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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/repl/idempotency_document_structure.h"
#include "mongo/db/exec/document_value/value.h"
#include "mongo/db/jsobj.h"
namespace mongo {
DocumentStructureEnumeratorConfig::DocumentStructureEnumeratorConfig(std::set<StringData> fields_,
std::size_t depth_,
std::size_t length_,
bool skipSubDocs_,
bool skipSubArrs_)
: fields(std::move(fields_)),
depth(depth_),
length(length_),
skipSubDocs(skipSubDocs_),
skipSubArrs(skipSubArrs_) {}
DocumentStructureEnumerator::iterator DocumentStructureEnumerator::begin() const {
return this->_docs.cbegin();
}
DocumentStructureEnumerator::iterator DocumentStructureEnumerator::end() const {
return this->_docs.cend();
}
std::vector<BSONObj> DocumentStructureEnumerator::getDocs() const {
return this->_docs;
}
BSONArrayBuilder DocumentStructureEnumerator::_getArrayBuilderFromArr(BSONArray arr) {
BSONArrayBuilder arrBuilder;
for (auto elem : arr) {
arrBuilder.append(elem);
}
return arrBuilder;
}
void DocumentStructureEnumerator::_enumerateFixedLenArrs(
const DocumentStructureEnumeratorConfig& config,
const ScalarGenerator* scalarGenerator,
BSONArray arr,
std::vector<BSONArray>* arrs) {
if (!config.length) {
// Base case: no more room for any other elements.
arrs->push_back(arr);
return;
}
// Otherwise, go through our choices, similar to the approach to documents.
//
DocumentStructureEnumeratorConfig nextElementConfig(config);
nextElementConfig.length--;
// Scalar.
BSONArrayBuilder scalarArr = _getArrayBuilderFromArr(arr);
scalarGenerator->generateScalar().addToBsonArray(&scalarArr);
_enumerateFixedLenArrs(nextElementConfig, scalarGenerator, scalarArr.arr(), arrs);
if (config.depth <= 0) {
return;
}
DocumentStructureEnumeratorConfig nextLayerConfig(config);
nextLayerConfig.depth--;
nextLayerConfig.length += arr.nFields();
// Subarray.
std::vector<BSONArray> subArrs = _enumerateArrs(nextLayerConfig, scalarGenerator);
for (const auto& subArr : subArrs) {
BSONArrayBuilder arrayArr = _getArrayBuilderFromArr(arr);
arrayArr.append(subArr);
_enumerateFixedLenArrs(nextElementConfig, scalarGenerator, arrayArr.arr(), arrs);
}
// Document.
if (!config.skipSubDocs) {
BSONObj blankDoc;
std::vector<BSONObj> subDocs;
_enumerateDocs(nextLayerConfig, scalarGenerator, blankDoc, &subDocs);
for (const auto& subDoc : subDocs) {
BSONArrayBuilder docArr = _getArrayBuilderFromArr(arr);
docArr.append(subDoc);
_enumerateFixedLenArrs(nextElementConfig, scalarGenerator, docArr.arr(), arrs);
}
}
return;
}
void DocumentStructureEnumerator::_enumerateDocs(const DocumentStructureEnumeratorConfig& config,
const ScalarGenerator* scalarGenerator,
BSONObj doc,
std::vector<BSONObj>* docs) {
if (config.fields.empty()) {
// Base case: when we have run out of fields to use.
docs->push_back(doc);
return;
}
// Create a copy of the fields we have.
std::set<StringData> remainingFields(config.fields);
// Pop the first field arbitrarily.
StringData field = *remainingFields.begin();
remainingFields.erase(remainingFields.begin());
DocumentStructureEnumeratorConfig nextFieldConfig(config);
nextFieldConfig.fields = remainingFields;
// Branch off depending on the choice.
//
// Scalar.
BSONObjBuilder scalarDoc(doc);
scalarGenerator->generateScalar().addToBsonObj(&scalarDoc, field);
_enumerateDocs(nextFieldConfig, scalarGenerator, scalarDoc.obj(), docs);
// Omit the field.
BSONObjBuilder vanishDoc(doc);
_enumerateDocs(nextFieldConfig, scalarGenerator, vanishDoc.obj(), docs);
if (config.depth <= 0) {
// If we are ever at the deepest level possible, we have no more choices after this.
return;
}
DocumentStructureEnumeratorConfig nextLayerConfig(nextFieldConfig);
nextLayerConfig.depth--;
if (!config.skipSubArrs) {
// Array.
for (const auto& subArr : _enumerateArrs(nextLayerConfig, scalarGenerator)) {
BSONObjBuilder arrayDoc(doc);
arrayDoc.append(field, subArr);
_enumerateDocs(nextFieldConfig, scalarGenerator, arrayDoc.obj(), docs);
}
}
// Subdocument.
if (!config.skipSubDocs) {
BSONObj blankDoc;
std::vector<BSONObj> subDocs;
_enumerateDocs(nextLayerConfig, scalarGenerator, blankDoc, &subDocs);
for (const auto& subDoc : subDocs) {
BSONObjBuilder docDoc(doc);
docDoc.append(field, subDoc);
_enumerateDocs(nextFieldConfig, scalarGenerator, docDoc.obj(), docs);
}
}
}
std::vector<BSONArray> DocumentStructureEnumerator::_enumerateArrs(
const DocumentStructureEnumeratorConfig& config, const ScalarGenerator* scalarGenerator) {
std::vector<BSONArray> arrs;
// We enumerate arrays of each possible length independently of each other to avoid having to
// account for how different omissions of elements in an array are equivalent to each other.
// For example, we'd otherwise need to treat omitting the first element and adding x as distinct
// from adding x and omitting the second element since both yield an array containing only the
// element x. Without this, we will enumerate duplicate arrays.
for (std::size_t i = 0; i <= config.length; i++) {
BSONArray emptyArr;
DocumentStructureEnumeratorConfig nextConfig(config);
nextConfig.length = i;
_enumerateFixedLenArrs(nextConfig, scalarGenerator, emptyArr, &arrs);
}
return arrs;
}
std::vector<BSONObj> DocumentStructureEnumerator::enumerateDocs() const {
BSONObj startDoc;
std::vector<BSONObj> docs;
_enumerateDocs(this->_config, this->_scalarGenerator, startDoc, &docs);
return docs;
}
std::vector<BSONArray> DocumentStructureEnumerator::enumerateArrs() const {
return _enumerateArrs(this->_config, this->_scalarGenerator);
}
DocumentStructureEnumerator::DocumentStructureEnumerator(DocumentStructureEnumeratorConfig config,
const ScalarGenerator* scalarGenerator)
: _config(std::move(config)), _scalarGenerator(scalarGenerator) {
this->_docs = enumerateDocs();
}
} // namespace mongo
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