#include "debughelper.h"
#include "mostQtHeaders.h"
#include "smallUsefulFunctions.h"
#include <stdio.h>
#include <stdlib.h>

//backtrace is only available on GNU libc
#ifndef __GLIBC__
#define NO_CRASH_HANDLER
#endif

#ifndef NO_CRASH_HANDLER
#if (defined(x86_64) || defined(__x86_64__))
#define CPU_IS_X86_64
#elif (defined(ppc) || defined(__ppc__) || defined(__powerpc__) || defined(__POWERPC__) || defined(PPC) || defined(__PPC) || defined(_ARCH_PPC))
#define CPU_IS_PPC
#elif (defined(ppc64) || defined(__ppc64__) || defined(__powerpc64__) || defined(__POWERPC64__) || defined(PPC64))
#define CPU_IS_PPC
#elif (defined(arm) || defined(__arm__))
#define CPU_IS_ARM
#elif (defined(ia64) || defined(__ia64__))
#define CPU_IS_IA64
#elif (defined(mips) || defined(__mips__) || defined(mipsel) || defined(__mipsel__))
#define CPU_IS_MIPS
#elif (defined(sparc) || defined(__sparc__))
#define CPU_IS_SPARC32
#elif (defined(s390x) || defined(__s390x__))
#define CPU_IS_S390_64
#elif (defined(s390) || defined(__s390__) )
#define CPU_IS_S390_31
#else
#define CPU_IS_X86_32
#endif


#if (defined(__unix__) || defined(unix) || defined(__linux__) || defined(linux) || defined(__gnu_hurd__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__))
#define OS_IS_LINUX_LIKE
#endif

#if (defined(OS_IS_LINUX_LIKE) || defined(Q_OS_MAC))
#define OS_IS_UNIX_LIKE
#endif

//===========================Abstract CPU model==========================

//platfom independent implementation of assembler instructions
//(use case: before changing eip, the old eip must be pushed in the correct way on the stack, otherwise the
//           backtrace doesn't show the function that actually crashed)
struct SimulatedCPU {
	char *pc;  //e.g. eip, r15
	char *frame;  //e.g. ebp, r11
	char *stack;  //e.g. esp, r13
#if defined(CPU_IS_ARM) || defined(CPU_IS_MIPS) || defined(CPU_IS_PPC) || defined(CPU_IS_SPARC32)
	char *returnTo;  //lr/r14
#endif

	inline void push(char *value)
	{
		stack -= sizeof(void *);
		*(char **)(stack) = value;
	}
	
	inline char *pop()
	{
		char *temp = *(char **)(stack);
		stack += sizeof(void *);
		return temp;
	}

	inline void jmp(char *value)
	{
		pc = value;
	}

	inline void call(char *value);
	inline void ret();
	inline void enter(int size);
	inline void leave();


	void set_all(void *context);
	void get_all(void *context);
	void set_from_real();

	bool stackWalk();
	void unwindStack()
	{
		SimulatedCPU temp = *this;
		int frames = 0;
		while (temp.stackWalk()) frames++;
		if (frames == 0) return;
		if (frames < 100) frames = frames - 10;
		else frames = frames - 100;
		while (frames > 0) {
			this->leave();
			frames--;
		}
	}

	int backtrace(void **array, int size)
	{
		if (!pc || !frame) return 0;
		for (int i = 0; i < size; i++)
			array[i] = 0;
		int i = 0;
		do {
			array[i] = pc;
			i++;
		} while (stackWalk() && i < size);
		return i;
	}
};

#ifdef CPU_CONTEXT_TYPE
#undef CPU_CONTEXT_TYPE
#endif
#ifdef RETURNTO_FROM_UCONTEXT
#undef RETURNTO_FROM_UCONTEXT
#endif


//===========================CRASH HANDLER HEADER==============================

#ifdef OS_IS_UNIX_LIKE
#include "signal.h"
#include "unistd.h"
#include "sys/wait.h"
#define SAFE_INT volatile sig_atomic_t
#else
#define SAFE_INT int
#endif

SAFE_INT crashHandlerType = 1;
enum { ERR_NONE = 0, ERR_SIGNAL, ERR_ASSERT, ERR_LOOP, ERR_EXCEPTION};
SAFE_INT lastErrorType = 0;
volatile void *sigSegvRecoverReturnAddress = 0; //address where it should jump to, if recovering causes another sigsegv

#define CRASH_HANDLER_RECOVER 1
#define CRASH_HANDLER_PRINT_BACKTRACE_IN_HANDLER 2
#define CRASH_HANDLER_LOOP_GUARDIAN_DISABLED 4
#define CRASH_HANDLER_USE_NATIVE_BACKTRACE 8


//===========================STACK TRACE PRINTING=========================

#ifdef Q_OS_WIN32
#include <QSysInfo>
#include "windows.h"
#include <QMutex>

//from wine
//dbghelp.h
typedef BOOL WINAPI (*SymInitializeFunc)(HANDLE, PCSTR, BOOL);

typedef PVOID WINAPI (*SymFunctionTableAccess64Func)(HANDLE, DWORD64);
typedef DWORD64 WINAPI (*SymGetModuleBase64Func)(HANDLE, DWORD64);
typedef enum {
	AddrMode1616,
	AddrMode1632,
	AddrModeReal,
	AddrModeFlat
} ADDRESS_MODE;
//
// New KDHELP structure for 64 bit system support.
// This structure is preferred in new code.
//
typedef struct _KDHELP64 {

	//
	// address of kernel thread object, as provided in the
	// WAIT_STATE_CHANGE packet.
	//
	DWORD64   Thread;

	//
	// offset in thread object to pointer to the current callback frame
	// in kernel stack.
	//
	DWORD   ThCallbackStack;

	//
	// offset in thread object to pointer to the current callback backing
	// store frame in kernel stack.
	//
	DWORD   ThCallbackBStore;

	//
	// offsets to values in frame:
	//
	// address of next callback frame
	DWORD   NextCallback;

	// address of saved frame pointer (if applicable)
	DWORD   FramePointer;


	//
	// Address of the kernel function that calls out to user mode
	//
	DWORD64   KiCallUserMode;

	//
	// Address of the user mode dispatcher function
	//
	DWORD64   KeUserCallbackDispatcher;

	//
	// Lowest kernel mode address
	//
	DWORD64   SystemRangeStart;

	DWORD64  Reserved[8];

