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Add a new serialized type: STNumber (#5121)

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`STNumber` lets objects and transactions contain multiple fields for
quantities of XRP, IOU, or MPT without duplicating information about the
"issue" (represented by `STIssue`). It is a straightforward serialization of
the `Number` type that uniformly represents those quantities.

---------

Co-authored-by: John Freeman <jfreeman08@gmail.com>
Co-authored-by: Howard Hinnant <howard.hinnant@gmail.com>
This commit is contained in:
Elliot Lee
2024-11-25 12:12:35 -08:00
parent 0ec17b6026
commit f419c18056
15 changed files with 470 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
include/xrpl/basics/Number.h
View File

@@ -41,6 +41,14 @@ class Number
int exponent_{std::numeric_limits<int>::lowest()};
public:
// The range for the mantissa when normalized
constexpr static std::int64_t minMantissa = 1'000'000'000'000'000LL;
constexpr static std::int64_t maxMantissa = 9'999'999'999'999'999LL;
// The range for the exponent when normalized
constexpr static int minExponent = -32768;
constexpr static int maxExponent = 32768;
struct unchecked
{
explicit unchecked() = default;
@@ -191,14 +199,6 @@ private:
constexpr bool
isnormal() const noexcept;
// The range for the mantissa when normalized
constexpr static std::int64_t minMantissa = 1'000'000'000'000'000LL;
constexpr static std::int64_t maxMantissa = 9'999'999'999'999'999LL;
// The range for the exponent when normalized
constexpr static int minExponent = -32768;
constexpr static int maxExponent = 32768;
class Guard;
};

5
include/xrpl/protocol/SField.h
View File

@@ -49,6 +49,7 @@ template <int>
class STBitString;
template <class>
class STInteger;
class STNumber;
class STXChainBridge;
class STVector256;
class STCurrency;
@@ -70,8 +71,9 @@ class STCurrency;
STYPE(STI_AMOUNT, 6) \
STYPE(STI_VL, 7) \
STYPE(STI_ACCOUNT, 8) \
STYPE(STI_NUMBER, 9) \
\
/* 9-13 are reserved */ \
/* 10-13 are reserved */ \
STYPE(STI_OBJECT, 14) \
STYPE(STI_ARRAY, 15) \
\
@@ -355,6 +357,7 @@ using SF_ACCOUNT = TypedField<STAccount>;
using SF_AMOUNT = TypedField<STAmount>;
using SF_ISSUE = TypedField<STIssue>;
using SF_CURRENCY = TypedField<STCurrency>;
using SF_NUMBER = TypedField<STNumber>;
using SF_VL = TypedField<STBlob>;
using SF_VECTOR256 = TypedField<STVector256>;
using SF_XCHAIN_BRIDGE = TypedField<STXChainBridge>;

88
include/xrpl/protocol/STNumber.h Normal file
View File

@@ -0,0 +1,88 @@
//------------------------------------------------------------------------------
/*
This file is part of rippled: https://github.com/ripple/rippled
Copyright (c) 2024 Ripple Labs Inc.
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#ifndef XRPL_PROTOCOL_STNUMBER_H_INCLUDED
#define XRPL_PROTOCOL_STNUMBER_H_INCLUDED
#include <xrpl/basics/CountedObject.h>
#include <xrpl/basics/Number.h>
#include <xrpl/protocol/STBase.h>
#include <ostream>
namespace ripple {
/**
* A serializable number.
*
* This type is-a `Number`, and can be used everywhere that is accepted.
* This type simply integrates `Number` with the serialization framework,
* letting it be used for fields in ledger entries and transactions.
* It is effectively an `STAmount` sans `Asset`:
* it can represent a value of any token type (XRP, IOU, or MPT)
* without paying the storage cost of duplicating asset information
* that may be deduced from the context.
*/
class STNumber : public STBase, public CountedObject<STNumber>
{
private:
Number value_;
public:
using value_type = Number;
STNumber() = default;
explicit STNumber(SField const& field, Number const& value = Number());
STNumber(SerialIter& sit, SField const& field);
SerializedTypeID
getSType() const override;
std::string
getText() const override;
void
add(Serializer& s) const override;
Number const&
value() const;
void
setValue(Number const& v);
bool
isEquivalent(STBase const& t) const override;
bool
isDefault() const override;
operator Number() const
{
return value_;
}
private:
STBase*
copy(std::size_t n, void* buf) const override;
STBase*
move(std::size_t n, void* buf) override;
};
std::ostream&
operator<<(std::ostream& out, STNumber const& rhs);
} // namespace ripple
#endif

