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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) {
parse(expr);
}
bool matcher::parse(const std::string& expr) {
struct timeval tv1, tv2;
gettimeofday(&tv1, NULL);
bool b = p.parse_string(expr);
gettimeofday(&tv2, NULL);
unsigned long diff = (((tv2.tv_sec - tv1.tv_sec) * 1000000) + tv2.tv_usec) - tv1.tv_usec;
GetLogger().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) { struct timeval tv1, tv2;
gettimeofday(&tv1, NULL);
retval = matches_r(p.get_root(), item);
gettimeofday(&tv2, NULL);
unsigned long diff = (((tv2.tv_sec - tv1.tv_sec) * 1000000) + tv2.tv_usec) - tv1.tv_usec;
GetLogger().log(LOG_DEBUG, "matcher::matches matching took %lu µs", diff);
}
return retval;
}
bool matcher::matches_r(expression * e, matchable * item) {
if (e) {
bool retval;
switch (e->op) {
/* the operator "and" and "or" simply connect two different subexpressions */
case LOGOP_AND:
retval = matches_r(e->l, item);
retval = retval && matches_r(e->r, item); // short-circuit evaulation in C -> short circuit evaluation in the filter language
break;
case LOGOP_OR:
retval = matches_r(e->l, item);
retval = retval || matches_r(e->r, item); // same here
break;
/* while the other operator connect an attribute with a value */
case MATCHOP_EQ:
if (item->has_attribute(e->name))
retval = (item->get_attribute(e->name)==e->literal);
else {
GetLogger().log(LOG_WARN, "matcher::matches_r: attribute %s not available", e->name.c_str());
throw matcherexception(matcherexception::ATTRIB_UNAVAIL, e->name);
}
break;
case MATCHOP_NE:
if (item->has_attribute(e->name))
retval = (item->get_attribute(e->name)!=e->literal);
else {
GetLogger().log(LOG_WARN, "matcher::matches_r: attribute %s not available", e->name.c_str());
throw matcherexception(matcherexception::ATTRIB_UNAVAIL, e->name);
}
break;
case MATCHOP_LT: {
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;
}
break;
case MATCHOP_GT: {
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;
}
break;
case MATCHOP_LE: {
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;
}
break;
case MATCHOP_GE: {
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;
}
break;
case MATCHOP_RXEQ: {
if (!item->has_attribute(e->name))
throw matcherexception(matcherexception::ATTRIB_UNAVAIL, e->name);
if (!e->regex) {
e->regex = new regex_t;
regcomp(e->regex, e->literal.c_str(), REG_EXTENDED | REG_ICASE | REG_NOSUB); // TODO: see below
}
if (regexec(e->regex, item->get_attribute(e->name).c_str(), 0, NULL, 0)==0)
retval = true;
else
retval = false;
}
break;
case MATCHOP_RXNE: {
if (!item->has_attribute(e->name))
throw matcherexception(matcherexception::ATTRIB_UNAVAIL, e->name);
if (!e->regex) {
e->regex = new regex_t;
regcomp(e->regex, e->literal.c_str(), REG_EXTENDED | REG_ICASE | REG_NOSUB); // TODO: throw error when compilation fails
}
GetLogger().log(LOG_DEBUG, "matchop_rxne: %s !~ %s ?", item->get_attribute(e->name).c_str(), e->literal.c_str());
if (regexec(e->regex, item->get_attribute(e->name).c_str(), 0, NULL, 0)==0) {
GetLogger().log(LOG_DEBUG, "matchop_rxne: yes");
retval = false;
} else {
GetLogger().log(LOG_DEBUG, "matchop_rxne: no");
retval = true;
}
}
break;
case MATCHOP_CONTAINS: {
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;
retval = false;
for (std::vector<std::string>::iterator it=elements.begin();it!=elements.end();++it) {
if (literal == *it) {
retval = true;
break;
}
}
}
break;
case MATCHOP_CONTAINSNOT: {
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;
retval = true;
for (std::vector<std::string>::iterator it=elements.begin();it!=elements.end();++it) {
if (literal == *it) {
retval = false;
break;
}
}
}
break;
default:
GetLogger().log(LOG_ERROR, "matcher::matches_r: invalid operator %d", e->op);
assert(false); // that's an error condition
}
return retval;
} else {
return true; // shouldn't happen
}
}
}
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