Add WithdrawalPolicy

include/xrpl/protocol/Protocol.h

@@ -118,6 +118,9 @@ std::uint64_t constexpr maxMPTokenAmount = 0x7FFF'FFFF'FFFF'FFFFull;
 /** The maximum length of MPTokenMetadata */
 std::size_t constexpr maxVaultDataLength = 256;
 
+/** Vault withdrawal policies */
+std::uint8_t constexpr vaultStrategyFirstComeFirstServe = 1;
+
 /** A ledger index. */
 using LedgerIndex = std::uint32_t;
 

include/xrpl/protocol/detail/ledger_entries.macro

@@ -480,9 +480,9 @@ LEDGER_ENTRY(ltVAULT, 0x0083, Vault, vault, ({
     {sfAssetMaximum,         soeDEFAULT},
     {sfLossUnrealized,       soeDEFAULT},
     {sfMPTokenIssuanceID,    soeREQUIRED}, // sfShare
+    {sfWithdrawalPolicy,     soeREQUIRED},
     // no ShareTotal ever (use MPTIssuance.sfOutstandingAmount)
-    // no PermissionedDomainID (use MPTIssuance.sfDomainID)
-    // no WithdrawalPolicy yet
+    // no PermissionedDomainID ever (use MPTIssuance.sfDomainID)
 }))
 
 #undef EXPAND

include/xrpl/protocol/detail/sfields.macro

@@ -42,6 +42,7 @@ TYPED_SFIELD(sfTickSize,                 UINT8,     16)
 TYPED_SFIELD(sfUNLModifyDisabling,       UINT8,     17)
 TYPED_SFIELD(sfHookResult,               UINT8,     18)
 TYPED_SFIELD(sfWasLockingChainSend,      UINT8,     19)
+TYPED_SFIELD(sfWithdrawalPolicy,         UINT8,     20)
 
 // 16-bit integers (common)
 TYPED_SFIELD(sfLedgerEntryType,          UINT16,     1, SField::sMD_Never)

include/xrpl/protocol/detail/transactions.macro

@@ -471,7 +471,7 @@ TRANSACTION(ttVAULT_CREATE, 64, VaultCreate, ({
     {sfAssetMaximum, soeOPTIONAL},
     {sfMPTokenMetadata, soeOPTIONAL},
     {sfDomainID, soeOPTIONAL}, // PermissionedDomainID
-    // no WithdrawalPolicy yet
+    {sfWithdrawalPolicy, soeOPTIONAL},
     {sfData, soeOPTIONAL},
 }))
 
@@ -480,7 +480,6 @@ TRANSACTION(ttVAULT_SET, 65, VaultSet, ({
     {sfVaultID, soeREQUIRED},
     {sfAssetMaximum, soeOPTIONAL},
     {sfDomainID, soeOPTIONAL}, // PermissionedDomainID
-    // no WithdrawalPolicy yet
     {sfData, soeOPTIONAL},
 }))
 

src/test/app/Vault_test.cpp

@@ -287,6 +287,32 @@ class Vault_test : public beast::unit_test::suite
             env(tx);
         });
 
+        testCase([this](
+                     Env& env,
+                     Account const& issuer,
+                     Account const& owner,
+                     Account const& depositor,
+                     Asset const& asset,
+                     Vault& vault) {
+            auto [tx, keylet] = vault.create({.owner = owner, .asset = asset});
+            tx[sfWithdrawalPolicy] = 1;
+            testcase("explicitly select withdrawal policy");
+            env(tx);
+        });
+
+        testCase([this](
+                     Env& env,
+                     Account const& issuer,
+                     Account const& owner,
+                     Account const& depositor,
+                     Asset const& asset,
+                     Vault& vault) {
+            auto [tx, keylet] = vault.create({.owner = owner, .asset = asset});
+            tx[sfWithdrawalPolicy] = 0;
+            testcase("invalid withdrawal policy");
+            env(tx, ter(temMALFORMED));
+        });
+
         testCase([this](
                      Env& env,
                      Account const& issuer,

src/xrpld/app/tx/detail/VaultCreate.cpp

@@ -23,6 +23,7 @@
 #include <xrpl/protocol/Feature.h>
 #include <xrpl/protocol/Indexes.h>
 #include <xrpl/protocol/MPTIssue.h>
+#include <xrpl/protocol/Protocol.h>
 #include <xrpl/protocol/STNumber.h>
 #include <xrpl/protocol/TER.h>
 #include <xrpl/protocol/TxFlags.h>
@@ -51,6 +52,13 @@ VaultCreate::preflight(PreflightContext const& ctx)
             return temMALFORMED;
     }
 
+    if (auto const data = ctx.tx[~sfWithdrawalPolicy])
+    {
+        // Enforce valid withdrawal policy
+        if (*data != vaultStrategyFirstComeFirstServe)
+            return temMALFORMED;
+    }
+
     if (auto const domain = ctx.tx[~sfDomainID])
     {
         if (*domain == beast::zero)
@@ -176,6 +184,11 @@ VaultCreate::doApply()
     vault->at(sfMPTokenIssuanceID) = share;
     if (auto value = tx[~sfData])
         vault->at(sfData) = *value;
+    // Required field, default to vaultStrategyFirstComeFirstServe
+    if (auto value = tx[~sfWithdrawalPolicy])
+        vault->at(sfWithdrawalPolicy) = *value;
+    else
+        vault->at(sfWithdrawalPolicy) = vaultStrategyFirstComeFirstServe;
     // No `LossUnrealized`.
     view().insert(vault);
 

src/xrpld/app/tx/detail/VaultWithdraw.cpp

@@ -51,6 +51,10 @@ VaultWithdraw::preclaim(PreclaimContext const& ctx)
     if (!vault)
         return tecOBJECT_NOT_FOUND;
 
+    // Enforce valid withdrawal policy
+    if (vault->at(sfWithdrawalPolicy) != vaultStrategyFirstComeFirstServe)
+        return tefINTERNAL;
+
     auto const assets = ctx.tx[sfAmount];
     auto const asset = vault->at(sfAsset);
     auto const share = vault->at(sfMPTokenIssuanceID);

src/xrpld/ledger/detail/View.cpp

@@ -2531,7 +2531,6 @@ assetsToSharesWithdraw(
         return shares;
     Number shareTotal = getShareTotal(view, vault);
     shares = shareTotal * (assets / assetTotal);
-    // TODO: Limit by withdrawal policy?
     return shares;
 }
 
@@ -2549,7 +2548,6 @@ sharesToAssetsWithdraw(
         return assets;
     Number shareTotal = getShareTotal(view, vault);
     assets = assetTotal * (shares / shareTotal);
-    // TODO: Limit by withdrawal policy?
     return assets;
 }