Introduce executors new spin_for method, replace spin_until_future_complete with spin_until_complete. (ros2#1821)

 * Introduce spin_for method.
 * Introduce spin_until_complete.
 * Deprecate spin_until_future_complete.
 * Replace usage of deprecated method.
 * Update unit-tests.

Signed-off-by: Hubert Liberacki <[email protected]>

Author: hliberacki

rclcpp/include/rclcpp/client.hpp

@@ -579,11 +579,11 @@ class Client : public ClientBase
   /// Send a request to the service server.
   /**
    * This method returns a `FutureAndRequestId` instance
-   * that can be passed to Executor::spin_until_future_complete() to
+   * that can be passed to Executor::spin_until_complete() to
    * wait until it has been completed.
    *
    * If the future never completes,
-   * e.g. the call to Executor::spin_until_future_complete() times out,
+   * e.g. the call to Executor::spin_until_complete() times out,
    * Client::remove_pending_request() must be called to clean the client internal state.
    * Not doing so will make the `Client` instance to use more memory each time a response is not
    * received from the service server.
@@ -592,7 +592,7 @@ class Client : public ClientBase
    * auto future = client->async_send_request(my_request);
    * if (
    *   rclcpp::FutureReturnCode::TIMEOUT ==
-   *   executor->spin_until_future_complete(future, timeout))
+   *   executor->spin_until_complete(future, timeout))
    * {
    *   client->remove_pending_request(future);
    *   // handle timeout

rclcpp/include/rclcpp/executor.hpp

@@ -26,6 +26,7 @@
 #include <mutex>
 #include <string>
 #include <vector>
+#include <type_traits>
 
 #include "rcl/guard_condition.h"
 #include "rcl/wait.h"
@@ -319,6 +320,50 @@ class Executor
   virtual void
   spin_once(std::chrono::nanoseconds timeout = std::chrono::nanoseconds(-1));
 
