/
kernel.cr
203 lines (178 loc) · 4.25 KB
/
kernel.cr
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require "c/unistd"
STDIN = IO::FileDescriptor.new(0, blocking: LibC.isatty(0) == 0)
STDOUT = (IO::FileDescriptor.new(1, blocking: LibC.isatty(1) == 0)).tap { |f| f.flush_on_newline = true }
STDERR = (IO::FileDescriptor.new(2, blocking: LibC.isatty(2) == 0)).tap { |f| f.flush_on_newline = true }
PROGRAM_NAME = String.new(ARGV_UNSAFE.value)
ARGV = (ARGV_UNSAFE + 1).to_slice(ARGC_UNSAFE - 1).map { |c_str| String.new(c_str) }
ARGF = IO::ARGF.new(ARGV, STDIN)
# Repeatedly executes the block, passing an incremental `Int32`
# that starts with `0`.
#
# ```
# loop do |i|
# print "#{i}) "
# line = gets
# break unless line
# # ...
# end
# ```
def loop
i = 0
while true
yield i
i += 1
end
end
# Reads a line from `STDIN`.
#
# See also: `IO#gets`.
def gets(*args, **options)
STDIN.gets(*args, **options)
end
# Reads a line from `STDIN`.
#
# See also: `IO#read_line`.
def read_line(*args, **options)
STDIN.read_line(*args, **options)
end
# Prints objects to STDOUT and then invokes `STDOUT.flush`.
#
# See also: `IO#print`.
def print(*objects : _) : Nil
STDOUT.print *objects
STDOUT.flush
end
# Prints a formatted string to `STDOUT`.
#
# See also: `IO#printf`.
def printf(format_string, *args) : Nil
printf format_string, args
end
# ditto
def printf(format_string, args : Array | Tuple) : Nil
STDOUT.printf format_string, args
end
# Returns a formatted string.
#
# See also: `IO#printf`.
def sprintf(format_string, *args) : String
sprintf format_string, args
end
# ditto
def sprintf(format_string, args : Array | Tuple) : String
String.build(format_string.bytesize) do |str|
String::Formatter(typeof(args)).new(format_string, args, str).format
end
end
# Prints objects to `STDOUT`, each followed by a newline.
#
# See also: `IO#puts`.
def puts(*objects) : Nil
STDOUT.puts *objects
end
# Pretty prints *object* to `STDOUT` followed
# by a newline. Returns *object*.
#
# See also: `Object#pretty_print(pp)`.
def p(object)
PrettyPrint.format(object, STDOUT, 79)
puts
object
end
# Pretty prints each object in *objects* to `STDOUT`, followed
# by a newline. Returns *objects*.
#
# See also: `Object#pretty_print(pp)`.
def p(*objects)
objects.each do |obj|
p obj
end
objects
end
# Pretty prints each object in *objects* to `STDOUT`, followed
# by a newline. Returns *objects*.
#
# ```
# p foo: 23, bar: 42 # => {foo: 23, bar: 42}
# ```
#
# See `Object#pretty_print(pp)`
def p(**objects)
p(objects)
end
# :nodoc:
module AtExitHandlers
@@running = false
def self.add(handler)
handlers = @@handlers ||= [] of Int32 ->
handlers << handler
end
def self.run(status)
return if @@running
@@running = true
@@handlers.try &.reverse_each do |handler|
begin
handler.call status
rescue handler_ex
STDERR.puts "Error running at_exit handler: #{handler_ex}"
end
end
end
end
# Registers the given `Proc` for execution when the program exits.
# If multiple handlers are registered, they are executed in reverse order of registration.
#
# ```
# def do_at_exit(str1)
# at_exit { print str1 }
# end
#
# at_exit { puts "cruel world" }
# do_at_exit("goodbye ")
# exit
# ```
#
# Produces:
#
# ```text
# goodbye cruel world
# ```
def at_exit(&handler : Int32 ->) : Nil
AtExitHandlers.add(handler)
end
# Terminates execution immediately, returning the given status code
# to the invoking environment.
#
# Registered `at_exit` procs are executed.
def exit(status = 0) : NoReturn
AtExitHandlers.run status
STDOUT.flush
STDERR.flush
Process.exit(status)
end
# Terminates execution immediately, printing *message* to `STDERR` and
# then calling `exit(status)`.
def abort(message, status = 1) : NoReturn
STDERR.puts message if message
exit status
end
class Process
# Hooks are defined here due to load order problems.
def self.after_fork_child_callbacks
@@after_fork_child_callbacks ||= [
->{ Scheduler.after_fork; nil },
->{ Event::SignalHandler.after_fork; nil },
->{ Event::SignalChildHandler.instance.after_fork; nil },
->{ Random::DEFAULT.new_seed; nil },
] of -> Nil
end
end
Signal.setup_default_handlers
at_exit { Event::SignalHandler.close }
# Background loop to cleanup unused fiber stacks.
spawn do
loop do
sleep 5
Fiber.stack_pool_collect
end
end