Allow specify schema in capnproto's stream interface (#521)

Author: lixin-wei

CMakeLists.txt

@@ -261,7 +261,12 @@ if (REFLECTCPP_CAPNPROTO)
     if (NOT TARGET CapnProto)
         find_package(CapnProto CONFIG REQUIRED)
     endif ()
-     target_link_libraries(reflectcpp PUBLIC CapnProto::kj CapnProto::capnp CapnProto::capnpc CapnProto::kj-gzip)
+    set(CAPNPC_LIB CapnProto::capnpc)
+    if (NOT TARGET CapnProto::capnpc)
+      # in some old versions, there is no alias target CapnProto::capnpc, fallback to capnc
+      set(CAPNPC_LIB capnpc)
+    endif()
+    target_link_libraries(reflectcpp PUBLIC CapnProto::kj CapnProto::capnp ${CAPNPC_LIB} CapnProto::kj-gzip)
 endif ()
 
 if (REFLECTCPP_CBOR)

include/rfl/capnproto/read.hpp

@@ -76,6 +76,11 @@ auto read(std::istream& _stream) {
   return read<T, Ps...>(bytes.data(), bytes.size());
 }
 
+template <class T, class... Ps>
+auto read(std::istream& _stream, const Schema<T>& _schema) {
+  return read<T, Ps...>(_stream, _schema);
+}
+
 }  // namespace rfl::capnproto
 
 #endif

include/rfl/capnproto/write.hpp

@@ -62,6 +62,13 @@ std::ostream& write(const auto& _obj, std::ostream& _stream) {
   return _stream;
 }
 
+template <class... Ps>
+std::ostream& write(const auto& _obj, const auto& _schema, std::ostream& _stream) {
+  auto buffer = write<Ps...>(_obj, _schema);
+  _stream.write(buffer.data(), buffer.size());
+  return _stream;
+}
+
 }  // namespace rfl::capnproto
 
 #endif