XLS-68: Sponsor

include/xrpl/ledger/View.h

@@ -432,6 +432,62 @@ areCompatible(
     beast::Journal::Stream& s,
     char const* reason);
 
+uint32_t
+ownerCount(std::shared_ptr<SLE const> const& sponsorSle);
+
+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::optional<std::shared_ptr<SLE const>> const& sponsorSle,
+    std::int32_t ownerCountDelta,
+    std::int32_t accountCountDelta = 0);
+
+std::optional<AccountID>
+getTxReserveSponsorAccountID(STTx const& tx);
+
+std::optional<std::shared_ptr<SLE>>
+getTxReserveSponsor(ApplyView& view, STTx const& tx);
+
+std::optional<std::shared_ptr<SLE const>>
+getTxReserveSponsor(ReadView const& view, STTx const& tx);
+
+std::optional<AccountID>
+getLedgerEntryReserveSponsorAccountID(
+    std::shared_ptr<SLE const> sle,
+    SF_ACCOUNT const& field = sfSponsorAccount);
+
+std::optional<std::shared_ptr<SLE>>
+getLedgerEntryReserveSponsor(
+    ApplyView& view,
+    std::shared_ptr<SLE> sle,
+    SF_ACCOUNT const& field = sfSponsorAccount);
+
+std::optional<std::shared_ptr<SLE const>>
+getLedgerEntryReserveSponsor(
+    ReadView const& view,
+    std::shared_ptr<SLE const> sle,
+    SF_ACCOUNT const& field = sfSponsorAccount);
+
+void
+addSponsorToLedgerEntry(
+    std::shared_ptr<SLE> const& sle,
+    std::optional<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
@@ -442,10 +498,42 @@ areCompatible(
 void
 adjustOwnerCount(
     ApplyView& view,
-    std::shared_ptr<SLE> const& sle,
+    std::shared_ptr<SLE> const& accountSle,
+    std::optional<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::optional<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::optional<std::shared_ptr<SLE>>(),
+        amount,
+        j);
+}
+
 /** @{ */
 /** Returns the first entry in the directory, advancing the index
 
@@ -567,6 +655,7 @@ canAddHolding(ReadView const& view, Asset const& asset);
 [[nodiscard]] TER
 addEmptyHolding(
     ApplyView& view,
+    STTx const& tx,
     AccountID const& accountID,
     XRPAmount priorBalance,
     Issue const& issue,
@@ -575,6 +664,7 @@ addEmptyHolding(
 [[nodiscard]] TER
 addEmptyHolding(
     ApplyView& view,
+    STTx const& tx,
     AccountID const& accountID,
     XRPAmount priorBalance,
     MPTIssue const& mptIssue,
@@ -583,6 +673,7 @@ addEmptyHolding(
 [[nodiscard]] inline TER
 addEmptyHolding(
     ApplyView& view,
+    STTx const& tx,
     AccountID const& accountID,
     XRPAmount priorBalance,
     Asset const& asset,
@@ -591,14 +682,15 @@ addEmptyHolding(
     return std::visit(
         [&]<ValidIssueType TIss>(TIss const& issue) -> TER {
             return addEmptyHolding(
-                view, accountID, priorBalance, issue, journal);
+                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,
@@ -631,32 +723,37 @@ trustCreate(
                                 // Issuer should be the account being set.
     std::uint32_t uSrcQualityIn,
     std::uint32_t uSrcQualityOut,
+    std::optional<AccountID> const& sponsorAccountID,
+    bool const isSponsorCoSigning,
     beast::Journal j);
 
 [[nodiscard]] TER
 removeEmptyHolding(
     ApplyView& view,
+    STTx const& tx,
     AccountID const& accountID,
     Issue const& issue,
     beast::Journal journal);
 
 [[nodiscard]] TER
 removeEmptyHolding(
     ApplyView& view,
+    STTx const& tx,
     AccountID const& accountID,
     MPTIssue const& mptIssue,
     beast::Journal journal);
 
 [[nodiscard]] inline TER
 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());
 }
@@ -729,6 +826,8 @@ accountSend(
     AccountID const& to,
     STAmount const& saAmount,
     beast::Journal j,
+    std::optional<AccountID> const& sponsorAcc = std::nullopt,
+    bool isSponsorCoSigning = false,
     WaiveTransferFee waiveFee = WaiveTransferFee::No);
 
