system/zbus: Port the Zephyr zbus message bus to NuttX

examples/zbus/CMakeLists.txt

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+# ##############################################################################
+# apps/examples/zbus/CMakeLists.txt
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more contributor
+# license agreements.  See the NOTICE file distributed with this work for
+# additional information regarding copyright ownership.  The ASF licenses this
+# file to you under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License.  You may obtain a copy of
+# the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations under
+# the License.
+#
+# ##############################################################################
+
+if(CONFIG_EXAMPLES_ZBUS)
+  nuttx_add_application(
+    NAME
+    ${CONFIG_EXAMPLES_ZBUS_PROGNAME}
+    SRCS
+    zbus_main.c
+    STACKSIZE
+    ${CONFIG_EXAMPLES_ZBUS_STACKSIZE}
+    PRIORITY
+    ${CONFIG_EXAMPLES_ZBUS_PRIORITY})
+endif()

examples/zbus/Kconfig

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+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config EXAMPLES_ZBUS
+	tristate "ZBus example"
+	default n
+	depends on ZBUS
+	---help---
+		Enable the zbus message bus example.
+
+if EXAMPLES_ZBUS
+
+config EXAMPLES_ZBUS_PROGNAME
+	string "Program name"
+	default "zbus"
+
+config EXAMPLES_ZBUS_PRIORITY
+	int "ZBus example task priority"
+	default 100
+
+config EXAMPLES_ZBUS_STACKSIZE
+	int "ZBus example stack size"
+	default DEFAULT_TASK_STACKSIZE
+
+endif

examples/zbus/Make.defs

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+############################################################################
+# apps/examples/zbus/Make.defs
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+############################################################################
+
+ifneq ($(CONFIG_EXAMPLES_ZBUS),)
+CONFIGURED_APPS += $(APPDIR)/examples/zbus
+endif

examples/zbus/Makefile

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+############################################################################
+# apps/examples/zbus/Makefile
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+############################################################################
+
+include $(APPDIR)/Make.defs
+
+# ZBus example built-in application info
+
+PROGNAME  = $(CONFIG_EXAMPLES_ZBUS_PROGNAME)
+PRIORITY  = $(CONFIG_EXAMPLES_ZBUS_PRIORITY)
+STACKSIZE = $(CONFIG_EXAMPLES_ZBUS_STACKSIZE)
+MODULE    = $(CONFIG_EXAMPLES_ZBUS)
+
+MAINSRC = zbus_main.c
+
+include $(APPDIR)/Application.mk

examples/zbus/zbus_main.c

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+/****************************************************************************
+ * apps/examples/zbus/zbus_main.c
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <pthread.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <system/zbus.h>
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct acc_msg
+{
+  int x;
+  int y;
+  int z;
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static void listener_callback(const struct zbus_channel *chan);
+
+/****************************************************************************
+ * Channel and observer definitions
+ ****************************************************************************/
+
+ZBUS_LISTENER_DEFINE(acc_listener, listener_callback);
+ZBUS_SUBSCRIBER_DEFINE(acc_subscriber, 4);
+
+ZBUS_CHAN_DEFINE(acc_chan,                       /* Name */
+                 struct acc_msg,                 /* Message type */
+                 NULL,                           /* Validator */
+                 NULL,                           /* User data */
+                 ZBUS_OBSERVERS(acc_listener,    /* Observers */
+                                acc_subscriber),
+                 ZBUS_MSG_INIT(.x = 0, .y = 0, .z = 0));
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static void listener_callback(const struct zbus_channel *chan)
+{
+  const struct acc_msg *msg = zbus_chan_const_msg(chan);
+
+  printf("zbus:  listener: x=%d y=%d z=%d\n", msg->x, msg->y, msg->z);
+}
+
+static void *subscriber_thread(void *arg)
+{
+  const struct zbus_channel *chan;
+  struct acc_msg msg;
+  int i;
+
+  for (i = 0; i < 5; i++)
+    {
+      if (zbus_sub_wait(&acc_subscriber, &chan, 2000) != 0)
+        {
+          printf("zbus:  subscriber: timeout!\n");
+          continue;
+        }
+
+      if (chan == &acc_chan)
+        {
+          zbus_chan_read(chan, &msg, 500);
+          printf("zbus:  subscriber: x=%d y=%d z=%d\n",
+                 msg.x, msg.y, msg.z);
+        }
+    }
+
+  return NULL;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+int main(int argc, char *argv[])
+{
+  struct acc_msg msg;
+  pthread_t thread;
+  int ret;
+  int i;
+
+  printf("zbus: publishing 5 messages to acc_chan\n");
+
+  ret = pthread_create(&thread, NULL, subscriber_thread, NULL);
+  if (ret != 0)
+    {
+      printf("zbus: could not create subscriber thread: %d\n", ret);
+      return 1;
+    }
+
+  for (i = 1; i <= 5; i++)
+    {
+      msg.x = i;
+      msg.y = i * 10;
+      msg.z = i * 100;
+
+      ret = zbus_chan_pub(&acc_chan, &msg, 1000);
+      if (ret != 0)
+        {
+          printf("zbus: publish error: %d\n", ret);
+        }
+
+      /* Mask the listener notifications on the third message to
+       * demonstrate the notification mask API.
+       */
+
+      if (i == 3)
+        {
+          zbus_obs_set_chan_notification_mask(&acc_listener, &acc_chan,
+                                              true);
+          printf("zbus: listener masked\n");
+        }
+      else if (i == 4)
+        {
+          zbus_obs_set_chan_notification_mask(&acc_listener, &acc_chan,
+                                              false);
+          printf("zbus: listener unmasked\n");
+        }
+
+      usleep(100 * 1000);
+    }
+
+  pthread_join(thread, NULL);
+
+  printf("zbus: done\n");
+
+  return 0;
+}