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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/resume_token.h"
#include <boost/optional/optional_io.hpp>
#include <limits>
#include "mongo/bson/bsonmisc.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/db/pipeline/document_source_change_stream_gen.h"
#include "mongo/db/pipeline/value_comparator.h"
#include "mongo/db/storage/key_string.h"
#include "mongo/util/hex.h"
namespace mongo {
constexpr StringData ResumeToken::kDataFieldName;
constexpr StringData ResumeToken::kTypeBitsFieldName;
namespace {
// Helper function for makeHighWaterMarkToken and isHighWaterMarkToken.
ResumeTokenData makeHighWaterMarkResumeTokenData(Timestamp clusterTime,
boost::optional<UUID> uuid) {
ResumeTokenData tokenData;
tokenData.clusterTime = clusterTime;
tokenData.tokenType = ResumeTokenData::kHighWaterMarkToken;
tokenData.uuid = uuid;
return tokenData;
}
} // namespace
bool ResumeTokenData::operator==(const ResumeTokenData& other) const {
return clusterTime == other.clusterTime && version == other.version &&
tokenType == other.tokenType && applyOpsIndex == other.applyOpsIndex &&
fromInvalidate == other.fromInvalidate && uuid == other.uuid &&
(Value::compare(this->documentKey, other.documentKey, nullptr) == 0);
}
std::ostream& operator<<(std::ostream& out, const ResumeTokenData& tokenData) {
out << "{clusterTime: " << tokenData.clusterTime.toString();
out << ", version: " << tokenData.version;
if (tokenData.version > 0) {
out << ", tokenType: " << tokenData.tokenType;
}
out << ", applyOpsIndex: " << tokenData.applyOpsIndex;
if (tokenData.version > 0) {
out << ", fromInvalidate: " << static_cast<bool>(tokenData.fromInvalidate);
}
out << ", uuid: " << tokenData.uuid;
out << ", documentKey: " << tokenData.documentKey << "}";
return out;
}
ResumeToken::ResumeToken(const Document& resumeDoc) {
auto dataVal = resumeDoc[kDataFieldName];
uassert(40647,
str::stream()
<< "Bad resume token: _data of missing or of wrong type. Expected string, got "
<< resumeDoc.toString(),
dataVal.getType() == BSONType::String);
_hexKeyString = dataVal.getString();
_typeBits = resumeDoc[kTypeBitsFieldName];
uassert(40648,
str::stream() << "Bad resume token: _typeBits of wrong type " << resumeDoc.toString(),
_typeBits.missing() || (_typeBits.getType() == BSONType::BinData &&
_typeBits.getBinData().type == BinDataGeneral));
}
// We encode the resume token as a KeyString with the sequence:
// clusterTime, version, applyOpsIndex, fromInvalidate, uuid, documentKey
// Only the clusterTime, version, applyOpsIndex, and fromInvalidate are required.
ResumeToken::ResumeToken(const ResumeTokenData& data) {
BSONObjBuilder builder;
builder.append("", data.clusterTime);
builder.append("", data.version);
if (data.version >= 1) {
builder.appendNumber("", data.tokenType);
}
builder.appendNumber("", data.applyOpsIndex);
if (data.version >= 1) {
builder.appendBool("", data.fromInvalidate);
}
uassert(50788,
"Unexpected resume token with a documentKey but no UUID",
data.uuid || data.documentKey.missing());
if (data.uuid) {
data.uuid->appendToBuilder(&builder, "");
}
data.documentKey.addToBsonObj(&builder, "");
auto keyObj = builder.obj();
KeyString encodedToken(KeyString::Version::V1, keyObj, Ordering::make(BSONObj()));
_hexKeyString = toHex(encodedToken.getBuffer(), encodedToken.getSize());
const auto& typeBits = encodedToken.getTypeBits();
if (!typeBits.isAllZeros())
_typeBits = Value(
BSONBinData(typeBits.getBuffer(), typeBits.getSize(), BinDataType::BinDataGeneral));
}
bool ResumeToken::operator==(const ResumeToken& other) const {
// '_hexKeyString' is enough to determine equality. The type bits are used to unambiguously
// re-construct the original data, but we do not expect any two resume tokens to have the same
// data and different type bits, since that would imply they have (1) the same timestamp and (2)
// the same documentKey (possibly different types). This should not be possible because
// documents with the same documentKey should be on the same shard and therefore should have
// different timestamps.
