Add support for XLS-81 Permissioned DEX (#5404)

Modified transactions:
- OfferCreate
- Payment

Modified RPCs:
- book_changes
- subscribe
- book_offers
- ripple_path_find
- path_find

Spec: https://github.com/XRPLF/XRPL-Standards/pull/281

include/xrpl/protocol/Book.h

@@ -21,6 +21,7 @@
 #define RIPPLE_PROTOCOL_BOOK_H_INCLUDED
 
 #include <xrpl/basics/CountedObject.h>
+#include <xrpl/basics/base_uint.h>
 #include <xrpl/protocol/Issue.h>
 
 #include <boost/utility/base_from_member.hpp>
@@ -36,12 +37,17 @@ class Book final : public CountedObject<Book>
 public:
     Issue in;
     Issue out;
+    std::optional<uint256> domain;
 
     Book()
     {
     }
 
-    Book(Issue const& in_, Issue const& out_) : in(in_), out(out_)
+    Book(
+        Issue const& in_,
+        Issue const& out_,
+        std::optional<uint256> const& domain_)
+        : in(in_), out(out_), domain(domain_)
     {
     }
 };
@@ -61,6 +67,8 @@ hash_append(Hasher& h, Book const& b)
 {
     using beast::hash_append;
     hash_append(h, b.in, b.out);
+    if (b.domain)
+        hash_append(h, *(b.domain));
 }
 
 Book
@@ -71,7 +79,8 @@ reversed(Book const& book);
 [[nodiscard]] inline constexpr bool
 operator==(Book const& lhs, Book const& rhs)
 {
-    return (lhs.in == rhs.in) && (lhs.out == rhs.out);
+    return (lhs.in == rhs.in) && (lhs.out == rhs.out) &&
+        (lhs.domain == rhs.domain);
 }
 /** @} */
 
@@ -82,7 +91,18 @@ operator<=>(Book const& lhs, Book const& rhs)
 {
     if (auto const c{lhs.in <=> rhs.in}; c != 0)
         return c;
-    return lhs.out <=> rhs.out;
+    if (auto const c{lhs.out <=> rhs.out}; c != 0)
+        return c;
+
+    // Manually compare optionals
+    if (lhs.domain && rhs.domain)
+        return *lhs.domain <=> *rhs.domain;  // Compare values if both exist
+    if (!lhs.domain && rhs.domain)
+        return std::weak_ordering::less;  // Empty is considered less
+    if (lhs.domain && !rhs.domain)
+        return std::weak_ordering::greater;  // Non-empty is greater
+
+    return std::weak_ordering::equivalent;  // Both are empty
 }
 /** @} */
 
@@ -126,9 +146,11 @@ template <>
 struct hash<ripple::Book>
 {
 private:
-    using hasher = std::hash<ripple::Issue>;
+    using issue_hasher = std::hash<ripple::Issue>;
+    using uint256_hasher = ripple::uint256::hasher;
 
-    hasher m_hasher;
+    issue_hasher m_issue_hasher;
+    uint256_hasher m_uint256_hasher;
 
 public:
     hash() = default;
@@ -139,8 +161,12 @@ public:
     value_type
     operator()(argument_type const& value) const
     {
-        value_type result(m_hasher(value.in));
-        boost::hash_combine(result, m_hasher(value.out));
+        value_type result(m_issue_hasher(value.in));
+        boost::hash_combine(result, m_issue_hasher(value.out));
+
+        if (value.domain)
+            boost::hash_combine(result, m_uint256_hasher(*value.domain));
+
         return result;
     }
 };

include/xrpl/protocol/ErrorCodes.h

@@ -154,7 +154,10 @@ enum error_code_i {
     // Simulate
     rpcTX_SIGNED = 96,
 
-    rpcLAST = rpcTX_SIGNED  // rpcLAST should always equal the last code.
+    // Pathfinding
+    rpcDOMAIN_MALFORMED = 97,
+
+    rpcLAST = rpcDOMAIN_MALFORMED  // rpcLAST should always equal the last code.
 };
 
 /** Codes returned in the `warnings` array of certain RPC commands.

include/xrpl/protocol/LedgerFormats.h

@@ -152,6 +152,7 @@ enum LedgerSpecificFlags {
     // ltOFFER
     lsfPassive = 0x00010000,
     lsfSell = 0x00020000,  // True, offer was placed as a sell.
+    lsfHybrid = 0x00040000,  // True, offer is hybrid.
 
