gapp.cpp

一个非常有用的开源代码

/*
	Copyright (C) 2006, Mike Gashler

	This library 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 2.1 of the License, or (at your option) any later version.

	see http://www.gnu.org/copyleft/lesser.html
*/

#include "GApp.h"
#include <stdio.h>
#include <stdlib.h>
#ifdef WIN32
#	include <windows.h>
#	include <direct.h>
#else // WIN32
#	include <unistd.h>
#	include <signal.h>
#endif // !WIN32
#include "GMacros.h"
#include "GFile.h"

/*static*/ int GApp::LaunchDaemon(DaemonMainFunc pDaemonMain, void* pArg)
{
#ifdef WIN32
	// Windows isn't POSIX compliant and it has its own process system that
	// isn't really friendly to launching daemons.  You're supposed to create
	// a "service", but I don't know how to do that (and I'm too lazy to learn
	// something that can't generalize off a proprietary platform) so let's
	// just launch it like a normal app and be happy with that.
	pDaemonMain(pArg);
	return 0;
#else // WIN32
	// Fork the process
	int pid = fork();
	if(pid < 0)
		throw "Error forking the daemon process";
	if(pid == 0)
	{
		// Drop my process group leader and become my own process group leader
		// (so the process isn't terminated when the group leader is killed)
		setsid();

		// Get off any mounted drives so that they can be unmounted without
		// killing the daemon
		chdir("/");

		// Launch the daemon
		pDaemonMain(pArg);

		exit(0);
	}
	return pid;
#endif // !WIN32
}

/*static*/ char* GApp::GetApplicationPath(const char* szArg0)
{
	// Make sure the app name includes path info
	char szAppPath[512];
#ifdef WIN32
	GetModuleFileName(NULL, szAppPath, 512);
#else // WIN32
	if(szArg0[0] == '/')
		strcpy(szAppPath, szArg0);
	else
	{
		getcwd(szAppPath, 512);
		if(szAppPath[strlen(szAppPath) - 1] != '/')
			strcat(szAppPath, "/");
		strcat(szAppPath, szArg0);
	}
#endif // !WIN32

	// Cut off the filename
	int n = strlen(szAppPath);
	for(n--; n >= 0; n--)
	{
		if(szAppPath[n] == '/' || szAppPath[n] == '\\')
		{
			szAppPath[n + 1] = '\0';
			break;
		}
	}
	if(n < 0)
	{
		getcwd(szAppPath, 512);
		n = strlen(szAppPath) - 1;
		if(szAppPath[n] != '/' && szAppPath[n] != '\\')
			strcat(szAppPath, "/");
	}

	// Copy to an allocated buffer
	GFile::CondensePath(szAppPath);
	char* szApplicationPath = new char[strlen(szAppPath) + 1];
	strcpy(szApplicationPath, szAppPath);
	return szApplicationPath;
}

void GApp_onSigSegV(int n)
{
	throw "A memory access violation occurred.  The most common cause is an attempt to dereference null";
}

void GApp_onSigInt(int n)
{
	throw "The program was interrupted when the user pressed Ctrl-C";
}

void GApp_onSigQuit(int n)
{
	throw "The program was interrupted with SIGQUIT";
}

void GApp_onSigTstp(int n)
{
	throw "The program was interrupted with SIGTSTP";
}

void GApp_onSigAbrt(int n)
{
	throw "An unhandled exception was thrown";
}

void GApp_onSigFpe(int n)
{
	throw "A floating point error occurred";
}

/*static*/ void GApp::TurnSegFaultsIntoExceptions()
{
#ifndef WIN32
	signal(SIGSEGV, GApp_onSigSegV);
	signal(SIGINT, GApp_onSigInt);
	signal(SIGFPE, GApp_onSigFpe);
	//signal(SIGQUIT, GApp_onSigQuit);
	//signal(SIGTSTP, GApp_onSigTstp);
	//signal(SIGABRT, GApp_onSigAbrt);
#endif // !WIN32
}