ttail/src/ttail_search_files.c

/*
 * Copyright 2017 Yann Weber
 * 
 * This file is part of Ttail.
 * 
 * Ttail is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 * 
 * Ttail 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with Ttail.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "ttail_search_files.h"

int _ttail_search_closest_files(ttail_t* t)
{
	int ret;
	size_t i, prev;
	struct tm **ftm; /* t->logfile_sz len of struct tm[2] */
	char prev_found;
	ret = _ttail_search_closest_files_init(t);
	if(ret)
	{
		return ret;
	}
	/* Storing min & max of each files in ftm and checking that files are 
	 * sorted well */
	ftm = malloc(sizeof(struct tm*) * t->logfile_sz);
	if(!ftm)
	{
		perror("Unable to allocate memory");
		goto _ttail_search_closest_files_alloc_err;
	}
	prev_found = 0;
	prev = 0;
	for(i=0; i<t->logfile_sz; i++)
	{
		if(!t->logfile[i])
		{
			ftm[i] = NULL;
			continue;
		}
		ftm[i] = malloc(sizeof(struct tm)*2);
		if(!ftm[i])
		{
			perror("Unable to allocate memory for time");
			goto _ttail_search_closest_files_alloc_loop_err;
		}
		ret = _ttail_file_minmax(t, i, ftm[i]);
		if(ret < 0)
		{
			fprintf(stderr, "Minmax error\n");
			goto _ttail_search_closest_files_loop_err;
		}
		else if (ret == 1)
		{
			fprintf(stderr, "Warning : unable to find a valid date \
in '%s'\n", t->logfile_name[i]);
			free(ftm[i]);
			ftm[i] = NULL;
			fclose(t->logfile[i]);
			t->logfile[i] = NULL;
			continue;
		}
		if(i && prev_found &&
			ttail_tm_cmp(&(ftm[prev][1]), &(ftm[i][0])) > 0)
		{
			/* files are not sorted */
			fprintf(stderr, "Files do not seems to be sorted. \
File sorting not implemented yet\n");
			goto _ttail_search_closest_files_loop_err;
		}
		prev_found = 1;
		prev = i;
	}
	if(t->flag & TTAIL_FLAG_DATE_MIN)
	{
		ret = _ttail_search_files_binary_search(t, &(t->date_min),
			(const struct tm**)ftm, 1);
		if(ret)
		{
			if(t->verbose > 2)
			{
				fprintf(stderr, "Error while looking for \
date-max\n");
			}
			goto _ttail_search_closest_files_err;
		}
	}
	for(i=0; i<t->logfile_sz; i++)
	{
		if(!t->logfile[i])
		{
			continue;
		}
		if(fseek(t->logfile[i], 0, SEEK_SET) < 0)
		{
			perror("Error setting position in file");
			goto _ttail_search_closest_files_err;
		}
	}
	if(t->flag & TTAIL_FLAG_DATE_MAX)
	{
		ret = _ttail_search_files_binary_search(t, &(t->date_max),
			(const struct tm**)ftm, 0);
		if(ret)
		{
			if(t->verbose > 2)
			{
				fprintf(stderr, "Error while looking for \
date-max\n");
			}
			goto _ttail_search_closest_files_err;
		}
		t->session->file.off_max.off++;
	}
	for(i=0; i<t->logfile_sz; i++)
	{
		if(ftm) { free(ftm[i]); }
	}
	free(ftm);
	return ret;

	goto _ttail_search_closest_files_err;
	_ttail_search_closest_files_err:
	i = t->logfile_sz;
	do
	{
		_ttail_search_closest_files_alloc_loop_err:
		i--;
		_ttail_search_closest_files_loop_err:
		if(ftm[i])
		{
			free(ftm[i]);
		}
	}while(i);
	free(ftm);
	_ttail_search_closest_files_alloc_err:
	return -1;
}

void _ttail_search_print_files(ttail_t* t, int out)
{
	size_t i;
	int fd;
	char buf[8192];
	int r;
	off_t cur_off;
	
