fix

Author: peihan.cph

shell/common/shell.cc

@@ -52,8 +52,7 @@ Shell::CreateShellOnPlatformThread(
   auto shell_holder_future = shell_holder_promise.get_future();
   if (!task_runners.IsValid()) {
     FML_LOG(ERROR) << "Task runners to run the shell were invalid.";
-    std::unique_ptr<Shell::ShellHolder> empty;
-    shell_holder_promise.set_value(std::move(empty));
+    shell_holder_promise.set_value(std::move(nullptr));
     return shell_holder_future;
   }
 
@@ -69,8 +68,8 @@ Shell::CreateShellOnPlatformThread(
   fml::TaskRunner::RunNowOrPostTask(
       task_runners.GetRasterTaskRunner(),
       [rasterizer_promise, snapshot_delegate_promise,
-       on_create_rasterizer = std::move(on_create_rasterizer),  //
-       shell = shell.get()                                      //
+       on_create_rasterizer,  //
+       shell = shell.get()    //
   ]() mutable {
         TRACE_EVENT0("flutter", "ShellSetupGPUSubsystem");
         std::unique_ptr<Rasterizer> rasterizer(on_create_rasterizer(*shell));
@@ -81,17 +80,15 @@ Shell::CreateShellOnPlatformThread(
   // Create the platform view on the platform thread (this thread).
   auto platform_view = on_create_platform_view(*shell.get());
   if (!platform_view || !platform_view->GetWeakPtr()) {
-    std::unique_ptr<Shell::ShellHolder> empty;
-    shell_holder_promise.set_value(std::move(empty));
+    shell_holder_promise.set_value(std::move(nullptr));
     return shell_holder_future;
   }
 
   // Ask the platform view for the vsync waiter. This will be used by the engine
   // to create the animator.
   auto vsync_waiter = platform_view->CreateVSyncWaiter();
   if (!vsync_waiter) {
-    std::unique_ptr<Shell::ShellHolder> empty;
-    shell_holder_promise.set_value(std::move(empty));
+    shell_holder_promise.set_value(std::move(nullptr));
     return shell_holder_future;
   }
 
@@ -113,9 +110,7 @@ Shell::CreateShellOnPlatformThread(
   // https://github.com/flutter/flutter/issues/42948
   fml::TaskRunner::RunNowOrPostTask(
       io_task_runner,
-      [io_task_runner,
-       io_manager_promise,  //
-       weak_io_manager_promise,
+      [io_task_runner, io_manager_promise, weak_io_manager_promise,
        weak_platform_view = platform_view->GetWeakPtr(),                  //
        is_backgrounded_sync_switch = shell->GetIsGpuDisabledSyncSwitch()  //
   ]() mutable {
@@ -332,8 +327,7 @@ std::future<std::unique_ptr<Shell::ShellHolder>> Shell::initShellEnv(
   if (!task_runners.IsValid() || !on_create_platform_view ||
       !on_create_rasterizer) {
     std::promise<std::unique_ptr<Shell::ShellHolder>> shell_holder_promise;
-    std::unique_ptr<Shell::ShellHolder> empty;
-    shell_holder_promise.set_value(std::move(empty));
+    shell_holder_promise.set_value(nullptr);
     return shell_holder_promise.get_future();
   }
 
@@ -1562,22 +1556,21 @@ std::unique_ptr<Shell> Shell::ShellHolder::makeShell() {
     return nullptr;
   }
   is_consumed_ = true;
-  fml::AutoResetWaitableEvent latch;
-  std::unique_ptr<Shell> shell_res;
+  std::promise<bool> init_promise;
 
   // make sure `shell.setup` executed on platformthread
   fml::TaskRunner::RunNowOrPostTask(
       shell_->GetTaskRunners().GetPlatformTaskRunner(),
-      fml::MakeCopyable([this, &latch, &shell_res]() mutable {
+      fml::MakeCopyable([this, &init_promise]() mutable {
         if (this->shell_->Setup(
                 std::move(this->platform_view_), std::move(this->engine_),
                 std::move(this->rasterizer_), std::move(this->io_manager_))) {
-          shell_res = std::move(this->shell_);
+          init_promise.set_value(true);
         }
-        latch.Signal();
+         init_promise.set_value(false);
       }));
-  latch.Wait();
-  return shell_res;
+
+    return std::move(shell_);
 }
 
 }  // namespace flutter