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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/platform/basic.h"
#include "mongo/db/pipeline/field_path.h"
#include "mongo/db/query/query_feature_flags_gen.h"
#include "mongo/db/query/query_knobs_gen.h"
#include "mongo/base/string_data.h"
#include "mongo/bson/bson_depth.h"
#include "mongo/util/str.h"
#include "mongo/util/string_map.h"
namespace mongo {
namespace {
const StringDataSet kAllowedDollarPrefixedFields = {
// For DBRef
"$id"_sd,
"$ref"_sd,
"$db"_sd,
// Metadata fields.
// This is necessary for sharded query execution of find() commands. mongos may attach a
// $sortKey field to the projection sent to shards so that it can merge the results correctly.
"$sortKey",
// This is necessary for the "showRecordId" feature.
"$recordId"};
} // namespace
using std::string;
using std::vector;
string FieldPath::getFullyQualifiedPath(StringData prefix, StringData suffix) {
if (prefix.empty()) {
return suffix.toString();
}
return str::stream() << prefix << "." << suffix;
}
FieldPath::FieldPath(std::string inputPath)
: _fieldPath(std::move(inputPath)), _fieldPathDotPosition{string::npos} {
uassert(40352, "FieldPath cannot be constructed with empty string", !_fieldPath.empty());
uassert(40353, "FieldPath must not end with a '.'.", _fieldPath[_fieldPath.size() - 1] != '.');
// Store index delimiter position for use in field lookup.
size_t dotPos;
size_t startPos = 0;
while (string::npos != (dotPos = _fieldPath.find('.', startPos))) {
_fieldPathDotPosition.push_back(dotPos);
startPos = dotPos + 1;
}
_fieldPathDotPosition.push_back(_fieldPath.size());
// Validate the path length and the fields.
const auto pathLength = getPathLength();
uassert(ErrorCodes::Overflow,
"FieldPath is too long",
pathLength <= BSONDepth::getMaxAllowableDepth());
for (size_t i = 0; i < pathLength; ++i) {
uassertValidFieldName(getFieldName(i));
}
}
void FieldPath::uassertValidFieldName(StringData fieldName) {
uassert(15998, "FieldPath field names may not be empty strings.", !fieldName.empty());
const auto dotsAndDollarsHint =
feature_flags::gFeatureFlagDotsAndDollars.isEnabledAndIgnoreFCV()
? " Consider using $getField or $setField."
: "";
if (fieldName[0] == '$' && !kAllowedDollarPrefixedFields.count(fieldName)) {
uasserted(16410,
str::stream() << "FieldPath field names may not start with '$'."
<< dotsAndDollarsHint);
}
uassert(
16411, "FieldPath field names may not contain '\0'.", fieldName.find('\0') == string::npos);
uassert(16412,
str::stream() << "FieldPath field names may not contain '.'." << dotsAndDollarsHint,
fieldName.find('.') == string::npos);
}
FieldPath FieldPath::concat(const FieldPath& tail) const {
const FieldPath& head = *this;
std::string concat;
const auto expectedStringSize = _fieldPath.size() + 1 + tail._fieldPath.size();
concat.reserve(expectedStringSize);
concat.insert(concat.begin(), head._fieldPath.begin(), head._fieldPath.end());
concat.push_back('.');
concat.insert(concat.end(), tail._fieldPath.begin(), tail._fieldPath.end());
invariant(concat.size() == expectedStringSize);
std::vector<size_t> newDots;
// Subtract 2 since both contain std::string::npos at the beginning and the entire size at
// the end. Add one because we inserted a dot in order to concatenate the two paths.
const auto expectedDotSize =
head._fieldPathDotPosition.size() + tail._fieldPathDotPosition.size() - 2 + 1;
newDots.reserve(expectedDotSize);
// The first one in head._fieldPathDotPosition is npos. The last one, is, conveniently, the
// size of head fieldPath, which also happens to be the index at which we added a new dot.
newDots.insert(
newDots.begin(), head._fieldPathDotPosition.begin(), head._fieldPathDotPosition.end());
invariant(tail._fieldPathDotPosition.size() >= 2);
for (size_t i = 1; i < tail._fieldPathDotPosition.size(); ++i) {
// Move each index back by size of the first field path, plus one, for the newly added dot.
newDots.push_back(tail._fieldPathDotPosition[i] + head._fieldPath.size() + 1);
}
invariant(newDots.back() == concat.size());
invariant(newDots.size() == expectedDotSize);
return FieldPath(std::move(concat), std::move(newDots));
}
} // namespace mongo
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