	/* if no date_min t->session->file.id == 0 */
	for(i=t->session->file.off_min.id; i<t->logfile_sz; i++)
	{
		if(!t->logfile[i])
		{
			continue;
		}
		fd = fileno(t->logfile[i]);
		if(t->flag & TTAIL_FLAG_DATE_MIN &&
			i==t->session->file.off_min.id)
		{
			if(t->flag & TTAIL_FLAG_DATE_MAX)
			{
				fseek(t->logfile[i],
					t->session->file.off_min.off,
					SEEK_SET);
			}
			else
			{
				lseek(fd, t->session->file.off_min.off,
					SEEK_SET);
			}
		}
		else
		{
			if(t->flag & TTAIL_FLAG_DATE_MAX)
			{
				fseek(t->logfile[i], 0, SEEK_SET);
			}
			else
			{
				lseek(fd, 0, SEEK_SET);
			}
		}
		cur_off = 0;
		while(1)
		{
			if(t->flag & TTAIL_FLAG_DATE_MAX)
			{
				if(i >= t->session->file.off_max.id &&
					cur_off >= t->session->file.off_max.off)
				{
					return;
				}
				if((r = ttail_file_getline(t, i)) < 0)
				{
					break;
				}
				cur_off += r;
				write(out, ttail_file_getline_buf(t),
					strlen(ttail_file_getline_buf(t)));
			}
			else
			{
				r = read(fd, buf, sizeof(buf));
				if(r == -1)
				{
					perror("unable to read file");
					return;
				}
				else if(r == 0)
				{
					break;
				}
				cur_off += r;
				r = write(out, buf, r);
				if(r == -1 || r == 0)
				{
					perror("Unable to write result");
					return;
				}
			}
		}
	}
}

int _ttail_search_files_binary_search(ttail_t* t, const struct tm* in,
	const struct tm** ftm, short min)
{
	int cmin, cmax, ret;
	size_t valid;
	int cmpres;
	off_t tmpoff;
	ttail_files_off_t *files_off;
	size_t *id;
	off_t *off;

	files_off = min?&(t->session->file.off_min):&(t->session->file.off_max);
	id = &(files_off->id),
	off = &(files_off->off);

	*id = *off = 0;
	valid = 0;
	while(*id < t->logfile_sz)
	{
		if(!ftm[*id])
		{
			(*id)++;
			continue;
		}
		valid++;
		cmin = ttail_tm_cmp(&(ftm[*id][0]), in);
		cmax = ttail_tm_cmp(&(ftm[*id][1]), in);
		if(!cmin)
		{
			/* found at the begining of the file */
			return 0;
		}
		else if (cmax == 0)
		{
			/* found at EOF */
			if(min)
			{
				*off = _ttail_from_search_from_end(t, *id, in);
				if(*off < 0)
				{
					*off = 0;
					return -1;
				}
			}
			else
			{
				*off = t->session->file.file_sz[*id];
			}
			return 0;
		}
		else if(cmin > 0)
		{
			/* found at start of file */
			off = 0;
			return 0;
		}
		else if(cmax > 0)
		{
			/* somewhere in current file */
			ret = _ttail_search_file_binary_search(t, in, ftm, min);
			if(ret)
			{
				if(t->verbose > 2)
				{
					fprintf(stderr, "Error while \
running binary search algorithm in '%s'\n", t->logfile_name[*id]);
				}
				*id = 0;
				return ret;
			}
			/* searching for equivalent */
			tmpoff = *off;
			while(1)
			{
				if(fseek(t->logfile[*id], tmpoff, SEEK_SET) < 0)
				{
					return -1;
				}
				tmpoff = min?
					_ttail_file_start_line(t->logfile[*id]):
					_ttail_file_next_line(t->logfile[*id]);
				if(tmpoff < 0)
				{
					break;
				}
				cmpres=0;
				ret = _ttail_file_cur_cmp(t, *id, in, &cmpres);
				if((min && cmpres < 0) || (!min && cmpres > 0))
				{
					break;
				}
				*off = tmpoff;
				if(min)
				{
					tmpoff--;
				}
			}
			return 0;
		}
		else if(*id == t->logfile_sz - 1 && cmax < 0)
		{
			*off = t->session->file.file_sz[*id];
			return 0;
		}
		(*id)++;
	}
	if(!valid)
	{
		fprintf(stderr, "No files to scan\n");
		return 0;
	}
	/* the answer is somewhere in *id file */
	*off = _ttail_from_search_from_end(t, *id, in);
	return 0;
}

