Results for: "Array"

Changes asynchronous interrupt timing.

interrupt means asynchronous event and corresponding procedure by Thread#raise, Thread#kill, signal trap (not supported yet) and main thread termination (if main thread terminates, then all other thread will be killed).

The given hash has pairs like ExceptionClass => :TimingSymbol. Where the ExceptionClass is the interrupt handled by the given block. The TimingSymbol can be one of the following symbols:

:immediate

Invoke interrupts immediately.

:on_blocking

Invoke interrupts while BlockingOperation.

:never

Never invoke all interrupts.

BlockingOperation means that the operation will block the calling thread, such as read and write. On CRuby implementation, BlockingOperation is any operation executed without GVL.

Masked asynchronous interrupts are delayed until they are enabled. This method is similar to sigprocmask(3).

NOTE

Asynchronous interrupts are difficult to use.

If you need to communicate between threads, please consider to use another way such as Queue.

Or use them with deep understanding about this method.

Usage

In this example, we can guard from Thread#raise exceptions.

Using the :never TimingSymbol the RuntimeError exception will always be ignored in the first block of the main thread. In the second ::handle_interrupt block we can purposefully handle RuntimeError exceptions.

th = Thread.new do
  Thread.handle_interrupt(RuntimeError => :never) {
    begin
      # You can write resource allocation code safely.
      Thread.handle_interrupt(RuntimeError => :immediate) {
        # ...
      }
    ensure
      # You can write resource deallocation code safely.
    end
  }
end
Thread.pass
# ...
th.raise "stop"

While we are ignoring the RuntimeError exception, it’s safe to write our resource allocation code. Then, the ensure block is where we can safely deallocate your resources.

Guarding from Timeout::Error

In the next example, we will guard from the Timeout::Error exception. This will help prevent from leaking resources when Timeout::Error exceptions occur during normal ensure clause. For this example we use the help of the standard library Timeout, from lib/timeout.rb

require 'timeout'
Thread.handle_interrupt(Timeout::Error => :never) {
  timeout(10){
    # Timeout::Error doesn't occur here
    Thread.handle_interrupt(Timeout::Error => :on_blocking) {
      # possible to be killed by Timeout::Error
      # while blocking operation
    }
    # Timeout::Error doesn't occur here
  }
}

In the first part of the timeout block, we can rely on Timeout::Error being ignored. Then in the Timeout::Error => :on_blocking block, any operation that will block the calling thread is susceptible to a Timeout::Error exception being raised.

Stack control settings

It’s possible to stack multiple levels of ::handle_interrupt blocks in order to control more than one ExceptionClass and TimingSymbol at a time.

Thread.handle_interrupt(FooError => :never) {
  Thread.handle_interrupt(BarError => :never) {
     # FooError and BarError are prohibited.
  }
}

Inheritance with ExceptionClass

All exceptions inherited from the ExceptionClass parameter will be considered.

Thread.handle_interrupt(Exception => :never) {
  # all exceptions inherited from Exception are prohibited.
}

Returns whether or not the asynchronous queue is empty.

Since Thread::handle_interrupt can be used to defer asynchronous events, this method can be used to determine if there are any deferred events.

If you find this method returns true, then you may finish :never blocks.

For example, the following method processes deferred asynchronous events immediately.

def Thread.kick_interrupt_immediately
  Thread.handle_interrupt(Object => :immediate) {
    Thread.pass
  }
end

If error is given, then check only for error type deferred events.

Usage

th = Thread.new{
  Thread.handle_interrupt(RuntimeError => :on_blocking){
    while true
      ...
      # reach safe point to invoke interrupt
      if Thread.pending_interrupt?
        Thread.handle_interrupt(Object => :immediate){}
      end
      ...
    end
  }
}
...
th.raise # stop thread

This example can also be written as the following, which you should use to avoid asynchronous interrupts.

flag = true
th = Thread.new{
  Thread.handle_interrupt(RuntimeError => :on_blocking){
    while true
      ...
      # reach safe point to invoke interrupt
      break if flag == false
      ...
    end
  }
}
...
flag = false # stop thread

Returns whether or not the asynchronous queue is empty for the target thread.

If error is given, then check only for error type deferred events.

See ::pending_interrupt? for more information.

Returns an array of the names of the thread-local variables (as Symbols).

thr = Thread.new do
  Thread.current.thread_variable_set(:cat, 'meow')
  Thread.current.thread_variable_set("dog", 'woof')
end
thr.join               #=> #<Thread:0x401b3f10 dead>
thr.thread_variables   #=> [:dog, :cat]

Note that these are not fiber local variables. Please see Thread#[] and Thread#thread_variable_get for more details.

Returns true if the given string (or symbol) exists as a thread-local variable.

me = Thread.current
me.thread_variable_set(:oliver, "a")
me.thread_variable?(:oliver)    #=> true
me.thread_variable?(:stanley)   #=> false

Note that these are not fiber local variables. Please see Thread#[] and Thread#thread_variable_get for more details.

