src: add abstract `IsolatePlatformDelegate`

Adds a new abstract class for module authors and embedders to register
arbitrary isolates with `node::MultiIsolatePlatform`.

PR-URL: https://github.com/nodejs/node/pull/30324
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/node.h b/src/node.h
index c80e6266857..f3da4574019 100644
--- a/src/node.h
+++ b/src/node.h
@@ -262,6 +262,12 @@ class NODE_EXTERN ArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
 NODE_EXTERN ArrayBufferAllocator* CreateArrayBufferAllocator();
 NODE_EXTERN void FreeArrayBufferAllocator(ArrayBufferAllocator* allocator);
 
+class NODE_EXTERN IsolatePlatformDelegate {
+ public:
+  virtual std::shared_ptr<v8::TaskRunner> GetForegroundTaskRunner() = 0;
+  virtual bool IdleTasksEnabled() = 0;
+};
+
 class NODE_EXTERN MultiIsolatePlatform : public v8::Platform {
  public:
   ~MultiIsolatePlatform() override = default;
@@ -283,6 +289,12 @@ class NODE_EXTERN MultiIsolatePlatform : public v8::Platform {
   // This function may only be called once per `Isolate`.
   virtual void RegisterIsolate(v8::Isolate* isolate,
                                struct uv_loop_s* loop) = 0;
+  // This method can be used when an application handles task scheduling on its
+  // own through `IsolatePlatformDelegate`. Upon registering an isolate with
+  // this overload any other method in this class with the exception of
+  // `UnregisterIsolate` *must not* be used on that isolate.
+  virtual void RegisterIsolate(v8::Isolate* isolate,
+                               IsolatePlatformDelegate* delegate) = 0;
 
   // This function may only be called once per `Isolate`, and discard any
   // pending delayed tasks scheduled for that isolate.