类 Ractor

返回当前正在运行或阻塞（等待）的 Ractor 数量。

Ractor.count                   #=> 1
r = Ractor.new(name: 'example') { Ractor.yield(1) }
Ractor.count                   #=> 2 (main + example ractor)
r.take                         # wait for Ractor.yield(1)
r.take                         # wait until r will finish
Ractor.count                   #=> 1

# File ractor.rb, line 302
def self.count
  __builtin_cexpr! %q{
    ULONG2NUM(GET_VM()->ractor.cnt);
  }
end

返回当前正在执行的 Ractor。

Ractor.current #=> #<Ractor:#1 running>

# File ractor.rb, line 288
def self.current
  __builtin_cexpr! %q{
    rb_ractor_self(rb_ec_ractor_ptr(ec));
  }
end

返回主 Ractor

# File ractor.rb, line 848
def self.main
  __builtin_cexpr! %q{
    rb_ractor_self(GET_VM()->ractor.main_ractor);
  }
end

使 obj 在 Ractor 之间可共享。

obj 及其引用的所有对象都将被冻结，除非它们已经是可共享的。

如果 copy 关键字为 true，它将在冻结对象之前复制它们，并且不会修改 obj 或其内部对象。

请注意，此方法的规范和实现尚未成熟，将来可能会更改。

obj = ['test']
Ractor.shareable?(obj)     #=> false
Ractor.make_shareable(obj) #=> ["test"]
Ractor.shareable?(obj)     #=> true
obj.frozen?                #=> true
obj[0].frozen?             #=> true

# Copy vs non-copy versions:
obj1 = ['test']
obj1s = Ractor.make_shareable(obj1)
obj1.frozen?                        #=> true
obj1s.object_id == obj1.object_id   #=> true
obj2 = ['test']
obj2s = Ractor.make_shareable(obj2, copy: true)
obj2.frozen?                        #=> false
obj2s.frozen?                       #=> true
obj2s.object_id == obj2.object_id   #=> false
obj2s[0].object_id == obj2[0].object_id #=> false

另请参阅 Ractor 类文档中的“可共享和不可共享对象”部分。

# File ractor.rb, line 825
def self.make_shareable obj, copy: false
  if copy
    __builtin_cexpr! %q{
      rb_ractor_make_shareable_copy(obj);
    }
  else
    __builtin_cexpr! %q{
      rb_ractor_make_shareable(obj);
    }
  end
end

使用参数和块创建一个新的 Ractor。

给定的块 (Proc) 将被隔离（无法访问任何外部变量）。块内部的 self 将引用当前 Ractor。

r = Ractor.new { puts "Hi, I am #{self.inspect}" }
r.take
# Prints "Hi, I am #<Ractor:#2 test.rb:1 running>"

传递的任何 args 都将通过与通过 send/Ractor.receive 发送的对象相同的规则传播到块参数。如果 args 中的参数不可共享，它将被复制（通过深度克隆，这可能效率低下）。

arg = [1, 2, 3]
puts "Passing: #{arg} (##{arg.object_id})"
r = Ractor.new(arg) {|received_arg|
  puts "Received: #{received_arg} (##{received_arg.object_id})"
}
r.take
# Prints:
#   Passing: [1, 2, 3] (#280)
#   Received: [1, 2, 3] (#300)

Ractor 的 name 可以设置为调试目的

r = Ractor.new(name: 'my ractor') {}; r.take
p r
#=> #<Ractor:#3 my ractor test.rb:1 terminated>

# File ractor.rb, line 273
def self.new(*args, name: nil, &block)
  b = block # TODO: builtin bug
  raise ArgumentError, "must be called with a block" unless block
  if __builtin_cexpr!("RBOOL(ruby_single_main_ractor)")
    warn("Ractor is experimental, and the behavior may change in future versions of Ruby! " \
         "Also there are many implementation issues.", uplevel: 0, category: :experimental)
  end
  loc = caller_locations(1, 1).first
  loc = "#{loc.path}:#{loc.lineno}"
  __builtin_ractor_create(loc, name, args, b)
end

从当前 Ractor 的传入端口接收消息（该消息是由另一个 Ractor 通过 send 发送到那里的）。

r = Ractor.new do
  v1 = Ractor.receive
  puts "Received: #{v1}"
end
r.send('message1')
r.take
# Here will be printed: "Received: message1"