Returns the execution stack for the target thread—an array containing backtrace location objects.

See Thread::Backtrace::Location for more information.

This method behaves similarly to Kernel#caller_locations except it applies to a specific thread.

Returns a raw seed string, using platform providing features.

Random.raw_seed(8)  #=> "\x78\x41\xBA\xAF\x7D\xEA\xD8\xEA"

Value from exception raised on the :raise event

Returns an array of the names of global variables.

global_variables.grep /std/   #=> [:$stdin, :$stdout, :$stderr]

Returns the names of the current local variables.

fred = 1
for i in 1..10
   # ...
end
local_variables   #=> [:fred, :i]

Returns the last Error of the current executing Thread or nil if none

Sets the last Error of the current executing Thread to error

Generate a JSON document from the Ruby data structure obj and return it. This method disables the checks for circles in Ruby objects.

WARNING: Be careful not to pass any Ruby data structures with circles as obj argument because this will cause JSON to go into an infinite loop.

Generate a JSON document from the Ruby data structure obj and return it. The returned document is a prettier form of the document returned by unparse.

The opts argument can be used to configure the generator. See the generate method for a more detailed explanation.

Returns garbage collector generation for the given object.

class B
  include ObjectSpace

  def foo
    trace_object_allocations do
      obj = Object.new
      p "Generation is #{allocation_generation(obj)}"
    end
  end
end

B.new.foo #=> "Generation is 3"

See ::trace_object_allocations for more information and examples.

Initiates garbage collection, unless manually disabled.

This method is defined with keyword arguments that default to true:

def GC.start(full_mark: true, immediate_sweep: true); end

Use full_mark: false to perform a minor GC. Use immediate_sweep: false to defer sweeping (use lazy sweep).

Note: These keyword arguments are implementation and version dependent. They are not guaranteed to be future-compatible, and may be ignored if the underlying implementation does not support them.

Parse a file at filename. Returns the Psych::Nodes::Document.

Raises a Psych::SyntaxError when a YAML syntax error is detected.

Parse a YAML string in yaml. Returns the Psych::Nodes::Stream. This method can handle multiple YAML documents contained in yaml. filename is used in the exception message if a Psych::SyntaxError is raised.

If a block is given, a Psych::Nodes::Document node will be yielded to the block as it’s being parsed.

Raises a Psych::SyntaxError when a YAML syntax error is detected.

Example:

Psych.parse_stream("---\n - a\n - b") # => #<Psych::Nodes::Stream:0x00>

Psych.parse_stream("--- a\n--- b") do |node|
  node # => #<Psych::Nodes::Document:0x00>
end

begin
  Psych.parse_stream("--- `", "file.txt")
rescue Psych::SyntaxError => ex
  ex.file    # => 'file.txt'
  ex.message # => "(file.txt): found character that cannot start any token"
end

See Psych::Nodes for more information about YAML AST.

Initiates garbage collection, unless manually disabled.

This method is defined with keyword arguments that default to true:

def GC.start(full_mark: true, immediate_sweep: true); end

Use full_mark: false to perform a minor GC. Use immediate_sweep: false to defer sweeping (use lazy sweep).

Note: These keyword arguments are implementation and version dependent. They are not guaranteed to be future-compatible, and may be ignored if the underlying implementation does not support them.

Start a dRuby server locally.

The new dRuby server will become the primary server, even if another server is currently the primary server.

uri is the URI for the server to bind to. If nil, the server will bind to random port on the default local host name and use the default dRuby protocol.

front is the server’s front object. This may be nil.

config is the configuration for the new server. This may be nil.

See DRbServer::new.

Start a dRuby server locally.

The new dRuby server will become the primary server, even if another server is currently the primary server.

uri is the URI for the server to bind to. If nil, the server will bind to random port on the default local host name and use the default dRuby protocol.

front is the server’s front object. This may be nil.

config is the configuration for the new server. This may be nil.

See DRbServer::new.

Get the ‘current’ server.

In the context of execution taking place within the main thread of a dRuby server (typically, as a result of a remote call on the server or one of its objects), the current server is that server. Otherwise, the current server is the primary server.

If the above rule fails to find a server, a DRbServerNotFound error is raised.

Get the ‘current’ server.

In the context of execution taking place within the main thread of a dRuby server (typically, as a result of a remote call on the server or one of its objects), the current server is that server. Otherwise, the current server is the primary server.

If the above rule fails to find a server, a DRbServerNotFound error is raised.

Returns true if the contents of a file A and a file B are identical.

FileUtils.compare_file('somefile', 'somefile')  #=> true
FileUtils.compare_file('/bin/cp', '/bin/mv')    #=> maybe false

Returns true if the contents of a file A and a file B are identical.

FileUtils.compare_file('somefile', 'somefile')  #=> true
FileUtils.compare_file('/bin/cp', '/bin/mv')    #=> maybe false