Revert "fixes #133: same task runner for platform&render" (#421)

Author: pchampio

application.go

@@ -260,8 +260,6 @@ func (a *Application) Run() error {
 			fmt.Printf("go-flutter: engine.Run() returned result code %d (invalid library version)\n", result)
 		case embedder.ResultInvalidArguments:
 			fmt.Printf("go-flutter: engine.Run() returned result code %d (invalid arguments)\n", result)
-		case embedder.ResultInternalInconsistency:
-			fmt.Printf("go-flutter: engine.Run() returned result code %d (internal inconsistency)\n", result)
 		default:
 			fmt.Printf("go-flutter: engine.Run() returned result code %d (unknown result code)\n", result)
 		}

embedder/embedder.go

@@ -30,7 +30,6 @@ const (
 	ResultSuccess               Result = C.kSuccess
 	ResultInvalidLibraryVersion Result = C.kInvalidLibraryVersion
 	ResultInvalidArguments      Result = C.kInvalidArguments
-	ResultInternalInconsistency Result = C.kInternalInconsistency
 	ResultEngineNotRunning      Result = -1
 )
 

embedder/embedder_helper.c

@@ -51,9 +51,7 @@ FlutterEngineResult runFlutter(void *user_data, FlutterEngine *engine, FlutterPr
 
   FlutterCustomTaskRunners custom_task_runners = {};
   custom_task_runners.struct_size = sizeof(FlutterCustomTaskRunners);
-  // Render task and platform task are handled by the same TaskRunner
   custom_task_runners.platform_task_runner = &platform_task_runner;
-  custom_task_runners.render_task_runner = &platform_task_runner;
   Args->custom_task_runners = &custom_task_runners;
 
   return FlutterEngineRun(FLUTTER_ENGINE_VERSION, &config, Args, user_data,

event-loop.go

@@ -7,12 +7,11 @@ import (
 	"time"
 
 	"github.com/go-flutter-desktop/go-flutter/embedder"
-	"github.com/go-flutter-desktop/go-flutter/internal/currentthread"
 	"github.com/go-flutter-desktop/go-flutter/internal/priorityqueue"
 )
 
 // EventLoop is a event loop for the main thread that allows for delayed task
-// execution.
+// execution.()
 type EventLoop struct {
 	// store the task (event) by their priorities
 	priorityqueue *priorityqueue.PriorityQueue
@@ -23,19 +22,17 @@ type EventLoop struct {
 
 	// timeout for non-Rendering events that needs to be processed in a polling manner
 	platformMessageRefreshRate time.Duration
-
-	// identifier for the current thread
-	mainThreadID int64
 }
 
+// newEventLoop must ALWAYS be called if the calling goroutine is
+// `runtime.LockOSThread()`
 func newEventLoop(postEmptyEvent func(), onExpiredTask func(*embedder.FlutterTask) embedder.Result) *EventLoop {
 	pq := priorityqueue.NewPriorityQueue()
 	heap.Init(pq)
 	return &EventLoop{
 		priorityqueue:  pq,
 		postEmptyEvent: postEmptyEvent,
 		onExpiredTask:  onExpiredTask,
-		mainThreadID:   currentthread.ID(),
 
 		// 25 Millisecond is arbitrary value, not too high (adds too much delay to
 		// platform messages) and not too low (heavy CPU consumption).
@@ -49,10 +46,17 @@ func newEventLoop(postEmptyEvent func(), onExpiredTask func(*embedder.FlutterTas
 	}
 }
 
-// RunOnCurrentThread return true if tasks posted on the
-// calling thread will be run on that same thread.
+// RunOnCurrentThread FlutterDocs:
+//   May be called from any thread. Should return true if tasks posted on the
+//   calling thread will be run on that same thread.
+//
+// The functions PostTask and onExpiredTask should be called from the same
+// thread, this is ensured if the creation of the event loop (through
+// `newEventLoop`) and the PostTask callback (through
+// `a.engine.TaskRunnerPostTask = eventLoop.PostTask`) are done on a calling
+// goroutine which always execute in that thread (`runtime.LockOSThread()`).
 func (t *EventLoop) RunOnCurrentThread() bool {
-	return currentthread.ID() == t.mainThreadID
+	return true
 }
 
 // PostTask posts a Flutter engine tasks to the event loop for delayed execution.