loggerd: eliminate recursion from handle_encoder_msg (#33453)

* refactor handle_encoder_msg

* removing the recursion only

---------

Co-authored-by: Adeeb Shihadeh <adeebshihadeh@gmail.com>

system/loggerd/loggerd.cc

@@ -64,51 +64,18 @@ struct RemoteEncoder {
   bool seen_first_packet = false;
 };
 
-int handle_encoder_msg(LoggerdState *s, Message *msg, std::string &name, struct RemoteEncoder &re, const EncoderInfo &encoder_info) {
-  int bytes_count = 0;
-
-  // extract the message
-  capnp::FlatArrayMessageReader cmsg(kj::ArrayPtr<capnp::word>((capnp::word *)msg->getData(), msg->getSize() / sizeof(capnp::word)));
-  auto event = cmsg.getRoot<cereal::Event>();
+size_t write_encode_data(LoggerdState *s, cereal::Event::Reader event, RemoteEncoder &re, const EncoderInfo &encoder_info) {
   auto edata = (event.*(encoder_info.get_encode_data_func))();
   auto idx = edata.getIdx();
   auto flags = idx.getFlags();
 
-  // encoderd can have started long before loggerd
-  if (!re.seen_first_packet) {
-    re.seen_first_packet = true;
-    re.encoderd_segment_offset = idx.getSegmentNum();
-    LOGD("%s: has encoderd offset %d", name.c_str(), re.encoderd_segment_offset);
-  }
-  int offset_segment_num = idx.getSegmentNum() - re.encoderd_segment_offset;
-
-  if (offset_segment_num == s->logger.segment()) {
-    // loggerd is now on the segment that matches this packet
-
-    // if this is a new segment, we close any possible old segments, move to the new, and process any queued packets
-    if (re.current_segment != s->logger.segment()) {
-      if (re.recording) {
-        re.writer.reset();
-        re.recording = false;
-      }
-      re.current_segment = s->logger.segment();
-      re.marked_ready_to_rotate = false;
-      // we are in this segment now, process any queued messages before this one
-      if (!re.q.empty()) {
-        for (auto &qmsg : re.q) {
-          bytes_count += handle_encoder_msg(s, qmsg, name, re, encoder_info);
-        }
-        re.q.clear();
-      }
-    }
-
   // if we aren't recording yet, try to start, since we are in the correct segment
   if (!re.recording) {
     if (flags & V4L2_BUF_FLAG_KEYFRAME) {
       // only create on iframe
       if (re.dropped_frames) {
         // this should only happen for the first segment, maybe
-          LOGW("%s: dropped %d non iframe packets before init", name.c_str(), re.dropped_frames);
+        LOGW("%s: dropped %d non iframe packets before init", encoder_info.publish_name, re.dropped_frames);
         re.dropped_frames = 0;
       }
       // if we aren't actually recording, don't create the writer
@@ -125,9 +92,8 @@ int handle_encoder_msg(LoggerdState *s, Message *msg, std::string &name, struct
     } else {
       // this is a sad case when we aren't recording, but don't have an iframe
       // nothing we can do but drop the frame
-        delete msg;
       ++re.dropped_frames;
-        return bytes_count;
+      return 0;
     }
   }
 
@@ -147,9 +113,48 @@ int handle_encoder_msg(LoggerdState *s, Message *msg, std::string &name, struct
   (evt.*(encoder_info.set_encode_idx_func))(idx);
   auto new_msg = bmsg.toBytes();
   s->logger.write((uint8_t *)new_msg.begin(), new_msg.size(), true);  // always in qlog?
-    bytes_count += new_msg.size();
+  return new_msg.size();
+}
+
+int handle_encoder_msg(LoggerdState *s, Message *msg, std::string &name, struct RemoteEncoder &re, const EncoderInfo &encoder_info) {
+  int bytes_count = 0;
+
+  // extract the message
+  capnp::FlatArrayMessageReader cmsg(kj::ArrayPtr<capnp::word>((capnp::word *)msg->getData(), msg->getSize() / sizeof(capnp::word)));
+  auto event = cmsg.getRoot<cereal::Event>();
+  auto edata = (event.*(encoder_info.get_encode_data_func))();
+  auto idx = edata.getIdx();
+
+  // encoderd can have started long before loggerd
+  if (!re.seen_first_packet) {
+    re.seen_first_packet = true;
+    re.encoderd_segment_offset = idx.getSegmentNum();
+    LOGD("%s: has encoderd offset %d", name.c_str(), re.encoderd_segment_offset);
+  }
+  int offset_segment_num = idx.getSegmentNum() - re.encoderd_segment_offset;
 
-    // free the message, we used it
+  if (offset_segment_num == s->logger.segment()) {
+    // loggerd is now on the segment that matches this packet
+
+    // if this is a new segment, we close any possible old segments, move to the new, and process any queued packets
+    if (re.current_segment != s->logger.segment()) {
+      if (re.recording) {
+        re.writer.reset();
+        re.recording = false;
+      }
+      re.current_segment = s->logger.segment();
+      re.marked_ready_to_rotate = false;
+      // we are in this segment now, process any queued messages before this one
+      if (!re.q.empty()) {
+        for (auto qmsg : re.q) {
+          capnp::FlatArrayMessageReader reader({(capnp::word *)qmsg->getData(), qmsg->getSize() / sizeof(capnp::word)});
+          bytes_count += write_encode_data(s, reader.getRoot<cereal::Event>(), re, encoder_info);
+          delete qmsg;
+        }
+        re.q.clear();
+      }
+    }
+    bytes_count += write_encode_data(s, event, re, encoder_info);
     delete msg;
   } else if (offset_segment_num > s->logger.segment()) {
     // encoderd packet has a newer segment, this means encoderd has rolled over