     // ltRIPPLE_STATE
     lsfLowReserve = 0x00010000,  // True, if entry counts toward reserve.

include/xrpl/protocol/TxFlags.h

@@ -98,9 +98,9 @@ constexpr std::uint32_t tfPassive                          = 0x00010000;
 constexpr std::uint32_t tfImmediateOrCancel                = 0x00020000;
 constexpr std::uint32_t tfFillOrKill                       = 0x00040000;
 constexpr std::uint32_t tfSell                             = 0x00080000;
-
+constexpr std::uint32_t tfHybrid                           = 0x00100000;
 constexpr std::uint32_t tfOfferCreateMask =
-    ~(tfUniversal | tfPassive | tfImmediateOrCancel | tfFillOrKill | tfSell);
+    ~(tfUniversal | tfPassive | tfImmediateOrCancel | tfFillOrKill | tfSell | tfHybrid);
 
 // Payment flags:
 constexpr std::uint32_t tfNoRippleDirect                   = 0x00010000;

include/xrpl/protocol/UintTypes.h

@@ -63,6 +63,9 @@ using NodeID = base_uint<160, detail::NodeIDTag>;
  * and a 160-bit account */
 using MPTID = base_uint<192>;
 
+/** Domain is a 256-bit hash representing a specific domain. */
+using Domain = base_uint<256>;
+
 /** XRP currency. */
 Currency const&
 xrpCurrency();

include/xrpl/protocol/detail/features.macro

@@ -32,6 +32,7 @@
 // If you add an amendment here, then do not forget to increment `numFeatures`
 // in include/xrpl/protocol/Feature.h.
 
+XRPL_FEATURE(PermissionedDEX,            Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FEATURE(Batch,                      Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FEATURE(SingleAssetVault,           Supported::no, VoteBehavior::DefaultNo)
 XRPL_FEATURE(PermissionDelegation,       Supported::yes, VoteBehavior::DefaultNo)

include/xrpl/protocol/detail/ledger_entries.macro

@@ -188,6 +188,7 @@ LEDGER_ENTRY(ltDIR_NODE, 0x0064, DirectoryNode, directory, ({
     {sfNFTokenID,            soeOPTIONAL},
     {sfPreviousTxnID,        soeOPTIONAL},
     {sfPreviousTxnLgrSeq,    soeOPTIONAL},
+    {sfDomainID,             soeOPTIONAL}
 }))
 
 /** The ledger object which lists details about amendments on the network.
@@ -249,6 +250,8 @@ LEDGER_ENTRY(ltOFFER, 0x006f, Offer, offer, ({
     {sfPreviousTxnID,        soeREQUIRED},
     {sfPreviousTxnLgrSeq,    soeREQUIRED},
     {sfExpiration,           soeOPTIONAL},
+    {sfDomainID,             soeOPTIONAL},
+    {sfAdditionalBooks,      soeOPTIONAL},
 }))
 
 /** A ledger object which describes a deposit preauthorization.

include/xrpl/protocol/detail/sfields.macro

@@ -360,6 +360,7 @@ UNTYPED_SFIELD(sfPriceData,              OBJECT,    32)
 UNTYPED_SFIELD(sfCredential,             OBJECT,    33)
 UNTYPED_SFIELD(sfRawTransaction,         OBJECT,    34)
 UNTYPED_SFIELD(sfBatchSigner,            OBJECT,    35)
+UNTYPED_SFIELD(sfBook,                   OBJECT,    36)
 
 // array of objects (common)
 // ARRAY/1 is reserved for end of array
@@ -375,6 +376,7 @@ UNTYPED_SFIELD(sfMemos,                  ARRAY,      9)
 UNTYPED_SFIELD(sfNFTokens,               ARRAY,     10)
 UNTYPED_SFIELD(sfHooks,                  ARRAY,     11)
 UNTYPED_SFIELD(sfVoteSlots,              ARRAY,     12)
+UNTYPED_SFIELD(sfAdditionalBooks,        ARRAY,     13)
 
 // array of objects (uncommon)
 UNTYPED_SFIELD(sfMajorities,             ARRAY,     16)

include/xrpl/protocol/detail/transactions.macro

@@ -38,6 +38,7 @@ TRANSACTION(ttPAYMENT, 0, Payment, Delegation::delegatable, ({
     {sfDestinationTag, soeOPTIONAL},
     {sfDeliverMin, soeOPTIONAL, soeMPTSupported},
     {sfCredentialIDs, soeOPTIONAL},
+    {sfDomainID, soeOPTIONAL},
 }))
 
 /** This transaction type creates an escrow object. */
@@ -93,6 +94,7 @@ TRANSACTION(ttOFFER_CREATE, 7, OfferCreate, Delegation::delegatable, ({
     {sfTakerGets, soeREQUIRED},
     {sfExpiration, soeOPTIONAL},
     {sfOfferSequence, soeOPTIONAL},
+    {sfDomainID, soeOPTIONAL},
 }))
 
 /** This transaction type cancels existing offers to trade one asset for another. */