XLS-78d: Subscriptions

include/xrpl/protocol/Feature.h

@@ -80,7 +80,7 @@ namespace detail {
 // Feature.cpp. Because it's only used to reserve storage, and determine how
 // large to make the FeatureBitset, it MAY be larger. It MUST NOT be less than
 // the actual number of amendments. A LogicError on startup will verify this.
-static constexpr std::size_t numFeatures = 79;
+static constexpr std::size_t numFeatures = 80;
 
 /** Amendments that this server supports and the default voting behavior.
    Whether they are enabled depends on the Rules defined in the validated
@@ -372,6 +372,7 @@ extern uint256 const fixEnforceNFTokenTrustline;
 extern uint256 const fixInnerObjTemplate2;
 extern uint256 const featureInvariantsV1_1;
 extern uint256 const fixNFTokenPageLinks;
+extern uint256 const featureSubscription;
 
 }  // namespace ripple
 

include/xrpl/protocol/Indexes.h

@@ -287,6 +287,18 @@ did(AccountID const& account) noexcept;
 Keylet
 oracle(AccountID const& account, std::uint32_t const& documentID) noexcept;
 
+Keylet
+subscription(
+    AccountID const& account,
+    AccountID const& dest,
+    std::uint32_t const& seq) noexcept;
+
+inline Keylet
+subscription(uint256 const& key) noexcept
+{
+    return {ltSUBSCRIPTION, key};
+}
+
 }  // namespace keylet
 
 // Everything below is deprecated and should be removed in favor of keylets:

include/xrpl/protocol/LedgerFormats.h

@@ -197,6 +197,11 @@ enum LedgerEntryType : std::uint16_t
      */
     ltORACLE = 0x0080,
 
+    /** A ledger object which tracks Subscription
+        \sa keylet::subscription
+     */
+    ltSUBSCRIPTION = 0x0055,
+
     //---------------------------------------------------------------------------
     /** A special type, matching any ledger entry type.
 

include/xrpl/protocol/SField.h

@@ -442,6 +442,9 @@ extern SF_UINT32 const sfEmitGeneration;
 extern SF_UINT32 const sfVoteWeight;
 extern SF_UINT32 const sfFirstNFTokenSequence;
 extern SF_UINT32 const sfOracleDocumentID;
+extern SF_UINT32 const sfFrequency;
+extern SF_UINT32 const sfStartTime;
+extern SF_UINT32 const sfNextPaymentTime;
 
 // 64-bit integers (common)
 extern SF_UINT64 const sfIndexNext;
@@ -511,6 +514,7 @@ extern SF_UINT256 const sfHookStateKey;
 extern SF_UINT256 const sfHookHash;
 extern SF_UINT256 const sfHookNamespace;
 extern SF_UINT256 const sfHookSetTxnID;
+extern SF_UINT256 const sfSubscriptionID;
 
 // currency amount (common)
 extern SF_AMOUNT const sfAmount;

include/xrpl/protocol/TxFormats.h

@@ -199,6 +199,15 @@ enum TxType : std::uint16_t
     /** This transaction type fixes a problem in the ledger state */
     ttLEDGER_STATE_FIX = 53,
 
+    /** This transaction type creates an Subscription instance */
+    ttSUBSCRIPTION_SET = 54,
+
+    /** This transaction type cancels an Subscription instance */
+    ttSUBSCRIPTION_CANCEL = 55,
+
+    /** This transaction type claims an Subscription instance */
+    ttSUBSCRIPTION_CLAIM = 56,
+
 
     /** This system-generated transaction type is used to update the status of the various amendments.
 

include/xrpl/protocol/jss.h

@@ -89,6 +89,7 @@ JSS(EscrowFinish);         // transaction type.
 JSS(Fee);                  // in/out: TransactionSign; field.
 JSS(FeeSettings);          // ledger type.
 JSS(Flags);                // in/out: TransactionSign; field.
+JSS(Frequency);            // field.
 JSS(Invalid);              //
 JSS(LastLedgerSequence);   // in: TransactionSign; field
 JSS(LastUpdateTime);       // field.
@@ -140,6 +141,11 @@ JSS(SetRegularKey);                      // transaction type.
 JSS(SignerList);                         // ledger type.
 JSS(SignerListSet);                      // transaction type.
 JSS(SigningPubKey);                      // field.
+JSS(Subscription);                       // ledger type.
+JSS(SubscriptionCancel);                 // transaction type.
+JSS(SubscriptionClaim);                  // transaction type.
+JSS(SubscriptionID);                     // field.
+JSS(SubscriptionSet);                    // transaction type.
 JSS(TakerGets);                          // field.
 JSS(TakerPays);                          // field.
 JSS(Ticket);                             // ledger type.
@@ -651,6 +657,7 @@ JSS(streams);               // in: Subscribe, Unsubscribe
 JSS(strict);                // in: AccountCurrencies, AccountInfo
 JSS(sub_index);             // in: LedgerEntry
 JSS(subcommand);            // in: PathFind
+JSS(subscription);          // in: LedgerEntry
 JSS(success);               // rpc
 JSS(supported);             // out: AmendmentTableImpl
 JSS(sync_mode);             // in: Submit

src/libxrpl/protocol/Feature.cpp

@@ -498,6 +498,8 @@ REGISTER_FIX    (fixReducedOffersV2,            Supported::yes, VoteBehavior::De
 REGISTER_FIX    (fixEnforceNFTokenTrustline,    Supported::yes, VoteBehavior::DefaultNo);
 REGISTER_FIX    (fixInnerObjTemplate2,          Supported::yes, VoteBehavior::DefaultNo);
 REGISTER_FIX    (fixNFTokenPageLinks,           Supported::yes, VoteBehavior::DefaultNo);
+REGISTER_FEATURE(Subscription,                  Supported::yes, VoteBehavior::DefaultNo);
+
 // InvariantsV1_1 will be changes to Supported::yes when all the
 // invariants expected to be included under it are complete.
 REGISTER_FEATURE(InvariantsV1_1,                Supported::no, VoteBehavior::DefaultNo);

src/libxrpl/protocol/Indexes.cpp

@@ -73,6 +73,7 @@ enum class LedgerNameSpace : std::uint16_t {
     XCHAIN_CREATE_ACCOUNT_CLAIM_ID = 'K',
     DID = 'I',
     ORACLE = 'R',
+    SUBSCRIPTION = 'U',
 
