gdb/tui/tui-interp.c

   1 /* TUI Interpreter definitions for GDB, the GNU debugger.
   2
   3    Copyright (C) 2003, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "interps.h"
  22 #include "top.h"
  23 #include "event-top.h"
  24 #include "event-loop.h"
  25 #include "ui-out.h"
  26 #include "cli-out.h"
  27 #include "tui/tui-data.h"
  28 #include "readline/readline.h"
  29 #include "tui/tui-win.h"
  30 #include "tui/tui.h"
  31 #include "tui/tui-io.h"
  32 #include "exceptions.h"
  33
  34 /* Set to 1 when the TUI mode must be activated when we first start
  35    gdb.  */
  36 static int tui_start_enabled = 0;
  37
  38 /* Cleanup the tui before exiting.  */
  39
  40 static void
  41 tui_exit (void)
  42 {
  43   /* Disable the tui.  Curses mode is left leaving the screen in a
  44      clean state (see endwin()).  */
  45   tui_disable ();
  46 }
  47
  48 /* True if TUI is the top-level interpreter.  */
  49 static int tui_is_toplevel = 0;
  50
  51 /* These implement the TUI interpreter.  */
  52
  53 static void *
  54 tui_init (int top_level)
  55 {
  56   tui_is_toplevel = top_level;
  57
  58   /* Install exit handler to leave the screen in a good shape.  */
  59   atexit (tui_exit);
  60
  61   tui_initialize_static_data ();
  62
  63   tui_initialize_io ();
  64   tui_initialize_win ();
  65   if (ui_file_isatty (gdb_stdout))
  66     tui_initialize_readline ();
  67
  68   return NULL;
  69 }
  70
  71 /* True if enabling the TUI is allowed.  Example, if the top level
  72    interpreter is MI, enabling curses will certainly lose.  */
  73
  74 int
  75 tui_allowed_p (void)
  76 {
  77   /* Only if TUI is the top level interpreter.  Also don't try to
  78      setup curses (and print funny control characters) if we're not
  79      outputting to a terminal.  */
  80   return tui_is_toplevel && ui_file_isatty (gdb_stdout);
  81 }
  82
  83 static int
  84 tui_resume (void *data)
  85 {
  86   struct ui_file *stream;
  87
  88   /* gdb_setup_readline will change gdb_stdout.  If the TUI was
  89      previously writing to gdb_stdout, then set it to the new
  90      gdb_stdout afterwards.  */
  91
  92   stream = cli_out_set_stream (tui_old_uiout, gdb_stdout);
  93   if (stream != gdb_stdout)
  94     {
  95       cli_out_set_stream (tui_old_uiout, stream);
  96       stream = NULL;
  97     }
  98
  99   gdb_setup_readline ();
 100
 101   if (stream != NULL)
 102     cli_out_set_stream (tui_old_uiout, gdb_stdout);
 103
 104   if (tui_start_enabled)
 105     tui_enable ();
 106   return 1;
 107 }
 108
 109 static int
 110 tui_suspend (void *data)
 111 {
 112   tui_start_enabled = tui_active;
 113   tui_disable ();
 114   return 1;
 115 }
 116
 117 /* Display the prompt if we are silent.  */
 118
 119 static int
 120 tui_display_prompt_p (void *data)
 121 {
 122   if (interp_quiet_p (NULL))
 123     return 0;
 124   else
 125     return 1;
 126 }
 127
 128 static struct gdb_exception
 129 tui_exec (void *data, const char *command_str)
 130 {
 131   internal_error (__FILE__, __LINE__, _("tui_exec called"));
 132 }
 133
 134
 135 /* Initialize all the necessary variables, start the event loop,
 136    register readline, and stdin, start the loop.  */
 137
 138 static void
 139 tui_command_loop (void *data)
 140 {
 141   /* If we are using readline, set things up and display the first
 142      prompt, otherwise just print the prompt.  */
 143   if (async_command_editing_p)
 144     {
 145       int length;
 146       char *a_prompt;
 147       char *gdb_prompt = get_prompt ();
 148
 149       /* Tell readline what the prompt to display is and what function
 150          it will need to call after a whole line is read. This also
 151          displays the first prompt.  */
 152       length = strlen (PREFIX (0))
 153         + strlen (gdb_prompt) + strlen (SUFFIX (0)) + 1;
 154       a_prompt = (char *) alloca (length);
 155       strcpy (a_prompt, PREFIX (0));
 156       strcat (a_prompt, gdb_prompt);
 157       strcat (a_prompt, SUFFIX (0));
 158       rl_callback_handler_install (a_prompt, input_handler);
 159     }
 160   else
 161     display_gdb_prompt (0);
 162
 163   /* Loop until there is nothing to do. This is the entry point to the
 164      event loop engine. gdb_do_one_event, called via catch_errors()
 165      will process one event for each invocation.  It blocks waits for
 166      an event and then processes it.  >0 when an event is processed, 0
 167      when catch_errors() caught an error and <0 when there are no
 168      longer any event sources registered.  */
 169   while (1)
 170     {
 171       int result = catch_errors (gdb_do_one_event, 0, "", RETURN_MASK_ALL);
 172       if (result < 0)
 173         break;
 174
 175       /* Update gdb output according to TUI mode.  Since catch_errors
 176          preserves the uiout from changing, this must be done at top
 177          level of event loop.  */
 178       if (tui_active)
 179         uiout = tui_out;
 180       else
 181         uiout = tui_old_uiout;
 182
 183       if (result == 0)
 184         {
 185           /* If any exception escaped to here, we better enable
 186              stdin.  Otherwise, any command that calls async_disable_stdin,
 187              and then throws, will leave stdin inoperable.  */
 188           async_enable_stdin ();
 189           /* FIXME: this should really be a call to a hook that is
 190              interface specific, because interfaces can display the
 191              prompt in their own way.  */
 192           display_gdb_prompt (0);
 193           /* This call looks bizarre, but it is required.  If the user
 194              entered a command that caused an error,
 195              after_char_processing_hook won't be called from
 196              rl_callback_read_char_wrapper.  Using a cleanup there
 197              won't work, since we want this function to be called
 198              after a new prompt is printed.  */
 199           if (after_char_processing_hook)
 200             (*after_char_processing_hook) ();
 201           /* Maybe better to set a flag to be checked somewhere as to
 202              whether display the prompt or not.  */
 203         }
 204     }
 205
 206   /* We are done with the event loop. There are no more event sources
 207      to listen to.  So we exit GDB.  */
 208   return;
 209 }
 210
 211 /* Provide a prototype to silence -Wmissing-prototypes.  */
 212 extern initialize_file_ftype _initialize_tui_interp;
 213
 214 void
 215 _initialize_tui_interp (void)
 216 {
 217   static const struct interp_procs procs = {
 218     tui_init,
 219     tui_resume,
 220     tui_suspend,
 221     tui_exec,
 222     tui_display_prompt_p,
 223     tui_command_loop,
 224   };
 225
 226   /* Create a default uiout builder for the TUI.  */
 227   tui_out = tui_out_new (gdb_stdout);
 228   interp_add (interp_new (INTERP_TUI, NULL, tui_out, &procs));
 229   if (interpreter_p && strcmp (interpreter_p, INTERP_TUI) == 0)
 230     tui_start_enabled = 1;
 231
 232   if (interpreter_p && strcmp (interpreter_p, INTERP_CONSOLE) == 0)
 233     {
 234       xfree (interpreter_p);
 235       interpreter_p = xstrdup (INTERP_TUI);
 236     }
 237 }