add paginated query for loans by status

Author: keithsue

x/lending/keeper/loan.go

@@ -2,8 +2,10 @@ package keeper
 
 import (
 	sdkmath "cosmossdk.io/math"
+	"cosmossdk.io/store/prefix"
 	storetypes "cosmossdk.io/store/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/types/query"
 
 	"github.com/sideprotocol/side/x/lending/types"
 )
@@ -14,6 +16,8 @@ func (k Keeper) SetLoan(ctx sdk.Context, loan *types.Loan) {
 
 	bz := k.cdc.MustMarshal(loan)
 
+	k.SetLoanStatus(ctx, loan.VaultAddress, loan.Status)
+
 	store.Set(types.LoanKey(loan.VaultAddress), bz)
 }
 
@@ -24,6 +28,26 @@ func (k Keeper) SetLoanByAddress(ctx sdk.Context, loan *types.Loan) {
 	store.Set(types.LoanByAddressKey(loan.VaultAddress, loan.Borrower), []byte{})
 }
 
+// SetLoanStatus sets the status store of the given loan
+func (k Keeper) SetLoanStatus(ctx sdk.Context, id string, status types.LoanStatus) {
+	store := ctx.KVStore(k.storeKey)
+
+	if k.HasLoan(ctx, id) {
+		k.RemoveLoanStatus(ctx, id)
+	}
+
+	store.Set(types.LoanByStatusKey(status, id), []byte{})
+}
+
+// RemoveLoanStatus removes the status store of the given loan
+func (k Keeper) RemoveLoanStatus(ctx sdk.Context, id string) {
+	store := ctx.KVStore(k.storeKey)
+
+	loan := k.GetLoan(ctx, id)
+
+	store.Delete(types.LoanByStatusKey(loan.Status, id))
+}
+
 // HasLoan returns true if the given loan exists, false otherwise
 func (k Keeper) HasLoan(ctx sdk.Context, id string) bool {
 	store := ctx.KVStore(k.storeKey)
@@ -46,17 +70,58 @@ func (k Keeper) GetLoan(ctx sdk.Context, id string) *types.Loan {
 func (k Keeper) GetLoans(ctx sdk.Context, status types.LoanStatus) []*types.Loan {
 	var loans []*types.Loan
 
-	k.IterateLoans(ctx, func(loan *types.Loan) (stop bool) {
-		if loan.Status == status {
-			loans = append(loans, loan)
-		}
-
+	k.IterateLoansByStatus(ctx, status, func(loan *types.Loan) (stop bool) {
+		loans = append(loans, loan)
 		return false
 	})
 
 	return loans
 }
 
+// GetLoansByStatusWithPagination gets loans by the given status with pagination
+func (k Keeper) GetLoansByStatusWithPagination(ctx sdk.Context, status types.LoanStatus, pagination *query.PageRequest) ([]*types.Loan, *query.PageResponse, error) {
+	store := ctx.KVStore(k.storeKey)
+	loanStatusStore := prefix.NewStore(store, append(types.LoanByStatusKeyPrefix, sdk.Uint64ToBigEndian(uint64(status))...))
+
+	var loans []*types.Loan
+
+	pageRes, err := query.Paginate(loanStatusStore, pagination, func(key []byte, value []byte) error {
+		id := string(key)
+		loan := k.GetLoan(ctx, id)
+
+		loans = append(loans, loan)
+
+		return nil
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return loans, pageRes, nil
+}
+
+// GetLoansWithPagination gets loans with pagination
+func (k Keeper) GetLoansWithPagination(ctx sdk.Context, pagination *query.PageRequest) ([]*types.Loan, *query.PageResponse, error) {
+	store := ctx.KVStore(k.storeKey)
+	loanStore := prefix.NewStore(store, types.LoanKeyPrefix)
+
+	var loans []*types.Loan
+
+	pageRes, err := query.Paginate(loanStore, pagination, func(key []byte, value []byte) error {
+		var loan types.Loan
+		k.cdc.MustUnmarshal(value, &loan)
+
+		loans = append(loans, &loan)
+
+		return nil
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return loans, pageRes, nil
+}
+
 // GetPendingLoans gets the requested or authorized loans
 func (k Keeper) GetPendingLoans(ctx sdk.Context) []*types.Loan {
 	var loans []*types.Loan
@@ -118,6 +183,27 @@ func (k Keeper) IterateLoans(ctx sdk.Context, cb func(loan *types.Loan) (stop bo
 	}
 }
 
