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wasastringtoquery.cpp    460 lines (414 with data), 13.0 kB

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/* Copyright (C) 2006 J.F.Dockes
* 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_WASASTRINGTOQUERY
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <regex.h>
#include "wasastringtoquery.h"
// #define DEB_WASASTRINGTOQ 1
#ifdef DEB_WASASTRINGTOQ
#define DPRINT(X) fprintf X
#define DUMPQ(Q) {string D;Q->describe(D);fprintf(stderr, "%s\n", D.c_str());}
#else
#define DPRINT(X)
#define DUMPQ(Q)
#endif
WasaQuery::~WasaQuery()
{
for (vector<WasaQuery*>::iterator it = m_subs.begin();
it != m_subs.end(); it++) {
delete *it;
}
m_subs.clear();
}
static const char* reltosrel(WasaQuery::Rel rel)
{
switch (rel) {
case WasaQuery::REL_EQUALS: return "=";
case WasaQuery::REL_CONTAINS: return ":";
case WasaQuery::REL_LT: return "<";
case WasaQuery::REL_LTE: return "<=";
case WasaQuery::REL_GT: return ">";
case WasaQuery::REL_GTE: return ">=";
default: return "?";
}
}
void WasaQuery::describe(string &desc) const
{
desc += "(";
string fieldspec = m_fieldspec.empty() ? string() : m_fieldspec +
reltosrel(m_rel);
switch (m_op) {
case OP_NULL:
desc += "NULL";
break;
case OP_LEAF:
desc += fieldspec + m_value;
break;
case OP_EXCL:
desc += string("NOT (" ) + fieldspec + 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;
}
if (desc[desc.length() - 1] == ' ')
desc.erase(desc.length() - 1);
desc += ")";
if (m_modifiers != 0) {
if (m_modifiers & WQM_BOOST) desc += "BOOST|";
if (m_modifiers & WQM_CASESENS) desc += "CASESENS|";
if (m_modifiers & WQM_DIACSENS) desc += "DIACSENS|";
if (m_modifiers & WQM_NOSTEM) desc += "NOSTEM|";
if (m_modifiers & WQM_BOOST) desc += "BOOST|";
if (m_modifiers & WQM_PROX) desc += "PROX|";
if (m_modifiers & WQM_SLOPPY) desc += "SLOPPY|";
if (m_modifiers & WQM_WORDS) desc += "WORDS|";
if (m_modifiers & WQM_PHRASESLACK) desc += "PHRASESLACK|";
if (m_modifiers & WQM_REGEX) desc += "REGEX|";
if (m_modifiers & WQM_FUZZY) desc += "FUZZY|";
if (desc.length() > 0 && desc[desc.length()-1] == '|')
desc = desc.substr(0, desc.length()-1);
}
desc += " ";
}
// The string query parser code:
/* Shamelessly lifted from Beagle:
* This is our regular Expression Pattern:
* we expect something like this:
* -key:"Value String"modifiers
* key:Value
* or
* Value
*/
/* 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 =
"(OR|\\|\\|)[[:space:]]*" //1 OR,||
"|"
"(AND|&&)[[:space:]]*" // 2 AND,&& (ignored, default)
"|"
"(" //3
"([+-])?" //4 Force or exclude indicator
"(" //5
"([[:alpha:]][[:alnum:]:]*)" //6 Field spec: ie: "dc:title:letitre"
"[[:space:]]*"
"(:|=|<|>|<=|>=)" //7 Relation
"[[:space:]]*)?"
"(" //8
"(\"" //9
"([^\"]+)" //10 "A quoted term"
"\")"
"([a-zA-Z0-9]*)" //11 modifiers
"|"
"([^[:space:]\"]+)" //12 ANormalTerm
")"
")[[:space:]]*"
;
// For debugging the parser. But see also NMATCH
static const char *matchNames[] = {
/* 0*/ "",
/* 1*/ "OR",
/* 2*/ "AND",
/* 3*/ "",
/* 4*/ "+-",
/* 5*/ "",
/* 6*/ "FIELD",
/* 7*/ "RELATION",
/* 8*/ "",
/* 9*/ "",
/*10*/ "QUOTEDTERM",
/*11*/ "MODIIFIERS",
/*12*/ "TERM",
};
#define NMATCH (sizeof(matchNames) / sizeof(char *))
// Symbolic names for the interesting submatch indices
enum SbMatchIdx {SMI_OR=1, SMI_AND=2, SMI_PM=4, SMI_FIELD=6, SMI_REL=7,
SMI_QUOTED=10, SMI_MODIF=11, SMI_TERM=12};
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 checkSubMatch(int i, char *match, string& reason)
{
if (i < 0 || i >= int(NMATCH) || m_pmatch[i].rm_so == -1) {
//DPRINT((stderr, "checkSubMatch: no match: i %d rm_so %d\n",
//i, m_pmatch[i].rm_so));
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;
}
//DPRINT((stderr, "checkSubMatch: so %d eo %d\n", m_pmatch[i].rm_so,
//m_pmatch[i].rm_eo));
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 *orChain = 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;
}
#ifdef DEB_WASASTRINGTOQ
DPRINT((stderr, "Next part:\n"));
for (unsigned int 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])
DPRINT((stderr, "%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 (orChain == 0) {
// Fist OR seen: start OR subclause.
