contrib/gdb-6/gdb/exceptions.h

   1 /* Exception (throw catch) mechanism, for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
   4    1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
   5    Free Software Foundation, Inc.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #ifndef EXCEPTIONS_H
  23 #define EXCEPTIONS_H
  24
  25 #include "ui-out.h"
  26 #include <setjmp.h>
  27
  28 /* Reasons for calling throw_exceptions().  NOTE: all reason values
  29    must be less than zero.  enum value 0 is reserved for internal use
  30    as the return value from an initial setjmp().  The function
  31    catch_exceptions() reserves values >= 0 as legal results from its
  32    wrapped function.  */
  33
  34 enum return_reason
  35   {
  36     /* User interrupt.  */
  37     RETURN_QUIT = -2,
  38     /* Any other error.  */
  39     RETURN_ERROR
  40   };
  41
  42 #define RETURN_MASK(reason)     (1 << (int)(-reason))
  43 #define RETURN_MASK_QUIT        RETURN_MASK (RETURN_QUIT)
  44 #define RETURN_MASK_ERROR       RETURN_MASK (RETURN_ERROR)
  45 #define RETURN_MASK_ALL         (RETURN_MASK_QUIT | RETURN_MASK_ERROR)
  46 typedef int return_mask;
  47
  48 /* Describe all exceptions.  */
  49
  50 enum errors {
  51   GDB_NO_ERROR,
  52   /* Any generic error, the corresponding text is in
  53      exception.message.  */
  54   GENERIC_ERROR,
  55   NOT_FOUND_ERROR,
  56
  57   /* Thread library lacks support necessary for finding thread local
  58      storage.  */
  59   TLS_NO_LIBRARY_SUPPORT_ERROR,
  60
  61   /* Load module not found while attempting to find thread local storage.  */
  62   TLS_LOAD_MODULE_NOT_FOUND_ERROR,
  63
  64   /* Thread local storage has not been allocated yet.  */
  65   TLS_NOT_ALLOCATED_YET_ERROR,
  66
  67   /* Something else went wrong while attempting to find thread local
  68      storage.  The ``struct gdb_exception'' message field provides
  69      more detail.  */
  70   TLS_GENERIC_ERROR,
  71
  72   /* Problem parsing an XML document.  */
  73   XML_PARSE_ERROR,
  74
  75   /* Add more errors here.  */
  76   NR_ERRORS
  77 };
  78
  79 struct gdb_exception
  80 {
  81   enum return_reason reason;
  82   enum errors error;
  83   const char *message;
  84 };
  85
  86 /* A pre-defined non-exception.  */
  87 extern const struct gdb_exception exception_none;
  88
  89 /* Wrap set/long jmp so that it's more portable (internal to
  90    exceptions).  */
  91
  92 #if defined(HAVE_SIGSETJMP)
  93 #define EXCEPTIONS_SIGJMP_BUF           sigjmp_buf
  94 #define EXCEPTIONS_SIGSETJMP(buf)       sigsetjmp((buf), 1)
  95 #define EXCEPTIONS_SIGLONGJMP(buf,val)  siglongjmp((buf), (val))
  96 #else
  97 #define EXCEPTIONS_SIGJMP_BUF           jmp_buf
  98 #define EXCEPTIONS_SIGSETJMP(buf)       setjmp(buf)
  99 #define EXCEPTIONS_SIGLONGJMP(buf,val)  longjmp((buf), (val))
 100 #endif
 101
 102 /* Functions to drive the exceptions state m/c (internal to
 103    exceptions).  */
 104 EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (struct ui_out *func_uiout,
 105                                                  volatile struct gdb_exception *
 106                                                  exception,
 107                                                  return_mask mask);
 108 int exceptions_state_mc_action_iter (void);
 109 int exceptions_state_mc_action_iter_1 (void);
 110
 111 /* Macro to wrap up standard try/catch behavior.
 112
 113    The double loop lets us correctly handle code "break"ing out of the
 114    try catch block.  (It works as the "break" only exits the inner
 115    "while" loop, the outer for loop detects this handling it
 116    correctly.)  Of course "return" and "goto" are not so lucky.
 117
 118    For instance:
 119
 120    *INDENT-OFF*
 121
 122    volatile struct gdb_exception e;
 123    TRY_CATCH (e, RETURN_MASK_ERROR)
 124      {
 125      }
 126    switch (e.reason)
 127      {
 128      case RETURN_ERROR: ...
