/**
 * @file llwindebug.cpp
 * @brief Windows debugging functions
 *
 * $LicenseInfo:firstyear=2004&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * 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;
 * version 2.1 of the License only.
 * 
 * This library 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 library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */
#include "llviewerprecompiledheaders.h"

#include "llwindebug.h"
#include "lldir.h"


// based on dbghelp.h
typedef BOOL (WINAPI *MINIDUMPWRITEDUMP)(HANDLE hProcess, DWORD dwPid, HANDLE hFile, MINIDUMP_TYPE DumpType,
									CONST PMINIDUMP_EXCEPTION_INFORMATION ExceptionParam,
									CONST PMINIDUMP_USER_STREAM_INFORMATION UserStreamParam,
									CONST PMINIDUMP_CALLBACK_INFORMATION CallbackParam
									);

MINIDUMPWRITEDUMP f_mdwp = NULL;


class LLMemoryReserve {
public:
	LLMemoryReserve();
	~LLMemoryReserve();
	void reserve();
	void release();
private:
	unsigned char *mReserve;
	static const size_t MEMORY_RESERVATION_SIZE;
};

LLMemoryReserve::LLMemoryReserve() :
	mReserve(NULL)
{
}

LLMemoryReserve::~LLMemoryReserve()
{
	release();
}

// I dunno - this just seemed like a pretty good value.
const size_t LLMemoryReserve::MEMORY_RESERVATION_SIZE = 5 * 1024 * 1024;

void LLMemoryReserve::reserve()
{
	if(NULL == mReserve)
	{
		mReserve = new unsigned char[MEMORY_RESERVATION_SIZE];
	}
}

void LLMemoryReserve::release()
{
	if (NULL != mReserve)
	{
		delete [] mReserve;
	}
	mReserve = NULL;
}

static LLMemoryReserve gEmergencyMemoryReserve;


LONG NTAPI vectoredHandler(PEXCEPTION_POINTERS exception_infop)
{
	LLWinDebug::instance().generateMinidump(exception_infop);
	return EXCEPTION_CONTINUE_SEARCH;
}

// static
void  LLWinDebug::initSingleton()
{
	static bool s_first_run = true;
	// Load the dbghelp dll now, instead of waiting for the crash.
	// Less potential for stack mangling

	// Don't install vectored exception handler if being debugged.
	if(IsDebuggerPresent()) return;

	if (s_first_run)
	{
		// First, try loading from the directory that the app resides in.
		std::string local_dll_name = gDirUtilp->findFile("dbghelp.dll", gDirUtilp->getWorkingDir(), gDirUtilp->getExecutableDir());

		HMODULE hDll = NULL;
		hDll = LoadLibraryA(local_dll_name.c_str());
		if (!hDll)
		{
			hDll = LoadLibrary(L"dbghelp.dll");
		}

		if (!hDll)
		{
			LL_WARNS("AppInit") << "Couldn't find dbghelp.dll!" << LL_ENDL;
		}
		else
		{
			f_mdwp = (MINIDUMPWRITEDUMP) GetProcAddress(hDll, "MiniDumpWriteDump");

			if (!f_mdwp)
			{
				FreeLibrary(hDll);
				hDll = NULL;
			}
		}

		gEmergencyMemoryReserve.reserve();

		s_first_run = false;

		// Add this exeption hanlder to save windows style minidump.
		AddVectoredExceptionHandler(0, &vectoredHandler);
	}
}

void LLWinDebug::cleanupSingleton()
{
	gEmergencyMemoryReserve.release();
}

void LLWinDebug::writeDumpToFile(MINIDUMP_TYPE type, MINIDUMP_EXCEPTION_INFORMATION *ExInfop, const std::string& filename)
{
	// Temporary fix to switch out the code that writes the DMP file.
	// Fix coming that doesn't write a mini dump file for regular C++ exceptions.
	const bool enable_write_dump_file = false;
	if ( enable_write_dump_file )
	{
		if(f_mdwp == NULL || gDirUtilp == NULL)
		{
			return;
		}
		else
		{
			std::string dump_path = gDirUtilp->getExpandedFilename(LL_PATH_LOGS, filename);

			HANDLE hFile = CreateFileA(dump_path.c_str(),
										GENERIC_WRITE,
										FILE_SHARE_WRITE,
										NULL,
										CREATE_ALWAYS,
										FILE_ATTRIBUTE_NORMAL,
										NULL);

			if (hFile != INVALID_HANDLE_VALUE)
			{
				// Write the dump, ignoring the return value
				f_mdwp(GetCurrentProcess(),
						GetCurrentProcessId(),
						hFile,
						type,
						ExInfop,
						NULL,
						NULL);

				CloseHandle(hFile);
			}

		}
	}
}

// static
void LLWinDebug::generateMinidump(struct _EXCEPTION_POINTERS *exception_infop)
{
	std::string dump_path = gDirUtilp->getExpandedFilename(LL_PATH_LOGS,
												"AlchemyException");
	if (exception_infop)
	{
		// Since there is exception info... Release the hounds.
		gEmergencyMemoryReserve.release();

		_MINIDUMP_EXCEPTION_INFORMATION ExInfo;

		ExInfo.ThreadId = ::GetCurrentThreadId();
		ExInfo.ExceptionPointers = exception_infop;
		ExInfo.ClientPointers = NULL;
		writeDumpToFile((MINIDUMP_TYPE)(MiniDumpWithDataSegs | MiniDumpWithIndirectlyReferencedMemory), &ExInfo, "Alchemy.dmp");
	}
}
