From 7250a86b7eab2692d5c17d071436c84bac4574df Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Thu, 29 Jun 2023 14:40:16 +0200
Subject: c++,codec-json: Implemented Tuple Decoding

---
 src/codec-json/json.tmpl.h | 62 +++++++++++++++++++++++++++++++++++++++++++++-
 tests/codec-json.cpp       |  9 ++++++-
 2 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/src/codec-json/json.tmpl.h b/src/codec-json/json.tmpl.h
index 6cf7189..3d3ad91 100644
--- a/src/codec-json/json.tmpl.h
+++ b/src/codec-json/json.tmpl.h
@@ -3,6 +3,8 @@
 #include <charconv>
 #include <sstream>
 
+#include <iostream>
+
 namespace saw {
 namespace impl {
 template<typename Schema, typename RootSchema, typename FromEncode>
@@ -468,7 +470,7 @@ struct json_decode<schema::Struct<schema::Member<T,Lits>...>, RootSchema, ToDeco
 			constexpr static string_literal Literal = parameter_key_pack_type<i, Lits...>::literal;
 			if(search_name == Literal.view()){
 				if(fields[i]){
-					// TODO Change to this
+					// TODO Change to this. Maybe
 					// return make_error<err::already_exists>();
 					return make_error<err::invalid_state>();
 				}
@@ -547,6 +549,8 @@ struct json_decode<schema::Struct<schema::Member<T,Lits>...>, RootSchema, ToDeco
 		if(buff.read_composite_length() == 0){
 			return make_error<err::buffer_exhausted>();
 		}
+
+		// Check if there are no elements present in the JSON Struct
 		if(buff.read() == '}'){
 			if(sizeof...(T) > 0){
 				return make_error<err::invalid_state>();
@@ -564,6 +568,62 @@ struct json_decode<schema::Struct<schema::Member<T,Lits>...>, RootSchema, ToDeco
 	}
 };
 
+template<typename... T, typename RootSchema, typename ToDecode>
+struct json_decode<schema::Tuple<T...>, RootSchema, ToDecode> {
+	template<std::size_t i>
+	static error_or<void> decode_element(buffer_view& buff, data<schema::Tuple<T...>, ToDecode>& to){
+		if constexpr (i < sizeof...(T)){
+			if constexpr ( i > 0 ){
+				if(buff.read() != ','){
+					return make_error<err::invalid_state>();
+				}
+				buff.read_advance(1);
+				if(buff.read_composite_length() == 0){
+					return make_error<err::buffer_exhausted>();
+				}
+			}
+			using Type = typename parameter_pack_type<i, T...>::type;
+
+			auto eov = json_decode<Type, RootSchema, ToDecode>::decode(buff, to.template get<i>());
+			if(eov.is_error()){
+				return eov;
+			}
+			json_helper::skip_whitespace(buff);
+			if(buff.read_composite_length() == 0){
+				return make_error<err::buffer_exhausted>();
+			}
+
+			eov = decode_element<i+1>(buff, to);
+			if(eov.is_error()){
+				return eov;
+			}
+		}else{
+			if(buff.read() != ']'){
+				return make_error<err::invalid_state>();
+			}
+			buff.read_advance(1);
+		}
+		return void_t{};
+	}
+
+	static error_or<void> decode(buffer_view& buff, data<schema::Tuple<T...>, ToDecode>& to){
+		assert(buff.read() == '[');
+		buff.read_advance(1);
+
+		json_helper::skip_whitespace(buff);
+		if(buff.read_composite_length() == 0){
+			return make_error<err::buffer_exhausted>();
+		}
+
+		auto eov = decode_element<0>(buff, to);
+		if(eov.is_error()){
+			return eov;
+		}
+
+		return void_t{};
+	}
+};
+
 // The whole std::vector approach is hacky af. ToDo change it maybe?
 template<typename T, size_t D, typename RootSchema, typename ToDecode>
 struct json_decode<schema::Array<T,D>, RootSchema, ToDecode> {
diff --git a/tests/codec-json.cpp b/tests/codec-json.cpp
index 926f550..e1b8b5c 100644
--- a/tests/codec-json.cpp
+++ b/tests/codec-json.cpp
@@ -213,7 +213,7 @@ SAW_TEST("String write and read"){
 	SAW_EXPECT(nat_str == "foo", "Incorrect value decoded");
 }
 
-SAW_TEST("Tuple write"){
+SAW_TEST("Tuple read and write"){
 	using namespace saw;
 	data<schema::TestTuple, encode::Native> native_tup;
 	data<schema::TestTuple, encode::Json> json_tup;
@@ -233,6 +233,13 @@ SAW_TEST("Tuple write"){
 	std::string enc_val = convert_to_string(json_tup.get_buffer());
 
 	SAW_EXPECT(enc_val == str_v, std::string{"Tuple not encoded correctly. Encoded: "} + enc_val + std::string{" Expected: "} + std::string{str_v});
+	native_tup = {};
+
+	eov = json_codec.decode(json_tup, native_tup);
+	SAW_EXPECT(eov.is_value(), "Decoding error");
+
+	SAW_EXPECT(native_tup.template get<0>() == "bar", "Invalid Value 0");
+	SAW_EXPECT(native_tup.template get<1>().get() == 34, "Invalid Value 1");
 }
 
 SAW_TEST("Array write"){
-- 
cgit v1.2.3