Import of the watch repository from Pebble

src/fw/applib/plugin_service.c

@@ -0,0 +1,159 @@
+/*
+ * 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.
+ */
+
+#include "event_service_client.h"
+#include "applib/applib_malloc.auto.h"
+#include "plugin_service.h"
+#include "plugin_service_private.h"
+#include "syscall/syscall.h"
+
+#include "process_state/app_state/app_state.h"
+#include "process_state/worker_state/worker_state.h"
+#include "system/logging.h"
+#include "system/passert.h"
+
+// ---------------------------------------------------------------------------------------------------------------
+// Get our state variables
+static PluginServiceState* prv_get_state(PebbleTask task) {
+  if (task == PebbleTask_Unknown) {
+    task = pebble_task_get_current();
+  }
+  if (task == PebbleTask_App) {
+    return app_state_get_plugin_service();
+  } else {
+    PBL_ASSERTN(task == PebbleTask_Worker);
+    return worker_state_get_plugin_service();
+  }
+}
+
+
+// ---------------------------------------------------------------------------------------------------------------
+// Lookup the plugin service index from the UUID. We store the index in the event structure instead of the UUID
+//  so that we have payload room.
+static uint16_t prv_get_service_index(Uuid *uuid) {
+  return sys_event_service_get_plugin_service_index(uuid);
+}
+
+
+// ---------------------------------------------------------------------------------------------------------------
+// Used by list_find to locate the handler for a specfic service index.
+static bool prv_service_filter(ListNode *node, void *tp) {
+  PluginServiceEntry *info = (PluginServiceEntry *)node;
+  uint16_t service_idx = (uint16_t)(uintptr_t)tp;
+  return (info->service_index == service_idx);
+}
+
+
+// ---------------------------------------------------------------------------------------------------------------
+// Callback provided to the app_event_service. All events of type PEBBLE_PLUGIN_SERVICE_EVENT that get sent to
+// this task trigger this callback. From here, we look up which user-supplied callback corresponds to the
+// service index stored in the event structure and then pass control to that user-supplied callback.
+static void prv_handle_event_service_event(PebbleEvent *e, void *context) {
+  PluginServiceState *state = prv_get_state(PebbleTask_Unknown);
+  uint16_t service_index = e->plugin_service.service_index;
+
+  ListNode *found;
+  ListNode *list = &state->subscribed_services;
+  found = list_find(list, prv_service_filter, (void*)(uintptr_t)service_index);
+  if (!found) {
+    return;
+  }
+
+  // Call the handler provided by the client
+  PluginServiceEntry *entry = (PluginServiceEntry *)found;
+  entry->handler(e->plugin_service.type, &e->plugin_service.data);
+}
+
+
+// ---------------------------------------------------------------------------------------------------------------
+// Subscribe to a specific plug-in service by uuid.
+bool plugin_service_subscribe(Uuid *uuid, PluginServiceHandler handler) {
+  PluginServiceState *state = prv_get_state(PebbleTask_Unknown);
+  uint16_t service_index = prv_get_service_index(uuid);
+
+  ListNode *list = &state->subscribed_services;
+  if (list_find(list, prv_service_filter, (void*)(uintptr_t)service_index)) {
+    PBL_LOG(LOG_LEVEL_DEBUG, "Plug service handler already subscribed");
+    return false;
+  }
+
+  // Add to handlers list
+  PluginServiceEntry *entry = applib_type_zalloc(PluginServiceEntry);
+  if (!entry) {
+    PBL_LOG(LOG_LEVEL_ERROR, "OOM in plugin_service_subscribe");
+    return false;
+  }
+  entry->service_index = service_index;
+  entry->handler = handler;
+  list_append(list, &entry->list_node);
+
+  // Subscribe to the app event service if we haven't already
+  if (!state->subscribed_to_app_event_service) {
+    state->subscribed_to_app_event_service = true;
+    event_service_client_subscribe(&state->event_service_info);
+  }
+  return true;
+}
+
+
+// ---------------------------------------------------------------------------------------------------------------
+// Unsubscribe from a specific plug-in service by uuid.
+bool plugin_service_unsubscribe(Uuid *uuid) {
+  PluginServiceState *state = prv_get_state(PebbleTask_Unknown);
+  uint16_t service_index = prv_get_service_index(uuid);
+
+  ListNode *found;
+  ListNode *list = &state->subscribed_services;
+  found = list_find(list, prv_service_filter, (void*)(uintptr_t)service_index);
+  if (!found) {
+    PBL_LOG(LOG_LEVEL_DEBUG, "Plug service handler already unsubscribed");
+    return true;
+  }
+
+  list_remove(found, NULL, NULL);
+  applib_free(found);
+  return true;
+}
+
+
+// ---------------------------------------------------------------------------------------------------------------
+// Send an event to all registered subscribers of the given plugin service identified by UUID.
+void plugin_service_send_event(Uuid *uuid, uint8_t type, PluginEventData *data) {
+  uint16_t service_index = prv_get_service_index(uuid);
+
+  PebbleEvent event = {
+    .type = PEBBLE_PLUGIN_SERVICE_EVENT,
+    .plugin_service = {
+        .service_index = service_index,
+        .type = type,
+        .data = *data
+    },
+  };
+  sys_send_pebble_event_to_kernel(&event);
+}
+
+
+// ---------------------------------------------------------------------------------------------------------------
+// Init our state variables.
+void plugin_service_state_init(PluginServiceState *state) {
+  *state = (PluginServiceState) {
+    .event_service_info = {
+        .type = PEBBLE_PLUGIN_SERVICE_EVENT,
+        .handler = &prv_handle_event_service_event,
+    },
+  };
+}
+