#ifndef lint
static char rcsid[] = "@(#$Id: wasastringtoquery.cpp,v 1.1 2006-11-30 18:12:16 dockes Exp $ (C) 2006 J.F.Dockes";
#endif
/*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the
* Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifndef TEST_STRINGTOQUERY
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <regex.h>
#include "wasastringtoquery.h"
WasaQuery::~WasaQuery()
{
for (vector<WasaQuery*>::iterator it = m_subs.begin();
it != m_subs.end(); it++) {
delete *it;
}
m_subs.clear();
}
void WasaQuery::describe(string &desc) const
{
desc += "(";
switch (m_op) {
case OP_NULL:
desc += "NULL";
break;
case OP_LEAF:
desc += m_fieldspec.empty() ?
m_value : m_fieldspec + ":" + m_value;
break;
case OP_EXCL:
desc += string("NOT (" ) + m_value + ") ";
break;
case OP_OR:
case OP_AND:
for (vector<WasaQuery *>::const_iterator it = m_subs.begin();
it != m_subs.end(); it++) {
(*it)->describe(desc);
vector<WasaQuery *>::const_iterator it1 = it;
it1++;
if (it1 != m_subs.end())
desc += m_op == OP_OR ? "OR ": "AND ";
}
break;
}
desc += ") ";
}
// The string query parser code:
/* Shamelessly lifted from Beagle:
* This is our regular Expression Pattern:
* we expect something like this:
* -key:"Value String"
* key:Value
* or
* Value
([+-]?) # Required or Prohibited (optional)
(\w+:)? # Key (optional)
( # Query Text
(\"([^\"]*)\"?)# quoted
| # or
([^\s\"]+) # unquoted
)
";
*/
/* The master regular expression used to parse a query string
* Sub-expressions in parenthesis are numbered from 1. Each opening
* parenthesis increases the index, but we're not interested in all
*/
static const char * parserExpr =
"([oO][rR])" //1 OR is a special word
"|"
"(" //2
"([+-])?" //3 Force or exclude indicator
"(" //4
"([[:alpha:]][[:alnum:]]+)" //5 Field spec: "fieldname:"
":)?"
"(" //6
"(\"" //7
"([^\"]+)" //8 "A quoted term"
"\")"
"|"
"([^[:space:]]+)" //9 ANormalTerm
")"
")"
;
// For debugging the parser. But see also NMATCH
static const char *matchNames[] = {
/*0*/ "",
/*1*/ "OR",
/*2*/ "",
/*3*/ "+-",
/*4*/ "",
/*5*/ "FIELD",
/*6*/ "",
/*7*/ "",
/*8*/ "QUOTEDTERM",
/*9*/ "TERM",
};
#define NMATCH (sizeof(matchNames) / sizeof(char *))
// Symbolic names for the interesting submatch indices
enum SbMatchIdx {SMI_OR=1, SMI_PM=3, SMI_FIELD=5, SMI_QUOTED=8, SMI_TERM=9};
static const int maxmatchlen = 1024;
static const int errbuflen = 300;
class StringToWasaQuery::Internal {
public:
Internal()
: m_rxneedsfree(false)
{}
~Internal()
{
if (m_rxneedsfree)
regfree(&m_rx);
}
bool StringToWasaQuery::Internal::checkSubMatch(int i, char *match,
string& reason)
{
if (i < 0 || i >= int(NMATCH) || m_pmatch[i].rm_so == -1)
return false;
if (m_pmatch[i].rm_eo - m_pmatch[i].rm_so <= 0) {
// weird and fatal
reason = "Internal regular expression handling error";
return false;
}
memcpy(match, m_cp + m_pmatch[i].rm_so,
m_pmatch[i].rm_eo - m_pmatch[i].rm_so);
match[m_pmatch[i].rm_eo - m_pmatch[i].rm_so] = 0;
return true;
}
WasaQuery *stringToQuery(const string& str, string& reason);
friend class StringToWasaQuery;
private:
const char *m_cp;
regex_t m_rx;
bool m_rxneedsfree;
regmatch_t m_pmatch[NMATCH];
};
StringToWasaQuery::StringToWasaQuery()
: internal(new Internal)
{
}
StringToWasaQuery::~StringToWasaQuery()
{
delete internal;
}
WasaQuery *
StringToWasaQuery::stringToQuery(const string& str, string& reason)
{
return internal ? internal->stringToQuery(str, reason) : 0;
}
WasaQuery *
StringToWasaQuery::Internal::stringToQuery(const string& str, string& reason)
{
if (m_rxneedsfree)
regfree(&m_rx);
char errbuf[errbuflen+1];
int errcode;
if ((errcode = regcomp(&m_rx, parserExpr, REG_EXTENDED)) != 0) {
regerror(errcode, &m_rx, errbuf, errbuflen);
reason = errbuf;
return 0;
}
m_rxneedsfree = true;
const char *cpe;
m_cp = str.c_str();
cpe = str.c_str() + str.length();
WasaQuery *query = new WasaQuery;
query->m_op = WasaQuery::OP_AND;
WasaQuery *orClause = 0;
bool prev_or = false;
// Loop on repeated regexp matches on the main string.