} KDHELP64, *PKDHELP64;

typedef struct _tagADDRESS64 {
	DWORD64       Offset;
	WORD          Segment;
	ADDRESS_MODE  Mode;
} ADDRESS64, *LPADDRESS64;

typedef struct _STACKFRAME64 {
	ADDRESS64   AddrPC;
	ADDRESS64   AddrReturn;
	ADDRESS64   AddrFrame;
	ADDRESS64   AddrStack;
	ADDRESS64   AddrBStore;
	PVOID       FuncTableEntry;
	DWORD64     Params[4];
	BOOL        Far;
	BOOL        Virtual;
	DWORD64     Reserved[3];
	KDHELP64    KdHelp;
} STACKFRAME64, *LPSTACKFRAME64;

typedef BOOL (CALLBACK *PREAD_PROCESS_MEMORY_ROUTINE64)(HANDLE, DWORD64, PVOID, DWORD, PDWORD);
typedef PVOID (CALLBACK *PFUNCTION_TABLE_ACCESS_ROUTINE64)(HANDLE, DWORD64);
typedef DWORD64 (CALLBACK *PGET_MODULE_BASE_ROUTINE64)(HANDLE, DWORD64);
typedef DWORD64 (CALLBACK *PTRANSLATE_ADDRESS_ROUTINE64)(HANDLE, HANDLE, LPADDRESS64);
typedef BOOL WINAPI (*StackWalk64Func)(DWORD, HANDLE, HANDLE, LPSTACKFRAME64, PVOID,
                                       PREAD_PROCESS_MEMORY_ROUTINE64,
                                       PFUNCTION_TABLE_ACCESS_ROUTINE64,
                                       PGET_MODULE_BASE_ROUTINE64,
                                       PTRANSLATE_ADDRESS_ROUTINE64);

typedef struct _IMAGEHLP_SYMBOL64 {
	DWORD                       SizeOfStruct;
	DWORD64                     Address;
	DWORD                       Size;
	DWORD                       Flags;
	DWORD                       MaxNameLength;
	CHAR                        Name[1];
} IMAGEHLP_SYMBOL64, *PIMAGEHLP_SYMBOL64;

typedef struct _IMAGEHLP_LINE64 {
	DWORD                       SizeOfStruct;
	PVOID                       Key;
	DWORD                       LineNumber;
	PCHAR                       FileName;
	DWORD64                     Address;
} IMAGEHLP_LINE64, *PIMAGEHLP_LINE64;

typedef BOOL WINAPI (*SymGetSymFromAddr64Func)(HANDLE, DWORD64, PDWORD64, PIMAGEHLP_SYMBOL64);
typedef BOOL WINAPI (*SymGetLineFromAddr64Func)(HANDLE, DWORD64, PDWORD, PIMAGEHLP_LINE64);

#define CPU_CONTEXT_TYPE CONTEXT
#define LOAD_FUNCTION(name, ansiname) static name##Func name = (name##Func)GetProcAddress(dbghelp, ansiname);
#define LOAD_FUNCTIONREQRET(name, ansiname, result) LOAD_FUNCTION(name,ansiname) if (!name) return result;

HMODULE dbghelp = 0;

bool loadDbgHelp()
{
	if (dbghelp != 0) return true;
	dbghelp = LoadLibraryA("dbghelp.dll");
	return dbghelp;
}

bool initDebugHelp()
{
	if (dbghelp != 0) return true; //don't call syminitialize twice
	if (!loadDbgHelp()) return false;

	LOAD_FUNCTIONREQRET(SymInitialize, "SymInitialize", false);

	if (!(*SymInitialize)(((QSysInfo::windowsVersion() & QSysInfo::WV_DOS_based) == 0) ? GetCurrentProcess() : (HANDLE)GetCurrentProcessId(), 0, true))
		return false;
	return true;
}

QStringList backtrace_symbols_win(void **addr, int size)
{
	if (!initDebugHelp()) {
		if (dbghelp) return QStringList(QString("Failed to initialize SymInitialize ") + QString::number(GetLastError()));
		else return QStringList("Failed to load dbghelp");
	}

	LOAD_FUNCTIONREQRET(SymGetSymFromAddr64, "SymGetSymFromAddr64", QStringList("Failed to load SymGetSymFromAddr64"));
	LOAD_FUNCTION(SymGetLineFromAddr64, "SymGetLineFromAddr64");

	HANDLE process = GetCurrentProcess();

	_IMAGEHLP_SYMBOL64 *symbol = (_IMAGEHLP_SYMBOL64 *)malloc(sizeof(_IMAGEHLP_SYMBOL64) + 256);
	QStringList res;
	for (int i = 0; i < size; i++) {
		DWORD64 displacement = 0;
		DWORD displacement32 = 0;
		ZeroMemory(symbol, sizeof(_IMAGEHLP_SYMBOL64));
		symbol->SizeOfStruct = sizeof(_IMAGEHLP_SYMBOL64);
		symbol->MaxNameLength = 256;

		_IMAGEHLP_LINE64 line;

		QString cur;

		if ((*SymGetSymFromAddr64)(process, (DWORD64)addr[i], &displacement, symbol))
			cur = QString::fromLocal8Bit(symbol->Name) + "+" + QString::number(displacement);
		else
			cur = "??? error: " + QString::number(GetLastError());


		if (SymGetLineFromAddr64) {
			if ((*SymGetLineFromAddr64)(process, (DWORD64)addr[i], &displacement32, &line))
				cur += " in " + QString::fromLocal8Bit(line.FileName) + ":" + QString::number(line.LineNumber);
		}

		res << cur;
	}
	return res;
}

QMutex backtraceMutex;

//from http://jpassing.com/2008/03/12/walking-the-stack-of-the-current-thread/
//     http://www.codeproject.com/Articles/11132/Walking-the-callstack
//alternative: __builtin_return_address, but it is said to not work so well
int backtrace(void **trace, int size)
{
	if (!backtraceMutex.tryLock()) return 0;

	//init crap
	HANDLE process =  GetCurrentProcess();
	HANDLE thread = GetCurrentThread();

	if (!initDebugHelp()) return 0; //do not unlock, no need to try it again, if the initialization fails

	CONTEXT context;
	ZeroMemory( &context, sizeof( CONTEXT ) );
	STACKFRAME64 stackFrame;
#if (defined(x86_64) || defined(__x86_64__))
	RtlCaptureContext( &context );
#else
	// Those three registers are enough.
geteip:
	context.Eip = (DWORD) && geteip;
	__asm__(
	    "mov %%ebp, %0\n"
	    "mov %%esp, %1"
	    : "=r"(context.Ebp), "=r"(context.Esp));
#endif
	ZeroMemory( &stackFrame, sizeof( stackFrame ) );
#ifdef CPU_IS_64
	DWORD machineType           = IMAGE_FILE_MACHINE_AMD64;
	stackFrame.AddrPC.Offset    = context.Rip;
	stackFrame.AddrPC.Mode      = AddrModeFlat;
	stackFrame.AddrFrame.Offset = context.Rbp;//changed from rsp. correctly?
	stackFrame.AddrFrame.Mode   = AddrModeFlat;
	stackFrame.AddrStack.Offset = context.Rsp;
	stackFrame.AddrStack.Mode   = AddrModeFlat;
#else
	DWORD machineType           = IMAGE_FILE_MACHINE_I386;
	stackFrame.AddrPC.Offset    = context.Eip;
	stackFrame.AddrPC.Mode      = AddrModeFlat;
	stackFrame.AddrFrame.Offset = context.Ebp;
	stackFrame.AddrFrame.Mode   = AddrModeFlat;
	stackFrame.AddrStack.Offset = context.Esp;
	stackFrame.AddrStack.Mode   = AddrModeFlat;
	/* #elif _M_IA64
	MachineType                 = IMAGE_FILE_MACHINE_IA64;
	StackFrame.AddrPC.Offset    = Context.StIIP;
	StackFrame.AddrPC.Mode      = AddrModeFlat;
	StackFrame.AddrFrame.Offset = Context.IntSp;
	StackFrame.AddrFrame.Mode   = AddrModeFlat;
	StackFrame.AddrBStore.Offset= Context.RsBSP;
	StackFrame.AddrBStore.Mode  = AddrModeFlat;
	StackFrame.AddrStack.Offset = Context.IntSp;
	StackFrame.AddrStack.Mode   = AddrModeFlat;
#else
#error "Unsupported platform"*/
#endif

