[deliverable/binutils-gdb.git] / gdb / exceptions.h

/* Exception (throw catch) mechanism, for GDB, the GNU debugger.

   Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
   1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 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 2 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, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#ifndef EXCEPTIONS_H
#define EXCEPTIONS_H

struct ui_out;

#include <setjmp.h>

/* Reasons for calling throw_exceptions().  NOTE: all reason values
   must be less than zero.  enum value 0 is reserved for internal use
   as the return value from an initial setjmp().  The function
   catch_exceptions() reserves values >= 0 as legal results from its
   wrapped function.  */

enum return_reason
  {
    /* User interrupt.  */
    RETURN_QUIT = -2,
    /* Any other error.  */
    RETURN_ERROR
  };

#define RETURN_MASK(reason)	(1 << (int)(-reason))
#define RETURN_MASK_QUIT	RETURN_MASK (RETURN_QUIT)
#define RETURN_MASK_ERROR	RETURN_MASK (RETURN_ERROR)
#define RETURN_MASK_ALL		(RETURN_MASK_QUIT | RETURN_MASK_ERROR)
typedef int return_mask;

/* Describe all exceptions.  */

enum errors {
  NO_ERROR,
  /* Any generic error, the corresponding text is in
     exception.message.  */
  GENERIC_ERROR,
  NOT_FOUND_ERROR,
  /* Add more errors here.  */
  NR_ERRORS
};

struct exception
{
  enum return_reason reason;
  enum errors error;
  const char *message;
};

/* A pre-defined non-exception.  */
extern const struct exception exception_none;

/* Wrap set/long jmp so that it's more portable (internal to
   exceptions).  */

#if defined(HAVE_SIGSETJMP)
#define EXCEPTIONS_SIGJMP_BUF		sigjmp_buf
#define EXCEPTIONS_SIGSETJMP(buf)	sigsetjmp((buf), 1)
#define EXCEPTIONS_SIGLONGJMP(buf,val)	siglongjmp((buf), (val))
#else
#define EXCEPTIONS_SIGJMP_BUF		jmp_buf
#define EXCEPTIONS_SIGSETJMP(buf)	setjmp(buf)
#define EXCEPTIONS_SIGLONGJMP(buf,val)	longjmp((buf), (val))
#endif

/* Functions to drive the exceptions state m/c (internal to
   exceptions).  */
EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (struct ui_out *func_uiout,
						 volatile struct exception *
						 exception,
						 return_mask mask);
int exceptions_state_mc_action_iter (void);
int exceptions_state_mc_action_iter_1 (void);

/* Macro to wrap up standard try/catch behavior.

   The double loop lets us correctly handle code "break"ing out of the
   try catch block.  (It works as the "break" only exits the inner
   "while" loop, the outer for loop detects this handling it
   correctly.)  Of course "return" and "goto" are not so lucky.

   For instance:

   *INDENT-OFF*

   volatile struct exception e;
   TRY_CATCH (e, RETURN_MASK_ERROR)
     {
     }
   switch (e.reason)
     {
     case RETURN_ERROR: ...
     }

  */

#define TRY_CATCH(EXCEPTION,MASK) \
     { \
       EXCEPTIONS_SIGJMP_BUF *buf = \
	 exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \
       EXCEPTIONS_SIGSETJMP (*buf); \
     } \
     while (exceptions_state_mc_action_iter ()) \
       while (exceptions_state_mc_action_iter_1 ())

/* *INDENT-ON* */


/* If E is an exception, print it's error message on the specified
   stream. for _fprintf, prefix the message with PREFIX...  */
extern void exception_print (struct ui_file *file, struct exception e);
extern void exception_fprintf (struct ui_file *file, struct exception e,
			       const char *prefix,
			       ...) ATTR_FORMAT (printf, 3, 4);

/* Throw an exception (as described by "struct exception").  Will
   execute a LONG JUMP to the inner most containing exception handler
   established using catch_exceptions() (or similar).

