channels: refactor

2025-09-30 23:18:33 +00:00 · 2017-08-27 11:59:33 +02:00
parent 3717e2157f
commit 5215e3205a
17 changed files with 581 additions and 533 deletions
--- a/src/nvim/msgpack_rpc/channel.c
+++ b/src/nvim/msgpack_rpc/channel.c
@@ -11,6 +11,7 @@
 #include "nvim/api/private/helpers.h"
 #include "nvim/api/vim.h"
 #include "nvim/api/ui.h"
+#include "nvim/channel.h"
 #include "nvim/msgpack_rpc/channel.h"
 #include "nvim/msgpack_rpc/server.h"
 #include "nvim/event/loop.h"
@@ -40,47 +41,6 @@
 #define log_server_msg(...)
 #endif

-typedef enum {
-  kChannelTypeSocket,
-  kChannelTypeProc,
-  kChannelTypeStdio,
-  kChannelTypeInternal
-} ChannelType;
-
-typedef struct {
-  uint64_t request_id;
-  bool returned, errored;
-  Object result;
-} ChannelCallFrame;
-
-typedef struct {
-  uint64_t id;
-  size_t refcount;
-  PMap(cstr_t) *subscribed_events;
-  bool closed;
-  ChannelType type;
-  msgpack_unpacker *unpacker;
-  union {
-    Stream stream;  // bidirectional (socket)
-    Process *proc;
-    struct {
-      Stream in;
-      Stream out;
-    } std;
-  } data;
-  uint64_t next_request_id;
-  kvec_t(ChannelCallFrame *) call_stack;
-  MultiQueue *events;
-} Channel;
-
-typedef struct {
-  Channel *channel;
-  MsgpackRpcRequestHandler handler;
-  Array args;
-  uint64_t request_id;
-} RequestEvent;
-
-static PMap(uint64_t) *channels = NULL;
 static PMap(cstr_t) *event_strings = NULL;
 static msgpack_sbuffer out_buffer;

@@ -88,50 +48,32 @@ static msgpack_sbuffer out_buffer;
 # include "msgpack_rpc/channel.c.generated.h"
 #endif

-/// Initializes the module
-void channel_init(void)
+void rpc_init(void)
 {
  ch_before_blocking_events = multiqueue_new_child(main_loop.events);
-  channels = pmap_new(uint64_t)();
  event_strings = pmap_new(cstr_t)();
  msgpack_sbuffer_init(&out_buffer);
-  remote_ui_init();
 }

-/// Teardown the module
-void channel_teardown(void)
+
+void rpc_start(Channel *channel)
 {
-  if (!channels) {
-    return;
-  }
+  channel->is_rpc = true;
+  RpcState *rpc = &channel->rpc;
+  rpc->closed = false;
+  rpc->unpacker = msgpack_unpacker_new(MSGPACK_UNPACKER_INIT_BUFFER_SIZE);
+  rpc->subscribed_events = pmap_new(cstr_t)();
+  rpc->next_request_id = 1;
+  kv_init(rpc->call_stack);

-  Channel *channel;
+  Stream *in = channel_instream(channel);
+  Stream *out = channel_outstream(channel);

-  map_foreach_value(channels, channel, {
-    close_channel(channel);
-  });
-}
+  DLOG("rpc ch %" PRIu64 " in-stream=%p out-stream=%p", channel->id, in, out);

-/// Creates an API channel by starting a process and connecting to its
-/// stdin/stdout. stderr is handled by the job infrastructure.
-///
-/// @param argv The argument vector for the process. [consumed]
-/// @return The channel id (> 0), on success.
-///         0, on error.
-uint64_t channel_from_process(Process *proc, uint64_t id)
-{
-  Channel *channel = register_channel(kChannelTypeProc, id, proc->events);
-  incref(channel);  // process channels are only closed by the exit_cb
-  channel->data.proc = proc;
-
-  wstream_init(proc->in, 0);
-  rstream_init(proc->out, 0);
-  rstream_start(proc->out, receive_msgpack, channel);
-
-  DLOG("ch %" PRIu64 " in-stream=%p out-stream=%p", channel->id, proc->in,
-       proc->out);
-
-  return channel->id;
+  wstream_init(in, 0);
+  rstream_init(out, CHANNEL_BUFFER_SIZE);
+  rstream_start(out, receive_msgpack, channel);
 }