	static HMODULE dbghelp = LoadLibraryA("dbghelp.dll");
	if (!dbghelp) return 0;

	LOAD_FUNCTIONREQRET(StackWalk64, "StackWalk64", 0);
	LOAD_FUNCTIONREQRET(SymGetModuleBase64, "SymGetModuleBase64", 0);
	LOAD_FUNCTIONREQRET(SymFunctionTableAccess64, "SymFunctionTableAccess64", 0);

	//get stackframes
	QList<DWORD64> stackFrames;
	int idx = 0;
	while (idx < size && (*StackWalk64)(machineType, process, thread, &stackFrame, &context, 0, SymFunctionTableAccess64, SymGetModuleBase64, 0)) {
		trace[idx] = reinterpret_cast<void *>(stackFrame.AddrPC.Offset);
		idx++;
	}

	backtraceMutex.unlock();

	return idx;
}

QString temporaryFileNameFormat()
{
	return QDir::tempPath() + QString("/texstudio_backtrace%1.txt");
}

#elif defined(__GLIBC__)
#include "execinfo.h"
QString temporaryFileNameFormat()
{
	return "/tmp/texstudio_backtrace%1.txt";
}
QStringList backtrace_symbols_win(void **, int)
{
	return QStringList();
}

#endif



QString print_backtrace(const SimulatedCPU &state, const QString &message)
{
#ifdef Q_OS_WIN32
	qDebug("%s", qPrintable(message));
#define PRINT(...) do { qDebug(__VA_ARGS__); if (logFile) fprintf(logFile, __VA_ARGS__);  } while (0)
#else
	fprintf(stderr, "%s\n", qPrintable(message));
	qDebug("%s", qPrintable(message));
#define PRINT(...) do { fprintf(stderr, __VA_ARGS__); qDebug(__VA_ARGS__); if (logFile) fprintf(logFile, __VA_ARGS__); } while (0)
#endif
	static int count = 0;
	count++;
	QString backtraceFilename = temporaryFileNameFormat().arg(count);
	FILE *logFile = fopen(qPrintable(backtraceFilename), "w");
	PRINT("%s\n", qPrintable(message));

	void *trace[48];
	SimulatedCPU copystate = state;
	int size;

#if defined(CPU_IS_MIPS) || defined(CPU_IS_IA64) || defined(CPU_IS_SPARC32) || defined(CPU_IS_S390_31) || defined(CPU_IS_390_64)
	bool useNativeBacktrace = true //always use standard backtrace on exotic architectures
#else
	bool useNativeBacktrace = (crashHandlerType & CRASH_HANDLER_USE_NATIVE_BACKTRACE);
#endif
	                          if (useNativeBacktrace) size = backtrace(trace, 48);
	else size = copystate.backtrace(trace, 48);

#ifdef Q_OS_WIN32
	QStringList additionalMessages = backtrace_symbols_win(trace, size);
	char **messages = 0;
#else
	QStringList additionalMessages;
	char **messages = backtrace_symbols(trace, size);
#endif
	for (int i = 0; i < size; ++i) {
		const char *message = messages ? messages[i] : "";
		if (i >= additionalMessages.size()) PRINT("[bt] %s\n", message);
		else PRINT("[bt] %p %s %s\n", trace[i], message, qPrintable(additionalMessages[i]));
	}

	if (logFile) fclose(logFile);
	return backtraceFilename;
}

QString print_backtrace(const QString &message)
{
	SimulatedCPU cpu;
	cpu.set_from_real();
	return print_backtrace(cpu, message);
}


//=========================POSIX SIGNAL HANDLER===========================

#ifdef OS_IS_LINUX_LIKE
#include "signal.h"
#include "ucontext.h"
#include "sys/ucontext.h"
#include "pthread.h"