4
include/xrpl/protocol/STObject.h
View File

@@ -245,6 +245,8 @@ public:
getFieldArray(SField const& field) const;
const STCurrency&
getFieldCurrency(SField const& field) const;
STNumber const&
getFieldNumber(SField const& field) const;
/** Get the value of a field.
@param A TypedField built from an SField value representing the desired
@@ -376,6 +378,8 @@ public:
void
setFieldCurrency(SField const& field, STCurrency const&);
void
setFieldNumber(SField const& field, STNumber const&);
void
setFieldPathSet(SField const& field, STPathSet const&);
void
setFieldV256(SField const& field, STVector256 const& v);

39
include/xrpl/protocol/Serializer.h
View File

@@ -83,12 +83,43 @@ public:
add8(unsigned char i);
int
add16(std::uint16_t i);
template <typename T>
requires(std::is_same_v<
std::make_unsigned_t<std::remove_cv_t<T>>,
std::uint32_t>)
int
add32(std::uint32_t i); // ledger indexes, account sequence, timestamps
add32(T i)
{
int ret = mData.size();
mData.push_back(static_cast<unsigned char>((i >> 24) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 16) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 8) & 0xff));
mData.push_back(static_cast<unsigned char>(i & 0xff));
return ret;
}
int
add32(HashPrefix p);
template <typename T>
requires(std::is_same_v<
std::make_unsigned_t<std::remove_cv_t<T>>,
std::uint64_t>)
int
add64(std::uint64_t i); // native currency amounts
add64(T i)
{
int ret = mData.size();
mData.push_back(static_cast<unsigned char>((i >> 56) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 48) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 40) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 32) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 24) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 16) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 8) & 0xff));
mData.push_back(static_cast<unsigned char>(i & 0xff));
return ret;
}
template <typename Integer>
int addInteger(Integer);
@@ -353,9 +384,13 @@ public:
std::uint32_t
get32();
std::int32_t
geti32();
std::uint64_t
get64();
std::int64_t
geti64();
template <std::size_t Bits, class Tag = void>
base_uint<Bits, Tag>

3
include/xrpl/protocol/detail/sfields.macro
View File

@@ -191,6 +191,9 @@ TYPED_SFIELD(sfHookHash, UINT256, 31)
TYPED_SFIELD(sfHookNamespace, UINT256, 32)
TYPED_SFIELD(sfHookSetTxnID, UINT256, 33)
// number (common)
TYPED_SFIELD(sfNumber, NUMBER, 1)
// currency amount (common)
TYPED_SFIELD(sfAmount, AMOUNT, 1)
TYPED_SFIELD(sfBalance, AMOUNT, 2)

1
include/xrpl/protocol/st.h
View File

@@ -29,6 +29,7 @@
#include <xrpl/protocol/STBlob.h>
#include <xrpl/protocol/STInteger.h>
#include <xrpl/protocol/STLedgerEntry.h>
#include <xrpl/protocol/STNumber.h>
#include <xrpl/protocol/STObject.h>
#include <xrpl/protocol/STParsedJSON.h>
#include <xrpl/protocol/STPathSet.h>

