summaryrefslogtreecommitdiff
path: root/src/mongo/db/fts/fts_spec.cpp
blob: 1ec72152351d9821a106fb4385d60383e896004b (plain)
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
// fts_spec.cpp
/**
*    Copyright (C) 2012 10gen Inc.
*
*    This program is free software: you can redistribute it and/or  modify
*    it under the terms of the GNU Affero General Public License, version 3,
*    as published by the Free Software Foundation.
*
*    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 Affero General Public License for more details.
*
*    You should have received a copy of the GNU Affero General Public License
*    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*
*    As a special exception, the copyright holders give permission to link the
*    code of portions of this program with the OpenSSL library under certain
*    conditions as described in each individual source file and distribute
*    linked combinations including the program with the OpenSSL library. You
*    must comply with the GNU Affero General Public License in all respects for
*    all of the code used other than as permitted herein. If you modify file(s)
*    with this exception, you may extend this exception to your version of the
*    file(s), but you are not obligated to do so. If you do not wish to do so,
*    delete this exception statement from your version. If you delete this
*    exception statement from all source files in the program, then also delete
*    it in the license file.
*/

#include "mongo/platform/basic.h"

#include "mongo/db/fts/fts_spec.h"

#include "mongo/db/field_ref.h"
#include "mongo/db/fts/fts_element_iterator.h"
#include "mongo/db/fts/fts_tokenizer.h"
#include "mongo/db/fts/fts_util.h"
#include "mongo/util/mongoutils/str.h"
#include "mongo/util/stringutils.h"

namespace mongo {

namespace fts {

using std::map;
using std::string;
using namespace mongoutils;

const double DEFAULT_WEIGHT = 1;
const double MAX_WEIGHT = 1000000000;
const double MAX_WORD_WEIGHT = MAX_WEIGHT / 10000;

namespace {
// Default language.  Used for new indexes.
const std::string moduleDefaultLanguage("english");

/** Validate the given language override string. */
bool validateOverride(const string& override) {
    // The override field can't be empty, can't be prefixed with a dollar sign, and
    // can't contain a dot.
    return !override.empty() && override[0] != '$' && override.find('.') == std::string::npos;
}
}

FTSSpec::FTSSpec(const BSONObj& indexInfo) {
    // indexInfo is a text index spec.  Text index specs pass through fixSpec() before
    // being saved to the system.indexes collection.  fixSpec() enforces a schema, such that
    // required fields must exist and be of the correct type (e.g. weights,
    // textIndexVersion).
    massert(16739, "found invalid spec for text index", indexInfo["weights"].isABSONObj());
    BSONElement textIndexVersionElt = indexInfo["textIndexVersion"];
    massert(17367,
            "found invalid spec for text index, expected number for textIndexVersion",
            textIndexVersionElt.isNumber());

    // We currently support TEXT_INDEX_VERSION_1 (deprecated) and TEXT_INDEX_VERSION_2.
    // Reject all other values.
    massert(17364,
            str::stream() << "attempt to use unsupported textIndexVersion "
                          << textIndexVersionElt.numberInt() << "; versions supported: "
                          << TEXT_INDEX_VERSION_2 << ", " << TEXT_INDEX_VERSION_1,
            textIndexVersionElt.numberInt() == TEXT_INDEX_VERSION_2 ||
                textIndexVersionElt.numberInt() == TEXT_INDEX_VERSION_1);

    _textIndexVersion = (textIndexVersionElt.numberInt() == TEXT_INDEX_VERSION_2)
        ? TEXT_INDEX_VERSION_2
        : TEXT_INDEX_VERSION_1;

    // Initialize _defaultLanguage.  Note that the FTSLanguage constructor requires
    // textIndexVersion, since language parsing is version-specific.
    auto indexLanguage = indexInfo["default_language"].String();
    auto swl = FTSLanguage::make(indexLanguage, _textIndexVersion);

