Eliminate make_cleanup_ui_file_delete / make ui_file a class hierarchy

This patch starts from the desire to eliminate
make_cleanup_ui_file_delete, but then goes beyond.  It makes ui_file &
friends a real C++ class hierarchy, and switches temporary
ui_file-like objects to stack-based allocation.

- mem_fileopen -> string_file

mem_fileopen is replaced with a new string_file class that is treated
as a value class created on the stack.  This alone eliminates most
make_cleanup_ui_file_delete calls, and, simplifies code a whole lot
(diffstat shows around 1k loc dropped.)

string_file's internal buffer is a std::string, thus the "string" in
the name.  This simplifies the implementation much, compared to
mem_fileopen, which managed growing its internal buffer manually.

- ui_file_as_string, ui_file_strdup, ui_file_obsavestring all gone

The new string_file class has a string() method that provides direct
writable access to the internal std::string buffer.  This replaced
ui_file_as_string, which forced a copy of the same data the stream had
inside.  With direct access via a writable reference, we can instead
move the string out of the string_stream, avoiding deep string
copying.

Related, ui_file_xstrdup calls are replaced with xstrdup'ping the
stream's string, and ui_file_obsavestring is replaced by
obstack_copy0.

With all those out of the way, getting rid of the weird ui_file_put
mechanism was possible.

- New ui_file::printf, ui_file::puts, etc. methods

These simplify / clarify client code.  I considered splitting
client-code changes, like these, e.g.:

  -  stb = mem_fileopen ();
  -  fprintf_unfiltered (stb, "%s%s%s",
  -		      _("The valid values are:\n"),
  -		      regdesc,
  -		      _("The default is \"std\"."));
  +  string_file stb;
  +  stb.printf ("%s%s%s",
  +	      _("The valid values are:\n"),
  +	      regdesc,
  +	      _("The default is \"std\"."));

In two steps, with the first step leaving fprintf_unfiltered (etc.)
calls in place, and only afterwards do a pass to change all those to
call stb.printf etc..  I didn't do that split, because (when I tried),
it turned out to be pointless make-work: the first pass would have to
touch the fprintf_unfiltered line anyway, to replace "stb" with
"&stb".

- gdb_fopen replaced with stack-based objects

This avoids the need for cleanups or unique_ptr's.  I.e., this:

      struct ui_file *file = gdb_fopen (filename, "w");
      if (filename == NULL)
 	perror_with_name (filename);
      cleanups = make_cleanup_ui_file_delete (file);
      // use file.
      do_cleanups (cleanups);

is replaced with this:

      stdio_file file;
      if (!file.open (filename, "w"))
 	perror_with_name (filename);
      // use file.

- odd contorsions in null_file_write / null_file_fputs around when to
  call to_fputs / to_write eliminated.

- Global null_stream object

A few places that were allocating a ui_file in order to print to
"nowhere" are adjusted to instead refer to a new 'null_stream' global
stream.

- TUI's tui_sfileopen eliminated.  TUI's ui_file much simplified

The TUI's ui_file was serving a dual purpose.  It supported being used
as string buffer, and supported being backed by a stdio FILE.  The
string buffer part is gone, replaced by using of string_file.  The
'FILE *' support is now much simplified, by making the TUI's ui_file
inherit from stdio_file.

