feat: Move VaultWithdraw invariants from ValidVault to VaultWithdraw

include/xrpl/tx/invariants/VaultInvariantData.h

@@ -2,22 +2,26 @@
 
 #include <xrpl/basics/Number.h>
 #include <xrpl/basics/base_uint.h>
+#include <xrpl/ledger/ReadView.h>
 #include <xrpl/protocol/AccountID.h>
 #include <xrpl/protocol/Asset.h>
 #include <xrpl/protocol/MPTIssue.h>
 #include <xrpl/protocol/STLedgerEntry.h>
+#include <xrpl/protocol/STTx.h>
+#include <xrpl/protocol/XRPAmount.h>
 
 #include <optional>
+#include <unordered_map>
 #include <vector>
 
 namespace xrpl {
 
 /**
- * @brief Collects vault and share-issuance snapshots from ledger entry visits.
+ * @brief Collects vault and share-issuance snapshots from ledger entry visits,
+ * including full balance-delta tracking for per-transaction invariant checks.
  *
- * Used by per-transaction invariant checks (e.g. VaultCreate) that need
- * vault and MPTokenIssuance state without the full balance-delta tracking
- * that ValidVault maintains.
+ * Used by per-transaction invariant checks (e.g. VaultCreate, VaultWithdraw)
+ * that need vault and MPTokenIssuance state with balance-delta tracking.
  */
 class VaultInvariantData
 {
@@ -48,6 +52,16 @@ public:
         make(SLE const&);
     };
 
+    struct DeltaInfo
+    {
+        Number delta = kNumZero;
+        std::optional<int> scale;
+
+        // Compute the delta between two Numbers, taking the coarsest scale
+        [[nodiscard]] static DeltaInfo
+        makeDelta(Number const& before, Number const& after, Asset const& asset);
+    };
+
     void
     visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after);
 
@@ -67,10 +81,93 @@ public:
     [[nodiscard]] std::optional<Shares>
     findShares(uint192 const& mptID) const;
 
+    /**
+     * @brief Find a deleted (before-only) MPTokenIssuance whose mptID matches.
+     *
+     * Returns the Shares snapshot captured in beforeMPTs_ for the given mptID,
+     * or std::nullopt if none was deleted in this transaction.
+     */
+    [[nodiscard]] std::optional<Shares>
+    findDeletedShares(uint192 const& mptID) const;
+
+    /** All MPTokenIssuance snapshots captured before modification or deletion. */
+    [[nodiscard]] std::vector<Shares> const&
+    beforeMPTIssuances() const
+    {
+        return beforeMPTs_;
+    }
+
+    /**
+     * @brief Return the vault-asset balance-change delta for an account.
+     *
+     * Looks up the ledger-entry delta recorded during visitEntry for the
+     * account entry (XRP), trust line (IOU), or MPToken (MPT) that corresponds
+     * to the vault asset held by id.
+     *
+     * @param id Account whose asset delta is requested.
+     * @returns The delta, or std::nullopt if the entry was not touched.
+     */
+    [[nodiscard]] std::optional<DeltaInfo>
+    deltaAssets(AccountID const& id) const;
+
+    /**
+     * @brief Return the vault-asset delta for the transaction's sending
+     *        account, adjusted for the fee.
+     *
+     * Calls deltaAssets for tx[sfAccount] and, for non-delegated XRP
+     * transactions, adds the consumed fee back so the invariant sees the net
+     * asset movement rather than the fee-reduced balance change.
+     *
+     * @param tx  The transaction being applied.
+     * @param fee Fee charged by this transaction.
+     * @returns The fee-adjusted delta, or std::nullopt if the net delta is
+     *          zero or the account entry was not touched.
+     */
+    [[nodiscard]] std::optional<DeltaInfo>
+    deltaAssetsTxAccount(STTx const& tx, XRPAmount fee) const;
+
+    /**
+     * @brief Return the vault-share balance-change delta for an account.
+     *
+     * For the vault's pseudo-account the MPTokenIssuance outstanding-amount
+     * delta is returned; for all other accounts the MPToken delta is returned.
+     *
+     * @param id Account whose share delta is requested.
+     * @returns The delta, or std::nullopt if the entry was not touched.
+     */
+    [[nodiscard]] std::optional<DeltaInfo>
+    deltaShares(AccountID const& id) const;
+
+    /**
+     * @brief Compute the coarsest scale required to represent all numbers.
+     */
+    [[nodiscard]] static std::int32_t
+    computeCoarsestScale(std::vector<DeltaInfo> const& numbers);
+
+    /**
+     * @brief Compute the minimum STAmount scale for rounding invariant
+     *        calculations.
+     *
+     * Post-amendment (fixCleanup3_2_0) this is simply the posterior
+     * assetsTotal scale.  Pre-amendment it is the coarsest scale across
+     * vaultDelta and both asset-field deltas.
+     *
+     * @param vaultDelta Delta of the vault's asset balance for this transaction.
+     * @param rules      Active ledger rules (used to check the amendment).
+     * @returns The minimum scale to apply when rounding vault-related amounts.
+     */
+    [[nodiscard]] std::int32_t
+    computeVaultMinScale(DeltaInfo const& vaultDelta, Rules const& rules) const;
+
 private:
     std::vector<Vault> afterVault_;
     std::vector<Vault> beforeVault_;
     std::vector<Shares> afterMPTs_;
+    std::vector<Shares> beforeMPTs_;
+    std::unordered_map<uint256, DeltaInfo> deltas_;
+
+    [[nodiscard]] std::optional<DeltaInfo>
+    lookupDelta(uint256 const& key) const;
 };
 
 }  // namespace xrpl

include/xrpl/tx/transactors/vault/VaultWithdraw.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <xrpl/tx/Transactor.h>
+#include <xrpl/tx/invariants/VaultInvariantData.h>
 
 namespace xrpl {
 
@@ -32,6 +33,9 @@ public:
         XRPAmount fee,
         ReadView const& view,
         beast::Journal const& j) override;
+
+private:
+    VaultInvariantData data_;
 };
 
 }  // namespace xrpl