   Code normally throws an exception using error() et.al.  For various
   reaons, GDB also contains code that throws an exception directly.
   For instance, the remote*.c targets contain CNTRL-C signal handlers
   that propogate the QUIT event up the exception chain.  ``This could
   be a good thing or a dangerous thing.'' -- the Existential
   Wombat.  */

extern NORETURN void throw_exception (struct exception exception) ATTR_NORETURN;
extern NORETURN void throw_verror (enum errors, const char *fmt,
				   va_list ap) ATTR_NORETURN;
extern NORETURN void throw_vfatal (const char *fmt, va_list ap) ATTR_NORETURN;
extern NORETURN void throw_error (enum errors error, const char *fmt,
				  ...) ATTR_NORETURN ATTR_FORMAT (printf, 2, 3);

/* Instead of deprecated_throw_reason, code should use catch_exception
   and throw_exception.  */
extern NORETURN void deprecated_throw_reason (enum return_reason reason) ATTR_NORETURN;

/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
   handler.  If an exception (enum return_reason) is thrown using
   throw_exception() than all cleanups installed since
   catch_exceptions() was entered are invoked, the (-ve) exception
   value is then returned by catch_exceptions.  If FUNC() returns
   normally (with a postive or zero return value) then that value is
   returned by catch_exceptions().  It is an internal_error() for
   FUNC() to return a negative value.

   For the period of the FUNC() call: UIOUT is installed as the output
   builder; ERRSTRING is installed as the error/quit message; and a
   new cleanup_chain is established.  The old values are restored
   before catch_exceptions() returns.

   The variant catch_exceptions_with_msg() is the same as
   catch_exceptions() but adds the ability to return an allocated
   copy of the gdb error message.  This is used when a silent error is 
   issued and the caller wants to manually issue the error message.

   FIXME; cagney/2001-08-13: The need to override the global UIOUT
   builder variable should just go away.

   This function superseeds catch_errors().

   This function uses SETJMP() and LONGJUMP().  */

struct ui_out;
typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args);
extern int catch_exceptions (struct ui_out *uiout,
			     catch_exceptions_ftype *func, void *func_args,
			     return_mask mask);
typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args);
extern int catch_exceptions_with_msg (struct ui_out *uiout,
			     	      catch_exceptions_ftype *func, 
			     	      void *func_args,
			     	      char **gdberrmsg,
				      return_mask mask);

/* This function, in addition, suppresses the printing of the captured
   error message.  It's up to the client to print it.  */

extern struct exception catch_exception (struct ui_out *uiout,
					 catch_exception_ftype *func,
					 void *func_args,
					 return_mask mask);

/* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
   otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
   probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
   value. It's unfortunate that, catch_errors() does not return an
   indication of the exact exception that it caught - quit_flag might
   help.

   This function is superseeded by catch_exceptions().  */

typedef int (catch_errors_ftype) (void *);
extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask);

/* Template to catch_errors() that wraps calls to command
   functions. */

typedef void (catch_command_errors_ftype) (char *, int);
extern int catch_command_errors (catch_command_errors_ftype *func, char *command, int from_tty, return_mask);

