Implement IO.pipe

README.md

@@ -16,7 +16,7 @@ IO, File module for mruby
 | IO.copy_stream             |          |      |
 | IO.new, IO.for_fd, IO.open |  o  |     |
 | IO.foreach                 |          |      |
-| IO.pipe                    |          |      |
+| IO.pipe                    |    o     |      |
 | IO.popen                   |    o     |      |
 | IO.read                    |    o     |      |
 | IO.readlines               |          |      |

mrblib/io.rb

@@ -41,6 +41,19 @@ class IO
     end
   end
 
+  def self.pipe(&block)
+    if block
+      begin
+        r, w = IO._pipe
+        yield r, w
+      ensure
+        r.close unless r.closed?
+        w.close unless w.closed?
+      end
+    else
+      IO._pipe
+    end
+  end
 
   def self.read(path, length=nil, offset=nil, opt=nil)
     if not opt.nil?        # 4 arguments

src/io.c

@@ -149,6 +149,32 @@ mrb_fd_cloexec(mrb_state *mrb, int fd)
 #endif
 }
 
+static int
+mrb_cloexec_pipe(mrb_state *mrb, int fildes[2])
+{
+  int ret;
+  ret = pipe(fildes);
+  if (ret == -1)
+    return -1;
+  mrb_fd_cloexec(mrb, fildes[0]);
+  mrb_fd_cloexec(mrb, fildes[1]);
+  return ret;
+}
+
+static int
+mrb_pipe(mrb_state *mrb, int pipes[2])
+{
+  int ret;
+  ret = mrb_cloexec_pipe(mrb, pipes);
+  if (ret == -1) {
+    if (errno == EMFILE || errno == ENFILE) {
+      mrb_garbage_collect(mrb);
+      ret = mrb_cloexec_pipe(mrb, pipes);
+    }
+  }
+  return ret;
+}
+
 #ifndef _WIN32
 static int
 mrb_proc_exec(const char *pname)
@@ -644,6 +670,42 @@ mrb_io_read_data_pending(mrb_state *mrb, mrb_value io)
   return 0;
 }
 
+static mrb_value
+mrb_io_s_pipe(mrb_state *mrb, mrb_value klass)
+{
+  mrb_value r = mrb_nil_value();
+  mrb_value w = mrb_nil_value();
+  struct mrb_io *fptr_r;
+  struct mrb_io *fptr_w;
+  int pipes[2];
+
+  if (mrb_pipe(mrb, pipes) == -1) {
+    mrb_sys_fail(mrb, "pipe");
+  }
+
+  r = mrb_obj_value(mrb_data_object_alloc(mrb, mrb_class_ptr(klass), NULL, &mrb_io_type));
+  mrb_iv_set(mrb, r, mrb_intern_cstr(mrb, "@buf"), mrb_str_new_cstr(mrb, ""));
+  mrb_iv_set(mrb, r, mrb_intern_cstr(mrb, "@pos"), mrb_fixnum_value(0));
+  fptr_r = mrb_io_alloc(mrb);
+  fptr_r->fd = pipes[0];
+  fptr_r->writable = 0;
+  fptr_r->sync = 0;
+  DATA_TYPE(r) = &mrb_io_type;
+  DATA_PTR(r)  = fptr_r;
+
+  w = mrb_obj_value(mrb_data_object_alloc(mrb, mrb_class_ptr(klass), NULL, &mrb_io_type));
+  mrb_iv_set(mrb, w, mrb_intern_cstr(mrb, "@buf"), mrb_str_new_cstr(mrb, ""));
+  mrb_iv_set(mrb, w, mrb_intern_cstr(mrb, "@pos"), mrb_fixnum_value(0));
+  fptr_w = mrb_io_alloc(mrb);
+  fptr_w->fd = pipes[1];
+  fptr_w->writable = 1;
+  fptr_w->sync = 1;
+  DATA_TYPE(w) = &mrb_io_type;
+  DATA_PTR(w)  = fptr_w;
+
+  return mrb_assoc_new(mrb, r, w);
+}
+
 static mrb_value
 mrb_io_s_select(mrb_state *mrb, mrb_value klass)
 {
@@ -925,6 +987,7 @@ mrb_init_io(mrb_state *mrb)
   mrb_define_class_method(mrb, io, "for_fd",  mrb_io_s_for_fd,   MRB_ARGS_ANY());
   mrb_define_class_method(mrb, io, "select",  mrb_io_s_select,  MRB_ARGS_ANY());
   mrb_define_class_method(mrb, io, "sysopen", mrb_io_s_sysopen, MRB_ARGS_ANY());
+  mrb_define_class_method(mrb, io, "_pipe", mrb_io_s_pipe, MRB_ARGS_NONE());
 
