## winix-io--premicrothread.pkg
#
# A subpackage of winix_guts:
#
# src/lib/std/src/posix/winix-guts.pkg# Compiled by:
# src/lib/std/src/standard-core.sublibstipulate
package i1w = one_word_int_guts; # one_word_int_guts is from src/lib/std/src/one-word-int-guts.pkg package int = int_guts; # int_guts is from src/lib/std/src/int-guts.pkg package mig = multiword_int_guts; # multiword_int_guts is from src/lib/std/src/multiword-int-guts.pkg package psx = posixlib; # posixlib is from src/lib/std/src/psx/posixlib.pkg package tg = time_guts; # time_guts is from src/lib/std/src/time-guts.pkg package unt = unt_guts; # unt_guts is from src/lib/std/src/bind-unt-guts.pkg package wty = winix_types; # winix_types is from src/lib/std/src/posix/winix-types.pkg #
package ci = mythryl_callable_c_library_interface; # mythryl_callable_c_library_interface is from src/lib/std/src/unsafe/mythryl-callable-c-library-interface.pkg #
fun cfun fun_name # For background see Note[1] in src/lib/std/src/unsafe/mythryl-callable-c-library-interface.pkg =
ci::find_c_function'' { lib_name => "posix_os", fun_name };
herein
package winix_io__premicrothread
: (weak) Winix_Io__Premicrothread # Winix_Io__Premicrothread is from src/lib/std/src/winix/winix-io--premicrothread.api {
Iod = wty::io::Iod; # "Iod" == "I/O descriptor".
# An Iod is an abstract descriptor for an OS value that
# supports I/O e.g., file, tty device, socket, ....
# (In practice on posix it is an Int encoding a host-OS fd.)
Iod_Kind == wty::Iod_Kind;
# Return a hash value for the I/O descriptor:
#
fun hash fd
=
unt::from_int (wty::io::iod_to_fd fd);
# Compare two I/O descriptors:
#
fun compare (fd1, fd2)
=
int::compare
( wty::io::iod_to_fd fd1,
wty::io::iod_to_fd fd2
);
fun iod_to_iodkind io_descriptor # Return the kind of I/O descriptor.
=
{
i = wty::io::iod_to_fd io_descriptor;
fd = psx::int_to_fd i;
stat = psx::fstat fd;
if (psx::stat::is_file stat) wty::FILE;
elif (psx::stat::is_directory stat) wty::DIRECTORY;
elif (psx::stat::is_char_dev stat) wty::CHAR_DEVICE;
elif (psx::stat::is_block_dev stat) wty::BLOCK_DEVICE;
elif (psx::stat::is_symlink stat) wty::SYMLINK;
elif (psx::stat::is_pipe stat) wty::PIPE;
elif (psx::stat::is_socket stat) wty::SOCKET;
else wty::OTHER;
fi;
};
Ioplea
=
{ io_descriptor: Iod,
readable: Bool,
writable: Bool,
oobdable: Bool # Out-Of-Band-Data available on socket or PTY.
};
# Public representation of a polling operation on
# an I/O descriptor.
Ioplea_Result = Ioplea; # A synonym to clarify declarations.
exception BAD_WAIT_REQUEST;
(cfun "select") # select is from src/c/lib/posix-os/select.c
->
( poll__syscall: ( (List( (Int, Unt) ), # (fd, flags) pairs where 'flags' has three bits: readable/writable/oobdable
Null_Or( (i1w::Int, Int) )) # NULL or (THE timeout), where 'timeout' is a (seconds, microseconds) pair.
)
->
List( (Int, Unt) ), # Result list of (fd, flags) pairs, where 'flags' is nonzero (if zero, the pair is dropped from the result list).
poll__ref,
set__poll__ref
);
# 'wait_for_io_opportunity' checks to see which
# fds (of a given set) are ready for I/O:
#
stipulate
fun conditional_bit_or (FALSE, _, accumulator) => accumulator;
conditional_bit_or (TRUE, bit, accumulator) => unt::bitwise_or (accumulator, bit);
end;
fun test (word, bit)
=
(unt::bitwise_and (word, bit) != 0u0);
readable_bit = 0u1;
writable_bit = 0u2;
oobdable_bit = 0u4;
fun from_wait_request { io_descriptor, readable, writable, oobdable }
=
( wty::io::iod_to_fd io_descriptor,
conditional_bit_or
(
readable,
readable_bit,
conditional_bit_or
(
writable,
writable_bit,
conditional_bit_or
(
oobdable,
oobdable_bit,
0u0
)
)
)
);
fun to_poll_result (fd, w)
=
{ io_descriptor => wty::io::int_to_iod fd,
readable => test (w, readable_bit),
writable => test (w, writable_bit),
oobdable => test (w, oobdable_bit)
};
herein
fun wait_for_io_opportunity { wait_requests, timeout }
=
{
raw_results = *poll__ref (map from_wait_request wait_requests, timeout);
#
map to_poll_result raw_results;
}
where
timeout = case timeout
#
THE time => { usec = tg::to_microseconds time;
#
(mig::div_mod (usec, 1000000))
->
(sec, usec);
THE (i1w::from_multiword_int sec, int::from_multiword_int usec);
};
NULL => NULL;
esac;
end;
fun wait_for_io_opportunity__without_syscall_redirection { wait_requests, timeout } # Called (only) by server_loop() from src/lib/std/src/hostthread/io-wait-hostthread.pkg = # which is a secondary hostthread itself, hence has no need to redirect via a secondary hostthread.
{
raw_results = poll__syscall (map from_wait_request wait_requests, timeout);
#
map to_poll_result raw_results;
}
where
timeout = case timeout
#
THE time => { usec = tg::to_microseconds time;
#
(mig::div_mod (usec, 1000000))
->
(sec, usec);
THE (i1w::from_multiword_int sec, int::from_multiword_int usec);
};
NULL => NULL;
esac;
end;
end; # stipulate
}; # package winix_io__premicrothread
end;