    // This can fail if the user originally created the text index under an instance of
    // MongoDB that supports different languages then the current instance
    // TODO: consder propagating the index ns to here to improve the error message
    uassert(28682,
            str::stream() << "Unrecognized language " << indexLanguage
                          << " found for text index. Verify mongod was started with the"
                             " correct options.",
            swl.getStatus().isOK());
    _defaultLanguage = swl.getValue();

    _languageOverrideField = indexInfo["language_override"].valuestrsafe();

    _wildcard = false;

    // in this block we fill in the _weights map
    {
        BSONObjIterator i(indexInfo["weights"].Obj());
        while (i.more()) {
            BSONElement e = i.next();
            verify(e.isNumber());

            if (WILDCARD == e.fieldName()) {
                _wildcard = true;
            } else {
                double num = e.number();
                _weights[e.fieldName()] = num;
                verify(num > 0 && num < MAX_WORD_WEIGHT);
            }
        }
        verify(_wildcard || _weights.size());
    }

    // extra information
    {
        BSONObj keyPattern = indexInfo["key"].Obj();
        verify(keyPattern.nFields() >= 2);
        BSONObjIterator i(keyPattern);

        bool passedFTS = false;

        while (i.more()) {
            BSONElement e = i.next();
            if (str::equals(e.fieldName(), "_fts") || str::equals(e.fieldName(), "_ftsx")) {
                passedFTS = true;
                continue;
            }

            if (passedFTS)
                _extraAfter.push_back(e.fieldName());
            else
                _extraBefore.push_back(e.fieldName());
        }
    }
}

const FTSLanguage* FTSSpec::_getLanguageToUseV2(const BSONObj& userDoc,
                                                const FTSLanguage* currentLanguage) const {
    BSONElement e = userDoc[_languageOverrideField];
    if (e.eoo()) {
        return currentLanguage;
    }
    uassert(17261,
            "found language override field in document with non-string type",
            e.type() == mongo::String);
    StatusWithFTSLanguage swl = FTSLanguage::make(e.String(), TEXT_INDEX_VERSION_2);
    uassert(17262, "language override unsupported: " + e.String(), swl.getStatus().isOK());
    return swl.getValue();
}

void FTSSpec::scoreDocument(const BSONObj& obj, TermFrequencyMap* term_freqs) const {
    if (_textIndexVersion == TEXT_INDEX_VERSION_1) {
        return _scoreDocumentV1(obj, term_freqs);
    }

    FTSElementIterator it(*this, obj);

    while (it.more()) {
        FTSIteratorValue val = it.next();
        std::unique_ptr<FTSTokenizer> tokenizer(val._language->createTokenizer());
        _scoreStringV2(tokenizer.get(), val._text, term_freqs, val._weight);
    }
}

void FTSSpec::_scoreStringV2(FTSTokenizer* tokenizer,
                             StringData raw,
                             TermFrequencyMap* docScores,
                             double weight) const {
    ScoreHelperMap terms;

    unsigned numTokens = 0;

    tokenizer->reset(raw.rawData(), FTSTokenizer::kFilterStopWords);

    while (tokenizer->moveNext()) {
        string term = tokenizer->get().toString();

        ScoreHelperStruct& data = terms[term];

        if (data.exp) {
            data.exp *= 2;
        } else {
            data.exp = 1;
        }
        data.count += 1;
        data.freq += (1 / data.exp);
        numTokens++;
    }

    for (ScoreHelperMap::const_iterator i = terms.begin(); i != terms.end(); ++i) {
        const string& term = i->first;
        const ScoreHelperStruct& data = i->second;

        // in order to adjust weights as a function of term count as it
        // relates to total field length. ie. is this the only word or
        // a frequently occuring term? or does it only show up once in
        // a long block of text?

        double coeff = (0.5 * data.count / numTokens) + 0.5;