gdb/ChangeLog:
2017-02-02  Pedro Alves  <palves@redhat.com>

	* ada-lang.c (type_as_string): Use string_file.
	* ada-valprint.c (ada_print_floating): Use string_file.
	* ada-varobj.c (ada_varobj_scalar_image)
	(ada_varobj_get_value_image): Use string_file.
	* aix-thread.c (aix_thread_extra_thread_info): Use string_file.
	* arm-tdep.c (_initialize_arm_tdep): Use string_printf.
	* breakpoint.c (update_inserted_breakpoint_locations)
	(insert_breakpoint_locations, reattach_breakpoints)
	(print_breakpoint_location, print_one_detail_ranged_breakpoint)
	(print_it_watchpoint): Use string_file.
	(save_breakpoints): Use stdio_file.
	* c-exp.y (oper): Use string_file.
	* cli/cli-logging.c (set_logging_redirect): Use ui_file_up and
	tee_file.
	(pop_output_files): Use delete.
	(handle_redirections): Use stdio_file and tee_file.
	* cli/cli-setshow.c (do_show_command): Use string_file.
	* compile/compile-c-support.c (c_compute_program): Use
	string_file.
	* compile/compile-c-symbols.c (generate_vla_size): Take a
	'string_file &' instead of a 'ui_file *'.
	(generate_c_for_for_one_variable): Take a 'string_file &' instead
	of a 'ui_file *'.  Use string_file.
	(generate_c_for_variable_locations): Take a 'string_file &'
	instead of a 'ui_file *'.
	* compile/compile-internal.h (generate_c_for_for_one_variable):
	Take a 'string_file &' instead of a 'ui_file *'.
	* compile/compile-loc2c.c (push, pushf, unary, binary)
	(print_label, pushf_register_address, pushf_register)
	(do_compile_dwarf_expr_to_c): Take a 'string_file &' instead of a
	'ui_file *'.  Adjust.
	* compile/compile.c (compile_to_object): Use string_file.
	* compile/compile.h (compile_dwarf_expr_to_c)
	(compile_dwarf_bounds_to_c): Take a 'string_file &' instead of a
	'ui_file *'.
	* cp-support.c (inspect_type): Use string_file and obstack_copy0.
	(replace_typedefs_qualified_name): Use string_file and
	obstack_copy0.
	* disasm.c (gdb_pretty_print_insn): Use string_file.
	(gdb_disassembly): Adjust reference the null_stream global.
	(do_ui_file_delete): Delete.
	(gdb_insn_length): Use null_stream.
	* dummy-frame.c (maintenance_print_dummy_frames): Use stdio_file.
	* dwarf2loc.c (dwarf2_compile_property_to_c)
	(locexpr_generate_c_location, loclist_generate_c_location): Take a
	'string_file &' instead of a 'ui_file *'.
	* dwarf2loc.h (dwarf2_compile_property_to_c): Likewise.
	* dwarf2read.c (do_ui_file_peek_last): Delete.
	(dwarf2_compute_name): Use string_file.
	* event-top.c (gdb_setup_readline): Use stdio_file.
	* gdbarch.sh (verify_gdbarch): Use string_file.
	* gdbtypes.c (safe_parse_type): Use null_stream.
	* guile/scm-breakpoint.c (gdbscm_breakpoint_commands): Use
	string_file.
	* guile/scm-disasm.c (gdbscm_print_insn_from_port): Take a
	'string_file *' instead of a 'ui_file *'.
	(gdbscm_arch_disassemble): Use string_file.
	* guile/scm-frame.c (frscm_print_frame_smob): Use string_file.
	* guile/scm-ports.c (class ioscm_file_port): Now a class that
	inherits from ui_file.
	(ioscm_file_port_delete, ioscm_file_port_rewind)
	(ioscm_file_port_put): Delete.
	(ioscm_file_port_write): Rename to ...
	(ioscm_file_port::write): ... this.  Remove file_port_magic
	checks.
	(ioscm_file_port_new): Delete.
	(ioscm_with_output_to_port_worker): Use ioscm_file_port and
	ui_file_up.
	* guile/scm-type.c (tyscm_type_name): Use string_file.
	* guile/scm-value.c (vlscm_print_value_smob, gdbscm_value_print):
	Use string_file.
	* infcmd.c (print_return_value_1): Use string_file.
	* infrun.c (print_target_wait_results): Use string_file.
	* language.c (add_language): Use string_file.
	* location.c (explicit_to_string_internal): Use string_file.
	* main.c (captured_main_1): Use null_file.
	* maint.c (maintenance_print_architecture): Use stdio_file.
	* mi/mi-cmd-stack.c (list_arg_or_local): Use string_file.
	* mi/mi-common.h (struct mi_interp) <out, err, log, targ,
	event_channel>: Change type to mi_console_file pointer.
	* mi/mi-console.c (mi_console_file_fputs, mi_console_file_flush)
	(mi_console_file_delete): Delete.
	(struct mi_console_file): Delete.
	(mi_console_file_magic): Delete.
	(mi_console_file_new): Delete.
