/usr/include/xapian-1.3/xapian/query.h is in libxapian-1.3-dev 1.3.4-0ubuntu6.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 | /** @file query.h
* @brief Xapian::Query API class
*/
/* Copyright (C) 2011,2012,2013,2014,2015 Olly Betts
* Copyright (C) 2008 Richard Boulton
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef XAPIAN_INCLUDED_QUERY_H
#define XAPIAN_INCLUDED_QUERY_H
#if !defined XAPIAN_IN_XAPIAN_H && !defined XAPIAN_LIB_BUILD
# error "Never use <xapian/query.h> directly; include <xapian.h> instead."
#endif
#include <string>
#include <xapian/attributes.h>
#include <xapian/intrusive_ptr.h>
#include <xapian/postingiterator.h>
#include <xapian/registry.h>
#include <xapian/termiterator.h>
#include <xapian/types.h>
#include <xapian/visibility.h>
class QueryOptimiser; // FIXME
namespace Xapian {
class PostingSource;
/// Class representing a query.
class XAPIAN_VISIBILITY_DEFAULT Query {
public:
/// Class representing the query internals.
class Internal;
/// @private @internal Reference counted internals.
Xapian::Internal::intrusive_ptr<Internal> internal;
static const Xapian::Query MatchNothing;
static const Xapian::Query MatchAll;
/** Query operators. */
enum op {
OP_AND = 0,
OP_OR = 1,
OP_AND_NOT = 2,
OP_XOR = 3,
OP_AND_MAYBE = 4,
OP_FILTER = 5,
OP_NEAR = 6,
OP_PHRASE = 7,
OP_VALUE_RANGE = 8,
OP_SCALE_WEIGHT = 9,
/** Pick the best N subqueries and combine with OP_OR.
*
* If you want to implement a feature which finds documents similar to
* a piece of text, an obvious approach is to build an "OR" query from
* all the terms in the text, and run this query against a database
* containing the documents. However such a query can contain a lots
* of terms and be quite slow to perform, yet many of these terms
* don't contribute usefully to the results.
*
* The OP_ELITE_SET operator can be used instead of OP_OR in this
* situation. OP_ELITE_SET selects the most important ''N'' terms and
* then acts as an OP_OR query with just these, ignoring any other
* terms. This will usually return results just as good as the full
* OP_OR query, but much faster.
*
* In general, the OP_ELITE_SET operator can be used when you have a
* large OR query, but it doesn't matter if the search completely
* ignores some of the less important terms in the query.
*
* The subqueries don't have to be terms, but if they aren't then
* OP_ELITE_SET will look at the estimated frequencies of the
* subqueries and so could pick a subset which don't actually
* match any documents even if the full OR would match some.
*
* You can specify a parameter to the query constructor which control
* the number of terms which OP_ELITE_SET will pick. If not
* specified, this defaults to 10 (Xapian used to default to
* <code>ceil(sqrt(number_of_subqueries))</code> if there are more
* than 100 subqueries, but this rather arbitrary special case was
* dropped in 1.3.0). For example, this will pick the best 7 terms:
*
* <pre>
* Xapian::Query query(Xapian::Query::OP_ELITE_SET, subqs.begin(), subqs.end(), 7);
* </pre>
*
* If the number of subqueries is less than this threshold,
* OP_ELITE_SET behaves identically to OP_OR.
*/
OP_ELITE_SET = 10,
OP_VALUE_GE = 11,
OP_VALUE_LE = 12,
OP_SYNONYM = 13,
OP_MAX = 14,
OP_WILDCARD = 15,
LEAF_TERM = 100,
LEAF_POSTING_SOURCE,
LEAF_MATCH_ALL,
LEAF_MATCH_NOTHING
};
enum {
/** Throw an error if OP_WILDCARD exceeds its expansion limit.
*
* Xapian::WildcardError will be thrown when the query is actually
* run.
*/
WILDCARD_LIMIT_ERROR,
/** Stop expanding when OP_WILDCARD reaches its expansion limit.
*
* This makes the wildcard expand to only the first N terms (sorted
* by byte order).
*/
WILDCARD_LIMIT_FIRST,
/** Limit OP_WILDCARD expansion to the most frequent terms.