 /// Creates an API channel from a tcp/pipe socket connection
@@ -139,19 +81,15 @@ uint64_t channel_from_process(Process *proc, uint64_t id)
 /// @param watcher The SocketWatcher ready to accept the connection
 void channel_from_connection(SocketWatcher *watcher)
 {
-  Channel *channel = register_channel(kChannelTypeSocket, 0, NULL);
-  socket_watcher_accept(watcher, &channel->data.stream);
-  incref(channel);  // close channel only after the stream is closed
-  channel->data.stream.internal_close_cb = close_cb;
-  channel->data.stream.internal_data = channel;
-  wstream_init(&channel->data.stream, 0);
-  rstream_init(&channel->data.stream, CHANNEL_BUFFER_SIZE);
-  rstream_start(&channel->data.stream, receive_msgpack, channel);
-
-  DLOG("ch %" PRIu64 " in/out-stream=%p", channel->id,
-       &channel->data.stream);
+  Channel *channel = channel_alloc(kChannelStreamSocket);
+  socket_watcher_accept(watcher, &channel->stream.socket);
+  channel_incref(channel);  // close channel only after the stream is closed
+  channel->stream.socket.internal_close_cb = close_cb;
+  channel->stream.socket.internal_data = channel;
+  rpc_start(channel);
 }

+/// TODO: move to eval.c, also support bytes
 uint64_t channel_connect(bool tcp, const char *address,
                         int timeout, const char **error)
 {
@@ -165,34 +103,40 @@ uint64_t channel_connect(bool tcp, const char *address,
    xfree(path);
  }

-  Channel *channel = register_channel(kChannelTypeSocket, 0, NULL);
-  if (!socket_connect(&main_loop, &channel->data.stream,
+  Channel *channel = channel_alloc(kChannelStreamSocket);
+  if (!socket_connect(&main_loop, &channel->stream.socket,
                      tcp, address, timeout, error)) {
-    decref(channel);
+    channel_decref(channel);
    return 0;
  }

-  incref(channel);  // close channel only after the stream is closed
-  channel->data.stream.internal_close_cb = close_cb;
-  channel->data.stream.internal_data = channel;
-  wstream_init(&channel->data.stream, 0);
-  rstream_init(&channel->data.stream, CHANNEL_BUFFER_SIZE);
-  rstream_start(&channel->data.stream, receive_msgpack, channel);
+  channel_incref(channel);  // close channel only after the stream is closed
+  channel->stream.socket.internal_close_cb = close_cb;
+  channel->stream.socket.internal_data = channel;
+  rpc_start(channel);
  return channel->id;
 }

+static Channel *find_rpc_channel(uint64_t id)
+{
+  Channel *chan = find_channel(id);
+  if (!chan || !chan->is_rpc || chan->rpc.closed) {
+    return NULL;
+  }
+  return chan;
+}
+
 /// Publishes an event to a channel.
 ///
 /// @param id Channel id. 0 means "broadcast to all subscribed channels"
 /// @param name Event name (application-defined)
 /// @param args Array of event arguments
 /// @return True if the event was sent successfully, false otherwise.
-bool channel_send_event(uint64_t id, const char *name, Array args)
+bool rpc_send_event(uint64_t id, const char *name, Array args)
 {
  Channel *channel = NULL;

-  if (id && (!(channel = pmap_get(uint64_t)(channels, id))
-            || channel->closed)) {
+  if (id && (!(channel = find_rpc_channel(id)))) {
    api_free_array(args);
    return false;
  }
@@ -213,29 +157,30 @@ bool channel_send_event(uint64_t id, const char *name, Array args)
 /// @param args Array with method arguments
 /// @param[out] error True if the return value is an error
 /// @return Whatever the remote method returned
-Object channel_send_call(uint64_t id,
-                         const char *method_name,
-                         Array args,
-                         Error *err)
+Object rpc_send_call(uint64_t id,
+                     const char *method_name,
+                     Array args,
+                     Error *err)
 {
  Channel *channel = NULL;