	(mi_console_file::mi_console_file): New.
	(mi_console_file_delete): Delete.
	(mi_console_file_fputs): Delete.
	(mi_console_file::write): New.
	(mi_console_raw_packet): Delete.
	(mi_console_file::flush): New.
	(mi_console_file_flush): Delete.
	(mi_console_set_raw): Rename to ...
	(mi_console_file::set_raw): ... this.
	* mi/mi-console.h (class mi_console_file): New class.
	(mi_console_file_new, mi_console_set_raw): Delete.
	* mi/mi-interp.c (mi_interpreter_init): Use mi_console_file.
	(mi_set_logging): Use delete and tee_file.  Adjust.
	* mi/mi-main.c (output_register): Use string_file.
	(mi_cmd_data_evaluate_expression): Use string_file.
	(mi_cmd_data_read_memory): Use string_file.
	(mi_cmd_execute, print_variable_or_computed): Use string_file.
	* mi/mi-out.c (mi_ui_out::main_stream): New.
	(mi_ui_out::rewind): Use main_stream and
	string_file.
	(mi_ui_out::put): Use main_stream and string_file.
	(mi_ui_out::mi_ui_out): Remove 'stream' parameter.
	Allocate a 'string_file' instead.
	(mi_out_new): Don't allocate a mem_fileopen stream here.
	* mi/mi-out.h (mi_ui_out::mi_ui_out): Remove 'stream' parameter.
	(mi_ui_out::main_stream): Declare method.
	* printcmd.c (eval_command): Use string_file.
	* psymtab.c (maintenance_print_psymbols): Use stdio_file.
	* python/py-arch.c (archpy_disassemble): Use string_file.
	* python/py-breakpoint.c (bppy_get_commands): Use string_file.
	* python/py-frame.c (frapy_str): Use string_file.
	* python/py-framefilter.c (py_print_type, py_print_single_arg):
	Use string_file.
	* python/py-type.c (typy_str): Use string_file.
	* python/py-unwind.c (unwind_infopy_str): Use string_file.
	* python/py-value.c (valpy_str): Use string_file.
	* record-btrace.c (btrace_insn_history): Use string_file.
	* regcache.c (regcache_print): Use stdio_file.
	* reggroups.c (maintenance_print_reggroups): Use stdio_file.
	* remote.c (escape_buffer): Use string_file.
	* rust-lang.c (rust_get_disr_info): Use string_file.
	* serial.c (serial_open_ops_1): Use stdio_file.
	(do_serial_close): Use delete.
	* stack.c (print_frame_arg): Use string_file.
	(print_frame_args): Remove local mem_fileopen stream, not used.
	(print_frame): Use string_file.
	* symmisc.c (maintenance_print_symbols): Use stdio_file.
	* symtab.h (struct symbol_computed_ops) <generate_c_location>:
	Take a 'string_file *' instead of a 'ui_file *'.
	* top.c (new_ui): Use stdio_file and stderr_file.
	(free_ui): Use delete.
	(execute_command_to_string): Use string_file.
	(quit_confirm): Use string_file.
	* tracepoint.c (collection_list::append_exp): Use string_file.
	* tui/tui-disasm.c (tui_disassemble): Use string_file.
	* tui/tui-file.c: Don't include "ui-file.h".
	(enum streamtype, struct tui_stream): Delete.
	(tui_file_new, tui_file_delete, tui_fileopen, tui_sfileopen)
	(tui_file_isatty, tui_file_rewind, tui_file_put): Delete.
	(tui_file::tui_file): New method.
	(tui_file_fputs): Delete.
	(tui_file_get_strbuf): Delete.
	(tui_file::puts): New method.
	(tui_file_adjust_strbuf): Delete.
	(tui_file_flush): Delete.
	(tui_file::flush): New method.
	* tui/tui-file.h: Tweak intro comment.
	Include ui-file.h.
	(tui_fileopen, tui_sfileopen, tui_file_get_strbuf)
	(tui_file_adjust_strbuf): Delete declarations.
	(class tui_file): New class.
	* tui/tui-io.c (tui_initialize_io): Use tui_file.
	* tui/tui-regs.c (tui_restore_gdbout): Use delete.
	(tui_register_format): Use string_stream.
	* tui/tui-stack.c (tui_make_status_line): Use string_file.
	(tui_get_function_from_frame): Use string_file.
	* typeprint.c (type_to_string): Use string_file.
	* ui-file.c (struct ui_file, ui_file_magic, ui_file_new): Delete.
	(null_stream): New global.
	(ui_file_delete): Delete.
	(ui_file::ui_file): New.
	(null_file_isatty): Delete.
	(ui_file::~ui_file): New.
	(null_file_rewind): Delete.
	(ui_file::printf): New.
	(null_file_put): Delete.
	(null_file_flush): Delete.
	(ui_file::putstr): New.
	(null_file_write): Delete.
	(ui_file::putstrn): New.
	(null_file_read): Delete.
	(ui_file::putc): New.
	(null_file_fputs): Delete.
	(null_file_write_async_safe): Delete.
	(ui_file::vprintf): New.
	(null_file_delete): Delete.
	(null_file::write): New.
