[rcl_action] Add function to check if goal can be transitioned to CANCELING (#325)

* [rcl_action] Add function for checking if goal can be transitioned to CANCELING

Add unit tests for the new function rcl_action_goal_handle_is_cancelable(), as well as rcl_action_goal_handle_is_active().

rcl_action/include/rcl_action/goal_handle.h

@@ -202,15 +202,37 @@ rcl_action_goal_handle_get_status(
  * Lock-Free          | Yes
  *
  * \param[in] goal_handle struct containing the goal and metadata
- * \return `true` if a goal is in one of the following states: ACCEPTED, EXECUTING, or CANCELING, or
+ * \return `true` if the goal is in one of the following states: ACCEPTED, EXECUTING, or CANCELING, or
- * \return `false` otherwise, also
+ * \return `false` if the goal handle pointer is invalid, or
- * \return `false` if the goal handle pointer is invalid
+ * \return `false` otherwise
 */
 RCL_ACTION_PUBLIC
 RCL_WARN_UNUSED
 bool
 rcl_action_goal_handle_is_active(const rcl_action_goal_handle_t * goal_handle);
 
+/// Check if a goal can be transitioned to CANCELING in its current state.
+/**
+ * This is a non-blocking call.
+ *
+ * <hr>
+ * Attribute          | Adherence
+ * ------------------ | -------------
+ * Allocates Memory   | No
+ * Thread-Safe        | No
+ * Uses Atomics       | No
+ * Lock-Free          | Yes
+ *
+ * \param[in] goal_handle struct containing the goal and metadata
+ * \return `true` if the goal can be transitioned to CANCELING from its current state, or
+ * \return `false` if the goal handle pointer is invalid, or
+ * \return `false` otherwise
+*/
+RCL_ACTION_PUBLIC
+RCL_WARN_UNUSED
+bool
+rcl_action_goal_handle_is_cancelable(const rcl_action_goal_handle_t * goal_handle);
+
 /// Check if a rcl_action_goal_handle_t is valid.
 /**
  * This is a non-blocking call.
@@ -229,8 +251,9 @@ rcl_action_goal_handle_is_active(const rcl_action_goal_handle_t * goal_handle);
  * Lock-Free          | Yes
  *
  * \param[in] goal_handle struct to evaluate as valid or not
- * \return `true` if the goal handle is valid, `false` otherwise, also
+ * \return `true` if the goal handle is valid, or
- * \return `false` if the goal handle pointer is null
+ * \return `false` if the goal handle pointer is null, or
+ * \return `false` otherwise
  */
 RCL_ACTION_PUBLIC
 RCL_WARN_UNUSED

rcl_action/src/rcl_action/goal_handle.c

@@ -137,6 +137,18 @@ rcl_action_goal_handle_is_active(const rcl_action_goal_handle_t * goal_handle)
   }
 }
 
+bool
+rcl_action_goal_handle_is_cancelable(const rcl_action_goal_handle_t * goal_handle)
+{
+  if (!rcl_action_goal_handle_is_valid(goal_handle)) {
+    return false;  // error message is set
+  }
+  // Check if the state machine reports a cancel event is valid
+  rcl_action_goal_state_t state = rcl_action_transition_goal_state(
+    goal_handle->impl->state, GOAL_EVENT_CANCEL);
+  return GOAL_STATE_CANCELING == state;
+}
+
 bool
 rcl_action_goal_handle_is_valid(const rcl_action_goal_handle_t * goal_handle)
 {

rcl_action/test/rcl_action/test_goal_handle.cpp

@@ -15,7 +15,7 @@
 
 #include <sstream>
 #include <string>
-#include <utility>
+#include <tuple>
 #include <vector>
 
 #include "rcl_action/goal_handle.h"
@@ -156,8 +156,9 @@ TEST(TestGoalHandle, test_goal_handle_update_state_invalid)
   rcl_reset_error();
 }
 