-  if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
+  if (!(channel = find_rpc_channel(id))) {
    api_set_error(err, kErrorTypeException, "Invalid channel: %" PRIu64, id);
    api_free_array(args);
    return NIL;
  }

-  incref(channel);
-  uint64_t request_id = channel->next_request_id++;
+  channel_incref(channel);
+  RpcState *rpc = &channel->rpc;
+  uint64_t request_id = rpc->next_request_id++;
  // Send the msgpack-rpc request
  send_request(channel, request_id, method_name, args);

  // Push the frame
  ChannelCallFrame frame = { request_id, false, false, NIL };
-  kv_push(channel->call_stack, &frame);
+  kv_push(rpc->call_stack, &frame);
  LOOP_PROCESS_EVENTS_UNTIL(&main_loop, channel->events, -1, frame.returned);
-  (void)kv_pop(channel->call_stack);
+  (void)kv_pop(rpc->call_stack);

  if (frame.errored) {
    if (frame.result.type == kObjectTypeString) {
@@ -260,7 +205,7 @@ Object channel_send_call(uint64_t id,
    api_free_object(frame.result);
  }

-  decref(channel);
+  channel_decref(channel);

  return frame.errored ? NIL : frame.result;
 }
@@ -269,11 +214,11 @@ Object channel_send_call(uint64_t id,
 ///
 /// @param id The channel id
 /// @param event The event type string
-void channel_subscribe(uint64_t id, char *event)
+void rpc_subscribe(uint64_t id, char *event)
 {
  Channel *channel;

-  if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
+  if (!(channel = find_rpc_channel(id))) {
    abort();
  }

@@ -284,18 +229,18 @@ void channel_subscribe(uint64_t id, char *event)
    pmap_put(cstr_t)(event_strings, event_string, event_string);
  }

-  pmap_put(cstr_t)(channel->subscribed_events, event_string, event_string);
+  pmap_put(cstr_t)(channel->rpc.subscribed_events, event_string, event_string);
 }

 /// Unsubscribes to event broadcasts
 ///
 /// @param id The channel id
 /// @param event The event type string
-void channel_unsubscribe(uint64_t id, char *event)
+void rpc_unsubscribe(uint64_t id, char *event)
 {
  Channel *channel;

-  if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
+  if (!(channel = find_rpc_channel(id))) {
    abort();
  }

@@ -310,7 +255,7 @@ bool channel_close(uint64_t id)
 {
  Channel *channel;

-  if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
+  if (!(channel = find_rpc_channel(id))) {
    return false;
  }

@@ -322,24 +267,22 @@ bool channel_close(uint64_t id)
 /// Neovim
 void channel_from_stdio(void)
 {
-  Channel *channel = register_channel(kChannelTypeStdio, 0, NULL);
-  incref(channel);  // stdio channels are only closed on exit
+  Channel *channel = channel_alloc(kChannelStreamStdio);
+  channel_incref(channel);  // stdio channels are only closed on exit
  // read stream
-  rstream_init_fd(&main_loop, &channel->data.std.in, 0, CHANNEL_BUFFER_SIZE);
-  rstream_start(&channel->data.std.in, receive_msgpack, channel);
-  // write stream
-  wstream_init_fd(&main_loop, &channel->data.std.out, 1, 0);
+  rstream_init_fd(&main_loop, &channel->stream.stdio.in, 0, CHANNEL_BUFFER_SIZE);
+  wstream_init_fd(&main_loop, &channel->stream.stdio.out, 1, 0);

-  DLOG("ch %" PRIu64 " in-stream=%p out-stream=%p", channel->id,
-       &channel->data.std.in, &channel->data.std.out);
+  rpc_start(channel);
 }