	(null_file_fseek): Delete.
	(null_file::puts): New.
	(ui_file_data): Delete.
	(null_file::write_async_safe): New.
	(gdb_flush, ui_file_isatty): Adjust.
	(ui_file_put, ui_file_rewind): Delete.
	(ui_file_write): Adjust.
	(ui_file_write_for_put): Delete.
	(ui_file_write_async_safe, ui_file_read): Adjust.
	(ui_file_fseek): Delete.
	(fputs_unfiltered): Adjust.
	(set_ui_file_flush, set_ui_file_isatty, set_ui_file_rewind)
	(set_ui_file_put, set_ui_file_write, set_ui_file_write_async_safe)
	(set_ui_file_read, set_ui_file_fputs, set_ui_file_fseek)
	(set_ui_file_data): Delete.
	(string_file::~string_file, string_file::write)
	(struct accumulated_ui_file, do_ui_file_xstrdup, ui_file_xstrdup)
	(do_ui_file_as_string, ui_file_as_string): Delete.
	(do_ui_file_obsavestring, ui_file_obsavestring): Delete.
	(struct mem_file): Delete.
	(mem_file_new): Delete.
	(stdio_file::stdio_file): New.
	(mem_file_delete): Delete.
	(stdio_file::stdio_file): New.
	(mem_fileopen): Delete.
	(stdio_file::~stdio_file): New.
	(mem_file_rewind): Delete.
	(stdio_file::set_stream): New.
	(mem_file_put): Delete.
	(stdio_file::open): New.
	(mem_file_write): Delete.
	(stdio_file_magic, struct stdio_file): Delete.
	(stdio_file_new, stdio_file_delete, stdio_file_flush): Delete.
	(stdio_file::flush): New.
	(stdio_file_read): Rename to ...
	(stdio_file::read): ... this.  Adjust.
	(stdio_file_write): Rename to ...
	(stdio_file::write): ... this.  Adjust.
	(stdio_file_write_async_safe): Rename to ...
	(stdio_file::write_async_safe) ... this.  Adjust.
	(stdio_file_fputs): Rename to ...
	(stdio_file::puts) ... this.  Adjust.
	(stdio_file_isatty): Delete.
	(stdio_file_fseek): Delete.
	(stdio_file::isatty): New.
	(stderr_file_write): Rename to ...
	(stderr_file::write) ... this.  Adjust.
	(stderr_file_fputs): Rename to ...
	(stderr_file::puts) ... this.  Adjust.
	(stderr_fileopen, stdio_fileopen, gdb_fopen): Delete.
	(stderr_file::stderr_file): New.
	(tee_file_magic): Delete.
	(struct tee_file): Delete.
	(tee_file::tee_file): New.
	(tee_file_new): Delete.
	(tee_file::~tee_file): New.
	(tee_file_delete): Delete.
	(tee_file_flush): Rename to ...
	(tee_file::flush): ... this.  Adjust.
	(tee_file_write): Rename to ...
	(tee_file::write): ... this.  Adjust.
	(tee_file::write_async_safe): New.
	(tee_file_fputs): Rename to ...
	(tee_file::puts): ... this.  Adjust.
	(tee_file_isatty): Rename to ...
	(tee_file::isatty): ... this.  Adjust.
	* ui-file.h (struct obstack, struct ui_file): Don't
	forward-declare.
	(ui_file_new, ui_file_flush_ftype, set_ui_file_flush)
	(ui_file_write_ftype)
	(set_ui_file_write, ui_file_fputs_ftype, set_ui_file_fputs)
	(ui_file_write_async_safe_ftype, set_ui_file_write_async_safe)
	(ui_file_read_ftype, set_ui_file_read, ui_file_isatty_ftype)
	(set_ui_file_isatty, ui_file_rewind_ftype, set_ui_file_rewind)
	(ui_file_put_method_ftype, ui_file_put_ftype, set_ui_file_put)
	(ui_file_delete_ftype, set_ui_file_data, ui_file_fseek_ftype)
	(set_ui_file_fseek): Delete.
	(ui_file_data, ui_file_delete, ui_file_rewind)
	(struct ui_file): New.
	(ui_file_up): New.
	(class null_file): New.
	(null_stream): Declare.
	(ui_file_write_for_put, ui_file_put): Delete.
	(ui_file_xstrdup, ui_file_as_string, ui_file_obsavestring):
	Delete.
	(ui_file_fseek, mem_fileopen, stdio_fileopen, stderr_fileopen)
	(gdb_fopen, tee_file_new): Delete.
	(struct string_file): New.
	(struct stdio_file): New.
	(stdio_file_up): New.
	(struct stderr_file): New.
	(class tee_file): New.
	* ui-out.c (ui_out::field_stream): Take a 'string_file &' instead
	of a 'ui_file *'.  Adjust.
	* ui-out.h (class ui_out) <field_stream>: Likewise.
	* utils.c (do_ui_file_delete, make_cleanup_ui_file_delete)
	(null_stream): Delete.
	(error_stream): Take a 'string_file &' instead of a 'ui_file *'.
	Adjust.
	* utils.h (struct ui_file): Delete forward declaration..
	(make_cleanup_ui_file_delete, null_stream): Delete declarations.
	(error_stream): Take a 'string_file &' instead of a
	'ui_file *'.
	* varobj.c (varobj_value_get_print_value): Use string_file.
	* xtensa-tdep.c (xtensa_verify_config): Use string_file.
	* gdbarch.c: Regenerate.