+// IterateLoansByStatus iterates through loans by the given status
+func (k Keeper) IterateLoansByStatus(ctx sdk.Context, status types.LoanStatus, cb func(loan *types.Loan) (stop bool)) {
+	store := ctx.KVStore(k.storeKey)
+
+	keyPrefix := append(types.LoanByStatusKeyPrefix, sdk.Uint64ToBigEndian(uint64(status))...)
+
+	iterator := storetypes.KVStorePrefixIterator(store, keyPrefix)
+	defer iterator.Close()
+
+	for ; iterator.Valid(); iterator.Next() {
+		key := iterator.Key()
+
+		id := string(key[len(keyPrefix):])
+		loan := k.GetLoan(ctx, id)
+
+		if cb(loan) {
+			break
+		}
+	}
+}
+
 // IterateLoansByAddress iterates through loans by the given address
 func (k Keeper) IterateLoansByAddress(ctx sdk.Context, address string, cb func(loan *types.Loan) (stop bool)) {
 	store := ctx.KVStore(k.storeKey)

x/lending/keeper/queries.go

@@ -10,6 +10,7 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2/schnorr"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/types/query"
 
 	"github.com/sideprotocol/side/x/lending/types"
 )
@@ -179,15 +180,21 @@ func (k Keeper) Loans(goCtx context.Context, req *types.QueryLoansRequest) (*typ
 
 	ctx := sdk.UnwrapSDKContext(goCtx)
 
+	var err error
 	var loans []*types.Loan
+	var pagination *query.PageResponse
 
 	if req.Status == types.LoanStatus_Unspecified {
-		loans = k.GetAllLoans(ctx)
+		loans, pagination, err = k.GetLoansWithPagination(ctx, req.Pagination)
 	} else {
-		loans = k.GetLoans(ctx, req.Status)
+		loans, pagination, err = k.GetLoansByStatusWithPagination(ctx, req.Status, req.Pagination)
+	}
+
+	if err != nil {
+		return nil, status.Error(codes.Internal, err.Error())
 	}
 
-	return &types.QueryLoansResponse{Loans: loans}, nil
+	return &types.QueryLoansResponse{Loans: loans, Pagination: pagination}, nil
 }
 
 // LoansByAddress implements types.QueryServer.

x/lending/types/keys.go

@@ -31,12 +31,13 @@ var (
 
 	PoolKeyPrefix            = []byte{0x10}
 	LoanKeyPrefix            = []byte{0x11}
-	LoanByAddressKeyPrefix   = []byte{0x12}
-	AuthorizationIdKeyPrefix = []byte{0x13}
-	DepositLogKeyPrefix      = []byte{0x14}
-	RepaymentKeyPrefix       = []byte{0x15}
-	DLCMetaKeyPrefix         = []byte{0x16}
-	RedemptionKeyPrefix      = []byte{0x17}
+	LoanByStatusKeyPrefix    = []byte{0x12}
+	LoanByAddressKeyPrefix   = []byte{0x13}
+	AuthorizationIdKeyPrefix = []byte{0x14}
+	DepositLogKeyPrefix      = []byte{0x15}
+	RepaymentKeyPrefix       = []byte{0x16}
+	DLCMetaKeyPrefix         = []byte{0x17}
+	RedemptionKeyPrefix      = []byte{0x18}
 
 	ReferrerKeyPrefix = []byte{0x20}
 )
@@ -49,6 +50,12 @@ func LoanKey(id string) []byte {
 	return append(LoanKeyPrefix, []byte(id)...)
 }
 
+func LoanByStatusKey(status LoanStatus, id string) []byte {
+	key := append(LoanByStatusKeyPrefix, sdk.Uint64ToBigEndian(uint64(status))...)
+
+	return append(key, []byte(id)...)
+}
+
 func LoanByAddressKey(id string, address string) []byte {
 	return append(append(LoanByAddressKeyPrefix, []byte(address)...), []byte(id)...)
 }