refactor: refine extension stop flow

core/include_internal/ten_runtime/extension_thread/extension_thread.h

@@ -30,6 +30,9 @@ typedef enum TEN_EXTENSION_THREAD_STATE {
   TEN_EXTENSION_THREAD_STATE_CREATING_EXTENSIONS,
   TEN_EXTENSION_THREAD_STATE_NORMAL,
   TEN_EXTENSION_THREAD_STATE_PREPARE_TO_CLOSE,
+
+  // All extensions of this extension thread are closed, and removed from this
+  // extension thread.
   TEN_EXTENSION_THREAD_STATE_CLOSED,
 } TEN_EXTENSION_THREAD_STATE;
 

core/src/ten_runtime/extension/extension.c

@@ -797,13 +797,8 @@ static void ten_extension_flush_all_pending_msgs(ten_extension_t *self) {
   TEN_ASSERT(ten_extension_check_integrity(self, true),
              "Invalid use of extension %p.", self);
 
-  // The developer expects that on_start() will execute before all on_cmd()
-  // events. Therefore, after on_start() has been executed, there is no need
-  // to wait for on_start_done() before sending all previously buffered
-  // messages into the extension.
-
   // Flush the previously got messages, which are received before
-  // on_start_done(), into the extension.
+  // on_init_done(), into the extension.
   ten_extension_thread_t *extension_thread = self->extension_thread;
   ten_list_foreach (&extension_thread->pending_msgs, iter) {
     ten_shared_ptr_t *msg = ten_smart_ptr_listnode_get(iter.node);
@@ -819,7 +814,7 @@ static void ten_extension_flush_all_pending_msgs(ten_extension_t *self) {
   }
 
   // Flush the previously got messages, which are received before
-  // on_start_done(), into the extension.
+  // on_init_done(), into the extension.
   ten_list_foreach (&self->pending_msgs, iter) {
     ten_shared_ptr_t *msg = ten_smart_ptr_listnode_get(iter.node);
     TEN_ASSERT(msg, "Should not happen.");
@@ -841,6 +836,11 @@ void ten_extension_on_start(ten_extension_t *self) {
   if (self->on_start) {
     self->on_start(self, self->ten_env);
 
+    // The developer expects that on_start() will execute before all on_cmd()
+    // events. Therefore, after on_start() has been executed, there is no need
+    // to wait for on_start_done() before sending all previously buffered
+    // messages into the extension.
+
     ten_extension_flush_all_pending_msgs(self);
   } else {
     ten_extension_flush_all_pending_msgs(self);

core/src/ten_runtime/extension/msg_handling.c

@@ -70,26 +70,32 @@ void ten_extension_handle_in_msg(ten_extension_t *self, ten_shared_ptr_t *msg) {
 
   bool delete_msg = false;
 
-  // - During on_init() and on_deinit(), there should be no interaction with
-  //   other extensions.
-  // - During on_start() and on_stop(), it is possible to send messages to other
-  //   extensions and receive cmd_result for that message.
+  // - During on_configure(), on_init() and on_deinit(), the extension should
+  //   not receive any messages, because it is not ready to handle any messages.
+  // - In other time periods, it is possible to receive and send messages to
+  //   other extensions and receive cmd result.
   //
   // The messages, from other extensions, sent to this extension will be
-  // delivered to this extension only after its on_start_done(). Therefore, all
-  // messages sent to this extension before on_start_done() will be queued until
-  // on_start_done() is triggered. On the other hand, the cmd result of the
-  // command sent by this extension in on_start() can be delivered to this
-  // extension before its on_start_done().
+  // delivered to this extension only after its on_start(). Therefore, all
+  // messages sent to this extension before on_start() will be queued until
+  // on_start() is triggered. On the other hand, the cmd result of the
+  // command sent by this extension in any time can be delivered to this
+  // extension before its on_start().
 
   if (self->state < TEN_EXTENSION_STATE_ON_START &&
       !ten_msg_is_cmd_result(msg)) {
-    // The extension is not started, and the msg is not a cmd result, so
+    // The extension is not initialized, and the msg is not a cmd result, so
     // cache the msg to the pending list.
     ten_list_push_smart_ptr_back(&self->pending_msgs, msg);
     goto done;
   }
 