     // No longer used or supported. Left here to reserve the space
     // to avoid accidental reuse.
@@ -451,6 +452,17 @@ oracle(AccountID const& account, std::uint32_t const& documentID) noexcept
     return {ltORACLE, indexHash(LedgerNameSpace::ORACLE, account, documentID)};
 }
 
+Keylet
+subscription(
+    AccountID const& account,
+    AccountID const& dest,
+    std::uint32_t const& seq) noexcept
+{
+    return {
+        ltSUBSCRIPTION,
+        indexHash(LedgerNameSpace::SUBSCRIPTION, account, dest, seq)};
+}
+
 }  // namespace keylet
 
 }  // namespace ripple

src/libxrpl/protocol/LedgerFormats.cpp

@@ -364,6 +364,23 @@ LedgerFormats::LedgerFormats()
             {sfPreviousTxnLgrSeq,   soeREQUIRED}
         },
         commonFields);
+
+    add(jss::Subscription,
+        ltSUBSCRIPTION,
+        {
+            {sfAccount,             soeREQUIRED},
+            {sfDestination,         soeREQUIRED},
+            {sfDestinationTag,      soeOPTIONAL},
+            {sfAmount,              soeREQUIRED},
+            {sfFrequency,           soeREQUIRED},
+            {sfNextPaymentTime,     soeREQUIRED},
+            {sfExpiration,          soeOPTIONAL},
+            {sfOwnerNode,           soeREQUIRED},
+            {sfPreviousTxnID,       soeREQUIRED},
+            {sfPreviousTxnLgrSeq,   soeREQUIRED},
+            {sfDestinationNode,     soeREQUIRED},
+        },
+        commonFields);
 
     // clang-format on
 }

src/libxrpl/protocol/SField.cpp

@@ -168,6 +168,9 @@ CONSTRUCT_TYPED_SFIELD(sfEmitGeneration,        "EmitGeneration",       UINT32,
 CONSTRUCT_TYPED_SFIELD(sfVoteWeight,            "VoteWeight",           UINT32,    48);
 CONSTRUCT_TYPED_SFIELD(sfFirstNFTokenSequence,  "FirstNFTokenSequence", UINT32,    50);
 CONSTRUCT_TYPED_SFIELD(sfOracleDocumentID,      "OracleDocumentID",     UINT32,    51);
+CONSTRUCT_TYPED_SFIELD(sfFrequency,             "Frequency",            UINT32,    52);
+CONSTRUCT_TYPED_SFIELD(sfStartTime,             "StartTime",            UINT32,    53);
+CONSTRUCT_TYPED_SFIELD(sfNextPaymentTime,       "NextPaymentTime",      UINT32,    54);
 
 // 64-bit integers (common)
 CONSTRUCT_TYPED_SFIELD(sfIndexNext,             "IndexNext",            UINT64,     1);
@@ -238,6 +241,7 @@ CONSTRUCT_TYPED_SFIELD(sfHookStateKey,          "HookStateKey",         UINT256,
 CONSTRUCT_TYPED_SFIELD(sfHookHash,              "HookHash",             UINT256,   31);
 CONSTRUCT_TYPED_SFIELD(sfHookNamespace,         "HookNamespace",        UINT256,   32);
 CONSTRUCT_TYPED_SFIELD(sfHookSetTxnID,          "HookSetTxnID",         UINT256,   33);
+CONSTRUCT_TYPED_SFIELD(sfSubscriptionID,        "SubscriptionID",       UINT256,   34);
 
 // currency amount (common)
 CONSTRUCT_TYPED_SFIELD(sfAmount,                "Amount",               AMOUNT,     1);

src/libxrpl/protocol/TxFormats.cpp

@@ -513,6 +513,34 @@ TxFormats::TxFormats()
             {sfOwner, soeOPTIONAL},
         },
         commonFields);
+
+    add(jss::SubscriptionSet,
+        ttSUBSCRIPTION_SET,
+        {
+            {sfDestination, soeOPTIONAL},
+            {sfDestinationTag, soeOPTIONAL},
+            {sfAmount, soeREQUIRED},
+            {sfFrequency, soeOPTIONAL},
+            {sfStartTime, soeOPTIONAL},
+            {sfExpiration, soeOPTIONAL},
+            {sfSubscriptionID, soeOPTIONAL},
+        },
+        commonFields);
+
+    add(jss::SubscriptionCancel,
+        ttSUBSCRIPTION_CANCEL,
+        {
+            {sfSubscriptionID, soeREQUIRED},
+        },
+        commonFields);
+
+    add(jss::SubscriptionClaim,
+        ttSUBSCRIPTION_CLAIM,
+        {
+            {sfSubscriptionID, soeREQUIRED},
+            {sfAmount, soeREQUIRED},
+        },
+        commonFields);
 }
 
 TxFormats const&