*
* If OP_WILDCARD would expand to more than its expansion limit, the
* most frequent terms are taken. This approach works well for cases
* such as expanding a partial term at the end of a query string which
* the user hasn't finished typing yet - as well as being less expense
* to evaluate than the full expansion, using only the most frequent
* terms tends to give better results too.
*/
WILDCARD_LIMIT_MOST_FREQUENT
};
/// Default constructor.
XAPIAN_NOTHROW(Query())
: internal(0) { }
/// Destructor.
~Query() { }
/** Copying is allowed.
*
* The internals are reference counted, so copying is cheap.
*/
Query(const Query & o) : internal(o.internal) { }
/** Copying is allowed.
*
* The internals are reference counted, so assignment is cheap.
*/
Query & operator=(const Query & o) { internal = o.internal; return *this; }
/** Construct a Query object for a term. */
Query(const std::string & term,
Xapian::termcount wqf = 1,
Xapian::termpos pos = 0);
/** Construct a Query object for a PostingSource. */
explicit Query(Xapian::PostingSource * source);
// FIXME: new form for OP_SCALE_WEIGHT - do we want this?
Query(double factor, const Xapian::Query & subquery);
// FIXME: legacy form of above (assuming we want to add that...)
Query(op op_, const Xapian::Query & subquery, double factor);
// Pairwise.
Query(op op_, const Xapian::Query & a, const Xapian::Query & b)
{
init(op_, 2);
add_subquery(a);
add_subquery(b);
done();
}
// Pairwise with std::string.
Query(op op_, const std::string & a, const std::string & b)
{
init(op_, 2);
add_subquery(a);
add_subquery(b);
done();
}
// OP_VALUE_GE/OP_VALUE_LE
Query(op op_, Xapian::valueno slot, const std::string & limit);
// OP_VALUE_RANGE
Query(op op_, Xapian::valueno slot,
const std::string & begin, const std::string & end);
/** Query constructor for OP_WILDCARD queries.
*
* @param op Must be OP_WILDCARD
* @param pattern The wildcard pattern - currently this is just a string
* and the wildcard expands to terms which start with
* exactly this string.
* @param max_expansion The maximum number of terms to expand to
* (default: 0, which means no limit)
* @param max_type How to enforce max_expansion - one of
* @a WILDCARD_LIMIT_ERROR (the default),
* @a WILDCARD_LIMIT_FIRST or
* @a WILDCARD_LIMIT_MOST_FREQUENT.
* @param combiner The @op to combine the terms with - one of
* @a OP_SYNONYM (the default), @a OP_OR or @a OP_MAX.
*/
Query(op op_,
const std::string & pattern,
Xapian::termcount max_expansion = 0,
int max_type = WILDCARD_LIMIT_ERROR,
op combiner = OP_SYNONYM);
template<typename I>
Query(op op_, I begin, I end, Xapian::termcount window = 0)
{
if (begin != end) {
typedef typename std::iterator_traits<I>::iterator_category iterator_category;
init(op_, window, begin, end, iterator_category());
for (I i = begin; i != end; ++i) {
add_subquery(*i);
}
}
done();
}
#ifdef SWIG
// SWIG's %template doesn't seem to handle a templated ctor so we
// provide this fake specialised form of the above prototype.
Query(op op_, XapianSWIGQueryItor qbegin, XapianSWIGQueryItor qend,
Xapian::termcount parameter = 0);
# ifdef SWIGJAVA
Query(op op_, XapianSWIGStrItor qbegin, XapianSWIGStrItor qend,
Xapian::termcount parameter = 0);
# endif
#endif
const TermIterator get_terms_begin() const;
const TermIterator XAPIAN_NOTHROW(get_terms_end() const) {
return TermIterator();
}
const TermIterator get_unique_terms_begin() const;
Xapian::termcount XAPIAN_NOTHROW(get_length() const) XAPIAN_PURE_FUNCTION;
bool XAPIAN_NOTHROW(empty() const) {
return internal.get() == 0;
}
std::string serialise() const;
static const Query unserialise(const std::string & serialised,
const Registry & reg = Registry());
/** Get the type of the top level of the query. */
op XAPIAN_NOTHROW(get_type() const) XAPIAN_PURE_FUNCTION;
/** Get the number of subqueries of the top level query. */
size_t XAPIAN_NOTHROW(get_num_subqueries() const) XAPIAN_PURE_FUNCTION;
/** Read a top level subquery.