inline int _ttail_search_file_binary_search(ttail_t* t, const struct tm* in,
	const struct tm** ftm, short min)
{
	off_t cur, sz, d, prev, tmp;
	int ret, cmpres;
	ttail_files_off_t *files_off;
	size_t id;
	off_t *off;

	files_off = min?&(t->session->file.off_min):&(t->session->file.off_max);
	id = files_off->id,
	off = &(files_off->off);
	
	sz = t->session->file.file_sz[id];
	d = cur = sz / 2;
	prev = 0;
	cmpres = 0;
	while(1)
	{
		if(fseek(t->logfile[id], cur, SEEK_SET) < 0)
		{
			perror("Unable to move in the file");
			return -1;
		}
		if(cur > prev)
		{
			cur = _ttail_file_next_line(t->logfile[id]);
			if(cur < 0)
			{
				/* not sure errno is really set */
				perror("Error searching previous line");
				return -1;
			}
		}
		else
		{
			cur = _ttail_file_start_line(t->logfile[id]);
			if(cur < 0)
			{
				/* not sure errno is really set */
				perror("Error searching previous line");
				return -1;
			}
		}
		if(cur == prev)
		{
			*off = cur;
			return 0;
		}
		prev = cur;
		ret = _ttail_file_cur_cmp(t, id, in, &cmpres);
		if(ret < 0)
		{
			if(t->verbose > 2)
			{
				fprintf(stderr, "Error comparing a logline \
to a date directly from a file\n");
			}
			return -1;
		}
		else if(cmpres == 0)
		{
			*off = cur;
			break;
		}
		else if(cmpres < 0)
		{
			tmp = _ttail_file_next_line(t->logfile[id]);
			ret = _ttail_file_cur_cmp(t, id, in, &cmpres);
			if(cmpres >=0)
			{
				*off = tmp;
				break;
			}
			d/=2;
			cur += d;
			cur %= t->session->file.file_sz[id];
		}
		else
		{
			d/=2;
			cur -= d;
			if(cur < 0)
			{
				cur = 0;
			}
		}
	}
	return 0;
}

int _ttail_search_closest_files_init(ttail_t* t)
{
	struct stat stat;
	FILE *fp;
	int fd;
	size_t i;
	off_t *file_sz;

	t->session = (ttail_search_t*)malloc(sizeof(ttail_search_file_t));
	if(!t->session)
	{
		perror("Unable to allocate memory for search session");
		goto _ttail_search_closest_files_alloc_session_err;
	}
	memset(t->session, 0, sizeof(ttail_search_file_t));

	file_sz = malloc(sizeof(off_t)*t->logfile_sz);
	if(!file_sz)
	{
		perror("Unable to allocate memory for file sizes");
		goto _ttail_search_closest_files_alloc_err;
	}
	t->session->file.file_sz = file_sz;
	#ifdef HUGEFILE
	t->session->file.sz_div = 0;
	#endif

	for(i=0;i<t->logfile_sz;i++)
	{
		fp = t->logfile[i];
		if(!fp)
		{
			file_sz[i] = 0;
			continue;
		}
		if((fd = fileno(fp)) < 0)
		{
			perror("Unable to get fp");
			goto _ttail_search_closest_files_err;
		}
		if(fstat(fileno(fp), &stat))
		{
			perror("Unable to get file size");
			goto _ttail_search_closest_files_err;
		}
		file_sz[i] = stat.st_size;
	}
	/* we got all real size, determining if we need a divisor */
	/*
	 * not implemented
	 */
	if(_ttail_search_closest_files_set_fsizes(t))
	{
		goto _ttail_search_closest_files_err;
	}

	t->session->file.buf_sz = 128;
	t->session->file.buf = malloc(t->session->file.buf_sz);
	if(!t->session->file.buf)
	{
		goto _ttail_search_closest_files_err;
	}

	return 0;