#define USE_SIGNAL_HANDLER
#ifdef CPU_IS_X86_64
#if defined(__FreeBSD__)
#define PC_FROM_UCONTEXT(context) (context)->uc_mcontext.mc_rip
#define STACK_FROM_UCONTEXT(context) (context)->uc_mcontext.mc_rsp
#define FRAME_FROM_UCONTEXT(context) (context)->uc_mcontext.mc_rbp
#else
#define PC_FROM_UCONTEXT(context) (context)->uc_mcontext.gregs[REG_RIP]
#define STACK_FROM_UCONTEXT(context) (context)->uc_mcontext.gregs[REG_RSP]
#define FRAME_FROM_UCONTEXT(context) (context)->uc_mcontext.gregs[REG_RBP]
#endif
#elif defined(CPU_IS_X86_32)
#if defined(__FreeBSD__)
#define PC_FROM_UCONTEXT(context) (context)->uc_mcontext.mc_eip
#define STACK_FROM_UCONTEXT(context) (context)->uc_mcontext.mc_esp
#define FRAME_FROM_UCONTEXT(context) (context)->uc_mcontext.mc_ebp
#else
#define PC_FROM_UCONTEXT(context) (context)->uc_mcontext.gregs[REG_EIP]
#define STACK_FROM_UCONTEXT(context) (context)->uc_mcontext.gregs[REG_ESP]
#define FRAME_FROM_UCONTEXT(context) (context)->uc_mcontext.gregs[REG_EBP]
#endif
#elif defined(CPU_IS_PPC)
#define PC_FROM_UCONTEXT(context) (context)->uc_mcontext.gp_regs[32]
#define STACK_FROM_UCONTEXT(context) (context)->uc_mcontext.gp_regs[1]
#define FRAME_FROM_UCONTEXT(context) (context)->uc_mcontext.gp_regs[31] //not always used
#define RETURNTO_FROM_UCONTEXT(context) (context)->uc_mcontext.gp_regs[34]
#elif defined(CPU_IS_ARM)
/*
#define PC_FROM_UCONTEXT(context) (context)->uc_mcontext.arm_pc
#define STACK_FROM_UCONTEXT(context) (context)->uc_mcontext.arm_sp
#define FRAME_FROM_UCONTEXT(context) (context)->uc_mcontext.arm_fp
#define RETURNTO_FROM_UCONTEXT(context) (context)->uc_mcontext.arm_lr
*/
#define PC_FROM_UCONTEXT(context) (context)->uc_mcontext.__gregs[_REG_R15]
#define STACK_FROM_UCONTEXT(context) (context)->uc_mcontext.__gregs[_REG_R13]
#define FRAME_FROM_UCONTEXT(context) (context)->uc_mcontext.__gregs[_REG_R11]
#define RETURNTO_FROM_UCONTEXT(context) (context)->uc_mcontext.__gregs[_REG_R14]
#elif defined(CPU_IS_IA64)
#define PC_FROM_UCONTEXT(context) (context)->_u._mc.sc_ip
#define STACK_FROM_UCONTEXT(context) (context)->_u._mc.sc_gr[12] //is that register 12?
#define FRAME_FROM_UCONTEXT(context) (context)->_u._mc.sc_cfm //does not really make sense
#elif defined(CPU_IS_MIPS)
#define PC_FROM_UCONTEXT(context) (context)->uc_mcontext.pc
#define STACK_FROM_UCONTEXT(context) (context)->uc_mcontext.sc_regs[29]
#define FRAME_FROM_UCONTEXT(context) (context)->uc_mcontext.sc_regs[30]
#define RETURNTO_FROM_UCONTEXT(context) (context)->uc_mcontext.sc_regs[31]
#elif defined(CPU_IS_SPARC32)
#define PC_FROM_UCONTEXT(context) (context)->uc_mcontext.gregs[REG_nPC]
#define STACK_FROM_UCONTEXT(context) (context)->uc_mcontext.gregs[REG_O6]
//todo: gwins-> might be 0. (first or last (context)->uc_mcontext.gwins[0].wbcnt-1 window?)
#define FRAME_FROM_UCONTEXT(context) (context)->uc_mcontext.gwins->wbuf[0].rw_in[6]
#define RETURNTO_FROM_UCONTEXT(context) (context)->uc_mcontext.gwins->wbuf[0].rw_in[7]
#elif defined(CPU_IS_S390_31) || defined(CPU_IS_S390_64)
#define PC_FROM_UCONTEXT(context) (context)->uc_mcontext.psw.addr
#define STACK_FROM_UCONTEXT(context) (context)->uc_mcontext.gregs[15]
#define FRAME_FROM_UCONTEXT(context) (context)->uc_mcontext.gregs[11]
//#define RETURNTO_FROM_UCONTEXT(context) (context)->uc_mcontext.gregs[14]
#else
#error Unknown cpu architecture
#endif

#define SIGMYHANG SIGRTMIN + 4             //signal send to the main thread, if the guardian detects an endless loop
#define SIGMYHANG_CONTINUE SIGRTMIN + 5    //signal send to the main thread, if the endless loop should be continued
#endif

#ifdef Q_OS_MAC
#include "signal.h"
//#include "ucontext.h"
#include "sys/signal.h"
#include "sys/ucontext.h"
#include "pthread.h"
#define USE_SIGNAL_HANDLER
//names from http://google-glog.googlecode.com/svn-history/r75/trunk/m4/pc_from_ucontext.m4
//for mac <= 10.4/tiger: if __ss.__ doesn't compile, replace it by ss.

#if defined(__DARWIN_UNIX03) && defined(_STRUCT_X86_EXCEPTION_STATE32)
#define MAC_CONTEXT_PREFIXED(x) __##x
#else
#define MAC_CONTEXT_PREFIXED(x) x
#endif

// >= mac 10.5
#ifdef CPU_IS_X86_64
#define PC_FROM_UCONTEXT(context) context->uc_mcontext->MAC_CONTEXT_PREFIXED(ss).MAC_CONTEXT_PREFIXED(rip)
#define STACK_FROM_UCONTEXT(context) context->uc_mcontext->MAC_CONTEXT_PREFIXED(ss).MAC_CONTEXT_PREFIXED(rsp)
#define FRAME_FROM_UCONTEXT(context) context->uc_mcontext->MAC_CONTEXT_PREFIXED(ss).MAC_CONTEXT_PREFIXED(rbp)
#elif defined(CPU_IS_PPC)
#define PC_FROM_UCONTEXT(context) context->uc_mcontext->MAC_CONTEXT_PREFIXED(ss).__srr0
#error need ppc stack register name
#elif defined(CPU_IS_X86_32)
#define PC_FROM_UCONTEXT(context) context->uc_mcontext->MAC_CONTEXT_PREFIXED(ss).MAC_CONTEXT_PREFIXED(eip)
#define STACK_FROM_UCONTEXT(context) context->uc_mcontext->MAC_CONTEXT_PREFIXED(ss).MAC_CONTEXT_PREFIXED(esp)
#define FRAME_FROM_UCONTEXT(context) context->uc_mcontext->MAC_CONTEXT_PREFIXED(ss).MAC_CONTEXT_PREFIXED(ebp)
#else
#error Unsupported processor architecture
#endif
#define SIGMYHANG SIGUSR1             //signal send to the main thread, if the guardian detects an endless loop
#define SIGMYHANG_CONTINUE SIGUSR2    //signal send to the main thread, if the endless loop should be continued
#endif

#ifdef USE_SIGNAL_HANDLER
#define CPU_CONTEXT_TYPE ucontext_t
volatile sig_atomic_t lastCrashSignal = 0;
#define SIGMYSTACKSEGV 123

#define LAST_POSSIBLE_TXS_ADDRESS ( ( (char*)&isAddressInTeXstudio) + 0x900000 )
//do not use etext, since it behaves funny (e.g. becomes 0 when including sys/ptrace)
//#define LAST_POSSIBLE_TXS_ADDRESS (&_etext)

CPU_CONTEXT_TYPE lastLoopContext;

bool isAddressInTeXstudio(void *address)
{
	return address < LAST_POSSIBLE_TXS_ADDRESS;
}


inline quintptr ptrdistance(void *a, void *b)
{
	if (a < b) return (quintptr)(b) - (quintptr)(a);
	else return (quintptr)(a) - (quintptr)(b);
}

const char *signalIdToName(int id)
{
	switch (id) {
	case SIGSEGV:
		return ("SIGSEGV");
	case SIGFPE:
		return ("SIGFPE");
	case SIGMYSTACKSEGV:
		return ("SIGSEGV on stack");
	//case SIGMYHANG: return "Endless loop";
	default:
		if (id == SIGMYHANG) return "Endless loop";
		else return ("SIG???");
	}
}

void signalHandler(int type, siginfo_t *si, void *ccontext)
{
	lastErrorType = ERR_SIGNAL;
	SimulatedCPU cpu;
	if (ccontext) {
		cpu.set_all(ccontext);
		if (cpu.frame == 0) cpu.frame = cpu.stack;