+  /// Spin (blocking) until the condition is complete, it times out waiting,
+  /// or rclcpp is interrupted.
+  /**
+   * \param[in] future The condition which can be callable or future type to wait on.
+   *   If this function returns SUCCESS, the future can be
+   *   accessed without blocking (though it may still throw an exception).
+   * \param[in] timeout Optional timeout parameter, which gets passed to Executor::spin_node_once.
+   *   `-1` is block forever, `0` is non-blocking.
+   *   If the time spent inside the blocking loop exceeds this timeout, return a TIMEOUT return
+   *   code.
+   * \return The return code, one of `SUCCESS`, `INTERRUPTED`, or `TIMEOUT`.
+   */
+  template<typename Condition, typename DurationT = std::chrono::milliseconds>
+  FutureReturnCode spin_until_complete(
+    const Condition & condition,
+    DurationT timeout = DurationT(-1))
+  {
+    if constexpr (std::is_invocable_v<Condition>) {
+      using RetT = std::invoke_result_t<Condition>;
+      static_assert(
+        std::is_same_v<bool, RetT>,
+        "Conditional callable has to return boolean type");
+      return spin_until_complete_impl(condition, timeout);
+    } else {
+      auto checkFuture = [&condition]() {
+          return condition.wait_for(std::chrono::seconds(0)) ==
+                 std::future_status::ready;
+        };
+      return spin_until_complete_impl(checkFuture, timeout);
+    }
+  }
+
+  /// spin (blocking) for given amount of duration.
+  /**
+   * \param[in] duration gets passed to Executor::spin_node_once,
+   *   spins the executor for given duration.
+   */
+  template<typename DurationT>
+  void
+  spin_for(DurationT duration)
+  {
+    (void)spin_until_complete([]() {return false;}, duration);
+  }
+
   /// Spin (blocking) until the future is complete, it times out waiting, or rclcpp is interrupted.
   /**
    * \param[in] future The future to wait on. If this function returns SUCCESS, the future can be
@@ -330,57 +375,13 @@ class Executor
    * \return The return code, one of `SUCCESS`, `INTERRUPTED`, or `TIMEOUT`.
    */
   template<typename FutureT, typename TimeRepT = int64_t, typename TimeT = std::milli>
+  [[deprecated("use spin_until_complete(const Condition & condition, DurationT timeout) instead")]]
   FutureReturnCode
   spin_until_future_complete(
     const FutureT & future,
     std::chrono::duration<TimeRepT, TimeT> timeout = std::chrono::duration<TimeRepT, TimeT>(-1))
   {
-    // TODO(wjwwood): does not work recursively; can't call spin_node_until_future_complete
-    // inside a callback executed by an executor.
-
-    // Check the future before entering the while loop.
-    // If the future is already complete, don't try to spin.
-    std::future_status status = future.wait_for(std::chrono::seconds(0));
-    if (status == std::future_status::ready) {
-      return FutureReturnCode::SUCCESS;
-    }
-
-    auto end_time = std::chrono::steady_clock::now();
-    std::chrono::nanoseconds timeout_ns = std::chrono::duration_cast<std::chrono::nanoseconds>(
-      timeout);
-    if (timeout_ns > std::chrono::nanoseconds::zero()) {
-      end_time += timeout_ns;
-    }
-    std::chrono::nanoseconds timeout_left = timeout_ns;
-
-    if (spinning.exchange(true)) {
-      throw std::runtime_error("spin_until_future_complete() called while already spinning");
-    }
-    RCPPUTILS_SCOPE_EXIT(this->spinning.store(false); );
-    while (rclcpp::ok(this->context_) && spinning.load()) {
-      // Do one item of work.
-      spin_once_impl(timeout_left);
-
-      // Check if the future is set, return SUCCESS if it is.
-      status = future.wait_for(std::chrono::seconds(0));
-      if (status == std::future_status::ready) {
-        return FutureReturnCode::SUCCESS;
-      }
-      // If the original timeout is < 0, then this is blocking, never TIMEOUT.
-      if (timeout_ns < std::chrono::nanoseconds::zero()) {
-        continue;
-      }
-      // Otherwise check if we still have time to wait, return TIMEOUT if not.
-      auto now = std::chrono::steady_clock::now();
-      if (now >= end_time) {
-        return FutureReturnCode::TIMEOUT;
-      }
-      // Subtract the elapsed time from the original timeout.
-      timeout_left = std::chrono::duration_cast<std::chrono::nanoseconds>(end_time - now);
-    }
-
-    // The future did not complete before ok() returned false, return INTERRUPTED.
-    return FutureReturnCode::INTERRUPTED;
+    return spin_until_complete(future, timeout);
   }
 
   /// Cancel any running spin* function, causing it to return.
@@ -560,6 +561,48 @@ class Executor
   virtual void
   spin_once_impl(std::chrono::nanoseconds timeout);
 
+protected:
+  // Implementation details, used by spin_until_complete and spin_for.
+  // Previouse implementation of spin_until_future_complete.
+  template<typename Condition, typename DurationT>
+  FutureReturnCode spin_until_complete_impl(Condition condition, DurationT timeout)
+  {
+    auto end_time = std::chrono::steady_clock::now();
+    std::chrono::nanoseconds timeout_ns = std::chrono::duration_cast<std::chrono::nanoseconds>(
+      timeout);
+    if (timeout_ns > std::chrono::nanoseconds::zero()) {
+      end_time += timeout_ns;
+    }
+    std::chrono::nanoseconds timeout_left = timeout_ns;
+    if (spinning.exchange(true)) {
+      throw std::runtime_error("spin_until_complete() called while already spinning");
+    }
+    RCPPUTILS_SCOPE_EXIT(this->spinning.store(false); );
+    while (rclcpp::ok(this->context_) && spinning.load()) {
+      // Do one item of work.
+      spin_once_impl(timeout_left);
+
+      if (condition()) {
+        return FutureReturnCode::SUCCESS;
+      }
+      // If the original timeout is < 0, then this is blocking, never TIMEOUT.
+      if (timeout_ns < std::chrono::nanoseconds::zero()) {
+        continue;
+      }
+      // Otherwise check if we still have time to wait, return TIMEOUT if not.
+      auto now = std::chrono::steady_clock::now();
+      if (now >= end_time) {
+        return FutureReturnCode::TIMEOUT;
+      }
+      // Subtract the elapsed time from the original timeout.
+      timeout_left = std::chrono::duration_cast<std::chrono::nanoseconds>(end_time - now);
+    }
+
+    // The condition did not pass before ok() returned false, return INTERRUPTED.
+    return FutureReturnCode::INTERRUPTED;
+  }
+
+public:
   typedef std::map<rclcpp::node_interfaces::NodeBaseInterface::WeakPtr,
       const rclcpp::GuardCondition *,
       std::owner_less<rclcpp::node_interfaces::NodeBaseInterface::WeakPtr>>