        // if term is identical to the raw form of the
        // field (untokenized) give it a small boost.
        double adjustment = 1;
        if (raw.size() == term.length() && raw.equalCaseInsensitive(term))
            adjustment += 0.1;

        double& score = (*docScores)[term];
        score += (weight * data.freq * coeff * adjustment);
        verify(score <= MAX_WEIGHT);
    }
}

Status FTSSpec::getIndexPrefix(const BSONObj& query, BSONObj* out) const {
    if (numExtraBefore() == 0) {
        *out = BSONObj();
        return Status::OK();
    }

    BSONObjBuilder b;
    for (unsigned i = 0; i < numExtraBefore(); i++) {
        BSONElement e = query.getFieldDotted(extraBefore(i));
        if (e.eoo())
            return Status(ErrorCodes::BadValue,
                          str::stream() << "need have an equality filter on: " << extraBefore(i));

        if (e.isABSONObj() && e.Obj().firstElement().getGtLtOp(-1) != -1)
            return Status(ErrorCodes::BadValue,
                          str::stream() << "need have an equality filter on: " << extraBefore(i));

        b.append(e);
    }
    *out = b.obj();
    return Status::OK();
}

namespace {
void _addFTSStuff(BSONObjBuilder* b) {
    b->append("_fts", INDEX_NAME);
    b->append("_ftsx", 1);
}

void verifyFieldNameNotReserved(StringData s) {
    uassert(17289,
            "text index with reserved fields _fts/_ftsx not allowed",
            s != "_fts" && s != "_ftsx");
}
}

BSONObj FTSSpec::fixSpec(const BSONObj& spec) {
    if (spec["textIndexVersion"].numberInt() == TEXT_INDEX_VERSION_1) {
        return _fixSpecV1(spec);
    }

    map<string, int> m;

    BSONObj keyPattern;
    {
        BSONObjBuilder b;

        // Populate m and keyPattern.
        {
            bool addedFtsStuff = false;
            BSONObjIterator i(spec["key"].Obj());
            while (i.more()) {
                BSONElement e = i.next();
                if (str::equals(e.fieldName(), "_fts")) {
                    uassert(17271, "expecting _fts:\"text\"", INDEX_NAME == e.valuestrsafe());
                    addedFtsStuff = true;
                    b.append(e);
                } else if (str::equals(e.fieldName(), "_ftsx")) {
                    uassert(17272, "expecting _ftsx:1", e.numberInt() == 1);
                    b.append(e);
                } else if (e.type() == String && INDEX_NAME == e.valuestr()) {
                    if (!addedFtsStuff) {
                        _addFTSStuff(&b);
                        addedFtsStuff = true;
                    }

                    m[e.fieldName()] = 1;
                } else {
                    uassert(17273,
                            "expected value 1 or -1 for non-text key in compound index",
                            e.numberInt() == 1 || e.numberInt() == -1);
                    b.append(e);
                }
            }
            verify(addedFtsStuff);
        }
        keyPattern = b.obj();

        // Verify that index key is in the correct format: extraBefore fields, then text
        // fields, then extraAfter fields.
        {
            BSONObjIterator i(spec["key"].Obj());
            verify(i.more());
            BSONElement e = i.next();

            // extraBefore fields
            while (String != e.type()) {
                verifyFieldNameNotReserved(e.fieldNameStringData());
                verify(i.more());
                e = i.next();
            }

            // text fields
            bool alreadyFixed = str::equals(e.fieldName(), "_fts");
            if (alreadyFixed) {
                uassert(17288, "expected _ftsx after _fts", i.more());
                e = i.next();
                uassert(17274, "expected _ftsx after _fts", str::equals(e.fieldName(), "_ftsx"));
                e = i.next();
            } else {
                do {
                    verifyFieldNameNotReserved(e.fieldNameStringData());
                    e = i.next();
                } while (!e.eoo() && e.type() == String);
            }

