[RSDK-10923] Add IsHoldingSomething to Gripper API

Author: gvaradarajan

src/viam/sdk/components/gripper.hpp

@@ -5,6 +5,7 @@
 
 #include <string>
 
+#include <viam/sdk/common/proto_convert.hpp>
 #include <viam/sdk/resource/stoppable.hpp>
 
 namespace viam {
@@ -20,6 +21,13 @@ namespace sdk {
 /// specific gripper implementations. This class cannot be used on its own.
 class Gripper : public Component, public Stoppable {
    public:
+    /// @struct holding_status
+    /// @brief whether the gripper is holding something (along with other contextual info)
+    struct holding_status {
+        bool is_holding_something;
+        ProtoStruct meta;
+    };
+
     /// @brief Open the gripper.
     inline void open() {
         return open({});
@@ -40,6 +48,17 @@ class Gripper : public Component, public Stoppable {
     /// @return bool indicating if the gripper grabbed something.
     virtual bool grab(const ProtoStruct& extra) = 0;
 
+    /// @brief Reports whether the gripper is holding onto a object (alongside other information).
+    /// @return holding_status (see `holding_status` struct for more info).
+    inline holding_status is_holding_something() {
+        return holding_status({});
+    }
+
+    /// @brief Reports whether the gripper is holding onto a object (alongside other information).
+    /// @param extra Any additional arguments to the method.
+    /// @return holding_status (see `holding_status` struct for more info).
+    virtual holding_status is_holding_something(const ProtoStruct& extra) = 0;
+
     /// @brief Reports if the gripper is in motion.
     virtual bool is_moving() = 0;
 

src/viam/sdk/components/private/gripper_client.cpp

@@ -26,6 +26,23 @@ bool GripperClient::grab(const ProtoStruct& extra) {
     });
 }
 
+Gripper::holding_status GripperClient::is_holding_something(const ProtoStruct& extra) {
+    return make_client_helper(this, *stub_, &StubType::IsHoldingSomething)
+        .with(extra)
+        .invoke([](auto& response) {
+            Gripper::holding_status holding_status;
+            holding_status.is_holding_something = response.is_holding_something();
+            if response
+                .has_meta() {
+                    holding_status.meta = from_proto(response.meta());
+                }
+            else {
+                holding_status.meta = {};
+            }
+            return holding_status;
+        });
+}
+
 bool GripperClient::is_moving() {
     return make_client_helper(this, *stub_, &StubType::IsMoving).invoke([](auto& response) {
         return response.is_moving();

src/viam/sdk/components/private/gripper_client.hpp

@@ -25,6 +25,7 @@ class GripperClient : public Gripper {
 
     void open(const ProtoStruct& extra) override;
     bool grab(const ProtoStruct& extra) override;
+    Gripper::holding_status is_holding_something(const ProtoStruct& extra) override;
     void stop(const ProtoStruct& extra) override;
     bool is_moving() override;
     ProtoStruct do_command(const ProtoStruct& command) override;

src/viam/sdk/components/private/gripper_server.cpp

@@ -26,6 +26,18 @@ ::grpc::Status GripperServer::Grab(
     });
 }
 
+::grpc::Status GripperServer::IsHoldingSomething(
+    ::grpc::ServerContext*,
+    const ::viam::component::gripper::v1::IsHoldingSomethingRequest* request,
+    ::viam::component::gripper::v1::IsHoldingSomethingResponse* response) noexcept {
+    return make_service_helper<Gripper>(
+        "GripperServer::IsHoldingSomething", this, request)([&](auto& helper, auto& gripper) {
+        Gripper::holding_status res = gripper->is_holding_something(helper.getExtra());
+        response->set_is_holding_something(res.is_holding_something);
+        *(response->mutable_meta()) = to_proto(res.meta);
+    });
+}
+
 ::grpc::Status GripperServer::Stop(::grpc::ServerContext*,
                                    const ::viam::component::gripper::v1::StopRequest* request,
                                    ::viam::component::gripper::v1::StopResponse*) noexcept {

src/viam/sdk/components/private/gripper_server.hpp

@@ -34,6 +34,11 @@ class GripperServer : public ResourceServer,
                         const ::viam::component::gripper::v1::StopRequest* request,
                         ::viam::component::gripper::v1::StopResponse* response) noexcept override;
 
+    ::grpc::Status IsHoldingSomething(
+        ::grpc::ServerContext* context,
+        const ::viam::component::gripper::v1::IsHoldingSomethingRequest* request,
+        ::viam::component::gripper::v1::IsHoldingSomethingResponse* response) noexcept override;
+
     ::grpc::Status IsMoving(
         ::grpc::ServerContext* context,
         const ::viam::component::gripper::v1::IsMovingRequest* request,

src/viam/sdk/tests/mocks/mock_gripper.cpp

@@ -28,6 +28,13 @@ bool MockGripper::is_moving() {
     return false;
 }
 
+Gripper::holding_status MockGripper::is_holding_something(const ProtoStruct&) {
+    Gripper::holding_status res;
+    res.is_holding_something = false;
+    res.meta = {};
+    return res;
+}
+
 ProtoStruct MockGripper::do_command(const ProtoStruct& command) {
     return (peek_command = command);
 }

src/viam/sdk/tests/mocks/mock_gripper.hpp

@@ -17,6 +17,8 @@ class MockGripper : public sdk::Gripper {
 
     void open(const sdk::ProtoStruct& extra) override;
     bool grab(const sdk::ProtoStruct& extra) override;
+    Gripper::holding_status MockGripper::is_holding_something(
+        const sdk::ProtoStruct& extra) override;
     void stop(const sdk::ProtoStruct& extra) override;
     bool is_moving() override;
     sdk::ProtoStruct do_command(const sdk::ProtoStruct& command) override;