ObjFW  Artifact [ef6fdedc48]

Artifact ef6fdedc48e0233dfe2f0e549265b02d604584313ca4dce9d655e3123694fd10:

• File src/exceptions/OFException.m — part of check-in [3d16a30f41] at 2013-06-22 12:12:36 on branch trunk — Rework exceptions.

  This mostly removes the argument for the class in which the exception
  occurred. As backtraces were recently added for all platforms, the
  passed class does not give any extra information on where the exception
  occurred anymore.

  This also removes a few other arguments which were not too helpful. In
  the past, the idea was to pass as many arguments as possible so that it
  is easier to find the origin of the exception. However, as backtraces
  are a much better way to find the origin, those are not useful anymore
  and just make the exception more cumbersome to use. The rule is now to
  only pass arguments that might help in recovering from the exception or
  provide information that is otherwise not easily accessible. (user: js, size: 2520) [annotate] [blame] [check-ins using]

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013
 *   Jonathan Schleifer <js@webkeks.org>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#include "config.h"

#define _GNU_SOURCE

#include <stdlib.h>

#ifdef HAVE_DLFCN_H
# include <dlfcn.h>
#endif

#import "OFException.h"
#import "OFString.h"
#import "OFArray.h"

#import "autorelease.h"

struct _Unwind_Context;
typedef enum {
	_URC_OK		  = 0,
	_URC_END_OF_STACK = 5
}_Unwind_Reason_Code;

struct backtrace_ctx {
	void **backtrace;
	uint_fast8_t i;
};

extern _Unwind_Reason_Code _Unwind_Backtrace(
    _Unwind_Reason_Code(*)(struct _Unwind_Context*, void*), void*);
extern uintptr_t _Unwind_GetIP(struct _Unwind_Context*);

static _Unwind_Reason_Code
backtrace_callback(struct _Unwind_Context *ctx, void *data)
{
	struct backtrace_ctx *bt = data;

	if (bt->i < OF_BACKTRACE_SIZE) {
		bt->backtrace[bt->i++] = (void*)_Unwind_GetIP(ctx);
		return _URC_OK;
	}

	return _URC_END_OF_STACK;
}

@implementation OFException
+ (instancetype)exception
{
	return [[[self alloc] init] autorelease];
}

- init
{
	struct backtrace_ctx ctx;

	self = [super init];

	ctx.backtrace = _backtrace;
	ctx.i = 0;
	_Unwind_Backtrace(backtrace_callback, &ctx);

	return self;
}

- (OFString*)description
{
	return [OFString stringWithFormat:
	    @"An exception of type %@ occurred!", [self class]];
}

- (OFArray*)backtrace
{
	OFMutableArray *backtrace = [OFMutableArray array];
	void *pool = objc_autoreleasePoolPush();
	uint_fast8_t i;

	for (i = 0; i < OF_BACKTRACE_SIZE && _backtrace[i] != NULL; i++) {
#ifdef HAVE_DLFCN_H
		Dl_info info;

		if (dladdr(_backtrace[i], &info)) {
			ptrdiff_t offset = (char*)_backtrace[i] -
			    (char*)info.dli_saddr;

			if (info.dli_sname == NULL)
				info.dli_sname = "??";

			[backtrace addObject:
			    [OFString stringWithFormat: @"%p <%s+%td> at %s",
							_backtrace[i],
							info.dli_sname, offset,
							info.dli_fname]];
		} else
#endif
			[backtrace addObject:
			    [OFString stringWithFormat: @"%p", _backtrace[i]]];
	}

	objc_autoreleasePoolPop(pool);

	[backtrace makeImmutable];

	return backtrace;
}
@end