#endif
Commit	Line	Data
60250e8b AC	1	/* Exception (throw catch) mechanism, for GDB, the GNU debugger.
	2
	3	Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
05ff989b AC	4	1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free
05ff989b AC	5	Software Foundation, Inc.
60250e8b AC	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 2 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, write to the Free Software
	21	Foundation, Inc., 59 Temple Place - Suite 330,
	22	Boston, MA 02111-1307, USA. */
	23
	24	#ifndef EXCEPTIONS_H
	25	#define EXCEPTIONS_H
	26
6941d02a AC	27	struct ui_out;
	28
	29	#include <setjmp.h>
	30
2a78bfb5	31	/* Reasons for calling throw_exceptions(). NOTE: all reason values
60250e8b AC	32	must be less than zero. enum value 0 is reserved for internal use
	33	as the return value from an initial setjmp(). The function
	34	catch_exceptions() reserves values >= 0 as legal results from its
	35	wrapped function. */
	36
	37	enum return_reason
	38	{
	39	/* User interrupt. */
	40	RETURN_QUIT = -2,
	41	/* Any other error. */
	42	RETURN_ERROR
	43	};
	44
	45	#define RETURN_MASK(reason) (1 << (int)(-reason))
	46	#define RETURN_MASK_QUIT RETURN_MASK (RETURN_QUIT)
	47	#define RETURN_MASK_ERROR RETURN_MASK (RETURN_ERROR)
	48	#define RETURN_MASK_ALL (RETURN_MASK_QUIT \| RETURN_MASK_ERROR)
	49	typedef int return_mask;
	50
2a78bfb5 AC	51	/* Describe all exceptions. */
	52
	53	enum errors {
	54	NO_ERROR,
	55	/* Any generic error, the corresponding text is in
	56	exception.message. */
	57	GENERIC_ERROR,
05ff989b	58	NOT_FOUND_ERROR,
2a78bfb5 AC	59	/* Add more errors here. */
	60	NR_ERRORS
	61	};
	62
	63	struct exception
	64	{
	65	enum return_reason reason;
	66	enum errors error;
b315da38	67	const char *message;
2a78bfb5 AC	68	};
2a78bfb5 AC	69
c1043fc2 AC	70	/* A pre-defined non-exception. */
	71	extern const struct exception exception_none;
	72
6941d02a AC	73	/* Wrap set/long jmp so that it's more portable (internal to
	74	exceptions). */
	75
	76	#if defined(HAVE_SIGSETJMP)
	77	#define EXCEPTIONS_SIGJMP_BUF sigjmp_buf
	78	#define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1)
	79	#define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val))
	80	#else
	81	#define EXCEPTIONS_SIGJMP_BUF jmp_buf
	82	#define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf)
	83	#define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val))
	84	#endif
	85
	86	/* Functions to drive the exceptions state m/c (internal to
	87	exceptions). */
	88	EXCEPTIONS_SIGJMP_BUF exceptions_state_mc_init (struct ui_out func_uiout,
	89	volatile struct exception *
	90	exception,
	91	return_mask mask);
	92	int exceptions_state_mc_action_iter (void);
	93	int exceptions_state_mc_action_iter_1 (void);
	94
	95	/* Macro to wrap up standard try/catch behavior.
	96
	97	The double loop lets us correctly handle code "break"ing out of the
	98	try catch block. (It works as the "break" only exits the inner
	99	"while" loop, the outer for loop detects this handling it
	100	correctly.) Of course "return" and "goto" are not so lucky.
	101
	102	For instance:
	103
	104	INDENT-OFF
	105
	106	volatile struct exception e;
	107	TRY_CATCH (e, RETURN_MASK_ERROR)
	108	{
	109	}
	110	switch (e.reason)
	111	{
	112	case RETURN_ERROR: ...
	113	}
	114
	115	*/
	116
	117	#define TRY_CATCH(EXCEPTION,MASK) \
8d19ca47 CV	118	{ \
	119	EXCEPTIONS_SIGJMP_BUF *buf = \
	120	exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \
	121	EXCEPTIONS_SIGSETJMP (*buf); \
	122	} \
	123	while (exceptions_state_mc_action_iter ()) \
	124	while (exceptions_state_mc_action_iter_1 ())
6941d02a AC	125
	126	/* INDENT-ON */
	127
	128
8a076db9	129	/* If E is an exception, print it's error message on the specified
9cbc821d AC	130	stream. for _fprintf, prefix the message with PREFIX... */
	131	extern void exception_print (struct ui_file *file, struct exception e);
	132	extern void exception_fprintf (struct ui_file *file, struct exception e,
	133	const char *prefix,
	134	...) ATTR_FORMAT (printf, 3, 4);
8a076db9	135
2a78bfb5 AC	136	/* Throw an exception (as described by "struct exception"). Will
