -208,11 +208,9 @@ struct Regression_test : public beast::unit_test::suite
 
         std::string const request = R"json({"command":"path_find","id":19,"subcommand":"create","source_account":"rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh","destination_account":"rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh","destination_amount":"1000000","source_currencies":[{"currency":"0000000000000000000000000000000000000000"},{"currency":"0000000000000000000000005553440000000000"},{"currency":"0000000000000000000000004254430000000000"},{"issuer":"rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh","currency":"0000000000000000000000004254430000000000"},{"issuer":"rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh","currency":"0000000000000000000000004254430000000000"},{"issuer":"rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh","currency":"0000000000000000000000004555520000000000"},{"currency":"0000000000000000000000004554480000000000"},{"currency":"0000000000000000000000004A50590000000000"},{"issuer":"rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh","currency":"000000000000000000000000434E590000000000"},{"currency":"0000000000000000000000004742490000000000"},{"issuer":"rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh","currency":"0000000000000000000000004341440000000000"}]})json";
 
-
         Json::Value jvRequest;
         Json::Reader jrReader;
 
-
         std::vector<boost::asio::const_buffer> buffers;
         buffers.emplace_back(buffer(request, 1024));
         buffers.emplace_back(buffer(request.data() + 1024, request.length() - 1024));