XLS-68: Sponsor

.config/cspell.config.yaml

@@ -216,6 +216,7 @@ words:
   - sles
   - soci
   - socidb
+  - sponsee
   - sslws
   - statsd
   - STATSDCOLLECTOR

include/xrpl/ledger/View.h

@@ -418,6 +418,63 @@ areCompatible(
     beast::Journal::Stream& s,
     char const* reason);
 
+uint32_t
+ownerCount(std::shared_ptr<SLE const> const& sponsorSle);
+
+XRPAmount
+calculateReserve(std::shared_ptr<SLE const> const& sle, Fees const& fees);
+
+bool
+isReserveSponsored(STTx const& tx);
+
+bool
+isSponsorReserveCoSigning(STTx const& tx);
+
+TER
+checkInsufficientReserve(
+    ReadView const& view,
+    STTx const& tx,
+    std::shared_ptr<SLE const> accSle,
+    STAmount const& accBalance,
+    std::shared_ptr<SLE const> const& sponsorSle,
+    std::int32_t ownerCountDelta,
+    std::int32_t accountCountDelta = 0);
+
+std::optional<AccountID>
+getTxReserveSponsorAccountID(STTx const& tx);
+
+std::shared_ptr<SLE>
+getTxReserveSponsor(ApplyView& view, STTx const& tx);
+
+std::shared_ptr<SLE const> const
+getTxReserveSponsor(ReadView const& view, STTx const& tx);
+
+std::optional<AccountID>
+getLedgerEntryReserveSponsorAccountID(
+    std::shared_ptr<SLE const> const& sle,
+    SF_ACCOUNT const& field = sfSponsorAccount);
+
+std::shared_ptr<SLE>
+getLedgerEntryReserveSponsor(
+    ApplyView& view,
+    std::shared_ptr<SLE> const& sle,
+    SF_ACCOUNT const& field = sfSponsorAccount);
+
+std::shared_ptr<SLE const> const
+getLedgerEntryReserveSponsor(
+    ReadView const& view,
+    std::shared_ptr<SLE const> const& sle,
+    SF_ACCOUNT const& field = sfSponsorAccount);
+
+void
+addSponsorToLedgerEntry(
+    std::shared_ptr<SLE> const& sle,
+    std::shared_ptr<SLE> const& sponsorSle,
+    SF_ACCOUNT const& field = sfSponsorAccount);
+
+void
+removeSponsorFromLedgerEntry(std::shared_ptr<SLE> const& sle, SF_ACCOUNT const& field = sfSponsorAccount);
+
 //------------------------------------------------------------------------------
 //
 // Modifiers
@@ -426,7 +483,42 @@ areCompatible(
 
 /** Adjust the owner count up or down. */
 void
-adjustOwnerCount(ApplyView& view, std::shared_ptr<SLE> const& sle, std::int32_t amount, beast::Journal j);
+adjustOwnerCount(
+    ApplyView& view,
+    std::shared_ptr<SLE> const& accountSle,
+    std::shared_ptr<SLE> const& sponsorSle,
+    std::int32_t amount,
+    beast::Journal j);
+
+inline void
+adjustOwnerCount(
+    ApplyView& view,
+    STTx const& tx,
+    std::shared_ptr<SLE> const& accountSle,
+    std::shared_ptr<SLE> const& sponsorSle,
+    std::int32_t amount,
+    beast::Journal j)
+{
+    adjustOwnerCount(view, accountSle, sponsorSle, amount, j);
+}
+
+inline void
+adjustOwnerCount(
+    ApplyView& view,
+    STTx const& tx,
+    AccountID const& account,
+    std::optional<AccountID> const& sponsor,
+    std::int32_t amount,
+    beast::Journal j)
+{
+    return adjustOwnerCount(
+        view,
+        tx,
+        view.peek(keylet::account(account)),
+        sponsor ? view.peek(keylet::account(*sponsor)) : std::shared_ptr<SLE>(),
+        amount,
+        j);
+}
 
