Strongly Typed wrapper for Negative UNL ledger object

src/ripple/app/ledger/Ledger.cpp

@@ -712,10 +712,10 @@ hash_set<PublicKey>
 Ledger::negativeUNL() const
 {
     hash_set<PublicKey> negUnl;
-    if (auto sle = readSLE(keylet::negativeUNL());
-        sle && sle->isFieldPresent(sfDisabledValidators))
+    if (auto nUNLLedgerObj = read(keylet::negativeUNL());
+        nUNLLedgerObj && nUNLLedgerObj->isFieldPresent(sfDisabledValidators)) // Keshava: Can we avoid these expensive conversions into ->slePtr()
     {
-        auto const& nUnlData = sle->getFieldArray(sfDisabledValidators);
+        auto const& nUnlData = nUNLLedgerObj->getFieldArray(sfDisabledValidators);
         for (auto const& n : nUnlData)
         {
             if (n.isFieldPresent(sfPublicKey))
@@ -737,10 +737,10 @@ Ledger::negativeUNL() const
 std::optional<PublicKey>
 Ledger::validatorToDisable() const
 {
-    if (auto sle = readSLE(keylet::negativeUNL());
-        sle && sle->isFieldPresent(sfValidatorToDisable))
+    if (auto nUNLLedgerObj = read<NegUNLKeylet, NegUNLRd>(keylet::negativeUNL());
+        nUNLLedgerObj && nUNLLedgerObj->isFieldPresent(sfValidatorToDisable))
     {
-        auto d = sle->getFieldVL(sfValidatorToDisable);
+        auto d = nUNLLedgerObj->getFieldVL(sfValidatorToDisable);
         auto s = makeSlice(d);
         if (publicKeyType(s))
             return PublicKey(s);

src/ripple/app/tx/impl/Change.cpp

@@ -425,11 +425,11 @@ Change::applyUNLModify()
                     << " validator data:" << strHex(validator);
 
     auto const k = keylet::negativeUNL();
-    SLE::pointer negUnlObject = view().peekSLE(k);
+    std::optional<NegUNL> negUnlObject = view().peek(k);
     if (!negUnlObject)
     {
-        negUnlObject = std::make_shared<SLE>(k);
-        view().insert(negUnlObject);
+        negUnlObject = NegUNL(std::make_shared<SLE>(k));
+        view().insert(negUnlObject->slePtr());
     }
 
     bool const found = [&] {
@@ -508,7 +508,7 @@ Change::applyUNLModify()
         negUnlObject->setFieldVL(sfValidatorToReEnable, validator);
     }
 
-    view().update(negUnlObject);
+    view().update(*negUnlObject);
     return tesSUCCESS;
 }
 

src/ripple/protocol/Indexes.h

@@ -87,7 +87,7 @@ Keylet const&
 fees() noexcept;
 
 /** The (fixed) index of the object containing the ledger negativeUNL. */
-Keylet const&
+NegUNLKeylet const&
 negativeUNL() noexcept;
 
 /** The beginning of an order book */

src/ripple/protocol/Keylet.h

@@ -23,6 +23,7 @@
 #include <ripple/basics/base_uint.h>
 #include <ripple/protocol/AcctRoot.h>
 #include <ripple/protocol/LedgerFormats.h>
+#include <ripple/protocol/NegativeUNL.h>
 
 namespace ripple {
 
@@ -95,6 +96,22 @@ static_assert(std::is_move_assignable_v<Keylet>);
 static_assert(std::is_nothrow_destructible_v<Keylet>);
 #endif
 
+template <bool>
+class NegUNLImpl;
+
+struct NegUNLKeylet final : public KeyletBase
+{
+    template <bool Writable>
+    using TWrapped = NegUNLImpl<Writable>;
+
+    using KeyletBase::check;
+
+    explicit NegUNLKeylet(uint256 const& key)
+        : KeyletBase(ltNEGATIVE_UNL, key)
+    {
+    }
+};
+
 template <bool>
 class AcctRootImpl;
 

src/ripple/protocol/NegativeUNL.h

@@ -0,0 +1,92 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2021 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 RIPPLE_PROTOCOL_NEGATIVE_UNL_H_INCLUDED
+#define RIPPLE_PROTOCOL_NEGATIVE_UNL_H_INCLUDED
+
+#include <ripple/protocol/LedgerEntryWrapper.h>
+//#include <ripple/protocol/STAccount.h>
+//#include <ripple/protocol/STAmount.h>
+
+namespace ripple {
+
+template <bool Writable>
+class NegUNLImpl final : public LedgerEntryWrapper<Writable>
+{
+private:
+    using Base = LedgerEntryWrapper<Writable>;
+    using SleT = typename Base::SleT;
+    using Base::wrapped_;
+
+
+    // Friend declarations of factory functions.
+    //
+    // For classes that contain factories we must declare the entire class
+    // as a friend unless the class declaration is visible at this point.
+    friend class ReadView;
+    friend class ApplyView;
+
+public:
+    // This constructor is used in Change::applyUNLModify() function.
+    // Keshava: Is it mandatory to use make_XYZ factory functions for this usecase?
+    // What are the perils of having a public constructor?
+    NegUNLImpl(std::shared_ptr<SleT>&& w) : Base(std::move(w))
+    {
+    }
+
+    // Conversion operator from NegUNLImpl<true> to NegUNLImpl<false>.
+    operator NegUNLImpl<true>() const
+    {
+        return NegUNLImpl<false>(
+            std::const_pointer_cast<std::shared_ptr<STLedgerEntry const>>(
+                wrapped_));
+    }
+
+    [[nodiscard]] bool
+        isFieldPresent(SField const& field) const {
+        return wrapped_->isFieldPresent(field);
+    }
+
+    [[nodiscard]] Blob
+    getFieldVL(SField const& field) const {
+        return wrapped_->getFieldVL(field);
+    }
+
+    void
+    setFieldVL(SField const& field, Slice const& sl) const {
+        return wrapped_->setFieldVL(field, sl);
+    }
+
+    void
+    setFieldVL(SField const& field, Blob const& blob) const {
+        return wrapped_->setFieldVL(field, blob);
+    }
+
+    [[nodiscard]] const auto&
+    getFieldArray(SField const& field) const {
+        return wrapped_->getFieldArray(field);
+    }
+};
+
+using NegUNL = NegUNLImpl<true>;
+using NegUNLRd = NegUNLImpl<false>;
+
+}  // namespace ripple
+
+#endif  // RIPPLE_PROTOCOL_NEGATIVE_UNL_H_INCLUDED

src/ripple/protocol/impl/Indexes.cpp

@@ -175,11 +175,10 @@ fees() noexcept
     return ret;
 }
 
-Keylet const&
+NegUNLKeylet const&
 negativeUNL() noexcept
 {
-    static Keylet const ret{
-        ltNEGATIVE_UNL, indexHash(LedgerNameSpace::NEGATIVE_UNL)};
+    static NegUNLKeylet const ret(indexHash(LedgerNameSpace::NEGATIVE_UNL));
     return ret;
 }