Enable option :in, :out, :err

mrblib/io.rb

@@ -26,11 +26,11 @@ class IO
     end
   end
 
-  def self.popen(command, mode = 'r', &block)
+  def self.popen(command, mode = 'r', opts={}, &block)
     if !self.respond_to?(:_popen)
       raise NotImplementedError, "popen is not supported on this platform"
     end
-    io = self._popen(command, mode)
+    io = self._popen(command, mode, opts)
     return io unless block
 
     begin

src/io.c

@@ -270,6 +270,7 @@ mrb_io_s_popen(mrb_state *mrb, mrb_value klass)
   mrb_value cmd, io, result;
   mrb_value mode = mrb_str_new_cstr(mrb, "r");
   mrb_value opt  = mrb_hash_new(mrb);
+  mrb_value opt_in, opt_out, opt_err;
 
   struct mrb_io *fptr;
   const char *pname;
@@ -315,6 +316,18 @@ mrb_io_s_popen(mrb_state *mrb, mrb_value klass)
   result = mrb_nil_value();
   switch (pid = fork()) {
     case 0: /* child */
+      opt_in = mrb_funcall(mrb, opt, "[]", 1, mrb_symbol_value(mrb_intern_lit(mrb, "in")));
+      opt_out = mrb_funcall(mrb, opt, "[]", 1, mrb_symbol_value(mrb_intern_lit(mrb, "out")));
+      opt_err = mrb_funcall(mrb, opt, "[]", 1, mrb_symbol_value(mrb_intern_lit(mrb, "err")));
+      if (!mrb_nil_p(opt_in)) {
+        dup2(mrb_fixnum(mrb_io_fileno(mrb, opt_in)), 0);
+      }
+      if (!mrb_nil_p(opt_out)) {
+        dup2(mrb_fixnum(mrb_io_fileno(mrb, opt_out)), 1);
+      }
+      if (!mrb_nil_p(opt_err)) {
+        dup2(mrb_fixnum(mrb_io_fileno(mrb, opt_err)), 2);
+      }
       if (flags & FMODE_READABLE) {
         close(pr[0]);
         if (pr[1] != 1) {

test/io.rb

@@ -393,6 +393,43 @@ assert('IO.popen') do
   end
 end
 
+assert('IO.popen with in option') do
+  begin
+    IO.pipe do |r, w|
+      w.write 'hello'
+      w.close
+      assert_equal "hello", IO.popen("cat", "r", in: r) { |i| i.read }
+      assert_equal "", r.read
+    end
+  rescue NotImplementedError => e
+    skip e.message
+  end
+end
+
+assert('IO.popen with out option') do
+  begin
+    IO.pipe do |r, w|
+      IO.popen("echo 'hello'", "w", out: w) {}
+      w.close
+      assert_equal "hello\n", r.read
+    end
+  rescue NotImplementedError => e
+    skip e.message
+  end
+end
+
+assert('IO.popen with err option') do
+  begin
+    IO.pipe do |r, w|
+      assert_equal "", IO.popen("echo 'hello' 1>&2", "r", err: w) { |i| i.read }
+      w.close
+      assert_equal "hello\n", r.read
+    end
+  rescue NotImplementedError => e
+    skip e.message
+  end
+end
+
 assert('IO.read') do
   # empty file
   fd = IO.sysopen $mrbtest_io_wfname, "w"