bt: Fix adapter methods

Took a while to figure out how to return an empty value for these
methods. Combination of withNoReply() and our own Void instance
did it.

1 files changed, 29 insertions, 10 deletions

diff --git a/src/bt.cc b/src/bt.cc
index 0881859..b8879c6 100644
--- a/src/bt.cc
+++ b/src/bt.cc
@@ -21,11 +21,30 @@
 #include <sdbus-c++/ProxyInterfaces.h>
 #include <sdbus-c++/StandardInterfaces.h>
 #include <sdbus-c++/Types.h>
+#include <sdbus-c++/TypeTraits.h>
 #include <sdbus-c++/VTableItems.h>
 #include <string>
 #include <utility>
 #include <vector>
 
+namespace {
+
+// Cannot get sdbus::Result to work with void, so this is the workaround.
+struct Void {
+  static Void const kInstance;
+};
+
+Void const Void::kInstance;
+
+sdbus::Message& operator<<(sdbus::Message& msg, const Void& /* ignored */) {
+  return msg;
+}
+
+}  // namespace
+
+template <>
+struct sdbus::signature_of<Void> : sdbus::signature_of<void> {};
+
 namespace bt {
 
 namespace {
@@ -629,8 +648,8 @@ class AgentObject {
                 }),
             sdbus::registerMethod("RequestConfirmation")
                 .withInputParamNames("device", "passkey")
-                .withOutputParamNames("result")
-                .implementedAs([this](sdbus::Result<sdbus::Variant>&& result,
+                .withNoReply()
+                .implementedAs([this](sdbus::Result<Void>&& result,
                                       sdbus::ObjectPath const& device,
                                       uint32_t passkey) {
                   cancel_pending();
@@ -640,7 +659,7 @@ class AgentObject {
                         if (!pending_confirm_.has_value())
                           return;
                         if (ok) {
-                          pending_confirm_->returnResults({});
+                          pending_confirm_->returnResults(Void::kInstance);
                         } else {
                           pending_confirm_->returnError(
                               sdbus::Error{kErrorRejected});
@@ -650,8 +669,8 @@ class AgentObject {
                 }),
             sdbus::registerMethod("RequestAuthorization")
                 .withInputParamNames("device")
-                .withOutputParamNames("result")
-                .implementedAs([this](sdbus::Result<sdbus::Variant>&& result,
+                .withNoReply()
+                .implementedAs([this](sdbus::Result<Void>&& result,
                                       sdbus::ObjectPath const& device) {
                   cancel_pending();
                   pending_confirm_ = std::move(result);
@@ -659,7 +678,7 @@ class AgentObject {
                     if (!pending_confirm_.has_value())
                       return;
                     if (ok) {
-                      pending_confirm_->returnResults({});
+                      pending_confirm_->returnResults(Void::kInstance);
                     } else {
                       pending_confirm_->returnError(
                           sdbus::Error{kErrorRejected});
@@ -669,8 +688,8 @@ class AgentObject {
                 }),
             sdbus::registerMethod("AuthorizeService")
                 .withInputParamNames("device", "uuid")
-                .withOutputParamNames("result")
-                .implementedAs([this](sdbus::Result<sdbus::Variant>&& result,
+                .withNoReply()
+                .implementedAs([this](sdbus::Result<Void>&& result,
                                       sdbus::ObjectPath const& device,
                                       std::string const& uuid) {
                   cancel_pending();
@@ -680,7 +699,7 @@ class AgentObject {
                         if (!pending_confirm_.has_value())
                           return;
                         if (ok) {
-                          pending_confirm_->returnResults({});
+                          pending_confirm_->returnResults(Void::kInstance);
                         } else {
                           pending_confirm_->returnError(
                               sdbus::Error{kErrorRejected});
@@ -722,7 +741,7 @@ class AgentObject {
 
   std::optional<sdbus::Result<std::string>> pending_pincode_;
   std::optional<sdbus::Result<uint32_t>> pending_passkey_;
-  std::optional<sdbus::Result<sdbus::Variant>> pending_confirm_;
+  std::optional<sdbus::Result<Void>> pending_confirm_;
 };
 
 class ManagerImpl : public Manager, public IManager, looper::Hook {