//
// C++ Implementation: iomanager
//
// Description: 
//
//
// Author: Jason Rodriguez <jrodriguez@calpont.com>
//
// Copyright: Calpont, Inc, (C) 2007
//
//

#define _FILE_OFFSET_BITS 64
#define _LARGEFILE64_SOURCE
#include <stdexcept>
#include <iostream>
#include <unistd.h>
#include <stdlib.h>
#include <string>
#include <sstream>
#include <map>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <boost/scoped_array.hpp>

using namespace std;

#include "configcpp.h"
using namespace config;

#include "iomanager.h"
namespace {

using namespace dbbc;
using namespace std;

unsigned pageSize; // = getpagesize();

// #define FDCACHE

/* structures shared across all iomanagers */
#ifdef FDCACHE
map<uint32_t, int> fdcache;
pthread_mutex_t fdMutex = PTHREAD_MUTEX_INITIALIZER;
#endif

void* thr_popper(void* arg) {
	ioManager* iom = (ioManager*)arg;
	FileBufferMgr* fbm;
	int totalRqst=0;
	fileRequest* fr=NULL;
	BRM::LBID_t lbid=0;
	BRM::OID_t oid=0;
	BRM::VER_t ver=0; 
	int blocksLoaded=0;
	const unsigned pageSize = getpagesize();
	fbm = &iom->fileBufferManager();
	char fileName[WriteEngine::FILE_NAME_SIZE];
	const uint64_t fileBlockSize = BLOCK_SIZE;
	uint32_t offset=0;
	bool flg=false;
	char* fileNamePtr=fileName;
	uint64_t longSeekOffset=0;
	int dlen=0, i, err;
	uint acc;
	uint32_t sz=0, readSize;
	char* alignedbuff=NULL;
// 	char realbuff[(fileBlockSize)+pageSize] __attribute__((aligned)); //doesn't align enough, but is a start...
 	boost::scoped_array<char> realbuff;	
	uint extentSize = iom->getExtentSize();
#ifdef FDCACHE
	map<uint32_t, int>::iterator fdit;
#endif
	int fd;

	// the largest read
	realbuff.reset(new char[(extentSize * BLOCK_SIZE) + pageSize]);

	for ( ; ; ) {

		fr = iom->getNextRequest();
		lbid = fr->Lbid();
		ver = fr->Ver();
		flg = fr->Flg();
		blocksLoaded=0;
		
		err = iom->lbidLookup(lbid, ver, flg, oid, offset);
		if (err < 0) {
			cerr << "lbid=" << lbid << " ver=" << ver << " flg=" << (flg ? 1 : 0) << endl;
			throw runtime_error("thr_popper: BRM lookup failure");
		}

#ifdef FDCACHE
		pthread_mutex_lock(&fdMutex);
		fdit = fdcache.find(oid);
		if (fdit == fdcache.end()) {
#endif
			try {
				iom->buildOidFileName(oid, fileNamePtr);
			} catch (exception& exc)
			{
				cerr << "FileName Err:" << exc.what() << endl;
			}
			fd = open(fileNamePtr, O_RDONLY|O_DIRECT|O_LARGEFILE|O_NOATIME);
			if (fd<0)
				throw runtime_error("Error opening file");
#ifdef FDCACHE
			fdcache[oid] = fd;
		}
		else 
			fd = fdit->second;
		pthread_mutex_unlock(&fdMutex);
#endif

		longSeekOffset=(uint64_t)offset * (uint64_t)fileBlockSize;
		lseek64(fd, longSeekOffset, SEEK_SET);
		totalRqst++;
		dlen = (fr->BlocksRequested() > extentSize ? extentSize : fr->BlocksRequested());
		sz=0;

		readSize = dlen * BLOCK_SIZE;
		if (realbuff == NULL) {
			cerr << "thr_popper: Can't allocate space for a whole extent in memory" << endl;
			return NULL;
		}

#if __WORDSIZE > 32
		alignedbuff=(char*)((((ptrdiff_t)&realbuff[0] + pageSize - 1) / pageSize) * pageSize);
#else
		alignedbuff=(char*)(((((ptrdiff_t)&realbuff[0] & 0xffffffff) + pageSize - 1) / pageSize) * pageSize);
#endif
//			Uncomment these assertions if necessary...
//  		assert(((ptrdiff_t)alignedbuff - (ptrdiff_t)realbuff) < (ptrdiff_t)pageSize);

