Implement amm_info handler (#1060)

Fixes #283

CMakeLists.txt

@@ -116,6 +116,7 @@ target_sources (clio PRIVATE
   ## RPC
   src/rpc/Errors.cpp
   src/rpc/Factories.cpp
+  src/rpc/AMMHelpers.cpp
   src/rpc/RPCHelpers.cpp
   src/rpc/Counters.cpp
   src/rpc/WorkQueue.cpp
@@ -133,6 +134,7 @@ target_sources (clio PRIVATE
   src/rpc/handlers/AccountObjects.cpp
   src/rpc/handlers/AccountOffers.cpp
   src/rpc/handlers/AccountTx.cpp
+  src/rpc/handlers/AMMInfo.cpp
   src/rpc/handlers/BookChanges.cpp
   src/rpc/handlers/BookOffers.cpp
   src/rpc/handlers/DepositAuthorized.cpp
@@ -248,6 +250,7 @@ if (tests)
     unittests/rpc/handlers/BookChangesTests.cpp
     unittests/rpc/handlers/LedgerTests.cpp
     unittests/rpc/handlers/VersionHandlerTests.cpp
+    unittests/rpc/handlers/AMMInfoTests.cpp
     # Backend
     unittests/data/BackendFactoryTests.cpp
     unittests/data/BackendCountersTests.cpp

src/data/BackendInterface.cpp

@@ -129,6 +129,7 @@ BackendInterface::fetchLedgerObjects(
 
     return results;
 }
+
 // Fetches the successor to key/index
 std::optional<ripple::uint256>
 BackendInterface::fetchSuccessorKey(

src/rpc/AMMHelpers.cpp

@@ -0,0 +1,82 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2024, the clio developers.
+
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include "rpc/AMMHelpers.h"
+
+#include "data/BackendInterface.h"
+#include "util/log/Logger.h"
+
+#include <ripple/protocol/AMMCore.h>
+
+namespace rpc {
+
+std::pair<ripple::STAmount, ripple::STAmount>
+getAmmPoolHolds(
+    BackendInterface const& backend,
+    std::uint32_t sequence,
+    ripple::AccountID const& ammAccountID,
+    ripple::Issue const& issue1,
+    ripple::Issue const& issue2,
+    bool freezeHandling,
+    boost::asio::yield_context yield
+)
+{
+    auto const assetInBalance =
+        accountHolds(backend, sequence, ammAccountID, issue1.currency, issue1.account, freezeHandling, yield);
+    auto const assetOutBalance =
+        accountHolds(backend, sequence, ammAccountID, issue2.currency, issue2.account, freezeHandling, yield);
+    return std::make_pair(assetInBalance, assetOutBalance);
+}
+
+ripple::STAmount
+getAmmLpHolds(
+    BackendInterface const& backend,
+    std::uint32_t sequence,
+    ripple::Currency const& cur1,
+    ripple::Currency const& cur2,
+    ripple::AccountID const& ammAccount,
+    ripple::AccountID const& lpAccount,
+    boost::asio::yield_context yield
+)
+{
+    auto const lptCurrency = ammLPTCurrency(cur1, cur2);
+    return accountHolds(backend, sequence, lpAccount, lptCurrency, ammAccount, true, yield);
+}
+
+ripple::STAmount
+getAmmLpHolds(
+    BackendInterface const& backend,
+    std::uint32_t sequence,
+    ripple::SLE const& ammSle,
+    ripple::AccountID const& lpAccount,
+    boost::asio::yield_context yield
+)
+{
+    return getAmmLpHolds(
+        backend,
+        sequence,
+        ammSle[ripple::sfAsset].currency,
+        ammSle[ripple::sfAsset2].currency,
+        ammSle[ripple::sfAccount],
+        lpAccount,
+        yield
+    );
+}
+
+}  // namespace rpc

src/rpc/AMMHelpers.h

@@ -0,0 +1,67 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2024, the clio developers.
+
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#pragma once
+
+#include "data/BackendInterface.h"
+#include "rpc/RPCHelpers.h"
+
+namespace rpc {
+
+/**
+ * @brief getAmmPoolHolds returns the balances of the amm asset pair.
+ */
+std::pair<ripple::STAmount, ripple::STAmount>
+getAmmPoolHolds(
+    BackendInterface const& backend,
+    std::uint32_t sequence,
+    ripple::AccountID const& ammAccountID,
+    ripple::Issue const& issue1,
+    ripple::Issue const& issue2,
+    bool freezeHandling,
+    boost::asio::yield_context yield
+);
+
+/**
+ * @brief getAmmLpHolds returns the lp token balance.
+ */
+ripple::STAmount
+getAmmLpHolds(
+    BackendInterface const& backend,
+    std::uint32_t sequence,
+    ripple::Currency const& cur1,
+    ripple::Currency const& cur2,
+    ripple::AccountID const& ammAccount,
+    ripple::AccountID const& lpAccount,
+    boost::asio::yield_context yield
+);
+
+/**
+ * @brief getAmmLpHolds returns the lp token balance.
+ */
+ripple::STAmount
+getAmmLpHolds(
+    BackendInterface const& backend,
+    std::uint32_t sequence,
+    ripple::SLE const& ammSle,
+    ripple::AccountID const& lpAccount,
+    boost::asio::yield_context yield
+);
+
+}  // namespace rpc