*
* @param n Return the n-th subquery (starting from 0) - only valid when
* 0 <= n < get_num_subqueries().
*/
const Query get_subquery(size_t n) const;
std::string get_description() const;
const Query operator&=(const Query & o) {
return (*this = Query(OP_AND, *this, o));
}
const Query operator|=(const Query & o) {
return (*this = Query(OP_OR, *this, o));
}
const Query operator^=(const Query & o) {
return (*this = Query(OP_XOR, *this, o));
}
const Query operator*=(double factor) {
return (*this = Query(factor, *this));
}
const Query operator/=(double factor) {
return (*this = Query(1.0 / factor, *this));
}
/** @private @internal */
explicit Query(Internal * internal_) : internal(internal_) { }
private:
void init(Query::op op_, size_t n_subqueries, Xapian::termcount window = 0);
template<typename I>
void init(Query::op op_, Xapian::termcount window,
const I & begin, const I & end, std::random_access_iterator_tag)
{
init(op_, end - begin, window);
}
template<typename I>
void init(Query::op op_, Xapian::termcount window,
const I &, const I &, std::input_iterator_tag)
{
init(op_, 0, window);
}
void add_subquery(const Xapian::Query & subquery);
void add_subquery(const std::string & subquery) {
add_subquery(Xapian::Query(subquery));
}
void add_subquery(const Xapian::Query * subquery) {
// FIXME: subquery NULL?
add_subquery(*subquery);
}
void done();
};
inline const Query
operator&(const Query & a, const Query & b)
{
return Query(Query::OP_AND, a, b);
}
inline const Query
operator|(const Query & a, const Query & b)
{
return Query(Query::OP_OR, a, b);
}
inline const Query
operator^(const Query & a, const Query & b)
{
return Query(Query::OP_XOR, a, b);
}
inline const Query
operator*(double factor, const Query & q)
{
return Query(factor, q);
}
inline const Query
operator*(const Query & q, double factor)
{
return Query(factor, q);
}
inline const Query
operator/(const Query & q, double factor)
{
return Query(1.0 / factor, q);
}
class InvertedQuery_ {
const Query & query;
void operator=(const InvertedQuery_ &);
explicit InvertedQuery_(const Query & query_) : query(query_) { }
public:
// GCC 4.2 seems to needs a copy ctor.
InvertedQuery_(const InvertedQuery_ & o) : query(o.query) { }
operator Query() const {
return Query(Query::OP_AND_NOT, Query::MatchAll, query);
}
friend const InvertedQuery_ operator~(const Query &q);
friend const Query operator&(const Query & a, const InvertedQuery_ & b);
};
inline const Query
operator&(const Query & a, const InvertedQuery_ & b)
{
return Query(Query::OP_AND_NOT, a, b.query);
}
inline const InvertedQuery_
operator~(const Query &q)
{
return InvertedQuery_(q);
}
namespace Internal {
class AndContext;
class OrContext;
class XorContext;
}
class Query::Internal : public Xapian::Internal::intrusive_base {
public:
XAPIAN_NOTHROW(Internal()) { }
virtual ~Internal();
virtual PostingIterator::Internal * postlist(QueryOptimiser * qopt, double factor) const = 0;
virtual void postlist_sub_and_like(Xapian::Internal::AndContext& ctx,
QueryOptimiser * qopt,
double factor) const;
virtual void postlist_sub_or_like(Xapian::Internal::OrContext& ctx,
QueryOptimiser * qopt,
double factor) const;
virtual void postlist_sub_xor(Xapian::Internal::XorContext& ctx,
QueryOptimiser * qopt,
double factor) const;
virtual termcount XAPIAN_NOTHROW(get_length() const) XAPIAN_PURE_FUNCTION;
virtual void serialise(std::string & result) const = 0;
static Query::Internal * unserialise(const char ** p, const char * end, const Registry & reg);
virtual Query::op XAPIAN_NOTHROW(get_type() const) XAPIAN_PURE_FUNCTION = 0;
virtual size_t XAPIAN_NOTHROW(get_num_subqueries() const) XAPIAN_PURE_FUNCTION;
virtual const Query get_subquery(size_t n) const;
virtual std::string get_description() const = 0;
// Pass argument as void* to avoid need to include <vector>.
virtual void gather_terms(void * void_terms) const;
};
}
#endif // XAPIAN_INCLUDED_QUERY_H
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