Add components. (#5)

build-root/Makefile

@@ -63,6 +63,7 @@ esp32-no-env: check-env
 build-host:
 	# Note that the 'host' is automatically added.
 	@cmake -E env \
+		"EXTERNAL_TOIT_LIB_DIRS=$(COMPONENTS)" \
 		$(MAKE) -C "$(TOIT_ROOT)" BUILD=$(BUILD_PATH)
 
 $(SDK_PATH)/bin/toit$(EXE_SUFFIX): build-host

components/echo/CMakeLists.txt

@@ -0,0 +1,5 @@
+# Copyright (C) 2024 Toitware ApS.
+# Use of this source code is governed by a Zero-Clause BSD license that can
+# be found in the LICENSE file.
+
+include("${CMAKE_CURRENT_LIST_DIR}/toit.cmake")

components/echo/echo.c

@@ -0,0 +1,90 @@
+// Copyright (C) 2024 Toitware ApS.
+// Use of this source code is governed by a Zero-Clause BSD license that can
+// be found in the LICENSE file.
+
+#include <toit/toit.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+/// A struct to hold the context of the external service.
+/// Typically, this would hold more data, but for this example, we only need
+/// the message context.
+typedef struct {
+  toit_msg_context_t* msg_context;
+} echo_service_t;
+
+/// @brief Called when the external message handler is created.
+/// @param user_data The user data passed to `toit_msg_add_handler`.
+/// @param context The context of the external message handler. Calls to
+///           `toit_msg_notify` and `toit_msg_remove_handler` need this context.
+/// @return TOIT_ERR_SUCCESS. The only allowed return value.
+static toit_err_t on_created(void* user_data, toit_msg_context_t* context) {
+  echo_service_t* echo_service = (echo_service_t*)user_data;
+  echo_service->msg_context = context;
+  return TOIT_ERR_SUCCESS;
+}
+
+/// @brief Called when a notification message is received.
+///
+/// Echoes the message back to the sender.
+/// Note that notifications are not required to be replied to.
+///
+/// @param user_data The user data passed to `toit_msg_add_handler`.
+/// @param sender The id of the sender.
+/// @param data The data of the message.
+/// @param length The length of the message.
+/// @return TOIT_ERR_SUCCESS. The only allowed return value.
+static toit_err_t on_message(void* user_data, int sender, void* data, int length) {
+  echo_service_t* echo_service = (echo_service_t*)user_data;
+  toit_msg_context_t* context = echo_service->msg_context;
+  if (toit_msg_notify(context, sender, data, length, true) != TOIT_ERR_SUCCESS) {
+    printf("unable to send\n");
+  }
+  return TOIT_ERR_SUCCESS;
+}
+
+/// @brief Called when an RPC request is received.
+///
+/// For every RPC request the service must reply through either `toit_msg_request_reply` or
+/// `toit_msg_request_fail`.
+///
+/// @param user_data The user data passed to `toit_msg_add_handler`.
+/// @param sender The id of the sender.
+/// @param function The function id of the request. For the echo service this is ignored.
+/// @param handle The handle to reply to the request. This handle must be provided to either
+///               `toit_msg_request_reply` or `toit_msg_request_fail`.
+/// @param data The data of the request.
+/// @param length The length of the request.
+/// @return TOIT_ERR_SUCCESS. The only allowed return value.
+static toit_err_t on_rpc_request(void* user_data, int sender, int function, toit_msg_request_handle_t handle, void* data, int length) {
+  if (toit_msg_request_reply(handle, data, length, true) != TOIT_ERR_SUCCESS) {
+    printf("unable to reply\n");
+  }
+  return TOIT_ERR_SUCCESS;
+}
+
+/// @brief Called when the external message handler is removed.
+///
+/// When this function is called, it is safe to free the user data.
+///
+/// @param user_data The user data passed to `toit_msg_add_handler`.
+/// @return TOIT_ERR_SUCCESS. The only allowed return value.
+static toit_err_t on_removed(void* user_data) {
+  free(user_data);
+  return TOIT_ERR_SUCCESS;
+}
+
+/// @brief  Register the external service.
+static void __attribute__((constructor)) init() {
+  echo_service_t* echo_service = (echo_service_t*)malloc(sizeof(echo_service_t));
+  echo_service->msg_context = NULL;
+  toit_msg_cbs_t cbs = {
+    .on_created = &on_created,
+    .on_message = &on_message,
+    .on_rpc_request = &on_rpc_request,
+    .on_removed = &on_removed,
+  };
+  toit_msg_add_handler("toitlang.org/demo-echo", echo_service, cbs);
+}

components/echo/echo.toit

@@ -0,0 +1,21 @@
+// Copyright (C) 2024 Toitware ApS.
+// Use of this source code is governed by a Zero-Clause BSD license that can
+// be found in the LICENSE file.
+
+/**
+Example code for communicating with the external echo service.
+*/
+
+import system.external
+
+FUNCTION-ID ::= 0
+
+main:
+  echo := external.Client.open "toitlang.org/demo-echo"
+  echo.set-on-notify:: print "Got message: $it.to-string"
+  echo.notify "Hello, world!"
+
+  response := echo.request FUNCTION-ID #[1, 2, 3]
+  print "Got response: $response"
+
+  echo.close

components/echo/toit.cmake

@@ -0,0 +1,13 @@
+# Copyright (C) 2024 Toitware ApS.
+# Use of this source code is governed by a Zero-Clause BSD license that can
+# be found in the LICENSE file.
+
+# Due to this function call being in a `toit.cmake` file, the library is also
+# compiled into the host executable. If this is not desired, then rename this
+# file or copy the content into the `CMakeLists.txt` file.
+
+idf_component_register(
+  REQUIRES toit
+  SRCS echo.c
+  WHOLE_ARCHIVE
+)