		if (type == SIGSEGV && sigSegvRecoverReturnAddress) {
			cpu.jmp((char *)sigSegvRecoverReturnAddress);
			sigSegvRecoverReturnAddress = 0;
			cpu.get_all(ccontext);
			return;
		}

		char *addr = (char *)(si->si_addr);
		char *minstack = cpu.stack < cpu.frame ? cpu.stack : cpu.frame;
		if (type == SIGSEGV && ptrdistance(addr, minstack) < 1024) type = SIGMYSTACKSEGV;
	}
	if (crashHandlerType & CRASH_HANDLER_PRINT_BACKTRACE_IN_HANDLER || !ccontext) {
		print_backtrace(signalIdToName(type));
		if (!ccontext) return;
	}
	if (crashHandlerType & CRASH_HANDLER_RECOVER) {
		if (type == SIGMYHANG) {
			if (!isAddressInTeXstudio(cpu.pc)) return; //don't mess with library functions
			lastLoopContext = *(static_cast<CPU_CONTEXT_TYPE *>(ccontext));
			lastErrorType = ERR_LOOP;
		} else if (type == SIGMYSTACKSEGV) cpu.unwindStack();

		lastCrashSignal = type;

		cpu.call((char *)(&recover));

		cpu.get_all(ccontext);
	}
}

void signalHandlerContinueHanging(int, siginfo_t *, void *ccontext)
{
	*(static_cast<CPU_CONTEXT_TYPE *>(ccontext)) = lastLoopContext;
}

const int SIGNAL_STACK_SIZE = 256 * 1024;
char staticSignalStack[SIGNAL_STACK_SIZE];
pthread_t mainThreadID;

void registerCrashHandler(int mode)
{
	if (mode >= 0) {
		stack_t ss;
		ss.ss_sp = staticSignalStack;
		ss.ss_size = SIGNAL_STACK_SIZE;
		ss.ss_flags = 0;
		sigaltstack(&ss, 0);

		struct sigaction sa;
		memset(&sa, 0, sizeof(sa));
		sa.sa_flags = SA_SIGINFO | SA_ONSTACK;
		sa.sa_sigaction = &signalHandler;
		sigaction(SIGSEGV, &sa, 0);
		sa.sa_sigaction = &signalHandler;
		sigaction(SIGFPE, &sa, 0);

		if (!(mode & CRASH_HANDLER_LOOP_GUARDIAN_DISABLED)) {
			sa.sa_sigaction = &signalHandler;
			sigaction(SIGMYHANG, &sa, 0);
			sa.sa_sigaction = &signalHandlerContinueHanging;
			sigaction(SIGMYHANG_CONTINUE, &sa, 0);
			mainThreadID = pthread_self();
		}
	}
}

QString getLastCrashInformationInternal()
{
	return signalIdToName(lastCrashSignal);
}


bool recoverMainThreadFromOutside()
{
	//fprintf(stderr, "%i -> %lx",SIGMYHANG, mainThreadID);
	lastErrorType = ERR_NONE;
	lastCrashSignal = 0;
	if (pthread_kill(mainThreadID, SIGMYHANG) != 0) return false;

	int loopend = 1000000;
	while ( !lastCrashSignal && (--loopend >= 0) ) ;
	__sync_synchronize(); //memory barrier (does it work?)  (better have a barrier here, than a lock in the signal handler)
	return lastErrorType == ERR_LOOP;
}

void undoMainThreadRecoveringFromOutside()
{
	pthread_kill(mainThreadID, SIGMYHANG_CONTINUE);
}

#endif


//=========================WINDOWS EXCEPTION HANDLER===========================

#ifdef Q_OS_WIN32

void *maxStack = 0;

#if 0
void printStackInfo()
{
	SYSTEM_INFO  si;
	MEMORY_BASIC_INFORMATION mi, info;
	GetSystemInfo(&si);
	for (int i = -2; i <= 32; i++) {
		bool allocated = VirtualQuery((char *)maxStack + i * si.dwPageSize, &info, sizeof(info));
		fprintf(stderr, "> %i: base: %p, allocbase: %p, size: %x, allocprotect: %x, protect: %x, state: %x\n",
		        allocated, info.BaseAddress, info.AllocationBase, info.RegionSize, info.AllocationProtect,  info.Protect, info.State);
	}
}
#endif

void myresetstkoflw()
{
	if (!maxStack) return;
	SYSTEM_INFO  si;
	GetSystemInfo(&si);


	MEMORY_BASIC_INFORMATION info;
	if (VirtualQuery(maxStack, &info, sizeof(info)) != sizeof(info)) return;

	//int pagesToFree = 16;
// allocated = VirtualFree(info.AllocationBase, pagesToFree * si.dwPageSize, MEM_DECOMMIT);
	//VirtualProtect((char*)info.AllocationBase + si.dwPageSize, si.dwPageSize, PAGE_NOACCESS, &tempi);
	//VirtualFree((char*)info.AllocationBase + si.dwPageSize, si.dwPageSize, MEM_DECOMMIT);
	//VirtualProtect((char*)info.AllocationBase + 2*si.dwPageSize, si.dwPageSize, PAGE_GUARD | PAGE_READWRITE, &tempi);
	DWORD tempi;
	//Just put that guard page back, where it was.
	VirtualProtect((char *)info.BaseAddress, si.dwPageSize, PAGE_GUARD | PAGE_READWRITE, &tempi);

	//printStackInfo();
}

void recoverWithStackGuardianPage()
{
	myresetstkoflw();
	//typedef int (*ResetstkoflwFunc) ();
	//ResetstkoflwFunc resetstkoflw = (ResetstkoflwFunc)(GetProcAddress(LoadLibraryA("msvcr70.dll"), "_resetstkoflw"));
	//if (resetstkoflw) (*resetstkoflw)();
	recover();
}

#define CATCHED_EXCEPTIONS(X)  \
	X(EXCEPTION_ACCESS_VIOLATION) 	X(EXCEPTION_ARRAY_BOUNDS_EXCEEDED) X(EXCEPTION_DATATYPE_MISALIGNMENT) \
	X(EXCEPTION_FLT_DENORMAL_OPERAND) 	X(EXCEPTION_FLT_DIVIDE_BY_ZERO) X(EXCEPTION_FLT_INEXACT_RESULT) \
	X(EXCEPTION_FLT_INVALID_OPERATION) X(EXCEPTION_FLT_OVERFLOW) X(EXCEPTION_FLT_UNDERFLOW) \
	X(EXCEPTION_IN_PAGE_ERROR) \
	X(EXCEPTION_INT_DIVIDE_BY_ZERO) X(EXCEPTION_INT_OVERFLOW) \
	X(EXCEPTION_INVALID_DISPOSITION) \
	X(EXCEPTION_FLT_STACK_CHECK)  X(EXCEPTION_STACK_OVERFLOW)
//EXCEPTION_ILLEGAL_INSTRUCTION
//EXCEPTION_NONCONTINUABLE_EXCEPTION
//EXCEPTION_PRIV_INSTRUCTION
#ifdef CPU_IS_X86_64
#define PC_FROM_UCONTEXT(context) (context)->Rip
#define FRAME_FROM_UCONTEXT(context) (context)->Rbp
#define STACK_FROM_UCONTEXT(context) (context)->Rsp
#elif defined(CPU_IS_X86_32)
#define PC_FROM_UCONTEXT(context) (context)->Eip
#define FRAME_FROM_UCONTEXT(context) (context)->Ebp
#define STACK_FROM_UCONTEXT(context) (context)->Esp
#else
#error Unsupported processor architecture
#endif


const char *exceptionCodeToName(int code)
{
	switch (code) {
#define X(t) case t: return #t;
		CATCHED_EXCEPTIONS(X)
#undef X
	}
	return "unknown";
}


int lastExceptionCode = 0;
quintptr lastExceptionAddress = 0;

