user background job for hover provider to avoid blocking request queu…

…e on large documents

apps/els_lsp/src/els_hover_provider.erl

@@ -5,16 +5,24 @@
 
 -behaviour(els_provider).
 
--export([ handle_request/2
+-export([ handle_info/2
+ , handle_request/2
  , is_enabled/0
+ , init/0
+ , cancel_request/2
  ]).
 
 -include("els_lsp.hrl").
+-include_lib("kernel/include/logger.hrl").
+
+-define(SERVER, ?MODULE).
 
 %%==============================================================================
 %% Types
 %%==============================================================================
--type state() :: any().
+-type state() :: #{in_progress => [progress_entry()]}.
+-type progress_entry() :: {uri(), job()}.
+-type job() :: pid().
 
 %%==============================================================================
 %% els_provider functions
@@ -23,24 +31,72 @@
 is_enabled() ->
  true.
 
+-spec init() -> state().
+init() ->
+ #{ in_progress => []}.
+
 -spec handle_request(any(), state()) -> {any(), state()}.
 handle_request({hover, Params}, State) ->
+ #{in_progress := InProgress} = State,
  #{ <<"position">> := #{ <<"line">> := Line
  , <<"character">> := Character
  }
  , <<"textDocument">> := #{<<"uri">> := Uri}
  } = Params,
+ ?LOG_DEBUG("Starting hover job ""[uri=~p, line=~p, character=~p]"
+ , [Uri, Line, Character]
+ ),
+ Job = run_hover_job(Uri, Line, Character),
+ {Job, State#{in_progress => [{Uri, Job}|InProgress]}}.
+
+
+-spec handle_info(any(), state()) -> state().
+handle_info({result, HoverResp, Job}, State) ->
+ ?LOG_DEBUG("Received hover result [job=~p]", [Job]),
+ #{ in_progress := InProgress } = State,
+ els_server:send_response(Job, HoverResp),
+ State#{ in_progress => lists:keydelete(Job, 2, InProgress) }.
+
+-spec cancel_request(job(), state()) -> state().
+cancel_request(Job, State) ->
+ ?LOG_DEBUG("Cancelling hover [job=~p]", [Job]),
+ els_background_job:stop(Job),
+ #{ in_progress := InProgress } = State,
+ State#{ in_progress => lists:keydelete(Job, 2, InProgress) }.
+
+
+%%==============================================================================
+%% Internal Functions
+%%==============================================================================
+
+-spec run_hover_job(uri(), line(), column()) -> pid().
+run_hover_job(Uri, Line, Character) ->
  {ok, Doc} = els_utils:lookup_document(Uri),
  POIs = els_dt_document:get_element_at_pos(Doc, Line + 1, Character + 1),
- {get_docs(Uri, POIs), State}.
+ Config = #{ task => fun get_docs/2
+ , entries => [{Uri, POIs}]
+ , title => <<"Hover">>
+ , on_complete =>
+ fun(HoverResp) ->
+ ?SERVER ! {result, HoverResp, self()},
+ ok
+ end
+ },
+ {ok, Pid} = els_background_job:new(Config),
+ Pid.
+
+-spec get_docs({uri(), [poi()]}, undefined) -> map() | null.
+get_docs({Uri, POIs}, _) ->
+ do_get_docs(Uri, POIs).
+
 
--spec get_docs(uri(), [poi()]) -> map() | null.
-get_docs(_Uri, []) ->
+-spec do_get_docs(uri(), [poi()]) -> map() | null.
+do_get_docs(_Uri, []) ->
  null;
-get_docs(Uri, [POI|Rest]) ->
+do_get_docs(Uri, [POI|Rest]) ->
  case els_docs:docs(Uri, POI) of
  [] ->
- get_docs(Uri, Rest);
+ do_get_docs(Uri, Rest);
  Entries ->
  #{contents => els_markup_content:new(Entries)}
  end.

apps/els_lsp/src/els_methods.erl

@@ -231,8 +231,8 @@ textdocument_documentsymbol(Params, State) ->
 -spec textdocument_hover(params(), state()) -> result().
 textdocument_hover(Params, State) ->
  Provider = els_hover_provider,
- Response = els_provider:handle_request(Provider, {hover, Params}),
- {response, Response, State}.
+ Job = els_provider:handle_request(Provider, {hover, Params}),
+ {noresponse, {Provider, Job}, State}.
 
 %%==============================================================================
 %% textDocument/completion