gdb/tui/tui-interp.c

   1 /* TUI Interpreter definitions for GDB, the GNU debugger.
   2
   3    Copyright (C) 2003, 2007, 2008, 2009, 2010, 2011
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "interps.h"
  23 #include "top.h"
  24 #include "event-top.h"
  25 #include "event-loop.h"
  26 #include "ui-out.h"
  27 #include "cli-out.h"
  28 #include "tui/tui-data.h"
  29 #include "readline/readline.h"
  30 #include "tui/tui-win.h"
  31 #include "tui/tui.h"
  32 #include "tui/tui-io.h"
  33 #include "exceptions.h"
  34
  35 /* Set to 1 when the TUI mode must be activated when we first start
  36    gdb.  */
  37 static int tui_start_enabled = 0;
  38
  39 /* Cleanup the tui before exiting.  */
  40
  41 static void
  42 tui_exit (void)
  43 {
  44   /* Disable the tui.  Curses mode is left leaving the screen in a
  45      clean state (see endwin()).  */
  46   tui_disable ();
  47 }
  48
  49 /* True if TUI is the top-level interpreter.  */
  50 static int tui_is_toplevel = 0;
  51
  52 /* These implement the TUI interpreter.  */
  53
  54 static void *
  55 tui_init (int top_level)
  56 {
  57   tui_is_toplevel = top_level;
  58
  59   /* Install exit handler to leave the screen in a good shape.  */
  60   atexit (tui_exit);
  61
  62   tui_initialize_static_data ();
  63
  64   tui_initialize_io ();
  65   tui_initialize_win ();
  66   if (ui_file_isatty (gdb_stdout))
  67     tui_initialize_readline ();
  68
  69   return NULL;
  70 }
  71
  72 /* True if enabling the TUI is allowed.  Example, if the top level
  73    interpreter is MI, enabling curses will certainly lose.  */
  74
  75 int
  76 tui_allowed_p (void)
  77 {
  78   /* Only if TUI is the top level interpreter.  Also don't try to
  79      setup curses (and print funny control characters) if we're not
  80      outputting to a terminal.  */
  81   return tui_is_toplevel && ui_file_isatty (gdb_stdout);
  82 }
  83
  84 static int
  85 tui_resume (void *data)
  86 {
  87   struct ui_file *stream;
  88
  89   /* gdb_setup_readline will change gdb_stdout.  If the TUI was
  90      previously writing to gdb_stdout, then set it to the new
  91      gdb_stdout afterwards.  */
  92
  93   stream = cli_out_set_stream (tui_old_uiout, gdb_stdout);
  94   if (stream != gdb_stdout)
  95     {
  96       cli_out_set_stream (tui_old_uiout, stream);
  97       stream = NULL;
  98     }
  99
 100   gdb_setup_readline ();
 101
 102   if (stream != NULL)
 103     cli_out_set_stream (tui_old_uiout, gdb_stdout);
 104
 105   if (tui_start_enabled)
 106     tui_enable ();
 107   return 1;
 108 }
 109
 110 static int
 111 tui_suspend (void *data)
 112 {
 113   tui_start_enabled = tui_active;
 114   tui_disable ();
 115   return 1;
 116 }
 117
 118 /* Display the prompt if we are silent.  */
 119
 120 static int
 121 tui_display_prompt_p (void *data)
 122 {
 123   if (interp_quiet_p (NULL))
 124     return 0;
 125   else
 126     return 1;
 127 }
 128
 129 static struct gdb_exception
 130 tui_exec (void *data, const char *command_str)
 131 {
 132   internal_error (__FILE__, __LINE__, _("tui_exec called"));
 133 }
 134
 135
 136 /* Initialize all the necessary variables, start the event loop,
 137    register readline, and stdin, start the loop.  */
 138
 139 static void
 140 tui_command_loop (void *data)
 141 {
 142   /* If we are using readline, set things up and display the first
 143      prompt, otherwise just print the prompt.  */
 144   if (async_command_editing_p)
 145     {
 146       int length;
 147       char *a_prompt;
 148       char *gdb_prompt = get_prompt (0);
 149
 150       /* Tell readline what the prompt to display is and what function
 151          it will need to call after a whole line is read. This also
 152          displays the first prompt.  */
 153       length = strlen (get_prefix (0))
 154         + strlen (gdb_prompt) + strlen (get_suffix (0)) + 1;
 155       a_prompt = (char *) alloca (length);
 156       strcpy (a_prompt, get_prefix (0));
 157       strcat (a_prompt, gdb_prompt);
 158       strcat (a_prompt, get_suffix (0));
 159       rl_callback_handler_install (a_prompt, input_handler);
 160     }
 161   else
 162     display_gdb_prompt (0);
 163
 164   /* Loop until there is nothing to do. This is the entry point to the
 165      event loop engine. gdb_do_one_event, called via catch_errors()
 166      will process one event for each invocation.  It blocks waits for
 167      an event and then processes it.  >0 when an event is processed, 0
 168      when catch_errors() caught an error and <0 when there are no
 169      longer any event sources registered.  */
 170   while (1)
 171     {
 172       int result = catch_errors (gdb_do_one_event, 0, "", RETURN_MASK_ALL);
 173
 174       if (result < 0)
 175         break;
 176
 177       /* Update gdb output according to TUI mode.  Since catch_errors
 178          preserves the uiout from changing, this must be done at top
 179          level of event loop.  */
 180       if (tui_active)
 181         current_uiout = tui_out;
 182       else
 183         current_uiout = tui_old_uiout;
 184
 185       if (result == 0)
 186         {
 187           /* If any exception escaped to here, we better enable
 188              stdin.  Otherwise, any command that calls async_disable_stdin,
 189              and then throws, will leave stdin inoperable.  */
 190           async_enable_stdin ();
 191           /* FIXME: this should really be a call to a hook that is
 192              interface specific, because interfaces can display the
 193              prompt in their own way.  */
 194           display_gdb_prompt (0);
 195           /* This call looks bizarre, but it is required.  If the user
 196              entered a command that caused an error,
 197              after_char_processing_hook won't be called from
 198              rl_callback_read_char_wrapper.  Using a cleanup there
 199              won't work, since we want this function to be called
 200              after a new prompt is printed.  */
 201           if (after_char_processing_hook)
 202             (*after_char_processing_hook) ();
 203           /* Maybe better to set a flag to be checked somewhere as to
 204              whether display the prompt or not.  */
 205         }
 206     }
 207
 208   /* We are done with the event loop. There are no more event sources
 209      to listen to.  So we exit GDB.  */
 210   return;
 211 }
 212
 213 /* Provide a prototype to silence -Wmissing-prototypes.  */
 214 extern initialize_file_ftype _initialize_tui_interp;
 215
 216 void
 217 _initialize_tui_interp (void)
 218 {
 219   static const struct interp_procs procs = {
 220     tui_init,
 221     tui_resume,
 222     tui_suspend,
 223     tui_exec,
 224     tui_display_prompt_p,
 225     tui_command_loop,
 226   };
 227
 228   /* Create a default uiout builder for the TUI.  */
 229   tui_out = tui_out_new (gdb_stdout);
 230   interp_add (interp_new (INTERP_TUI, NULL, tui_out, &procs));
 231   if (interpreter_p && strcmp (interpreter_p, INTERP_TUI) == 0)
 232     tui_start_enabled = 1;
 233
 234   if (interpreter_p && strcmp (interpreter_p, INTERP_CONSOLE) == 0)
 235     {
 236       xfree (interpreter_p);
 237       interpreter_p = xstrdup (INTERP_TUI);
 238     }
 239 }