105
src/libxrpl/protocol/STNumber.cpp Normal file
View File

@@ -0,0 +1,105 @@
//------------------------------------------------------------------------------
/*
This file is part of rippled: https://github.com/ripple/rippled
Copyright (c) 2023 Ripple Labs Inc.
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#include <xrpl/protocol/STNumber.h>
#include <xrpl/protocol/SField.h>
namespace ripple {
STNumber::STNumber(SField const& field, Number const& value)
: STBase(field), value_(value)
{
}
STNumber::STNumber(SerialIter& sit, SField const& field) : STBase(field)
{
// We must call these methods in separate statements
// to guarantee their order of execution.
auto mantissa = sit.geti64();
auto exponent = sit.geti32();
value_ = Number{mantissa, exponent};
}
SerializedTypeID
STNumber::getSType() const
{
return STI_NUMBER;
}
std::string
STNumber::getText() const
{
return to_string(value_);
}
void
STNumber::add(Serializer& s) const
{
assert(getFName().isBinary());
assert(getFName().fieldType == getSType());
s.add64(value_.mantissa());
s.add32(value_.exponent());
}
Number const&
STNumber::value() const
{
return value_;
}
void
STNumber::setValue(Number const& v)
{
value_ = v;
}
STBase*
STNumber::copy(std::size_t n, void* buf) const
{
return emplace(n, buf, *this);
}
STBase*
STNumber::move(std::size_t n, void* buf)
{
return emplace(n, buf, std::move(*this));
}
bool
STNumber::isEquivalent(STBase const& t) const
{
assert(t.getSType() == this->getSType());
STNumber const& v = dynamic_cast<STNumber const&>(t);
return value_ == v;
}
bool
STNumber::isDefault() const
{
return value_ == Number();
}
std::ostream&
operator<<(std::ostream& out, STNumber const& rhs)
{
return out << rhs.getText();
}
} // namespace ripple

14
src/libxrpl/protocol/STObject.cpp
View File

@@ -25,6 +25,7 @@
#include <xrpl/protocol/STArray.h>
#include <xrpl/protocol/STBlob.h>
#include <xrpl/protocol/STCurrency.h>
#include <xrpl/protocol/STNumber.h>
#include <xrpl/protocol/STObject.h>
namespace ripple {
@@ -665,6 +666,13 @@ STObject::getFieldCurrency(SField const& field) const
return getFieldByConstRef<STCurrency>(field, empty);
}
STNumber const&
STObject::getFieldNumber(SField const& field) const
{
static STNumber const empty{};
return getFieldByConstRef<STNumber>(field, empty);
}
void
STObject::set(std::unique_ptr<STBase> v)
{
@@ -765,6 +773,12 @@ STObject::setFieldIssue(SField const& field, STIssue const& v)
setFieldUsingAssignment(field, v);
}
void
STObject::setFieldNumber(SField const& field, STNumber const& v)
{
setFieldUsingAssignment(field, v);
}
void
STObject::setFieldPathSet(SField const& field, STPathSet const& v)
{

1
src/libxrpl/protocol/STVar.cpp
View File

@@ -29,6 +29,7 @@
#include <xrpl/protocol/STCurrency.h>
#include <xrpl/protocol/STInteger.h>
#include <xrpl/protocol/STIssue.h>
#include <xrpl/protocol/STNumber.h>
#include <xrpl/protocol/STObject.h>
#include <xrpl/protocol/STPathSet.h>
#include <xrpl/protocol/STVector256.h>

51
src/libxrpl/protocol/Serializer.cpp
View File

@@ -21,6 +21,7 @@
#include <xrpl/basics/contract.h>
#include <xrpl/protocol/Serializer.h>
#include <xrpl/protocol/digest.h>
#include <cstdint>
#include <type_traits>
namespace ripple {
@@ -34,17 +35,6 @@ Serializer::add16(std::uint16_t i)
return ret;
}
int
Serializer::add32(std::uint32_t i)
{
int ret = mData.size();
mData.push_back(static_cast<unsigned char>(i >> 24));
mData.push_back(static_cast<unsigned char>((i >> 16) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 8) & 0xff));
mData.push_back(static_cast<unsigned char>(i & 0xff));
return ret;
}
int
Serializer::add32(HashPrefix p)
{
@@ -56,21 +46,6 @@ Serializer::add32(HashPrefix p)
return add32(safe_cast<std::uint32_t>(p));
}
int
Serializer::add64(std::uint64_t i)
{
int ret = mData.size();
mData.push_back(static_cast<unsigned char>(i >> 56));
mData.push_back(static_cast<unsigned char>((i >> 48) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 40) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 32) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 24) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 16) & 0xff));
mData.push_back(static_cast<unsigned char>((i >> 8) & 0xff));
mData.push_back(static_cast<unsigned char>(i & 0xff));
return ret;
}
template <>
int
Serializer::addInteger(unsigned char i)
@@ -410,6 +385,30 @@ SerialIter::get64()
(std::uint64_t(t[6]) << 8) + std::uint64_t(t[7]);
}
std::int32_t
SerialIter::geti32()
{
if (remain_ < 4)
Throw<std::runtime_error>("invalid SerialIter geti32");
auto t = p_;
p_ += 4;
used_ += 4;
remain_ -= 4;
return boost::endian::load_big_s32(t);
}
std::int64_t
SerialIter::geti64()
{
if (remain_ < 8)
Throw<std::runtime_error>("invalid SerialIter geti64");
auto t = p_;
p_ += 8;
used_ += 8;
remain_ -= 8;
return boost::endian::load_big_s64(t);
}
void
SerialIter::getFieldID(int& type, int& name)
{