 /** @{ */
 /** Returns the first entry in the directory, advancing the index
@@ -618,6 +710,7 @@ doWithdraw(
 [[nodiscard]] TER
 addEmptyHolding(
     ApplyView& view,
+    STTx const& tx,
     AccountID const& accountID,
     XRPAmount priorBalance,
     Issue const& issue,
@@ -626,6 +719,7 @@ addEmptyHolding(
 [[nodiscard]] TER
 addEmptyHolding(
     ApplyView& view,
+    STTx const& tx,
     AccountID const& accountID,
     XRPAmount priorBalance,
     MPTIssue const& mptIssue,
@@ -634,21 +728,23 @@ addEmptyHolding(
 [[nodiscard]] inline TER
 addEmptyHolding(
     ApplyView& view,
+    STTx const& tx,
     AccountID const& accountID,
     XRPAmount priorBalance,
     Asset const& asset,
     beast::Journal journal)
 {
     return std::visit(
         [&]<ValidIssueType TIss>(TIss const& issue) -> TER {
-            return addEmptyHolding(view, accountID, priorBalance, issue, journal);
+            return addEmptyHolding(view, tx, accountID, priorBalance, issue, journal);
         },
         asset.value());
 }
 
 [[nodiscard]] TER
 authorizeMPToken(
     ApplyView& view,
+    STTx const& tx,
     XRPAmount const& priorBalance,
     MPTID const& mptIssuanceID,
     AccountID const& account,
@@ -681,20 +777,36 @@ trustCreate(
                                 // Issuer should be the account being set.
     std::uint32_t uSrcQualityIn,
     std::uint32_t uSrcQualityOut,
+    std::optional<AccountID> const& sponsorAccountID,
     beast::Journal j);
 
 [[nodiscard]] TER
-removeEmptyHolding(ApplyView& view, AccountID const& accountID, Issue const& issue, beast::Journal journal);
+removeEmptyHolding(
+    ApplyView& view,
+    STTx const& tx,
+    AccountID const& accountID,
+    Issue const& issue,
+    beast::Journal journal);
 
 [[nodiscard]] TER
-removeEmptyHolding(ApplyView& view, AccountID const& accountID, MPTIssue const& mptIssue, beast::Journal journal);
+removeEmptyHolding(
+    ApplyView& view,
+    STTx const& tx,
+    AccountID const& accountID,
+    MPTIssue const& mptIssue,
+    beast::Journal journal);
 
 [[nodiscard]] inline TER
-removeEmptyHolding(ApplyView& view, AccountID const& accountID, Asset const& asset, beast::Journal journal)
+removeEmptyHolding(
+    ApplyView& view,
+    STTx const& tx,
+    AccountID const& accountID,
+    Asset const& asset,
+    beast::Journal journal)
 {
     return std::visit(
         [&]<ValidIssueType TIss>(TIss const& issue) -> TER {
-            return removeEmptyHolding(view, accountID, issue, journal);
+            return removeEmptyHolding(view, tx, accountID, issue, journal);
         },
         asset.value());
 }
@@ -763,6 +875,7 @@ accountSend(
     AccountID const& to,
     STAmount const& saAmount,
     beast::Journal j,
+    std::optional<AccountID> const& sponsorAcc = std::nullopt,
     WaiveTransferFee waiveFee = WaiveTransferFee::No);
 
 using MultiplePaymentDestinations = std::vector<std::pair<AccountID, Number>>;
@@ -779,6 +892,7 @@ accountSendMulti(
     Asset const& asset,
     MultiplePaymentDestinations const& receivers,
     beast::Journal j,
+    std::optional<AccountID> const& sponsorAccount,
     WaiveTransferFee waiveFee = WaiveTransferFee::No);
 