   mrb_define_method(mrb, io, "initialize", mrb_io_initialize, MRB_ARGS_ANY());    /* 15.2.20.5.21 (x)*/
   mrb_define_method(mrb, io, "sync",       mrb_io_sync,       MRB_ARGS_NONE());

test/io.rb

@@ -402,28 +402,23 @@ assert('IO#close_on_exec') do
   io.close
   io.closed?
 
-  # # Use below when IO.pipe is implemented.
-  # begin
-  #   r, w = IO.pipe
-  #   assert_equal(false, r.close_on_exec?)
-  #   r.close_on_exec = true
-  #   assert_equal(true, r.close_on_exec?)
-  #   r.close_on_exec = false
-  #   assert_equal(false, r.close_on_exec?)
-  #   r.close_on_exec = true
-  #   assert_equal(true, r.close_on_exec?)
-
-  #   assert_equal(false, w.close_on_exec?)
-  #   w.close_on_exec = true
-  #   assert_equal(true, w.close_on_exec?)
-  #   w.close_on_exec = false
-  #   assert_equal(false, w.close_on_exec?)
-  #   w.close_on_exec = true
-  #   assert_equal(true, w.close_on_exec?)
-  # ensure
-  #   r.close unless r.closed?
-  #   w.close unless w.closed?
-  # end
+  begin
+    r, w = IO.pipe
+    assert_equal(true, r.close_on_exec?)
+    r.close_on_exec = false
+    assert_equal(false, r.close_on_exec?)
+    r.close_on_exec = true
+    assert_equal(true, r.close_on_exec?)
+
+    assert_equal(true, w.close_on_exec?)
+    w.close_on_exec = false
+    assert_equal(false, w.close_on_exec?)
+    w.close_on_exec = true
+    assert_equal(true, w.close_on_exec?)
+  ensure
+    r.close unless r.closed?
+    w.close unless w.closed?
+  end
 end
 
 assert('IO#sysseek') do
@@ -434,6 +429,42 @@ assert('IO#sysseek') do
   end
 end
 
+assert('IO.pipe') do
+  called = false
+  IO.pipe do |r, w|
+    assert_true r.kind_of?(IO)
+    assert_true w.kind_of?(IO)
+    assert_false r.closed?
+    assert_false w.closed?
+    assert_true FileTest.pipe?(r)
+    assert_true FileTest.pipe?(w)
+    assert_nil r.pid
+    assert_nil w.pid
+    assert_true 2 < r.fileno
+    assert_true 2 < w.fileno
+    assert_true r.fileno != w.fileno
+    assert_false r.sync
+    assert_true w.sync
+    assert_equal 8, w.write('test for')
+    assert_equal 'test', r.read(4)
+    assert_equal ' for', r.read(4)
+    assert_equal 5, w.write(' pipe')
+    assert_equal nil, w.close
+    assert_equal ' pipe', r.read
+    called = true
+    assert_raise(IOError) { r.write 'test' }
+    # TODO:
+    # This assert expect raise IOError but got RuntimeError
+    # Because mruby-io not have flag for I/O readable
+    # assert_raise(IOError) { w.read }
+  end
+  assert_true called
+
+  assert_nothing_raised do
+    IO.pipe { |r, w| r.close; w.close }
+  end
+end
+
 assert('`cmd`') do
   assert_equal `echo foo`, "foo\n"
 end