6 files changed, 61 insertions, 263 deletions

diff --git a/gdb/tui/tui-disasm.c b/gdb/tui/tui-disasm.c
index 2d1cadd9c6..123a9068f2 100644
--- a/gdb/tui/tui-disasm.c
+++ b/gdb/tui/tui-disasm.c
@@ -54,10 +54,7 @@ static CORE_ADDR
 tui_disassemble (struct gdbarch *gdbarch, struct tui_asm_line *asm_lines,
 		 CORE_ADDR pc, int count)
 {
-  struct ui_file *gdb_dis_out;
-
-  /* Now init the ui_file structure.  */
-  gdb_dis_out = tui_sfileopen (256);
+  string_file gdb_dis_out;
 
   /* Now construct each line.  */
   for (; count > 0; count--, asm_lines++)
@@ -67,20 +64,19 @@ tui_disassemble (struct gdbarch *gdbarch, struct tui_asm_line *asm_lines,
       if (asm_lines->insn)
         xfree (asm_lines->insn);
       
-      print_address (gdbarch, pc, gdb_dis_out);
+      print_address (gdbarch, pc, &gdb_dis_out);
       asm_lines->addr = pc;
-      asm_lines->addr_string = xstrdup (tui_file_get_strbuf (gdb_dis_out));
+      asm_lines->addr_string = xstrdup (gdb_dis_out.c_str ());
 
-      ui_file_rewind (gdb_dis_out);
+      gdb_dis_out.clear ();
 
-      pc = pc + gdb_print_insn (gdbarch, pc, gdb_dis_out, NULL);
+      pc = pc + gdb_print_insn (gdbarch, pc, &gdb_dis_out, NULL);
 
-      asm_lines->insn = xstrdup (tui_file_get_strbuf (gdb_dis_out));
+      asm_lines->insn = xstrdup (gdb_dis_out.c_str ());
 
       /* Reset the buffer to empty.  */
-      ui_file_rewind (gdb_dis_out);
+      gdb_dis_out.clear ();
     }
-  ui_file_delete (gdb_dis_out);
   return pc;
 }
 
diff --git a/gdb/tui/tui-file.c b/gdb/tui/tui-file.c
index 4dc6370d40..2f895b7a53 100644
--- a/gdb/tui/tui-file.c
+++ b/gdb/tui/tui-file.c
@@ -17,145 +17,14 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
-#include "ui-file.h"
 #include "tui/tui-file.h"
 #include "tui/tui-io.h"
 #include "tui/tui-command.h"
 #include "tui.h"
 
-/* A ``struct ui_file'' that is compatible with all the legacy
-   code.  */
-
-/* new */
-enum streamtype
-{
-  afile,
-  astring
-};
-
-/* new */
-struct tui_stream
-{
-  int *ts_magic;
-  enum streamtype ts_streamtype;
-  FILE *ts_filestream;
-  char *ts_strbuf;
-  int ts_buflen;
-};
-
-static ui_file_flush_ftype tui_file_flush;
-extern ui_file_fputs_ftype tui_file_fputs;
-static ui_file_isatty_ftype tui_file_isatty;
-static ui_file_rewind_ftype tui_file_rewind;
-static ui_file_put_ftype tui_file_put;
-static ui_file_delete_ftype tui_file_delete;
-static struct ui_file *tui_file_new (void);
-static int tui_file_magic;
-
-static struct ui_file *
-tui_file_new (void)
-{
-  struct tui_stream *tui = XNEW (struct tui_stream);
-  struct ui_file *file = ui_file_new ();
-
-  set_ui_file_data (file, tui, tui_file_delete);
-  set_ui_file_flush (file, tui_file_flush);
-  set_ui_file_fputs (file, tui_file_fputs);
-  set_ui_file_isatty (file, tui_file_isatty);
-  set_ui_file_rewind (file, tui_file_rewind);
-  set_ui_file_put (file, tui_file_put);
-  tui->ts_magic = &tui_file_magic;
-  return file;
-}
-
-static void
-tui_file_delete (struct ui_file *file)
-{
-  struct tui_stream *tmpstream = (struct tui_stream *) ui_file_data (file);
-
-  if (tmpstream->ts_magic != &tui_file_magic)
-    internal_error (__FILE__, __LINE__,
-		    _("tui_file_delete: bad magic number"));
-  if ((tmpstream->ts_streamtype == astring) 
-      && (tmpstream->ts_strbuf != NULL))
-    {
-      xfree (tmpstream->ts_strbuf);
-    }
-  xfree (tmpstream);
-}
-
-struct ui_file *
-tui_fileopen (FILE *stream)
-{
-  struct ui_file *file = tui_file_new ();
-  struct tui_stream *tmpstream = (struct tui_stream *) ui_file_data (file);
-
-  tmpstream->ts_streamtype = afile;
-  tmpstream->ts_filestream = stream;
-  tmpstream->ts_strbuf = NULL;
-  tmpstream->ts_buflen = 0;
-  return file;
-}
-
-struct ui_file *
-tui_sfileopen (int n)
-{
-  struct ui_file *file = tui_file_new ();
-  struct tui_stream *tmpstream = (struct tui_stream *) ui_file_data (file);
-
-  tmpstream->ts_streamtype = astring;
-  tmpstream->ts_filestream = NULL;
-  if (n > 0)
-    {
-      tmpstream->ts_strbuf = XNEWVEC (char, n + 1);
-      tmpstream->ts_strbuf[0] = '\0';
-    }
-  else
-    /* Do not allocate the buffer now.  The first time something is
-       printed one will be allocated by tui_file_adjust_strbuf().  */
-    tmpstream->ts_strbuf = NULL;
-  tmpstream->ts_buflen = n;
-  return file;
-}
-
-static int
-tui_file_isatty (struct ui_file *file)
-{
-  struct tui_stream *stream = (struct tui_stream *) ui_file_data (file);
-
-  if (stream->ts_magic != &tui_file_magic)
-    internal_error (__FILE__, __LINE__,
-		    _("tui_file_isatty: bad magic number"));
-  if (stream->ts_streamtype == afile)
-    return (isatty (fileno (stream->ts_filestream)));
-  else
-    return 0;
-}
-
-static void
-tui_file_rewind (struct ui_file *file)
-{
-  struct tui_stream *stream = (struct tui_stream *) ui_file_data (file);
-
-  if (stream->ts_magic != &tui_file_magic)
-    internal_error (__FILE__, __LINE__,
-		    _("tui_file_rewind: bad magic number"));
-  stream->ts_strbuf[0] = '\0';
-}
-
-static void
-tui_file_put (struct ui_file *file,
-	      ui_file_put_method_ftype *write,
-	      void *dest)
-{
-  struct tui_stream *stream = (struct tui_stream *) ui_file_data (file);
-
-  if (stream->ts_magic != &tui_file_magic)
-    internal_error (__FILE__, __LINE__,
-		    _("tui_file_put: bad magic number"));
-  if (stream->ts_streamtype == astring)
-    write (dest, stream->ts_strbuf, strlen (stream->ts_strbuf));
-}
+tui_file::tui_file (FILE *stream)
+  : stdio_file (stream)
+{}
 
 /* All TUI I/O sent to the *_filtered and *_unfiltered functions
    eventually ends up here.  The fputs_unfiltered_hook is primarily
@@ -164,91 +33,22 @@ tui_file_put (struct ui_file *file,
    gdb_stderr are sent to the hook.  Everything else is sent on to
    fputs to allow file I/O to be handled appropriately.  */
 
-/* FIXME: Should be broken up and moved to a TUI specific file.  */
-
 void
-tui_file_fputs (const char *linebuffer, struct ui_file *file)
-{
-  struct tui_stream *stream = (struct tui_stream *) ui_file_data (file);
-
-  if (stream->ts_streamtype == astring)
-    {
-      tui_file_adjust_strbuf (strlen (linebuffer), file);
-      strcat (stream->ts_strbuf, linebuffer);
-    }
-  else
-    {
-      tui_puts (linebuffer);
-      /* gdb_stdout is buffered, and the caller must gdb_flush it at
-	 appropriate times.  Other streams are not so buffered.  */
-      if (file != gdb_stdout)
-	tui_refresh_cmd_win ();
-    }
-}
-
-char *
-tui_file_get_strbuf (struct ui_file *file)
+tui_file::puts (const char *linebuffer)
 {
-  struct tui_stream *stream = (struct tui_stream *) ui_file_data (file);
-
-  if (stream->ts_magic != &tui_file_magic)
-    internal_error (__FILE__, __LINE__,
-		    _("tui_file_get_strbuf: bad magic number"));
-  return (stream->ts_strbuf);
+  tui_puts (linebuffer);
+  /* gdb_stdout is buffered, and the caller must gdb_flush it at
+     appropriate times.  Other streams are not so buffered.  */
+  if (this != gdb_stdout)
+    tui_refresh_cmd_win ();
 }
 