 [[nodiscard]] TER
@@ -859,6 +958,7 @@ 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 +27,17 @@
         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;
+        return (isAccountSponsored ? XRPAmount(0) : reserve) +
+            increment *
+            (ownerCount + sponsoringOwnerCount - sponsoredOwnerCount) +
+            reserve * sponsoringAccountCount;
     }
 };
 

include/xrpl/protocol/HashPrefix.h

@@ -72,6 +72,9 @@ enum class HashPrefix : std::uint32_t {
 
     /** Batch */
     batch = detail::make_hash_prefix('B', 'C', 'H'),
+
+    /** Sponsor */
+    sponsor = detail::make_hash_prefix('S', 'P', 'N'),
 };
 
 template <class Hasher>

include/xrpl/protocol/Indexes.h

@@ -155,6 +155,10 @@ 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,
@@ -186,6 +188,10 @@ enum LedgerSpecificFlags {
 
     // ltVAULT
     lsfVaultPrivate = 0x00010000,
+
+    // ltSPONSORSHIP
+    lsfSponsorshipRequireSignForFee     = 0x00010000,
+    lsfSponsorshipRequireSignForReserve = 0x00020000,
 };
 
 //------------------------------------------------------------------------------

include/xrpl/protocol/Sponsor.h

@@ -0,0 +1,18 @@
+#include <xrpl/protocol/AccountID.h>
+#include <xrpl/protocol/HashPrefix.h>
+#include <xrpl/protocol/STVector256.h>
+#include <xrpl/protocol/Serializer.h>
+
+namespace ripple {
+
+inline void
+addSerializeSponsorData(
+    Serializer& msg,
+    AccountID const& sponsorID,
+    std::uint32_t const& flags)
+{
+    msg.addBitString(sponsorID);
+    msg.add32(flags);
+}
+
+}  // namespace ripple

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:
@@ -266,6 +273,14 @@ constexpr std::uint32_t tfIndependent                  = 0x00080000;
 constexpr std::uint32_t const tfBatchMask =
     ~(tfUniversal | tfAllOrNothing | tfOnlyOne | tfUntilFailure | tfIndependent) | tfInnerBatchTxn;
 
+// 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);
+
 // clang-format on
 
 }  // namespace ripple

include/xrpl/protocol/detail/features.macro

@@ -14,6 +14,7 @@
 // Add new amendments to the top of this list.
 // Keep it sorted in reverse chronological order.
 
+XRPL_FEATURE(Sponsor,                    Supported::no,  VoteBehavior::DefaultNo)
 XRPL_FEATURE(PermissionDelegationV1_1,   Supported::no,  VoteBehavior::DefaultNo)
 XRPL_FIX    (DirectoryLimit,             Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FIX    (IncludeKeyletFields,        Supported::yes, VoteBehavior::DefaultNo)

include/xrpl/protocol/detail/ledger_entries.macro

@@ -149,6 +149,9 @@ LEDGER_ENTRY(ltACCOUNT_ROOT, 0x0061, AccountRoot, account, ({
     {sfFirstNFTokenSequence, soeOPTIONAL},
     {sfAMMID,                soeOPTIONAL}, // pseudo-account designator
     {sfVaultID,              soeOPTIONAL}, // pseudo-account designator
+    {sfSponsoredOwnerCount,  soeOPTIONAL},
+    {sfSponsoringOwnerCount, soeOPTIONAL},
+    {sfSponsoringAccountCount,soeOPTIONAL},
 }))
 
 /** A ledger object which contains a list of object identifiers.
@@ -283,6 +286,8 @@ LEDGER_ENTRY(ltRIPPLE_STATE, 0x0072, RippleState, state, ({
     {sfHighNode,             soeOPTIONAL},
     {sfHighQualityIn,        soeOPTIONAL},
     {sfHighQualityOut,       soeOPTIONAL},
+    {sfHighSponsorAccount,   soeOPTIONAL},
+    {sfLowSponsorAccount,    soeOPTIONAL},
 }))
 
 /** The ledger object which lists the network's fee settings.
@@ -490,5 +495,18 @@ LEDGER_ENTRY(ltVAULT, 0x0084, Vault, vault, ({
     // no PermissionedDomainID ever (use MPTIssuance.sfDomainID)
 }))
 
+/** A ledger object representing a sponsorship.
+    \sa keylet::sponsor
+ */
+LEDGER_ENTRY(ltSPONSORSHIP, 0x0085, Sponsorship, sponsorship, ({
+    {sfOwner,                soeREQUIRED},
+    {sfSponsee,              soeREQUIRED},
+    {sfFeeAmount,            soeOPTIONAL},
+    {sfMaxFee,               soeOPTIONAL},
+    {sfReserveCount,         soeOPTIONAL},
+    {sfOwnerNode,            soeREQUIRED},
+    {sfSponseeNode,          soeREQUIRED},
+}))
+
 #undef EXPAND
 #undef LEDGER_ENTRY_DUPLICATE