LONG WINAPI crashHandler(_EXCEPTION_POINTERS *ExceptionInfo)
{
	if (!ExceptionInfo) return EXCEPTION_CONTINUE_SEARCH;
	bool isCatched = false;
#define X(t) if (ExceptionInfo->ExceptionRecord->ExceptionCode == t) isCatched = true;
	CATCHED_EXCEPTIONS(X)
#undef X

	if (!isCatched) return EXCEPTION_CONTINUE_SEARCH;

	if ((ExceptionInfo->ExceptionRecord->ExceptionCode == EXCEPTION_ACCESS_VIOLATION || ExceptionInfo->ExceptionRecord->ExceptionCode == EXCEPTION_STACK_OVERFLOW)
	        && sigSegvRecoverReturnAddress) {
		SimulatedCPU cpu;
		cpu.set_all(ExceptionInfo->ContextRecord);
		cpu.jmp((char *)sigSegvRecoverReturnAddress);
		sigSegvRecoverReturnAddress = 0;
		cpu.get_all(ExceptionInfo->ContextRecord);
		return EXCEPTION_CONTINUE_EXECUTION;
	}

	//if (ExceptionInfo->ExceptionRecord->ExceptionCode == EXCEPTION_ACCESS_VIOLATION) print_backtrace("");

	lastErrorType = ERR_SIGNAL;

	if (crashHandlerType & CRASH_HANDLER_PRINT_BACKTRACE_IN_HANDLER) {
		print_backtrace(exceptionCodeToName(ExceptionInfo->ExceptionRecord->ExceptionCode));
	}


	if (crashHandlerType & CRASH_HANDLER_RECOVER) {
		lastExceptionCode = ExceptionInfo->ExceptionRecord->ExceptionCode;

		SimulatedCPU cpu;
		cpu.set_all(ExceptionInfo->ContextRecord);

		lastExceptionAddress = (quintptr)(cpu.pc);

		if (ExceptionInfo->ExceptionRecord->ExceptionCode == EXCEPTION_STACK_OVERFLOW || ExceptionInfo->ExceptionRecord->ExceptionCode == EXCEPTION_FLT_STACK_CHECK) {
			maxStack = cpu.stack;
			cpu.unwindStack();
			cpu.call((char *)&recoverWithStackGuardianPage);
		} else {
			cpu.call((char *)&recover);
		}

		cpu.get_all(ExceptionInfo->ContextRecord);

		return EXCEPTION_CONTINUE_EXECUTION;
	}

	return EXCEPTION_CONTINUE_SEARCH;
}

#include "psapi.h"
typedef BOOL WINAPI (*GetModuleInformationFunc)(HANDLE hProcess, HMODULE hModule, LPMODULEINFO lpmodinfo, DWORD cb );
typedef WINBASEAPI HANDLE WINAPI (*OpenThreadFunc)(DWORD, BOOL, DWORD);


void *ownBaseAddress = 0;
unsigned int ownSize = 0x01000000;
DWORD mainThreadID = 0;
OpenThreadFunc OpenThreadDyn;

void registerCrashHandler(int mode)
{
	if (mode >= 0) {
		SetUnhandledExceptionFilter(&crashHandler);

		if (!(mode & CRASH_HANDLER_LOOP_GUARDIAN_DISABLED)) {
			OpenThreadDyn = (OpenThreadFunc)(GetProcAddress(GetModuleHandleA("kernel32.dll"), "OpenThread"));

			if (OpenThreadDyn) {
				mainThreadID = GetCurrentThreadId();
				MODULEINFO moduleInfo;
				HMODULE psapi = LoadLibraryA("psapi.dll");
				GetModuleInformationFunc GetModuleInformation = (GetModuleInformationFunc)(GetProcAddress(psapi, "K32GetModuleInformation"));
				if (!GetModuleInformation) GetModuleInformation = (GetModuleInformationFunc)(GetProcAddress(psapi, "GetModuleInformation"));
				if ((*GetModuleInformation)(GetCurrentProcess(), GetModuleHandle(0), &moduleInfo, sizeof(moduleInfo))) {
					ownBaseAddress = moduleInfo.lpBaseOfDll;
					ownSize = moduleInfo.SizeOfImage;
				}
			}
		}
	}
}

QString getLastCrashInformationInternal()
{
	return QString::fromLocal8Bit(exceptionCodeToName(lastExceptionCode)) + " at " + QString::number(lastExceptionAddress, 16);
}


bool isAddressInTeXstudio(char *address)
{
	return address >= ownBaseAddress && address <= ((char *)ownBaseAddress) + ownSize;
}

typedef bool (*ChangeThreadContextFunc)(HANDLE thread, CONTEXT *c);

bool doSomethingWithMainThreadContext(ChangeThreadContextFunc something)
{
	if (!mainThreadID || !OpenThreadDyn) return false;
	HANDLE mainThread = (*OpenThreadDyn)(THREAD_GET_CONTEXT | THREAD_QUERY_INFORMATION | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME, false, mainThreadID);
	if (!mainThread) return false;
	bool result = false;
	SuspendThread(mainThread);
	CONTEXT c;
	c.ContextFlags = (CONTEXT_FULL);
	if (GetThreadContext(mainThread, &c))
		result = (*something)(mainThread, &c);
	ResumeThread(mainThread);
	CloseHandle(mainThread);
	return result;
}

CONTEXT lastRecoveredContext;
bool changeContextToRecover(HANDLE thread, CONTEXT *c)
{
	bool result = false;
	if (isAddressInTeXstudio((char *)(PC_FROM_UCONTEXT(c)))) {
		lastRecoveredContext = *c;
		SimulatedCPU cpu;
		cpu.set_all(c);
		cpu.call((char *)&recover);
		cpu.get_all(c);
		result = SetThreadContext(thread, c);
		if (result) lastErrorType = ERR_LOOP;
	}
	return result;
}

bool recoverMainThreadFromOutside()
{
	return doSomethingWithMainThreadContext(changeContextToRecover);
}

bool changeContextToUndoRecoving(HANDLE thread, CONTEXT *c)
{
	Q_UNUSED(c);
	return SetThreadContext(thread, &lastRecoveredContext);
}

void undoMainThreadRecoveringFromOutside()
{
	doSomethingWithMainThreadContext(changeContextToUndoRecoving);
}
#endif