 129      }
 130
 131   */
 132
 133 #define TRY_CATCH(EXCEPTION,MASK) \
 134      { \
 135        EXCEPTIONS_SIGJMP_BUF *buf = \
 136          exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \
 137        EXCEPTIONS_SIGSETJMP (*buf); \
 138      } \
 139      while (exceptions_state_mc_action_iter ()) \
 140        while (exceptions_state_mc_action_iter_1 ())
 141
 142 /* *INDENT-ON* */
 143
 144
 145 /* If E is an exception, print it's error message on the specified
 146    stream. for _fprintf, prefix the message with PREFIX...  */
 147 extern void exception_print (struct ui_file *file, struct gdb_exception e);
 148 extern void exception_fprintf (struct ui_file *file, struct gdb_exception e,
 149                                const char *prefix,
 150                                ...) ATTR_FORMAT (printf, 3, 4);
 151
 152 /* Throw an exception (as described by "struct gdb_exception").  Will
 153    execute a LONG JUMP to the inner most containing exception handler
 154    established using catch_exceptions() (or similar).
 155
 156    Code normally throws an exception using error() et.al.  For various
 157    reaons, GDB also contains code that throws an exception directly.
 158    For instance, the remote*.c targets contain CNTRL-C signal handlers
 159    that propogate the QUIT event up the exception chain.  ``This could
 160    be a good thing or a dangerous thing.'' -- the Existential
 161    Wombat.  */
 162
 163 extern NORETURN void throw_exception (struct gdb_exception exception) ATTR_NORETURN;
 164 extern NORETURN void throw_verror (enum errors, const char *fmt, va_list ap)
 165      ATTR_NORETURN ATTR_FORMAT (printf, 2, 0);
 166 extern NORETURN void throw_vfatal (const char *fmt, va_list ap)
 167      ATTR_NORETURN ATTR_FORMAT (printf, 1, 0);
 168 extern NORETURN void throw_error (enum errors error, const char *fmt,
 169                                   ...) ATTR_NORETURN ATTR_FORMAT (printf, 2, 3);
 170
 171 /* Instead of deprecated_throw_reason, code should use catch_exception
 172    and throw_exception.  */
 173 extern NORETURN void deprecated_throw_reason (enum return_reason reason) ATTR_NORETURN;
 174
 175 /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
 176    handler.  If an exception (enum return_reason) is thrown using
 177    throw_exception() than all cleanups installed since
 178    catch_exceptions() was entered are invoked, the (-ve) exception
 179    value is then returned by catch_exceptions.  If FUNC() returns
 180    normally (with a postive or zero return value) then that value is
 181    returned by catch_exceptions().  It is an internal_error() for
 182    FUNC() to return a negative value.
 183
 184    For the period of the FUNC() call: UIOUT is installed as the output
 185    builder; ERRSTRING is installed as the error/quit message; and a
 186    new cleanup_chain is established.  The old values are restored
 187    before catch_exceptions() returns.
 188
 189    The variant catch_exceptions_with_msg() is the same as
 190    catch_exceptions() but adds the ability to return an allocated
 191    copy of the gdb error message.  This is used when a silent error is
 192    issued and the caller wants to manually issue the error message.
 193
 194    FIXME; cagney/2001-08-13: The need to override the global UIOUT
 195    builder variable should just go away.
 196
 197    This function superseeds catch_errors().
 198
 199    This function uses SETJMP() and LONGJUMP().  */
 200
 201 struct ui_out;
 202 typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args);
 203 extern int catch_exceptions (struct ui_out *uiout,
 204                              catch_exceptions_ftype *func, void *func_args,
 205                              return_mask mask);
 206 typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args);
 207 extern int catch_exceptions_with_msg (struct ui_out *uiout,
 208                                       catch_exceptions_ftype *func,
 209                                       void *func_args,
 210                                       char **gdberrmsg,
 211                                       return_mask mask);
 212
 213 /* This function, in addition, suppresses the printing of the captured
 214    error message.  It's up to the client to print it.  */
 215
 216 extern struct gdb_exception catch_exception (struct ui_out *uiout,
 217                                              catch_exception_ftype *func,
 218                                              void *func_args,
 219                                              return_mask mask);
 220
 221 /* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
 222    otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
 223    probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
 224    value. It's unfortunate that, catch_errors() does not return an
 225    indication of the exact exception that it caught - quit_flag might
 226    help.
 227
 228    This function is superseeded by catch_exceptions().  */
 229
 230 typedef int (catch_errors_ftype) (void *);
 231 extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask);
 232
 233 /* Template to catch_errors() that wraps calls to command
 234    functions. */
 235
 236 typedef void (catch_command_errors_ftype) (char *, int);
 237 extern int catch_command_errors (catch_command_errors_ftype *func, char *command, int from_tty, return_mask);
 238
 239 #endif