From 516f8637b8089ddc10bcd252a2c3db19f7561b4e Mon Sep 17 00:00:00 2001
From: Ryan Ofsky <ryan@ofsky.org>
Date: Fri, 26 Jul 2024 08:35:33 -0400
Subject: [PATCH] Add capnp serialization code for bitcoin types

- Add capnp ToBlob, ToArray, Wrap, Serialize, and Unserialize helper functions
- Add support for std::chrono::seconds capnp serialization
- Add support for util::Result capnp serialization
---
 src/ipc/capnp/common-types.h | 100 ++++++++++++++++++++++++++++++++++-
 src/ipc/capnp/common.capnp   |  20 +++++++
 2 files changed, 118 insertions(+), 2 deletions(-)

diff --git a/src/ipc/capnp/common-types.h b/src/ipc/capnp/common-types.h
index 934dae5faf3..d507b5dd65d 100644
--- a/src/ipc/capnp/common-types.h
+++ b/src/ipc/capnp/common-types.h
@@ -8,9 +8,12 @@
 #include <clientversion.h>
 #include <interfaces/types.h>
 #include <primitives/transaction.h>
+#include <protocol.h>
 #include <serialize.h>
 #include <streams.h>
 #include <univalue.h>
+#include <util/result.h>
+#include <util/translation.h>
 
 #include <cstddef>
 #include <mp/proxy-types.h>
@@ -28,12 +31,27 @@
 #include <mp/type-threadmap.h>
 #include <mp/type-vector.h>
 #include <type_traits>
+#include <unordered_set>
 #include <utility>
 
 namespace ipc {
 namespace capnp {
+//! Convert kj::ArrayPtr to base_blob.
+template <typename T>
+inline T ToBlob(const kj::ArrayPtr<const kj::byte>& array)
+{
+    return T({array.begin(), array.begin() + array.size()});
+}
+
+//! Convert base_blob to kj::ArrayPtr.
+template <typename T>
+inline kj::ArrayPtr<const kj::byte> ToArray(const T& blob)
+{
+    return {reinterpret_cast<const kj::byte*>(blob.data()), blob.size()};
+}
+
 //! Construct a ParamStream wrapping a data stream with serialization parameters
-//! needed to pass transaction objects between bitcoin processes.
+//! needed to pass transaction and address objects between bitcoin processes.
 //! In the future, more params may be added here to serialize other objects that
 //! require serialization parameters. Params should just be chosen to serialize
 //! objects completely and ensure that serializing and deserializing objects
@@ -42,7 +60,28 @@ namespace capnp {
 template <typename S>
 auto Wrap(S& s)
 {
-    return ParamsStream{s, TX_WITH_WITNESS};
+    return ParamsStream{s, TX_WITH_WITNESS, CAddress::V2_NETWORK};
+}
+
+//! Serialize bitcoin value.
+template <typename T>
+DataStream Serialize(const T& value)
+{
+    DataStream stream;
+    auto wrapper{Wrap(stream)};
+    value.Serialize(wrapper);
+    return stream;
+}
+
+//! Deserialize bitcoin value.
+template <typename T>
+T Unserialize(const kj::ArrayPtr<const kj::byte>& data)
+{
+    SpanReader stream{{data.begin(), data.end()}};
+    T value;
+    auto wrapper{Wrap(stream)};
+    value.Unserialize(wrapper);
+    return value;
 }
 
 //! Detect if type has a deserialize_type constructor, which is
@@ -127,6 +166,63 @@ decltype(auto) CustomReadField(TypeList<UniValue>, Priority<1>, InvokeContext& i
     });
 }
 
+//! Overload CustomBuildField and CustomReadField to serialize
+//! UniValue::type_error exceptions as text strings.
+template <typename Value, typename Output>
+void CustomBuildField(TypeList<UniValue::type_error>, Priority<1>, InvokeContext& invoke_context,
+                      Value&& value, Output&& output)
+{
+    BuildField(TypeList<std::string>(), invoke_context, output, std::string(value.what()));
+}
+
+template <typename Input, typename ReadDest>
+decltype(auto) CustomReadField(TypeList<UniValue::type_error>, Priority<1>, InvokeContext& invoke_context,
+                               Input&& input, ReadDest&& read_dest)
+{
+    read_dest.construct(ReadField(TypeList<std::string>(), invoke_context, input, mp::ReadDestTemp<std::string>()));
+}
+
+//! Overload CustomBuildField and CustomReadField to serialize util::Result
+//! return values as common.capnp Result and ResultVoid structs
+template <typename LocalType, typename Value, typename Output>
+void CustomBuildField(TypeList<util::Result<LocalType>>, Priority<1>, InvokeContext& invoke_context, Value&& value,
+                      Output&& output)
+{
+    auto result = output.init();
+    if (value) {
+        if constexpr (!std::is_same_v<LocalType, void>) {
+            using ValueAccessor = typename ProxyStruct<typename decltype(result)::Builds>::ValueAccessor;
+            BuildField(TypeList<LocalType>(), invoke_context, Make<StructField, ValueAccessor>(result), *value);
+        }
+    } else {
+        BuildField(TypeList<bilingual_str>(), invoke_context, Make<ValueField>(result.initError()),
+                   util::ErrorString(value));
+    }
+}
+
+template <typename LocalType, typename Input, typename ReadDest>
+decltype(auto) CustomReadField(TypeList<util::Result<LocalType>>, Priority<1>, InvokeContext& invoke_context,
+                               Input&& input, ReadDest&& read_dest)
+{
+    auto result = input.get();
+    if (result.hasError()) {
+        bilingual_str error;
+        ReadField(mp::TypeList<bilingual_str>(), invoke_context, mp::Make<mp::ValueField>(result.getError()),
+                    mp::ReadDestUpdate(error));
+        read_dest.construct(util::Error{std::move(error)});
+    } else {
+        if constexpr (!std::is_same_v<LocalType, void>) {
+            assert (result.hasValue());
+            ReadField(mp::TypeList<LocalType>(), invoke_context, mp::Make<mp::ValueField>(result.getValue()),
+                mp::ReadDestEmplace(
+                    mp::TypeList<LocalType>(), [&](auto&&... args) -> auto& {
+                        return *read_dest.construct(LocalType{std::forward<decltype(args)>(args)...});
+                    }));
+        } else {
+            read_dest.construct();
+        }
+    }
+}
 } // namespace mp
 
 #endif // BITCOIN_IPC_CAPNP_COMMON_TYPES_H
diff --git a/src/ipc/capnp/common.capnp b/src/ipc/capnp/common.capnp
index b3359f3f07b..691fa80f4d5 100644
--- a/src/ipc/capnp/common.capnp
+++ b/src/ipc/capnp/common.capnp
@@ -14,3 +14,23 @@ struct BlockRef $Proxy.wrap("interfaces::BlockRef") {
     hash @0 :Data;
     height @1 :Int32;
 }
+
+struct BilingualStr $Proxy.wrap("bilingual_str") {
+    original @0 :Text;
+    translated @1 :Text;
+}
+
+struct Result(Value) {
+    value @0 :Value;
+    error @1: BilingualStr;
+}
+
+# Wrapper for util::Result<void>
+struct ResultVoid(Value) {
+    error @0: BilingualStr;
+}
+
+struct Pair(Key, Value) {
+    key @0 :Key;
+    value @1 :Value;
+}