From d97669b8b9d68e7d511bf38bdad907fc7ee4e9a0 Mon Sep 17 00:00:00 2001
From: Michael Carlstrom <rmc@carlstrom.com>
Date: Wed, 7 Aug 2024 18:41:47 -0400
Subject: [PATCH] Creates PublisherHandle and updates publisher.py (#1310)

* PublisherHandle

Signed-off-by: Michael Carlstrom <rmc@carlstrom.com>

* create-publisher more generic

Signed-off-by: Michael Carlstrom <rmc@carlstrom.com>

---------

Signed-off-by: Michael Carlstrom <rmc@carlstrom.com>
Signed-off-by: Shane Loretz <sloretz@openrobotics.org>
Co-authored-by: Shane Loretz <sloretz@openrobotics.org>
---
 rclpy/rclpy/event_handler.py |  2 +-
 rclpy/rclpy/node.py          |  6 ++++-
 rclpy/rclpy/publisher.py     | 44 +++++++++++++++++++++++++++++++-----
 rclpy/rclpy/type_support.py  |  2 +-
 4 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/rclpy/rclpy/event_handler.py b/rclpy/rclpy/event_handler.py
index caad8f502..9bcd111c8 100644
--- a/rclpy/rclpy/event_handler.py
+++ b/rclpy/rclpy/event_handler.py
@@ -137,7 +137,7 @@ def __exit__(self, t, v, tb):
         """Mark event as not-in-use to allow destruction after waiting on it."""
         self.__event.__exit__(t, v, tb)
 
-    def destroy(self):
+    def destroy(self) -> None:
         self.__event.destroy_when_not_in_use()
 
 
diff --git a/rclpy/rclpy/node.py b/rclpy/rclpy/node.py
index d4b128f34..66c669ebb 100644
--- a/rclpy/rclpy/node.py
+++ b/rclpy/rclpy/node.py
@@ -113,6 +113,10 @@
 NodeNameNonExistentError = _rclpy.NodeNameNonExistentError
 
 
+class NodeHandle:
+    pass
+
+
 class Node:
     """
     A Node in the ROS graph.
@@ -1534,7 +1538,7 @@ def create_publisher(
         callback_group: Optional[CallbackGroup] = None,
         event_callbacks: Optional[PublisherEventCallbacks] = None,
         qos_overriding_options: Optional[QoSOverridingOptions] = None,
-        publisher_class: Type[Publisher] = Publisher,
+        publisher_class: Type[Publisher[MsgT]] = Publisher[MsgT],
     ) -> Publisher[MsgT]:
         """
         Create a new publisher.
diff --git a/rclpy/rclpy/publisher.py b/rclpy/rclpy/publisher.py
index 998e555d9..7a47ab5dc 100644
--- a/rclpy/rclpy/publisher.py
+++ b/rclpy/rclpy/publisher.py
@@ -13,10 +13,11 @@
 # limitations under the License.
 
 from types import TracebackType
-from typing import Generic, List, Optional, Type, TypeVar, Union
+from typing import Generic, List, Optional, Protocol, Type, TYPE_CHECKING, TypeVar, Union
 
 from rclpy.callback_groups import CallbackGroup
-from rclpy.duration import Duration
+from rclpy.destroyable import DestroyableType
+from rclpy.duration import Duration, DurationType
 from rclpy.event_handler import EventHandler, PublisherEventCallbacks
 from rclpy.impl.implementation_singleton import rclpy_implementation as _rclpy
 from rclpy.qos import QoSProfile
@@ -25,12 +26,43 @@
 # Left to support Legacy TypeVars.
 MsgType = TypeVar('MsgType')
 
+if TYPE_CHECKING:
+    from rclpy.node import NodeHandle
+
+
+class PublisherHandle(DestroyableType, Protocol[MsgT]):
+
+    def __init__(self, arg0: 'NodeHandle', arg1: Type[MsgT], arg2: str, arg3: object) -> None:
+        """Create PublisherHandle."""
+
+    @property
+    def pointer(self) -> int:
+        """Get the address of the entity as an integer."""
+
+    def get_logger_name(self) -> str:
+        """Get the name of the logger associated with the node of the publisher."""
+
+    def get_subscription_count(self) -> int:
+        """Count subscribers from a publisher."""
+
+    def get_topic_name(self) -> str:
+        """Retrieve the topic name from a Publisher."""
+
+    def publish(self, arg0: MsgT) -> None:
+        """Publish a message."""
+
+    def publish_raw(self, arg0: bytes) -> None:
+        """Publish a serialized message."""
+
+    def wait_for_all_acked(self, arg0: DurationType) -> bool:
+        """Wait until all published message data is acknowledged."""
+
 
 class Publisher(Generic[MsgT]):
 
     def __init__(
         self,
-        publisher_impl: _rclpy.Publisher,
+        publisher_impl: PublisherHandle[MsgT],
         msg_type: Type[MsgT],
         topic: str,
         qos_profile: QoSProfile,
@@ -86,10 +118,10 @@ def topic_name(self) -> str:
             return self.__publisher.get_topic_name()
 
     @property
-    def handle(self):
+    def handle(self) -> PublisherHandle[MsgT]:
         return self.__publisher
 
-    def destroy(self):
+    def destroy(self) -> None:
         """
         Destroy a container for a ROS publisher.
 
@@ -130,7 +162,7 @@ def wait_for_all_acked(self, timeout: Duration = Duration(seconds=-1)) -> bool:
         with self.handle:
             return self.__publisher.wait_for_all_acked(timeout._duration_handle)
 
-    def __enter__(self) -> 'Publisher':
+    def __enter__(self) -> 'Publisher[MsgT]':
         return self
 
     def __exit__(
diff --git a/rclpy/rclpy/type_support.py b/rclpy/rclpy/type_support.py
index f13ad8415..33ef95d9d 100644
--- a/rclpy/rclpy/type_support.py
+++ b/rclpy/rclpy/type_support.py
@@ -52,7 +52,7 @@ class Msg(Protocol, metaclass=MsgMetaClass):
     pass
 
 
-MsgT = TypeVar('MsgT', bound=Msg)
+MsgT = TypeVar('MsgT', bound=Msg, contravariant=True)
 
 SrvRequestT = TypeVar('SrvRequestT', bound=Msg)
 SrvResponseT = TypeVar('SrvResponseT', bound=Msg)