Move Trustline to xrpl/ledger

Signed-off-by: JCW <a1q123456@users.noreply.github.com>

include/xrpl/ledger/TrustLine.h

@@ -0,0 +1,224 @@
+/**
+ * @file TrustLine.h
+ * @brief Wrapper for trust line (RippleState) ledger entries.
+ */
+
+#pragma once
+
+#include <xrpl/basics/CountedObject.h>
+#include <xrpl/ledger/ReadView.h>
+#include <xrpl/protocol/Rate.h>
+#include <xrpl/protocol/STLedgerEntry.h>
+#include <xrpl/protocol_autogen/ledger_entries/RippleState.h>
+
+#include <cstdint>
+#include <memory>
+#include <optional>
+#include <vector>
+
+namespace xrpl {
+
+/**
+ * @brief Describes how an account was found in a path.
+ *
+ * "Outgoing" is defined as the source account, or an account found via a
+ * trust line that has rippling enabled on the account's side.
+ *
+ * "Incoming" is defined as an account found via a trust line that has rippling
+ * disabled on the account's side. Any trust lines for an incoming account that
+ * have rippling disabled are unusable in paths.
+ */
+enum class LineDirection : bool { incoming = false, outgoing = true };
+
+/**
+ * @brief Wraps a trust line SLE for convenience.
+ *
+ * The complication of trust lines is that there is a "low" account and a
+ * "high" account. This wraps the SLE and expresses its data from the
+ * perspective of a chosen account on the line.
+ *
+ * This class uses a thin wrapper around the SLE to minimise memory usage.
+ * The SLE must remain valid for the lifetime of this object.
+ */
+class TrustLine final : public CountedObject<TrustLine>
+{
+public:
+    TrustLine() = delete;
+
+    /**
+     * @brief Construct a TrustLine from a RippleState ledger entry.
+     * @param rippleState The RippleState ledger entry.
+     * @param viewAccount The account from whose perspective to view the line.
+     */
+    TrustLine(ledger_entries::RippleState const& rippleState, AccountID const& viewAccount);
+
+    /**
+     * @brief Create a TrustLine from an SLE if it is a valid RippleState.
+     * @param accountID The account from whose perspective to view the line.
+     * @param sle The shared ledger entry.
+     * @return The TrustLine, or nullopt if the SLE is not a RippleState.
+     */
+    static std::optional<TrustLine>
+    makeItem(AccountID const& accountID, std::shared_ptr<SLE const> const& sle);
+
+    /**
+     * @brief Get all trust lines for an account.
+     * @param accountID The account to get trust lines for.
+     * @param view The ledger view to read from.
+     * @param direction Filter by line direction (default: outgoing).
+     * @return A vector of TrustLine objects.
+     */
+    static std::vector<TrustLine>
+    getItems(
+        AccountID const& accountID,
+        ReadView const& view,
+        LineDirection direction = LineDirection::outgoing);
+
+    /**
+     * @brief Returns the state map key for the ledger entry.
+     * @return The key (hash) of the RippleState entry.
+     */
+    uint256 const&
+    key() const;
+
+    /**
+     * @brief Get our account ID.
+     * @return The account ID from whose perspective this line is viewed.
+     */
+    AccountID const&
+    getAccountID() const;
+
+    /**
+     * @brief Get the peer's account ID.
+     * @return The account ID of the other party on this trust line.
+     */
+    AccountID const&
+    getAccountIDPeer() const;
+
+    /**
+     * @brief Check if we have authorised the peer.
+     * @return True if we have provided authorisation to the peer.
+     */
+    bool
+    getAuth() const;
+
+    /**
+     * @brief Check if the peer has authorised us.
+     * @return True if the peer has provided authorisation to us.
+     */
+    bool
+    getAuthPeer() const;
+
+    /**
+     * @brief Check if we have the NoRipple flag set.
+     * @return True if NoRipple is set on our side.
+     */
+    bool
+    getNoRipple() const;
+
+    /**
+     * @brief Check if the peer has the NoRipple flag set.
+     * @return True if NoRipple is set on the peer's side.
+     */
+    bool
+    getNoRipplePeer() const;
+
+    /**
+     * @brief Get our line direction based on NoRipple flag.
+     * @return Incoming if NoRipple is set, outgoing otherwise.
+     */
+    LineDirection
+    getDirection() const
+    {
+        return getNoRipple() ? LineDirection::incoming : LineDirection::outgoing;
+    }
+
+    /**
+     * @brief Get the peer's line direction based on their NoRipple flag.
+     * @return Incoming if peer's NoRipple is set, outgoing otherwise.
+     */
+    LineDirection
+    getDirectionPeer() const
+    {
+        return getNoRipplePeer() ? LineDirection::incoming : LineDirection::outgoing;
+    }
+
+    /**
+     * @brief Check if we have frozen the peer.
+     * @return True if we have set the freeze flag on the peer.
+     */
+    bool
+    getFreeze() const;
+
+    /**
+     * @brief Check if we have deep frozen the peer.
+     * @return True if we have set the deep freeze flag on the peer.
+     */
+    bool
+    getDeepFreeze() const;
+
+    /**
+     * @brief Check if the peer has frozen us.
+     * @return True if the peer has set the freeze flag on us.
+     */
+    bool
+    getFreezePeer() const;
+
+    /**
+     * @brief Check if the peer has deep frozen us.
+     * @return True if the peer has set the deep freeze flag on us.
+     */
+    bool
+    getDeepFreezePeer() const;
+
+    /**
+     * @brief Get the balance on this trust line.
+     * @return The balance from our perspective (positive = we hold IOUs).
+     */
+    STAmount
+    getBalance() const;
+
+    /**
+     * @brief Get our trust limit.
+     * @return The maximum amount we are willing to hold.
+     */
+    STAmount
+    getLimit() const;
+
+    /**
+     * @brief Get the peer's trust limit.
+     * @return The maximum amount the peer is willing to hold.
+     */
+    STAmount
+    getLimitPeer() const;
+
+    /**
+     * @brief Get the quality in rate.
+     * @return The rate applied to incoming payments.
+     */
+    Rate
+    getQualityIn() const;
+
+    /**
+     * @brief Get the quality out rate.
+     * @return The rate applied to outgoing payments.
+     */
+    Rate
+    getQualityOut() const;
+
+    /**
+     * @brief Get a JSON representation of this trust line.
+     * @param level Detail level for the JSON output.
+     * @return JSON value representing this trust line.
+     */
+    Json::Value
+    getJson(int level);
+
+private:
+    TrustLine(std::shared_ptr<SLE const> sle, AccountID const& viewAccount);
+
+    ledger_entries::RippleState rippleState_; /**< The underlying RippleState entry. */
+    bool viewLowest_;                         /**< True if viewAccount is the low account. */
+};
+
+}  // namespace xrpl