或者，可以使用私有实例方法 receive

r = Ractor.new do
  v1 = receive
  puts "Received: #{v1}"
end
r.send('message1')
r.take
# This prints: "Received: message1"

如果队列为空，则方法会阻塞。

r = Ractor.new do
  puts "Before first receive"
  v1 = Ractor.receive
  puts "Received: #{v1}"
  v2 = Ractor.receive
  puts "Received: #{v2}"
end
wait
puts "Still not received"
r.send('message1')
wait
puts "Still received only one"
r.send('message2')
r.take

输出

Before first receive
Still not received
Received: message1
Still received only one
Received: message2

如果在 ractor 上调用了 close_incoming，则如果传入队列中没有更多消息，该方法会引发 Ractor::ClosedError

Ractor.new do
  close_incoming
  receive
end
wait
# in `receive': The incoming port is already closed => #<Ractor:#2 test.rb:1 running> (Ractor::ClosedError)

# File ractor.rb, line 430
def self.receive
  __builtin_cexpr! %q{
    ractor_receive(ec, rb_ec_ractor_ptr(ec))
  }
end

仅接收特定消息。

与 Ractor.receive 不同，Ractor.receive_if 可以使用块中的模式（或任何过滤器）来选择 ractor 的传入队列中可用的消息。

r = Ractor.new do
  p Ractor.receive_if{|msg| msg.match?(/foo/)} #=> "foo3"
  p Ractor.receive_if{|msg| msg.match?(/bar/)} #=> "bar1"
  p Ractor.receive_if{|msg| msg.match?(/baz/)} #=> "baz2"
end
r << "bar1"
r << "baz2"
r << "foo3"
r.take

这将输出

foo3
bar1
baz2

如果块返回真值，则消息将从传入队列中删除并返回。否则，消息将保留在传入队列中，并且给定块将检查下一条消息。

如果传入队列中没有剩余消息，则该方法将阻塞，直到有新消息到达。

如果块通过 break/return/exception/throw 退出，则消息将从传入队列中删除，就像返回了真值一样。

r = Ractor.new do
  val = Ractor.receive_if{|msg| msg.is_a?(Array)}
  puts "Received successfully: #{val}"
end

r.send(1)
r.send('test')
wait
puts "2 non-matching sent, nothing received"
r.send([1, 2, 3])
wait

打印

2 non-matching sent, nothing received
Received successfully: [1, 2, 3]

请注意，您不能在给定块中递归调用 receive/receive_if。您不应该在块中执行除消息过滤之外的任何任务。

Ractor.current << true
Ractor.receive_if{|msg| Ractor.receive}
#=> `receive': can not call receive/receive_if recursively (Ractor::Error)

# File ractor.rb, line 509
def self.receive_if &b
  Primitive.ractor_receive_if b
end

等待任何 ractor 在其输出端口中拥有内容，从该 ractor 读取，然后返回该 ractor 和接收到的对象。

r1 = Ractor.new {Ractor.yield 'from 1'}
r2 = Ractor.new {Ractor.yield 'from 2'}

r, obj = Ractor.select(r1, r2)

puts "received #{obj.inspect} from #{r.inspect}"
# Prints: received "from 1" from #<Ractor:#2 test.rb:1 running>
# But could just as well print "from r2" here, either prints could be first.

如果给定的 ractor 之一是当前 ractor，并且它被选中，则 r 将包含 :receive 符号而不是 ractor 对象。

r1 = Ractor.new(Ractor.current) do |main|
  main.send 'to main'
  Ractor.yield 'from 1'
end
r2 = Ractor.new do
  Ractor.yield 'from 2'
end

r, obj = Ractor.select(r1, r2, Ractor.current)
puts "received #{obj.inspect} from #{r.inspect}"
# Could print: received "to main" from :receive

如果提供了 yield_value，则如果另一个 ractor 正在调用 take，则可以生成该值。在这种情况下，将返回对 [:yield, nil]。

r1 = Ractor.new(Ractor.current) do |main|
  puts "Received from main: #{main.take}"
end

puts "Trying to select"
r, obj = Ractor.select(r1, Ractor.current, yield_value: 123)
wait
puts "Received #{obj.inspect} from #{r.inspect}"