#if !defined(USE_SIGNAL_HANDLER) && !defined(Q_OS_WIN32)
#warning Unrecognized OS. Crash handler will be disabled.

bool recoverMainThreadFromOutside()
{
	fprintf(stderr, "Main thread locks frozen\n");
	return true;
}

void undoMainThreadRecoveringFromOutside() {}
QString getLastCrashInformationInternal()
{
	return "unknown (os unsupported by crash handler)";
}

void registerCrashHandler(int mode) {}
#endif


//========================NEW ASSERT==============================


#undef qt_assert
Q_CORE_EXPORT void qt_assert(const char *assertion, const char *file, int line) ASSERT_THROW ;
Q_CORE_EXPORT void qt_assert_x(const char *where, const char *what, const char *file, int line) ASSERT_THROW ;

QString lastAssert;

void txs_assert_x(const char *where, const char *assertion, const char *file, int line) ASSERT_THROW
{
	lastAssert = QString("Assert failure: %1 at %2 in %3:%4").arg(assertion).arg(where).arg(file).arg(line);
	print_backtrace(lastAssert);

	lastErrorType = ERR_ASSERT;
	recover();

	//won't be called:
	qt_assert(assertion, file, line);
	exit(1);
}

void txs_assert(const char *assertion, const char *file, int line) ASSERT_THROW
{
	txs_assert_x("something", assertion, file, line);
}

QString getLastCrashInformation(bool &wasLoop)
{
	wasLoop = lastErrorType == ERR_LOOP;
	switch (lastErrorType) {
	case ERR_ASSERT:
		return lastAssert;
	case ERR_EXCEPTION:
		return "c++ exception";
	default:
		return getLastCrashInformationInternal();
	}
}



//======================== CPU Information ==============================

#ifdef CPU_CONTEXT_TYPE

void SimulatedCPU::set_all(void *ccontext)
{
	CPU_CONTEXT_TYPE *context = static_cast<CPU_CONTEXT_TYPE *>(ccontext);
	this->pc = (char *)PC_FROM_UCONTEXT(context);
	this->frame = (char *)FRAME_FROM_UCONTEXT(context);
	this->stack = (char *)STACK_FROM_UCONTEXT(context);
#ifdef RETURNTO_FROM_UCONTEXT
	this->returnTo = (char *)RETURNTO_FROM_UCONTEXT(context);
#endif
//	for (int i=0;i<sizeof(context->uc_mcontext.gregs) / sizeof(context->uc_mcontext.gregs[0]);i++)
//		fprintf(stderr, "Regs: %i: %p\n", i, context->uc_mcontext.gregs[i]);
}


void SimulatedCPU::get_all(void *ccontext)
{
	CPU_CONTEXT_TYPE *context = static_cast<CPU_CONTEXT_TYPE *>(ccontext);
	memcpy(&PC_FROM_UCONTEXT(context), &this->pc, sizeof(char*));
	memcpy(&FRAME_FROM_UCONTEXT(context), &this->frame, sizeof(char*));
	memcpy(&STACK_FROM_UCONTEXT(context), &this->stack, sizeof(char*));
#ifdef RETURNTO_FROM_UCONTEXT
	memcpy(&RETURNTO_FROM_UCONTEXT(context), &this->returnTo, sizeof(char*));
#endif
}

void SimulatedCPU::set_from_real()
{
	this->pc = 0;
	this->frame = 0;
	this->stack = 0;
#ifdef CPU_IS_X86_32
	__asm__(
	    "mov %%ebp, %0\n"
	    "mov %%esp, %1"
	    : "=r"(frame), "=r"(stack));
#elif defined(CPU_IS_X86_64)
	__asm__(
	    "mov %%rbp, %0\n"
	    "mov %%rsp, %1"
	    : "=r"(frame), "=r"(stack));
#elif defined(CPU_IS_ARM)
	__asm__( //otherway around in the mov than x86?
	    "mov %[fp], fp\n"
	    "mov %[sp], sp\n"
	    "mov %[lr], lr\n"
	    : [fp] "=r"(frame), [sp] "=r"(stack), [lr] "=r" (returnTo));
#elif defined(CPU_IS_IA64)
	__asm__(
	    //"mov %0 = cfm\n"
	    "mov %0 = r12"
	    : /*"=r"(frame),*/ "=r"(stack));
#elif defined(CPU_IS_MIPS)
	__asm__( //otherway around in the mov than x86?
	    "move %0, $30\n"
	    "move %1, $sp\n"
	    "move %2, $ra\n"
	    : "=r"(frame), "=r"(stack), "=r" (returnTo));
#elif defined(CPU_IS_PPC)
	__asm__( //otherway around in the mov than x86?
	    "mr %0, 31\n"
	    "mr %1, 1\n"
	    "mflr %2\n"
	    : "=r"(frame), "=r"(stack), "=r" (returnTo));
#elif defined(CPU_IS_SPARC32)
	__asm__(
	    "mov %i6, %0\n"
	    "mov %o6, %1\n"
	    "mov %i7, %2\n"
	    : "=r"(frame), "=r"(stack), "=r" (returnTo));
#elif defined(CPU_IS_S390_31)
	__asm__(
	    "LR %0, %r11\n"
	    "LR %1, %r15\n"
	    : "=r"(frame), "=r"(stack));
#elif defined(CPU_IS_S390_64)
	__asm__(
	    "LGR %0, %r11\n"
	    "LGR %1, %r15\n"
	    : "=r"(frame), "=r"(stack));
#else
#error Unknown processor architecture
#endif

#undef geteip
	
geteip:
	this->pc = (char *) && geteip;
}

#endif

//todo: fix CALL_INSTRUCTION_SIZE
//(should be the size of the call instruction.
//however, since the call instruction is in the signal handler and not actually part of the program, 0 might be the more correct value)
#define CALL_INSTRUCTION_SIZE 0
#if defined(CPU_IS_X86_64) || defined (CPU_IS_X86_32)
//TODO: check ppc
void SimulatedCPU::call(char *value)
{
	push(pc + CALL_INSTRUCTION_SIZE);
	jmp(value);
}

void SimulatedCPU::ret()
{
	pc = pop();
}

void SimulatedCPU::enter(int size)
{
	push(frame);
	frame = stack;
	stack -= size;
}

void SimulatedCPU::leave()
{
	sigSegvRecoverReturnAddress = && recover;
	stack = frame;
	frame = pop();
	ret();
recover:
	if (sigSegvRecoverReturnAddress == 0) {
		frame = 0;
		stack = 0;
		pc = 0;
	}
	sigSegvRecoverReturnAddress = 0;
}