 /// Creates a loopback channel. This is used to avoid deadlock
 /// when an instance connects to its own named pipe.
 uint64_t channel_create_internal(void)
 {
-  Channel *channel = register_channel(kChannelTypeInternal, 0, NULL);
-  incref(channel);  // internal channel lives until process exit
+  Channel *channel = channel_alloc(kChannelStreamInternal);
+  channel_incref(channel);  // internal channel lives until process exit
+  rpc_start(channel);
  return channel->id;
 }

@@ -347,8 +290,8 @@ void channel_process_exit(uint64_t id, int status)
 {
  Channel *channel = pmap_get(uint64_t)(channels, id);

-  channel->closed = true;
-  decref(channel);
+  // channel_decref(channel); remove??
+  channel->rpc.closed = true;
 }

 // rstream.c:read_event() invokes this as stream->read_cb().
@@ -356,7 +299,7 @@ static void receive_msgpack(Stream *stream, RBuffer *rbuf, size_t c,
                            void *data, bool eof)
 {
  Channel *channel = data;
-  incref(channel);
+  channel_incref(channel);

  if (eof) {
    close_channel(channel);
@@ -367,30 +310,19 @@ static void receive_msgpack(Stream *stream, RBuffer *rbuf, size_t c,
    goto end;
  }

-  if ((chan_wstream(channel) != NULL && chan_wstream(channel)->closed)
-      || (chan_rstream(channel) != NULL && chan_rstream(channel)->closed)) {
-    char buf[256];
-    snprintf(buf, sizeof(buf),
-             "ch %" PRIu64 ": stream closed unexpectedly. "
-             "closing channel",
-             channel->id);
-    call_set_error(channel, buf, WARN_LOG_LEVEL);
-    goto end;
-  }
-
  size_t count = rbuffer_size(rbuf);
-  DLOG("ch %" PRIu64 ": parsing %u bytes from msgpack Stream: %p",
+  DLOG("ch %" PRIu64 ": parsing %zu bytes from msgpack Stream: %p",
       channel->id, count, stream);

  // Feed the unpacker with data
-  msgpack_unpacker_reserve_buffer(channel->unpacker, count);
-  rbuffer_read(rbuf, msgpack_unpacker_buffer(channel->unpacker), count);
-  msgpack_unpacker_buffer_consumed(channel->unpacker, count);
+  msgpack_unpacker_reserve_buffer(channel->rpc.unpacker, count);
+  rbuffer_read(rbuf, msgpack_unpacker_buffer(channel->rpc.unpacker), count);
+  msgpack_unpacker_buffer_consumed(channel->rpc.unpacker, count);

  parse_msgpack(channel);

 end:
-  decref(channel);
+  channel_decref(channel);
 }

 static void parse_msgpack(Channel *channel)
@@ -400,8 +332,8 @@ static void parse_msgpack(Channel *channel)
  msgpack_unpack_return result;

  // Deserialize everything we can.
-  while ((result = msgpack_unpacker_next(channel->unpacker, &unpacked)) ==
-      MSGPACK_UNPACK_SUCCESS) {
+  while ((result = msgpack_unpacker_next(channel->rpc.unpacker, &unpacked)) ==
+         MSGPACK_UNPACK_SUCCESS) {
    bool is_response = is_rpc_response(&unpacked.data);
    log_client_msg(channel->id, !is_response, unpacked.data);

@@ -427,7 +359,7 @@ static void parse_msgpack(Channel *channel)
  if (result == MSGPACK_UNPACK_NOMEM_ERROR) {
    mch_errmsg(e_outofmem);
    mch_errmsg("\n");
-    decref(channel);
+    channel_decref(channel);
    preserve_exit();
  }

@@ -492,7 +424,7 @@ static void handle_request(Channel *channel, msgpack_object *request)
  evdata->handler = handler;
  evdata->args = args;
  evdata->request_id = request_id;
-  incref(channel);
+  channel_incref(channel);
  if (handler.async) {
    bool is_get_mode = handler.fn == handle_nvim_get_mode;