if ((orChain = new WasaQuery()) == 0) {
reason = "Out of memory";
return 0;
}
orChain->m_op = WasaQuery::OP_OR;
}
// For the first OR, we need to transfer the previous
// query from the main vector to the OR subquery
if (orChain->m_subs.empty() && !query->m_subs.empty()) {
orChain->m_subs.push_back(query->m_subs.back());
query->m_subs.pop_back();
}
prev_or = true;
} else if (checkSubMatch(SMI_AND, match, reason)) {
// Do nothing, AND is the default. We might want to check for
// errors like consecutive ANDs, or OR AND
} 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.
DPRINT((stderr, "Clause with empty value, skipping\n"));
delete nclause;
goto nextfield;
}
if (checkSubMatch(SMI_MODIF, match, reason)) {
DPRINT((stderr, "Got modifiers: [%s]\n", match));
unsigned int mods = 0;
for (unsigned int i = 0; i < strlen(match); i++) {
switch (match[i]) {
case 'b': mods |= WasaQuery::WQM_BOOST; break;
case 'c': break;
case 'C': mods |= WasaQuery::WQM_CASESENS; break;
case 'd': break;
case 'D': mods |= WasaQuery::WQM_DIACSENS; break;
case 'e': mods |= WasaQuery::WQM_CASESENS | WasaQuery::WQM_DIACSENS | WasaQuery::WQM_NOSTEM; break;
case 'f': mods |= WasaQuery::WQM_FUZZY; break;
case 'l': mods |= WasaQuery::WQM_NOSTEM; break;
case 'L': break;
case 'o': mods |= WasaQuery::WQM_PHRASESLACK; break;
case 'p': mods |= WasaQuery::WQM_PROX; break;
case 'r': mods |= WasaQuery::WQM_REGEX; break;
case 's': mods |= WasaQuery::WQM_SLOPPY; break;
case 'w': mods |= WasaQuery::WQM_WORDS; break;
}
}
nclause->m_modifiers = WasaQuery::Modifier(mods);
}
// Field indicator ?
if (checkSubMatch(SMI_FIELD, match, reason)) {
// We used Check for special fields indicating sorting
// etc. here but this went away from the spec. See 1.4
// if it comes back
nclause->m_fieldspec = match;
if (checkSubMatch(SMI_REL, match, reason)) {
switch (match[0]) {
case '=':nclause->m_rel = WasaQuery::REL_EQUALS;break;
case ':':nclause->m_rel = WasaQuery::REL_CONTAINS;break;
case '<':
if (match[1] == '=')
nclause->m_rel = WasaQuery::REL_LTE;
else
nclause->m_rel = WasaQuery::REL_LT;
break;
case '>':
if (match[1] == '=')
nclause->m_rel = WasaQuery::REL_GTE;
else
nclause->m_rel = WasaQuery::REL_GT;
break;
default:
nclause->m_rel = WasaQuery::REL_CONTAINS;
}
} else {
// ?? If field matched we should have a relation
nclause->m_rel = WasaQuery::REL_CONTAINS;
}
}
// +- indicator ?
if (checkSubMatch(SMI_PM, match, reason) && match[0] == '-') {
nclause->m_op = WasaQuery::OP_EXCL;
} else {
nclause->m_op = WasaQuery::OP_LEAF;
}
if (prev_or) {
// The precedent token was an OR, add new clause to or chain
//DPRINT((stderr, "Adding to OR chain\n"));
orChain->m_subs.push_back(nclause);
} else {
if (orChain) {
// Getting out of OR. Add the OR subquery to the main one
//DPRINT((stderr, "Adding OR chain to main\n"));
query->m_subs.push_back(orChain);
orChain = 0;
}
//DPRINT((stderr, "Adding to main chain\n"));
// Add new clause to main query
query->m_subs.push_back(nclause);
}
prev_or = false;
}
nextfield:
// 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;
}
if (orChain) {
// Getting out of OR. Add the OR subquery to the main one
DPRINT((stderr, "Adding OR chain to main.Before: \n"));
DUMPQ(query);
DUMPQ(orChain);
query->m_subs.push_back(orChain);
}
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);
fprintf(stderr, "Finally: %s\n", desc.c_str());
exit(0);
}
#endif // TEST_WASASTRINGTOQUERY