#elif defined(CPU_IS_ARM) || defined(CPU_IS_MIPS)
//todo: does this work on mips?
void SimulatedCPU::call(char *value)     //bl
{
	returnTo = pc + CALL_INSTRUCTION_SIZE;
	jmp(value);
}

void SimulatedCPU::ret()
{
	pc = returnTo;
}

void SimulatedCPU::enter(int size)
{
	push(returnTo);
	push(frame);
	frame = stack + 4;
	stack -= size;
}

void SimulatedCPU::leave()
{
	stack = frame - 4;
	frame = pop();
	returnTo = pop();
	ret();
}

#elif defined(CPU_IS_PPC)

//see https://developer.apple.com/library/mac/#documentation/DeveloperTools/Conceptual/LowLevelABI/110-64-bit_PowerPC_Function_Calling_Conventions/64bitPowerPC.html#//apple_ref/doc/uid/TP40002471-SW14
void SimulatedCPU::call(char *value)     //bl
{
	returnTo = pc + CALL_INSTRUCTION_SIZE;
	jmp(value);
}

void SimulatedCPU::ret()
{
	pc = returnTo;
}

void SimulatedCPU::enter(int size)
{
	//todo
}

void SimulatedCPU::leave()
{
	returnTo = *(char **)(stack + 2 * 8);
	stack = pop();
	frame = stack; //??
	ret();
}

#elif defined(CPU_IS_IA64) || defined(CPU_IS_SPARC32) || defined(CPU_IS_S390_31) || defined(CPU_IS_390_64)

//not really implemented
//not possible on SPARC? (as register windows are protected)
void SimulatedCPU::call(char *value)     //bl
{
	jmp(value);
	//todo this should do an awful lot of register swapping/saving for IA64
}

void SimulatedCPU::ret()
{
	//pc = br0;
	pc = 0;
}

void SimulatedCPU::enter(int size)
{

}
void SimulatedCPU::leave()
{
	ret();
}

#else
#error Unknown cpu architecture
#endif

bool SimulatedCPU::stackWalk()
{
	leave();
	pc -= CALL_INSTRUCTION_SIZE;
//	fprintf(stderr, "%p (at %p), %p (at %p), %p\n", *(char**)(frame),frame, *(char**)(stack), stack, pc);
	return frame >= stack && frame && stack;
}

void catchUnhandledException()
{
	lastErrorType = ERR_EXCEPTION;
	recover();
}

#else
// defined NO_CRASH_HANDLER

QString print_backtrace(const QString &message)
{
	Q_UNUSED(message) return "";
}

void registerCrashHandler(int mode)
{
	Q_UNUSED(mode)
}QString getLastCrashInformation(bool &wasLoop)
{
	Q_UNUSED(wasLoop);
	return "";
}

void catchUnhandledException() {}

#endif


#ifdef HAS_DEBUGGER_PRESENT
#undef HAS_DEBUGGER_PRESENT
#endif


#ifdef Q_OS_WIN32
#define HAS_DEBUGGER_PRESENT
#else
#if (!defined(QT_NO_DEBUG) && defined(Q_OS_LINUX))
#define HAS_DEBUGGER_PRESENT
#include <sys/ptrace.h>
//from http://stackoverflow.com/questions/3596781/detect-if-gdb-is-running

#ifndef NO_CRASH_HANDLER
int gdb_check()
{
	pid_t pid = fork();
	int status;
	int res;

	if (pid == -1) {
		perror("fork");
		return -1;
	}

	if (pid == 0) {
		pid_t ppid = getppid();
		/* Child */
		if (ptrace(PTRACE_ATTACH, ppid, NULL, NULL) == 0) {
			/* Wait for the parent to stop and continue it */
			waitpid(ppid, NULL, 0);
			ptrace(PTRACE_CONT, ppid, NULL, NULL);

			/* Detach */
			ptrace(PTRACE_DETACH, ppid, NULL, NULL);

			/* We were the tracers, so gdb is not present */
			res = 0;
		} else {
			/* Trace failed so gdb is present */
			res = 1;
		}
		_Exit(res);
	} else {
		waitpid(pid, &status, 0);
		res = WEXITSTATUS(status);
	}
	return res;
}

int _debugger_present = -1;
bool IsDebuggerPresent()
{
	if (-1 == _debugger_present)
		_debugger_present = gdb_check();
	if (_debugger_present == 1)  {
		fprintf(stderr, "debugger detected: no recovering\n\n");
		fflush(stderr);
	}
	return _debugger_present == 1;
}
#endif
#endif
#endif

void initCrashHandler(int mode)
{
#ifndef NO_CRASH_HANDLER
	crashHandlerType = mode;
	registerCrashHandler(mode);
	if (mode >= 0) std::set_terminate(&catchUnhandledException);
#else
	Q_UNUSED(mode);
#endif
}


//==================GUARDIAN==================

Guardian *guardian = 0;
bool running = true;
volatile int mainEventLoopTicks = 0;
volatile bool undoRecovering = false;

void Guardian::run()
{
#ifndef NO_CRASH_HANDLER
	int lastTick = mainEventLoopTicks;
	int errors = 0;
	while (running) {
		int slowOperationWait = slowOperations * 15;
		do {
			sleep(10);
			slowOperationWait -= 1;
		} while (slowOperationWait >= 0);

		if (undoRecovering) {
			undoRecovering = false;
			errors = 1;
			undoMainThreadRecoveringFromOutside();
			continue;
		}
		if (crashHandlerType & CRASH_HANDLER_LOOP_GUARDIAN_DISABLED) continue;
		if (lastTick == mainEventLoopTicks) errors++;
		else errors = 0;
		lastTick = mainEventLoopTicks;
		if (errors >= 60) {
			fprintf(stderr, "Main thread in trouble\n");
#ifdef HAS_DEBUGGER_PRESENT
			if (IsDebuggerPresent()) return;
#endif
			int repetitions = 0;
			while (lastTick == mainEventLoopTicks && !recoverMainThreadFromOutside()) {
				msleep(50);
				repetitions ++;
				if (repetitions > 50) break;  //give up for now
			}
			if (repetitions < 50) //recovered
				errors -= 6 ; //wait 1 min now
			//if (repetitions < 50) return; the crash handler can't be debugged, if this thread continues calling it
		}
	}
	guardian = 0;
#endif
}

void Guardian::summon()
{
#ifndef NO_CRASH_HANDLER
	if (guardian) return;
	if (crashHandlerType & CRASH_HANDLER_LOOP_GUARDIAN_DISABLED) return;
	guardian = new Guardian();
	guardian->start();
#endif
}

void Guardian::calm()
{
	mainEventLoopTicks++;
}

void Guardian::shutdown()
{
	running = false;
}

void Guardian::continueEndlessLoop()
{
	undoRecovering = true;
}

Guardian *Guardian::instance()
{
	return guardian;
}

void Guardian::slowOperationStarted()
{
	slowOperations++;
}

void Guardian::slowOperationEnded()
{
	slowOperations--;
	if (slowOperations < 0) slowOperations = 0;
}