@@ -530,66 +462,30 @@ static void on_request_event(void **argv)
    api_free_object(result);
  }
  api_free_array(args);
-  decref(channel);
+  channel_decref(channel);
  xfree(e);
  api_clear_error(&error);
 }

-/// Returns the Stream that a Channel writes to.
-static Stream *chan_wstream(Channel *chan)
-{
-  switch (chan->type) {
-    case kChannelTypeSocket:
-      return &chan->data.stream;
-    case kChannelTypeProc:
-      return chan->data.proc->in;
-    case kChannelTypeStdio:
-      return &chan->data.std.out;
-    case kChannelTypeInternal:
-      return NULL;
-  }
-  abort();
-}
-
-/// Returns the Stream that a Channel reads from.
-static Stream *chan_rstream(Channel *chan)
-{
-  switch (chan->type) {
-    case kChannelTypeSocket:
-      return &chan->data.stream;
-    case kChannelTypeProc:
-      return chan->data.proc->out;
-    case kChannelTypeStdio:
-      return &chan->data.std.in;
-    case kChannelTypeInternal:
-      return NULL;
-  }
-  abort();
-}
-
-
 static bool channel_write(Channel *channel, WBuffer *buffer)
 {
-  bool success = false;
+  bool success;

-  if (channel->closed) {
+  if (channel->rpc.closed) {
    wstream_release_wbuffer(buffer);
    return false;
  }

-  switch (channel->type) {
-    case kChannelTypeSocket:
-    case kChannelTypeProc:
-    case kChannelTypeStdio:
-      success = wstream_write(chan_wstream(channel), buffer);
-      break;
-    case kChannelTypeInternal:
-      incref(channel);
-      CREATE_EVENT(channel->events, internal_read_event, 2, channel, buffer);
-      success = true;
-      break;
+  if (channel->streamtype == kChannelStreamInternal) {
+    channel_incref(channel);
+    CREATE_EVENT(channel->events, internal_read_event, 2, channel, buffer);
+    success = true;
+  } else {
+    Stream *in = channel_instream(channel);
+    success = wstream_write(in, buffer);
  }

+
  if (!success) {
    // If the write failed for any reason, close the channel
    char buf[256];
@@ -609,14 +505,14 @@ static void internal_read_event(void **argv)
  Channel *channel = argv[0];
  WBuffer *buffer = argv[1];

-  msgpack_unpacker_reserve_buffer(channel->unpacker, buffer->size);
-  memcpy(msgpack_unpacker_buffer(channel->unpacker),
+  msgpack_unpacker_reserve_buffer(channel->rpc.unpacker, buffer->size);
+  memcpy(msgpack_unpacker_buffer(channel->rpc.unpacker),
         buffer->data, buffer->size);
-  msgpack_unpacker_buffer_consumed(channel->unpacker, buffer->size);
+  msgpack_unpacker_buffer_consumed(channel->rpc.unpacker, buffer->size);

  parse_msgpack(channel);

-  decref(channel);
+  channel_decref(channel);
  wstream_release_wbuffer(buffer);
 }

@@ -665,7 +561,8 @@ static void broadcast_event(const char *name, Array args)
  Channel *channel;

  map_foreach_value(channels, channel, {
-    if (pmap_has(cstr_t)(channel->subscribed_events, name)) {
+    if (channel->is_rpc
+        && pmap_has(cstr_t)(channel->rpc.subscribed_events, name)) {
      kv_push(subscribed, channel);
    }
  });
@@ -695,10 +592,11 @@ end:
 static void unsubscribe(Channel *channel, char *event)
 {
  char *event_string = pmap_get(cstr_t)(event_strings, event);
-  pmap_del(cstr_t)(channel->subscribed_events, event_string);
+  pmap_del(cstr_t)(channel->rpc.subscribed_events, event_string);

  map_foreach_value(channels, channel, {
-    if (pmap_has(cstr_t)(channel->subscribed_events, event_string)) {
+    if (channel->is_rpc
+        && pmap_has(cstr_t)(channel->rpc.subscribed_events, event_string)) {
      return;
    }
  });
@@ -709,86 +607,65 @@ static void unsubscribe(Channel *channel, char *event)
 }