	137	execute a LONG JUMP to the inner most containing exception handler
	138	established using catch_exceptions() (or similar).
60250e8b AC	139
	140	Code normally throws an exception using error() et.al. For various
	141	reaons, GDB also contains code that throws an exception directly.
	142	For instance, the remote*.c targets contain CNTRL-C signal handlers
	143	that propogate the QUIT event up the exception chain. ``This could
2a78bfb5 AC	144	be a good thing or a dangerous thing.'' -- the Existential
	145	Wombat. */
	146
	147	extern NORETURN void throw_exception (struct exception exception) ATTR_NORETURN;
6b1b7650 AC	148	extern NORETURN void throw_verror (enum errors, const char *fmt,
	149	va_list ap) ATTR_NORETURN;
	150	extern NORETURN void throw_vfatal (const char *fmt, va_list ap) ATTR_NORETURN;
05ff989b AC	151	extern NORETURN void throw_error (enum errors error, const char *fmt,
05ff989b AC	152	...) ATTR_NORETURN ATTR_FORMAT (printf, 2, 3);
60250e8b	153
315a522e AC	154	/* Instead of deprecated_throw_reason, code should use catch_exception
	155	and throw_exception. */
	156	extern NORETURN void deprecated_throw_reason (enum return_reason reason) ATTR_NORETURN;
	157
60250e8b AC	158	/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
	159	handler. If an exception (enum return_reason) is thrown using
	160	throw_exception() than all cleanups installed since
	161	catch_exceptions() was entered are invoked, the (-ve) exception
	162	value is then returned by catch_exceptions. If FUNC() returns
	163	normally (with a postive or zero return value) then that value is
	164	returned by catch_exceptions(). It is an internal_error() for
	165	FUNC() to return a negative value.
	166
	167	For the period of the FUNC() call: UIOUT is installed as the output
	168	builder; ERRSTRING is installed as the error/quit message; and a
	169	new cleanup_chain is established. The old values are restored
	170	before catch_exceptions() returns.
	171
	172	The variant catch_exceptions_with_msg() is the same as
	173	catch_exceptions() but adds the ability to return an allocated
	174	copy of the gdb error message. This is used when a silent error is
	175	issued and the caller wants to manually issue the error message.
	176
	177	FIXME; cagney/2001-08-13: The need to override the global UIOUT
	178	builder variable should just go away.
	179
	180	This function superseeds catch_errors().
	181
	182	This function uses SETJMP() and LONGJUMP(). */
	183
	184	struct ui_out;
	185	typedef int (catch_exceptions_ftype) (struct ui_out ui_out, void args);
	186	extern int catch_exceptions (struct ui_out *uiout,
	187	catch_exceptions_ftype func, void func_args,
1c3c7ee7	188	return_mask mask);
2a78bfb5	189	typedef void (catch_exception_ftype) (struct ui_out ui_out, void args);
60250e8b AC	190	extern int catch_exceptions_with_msg (struct ui_out *uiout,
	191	catch_exceptions_ftype *func,
	192	void *func_args,
1c3c7ee7	193	char **gdberrmsg,
60250e8b	194	return_mask mask);
8a076db9 AC	195
	196	/* This function, in addition, suppresses the printing of the captured
	197	error message. It's up to the client to print it. */
	198
2a78bfb5 AC	199	extern struct exception catch_exception (struct ui_out *uiout,
	200	catch_exception_ftype *func,
	201	void *func_args,
	202	return_mask mask);
60250e8b AC	203
	204	/* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
	205	otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
	206	probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
	207	value. It's unfortunate that, catch_errors() does not return an
	208	indication of the exact exception that it caught - quit_flag might
	209	help.
	210
	211	This function is superseeded by catch_exceptions(). */
	212
	213	typedef int (catch_errors_ftype) (void *);
	214	extern int catch_errors (catch_errors_ftype , void , char *, return_mask);
	215
	216	/* Template to catch_errors() that wraps calls to command
	217	functions. */
	218
	219	typedef void (catch_command_errors_ftype) (char *, int);
	220	extern int catch_command_errors (catch_command_errors_ftype func, char command, int from_tty, return_mask);
	221
	222	#endif