这将打印

Trying to select
Received from main: 123
Received nil from :yield

move 布尔标志定义是否复制（默认）或移动生成的值。

# File ractor.rb, line 358
def self.select(*ractors, yield_value: yield_unspecified = true, move: false)
  raise ArgumentError, 'specify at least one ractor or `yield_value`' if yield_unspecified && ractors.empty?

  if ractors.delete Ractor.current
    do_receive = true
  else
    do_receive = false
  end

  __builtin_ractor_select_internal ractors, do_receive, !yield_unspecified, yield_value, move
end

检查对象是否可以被 ractor 共享。

Ractor.shareable?(1)            #=> true -- numbers and other immutable basic values are frozen
Ractor.shareable?('foo')        #=> false, unless the string is frozen due to # frozen_string_literal: true
Ractor.shareable?('foo'.freeze) #=> true

另请参阅 Ractor 类文档中的“可共享和不可共享对象”部分。

# File ractor.rb, line 784
def self.shareable? obj
  __builtin_cexpr! %q{
    RBOOL(rb_ractor_shareable_p(obj));
  }
end

将消息发送到当前 Ractor 的输出端口，以便被 take 接收。

r = Ractor.new {Ractor.yield 'Hello from ractor'}
puts r.take
# Prints: "Hello from ractor"

此方法是阻塞的，只有在有人消费发送的消息时才会返回。

r = Ractor.new do
  Ractor.yield 'Hello from ractor'
  puts "Ractor: after yield"
end
wait
puts "Still not taken"
puts r.take

这将打印

Still not taken
Hello from ractor
Ractor: after yield

如果输出端口已使用 close_outgoing 关闭，则该方法将引发

r = Ractor.new do
  close_outgoing
  Ractor.yield 'Hello from ractor'
end
wait
# `yield': The outgoing-port is already closed (Ractor::ClosedError)

move 参数的含义与 send 相同。

# File ractor.rb, line 643
def self.yield(obj, move: false)
  __builtin_cexpr! %q{
    ractor_yield(ec, rb_ec_ractor_ptr(ec), obj, move)
  }
end

从 Ractor 本地存储中获取值

# File ractor.rb, line 838
def [](sym)
  Primitive.ractor_local_value(sym)
end

在 Ractor 本地存储中设置值

# File ractor.rb, line 843
def []=(sym, val)
  Primitive.ractor_local_value_set(sym, val)
end

关闭输入端口并返回它是否已关闭。所有进一步尝试在 Ractor 中 Ractor.receive，以及向 Ractor 发送 send 将失败，并出现 Ractor::ClosedError 错误。

r = Ractor.new {sleep(500)}
r.close_incoming  #=> false
r.close_incoming  #=> true
r.send('test')
# Ractor::ClosedError (The incoming-port is already closed)

# File ractor.rb, line 749
def close_incoming
  __builtin_cexpr! %q{
    ractor_close_incoming(ec, RACTOR_PTR(self));
  }
end

关闭输出端口并返回它是否已关闭。所有进一步尝试在 Ractor 中 Ractor.yield，以及从 Ractor 中 take 将失败，并出现 Ractor::ClosedError 错误。

r = Ractor.new {sleep(500)}
r.close_outgoing  #=> false
r.close_outgoing  #=> true
r.take
# Ractor::ClosedError (The outgoing-port is already closed)

# File ractor.rb, line 767
def close_outgoing
  __builtin_cexpr! %q{
    ractor_close_outgoing(ec, RACTOR_PTR(self));
  }
end

在 Ractor.new 中设置的名称，或 nil。

# File ractor.rb, line 729
def name
  __builtin_cexpr! %q{RACTOR_PTR(self)->name}
end

将消息发送到 Ractor 的输入队列，以便被 Ractor.receive 接收。

r = Ractor.new do
  value = Ractor.receive
  puts "Received #{value}"
end
r.send 'message'
# Prints: "Received: message"

该方法是非阻塞的（即使 Ractor 尚未准备好接收任何内容，也会立即返回）。

r = Ractor.new {sleep(5)}
r.send('test')
puts "Sent successfully"
# Prints: "Sent successfully" immediately

