/*******************************************************************************
 * libretroshare/src/util: smallobject.h                                       *
 *                                                                             *
 * libretroshare: retroshare core library                                      *
 *                                                                             *
 * Copyright (C) 2016 Gioacchino Mazzurco <gio@eigenlab.org>                   *
 * Copyright (C) 2008 Timo Bingmann http://idlebox.net/                        *
 *                                                                             *
 * This program is free software: you can redistribute it and/or modify        *
 * it under the terms of the GNU Lesser General Public License as              *
 * published by the Free Software Foundation, either version 3 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 Lesser General Public License for more details.                         *
 *                                                                             *
 * You should have received a copy of the GNU Lesser General Public License    *
 * along with this program. If not, see <https://www.gnu.org/licenses/>.       *
 *                                                                             *
 *******************************************************************************/
#ifndef _STACKTRACE_H_
#define _STACKTRACE_H_

#include <stdio.h>

#if defined(__linux__) && defined(__GLIBC__)

#include <stdlib.h>
#include <execinfo.h>
#include <cxxabi.h>

/** Print a demangled stack backtrace of the caller function to FILE* out. */
static inline void print_stacktrace(FILE *out = stderr, unsigned int max_frames = 63)
{
	fprintf(out, "stack trace:\n");

	// storage array for stack trace address data
	void* addrlist[max_frames+1];

	// retrieve current stack addresses
	int addrlen = backtrace(addrlist, sizeof(addrlist) / sizeof(void*));

	if (addrlen == 0)
	{
		fprintf(out, "  <empty, possibly corrupt>\n");
		return;
	}

	// resolve addresses into strings containing "filename(function+address)",
	// this array must be free()-ed
	char** symbollist = backtrace_symbols(addrlist, addrlen);

	// allocate string which will be filled with the demangled function name
	size_t funcnamesize = 256;
	char* funcname = (char*)malloc(funcnamesize);

	// iterate over the returned symbol lines. skip the first, it is the
	// address of this function.
	for (int i = 1; i < addrlen; i++)
	{
		char *begin_name = 0, *begin_offset = 0, *end_offset = 0;

		// find parentheses and +address offset surrounding the mangled name:
		// ./module(function+0x15c) [0x8048a6d]
		for (char *p = symbollist[i]; *p; ++p)
		{
			if (*p == '(') begin_name = p;
			else if (*p == '+') begin_offset = p;
			else if (*p == ')' && begin_offset)
			{
				end_offset = p;
				break;
			}
		}

		if (begin_name && begin_offset && end_offset && begin_name < begin_offset)
		{
			*begin_name++ = '\0';
			*begin_offset++ = '\0';
			*end_offset = '\0';

			// mangled name is now in [begin_name, begin_offset) and caller
			// offset in [begin_offset, end_offset). now apply
			// __cxa_demangle():

			int status;
			char* ret = abi::__cxa_demangle(begin_name, funcname, &funcnamesize, &status);
			if (status == 0)
			{
				funcname = ret; // use possibly realloc()-ed string
				fprintf(out, "  %s : %s+%s\n", symbollist[i], funcname, begin_offset);
			}
			else
			{
				// demangling failed. Output function name as a C function with
				// no arguments.
				fprintf(out, "  %s : %s()+%s\n", symbollist[i], begin_name, begin_offset);
			}
		}
		else
		{
			// couldn't parse the line? print the whole line.
			fprintf(out, "  %s\n", symbollist[i]);
		}
	}

	free(funcname);
	free(symbollist);
}

#else // defined(__linux__) && defined(__GLIBC__)
static inline void print_stacktrace(FILE *out = stderr, unsigned int max_frames = 63)
{
	(void) max_frames;

	fprintf(out, "TODO: 2016/01/01 print_stacktrace not implemented yet for WINDOWS_SYS and ANDROID\n");
}
#endif // defined(__linux__) && defined(__GLIBC__)

#endif // _STACKTRACE_H_