From 813c5300294046f9ae0f4bac8449a4734ddd7fd9 Mon Sep 17 00:00:00 2001
From: Eric Wong <normalperson@yhbt.net>
Date: Sun, 27 Feb 2011 23:40:44 +0000
Subject: add IO.trytee interface

This allows more-efficient use of non-blocking I/O with
tee(2) and will return :EAGAIN instead of generating an
expensive Errno::EAGAIN exception.
---
 ext/io_splice/io_splice_ext.c | 47 +++++++++++++++++++++++++++++++------------
 1 file changed, 34 insertions(+), 13 deletions(-)

(limited to 'ext/io_splice')

diff --git a/ext/io_splice/io_splice_ext.c b/ext/io_splice/io_splice_ext.c
index 79d96ee..c97435e 100644
--- a/ext/io_splice/io_splice_ext.c
+++ b/ext/io_splice/io_splice_ext.c
@@ -222,6 +222,20 @@ static VALUE nogvl_tee(void *ptr)
 	return (VALUE)tee(a->fd_in, a->fd_out, a->len, a->flags);
 }
 
+static long do_tee(int argc, VALUE *argv, unsigned dflags)
+{
+	VALUE fd_in, fd_out, len, flags;
+	struct tee_args a;
+
+	rb_scan_args(argc, argv, "31", &fd_in, &fd_out, &len, &flags);
+	a.fd_in = my_fileno(fd_in);
+	a.fd_out = my_fileno(fd_out);
+	a.len = (size_t)NUM2ULONG(len);
+	a.flags = NIL_P(flags) ? dflags : NUM2UINT(flags) | dflags;
+
+	return (long)nb_io_run(nogvl_tee, &a, a.flags);
+}
+
 /*
  * call-seq:
  *   IO.tee(fd_in, fd_out, len, flags) => integer
@@ -241,19 +255,10 @@ static VALUE nogvl_tee(void *ptr)
  * See manpage for full documentation:
  * http://kernel.org/doc/man-pages/online/pages/man2/tee.2.html
  */
-static VALUE my_tee(VALUE self,
-	VALUE fd_in, VALUE fd_out,
-	VALUE len, VALUE flags)
+static VALUE my_tee(int argc, VALUE *argv, VALUE self)
 {
-	long n;
-	struct tee_args a = {
-		.fd_in = my_fileno(fd_in),
-		.fd_out = my_fileno(fd_out),
-		.len = (size_t)NUM2ULONG(len),
-		.flags = NUM2UINT(flags),
-	};
-
-	n = (long)nb_io_run(nogvl_tee, &a, a.flags);
+	long n = do_tee(argc, argv, 0);
+
 	if (n == 0)
 		rb_eof_error();
 	if (n < 0)
@@ -262,6 +267,21 @@ static VALUE my_tee(VALUE self,
 	return LONG2NUM(n);
 }
 
+static VALUE trytee(int argc, VALUE *argv, VALUE self)
+{
+	long n = do_tee(argc, argv, SPLICE_F_NONBLOCK);
+
+	if (n == 0)
+		return Qnil;
+	if (n < 0) {
+		if (errno == EAGAIN)
+			return sym_EAGAIN;
+		rb_sys_fail("tee");
+	}
+
+	return LONG2NUM(n);
+}
+
 struct vmsplice_args {
 	int fd;
 	struct iovec *iov;
@@ -472,7 +492,8 @@ void Init_io_splice_ext(void)
 
 	rb_define_singleton_method(rb_cIO, "splice", my_splice, -1);
 	rb_define_singleton_method(rb_cIO, "trysplice", trysplice, -1);
-	rb_define_singleton_method(rb_cIO, "tee", my_tee, 4);
+	rb_define_singleton_method(rb_cIO, "tee", my_tee, -1);
+	rb_define_singleton_method(rb_cIO, "trytee", trytee, -1);
 	rb_define_singleton_method(rb_cIO, "vmsplice", my_vmsplice, 3);
 
 	/*
-- 
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