rclcpp/include/rclcpp/executors.hpp

@@ -54,6 +54,50 @@ namespace executors
 using rclcpp::executors::MultiThreadedExecutor;
 using rclcpp::executors::SingleThreadedExecutor;
 
+/// Spin (blocking) until the conditon is complete, it times out waiting, or rclcpp is interrupted.
+/**
+ * \param[in] executor The executor which will spin the node.
+ * \param[in] node_ptr The node to spin.
+ * \param[in] condition The callable or future to wait on. If `SUCCESS`, the condition is safe to
+ *   access after this function
+ * \param[in] timeout Optional timeout parameter, which gets passed to
+ *   Executor::spin_node_once.
+ *   `-1` is block forever, `0` is non-blocking.
+ *   If the time spent inside the blocking loop exceeds this timeout, return a `TIMEOUT` return code.
+ * \return The return code, one of `SUCCESS`, `INTERRUPTED`, or `TIMEOUT`.
+ */
+template<typename Condition, typename DurationT = std::chrono::milliseconds>
+rclcpp::FutureReturnCode
+spin_node_until_complete(
+  rclcpp::Executor & executor,
+  rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
+  const Condition & condition,
+  DurationT timeout = DurationT(-1))
+{
+  // TODO(wjwwood): does not work recursively; can't call spin_node_until_complete
+  // inside a callback executed by an executor.
+  executor.add_node(node_ptr);
+  auto retcode = executor.spin_until_complete(condition, timeout);
+  executor.remove_node(node_ptr);
+  return retcode;
+}
+
+template<typename NodeT = rclcpp::Node, typename ConditionT,
+  typename DurationT = std::chrono::milliseconds>
+rclcpp::FutureReturnCode
+spin_node_until_complete(
+  rclcpp::Executor & executor,
+  std::shared_ptr<NodeT> node_ptr,
+  const ConditionT & condition,
+  DurationT timeout = DurationT(-1))
+{
+  return rclcpp::executors::spin_node_until_complete(
+    executor,
+    node_ptr->get_node_base_interface(),
+    condition,
+    timeout);
+}
+
 /// Spin (blocking) until the future is complete, it times out waiting, or rclcpp is interrupted.
 /**
  * \param[in] executor The executor which will spin the node.
@@ -67,31 +111,31 @@ using rclcpp::executors::SingleThreadedExecutor;
  * \return The return code, one of `SUCCESS`, `INTERRUPTED`, or `TIMEOUT`.
  */
 template<typename FutureT, typename TimeRepT = int64_t, typename TimeT = std::milli>
+[[deprecated("use spin_node_until_complete(Executor &,"
+                                           "node_interfaces::NodeBaseInterface::SharedPtr,"
+                                           "const Condition &, DurationT) instead")]]
 rclcpp::FutureReturnCode
 spin_node_until_future_complete(
   rclcpp::Executor & executor,
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
   const FutureT & future,
   std::chrono::duration<TimeRepT, TimeT> timeout = std::chrono::duration<TimeRepT, TimeT>(-1))
 {
-  // TODO(wjwwood): does not work recursively; can't call spin_node_until_future_complete
-  // inside a callback executed by an executor.
-  executor.add_node(node_ptr);
-  auto retcode = executor.spin_until_future_complete(future, timeout);
-  executor.remove_node(node_ptr);
-  return retcode;
+  return spin_until_complete(executor, node_ptr, future, timeout);
 }
 
