/
file_descriptor.cr
186 lines (150 loc) · 3.63 KB
/
file_descriptor.cr
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require "crystal/system/file_descriptor"
# An `IO` over a file descriptor.
class IO::FileDescriptor < IO
include Crystal::System::FileDescriptor
include IO::Buffered
# The raw file-descriptor. It is defined to be an `Int`, but its size is
# platform-specific.
getter fd
def initialize(@fd, blocking = false)
@closed = system_closed?
unless blocking || {{flag?(:win32)}}
self.blocking = false
end
end
# :nodoc:
def self.from_stdio(fd)
# If we have a TTY for stdin/out/err, it is possibly a shared terminal.
# We need to reopen it to use O_NONBLOCK without causing other programs to break
# Figure out the terminal TTY name. If ttyname fails we have a non-tty, or something strange.
path = uninitialized UInt8[256]
ret = LibC.ttyname_r(fd, path, 256)
return new(fd, blocking: true) unless ret == 0
clone_fd = LibC.open(path, LibC::O_RDWR)
return new(fd, blocking: true) if clone_fd == -1
# We don't buffer output for TTY devices to see their output right away
io = new(clone_fd)
io.close_on_exec = true
io.sync = true
io
end
def blocking
system_blocking?
end
def blocking=(value)
self.system_blocking = value
end
def close_on_exec?
system_close_on_exec?
end
def close_on_exec=(value : Bool)
self.system_close_on_exec = value
end
{% unless flag?(:win32) %}
def self.fcntl(fd, cmd, arg = 0)
Crystal::System::FileDescriptor.fcntl(fd, cmd, arg)
end
def fcntl(cmd, arg = 0)
Crystal::System::FileDescriptor.fcntl(@fd, cmd, arg)
end
{% end %}
def info
system_info
end
# Seeks to a given *offset* (in bytes) according to the *whence* argument.
# Returns `self`.
#
# ```
# File.write("testfile", "abc")
#
# file = File.new("testfile")
# file.gets(3) # => "abc"
# file.seek(1, IO::Seek::Set)
# file.gets(2) # => "bc"
# file.seek(-1, IO::Seek::Current)
# file.gets(1) # => "c"
# ```
def seek(offset, whence : Seek = Seek::Set)
check_open
flush
offset -= @in_buffer_rem.size if whence.current?
system_seek(offset, whence)
@in_buffer_rem = Bytes.empty
self
end
# Same as `seek` but yields to the block after seeking and eventually seeks
# back to the original position when the block returns.
def seek(offset, whence : Seek = Seek::Set)
original_pos = tell
begin
seek(offset, whence)
yield
ensure
seek(original_pos)
end
end
# Returns the current position (in bytes) in this `IO`.
#
# ```
# File.write("testfile", "hello")
#
# file = File.new("testfile")
# file.pos # => 0
# file.gets(2) # => "he"
# file.pos # => 2
# ```
def pos
check_open
system_pos - @in_buffer_rem.size
end
# Sets the current position (in bytes) in this `IO`.
#
# ```
# File.write("testfile", "hello")
#
# file = File.new("testfile")
# file.pos = 3
# file.gets_to_end # => "lo"
# ```
def pos=(value)
seek value
value
end
def finalize
return if closed?
close rescue nil
end
def closed?
@closed
end
def tty?
system_tty?
end
def reopen(other : IO::FileDescriptor)
return other if self.fd == other.fd
system_reopen(other)
other
end
def inspect(io : IO) : Nil
io << "#<IO::FileDescriptor:"
if closed?
io << "(closed)"
else
io << " fd=" << @fd
end
io << '>'
end
def pretty_print(pp)
pp.text inspect
end
private def unbuffered_rewind
self.pos = 0
end
private def unbuffered_close
return if @closed
system_close ensure @closed = true
end
private def unbuffered_flush
# Nothing
end
end