From 06ed35ae41a8c63af47b327cd0be0e2fb90166e8 Mon Sep 17 00:00:00 2001
From: "Dr. Patrick Urbanke" <patrick@getml.com>
Date: Thu, 26 Dec 2024 12:45:12 +0100
Subject: [PATCH] Implemented rfl::capnproto::read

---
 include/rfl/capnproto.hpp       |  4 ++--
 include/rfl/capnproto/read.hpp  | 27 ++++++++++++---------------
 tests/capnproto/test_person.cpp |  7 +++++--
 3 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/include/rfl/capnproto.hpp b/include/rfl/capnproto.hpp
index d3d74ca0..52a35c06 100644
--- a/include/rfl/capnproto.hpp
+++ b/include/rfl/capnproto.hpp
@@ -2,12 +2,12 @@
 #define RFL_CAPNPROTO_HPP_
 
 #include "../rfl.hpp"
-// #include "capnproto/Parser.hpp"
+#include "capnproto/Parser.hpp"
 #include "capnproto/Reader.hpp"
 #include "capnproto/Schema.hpp"
 #include "capnproto/Writer.hpp"
 // #include "capnproto/load.hpp"
-// #include "capnproto/read.hpp"
+#include "capnproto/read.hpp"
 // #include "capnproto/save.hpp"
 // #include "capnproto/to_schema.hpp"
 #include "capnproto/write.hpp"
diff --git a/include/rfl/capnproto/read.hpp b/include/rfl/capnproto/read.hpp
index 01e8c0bd..f8d95efb 100644
--- a/include/rfl/capnproto/read.hpp
+++ b/include/rfl/capnproto/read.hpp
@@ -1,7 +1,9 @@
 #ifndef RFL_CAPNPROTO_READ_HPP_
 #define RFL_CAPNPROTO_READ_HPP_
 
-#include <capnproto.h>
+#include <capnp/dynamic.h>
+#include <capnp/serialize-packed.h>
+#include <kj/io.h>
 
 #include <bit>
 #include <istream>
@@ -31,20 +33,15 @@ auto read(const InputVarType& _obj) {
 template <class T, class... Ps>
 Result<internal::wrap_in_rfl_array_t<T>> read(
     const char* _bytes, const size_t _size, const Schema<T>& _schema) noexcept {
-  capnproto_reader_t capnproto_reader = capnproto_reader_memory(_bytes, _size);
-  capnproto_value_t root;
-  capnproto_generic_value_new(_schema.iface(), &root);
-  auto err = capnproto_value_read(capnproto_reader, &root);
-  if (err) {
-    capnproto_value_decref(&root);
-    capnproto_reader_free(capnproto_reader);
-    return Error(std::string("Could not read root value: ") +
-                 capnproto_strerror());
-  }
-  auto result = read<T, Ps...>(InputVarType{&root});
-  capnproto_value_decref(&root);
-  capnproto_reader_free(capnproto_reader);
-  return result;
+  const auto array_ptr = kj::ArrayPtr<const kj::byte>(
+      internal::ptr_cast<const kj::byte*>(_bytes), _size);
+  auto input_stream = kj::ArrayInputStream(array_ptr);
+  auto message_reader = capnp::PackedMessageReader(input_stream);
+  // TODO: Person is hardcoded.
+  const auto root_schema = _schema.value().getNested("Person");
+  const auto input_var = InputVarType{
+      message_reader.getRoot<capnp::DynamicStruct>(root_schema.asStruct())};
+  return read<T, Ps...>(input_var);
 }
 
 /// Parses an object from CAPNPROTO using reflection.
diff --git a/tests/capnproto/test_person.cpp b/tests/capnproto/test_person.cpp
index 67b8dbe8..f3e16383 100644
--- a/tests/capnproto/test_person.cpp
+++ b/tests/capnproto/test_person.cpp
@@ -27,7 +27,10 @@ struct Person {
 TEST(capnproto, test_person) {
   const auto schema =
       rfl::capnproto::Schema<Person>::from_string(PERSON_SCHEMA).value();
-  const auto homer = Person{.firstName = "Homer", .lastName = "Simpson"};
-  std::cout << rfl::capnproto::write(homer, schema).data() << std::endl;
+  const auto homer1 = Person{.firstName = "Homer", .lastName = "Simpson"};
+  const auto serialized1 = rfl::capnproto::write(homer1, schema);
+  const auto homer2 = rfl::capnproto::read<Person>(serialized1, schema).value();
+  const auto serialized2 = rfl::capnproto::write(homer2, schema);
+  EXPECT_EQ(serialized1, serialized2);
 }
 }  // namespace test_tutorial_example