	_ttail_search_closest_files_err:
	free(file_sz);
	t->session->file.file_sz = NULL;
	_ttail_search_closest_files_alloc_err:
	free(t->session);
	_ttail_search_closest_files_alloc_session_err:
	return -1;
}

int _ttail_search_closest_files_set_fsizes(ttail_t* t)
{
	size_t i;
	off_t *vfile, *vsz;
	vfile = malloc(sizeof(off_t)*t->logfile_sz);
	if(!vfile)
	{
		perror("Unable to allocate memory for file size sum");
		return -1;
	}
	t->session->file.vfile = vfile;
	vsz = &(t->session->file.vsz);
	*vsz = 0;
	for(i=0; i<t->logfile_sz;i++)
	{
		vfile[i] = *vsz;
		#ifdef HUGEFILE
		*vsz += t->session->file.file_sz[i] >> t->session->file.sz_div;
		#else
		*vsz += t->session->file.file_sz[i];
		#endif
	}
	t->session->file.vpos = 0;
	return 0;
}

inline int _ttail_file_minmax(ttail_t* t, size_t id, struct tm tm[2])
{
	FILE *fp;
	long cur;
	memset(tm, 0, sizeof(struct tm)*2);
	fp = t->logfile[id];
	if(!fp)
	{
		return 1;
	}
	if(fseek(fp, 0, SEEK_SET) < 0)
	{
		perror("Unable to manipulate fp");
		return -1;
	}
	while(1)
	{
		if(ttail_file_getline(t, id) < 0)
		{
			return 1;
		}
		if(!ttail_logline2date(t, ttail_file_getline_buf(t), tm))
		{
			break;
		}
	}
	if(fseek(fp, -1, SEEK_END) < 0)
	{
		perror("Unable to manipulate fp");
		return -1;
	}
	while(1)
	{
		if((cur = _ttail_file_start_line(fp)) < 0)
		{
			return -1;
		}
		if(ttail_file_getline(t, id) < 0)
		{
			return 1;
		}
		if(!ttail_logline2date(t, ttail_file_getline_buf(t), tm+1))
		{
			break;
		}
		if(!cur)
		{
			return 1;
		}
		if(fseek(fp, cur-1, SEEK_SET) < 0)
		{
			perror("Unable to manipulate fp");
			return -1;
		}
	}
	return 0;
}

int _ttail_file_reopen(ttail_t* t, size_t id)
{
	if(t->logfile[id])
	{
		fclose(t->logfile[id]);
	}
	t->logfile[id] = fopen(t->logfile_name[id], "r");
	if(!t->logfile[id] && t->verbose > 2)
	{
		fprintf(stderr, "Unable to reopen '%s'\n",
			t->logfile_name[id]);
	}
	return t->logfile[id]?0:-1;
}

inline long _ttail_file_next_line(FILE* f)
{
	ssize_t s;
	size_t r;
	char *buff;
	long res;
	int c;
	
	r=0;
	buff = NULL;
	s = getline(&buff, &r, f);
	if(s < 0)
	{
		goto _ttail_file_next_line_err;
	}
	while(1)
	{
		c = getc(f);
		if(c == EOF)
		{
			return 0;
		}
		else if(c!='\n')
		{
			if(fseek(f, -1, SEEK_CUR)<0)
			{
				perror("Unable to set position in file");
				goto _ttail_file_next_line_err;
			}
			break;
		}
	}

	res = ftell(f);
	free(buff);
	return res;

