gdb: move struct ui and related things to ui.{c,h}

I'd like to move some things so they become methods on struct ui.  But
first, I think that struct ui and the related things are big enough to
deserve their own file, instead of being scattered through top.{c,h} and
event-top.c.

Change-Id: I15594269ace61fd76ef80a7b58f51ff3ab6979bc

1 files changed, 251 insertions, 0 deletions

diff --git a/gdb/ui.c b/gdb/ui.c
new file mode 100644
index 0000000..5fe0012
--- /dev/null
+++ b/gdb/ui.c
@@ -0,0 +1,251 @@
+/* Copyright (C) 2023 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "ui.h"
+
+#include "cli/cli-cmds.h"
+#include "event-top.h"
+#include "gdbsupport/buildargv.h"
+#include "gdbsupport/filestuff.h"
+#include "gdbsupport/gdb_file.h"
+#include "gdbsupport/scoped_fd.h"
+#include "interps.h"
+#include "pager.h"
+#include "main.h"
+#include "top.h"
+
+/* See top.h.  */
+
+struct ui *main_ui;
+struct ui *current_ui;
+struct ui *ui_list;
+
+/* The highest UI number ever assigned.  */
+
+static int highest_ui_num;
+
+/* See top.h.  */
+
+ui::ui (FILE *instream_, FILE *outstream_, FILE *errstream_)
+  : num (++highest_ui_num),
+    stdin_stream (instream_),
+    instream (instream_),
+    outstream (outstream_),
+    errstream (errstream_),
+    input_fd (fileno (instream)),
+    m_input_interactive_p (ISATTY (instream)),
+    m_gdb_stdout (new pager_file (new stdio_file (outstream))),
+    m_gdb_stdin (new stdio_file (instream)),
+    m_gdb_stderr (new stderr_file (errstream)),
+    m_gdb_stdlog (new timestamped_file (m_gdb_stderr))
+{
+  unbuffer_stream (instream_);
+
+  if (ui_list == NULL)
+    ui_list = this;
+  else
+    {
+      struct ui *last;
+
+      for (last = ui_list; last->next != NULL; last = last->next)
+	;
+      last->next = this;
+    }
+}
+
+ui::~ui ()
+{
+  struct ui *ui, *uiprev;
+
+  uiprev = NULL;
+
+  for (ui = ui_list; ui != NULL; uiprev = ui, ui = ui->next)
+    if (ui == this)
+      break;
+
+  gdb_assert (ui != NULL);
+
+  if (uiprev != NULL)
+    uiprev->next = next;
+  else
+    ui_list = next;
+
+  delete m_gdb_stdin;
+  delete m_gdb_stdout;
+  delete m_gdb_stderr;
+}
+
+
+/* Returns whether GDB is running on an interactive terminal.  */
+
+bool
+ui::input_interactive_p () const
+{
+  if (batch_flag)
+    return false;
+
+  if (interactive_mode != AUTO_BOOLEAN_AUTO)
+    return interactive_mode == AUTO_BOOLEAN_TRUE;
+
+  return m_input_interactive_p;
+}
+
+
+/* When there is an event ready on the stdin file descriptor, instead
+   of calling readline directly throught the callback function, or
+   instead of calling gdb_readline_no_editing_callback, give gdb a
+   chance to detect errors and do something.  */
+
+static void
+stdin_event_handler (int error, gdb_client_data client_data)
+{
+  struct ui *ui = (struct ui *) client_data;
+
+  if (error)
+    {
+      /* Switch to the main UI, so diagnostics always go there.  */
+      current_ui = main_ui;
+
+      ui->unregister_file_handler ();
+      if (main_ui == ui)
+	{
+	  /* If stdin died, we may as well kill gdb.  */
+	  gdb_printf (gdb_stderr, _("error detected on stdin\n"));
+	  quit_command ((char *) 0, 0);
+	}
+      else
+	{
+	  /* Simply delete the UI.  */
+	  delete ui;
+	}
+    }
+  else
+    {
+      /* Switch to the UI whose input descriptor woke up the event
+	 loop.  */
+      current_ui = ui;
+
+      /* This makes sure a ^C immediately followed by further input is
+	 always processed in that order.  E.g,. with input like
+	 "^Cprint 1\n", the SIGINT handler runs, marks the async
+	 signal handler, and then select/poll may return with stdin
+	 ready, instead of -1/EINTR.  The
+	 gdb.base/double-prompt-target-event-error.exp test exercises
+	 this.  */
+      QUIT;
+
+      do
+	{
+	  call_stdin_event_handler_again_p = 0;
+	  ui->call_readline (client_data);
+	}
+      while (call_stdin_event_handler_again_p != 0);
+    }
+}
+
+/* See top.h.  */
+
+void
+ui::register_file_handler ()
+{
+  if (input_fd != -1)
+    add_file_handler (input_fd, stdin_event_handler, this,
+		      string_printf ("ui-%d", num), true);
+}
+
+/* See top.h.  */
+
+void
+ui::unregister_file_handler ()
+{
+  if (input_fd != -1)
+    delete_file_handler (input_fd);
+}
+
+/* Open file named NAME for read/write, making sure not to make it the
+   controlling terminal.  */
+
+static gdb_file_up
+open_terminal_stream (const char *name)
+{
+  scoped_fd fd = gdb_open_cloexec (name, O_RDWR | O_NOCTTY, 0);
+  if (fd.get () < 0)
+    perror_with_name  (_("opening terminal failed"));
+
+  return fd.to_file ("w+");
+}
+
+/* Implementation of the "new-ui" command.  */
+
+static void
+new_ui_command (const char *args, int from_tty)
+{
+  int argc;
+  const char *interpreter_name;
+  const char *tty_name;
+
+  dont_repeat ();
+
+  gdb_argv argv (args);
+  argc = argv.count ();
+
+  if (argc < 2)
+    error (_("Usage: new-ui INTERPRETER TTY"));
+
+  interpreter_name = argv[0];
+  tty_name = argv[1];
+
+  {
+    scoped_restore save_ui = make_scoped_restore (&current_ui);
+
+    /* Open specified terminal.  Note: we used to open it three times,
+       once for each of stdin/stdout/stderr, but that does not work
+       with Windows named pipes.  */
+    gdb_file_up stream = open_terminal_stream (tty_name);
+
+    std::unique_ptr<ui> ui
+      (new struct ui (stream.get (), stream.get (), stream.get ()));
+
+    ui->async = 1;
+
+    current_ui = ui.get ();
+
+    set_top_level_interpreter (interpreter_name);
+
+    interp_pre_command_loop (top_level_interpreter ());
+
+    /* Make sure the file is not closed.  */
+    stream.release ();
+
+    ui.release ();
+  }
+
+  gdb_printf ("New UI allocated\n");
+}
+
+void _initialize_ui ();
+void
+_initialize_ui ()
+{
+  cmd_list_element *c = add_cmd ("new-ui", class_support, new_ui_command, _("\
+Create a new UI.\n\
+Usage: new-ui INTERPRETER TTY\n\
+The first argument is the name of the interpreter to run.\n\
+The second argument is the terminal the UI runs on."), &cmdlist);
+  set_cmd_completer (c, interpreter_completer);
+}