 [[nodiscard]] TER
@@ -889,6 +1003,7 @@ requireAuth(
 [[nodiscard]] TER
 enforceMPTokenAuthorization(
     ApplyView& view,
+    STTx const& tx,
     MPTID const& mptIssuanceID,
     AccountID const& account,
     XRPAmount const& priorBalance,

include/xrpl/protocol/Fees.h

@@ -27,9 +27,22 @@ struct Fees
         the reserve increment times the number of increments.
     */
     XRPAmount
-    accountReserve(std::size_t ownerCount) const
+    accountReserve(
+        std::size_t ownerCount,
+        std::size_t sponsoredOwnerCount = 0,
+        std::size_t sponsoringOwnerCount = 0,
+        bool isAccountSponsored = false,
+        std::size_t sponsoringAccountCount = 0) const
     {
-        return reserve + ownerCount * increment;
+        auto const accountReserveUnits = (isAccountSponsored ? 0 : 1) + sponsoringAccountCount;
+
+        XRPL_ASSERT(
+            ownerCount >= sponsoredOwnerCount,
+            "xrpl::Fees::accountReserve : OwnerCount must be greater than or equal to SponsoredOwnerCount");
+
+        auto const ownerReserveUnits = (ownerCount - sponsoredOwnerCount) + sponsoringOwnerCount;
+
+        return (reserve * accountReserveUnits) + (increment * ownerReserveUnits);
     }
 };
 

include/xrpl/protocol/Indexes.h

@@ -152,6 +152,10 @@ static ticket_t const ticket{};
 Keylet
 signers(AccountID const& account) noexcept;
 
+/** A Sponsor */
+Keylet
+sponsor(AccountID const& sponsor, AccountID const& sponsee) noexcept;
+
 /** A Check */
 /** @{ */
 Keylet

include/xrpl/protocol/LedgerFormats.h

@@ -130,6 +130,8 @@ enum LedgerSpecificFlags {
         0x40000000,               // True, enable trustline locking
     lsfAllowTrustLineClawback =
         0x80000000,               // True, enable clawback
+    lsfDisallowIncomingSponsor =
+        0x00004000,               // True, reject new sponsor
 
     // ltOFFER
     lsfPassive = 0x00010000,
@@ -191,6 +193,10 @@ enum LedgerSpecificFlags {
     lsfLoanDefault = 0x00010000,
     lsfLoanImpaired = 0x00020000,
     lsfLoanOverpayment = 0x00040000, // True, loan allows overpayments
+
+    // ltSPONSORSHIP
+    lsfSponsorshipRequireSignForFee     = 0x00010000,
+    lsfSponsorshipRequireSignForReserve = 0x00020000,
 };
 
 //------------------------------------------------------------------------------

include/xrpl/protocol/Sponsor.h

@@ -0,0 +1,20 @@
+#ifndef XRPL_PROTOCOL_SPONSOR_H_INCLUDED
+#define XRPL_PROTOCOL_SPONSOR_H_INCLUDED
+
+#include <xrpl/protocol/AccountID.h>
+#include <xrpl/protocol/HashPrefix.h>
+#include <xrpl/protocol/STVector256.h>
+#include <xrpl/protocol/Serializer.h>
+
+namespace xrpl {
+
+inline void
+addSerializeSponsorData(Serializer& msg, AccountID const& sponsorID, std::uint32_t const& flags)
+{
+    msg.addBitString(sponsorID);
+    msg.add32(flags);
+}
+
+}  // namespace xrpl
+
+#endif

include/xrpl/protocol/TER.h

@@ -209,6 +209,7 @@ enum TERcodes : TERUnderlyingType {
     terADDRESS_COLLISION,       // Failed to allocate AccountID when trying to
                                 // create a pseudo-account
     terNO_DELEGATE_PERMISSION,  // Delegate does not have permission
+    terNO_SPONSORSHIP,          // No sponsorship found
 };
 
 //------------------------------------------------------------------------------
@@ -347,6 +348,7 @@ enum TECcodes : TERUnderlyingType {
     // backward compatibility with historical data on non-prod networks, can be
     // reclaimed after those networks reset.
     tecNO_DELEGATE_PERMISSION = 198,
+    tecNO_SPONSOR_PERMISSION = 199,
 };
 
 //------------------------------------------------------------------------------

include/xrpl/protocol/TxFlags.h

@@ -43,6 +43,11 @@ constexpr std::uint32_t tfInnerBatchTxn                    = 0x40000000;
 constexpr std::uint32_t tfUniversal                        = tfFullyCanonicalSig | tfInnerBatchTxn;
 constexpr std::uint32_t tfUniversalMask                    = ~tfUniversal;
 