+  if (self->state >= TEN_EXTENSION_STATE_ON_DEINIT) {
+    // The extension is in its de-initialization phase, and is not ready to
+    // handle any messages, so drop any messages.
+    goto done;
+  }
+
   bool msg_is_cmd_result = false;
 
   // Because 'commands' has 'results', TEN will perform some bookkeeping for
@@ -147,7 +153,7 @@ void ten_extension_handle_in_msg(ten_extension_t *self, ten_shared_ptr_t *msg) {
         // command (if the IN path still exists) when on_cmd_done().
         //
         // TODO(Xilin): Currently, there is no mechanism for auto return, so the
-        // relevant logic code should be able to be disabled.
+        // relevant codes should be able to be disabled.
         ten_extension_cache_cmd_result_to_in_path_for_auto_return(self, msg);
 
         delete_msg = true;

core/src/ten_runtime/extension_thread/msg_interface/common.c

@@ -110,50 +110,36 @@ static void ten_extension_thread_handle_in_msg_task(void *self_, void *arg) {
   TEN_ASSERT(msg && ten_msg_check_integrity(msg), "Invalid argument.");
   TEN_ASSERT(ten_msg_get_dest_cnt(msg) == 1, "Should not happen.");
 
-  if (ten_msg_get_type(msg) == TEN_MSG_TYPE_CMD_RESULT) {
-    if (ten_extension_thread_get_state(self) <=
-        TEN_EXTENSION_THREAD_STATE_PREPARE_TO_CLOSE) {
-      // The receipt of a result is definitely because some extension of this
-      // extension thread previously sent out a command. As long as the
-      // extension can issue a command, the corresponding result must be
-      // delivered to and processed by the respective extension.
-      ten_extension_thread_handle_in_msg_sync(self, msg);
-    } else {
-      // Discard this cmd result.
-    }
-  } else {
-    switch (ten_extension_thread_get_state(self)) {
-      case TEN_EXTENSION_THREAD_STATE_INIT:
-      case TEN_EXTENSION_THREAD_STATE_CREATING_EXTENSIONS: {
+  switch (ten_extension_thread_get_state(self)) {
+    case TEN_EXTENSION_THREAD_STATE_INIT:
+    case TEN_EXTENSION_THREAD_STATE_CREATING_EXTENSIONS:
 #if defined(_DEBUG)
-        ten_msg_dump(msg, NULL,
-                     "A message (^m) comes when extension thread (%p) is in "
-                     "state (%d)",
-                     self, ten_extension_thread_get_state(self));
+      ten_msg_dump(msg, NULL,
+                   "A message (^m) comes when extension thread (%p) is in "
+                   "state (%d)",
+                   self, ten_extension_thread_get_state(self));
 #endif
 
-        // At this stage, the extensions have not been created yet, so any
-        // received messages are placed into a `pending_msgs` list. Once the
-        // extensions are created, the messages will be delivered to the
-        // corresponding extensions.
-        ten_list_push_smart_ptr_back(&self->pending_msgs, msg);
-        break;
-      }
+      // At this stage, the extensions have not been created yet, so any
+      // received messages are placed into a `pending_msgs` list. Once the
+      // extensions are created, the messages will be delivered to the
+      // corresponding extensions.
+      ten_list_push_smart_ptr_back(&self->pending_msgs, msg);
+      break;
 
-      case TEN_EXTENSION_THREAD_STATE_NORMAL:
-      case TEN_EXTENSION_THREAD_STATE_PREPARE_TO_CLOSE:
-        ten_extension_thread_handle_in_msg_sync(self, msg);
-        break;
+    case TEN_EXTENSION_THREAD_STATE_NORMAL:
+    case TEN_EXTENSION_THREAD_STATE_PREPARE_TO_CLOSE:
+      ten_extension_thread_handle_in_msg_sync(self, msg);
+      break;
 
-      case TEN_EXTENSION_THREAD_STATE_CLOSED:
-        // All the extensions of the extension thread have been closed, so
-        // discard all received messages directly.
-        break;
+    case TEN_EXTENSION_THREAD_STATE_CLOSED:
+      // All extensions are removed from this extension thread, so the only
+      // thing we can do is to discard this cmd result.
+      break;
 
-      default:
-        TEN_ASSERT(0, "Should not happen.");
-        break;
-    }
+    default:
+      TEN_ASSERT(0, "Should not happen.");
+      break;
   }
 
   ten_shared_ptr_destroy(msg);