return _hexKeyString == other._hexKeyString;
}
ResumeTokenData ResumeToken::getData() const {
KeyString::TypeBits typeBits(KeyString::Version::V1);
if (!_typeBits.missing()) {
BSONBinData typeBitsBinData = _typeBits.getBinData();
BufReader typeBitsReader(typeBitsBinData.data, typeBitsBinData.length);
typeBits.resetFromBuffer(&typeBitsReader);
}
uassert(ErrorCodes::FailedToParse,
"resume token string was not a valid hex string",
isValidHex(_hexKeyString));
BufBuilder hexDecodeBuf; // Keep this in scope until we've decoded the bytes.
fromHexString(_hexKeyString, &hexDecodeBuf);
BSONBinData keyStringBinData =
BSONBinData(hexDecodeBuf.buf(), hexDecodeBuf.len(), BinDataType::BinDataGeneral);
auto internalBson = KeyString::toBsonSafe(static_cast<const char*>(keyStringBinData.data),
keyStringBinData.length,
Ordering::make(BSONObj()),
typeBits);
BSONObjIterator i(internalBson);
ResumeTokenData result;
uassert(40649, "invalid empty resume token", i.more());
result.clusterTime = i.next().timestamp();
// Next comes the resume token version.
uassert(50796, "Resume Token does not contain version", i.more());
auto versionElt = i.next();
uassert(50854,
"Invalid resume token: wrong type for version",
versionElt.type() == BSONType::NumberInt);
result.version = versionElt.numberInt();
uassert(50795,
"Invalid Resume Token: only supports version 0 or 1",
result.version == 0 || result.version == 1);
if (result.version >= 1) {
// The 'tokenType' field was added in version 1 and is not present in v0 tokens.
uassert(51055, "Resume Token does not contain tokenType", i.more());
auto tokenType = i.next();
uassert(51056,
"Resume Token tokenType is not an int.",
tokenType.type() == BSONType::NumberInt);
auto typeInt = tokenType.numberInt();
uassert(51057,
str::stream() << "Token type " << typeInt << " not recognized",
typeInt == ResumeTokenData::TokenType::kEventToken ||
typeInt == ResumeTokenData::TokenType::kHighWaterMarkToken);
result.tokenType = static_cast<ResumeTokenData::TokenType>(typeInt);
}
// Next comes the applyOps index.
uassert(50793, "Resume Token does not contain applyOpsIndex", i.more());
auto applyOpsElt = i.next();
uassert(50855,
"Resume Token applyOpsIndex is not an integer",
applyOpsElt.type() == BSONType::NumberInt);
const int applyOpsInd = applyOpsElt.numberInt();
uassert(50794, "Invalid Resume Token: applyOpsIndex should be non-negative", applyOpsInd >= 0);
result.applyOpsIndex = applyOpsInd;
if (result.version >= 1) {
// The 'fromInvalidate' bool was added in version 1 resume tokens. We don't expect to see it
// on version 0 tokens. After this bool, the remaining fields should be the same.
uassert(50872, "Resume Token does not contain fromInvalidate", i.more());
auto fromInvalidate = i.next();
uassert(50870,
"Resume Token fromInvalidate is not a boolean.",
fromInvalidate.type() == BSONType::Bool);
result.fromInvalidate = ResumeTokenData::FromInvalidate(fromInvalidate.boolean());
}
// The UUID and documentKey are not required.
if (!i.more()) {
return result;
}
// The UUID comes first, then the documentKey.
result.uuid = uassertStatusOK(UUID::parse(i.next()));
if (i.more()) {
result.documentKey = Value(i.next());
}
uassert(40646, "invalid oversized resume token", !i.more());
return result;
}
Document ResumeToken::toDocument() const {
return Document{{kDataFieldName, _hexKeyString}, {kTypeBitsFieldName, _typeBits}};
}
ResumeToken ResumeToken::parse(const Document& resumeDoc) {
return ResumeToken(resumeDoc);
}
ResumeToken ResumeToken::makeHighWaterMarkToken(Timestamp clusterTime, boost::optional<UUID> uuid) {
return ResumeToken(makeHighWaterMarkResumeTokenData(clusterTime, uuid));
}
bool ResumeToken::isHighWaterMarkToken(const ResumeTokenData& tokenData) {
return tokenData == makeHighWaterMarkResumeTokenData(tokenData.clusterTime, tokenData.uuid);
}
} // namespace mongo
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