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/**
* Copyright (C) 2021-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.
*/
#pragma once
#include "mongo/db/sorter/file.h"
#include "mongo/db/sorter/file_iterator.h"
#include "mongo/db/sorter/options.h"
#include "mongo/db/sorter/sorted_data_iterator.h"
#include "mongo/db/sorter/util.h"
#include "mongo/s/is_mongos.h"
namespace mongo::sorter {
template <typename Key, typename Value>
class SortedFileWriter {
public:
using Iterator = SortedDataIterator<Key, Value>;
using Settings = std::pair<typename Key::SorterDeserializeSettings,
typename Value::SorterDeserializeSettings>;
SortedFileWriter(File* file,
const boost::optional<std::string>& dbName = boost::none,
const Settings& settings = Settings())
: _settings(settings),
_file(file),
_fileStartOffset(_file->currentOffset()),
_dbName(dbName) {
invariant(!isMongos());
}
SortedFileWriter(const SortedFileWriter&) = delete;
SortedFileWriter& operator=(const SortedFileWriter&) = delete;
void addAlreadySorted(const Key& key, const Value& val) {
// Offset that points to the place in the buffer where a new data object will be stored.
int nextObjPos = _buffer.len();
// Add serialized key and value to the buffer.
key.serializeForSorter(_buffer);
val.serializeForSorter(_buffer);
// Serializing the key and value grows the buffer, but _buffer.buf() still points to the
// beginning. Use _buffer.len() to determine portion of buffer containing new datum.
_checksum =
addDataToChecksum(_buffer.buf() + nextObjPos, _buffer.len() - nextObjPos, _checksum);
if (_buffer.len() > 64 * 1024) {
_spill();
}
}
std::unique_ptr<Iterator> done() {
_spill();
return std::make_unique<FileIterator<Key, Value>>(
_file, _fileStartOffset, _file->currentOffset(), _checksum, _settings, _dbName);
}
private:
void _spill() {
int32_t size = _buffer.len();
char* outBuffer = _buffer.buf();
if (size == 0) {
return;
}
std::string compressed;
compress(outBuffer, size, &compressed);
invariant(compressed.size() <= size_t(std::numeric_limits<int32_t>::max()));
const bool shouldCompress = compressed.size() < size_t(_buffer.len() / 10 * 9);
if (shouldCompress) {
size = compressed.size();
outBuffer = const_cast<char*>(compressed.data());
}
std::unique_ptr<char[]> out;
if (auto encryptionHooks = getEncryptionHooksIfEnabled()) {
size_t protectedSizeMax = size + encryptionHooks->additionalBytesForProtectedBuffer();
out.reset(new char[protectedSizeMax]);
size_t resultLen;
Status status =
encryptionHooks->protectTmpData(reinterpret_cast<const uint8_t*>(outBuffer),
size,
reinterpret_cast<uint8_t*>(out.get()),
protectedSizeMax,
&resultLen,
_dbName);
uassert(28842,
str::stream() << "Failed to compress data: " << status.toString(),
status.isOK());
outBuffer = out.get();
size = resultLen;
}
// Negative size means compressed.
size = shouldCompress ? -size : size;
_file->write(reinterpret_cast<const char*>(&size), sizeof(size));
_file->write(outBuffer, std::abs(size));
_buffer.reset();
}
const Settings _settings;
File* _file;
BufBuilder _buffer;
// Keeps track of the hash of all data objects spilled to disk. Passed to the FileIterator
// to ensure data has not been corrupted after reading from disk.
uint32_t _checksum = 0;
// Tracks where in the file we started writing the sorted data range so that the information can
// be given to the Iterator in done().
std::streamoff _fileStartOffset;
boost::optional<std::string> _dbName;
};
} // namespace mongo::sorter
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