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#include <matcher.h>
#include <logger.h>
#include <utils.h>
#include <exceptions.h>
#include <sys/time.h>
#include <regex.h>
#include <ctime>
#include <cassert>
#include <sstream>
#include <vector>
namespace newsbeuter {
matchable::matchable() { }
matchable::~matchable() { }
matcher::matcher() { }
matcher::matcher(const std::string& expr) : exp(expr) {
parse(expr);
}
const std::string& matcher::get_expression() {
return exp;
}
bool matcher::parse(const std::string& expr) {
struct timeval tv1, tv2;
gettimeofday(&tv1, NULL);
errmsg = "";
bool b = p.parse_string(expr);
if (!b) {
errmsg = utils::wstr2str(p.get_error());
}
gettimeofday(&tv2, NULL);
unsigned long diff = (((tv2.tv_sec - tv1.tv_sec) * 1000000) + tv2.tv_usec) - tv1.tv_usec;
LOG(LOG_DEBUG, "matcher::parse: parsing `%s' took %lu µs (success = %d)", expr.c_str(), diff, b ? 1 : 0);
return b;
}
bool matcher::matches(matchable* item) {
/*
* with this method, every class that is derived from matchable can be
* matched against a filter expression that was previously passed to the
* class with the parse() method.
*
* This makes it easy to use the matcher virtually everywhere, since C++
* allows multiple inheritance (i.e. deriving from matchable can even be
* used in class hierarchies), and deriving from matchable means that you
* only have to implement two methods has_attribute() and get_attribute().
*
* The whole matching code is speed-critical, as the matching happens on a
* lot of different occassions, and slow matching can be easily measured
* (and felt by the user) on slow computers with a lot of items to match.
*/
bool retval = false;
if (item) {
scope_measure m1("matcher::matches");
retval = matches_r(p.get_root(), item);
}
return retval;
}
bool matcher::matchop_lt(expression * e, matchable * item) {
if (!item->has_attribute(e->name))
throw matcherexception(matcherexception::ATTRIB_UNAVAIL, e->name);
std::istringstream islit(e->literal);
std::istringstream isatt(item->get_attribute(e->name));
int ilit, iatt;
islit >> ilit;
isatt >> iatt;
return iatt < ilit;
}
bool matcher::matchop_between(expression * e, matchable * item) {
if (!item->has_attribute(e->name))
throw matcherexception(matcherexception::ATTRIB_UNAVAIL, e->name);
std::vector<std::string> lit = utils::tokenize(e->literal, ":");
std::istringstream isatt(item->get_attribute(e->name));
int att;
isatt >> att;
if (lit.size() < 2)
return false;
std::istringstream is1(lit[0]), is2(lit[1]);
int i1, i2;
is1 >> i1;
is2 >> i2;
if (i1 > i2) {
int tmp = i1;
i1 = i2;
i2 = tmp;
}
return (att >= i1 && att <= i2);
}
bool matcher::matchop_gt(expression * e, matchable * item) {
if (!item->has_attribute(e->name))
throw matcherexception(matcherexception::ATTRIB_UNAVAIL, e->name);
std::istringstream islit(e->literal);
std::istringstream isatt(item->get_attribute(e->name));
int ilit, iatt;
islit >> ilit;
isatt >> iatt;
return iatt > ilit;
}
bool matcher::matchop_rxeq(expression * e, matchable * item) {
if (!item->has_attribute(e->name))
throw matcherexception(matcherexception::ATTRIB_UNAVAIL, e->name);
if (!e->regex) {
e->regex = new regex_t;
int err;
if ((err = regcomp(e->regex, e->literal.c_str(), REG_EXTENDED | REG_ICASE | REG_NOSUB)) != 0) {
char buf[1024];
regerror(err, e->regex, buf, sizeof(buf));
throw matcherexception(matcherexception::INVALID_REGEX, e->literal, buf);
}
}
if (regexec(e->regex, item->get_attribute(e->name).c_str(), 0, NULL, 0)==0)
return true;
return false;
}
bool matcher::matchop_cont(expression * e, matchable * item) {
if (!item->has_attribute(e->name))
throw matcherexception(matcherexception::ATTRIB_UNAVAIL, e->name);
std::vector<std::string> elements = utils::tokenize(item->get_attribute(e->name), " ");
std::string literal = e->literal;
for (auto elem : elements) {
if (literal == elem) {
return true;
}
}
return false;
}
bool matcher::matchop_eq(expression * e, matchable * item) {
if (!item->has_attribute(e->name)) {
LOG(LOG_WARN, "matcher::matches_r: attribute %s not available", e->name.c_str());
throw matcherexception(matcherexception::ATTRIB_UNAVAIL, e->name);
}
return (item->get_attribute(e->name)==e->literal);
}
bool matcher::matches_r(expression * e, matchable * item) {
if (e) {
switch (e->op) {
/* the operator "and" and "or" simply connect two different subexpressions */
case LOGOP_AND:
return matches_r(e->l, item) && matches_r(e->r, item); // short-circuit evaulation in C -> short circuit evaluation in the filter language
case LOGOP_OR:
return matches_r(e->l, item) || matches_r(e->r, item); // same here
/* while the other operator connect an attribute with a value */
case MATCHOP_EQ:
return matchop_eq(e, item);
case MATCHOP_NE:
return !matchop_eq(e, item);
case MATCHOP_LT:
return matchop_lt(e, item);
case MATCHOP_BETWEEN:
return matchop_between(e, item);
case MATCHOP_GT:
return matchop_gt(e, item);
case MATCHOP_LE:
return !matchop_gt(e, item);
case MATCHOP_GE:
return !matchop_lt(e, item);
case MATCHOP_RXEQ:
return matchop_rxeq(e, item);
case MATCHOP_RXNE:
return !matchop_rxeq(e, item);
case MATCHOP_CONTAINS:
return matchop_cont(e, item);
case MATCHOP_CONTAINSNOT:
return !matchop_cont(e, item);
}
return false;
} else {
return true; // shouldn't happen
}
}
const std::string& matcher::get_parse_error() {
return errmsg;
}
}
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