-/* Adjust the length of the buffer by the amount necessary to
-   accomodate appending a string of length N to the buffer
-   contents.  */
 void
-tui_file_adjust_strbuf (int n, struct ui_file *file)
-{
-  struct tui_stream *stream = (struct tui_stream *) ui_file_data (file);
-  int non_null_chars;
-
-  if (stream->ts_magic != &tui_file_magic)
-    internal_error (__FILE__, __LINE__,
-		    _("tui_file_adjust_strbuf: bad magic number"));
-
-  if (stream->ts_streamtype != astring)
-    return;
-
-  if (stream->ts_strbuf)
-    {
-      /* There is already a buffer allocated.  */
-      non_null_chars = strlen (stream->ts_strbuf);
-
-      if (n > (stream->ts_buflen - non_null_chars - 1))
-	{
-	  stream->ts_buflen = n + non_null_chars + 1;
-	  stream->ts_strbuf
-	    = XRESIZEVEC (char, stream->ts_strbuf, stream->ts_buflen);
-	}
-    }
-  else
-    /* No buffer yet, so allocate one of the desired size.  */
-    stream->ts_strbuf = XNEWVEC (char, n + 1);
-}
-
-static void
-tui_file_flush (struct ui_file *file)
+tui_file::flush ()
 {
-  struct tui_stream *stream = (struct tui_stream *) ui_file_data (file);
-
-  if (stream->ts_magic != &tui_file_magic)
-    internal_error (__FILE__, __LINE__,
-		    _("tui_file_flush: bad magic number"));
-
-  switch (stream->ts_streamtype)
-    {
-    case astring:
-      break;
-    case afile:
-      /* gdb_stdout is buffered.  Other files are always flushed on
-	 every write.  */
-      if (file == gdb_stdout)
-	tui_refresh_cmd_win ();
-      fflush (stream->ts_filestream);
-      break;
-    }
+  /* gdb_stdout is buffered.  Other files are always flushed on
+     every write.  */
+  if (this == gdb_stdout)
+    tui_refresh_cmd_win ();
+  stdio_file::flush ();
 }
diff --git a/gdb/tui/tui-file.h b/gdb/tui/tui-file.h
index 0e90cdf9b9..aceaab6bab 100644
--- a/gdb/tui/tui-file.h
+++ b/gdb/tui/tui-file.h
@@ -1,4 +1,4 @@
-/* UI_FILE - a generic STDIO like output stream.
+/* TUI_FILE - a STDIO-like output stream for the TUI.
    Copyright (C) 1999-2017 Free Software Foundation, Inc.
 
    This file is part of GDB.
@@ -19,9 +19,17 @@
 #ifndef TUI_FILE_H
 #define TUI_FILE_H
 
-extern struct ui_file *tui_fileopen (FILE *);
-extern struct ui_file *tui_sfileopen (int);
-extern char *tui_file_get_strbuf (struct ui_file *);
-extern void tui_file_adjust_strbuf (int, struct ui_file *);
+#include "ui-file.h"
+
+/* A STDIO-like output stream for the TUI.  */
+
+class tui_file : public stdio_file
+{
+public:
+  explicit tui_file (FILE *stream);
+
+  void flush () override;
+  void puts (const char *) override;
+};
 
 #endif
diff --git a/gdb/tui/tui-io.c b/gdb/tui/tui-io.c
index 6f00f84990..433762bc23 100644
--- a/gdb/tui/tui-io.c
+++ b/gdb/tui/tui-io.c
@@ -528,8 +528,8 @@ tui_initialize_io (void)
 #endif
 
   /* Create tui output streams.  */
-  tui_stdout = tui_fileopen (stdout);
-  tui_stderr = tui_fileopen (stderr);
+  tui_stdout = new tui_file (stdout);
+  tui_stderr = new tui_file (stderr);
   tui_out = tui_out_new (tui_stdout);
 