-using EventStatePair = std::pair<rcl_action_goal_event_t, rcl_action_goal_state_t>;
+using EventStateActiveCancelableTuple =
-using StateTransitionSequence = std::vector<EventStatePair>;
+  std::tuple<rcl_action_goal_event_t, rcl_action_goal_state_t, bool, bool>;
+using StateTransitionSequence = std::vector<EventStateActiveCancelableTuple>;
 const std::vector<std::string> event_strs = {
   "EXECUTE", "CANCEL", "SET_SUCCEEDED", "SET_ABORTED", "SET_CANCELED"};
 
@@ -169,8 +170,8 @@ public:
     const testing::TestParamInfo<StateTransitionSequence> & info)
   {
     std::stringstream result;
-    for (const EventStatePair & event_state : info.param) {
+    for (const EventStateActiveCancelableTuple & event_state : info.param) {
-      result << "_" << event_strs[event_state.first];
+      result << "_" << event_strs[std::get<0>(event_state)];
     }
     return result.str();
   }
@@ -216,15 +217,22 @@ TEST_P(TestGoalHandleStateTransitionSequence, test_goal_handle_state_transitions
 
   // Walk through state transitions
   rcl_ret_t ret;
-  for (const EventStatePair & event_state : this->test_sequence) {
+  for (const EventStateActiveCancelableTuple & event_state : this->test_sequence) {
-    ret = rcl_action_update_goal_state(&this->goal_handle, event_state.first);
+    rcl_action_goal_event_t goal_event;
-    const rcl_action_goal_state_t & expected_state = event_state.second;
+    rcl_action_goal_state_t expected_goal_state;
-    if (GOAL_STATE_UNKNOWN == expected_state) {
+    bool expected_is_active;
+    bool expected_is_cancelable;
+    std::tie(goal_event, expected_goal_state, expected_is_active, expected_is_cancelable) =
+      event_state;
+    ret = rcl_action_update_goal_state(&this->goal_handle, goal_event);
+    if (GOAL_STATE_UNKNOWN == expected_goal_state) {
       EXPECT_EQ(ret, RCL_RET_ACTION_GOAL_EVENT_INVALID);
       continue;
     }
     EXPECT_EQ(ret, RCL_RET_OK);
-    expect_state_eq(expected_state);
+    expect_state_eq(expected_goal_state);
+    EXPECT_EQ(expected_is_active, rcl_action_goal_handle_is_active(&this->goal_handle));
+    EXPECT_EQ(expected_is_cancelable, rcl_action_goal_handle_is_cancelable(&this->goal_handle));
   }
 }
 
