class Fiber::ExecutionContext::Isolated

• Fiber::ExecutionContext::Isolated
• Reference
• Object

Overview

Isolated execution context. Runs a single thread with a single fiber.

Concurrency is disabled within the thread: the fiber owns the thread and the thread can only run this fiber. Keep in mind that the fiber will still run in parallel to other fibers running in other execution contexts.

The fiber can still spawn fibers into other execution contexts. Since it can be inconvenient to pass an execution context around, calls to ::spawn will spawn a fiber into the specified spawn_context that defaults to the default execution context.

Isolated fibers can normally communicate with other fibers running in other execution contexts using Channel(T), WaitGroup or Mutex for example. They can also execute IO operations or sleep just like any other fiber.

Calls that result in waiting (e.g. sleep, or socket read/write) will block the thread since there are no other fibers to switch to. This in turn allows to call anything that would block the thread without blocking any other fiber.

You can for example use an isolated fiber to run a blocking GUI loop, transparently forward ::spawn to the default context, and eventually only block the current fiber while waiting for the GUI application to quit:

gtk = Fiber::ExecutionContext::Isolated.new("Gtk") do
  Gtk.main
end
gtk.wait

Included Modules

• Fiber::ExecutionContext
• Fiber::ExecutionContext::Scheduler

Defined in:

Constructors

• .new(name : String, spawn_context : ExecutionContext = ExecutionContext.default, &func : -> )

  Starts a new thread named name to execute func.

Instance Method Summary

• #inspect(io : IO) : Nil

  Appends a String representation of this object which includes its class name, its object address and the values of all instance variables.

• #name : String
• #running? : Bool
• #spawn(*, name : String | Nil = nil, &block : -> ) : Fiber

  Instantiates a fiber and enqueues it into the scheduler's local queue.

• #status : String

  Returns the current status of the scheduler.

• #to_s(io : IO) : Nil

  Appends a short String representation of this object which includes its class name and its object address.

• #wait : Nil

  Blocks the calling fiber until the isolated context fiber terminates.

Constructor Detail

Instance Method Detail

class Person
  def initialize(@name : String, @age : Int32)
  end
end

Person.new("John", 32).inspect # => #<Person:0x10fd31f20 @name="John", @age=32>

class Person
  def initialize(@name : String, @age : Int32)
  end
end

Person.new("John", 32).to_s # => #<Person:0x10a199f20>

ctx = Fiber::ExecutionContext::Isolated.new("test") do
  raise "fail"
end
ctx.wait # => re-raises "fail"