            // extraAfterFields
            while (!e.eoo()) {
                uassert(17389, "'text' fields in index must all be adjacent", e.type() != String);
                verifyFieldNameNotReserved(e.fieldNameStringData());
                e = i.next();
            }
        }
    }

    if (spec["weights"].type() == Object) {
        BSONObjIterator i(spec["weights"].Obj());
        while (i.more()) {
            BSONElement e = i.next();
            uassert(17283, "weight for text index needs numeric type", e.isNumber());
            m[e.fieldName()] = e.numberInt();
        }
    } else if (spec["weights"].str() == WILDCARD) {
        m[WILDCARD] = 1;
    } else if (!spec["weights"].eoo()) {
        uasserted(17284, "text index option 'weights' must be an object");
    }

    BSONObj weights;
    {
        BSONObjBuilder b;
        for (map<string, int>::iterator i = m.begin(); i != m.end(); ++i) {
            uassert(16674, "score for word too high", i->second > 0 && i->second < MAX_WORD_WEIGHT);

            // Verify weight refers to a valid field.
            if (i->first != "$**") {
                FieldRef keyField(i->first);
                uassert(17294, "weight cannot be on an empty field", keyField.numParts() != 0);
                for (size_t partNum = 0; partNum < keyField.numParts(); partNum++) {
                    StringData part = keyField.getPart(partNum);
                    uassert(17291, "weight cannot have empty path component", !part.empty());
                    uassert(17292,
                            "weight cannot have path component with $ prefix",
                            !part.startsWith("$"));
                }
            }

            b.append(i->first, i->second);
        }
        weights = b.obj();
    }

    BSONElement default_language_elt = spec["default_language"];
    string default_language(default_language_elt.str());
    if (default_language_elt.eoo()) {
        default_language = moduleDefaultLanguage;
    } else {
        uassert(
            17263, "default_language needs a string type", default_language_elt.type() == String);
    }
    uassert(17264,
            "default_language is not valid",
            FTSLanguage::make(default_language, TEXT_INDEX_VERSION_2).getStatus().isOK());

    BSONElement language_override_elt = spec["language_override"];
    string language_override(language_override_elt.str());
    if (language_override_elt.eoo()) {
        language_override = "language";
    } else {
        uassert(17136,
                "language_override is not valid",
                language_override_elt.type() == String && validateOverride(language_override));
    }

    int version = -1;
    int textIndexVersion = TEXT_INDEX_VERSION_2;

    BSONObjBuilder b;
    BSONObjIterator i(spec);
    while (i.more()) {
        BSONElement e = i.next();
        if (str::equals(e.fieldName(), "key")) {
            b.append("key", keyPattern);
        } else if (str::equals(e.fieldName(), "weights")) {
            b.append("weights", weights);
            weights = BSONObj();
        } else if (str::equals(e.fieldName(), "default_language")) {
            b.append("default_language", default_language);
            default_language = "";
        } else if (str::equals(e.fieldName(), "language_override")) {
            b.append("language_override", language_override);
            language_override = "";
        } else if (str::equals(e.fieldName(), "v")) {
            version = e.numberInt();
        } else if (str::equals(e.fieldName(), "textIndexVersion")) {
            uassert(17293, "text index option 'textIndexVersion' must be a number", e.isNumber());
            textIndexVersion = e.numberInt();
            uassert(16730,
                    str::stream() << "bad textIndexVersion: " << textIndexVersion,
                    textIndexVersion == TEXT_INDEX_VERSION_2);
        } else {
            b.append(e);
        }
    }

    if (!weights.isEmpty()) {
        b.append("weights", weights);
    }
    if (!default_language.empty()) {
        b.append("default_language", default_language);
    }
    if (!language_override.empty()) {
        b.append("language_override", language_override);
    }
    if (version >= 0) {
        b.append("v", version);
    }
    b.append("textIndexVersion", textIndexVersion);

    return b.obj();
}
}
}