93
src/test/protocol/STNumber_test.cpp Normal file
View File

@@ -0,0 +1,93 @@
//------------------------------------------------------------------------------
/*
This file is part of rippled: https://github.com/ripple/rippled
Copyright (c) 2024 Ripple Labs Inc.
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#include <xrpl/beast/unit_test.h>
#include <xrpl/protocol/Issue.h>
#include <xrpl/protocol/STAmount.h>
#include <xrpl/protocol/STNumber.h>
#include <limits>
#include <ostream>
namespace ripple {
struct STNumber_test : public beast::unit_test::suite
{
void
testCombo(Number number)
{
STNumber const before{sfNumber, number};
BEAST_EXPECT(number == before);
Serializer s;
before.add(s);
BEAST_EXPECT(s.size() == 12);
SerialIter sit(s.slice());
STNumber const after{sit, sfNumber};
BEAST_EXPECT(after.isEquivalent(before));
BEAST_EXPECT(number == after);
}
void
run() override
{
static_assert(!std::is_convertible_v<STNumber*, Number*>);
{
STNumber const stnum{sfNumber};
BEAST_EXPECT(stnum.getSType() == STI_NUMBER);
BEAST_EXPECT(stnum.getText() == "0");
BEAST_EXPECT(stnum.isDefault() == true);
BEAST_EXPECT(stnum.value() == Number{0});
}
std::initializer_list<std::int64_t> const mantissas = {
std::numeric_limits<std::int64_t>::min(),
-1,
0,
1,
std::numeric_limits<std::int64_t>::max()};
for (std::int64_t mantissa : mantissas)
testCombo(Number{mantissa});
std::initializer_list<std::int32_t> const exponents = {
Number::minExponent, -1, 0, 1, Number::maxExponent - 1};
for (std::int32_t exponent : exponents)
testCombo(Number{123, exponent});
{
STAmount const strikePrice{noIssue(), 100};
STNumber const factor{sfNumber, 100};
auto const iouValue = strikePrice.iou();
IOUAmount totalValue{iouValue * factor};
STAmount const totalAmount{totalValue, strikePrice.issue()};
BEAST_EXPECT(totalAmount == Number{10'000});
}
}
};
BEAST_DEFINE_TESTSUITE(STNumber, protocol, ripple);
void
testCompile(std::ostream& out)
{
STNumber number{sfNumber, 42};
out << number;
}
} // namespace ripple

69
src/test/protocol/Serializer_test.cpp Normal file
View File

@@ -0,0 +1,69 @@
//------------------------------------------------------------------------------
/*
This file is part of rippled: https://github.com/ripple/rippled
Copyright (c) 2024 Ripple Labs Inc.
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#include <xrpl/beast/unit_test.h>
#include <xrpl/protocol/Serializer.h>
#include <limits>
namespace ripple {
struct Serializer_test : public beast::unit_test::suite
{
void
run() override
{
{
std::initializer_list<std::int32_t> const values = {
std::numeric_limits<std::int32_t>::min(),
-1,
0,
1,
std::numeric_limits<std::int32_t>::max()};
for (std::int32_t value : values)
{
Serializer s;
s.add32(value);
BEAST_EXPECT(s.size() == 4);
SerialIter sit(s.slice());
BEAST_EXPECT(sit.geti32() == value);
}
}
{
std::initializer_list<std::int64_t> const values = {
std::numeric_limits<std::int64_t>::min(),
-1,
0,
1,
std::numeric_limits<std::int64_t>::max()};
for (std::int64_t value : values)
{
Serializer s;
s.add64(value);
BEAST_EXPECT(s.size() == 8);
SerialIter sit(s.slice());
BEAST_EXPECT(sit.geti64() == value);
}
}
}
};
BEAST_DEFINE_TESTSUITE(Serializer, protocol, ripple);
} // namespace ripple