 template<typename NodeT = rclcpp::Node, typename FutureT, typename TimeRepT = int64_t,
   typename TimeT = std::milli>
+[[deprecated("use spin_node_until_complete(Executor &, std::shared_ptr<NodeT>,"
+                                           "const Condition &, DurationT) instead")]]
 rclcpp::FutureReturnCode
 spin_node_until_future_complete(
   rclcpp::Executor & executor,
   std::shared_ptr<NodeT> node_ptr,
   const FutureT & future,
   std::chrono::duration<TimeRepT, TimeT> timeout = std::chrono::duration<TimeRepT, TimeT>(-1))
 {
-  return rclcpp::executors::spin_node_until_future_complete(
+  return rclcpp::executors::spin_node_until_complete(
     executor,
     node_ptr->get_node_base_interface(),
     future,
@@ -100,26 +144,52 @@ spin_node_until_future_complete(
 
 }  // namespace executors
 
+template<typename Condition, typename DurationT = std::chrono::milliseconds>
+rclcpp::FutureReturnCode
+spin_until_complete(
+  rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
+  const Condition & condition,
+  DurationT timeout = DurationT(-1))
+{
+  rclcpp::executors::SingleThreadedExecutor executor;
+  return executors::spin_node_until_complete<Condition>(executor, node_ptr, condition, timeout);
+}
+
+template<typename NodeT = rclcpp::Node, typename Condition,
+  typename DurationT = std::chrono::milliseconds>
+rclcpp::FutureReturnCode
+spin_until_complete(
+  std::shared_ptr<NodeT> node_ptr,
+  const Condition & condition,
+  DurationT timeout = DurationT(-1))
+{
+  return rclcpp::spin_until_complete(node_ptr->get_node_base_interface(), condition, timeout);
+}
+
 template<typename FutureT, typename TimeRepT = int64_t, typename TimeT = std::milli>
+[[deprecated("use spin_until_complete(node_interfaces::NodeBaseInterface::SharedPtr,"
+                                      "const Condition &,DurationT) instead")]]
 rclcpp::FutureReturnCode
 spin_until_future_complete(
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_ptr,
   const FutureT & future,
   std::chrono::duration<TimeRepT, TimeT> timeout = std::chrono::duration<TimeRepT, TimeT>(-1))
 {
   rclcpp::executors::SingleThreadedExecutor executor;
-  return executors::spin_node_until_future_complete<FutureT>(executor, node_ptr, future, timeout);
+  return executors::spin_node_until_complete<FutureT>(executor, node_ptr, future, timeout);
 }
 
 template<typename NodeT = rclcpp::Node, typename FutureT, typename TimeRepT = int64_t,
   typename TimeT = std::milli>
+[[deprecated("use spin_until_complete(std::shared_ptr<NodeT>, const Condition &,"
+                                      "DurationT) instead")]]
 rclcpp::FutureReturnCode
 spin_until_future_complete(
   std::shared_ptr<NodeT> node_ptr,
   const FutureT & future,
   std::chrono::duration<TimeRepT, TimeT> timeout = std::chrono::duration<TimeRepT, TimeT>(-1))
 {
-  return rclcpp::spin_until_future_complete(node_ptr->get_node_base_interface(), future, timeout);
+  return rclcpp::spin_until_complete(node_ptr->get_node_base_interface(), future, timeout);
 }
 
 }  // namespace rclcpp

rclcpp/include/rclcpp/future_return_code.hpp

@@ -23,7 +23,7 @@
 namespace rclcpp
 {
 
-/// Return codes to be used with spin_until_future_complete.
+/// Return codes to be used with spin_until_complete.
 /**
  * SUCCESS: The future is complete and can be accessed with "get" without blocking.
  *          This does not indicate that the operation succeeded; "get" may still throw an exception.

rclcpp/include/rclcpp/rclcpp.hpp

@@ -68,7 +68,7 @@
  * - Executors (responsible for execution of callbacks through a blocking spin):
  *   - rclcpp::spin()
  *   - rclcpp::spin_some()
- *   - rclcpp::spin_until_future_complete()
+ *   - rclcpp::spin_until_complete()
  *   - rclcpp::executors::SingleThreadedExecutor
  *   - rclcpp::executors::SingleThreadedExecutor::add_node()
  *   - rclcpp::executors::SingleThreadedExecutor::spin()