   /* Create the default UI.  */
diff --git a/gdb/tui/tui-regs.c b/gdb/tui/tui-regs.c
index fc7913b06c..7d116ee8d7 100644
--- a/gdb/tui/tui-regs.c
+++ b/gdb/tui/tui-regs.c
@@ -711,7 +711,7 @@ TUI command to control the register window."), tuicmd);
 static void
 tui_restore_gdbout (void *ui)
 {
-  ui_file_delete (gdb_stdout);
+  delete gdb_stdout;
   gdb_stdout = (struct ui_file*) ui;
   pagination_enabled = 1;
 }
@@ -723,29 +723,26 @@ static char *
 tui_register_format (struct frame_info *frame, int regnum)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct ui_file *stream;
   struct ui_file *old_stdout;
   struct cleanup *cleanups;
   char *p, *s;
   char *ret;
 
+  string_file stream;
+
   pagination_enabled = 0;
   old_stdout = gdb_stdout;
-  stream = tui_sfileopen (256);
-  gdb_stdout = stream;
+  gdb_stdout = &stream;
   cleanups = make_cleanup (tui_restore_gdbout, (void*) old_stdout);
-  gdbarch_print_registers_info (gdbarch, stream, frame, regnum, 1);
-
-  /* Save formatted output in the buffer.  */
-  p = tui_file_get_strbuf (stream);
+  gdbarch_print_registers_info (gdbarch, &stream, frame, regnum, 1);
 
   /* Remove the possible \n.  */
-  s = strrchr (p, '\n');
-  if (s && s[1] == 0)
-    *s = 0;
+  std::string &str = stream.string ();
+  if (!str.empty () && str.back () == '\n')
+    str.resize (str.size () - 1);
 
   /* Expand tabs into spaces, since ncurses on MS-Windows doesn't.  */
-  ret = tui_expand_tabs (p, 0);
+  ret = tui_expand_tabs (str.c_str (), 0);
 
   do_cleanups (cleanups);
 
diff --git a/gdb/tui/tui-stack.c b/gdb/tui/tui-stack.c
index 945a716462..21a8baceba 100644
--- a/gdb/tui/tui-stack.c
+++ b/gdb/tui/tui-stack.c
@@ -68,12 +68,9 @@ tui_make_status_line (struct tui_locator_element *loc)
   int status_size;
   int i, proc_width;
   const char *pid_name;
-  const char *pc_buf;
   int target_width;
   int pid_width;
   int line_width;
-  int pc_width;
-  struct ui_file *pc_out;
 
   if (ptid_equal (inferior_ptid, null_ptid))
     pid_name = "No process";
@@ -102,12 +99,14 @@ tui_make_status_line (struct tui_locator_element *loc)
     line_width = MIN_LINE_WIDTH;
 
   /* Translate PC address.  */
-  pc_out = tui_sfileopen (128);
+  string_file pc_out;
+
   fputs_filtered (loc->gdbarch? paddress (loc->gdbarch, loc->addr) : "??",
-		  pc_out);
-  pc_buf = tui_file_get_strbuf (pc_out);
-  pc_width = strlen (pc_buf);
-  
+		  &pc_out);
+
+  const char *pc_buf = pc_out.c_str ();
+  int pc_width = pc_out.size ();
+
   /* First determine the amount of proc name width we have available.
      The +1 are for a space separator between fields.
      The -1 are to take into account the \0 counted by sizeof.  */
@@ -204,7 +203,6 @@ tui_make_status_line (struct tui_locator_element *loc)
     string[i] = ' ';
   string[status_size] = (char) 0;
 
-  ui_file_delete (pc_out);
   return string;
 }
 
@@ -215,21 +213,21 @@ static char*
 tui_get_function_from_frame (struct frame_info *fi)
 {
   static char name[256];
-  struct ui_file *stream = tui_sfileopen (256);
-  char *p;
+  string_file stream;
 
   print_address_symbolic (get_frame_arch (fi), get_frame_pc (fi),
-			  stream, demangle, "");
-  p = tui_file_get_strbuf (stream);
+			  &stream, demangle, "");
 
   /* Use simple heuristics to isolate the function name.  The symbol
      can be demangled and we can have function parameters.  Remove
      them because the status line is too short to display them.  */
-  if (*p == '<')
-    p++;
-  strncpy (name, p, sizeof (name) - 1);
+  const char *d = stream.c_str ();
+  if (*d == '<')
+    d++;
+  strncpy (name, d, sizeof (name) - 1);
   name[sizeof (name) - 1] = 0;
-  p = strchr (name, '(');
+
+  char *p = strchr (name, '(');
   if (!p)
     p = strchr (name, '>');
   if (p)
@@ -237,7 +235,6 @@ tui_get_function_from_frame (struct frame_info *fi)
   p = strchr (name, '+');
   if (p)
     *p = 0;
-  ui_file_delete (stream);
   return name;
 }