+// Sponsor flags (Global):
+constexpr std::uint32_t tfSponsorFee                       = 0x00000001;
+constexpr std::uint32_t tfSponsorReserve                   = 0x00000002;
+constexpr std::uint32_t tfSponsorMask                      = ~(tfSponsorFee | tfSponsorReserve);
+
 // AccountSet flags:
 constexpr std::uint32_t tfRequireDestTag                   = 0x00010000;
 constexpr std::uint32_t tfOptionalDestTag                  = 0x00020000;
@@ -74,6 +79,7 @@ constexpr std::uint32_t asfDisallowIncomingPayChan         = 14;
 constexpr std::uint32_t asfDisallowIncomingTrustline       = 15;
 constexpr std::uint32_t asfAllowTrustLineClawback          = 16;
 constexpr std::uint32_t asfAllowTrustLineLocking           = 17;
+constexpr std::uint32_t asfDisallowIncomingSponsor         = 19;
 
 // OfferCreate flags:
 constexpr std::uint32_t tfPassive                          = 0x00010000;
@@ -88,8 +94,9 @@ constexpr std::uint32_t tfOfferCreateMask =
 constexpr std::uint32_t tfNoRippleDirect                   = 0x00010000;
 constexpr std::uint32_t tfPartialPayment                   = 0x00020000;
 constexpr std::uint32_t tfLimitQuality                     = 0x00040000;
+constexpr std::uint32_t tfSponsorCreatedAccount            = 0x00080000;
 constexpr std::uint32_t tfPaymentMask =
-    ~(tfUniversal | tfPartialPayment | tfLimitQuality | tfNoRippleDirect);
+    ~(tfUniversal | tfPartialPayment | tfLimitQuality | tfNoRippleDirect | tfSponsorCreatedAccount);
 constexpr std::uint32_t tfMPTPaymentMask = ~(tfUniversal | tfPartialPayment);
 
 // TrustSet flags:
@@ -292,6 +299,15 @@ constexpr std::uint32_t const tfLoanImpair = 0x00020000;
 constexpr std::uint32_t const tfLoanUnimpair = 0x00040000;
 constexpr std::uint32_t const tfLoanManageMask = ~(tfUniversal | tfLoanDefault | tfLoanImpair | tfLoanUnimpair);
 
+// SponsorshipSet flags:
+constexpr std::uint32_t tfSponsorshipSetRequireSignForFee                    = 0x00010000;
+constexpr std::uint32_t tfSponsorshipClearRequireSignForFee                  = 0x00020000;
+constexpr std::uint32_t tfSponsorshipSetRequireSignForReserve                = 0x00040000;
+constexpr std::uint32_t tfSponsorshipClearRequireSignForReserve              = 0x00080000;
+constexpr std::uint32_t tfDeleteObject                                       = 0x00100000;
+constexpr std::uint32_t tfSponsorshipSetMask = ~(tfUniversal | tfSponsorshipSetRequireSignForFee | tfSponsorshipClearRequireSignForFee | tfSponsorshipSetRequireSignForReserve | tfSponsorshipClearRequireSignForReserve | tfDeleteObject);
+constexpr std::uint32_t tfSponsorshipSetPermissionMask = ~(tfUniversal | tfSponsorshipSetRequireSignForFee | tfSponsorshipSetRequireSignForReserve);
+
 // clang-format on
 
 }  // namespace xrpl

include/xrpl/protocol/detail/features.macro

@@ -16,6 +16,7 @@
 // Add new amendments to the top of this list.
 // Keep it sorted in reverse chronological order.
 
+XRPL_FEATURE(Sponsor,                    Supported::no,  VoteBehavior::DefaultNo)
 XRPL_FIX    (BatchInnerSigs,             Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FEATURE(LendingProtocol,            Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FEATURE(PermissionDelegationV1_1,   Supported::no,  VoteBehavior::DefaultNo)