	_ttail_file_next_line_err:
	free(buff);
	return -1;
}

inline long _ttail_file_start_line(FILE* f)
{
	#define _STARTLN_BUFFLEN 32
	long res; /* function result */
	long read_beg, cur, last, start;
	int read_sz;
	int c;

	if((start = ftell(f)) < 0)
	{
		perror("Unable to get position in file");
		return -1;
	}
	res = 0;
	read_beg = start;
	while(!res && start)
	{
		if(fseek(f, read_beg, SEEK_SET) < 0)
		{
			perror("Unable to set position in file");
			return -1;
		}
		start = read_beg;
		read_sz = start <= _STARTLN_BUFFLEN?start:_STARTLN_BUFFLEN;
		read_beg = start - read_sz;
		if(fseek(f, read_beg, SEEK_SET) < 0)
		{
			perror("Unable to set position in file");
			return -1;
		}
		last = -1; /* last pos we saw a '\n' */
		cur = read_beg;
		while(cur <= start)
		{
			c = getc(f);
			if(c == EOF)
			{
				if(!res)
				{
					return 0;
				}
				break;
			}
			else if (c =='\n')
			{
				last = cur;
			}
			else if(last >= 0)
			{
				res = cur;
				last = -1;
			}
			cur++;
		}
		if(!read_beg)
		{
			break;
		}
	}
	if(fseek(f, res, SEEK_SET) < 0)
	{
		perror("Unable to set position in file");
		return -1;
	}
	return res;
}

inline off_t _ttail_from_search_from_end(ttail_t* t , size_t id , 
	const struct tm* tm)
{
	FILE *f;
	struct tm curtm;
	off_t last;
	int ret, cmpret;
	off_t result;

	result = -1;
	f = t->logfile[id];
	if(fseek(f, -1, SEEK_END) < 0)
	{
		return -1;
	}
	while(1)
	{
		last = _ttail_file_start_line(f);
		if(last < 0)
		{
			break;
		}
		if(ttail_file_getline(t, id) < 0)
		{
			break;
		}
		ret = ttail_logline2date(t, ttail_file_getline_buf(t), &curtm);
		if(ret < 0)
		{
			break;
		}
		cmpret = ttail_tm_cmp(&curtm, tm);
		if(!ret)
		{
			if(cmpret >= 0)
			{
				/* found but continue to search the first one*/
				result = last;
			}
			else
			{
				if(cmpret < 0 && result < 0)
				{
					result = last;
				}
				break;
			}
		}
		if(last == 0)
		{
			/* considere the begining of the file as the answer */
			return 0;
		}
		if(fseek(f, last-1, SEEK_SET))
		{
			return -1;
		}
	}
	return result;
}

inline int _ttail_file_off_cmp(ttail_t* t, size_t id, off_t off,
	const struct tm* tm, int *res)
{
	if(fseek(t->logfile[id], off, SEEK_SET))
	{
		perror("Unable to set position in file");
		return -1;
	}
	if(ttail_file_getline(t, id) < 0)
	{
		perror("Unable to read a line from file");
		return -1;
	}
	return _ttail_file_cur_cmp(t, id, tm, res);
}
inline int _ttail_file_cur_cmp(ttail_t* t, size_t id, const struct tm* tm ,
	int* res)
{
	int ret;
	struct tm ctm;
	if(ttail_file_getline(t, id) < 0)
	{
		return -1;
	}
	ret = ttail_logline2date(t, ttail_file_getline_buf(t), &ctm);
	if(ret)
	{
		return -1;
	}
	else if(ret == 1)
	{
		return 1;
	}
	*res = ttail_tm_cmp(&ctm, tm);
	return 0;

}

void _ttail_search_file_free(ttail_t* t)
{
	if(!t->session)
	{
		return;
	}
	if(t->session->file.buf)
	{
		free(t->session->file.buf);
	}
	if(t->session->file.file_sz)
	{
		free(t->session->file.file_sz);
	}
	if(t->session->file.vfile)
	{
		free(t->session->file.vfile);
	}
	free(t->session);
}