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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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/db/keypattern.h"
#include "mongo/db/index_names.h"
namespace mongo {
KeyPattern::KeyPattern(const BSONObj& pattern) : _pattern(pattern) {}
bool KeyPattern::isIdKeyPattern(const BSONObj& pattern) {
BSONObjIterator i(pattern);
BSONElement e = i.next();
// _id index must have form exactly {_id : 1} or {_id : -1}.
// Allows an index of form {_id : "hashed"} to exist but
// do not consider it to be the primary _id index
return (0 == strcmp(e.fieldName(), "_id")) && (e.numberInt() == 1 || e.numberInt() == -1) &&
i.next().eoo();
}
bool KeyPattern::isOrderedKeyPattern(const BSONObj& pattern) {
return IndexNames::BTREE == IndexNames::findPluginName(pattern);
}
bool KeyPattern::isHashedKeyPattern(const BSONObj& pattern) {
return IndexNames::HASHED == IndexNames::findPluginName(pattern);
}
StringBuilder& operator<<(StringBuilder& sb, const KeyPattern& keyPattern) {
// Rather than return BSONObj::toString() we construct a keyPattern string manually. This allows
// us to avoid the cost of writing numeric direction to the str::stream which will then undergo
// expensive number to string conversion.
sb << "{ ";
bool first = true;
for (auto&& elem : keyPattern._pattern) {
if (first) {
first = false;
} else {
sb << ", ";
}
if (mongo::String == elem.type()) {
sb << elem;
} else if (elem.number() >= 0) {
// The canonical check as to whether a key pattern element is "ascending" or
// "descending" is (elem.number() >= 0). This is defined by the Ordering class.
sb << elem.fieldNameStringData() << ": 1";
} else {
sb << elem.fieldNameStringData() << ": -1";
}
}
sb << " }";
return sb;
}
BSONObj KeyPattern::extendRangeBound(const BSONObj& bound, bool makeUpperInclusive) const {
BSONObjBuilder newBound(bound.objsize());
BSONObjIterator src(bound);
BSONObjIterator pat(_pattern);
while (src.more()) {
massert(16649,
str::stream() << "keyPattern " << _pattern << " shorter than bound " << bound,
pat.more());
BSONElement srcElt = src.next();
BSONElement patElt = pat.next();
massert(16634,
str::stream() << "field names of bound " << bound
<< " do not match those of keyPattern "
<< _pattern,
str::equals(srcElt.fieldName(), patElt.fieldName()));
newBound.append(srcElt);
}
while (pat.more()) {
BSONElement patElt = pat.next();
// for non 1/-1 field values, like {a : "hashed"}, treat order as ascending
int order = patElt.isNumber() ? patElt.numberInt() : 1;
// flip the order semantics if this is an upper bound
if (makeUpperInclusive)
order *= -1;
if (order > 0) {
newBound.appendMinKey(patElt.fieldName());
} else {
newBound.appendMaxKey(patElt.fieldName());
}
}
return newBound.obj();
}
BSONObj KeyPattern::globalMin() const {
return extendRangeBound(BSONObj(), false);
}
BSONObj KeyPattern::globalMax() const {
return extendRangeBound(BSONObj(), true);
}
} // namespace mongo
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