18
src/xrpld/app/tx/detail/Payment.cpp
View File

@@ -88,7 +88,7 @@ Payment::preflight(PreflightContext const& ctx)
if (txFlags & paymentMask)
{
JLOG(j.trace()) << "Malformed transaction: " << "Invalid flags set.";
JLOG(j.trace()) << "Malformed transaction: Invalid flags set.";
return temINVALID_FLAG;
}
@@ -110,9 +110,9 @@ Payment::preflight(PreflightContext const& ctx)
if ((mptDirect && dstAmount.asset() != maxSourceAmount.asset()) ||
(!mptDirect && maxSourceAmount.holds<MPTIssue>()))
{
JLOG(j.trace()) << "Malformed transaction: "
<< "inconsistent issues: " << dstAmount.getFullText()
<< " " << maxSourceAmount.getFullText() << " "
JLOG(j.trace()) << "Malformed transaction: inconsistent issues: "
<< dstAmount.getFullText() << " "
<< maxSourceAmount.getFullText() << " "
<< deliverMin.value_or(STAmount{}).getFullText();
return temMALFORMED;
}
@@ -135,19 +135,19 @@ Payment::preflight(PreflightContext const& ctx)
}
if (hasMax && maxSourceAmount <= beast::zero)
{
JLOG(j.trace()) << "Malformed transaction: " << "bad max amount: "
JLOG(j.trace()) << "Malformed transaction: bad max amount: "
<< maxSourceAmount.getFullText();
return temBAD_AMOUNT;
}
if (dstAmount <= beast::zero)
{
JLOG(j.trace()) << "Malformed transaction: "
<< "bad dst amount: " << dstAmount.getFullText();
JLOG(j.trace()) << "Malformed transaction: bad dst amount: "
<< dstAmount.getFullText();
return temBAD_AMOUNT;
}
if (badCurrency() == srcAsset || badCurrency() == dstAsset)
{
JLOG(j.trace()) << "Malformed transaction: " << "Bad currency.";
JLOG(j.trace()) << "Malformed transaction: Bad currency.";
return temBAD_CURRENCY;
}
if (account == dstAccountID && equalTokens(srcAsset, dstAsset) && !hasPaths)
@@ -550,7 +550,7 @@ Payment::doApply()
// Vote no. However the transaction might succeed, if applied in
// a different order.
JLOG(j_.trace()) << "Delay transaction: Insufficient funds: "
<< " " << to_string(mPriorBalance) << " / "
<< to_string(mPriorBalance) << " / "
<< to_string(dstAmount.xrp() + mmm) << " ("
<< to_string(reserve) << ")";

21
src/xrpld/ledger/detail/CachedView.cpp
View File

@@ -63,20 +63,17 @@ CachedViewImpl::read(Keylet const& k) const
hits.increment();
else
misses.increment();
std::lock_guard lock(mutex_);
auto const er = map_.emplace(k.key, *digest);
bool const inserted = er.second;
if (sle && !k.check(*sle))
if (!cacheHit)
{
if (!inserted)
{
// On entry, this function did not find this key in map_. Now
// something (another thread?) has inserted the sle into the map and
// it has the wrong type.
LogicError("CachedView::read: wrong type");
}
return nullptr;
// Avoid acquiring this lock unless necessary. It is only necessary if
// the key was not found in the map_. The lock is needed to add the key
// and digest.
std::lock_guard lock(mutex_);
map_.emplace(k.key, *digest);
}
if (!sle || !k.check(*sle))
return nullptr;
return sle;
}