for (int loop = 0;;loop++) {
if ((errcode = regexec(&m_rx, m_cp, NMATCH, m_pmatch, 0))) {
regerror(errcode, &m_rx, errbuf, errbuflen);
reason = errbuf;
return 0;
}
if (m_pmatch[0].rm_eo <= 0) {
// weird and fatal
reason = "Internal regular expression handling error";
return 0;
}
#if 0
if (loop) printf("Next part:\n");
for (i = 0; i < NMATCH; i++) {
if (m_pmatch[i].rm_so == -1) continue;
char match[maxmatchlen+1];
memcpy(match, m_cp + m_pmatch[i].rm_so,
m_pmatch[i].rm_eo - m_pmatch[i].rm_so);
match[m_pmatch[i].rm_eo - m_pmatch[i].rm_so] = 0;
if (matchNames[i][0])
printf("%10s: [%s] (%d->%d)\n", matchNames[i], match,
(int)m_pmatch[i].rm_so, (int)m_pmatch[i].rm_eo);
}
#endif
char match[maxmatchlen+1];
if (checkSubMatch(SMI_OR, match, reason)) {
if (prev_or) {
// Bad syntax
reason = "Bad syntax: consecutive OR";
return 0;
}
if (orClause == 0) {
// Fist OR seen: start OR subclause.
if ((orClause = new WasaQuery()) == 0) {
reason = "Out of memory";
return 0;
}
orClause->m_op = WasaQuery::OP_OR;
}
// We need to transfer the previous query from the main vector
// to the OR subquery
if (!query->m_subs.empty()) {
orClause->m_subs.push_back(query->m_subs.back());
query->m_subs.pop_back();
}
prev_or = true;
} else {
WasaQuery *nclause = new WasaQuery;
if (nclause == 0) {
reason = "Out of memory";
return 0;
}
// Check for quoted or unquoted value
if (checkSubMatch(SMI_QUOTED, match, reason)) {
nclause->m_value = match;
} else if (checkSubMatch(SMI_TERM, match, reason)) {
nclause->m_value = match;
}
if (nclause->m_value.empty()) {
// Isolated +- or fieldname: without a value. Ignore until
// told otherwise.
delete nclause;
return 0;
}
// +- indicator ?
if (checkSubMatch(SMI_PM, match, reason) && match[0] == '-') {
nclause->m_op = WasaQuery::OP_EXCL;
} else {
nclause->m_op = WasaQuery::OP_LEAF;
}
// Field indicator ?
if (checkSubMatch(SMI_FIELD, match, reason)) {
nclause->m_fieldspec = match;
}
if (prev_or) {
// We're in an OR subquery, add new subquery
orClause->m_subs.push_back(nclause);
} else {
if (orClause) {
// Getting out of OR. Add the OR subquery to the main one
query->m_subs.push_back(orClause);
orClause = 0;
}
// Add new subquery to main one.
query->m_subs.push_back(nclause);
}
prev_or = false;
}
// Advance current string position. We checked earlier that
// the increment is strictly positive, so we won't loop
// forever
m_cp += m_pmatch[0].rm_eo;
if (m_cp >= cpe)
break;
}
regfree(&m_rx);
m_rxneedsfree = false;
return query;
}
#else // TEST
#include <stdio.h>
#include "wasastringtoquery.h"
static char *thisprog;
int main(int argc, char **argv)
{
thisprog = argv[0];
argc--; argv++;
if (argc != 1) {
fprintf(stderr, "need one arg\n");
exit(1);
}
const string str = *argv++;argc--;
string reason;
StringToWasaQuery qparser;
WasaQuery *q = qparser.stringToQuery(str, reason);
if (q == 0) {
fprintf(stderr, "stringToQuery failed: %s\n", reason.c_str());
exit(1);
}
string desc;
q->describe(desc);
printf("%s\n", desc.c_str());
exit(0);
}
#endif // TEST_STRINGTOQUERY