尝试向已完成执行的 Ractor 发送消息将引发 Ractor::ClosedError 错误。

r = Ractor.new {}
r.take
p r
# "#<Ractor:#6 (irb):23 terminated>"
r.send('test')
# Ractor::ClosedError (The incoming-port is already closed)

如果在该 ractor 上调用了 close_incoming，该方法也会引发 Ractor::ClosedError。

r =  Ractor.new do
  sleep(500)
  receive
end
r.close_incoming
r.send('test')
# Ractor::ClosedError (The incoming-port is already closed)
# The error is raised immediately, not when the ractor tries to receive

如果 obj 不可共享，默认情况下它将通过深度克隆复制到接收 ractor 中。如果传递了 move: true，则该对象将被移动到接收 ractor 中，并且发送方将无法访问它。

r = Ractor.new {puts "Received: #{receive}"}
msg = 'message'
r.send(msg, move: true)
r.take
p msg

这将打印

Received: message
in `p': undefined method `inspect' for #<Ractor::MovedObject:0x000055c99b9b69b8>

发送方对该对象及其所有部分的引用将变得无效。

r = Ractor.new {puts "Received: #{receive}"}
s = 'message'
ary = [s]
copy = ary.dup
r.send(ary, move: true)

s.inspect
# Ractor::MovedError (can not send any methods to a moved object)
ary.class
# Ractor::MovedError (can not send any methods to a moved object)
copy.class
# => Array, it is different object
copy[0].inspect
# Ractor::MovedError (can not send any methods to a moved object)
# ...but its item was still a reference to `s`, which was moved

如果该对象是可共享的，move: true 对它没有影响。

r = Ractor.new {puts "Received: #{receive}"}
s = 'message'.freeze
r.send(s, move: true)
s.inspect #=> "message", still available

# File ractor.rb, line 599
def send(obj, move: false)
  __builtin_cexpr! %q{
    ractor_send(ec, RACTOR_PTR(self), obj, move)
  }
end

从 ractor 的输出端口获取一条消息，该消息由 Ractor.yield 或在 ractor 终止时放入。

r = Ractor.new do
  Ractor.yield 'explicit yield'
  'last value'
end
puts r.take #=> 'explicit yield'
puts r.take #=> 'last value'
puts r.take # Ractor::ClosedError (The outgoing-port is already closed)

最后一个值也被发送到输出端口这一事实意味着 take 可以用作 Thread#join 的模拟（“只需等待 ractor 完成”）。但是，如果有人已经消费了该消息，它将引发异常。

如果输出端口使用 close_outgoing 关闭，该方法将引发 Ractor::ClosedError。

r = Ractor.new do
  sleep(500)
  Ractor.yield 'Hello from ractor'
end
r.close_outgoing
r.take
# Ractor::ClosedError (The outgoing-port is already closed)
# The error would be raised immediately, not when ractor will try to receive

如果在 Ractor 中引发了未捕获的异常，它将通过 take 作为 Ractor::RemoteError 传播。

r = Ractor.new {raise "Something weird happened"}

begin
  r.take
rescue => e
  p e              #  => #<Ractor::RemoteError: thrown by remote Ractor.>
  p e.ractor == r  # => true
  p e.cause        # => #<RuntimeError: Something weird happened>
end

Ractor::ClosedError 是 StopIteration 的后代，因此 ractor 的终止将使任何接收此消息的循环退出，而不会传播错误。

r = Ractor.new do
  3.times {|i| Ractor.yield "message #{i}"}
  "finishing"
end

loop {puts "Received: " + r.take}
puts "Continue successfully"

这将打印

Received: message 0
Received: message 1
Received: message 2
Received: finishing
Continue successfully

# File ractor.rb, line 710
def take
  __builtin_cexpr! %q{
    ractor_take(ec, RACTOR_PTR(self))
  }
end

与 Ractor.receive 相同

# File ractor.rb, line 441
        def receive
  __builtin_cexpr! %q{
    ractor_receive(ec, rb_ec_ractor_ptr(ec))
  }
end

与 Ractor.receive_if 相同

# File ractor.rb, line 514
        def receive_if &b
  Primitive.ractor_receive_if b
end