worker: implement `MessagePort` and `MessageChannel`

Implement `MessagePort` and `MessageChannel` along the lines of
the DOM classes of the same names. `MessagePort`s initially
support transferring only `ArrayBuffer`s.

Thanks to Stephen Belanger for reviewing this change in its
original form, to Benjamin Gruenbaum for reviewing the
added tests in their original form, and to Olivia Hugger
for reviewing the documentation in its original form.

Refs: https://github.com/ayojs/ayo/pull/98

PR-URL: https://github.com/nodejs/node/pull/20876
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Shingo Inoue <leko.noor@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: John-David Dalton <john.david.dalton@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/util.h b/src/util.h
index e272286d3e4..fade27458f3 100644
--- a/src/util.h
+++ b/src/util.h
@@ -436,8 +436,11 @@ struct MallocedBuffer {
     return ret;
   }
 
+  inline bool is_empty() const { return data == nullptr; }
+
   MallocedBuffer() : data(nullptr) {}
   explicit MallocedBuffer(size_t size) : data(Malloc<T>(size)), size(size) {}
+  MallocedBuffer(char* data, size_t size) : data(data), size(size) {}
   MallocedBuffer(MallocedBuffer&& other) : data(other.data), size(other.size) {
     other.data = nullptr;
   }