Import of the watch repository from Pebble

src/fw/applib/compass_service_stub.c

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed 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 CAPABILITY_HAS_MAGNETOMETER
+#error "Use fw/applib/compass_service.c instead if we don't have a magnetometer"
+#endif
+
+//! @file compass_service_stub.c
+//!
+//! Implements the compass_service for devices that don't actually have a compass. See
+//! fw/applib/compass_service.c for the real implementation for boards that do have a compass.
+
+#include "compass_service.h"
+
+#include "process_management/process_manager.h"
+
+//! @return which status value we should use to indicate we have no compass
+static CompassStatus prv_get_status(void) {
+  if (process_manager_compiled_with_legacy2_sdk() ||
+      process_manager_compiled_with_legacy3_sdk()) {
+    // This value is new in 4.x. Use the old CompassStatusDataInvalid value instead for old apps
+    // that may not know how to handle the previously undefined status.
+    return CompassStatusDataInvalid;
+  }
+
+  return CompassStatusUnavailable;
+}
+
+int compass_service_peek(CompassHeadingData *data) {
+  *data = (CompassHeadingData) {
+    .compass_status = prv_get_status()
+  };
+
+  return 0;
+}
+
+int compass_service_set_heading_filter(CompassHeading filter) {
+  // Just ignore the filter, we're not going to call the handler regularly anyway.
+  return 0;
+}
+
+void compass_service_subscribe(CompassHeadingHandler handler) {
+  CompassHeadingData data = {
+    .compass_status = prv_get_status()
+  };
+
+  // Call the handler once to indicate status
+  handler(data);
+}
+
+void compass_service_unsubscribe(void) {
+  // Nothing to do because we never handle the subscribe in the first place
+}