1 files changed, 106 insertions, 1 deletions

diff --git a/internal/io.h b/internal/io.h
index b184cec439..1891248a19 100644
--- a/internal/io.h
+++ b/internal/io.h
@@ -1,7 +1,6 @@
 #ifndef INTERNAL_IO_H                                    /*-*-C-*-vi:se ft=c:*/
 #define INTERNAL_IO_H
 /**
- * @file
  * @author     Ruby developers <ruby-core@ruby-lang.org>
  * @copyright  This  file  is   a  part  of  the   programming  language  Ruby.
  *             Permission  is hereby  granted,  to  either redistribute  and/or
@@ -10,8 +9,110 @@
  * @brief      Internal header for IO.
  */
 #include "ruby/ruby.h"          /* for VALUE */
+
+#define HAVE_RB_IO_T
+struct rb_io;
+
 #include "ruby/io.h"            /* for rb_io_t */
 
+#define IO_WITHOUT_GVL(func, arg) rb_thread_call_without_gvl(func, arg, RUBY_UBF_IO, 0)
+#define IO_WITHOUT_GVL_INT(func, arg) (int)(VALUE)IO_WITHOUT_GVL(func, arg)
+
+/** Ruby's IO, metadata and buffers. */
+struct rb_io {
+
+    /** The IO's Ruby level counterpart. */
+    VALUE self;
+
+    /** stdio ptr for read/write, if available. */
+    FILE *stdio_file;
+
+    /** file descriptor. */
+    int fd;
+
+    /** mode flags: FMODE_XXXs */
+    int mode;
+
+    /** child's pid (for pipes) */
+    rb_pid_t pid;
+
+    /** number of lines read */
+    int lineno;
+
+    /** pathname for file */
+    VALUE pathv;
+
+    /** finalize proc */
+    void (*finalize)(struct rb_io*,int);
+
+    /** Write buffer. */
+    rb_io_buffer_t wbuf;
+
+    /**
+     * (Byte)  read   buffer.   Note  also   that  there  is  a   field  called
+     * ::rb_io_t::cbuf, which also concerns read IO.
+     */
+    rb_io_buffer_t rbuf;
+
+    /**
+     * Duplex IO object, if set.
+     *
+     * @see rb_io_set_write_io()
+     */
+    VALUE tied_io_for_writing;
+
+    struct rb_io_encoding encs; /**< Decomposed encoding flags. */
+
+    /** Encoding converter used when reading from this IO. */
+    rb_econv_t *readconv;
+
+    /**
+     * rb_io_ungetc()  destination.   This  buffer   is  read  before  checking
+     * ::rb_io_t::rbuf
+     */
+    rb_io_buffer_t cbuf;
+
+    /** Encoding converter used when writing to this IO. */
+    rb_econv_t *writeconv;
+
+    /**
+     * This is, when set, an instance  of ::rb_cString which holds the "common"
+     * encoding.   Write  conversion  can  convert strings  twice...   In  case
+     * conversion from encoding  X to encoding Y does not  exist, Ruby finds an
+     * encoding Z that bridges the two, so that X to Z to Y conversion happens.
+     */
+    VALUE writeconv_asciicompat;
+
+    /** Whether ::rb_io_t::writeconv is already set up. */
+    int writeconv_initialized;
+
+    /**
+     * Value   of    ::rb_io_t::rb_io_enc_t::ecflags   stored    right   before
+     * initialising ::rb_io_t::writeconv.
+     */
+    int writeconv_pre_ecflags;
+
+    /**
+     * Value of ::rb_io_t::rb_io_enc_t::ecopts stored right before initialising
+     * ::rb_io_t::writeconv.
+     */
+    VALUE writeconv_pre_ecopts;
+
+    /**
+     * This is a Ruby  level mutex.  It avoids multiple threads  to write to an
+     * IO at  once; helps  for instance rb_io_puts()  to ensure  newlines right
+     * next to its arguments.
+     *
+     * This of course doesn't help inter-process IO interleaves, though.
+     */
+    VALUE write_lock;
+
+    /**
+     * The timeout associated with this IO when performing blocking operations.
+     */
+    VALUE timeout;
+};
+
 /* io.c */
 void ruby_set_inplace_mode(const char *);
 void rb_stdio_set_default_encoding(void);
@@ -25,6 +126,10 @@ void rb_io_fptr_finalize_internal(void *ptr);
 #define rb_io_fptr_finalize rb_io_fptr_finalize_internal
 VALUE rb_io_popen(VALUE pname, VALUE pmode, VALUE env, VALUE opt);
 
+VALUE rb_io_prep_stdin(void);
+VALUE rb_io_prep_stdout(void);
+VALUE rb_io_prep_stderr(void);
+
 RUBY_SYMBOL_EXPORT_BEGIN
 /* io.c (export) */
 void rb_maygvl_fd_fix_cloexec(int fd);