 /// Close the channel streams/process and free the channel resources.
+/// TODO: move to channel.h
 static void close_channel(Channel *channel)
 {
-  if (channel->closed) {
+  if (channel->rpc.closed) {
    return;
  }

-  channel->closed = true;
+  channel->rpc.closed = true;

-  switch (channel->type) {
-    case kChannelTypeSocket:
-      stream_close(&channel->data.stream, NULL, NULL);
+  switch (channel->streamtype) {
+    case kChannelStreamSocket:
+      stream_close(&channel->stream.socket, NULL, NULL);
      break;
-    case kChannelTypeProc:
+    case kChannelStreamProc:
      // Only close the rpc channel part,
      // there could be an error message on the stderr stream
-      process_close_in(channel->data.proc);
-      process_close_out(channel->data.proc);
+      process_close_in(&channel->stream.proc);
+      process_close_out(&channel->stream.proc);
      break;
-    case kChannelTypeStdio:
-      stream_close(&channel->data.std.in, NULL, NULL);
-      stream_close(&channel->data.std.out, NULL, NULL);
+    case kChannelStreamStdio:
+      stream_close(&channel->stream.stdio.in, NULL, NULL);
+      stream_close(&channel->stream.stdio.out, NULL, NULL);
      multiqueue_put(main_loop.fast_events, exit_event, 1, channel);
      return;
-    case kChannelTypeInternal:
+    case kChannelStreamInternal:
      // nothing to free.
      break;
  }

-  decref(channel);
+  channel_decref(channel);
 }

 static void exit_event(void **argv)
 {
-  decref(argv[0]);
+  channel_decref(argv[0]);

  if (!exiting) {
    mch_exit(0);
  }
 }

-static void free_channel(Channel *channel)
+void rpc_free(Channel *channel)
 {
  remote_ui_disconnect(channel->id);
-  pmap_del(uint64_t)(channels, channel->id);
-  msgpack_unpacker_free(channel->unpacker);
+  msgpack_unpacker_free(channel->rpc.unpacker);

  // Unsubscribe from all events
  char *event_string;
-  map_foreach_value(channel->subscribed_events, event_string, {
+  map_foreach_value(channel->rpc.subscribed_events, event_string, {
    unsubscribe(channel, event_string);
  });

-  pmap_free(cstr_t)(channel->subscribed_events);
-  kv_destroy(channel->call_stack);
-  if (channel->type != kChannelTypeProc) {
-    multiqueue_free(channel->events);
-  }
-  xfree(channel);
+  pmap_free(cstr_t)(channel->rpc.subscribed_events);
+  kv_destroy(channel->rpc.call_stack);
 }

 static void close_cb(Stream *stream, void *data)
 {
-  decref(data);
-}
-
-static Channel *register_channel(ChannelType type, uint64_t id,
-                                 MultiQueue *events)
-{
-  Channel *rv = xmalloc(sizeof(Channel));
-  rv->events = events ? events : multiqueue_new_child(main_loop.events);
-  rv->type = type;
-  rv->refcount = 1;
-  rv->closed = false;
-  rv->unpacker = msgpack_unpacker_new(MSGPACK_UNPACKER_INIT_BUFFER_SIZE);
-  rv->id = id > 0 ? id : next_chan_id++;
-  rv->subscribed_events = pmap_new(cstr_t)();
-  rv->next_request_id = 1;
-  kv_init(rv->call_stack);
-  pmap_put(uint64_t)(channels, rv->id, rv);
-  return rv;
+  channel_decref(data);
 }