		//these 2 things need to be true for O_DIRECT read to work
//  		assert((fileBlockSize % pageSize) == 0);
//  		assert(((ptrdiff_t)alignedbuff % pageSize) == 0);

 		if (dlen > 1)
 			cerr << "thrpopper: multiblock read of " << dlen << " readsize = " << 
				readSize << endl;

		acc = 0;
		while (acc < readSize) {
// 			cerr << "reading " << readSize-acc << "/" << readSize << endl;
			i = read(fd, &alignedbuff[acc], readSize - acc);
			/* XXXPAT: Need to decide how to handle errors here */
			if (i < 0 && errno == EINTR)
				continue;
			else if (i < 0) {
				perror("thr_popper::read");
				return NULL;			// shuts down this thread, 
								// probably not the right thing to do
			}
			else if (i == 0) {
				try {
					iom->buildOidFileName(oid, fileNamePtr);
				} catch (exception& exc)
				{
					cerr << "FileName Err:" << exc.what() << endl;
				}
				cerr << "thr_popper: Early EOF in file " << fileNamePtr << endl;
				return NULL;
			}
			acc += i;
		}

		for (i = 0; i < dlen; ++i) {
			fbm->insert(FileBuffer(fr->Lbid() + i, fr->Ver(), 
				(uint8_t *) &alignedbuff[i*BLOCK_SIZE], BLOCK_SIZE));
			++blocksLoaded;
		}

		if (fr->data != NULL && dlen == 1)
			memcpy(fr->data, alignedbuff, BLOCK_SIZE);

#ifndef FDCACHE
 		close(fd);
#endif

		fr->RequestStatus(fileRequest::SUCCESSFUL);

		pthread_mutex_lock(&fr->frMutex());
		fr->SetPredicate(fileRequest::COMPLETE);
		pthread_cond_signal(&fr->frCond());
		pthread_mutex_unlock(&fr->frMutex());

	} // for(;;)

	return NULL;
} // end thr_popper

}

namespace dbbc {

ioManager::ioManager(FileBufferMgr& fbm,
					fileBlockRequestQueue& fbrq,
					int thrCount):
		fIOMfbMgr(fbm),
		fIOMRequestQueue(fbrq)
{
	pageSize = getpagesize();

	if (thrCount<=0)
		thrCount=1;
	
	if (thrCount > 256)
		thrCount=256;
	
	fConfig = Config::makeConfig();
	fThreadCount=thrCount;
	go();
}

void ioManager::buildOidFileName(const BRM::OID_t oid, char* file_name) {

	if (fFileOp.getFileName(oid, file_name) != WriteEngine::NO_ERROR) {
		file_name[0]=0;
		throw std::runtime_error("fileOp.getFileName failed");
	}
}


BRM::LBID_t ioManager::lbidLookup(BRM::LBID_t lbid,
						   BRM::VER_t verid,
						   bool vbFlag,
						   BRM::OID_t& oid,
							uint32_t& offset)
{
 int rc;

 // do the extent map lookup, possibly looking aside into the VBBM
 rc =  fdbrm.lookup(lbid, verid, vbFlag, oid, offset);

 return rc;
}

int ioManager::createReaders() {
	int realCnt=0;
	for (int idx=0; idx<fThreadCount; idx++){
		int ret = pthread_create(&fThreadArr[realCnt], NULL, thr_popper, this);
 		if (ret!=0)
 			perror("createReaders::pthread_create");
		else
			realCnt++;
	}
	fThreadCount=realCnt;
	return fThreadCount;
}


ioManager::~ioManager()
{
// 	cout << "~ioManager()"<<endl;
	stop();
}

void ioManager::go(void) {
	createReaders();
}


void ioManager::stop() {
	for(int idx=0; idx <fThreadCount; idx++) {
		pthread_detach(fThreadArr[idx]);
	}
}


fileRequest* ioManager::getNextRequest() {
	fileRequest* blk = NULL; /*fIOMRequestQueue.top();*/
	try {
		blk = fIOMRequestQueue.pop();
		return blk;
	} catch (exception& e) {
		cerr << "ioManager::getNextRequest() ERROR " << endl;
	}

	return blk;
	
}

}
// vim:ts=4 sw=4: