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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/ftdc/decompressor.h"
#include "mongo/base/data_range_cursor.h"
#include "mongo/base/data_type_validated.h"
#include "mongo/db/ftdc/compressor.h"
#include "mongo/db/ftdc/util.h"
#include "mongo/db/ftdc/varint.h"
#include "mongo/db/jsobj.h"
#include "mongo/rpc/object_check.h"
#include "mongo/util/assert_util.h"
namespace mongo {
StatusWith<std::vector<BSONObj>> FTDCDecompressor::uncompress(ConstDataRange buf) {
ConstDataRangeCursor compressedDataRange(buf);
// Read the length of the uncompressed buffer
auto swUncompressedLength = compressedDataRange.readAndAdvance<LittleEndian<std::uint32_t>>();
if (!swUncompressedLength.isOK()) {
return {swUncompressedLength.getStatus()};
}
// Now uncompress the data
// Limit size of the buffer we need zlib
auto uncompressedLength = swUncompressedLength.getValue();
if (uncompressedLength > 10000000) {
return Status(ErrorCodes::InvalidLength, "Metrics chunk has exceeded the allowable size.");
}
auto statusUncompress = _compressor.uncompress(compressedDataRange, uncompressedLength);
if (!statusUncompress.isOK()) {
return {statusUncompress.getStatus()};
}
ConstDataRangeCursor cdc = statusUncompress.getValue();
// The document is not part of any checksum so we must validate it is correct
auto swRef = cdc.readAndAdvance<Validated<BSONObj>>();
if (!swRef.isOK()) {
return {swRef.getStatus()};
}
BSONObj ref = swRef.getValue();
// Read count of metrics
auto swMetricsCount = cdc.readAndAdvance<LittleEndian<std::uint32_t>>();
if (!swMetricsCount.isOK()) {
return {swMetricsCount.getStatus()};
}
std::uint32_t metricsCount = swMetricsCount.getValue();
// Read count of samples
auto swSampleCount = cdc.readAndAdvance<LittleEndian<std::uint32_t>>();
if (!swSampleCount.isOK()) {
return {swSampleCount.getStatus()};
}
std::uint32_t sampleCount = swSampleCount.getValue();
// Limit size of the buffer we need for metrics and samples
if (metricsCount * sampleCount > 1000000) {
return Status(ErrorCodes::InvalidLength,
"Metrics Count and Sample Count have exceeded the allowable range.");
}
std::vector<std::uint64_t> metrics;
metrics.reserve(metricsCount);
// We pass the reference document as both the reference document and current document as we only
// want the array of metrics.
(void)FTDCBSONUtil::extractMetricsFromDocument(ref, ref, &metrics);
if (metrics.size() != metricsCount) {
return {ErrorCodes::BadValue,
"The metrics in the reference document and metrics count do not match"};
}
std::vector<BSONObj> docs;
// Allocate space for the reference document + samples
docs.reserve(1 + sampleCount);
docs.emplace_back(ref.getOwned());
// We must always return the reference document
if (sampleCount == 0) {
return {docs};
}
// Read the samples
std::vector<std::uint64_t> deltas(metricsCount * sampleCount);
// decompress the deltas
std::uint64_t zeroesCount = 0;
auto cdrc = ConstDataRangeCursor(cdc);
for (std::uint32_t i = 0; i < metricsCount; i++) {
for (std::uint32_t j = 0; j < sampleCount; j++) {
if (zeroesCount) {
deltas[FTDCCompressor::getArrayOffset(sampleCount, j, i)] = 0;
zeroesCount--;
continue;
}
auto swDelta = cdrc.readAndAdvance<FTDCVarInt>();
if (!swDelta.isOK()) {
return swDelta.getStatus();
}
if (swDelta.getValue() == 0) {
auto swZero = cdrc.readAndAdvance<FTDCVarInt>();
if (!swZero.isOK()) {
return swDelta.getStatus();
}
zeroesCount = swZero.getValue();
}
deltas[FTDCCompressor::getArrayOffset(sampleCount, j, i)] = swDelta.getValue();
}
}
// Inflate the deltas
for (std::uint32_t i = 0; i < metricsCount; i++) {
deltas[FTDCCompressor::getArrayOffset(sampleCount, 0, i)] += metrics[i];
}
for (std::uint32_t i = 0; i < metricsCount; i++) {
for (std::uint32_t j = 1; j < sampleCount; j++) {
deltas[FTDCCompressor::getArrayOffset(sampleCount, j, i)] +=
deltas[FTDCCompressor::getArrayOffset(sampleCount, j - 1, i)];
}
}
for (std::uint32_t i = 0; i < sampleCount; ++i) {
for (std::uint32_t j = 0; j < metricsCount; ++j) {
metrics[j] = deltas[j * sampleCount + i];
}
docs.emplace_back(FTDCBSONUtil::constructDocumentFromMetrics(ref, metrics).getValue());
}
return {docs};
}
} // namespace mongo
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