@@ -232,40 +240,40 @@ TEST_P(TestGoalHandleStateTransitionSequence, test_goal_handle_state_transitions
 // Note, each sequence starts in the ACCEPTED state
 const StateTransitionSequence valid_state_transition_sequences[] = {
   {
-    {GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING},
+    std::make_tuple(GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING, true, true),
-    {GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING},
+    std::make_tuple(GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING, true, false),
-    {GOAL_EVENT_SET_CANCELED, GOAL_STATE_CANCELED},
+    std::make_tuple(GOAL_EVENT_SET_CANCELED, GOAL_STATE_CANCELED, false, false),
   },
   {
-    {GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING},
+    std::make_tuple(GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING, true, true),
-    {GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING},
+    std::make_tuple(GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING, true, false),
-    {GOAL_EVENT_SET_SUCCEEDED, GOAL_STATE_SUCCEEDED},
+    std::make_tuple(GOAL_EVENT_SET_SUCCEEDED, GOAL_STATE_SUCCEEDED, false, false),
   },
   {
-    {GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING},
+    std::make_tuple(GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING, true, true),
-    {GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING},
+    std::make_tuple(GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING, true, false),
-    {GOAL_EVENT_SET_ABORTED, GOAL_STATE_ABORTED},
+    std::make_tuple(GOAL_EVENT_SET_ABORTED, GOAL_STATE_ABORTED, false, false),
   },
   {
-    {GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING},
+    std::make_tuple(GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING, true, true),
-    {GOAL_EVENT_SET_SUCCEEDED, GOAL_STATE_SUCCEEDED},
+    std::make_tuple(GOAL_EVENT_SET_SUCCEEDED, GOAL_STATE_SUCCEEDED, false, false),
   },
   {
-    {GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING},
+    std::make_tuple(GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING, true, true),
-    {GOAL_EVENT_SET_ABORTED, GOAL_STATE_ABORTED},
+    std::make_tuple(GOAL_EVENT_SET_ABORTED, GOAL_STATE_ABORTED, false, false),
   },
   {
-    {GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING},
+    std::make_tuple(GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING, true, false),
-    {GOAL_EVENT_SET_CANCELED, GOAL_STATE_CANCELED},
+    std::make_tuple(GOAL_EVENT_SET_CANCELED, GOAL_STATE_CANCELED, false, false),
   },
   {
-    {GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING},
+    std::make_tuple(GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING, true, false),
-    {GOAL_EVENT_SET_ABORTED, GOAL_STATE_ABORTED},
+    std::make_tuple(GOAL_EVENT_SET_ABORTED, GOAL_STATE_ABORTED, false, false),
   },
   // This is an odd case, but valid nonetheless
   {
-    {GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING},
+    std::make_tuple(GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING, true, false),
-    {GOAL_EVENT_SET_SUCCEEDED, GOAL_STATE_SUCCEEDED},
+    std::make_tuple(GOAL_EVENT_SET_SUCCEEDED, GOAL_STATE_SUCCEEDED, false, false),
   },
 };
 
@@ -277,27 +285,27 @@ INSTANTIATE_TEST_CASE_P(
 
 const StateTransitionSequence invalid_state_transition_sequences[] = {
   {
-    {GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING},
+    std::make_tuple(GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING, true, true),
-    {GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING},
+    std::make_tuple(GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING, true, false),
-    {GOAL_EVENT_EXECUTE, GOAL_STATE_UNKNOWN},
+    std::make_tuple(GOAL_EVENT_EXECUTE, GOAL_STATE_UNKNOWN, false, false),
   },
   {
-    {GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING},
+    std::make_tuple(GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING, true, true),
-    {GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING},
+    std::make_tuple(GOAL_EVENT_CANCEL, GOAL_STATE_CANCELING, true, false),
-    {GOAL_EVENT_CANCEL, GOAL_STATE_UNKNOWN},
+    std::make_tuple(GOAL_EVENT_CANCEL, GOAL_STATE_UNKNOWN, false, false),
   },
   {
-    {GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING},
+    std::make_tuple(GOAL_EVENT_EXECUTE, GOAL_STATE_EXECUTING, true, true),
-    {GOAL_EVENT_EXECUTE, GOAL_STATE_UNKNOWN},
+    std::make_tuple(GOAL_EVENT_EXECUTE, GOAL_STATE_UNKNOWN, false, false),
   },
   {
-    {GOAL_EVENT_SET_CANCELED, GOAL_STATE_UNKNOWN},
+    std::make_tuple(GOAL_EVENT_SET_CANCELED, GOAL_STATE_UNKNOWN, false, false),
   },
   {
-    {GOAL_EVENT_SET_SUCCEEDED, GOAL_STATE_UNKNOWN},
+    std::make_tuple(GOAL_EVENT_SET_SUCCEEDED, GOAL_STATE_UNKNOWN, false, false),
   },
   {
-    {GOAL_EVENT_SET_ABORTED, GOAL_STATE_UNKNOWN},
+    std::make_tuple(GOAL_EVENT_SET_ABORTED, GOAL_STATE_UNKNOWN, false, false),
   },
 };