src/rpc/RPCHelpers.cpp

@@ -988,7 +988,7 @@ xrpLiquid(
     boost::asio::yield_context yield
 )
 {
-    auto key = ripple::keylet::account(id).key;
+    auto const key = ripple::keylet::account(id).key;
     auto blob = backend.fetchLedgerObject(key, sequence, yield);
 
     if (!blob)
@@ -999,13 +999,18 @@ xrpLiquid(
 
     std::uint32_t const ownerCount = sle.getFieldU32(ripple::sfOwnerCount);
 
-    auto const reserve = backend.fetchFees(sequence, yield)->accountReserve(ownerCount);
+    auto balance = sle.getFieldAmount(ripple::sfBalance);
 
-    auto const balance = sle.getFieldAmount(ripple::sfBalance);
-
-    ripple::STAmount amount = balance - reserve;
-    if (balance < reserve)
-        amount.clear();
+    ripple::STAmount const amount = [&]() {
+        // AMM doesn't require the reserves
+        if ((sle.getFlags() & ripple::lsfAMMNode) != 0u)
+            return balance;
+        auto const reserve = backend.fetchFees(sequence, yield)->accountReserve(ownerCount);
+        ripple::STAmount amount = balance - reserve;
+        if (balance < reserve)
+            amount.clear();
+        return amount;
+    }();
 
     return amount.xrp();
 }
@@ -1038,11 +1043,10 @@ accountHolds(
 )
 {
     ripple::STAmount amount;
-    if (ripple::isXRP(currency)) {
+    if (ripple::isXRP(currency))
         return {xrpLiquid(backend, sequence, account, yield)};
-    }
-    auto key = ripple::keylet::line(account, issuer, currency).key;
 
+    auto const key = ripple::keylet::line(account, issuer, currency).key;
     auto const blob = backend.fetchLedgerObject(key, sequence, yield);
 
     if (!blob) {

src/rpc/common/Validators.cpp

@@ -212,4 +212,24 @@ CustomValidator SubscribeAccountsValidator =
         return MaybeError{};
     }};
 
+CustomValidator AMMAssetValidator =
+    CustomValidator{[](boost::json::value const& value, std::string_view key) -> MaybeError {
+        if (not value.is_object())
+            return Error{Status{RippledError::rpcINVALID_PARAMS, std::string(key) + "NotObject"}};
+
+        Json::Value jvAsset;
+        if (value.as_object().contains(JS(issuer)))
+            jvAsset["issuer"] = value.at(JS(issuer)).as_string().c_str();
+        if (value.as_object().contains(JS(currency)))
+            jvAsset["currency"] = value.at(JS(currency)).as_string().c_str();
+        // same as rippled
+        try {
+            ripple::issueFromJson(jvAsset);
+        } catch (std::runtime_error const&) {
+            return Error{Status{ClioError::rpcMALFORMED_REQUEST}};
+        }
+
+        return MaybeError{};
+    }};
+
 }  // namespace rpc::validation

src/rpc/common/Validators.h

@@ -508,4 +508,11 @@ extern CustomValidator SubscribeStreamValidator;
  */
 extern CustomValidator SubscribeAccountsValidator;
 
+/**
+ * @brief Validates an asset (ripple::Issue).
+ *
+ * Used by amm_info.
+ */
+extern CustomValidator AMMAssetValidator;
+
 }  // namespace rpc::validation

src/rpc/common/impl/HandlerProvider.cpp

@@ -24,6 +24,7 @@
 #include "feed/SubscriptionManager.h"
 #include "rpc/Counters.h"
 #include "rpc/common/AnyHandler.h"
+#include "rpc/handlers/AMMInfo.h"
 #include "rpc/handlers/AccountChannels.h"
 #include "rpc/handlers/AccountCurrencies.h"
 #include "rpc/handlers/AccountInfo.h"
@@ -79,6 +80,7 @@ ProductionHandlerProvider::ProductionHandlerProvider(
           {"account_objects", {AccountObjectsHandler{backend}}},
           {"account_offers", {AccountOffersHandler{backend}}},
           {"account_tx", {AccountTxHandler{backend}}},
+          {"amm_info", {AMMInfoHandler{backend}}},
           {"book_changes", {BookChangesHandler{backend}}},
           {"book_offers", {BookOffersHandler{backend}}},
           {"deposit_authorized", {DepositAuthorizedHandler{backend}}},