From ef2bb61018cd9ccb5b61a3d91911e04a773da4a7 Mon Sep 17 00:00:00 2001
From: Koichi Sasada <ko1@atdot.net>
Date: Tue, 27 May 2025 03:58:04 +0900
Subject: `Ractor::Port`

* Added `Ractor::Port`
  * `Ractor::Port#receive` (support multi-threads)
  * `Rcator::Port#close`
  * `Ractor::Port#closed?`
* Added some methods
  * `Ractor#join`
  * `Ractor#value`
  * `Ractor#monitor`
  * `Ractor#unmonitor`
* Removed some methods
  * `Ractor#take`
  * `Ractor.yield`
* Change the spec
  * `Racotr.select`

You can wait for multiple sequences of messages with `Ractor::Port`.

```ruby
ports = 3.times.map{ Ractor::Port.new }
ports.map.with_index do |port, ri|
  Ractor.new port,ri do |port, ri|
    3.times{|i| port << "r#{ri}-#{i}"}
  end
end

p ports.each{|port| pp 3.times.map{port.receive}}

```

In this example, we use 3 ports, and 3 Ractors send messages to them respectively.
We can receive a series of messages from each port.

You can use `Ractor#value` to get the last value of a Ractor's block:

```ruby
result = Ractor.new do
  heavy_task()
end.value
```

You can wait for the termination of a Ractor with `Ractor#join` like this:

```ruby
Ractor.new do
  some_task()
end.join
```

`#value` and `#join` are similar to `Thread#value` and `Thread#join`.

To implement `#join`, `Ractor#monitor` (and `Ractor#unmonitor`) is introduced.

This commit changes `Ractor.select()` method.
It now only accepts ports or Ractors, and returns when a port receives a message or a Ractor terminates.

We removes `Ractor.yield` and `Ractor#take` because:
* `Ractor::Port` supports most of similar use cases in a simpler manner.
* Removing them significantly simplifies the code.

We also change the internal thread scheduler code (thread_pthread.c):
* During barrier synchronization, we keep the `ractor_sched` lock to avoid deadlocks.
  This lock is released by `rb_ractor_sched_barrier_end()`
  which is called at the end of operations that require the barrier.
* fix potential deadlock issues by checking interrupts just before setting UBF.

https://bugs.ruby-lang.org/issues/21262
---
 common.mk | 1 +
 1 file changed, 1 insertion(+)

(limited to 'common.mk')

diff --git a/common.mk b/common.mk
index 7719047fd7..ad5ebac281 100644
--- a/common.mk
+++ b/common.mk
@@ -14293,6 +14293,7 @@ ractor.$(OBJEXT): {$(VPATH)}ractor.c
 ractor.$(OBJEXT): {$(VPATH)}ractor.h
 ractor.$(OBJEXT): {$(VPATH)}ractor.rbinc
 ractor.$(OBJEXT): {$(VPATH)}ractor_core.h
+ractor.$(OBJEXT): {$(VPATH)}ractor_sync.c
 ractor.$(OBJEXT): {$(VPATH)}ruby_assert.h
 ractor.$(OBJEXT): {$(VPATH)}ruby_atomic.h
 ractor.$(OBJEXT): {$(VPATH)}rubyparser.h
-- 
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