 static bool is_rpc_response(msgpack_object *obj)
@@ -803,15 +680,18 @@ static bool is_rpc_response(msgpack_object *obj)
 static bool is_valid_rpc_response(msgpack_object *obj, Channel *channel)
 {
  uint64_t response_id = obj->via.array.ptr[1].via.u64;
+  if (kv_size(channel->rpc.call_stack) == 0) {
+    return false;
+  }
+
  // Must be equal to the frame at the stack's bottom
-  return kv_size(channel->call_stack) && response_id
-    == kv_A(channel->call_stack, kv_size(channel->call_stack) - 1)->request_id;
+  ChannelCallFrame *frame = kv_last(channel->rpc.call_stack);
+  return response_id == frame->request_id;
 }

 static void complete_call(msgpack_object *obj, Channel *channel)
 {
-  ChannelCallFrame *frame = kv_A(channel->call_stack,
-                             kv_size(channel->call_stack) - 1);
+  ChannelCallFrame *frame = kv_last(channel->rpc.call_stack);
  frame->returned = true;
  frame->errored = obj->via.array.ptr[2].type != MSGPACK_OBJECT_NIL;

@@ -825,8 +705,8 @@ static void complete_call(msgpack_object *obj, Channel *channel)
 static void call_set_error(Channel *channel, char *msg, int loglevel)
 {
  LOG(loglevel, "RPC: %s", msg);
-  for (size_t i = 0; i < kv_size(channel->call_stack); i++) {
-    ChannelCallFrame *frame = kv_A(channel->call_stack, i);
+  for (size_t i = 0; i < kv_size(channel->rpc.call_stack); i++) {
+    ChannelCallFrame *frame = kv_A(channel->rpc.call_stack, i);
    frame->returned = true;
    frame->errored = true;
    api_free_object(frame->result);
@@ -875,18 +755,6 @@ static WBuffer *serialize_response(uint64_t channel_id,
  return rv;
 }

-static void incref(Channel *channel)
-{
-  channel->refcount++;
-}
-
-static void decref(Channel *channel)
-{
-  if (!(--channel->refcount)) {
-    free_channel(channel);
-  }
-}
-
 #if MIN_LOG_LEVEL <= DEBUG_LOG_LEVEL
 #define REQ "[request]  "
 #define RES "[response] "
--- a/src/nvim/msgpack_rpc/channel.h
+++ b/src/nvim/msgpack_rpc/channel.h
@@ -8,6 +8,7 @@
 #include "nvim/event/socket.h"
 #include "nvim/event/process.h"
 #include "nvim/vim.h"
+#include "nvim/channel.h"

 #define METHOD_MAXLEN 512

@@ -16,6 +17,7 @@
 ///       of os_inchar(), so they are processed "just-in-time".
 MultiQueue *ch_before_blocking_events;

+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "msgpack_rpc/channel.h.generated.h"
 #endif
--- a/src/nvim/msgpack_rpc/channel_defs.h
+++ b/src/nvim/msgpack_rpc/channel_defs.h
@@ -0,0 +1,36 @@
+#ifndef NVIM_MSGPACK_RPC_CHANNEL_DEFS_H
+#define NVIM_MSGPACK_RPC_CHANNEL_DEFS_H
+
+#include <stdbool.h>
+#include <uv.h>
+#include <msgpack.h>
+
+#include "nvim/api/private/defs.h"
+#include "nvim/event/socket.h"
+#include "nvim/event/process.h"
+#include "nvim/vim.h"
+
+typedef struct Channel Channel;
+
+typedef struct {
+  uint64_t request_id;
+  bool returned, errored;
+  Object result;
+} ChannelCallFrame;
+
+typedef struct {
+  Channel *channel;
+  MsgpackRpcRequestHandler handler;
+  Array args;
+  uint64_t request_id;
+} RequestEvent;
+
+typedef struct {
+  PMap(cstr_t) *subscribed_events;
+  bool closed;
+  msgpack_unpacker *unpacker;
+  uint64_t next_request_id;
+  kvec_t(ChannelCallFrame *) call_stack;
+} RpcState;
+
+#endif  // NVIM_MSGPACK_RPC_CHANNEL_DEFS_H