mempool+rpcserver: add interface TxMempool

This commit adds a new interface `TxMempool` which defines how other subsystems interact with `TxPool`.
btcsuite · Roasbeef · Jan 16, 2024 · Jan 4, 2024 · Nov 3, 2023 · Nov 3, 2023
commit 4842b23247096e08327e8ff1447ee89e1617cf9d
diff --git a/mempool/interface.go b/mempool/interface.go
@@ -0,0 +1,71 @@
+package mempool
+
+import (
+	"time"
+
+	"github.com/btcsuite/btcd/btcjson"
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcd/wire"
+)
+
+// TxMempool defines an interface that's used by other subsystems to interact
+// with the mempool.
+type TxMempool interface {
+	// LastUpdated returns the last time a transaction was added to or
+	// removed from the source pool.
+	LastUpdated() time.Time
+
+	// TxDescs returns a slice of descriptors for all the transactions in
+	// the pool.
+	TxDescs() []*TxDesc
+
+	// RawMempoolVerbose returns all the entries in the mempool as a fully
+	// populated btcjson result.
+	RawMempoolVerbose() map[string]*btcjson.GetRawMempoolVerboseResult
+
+	// Count returns the number of transactions in the main pool. It does
+	// not include the orphan pool.
+	Count() int
+
+	// FetchTransaction returns the requested transaction from the
+	// transaction pool. This only fetches from the main transaction pool
+	// and does not include orphans.
+	FetchTransaction(txHash *chainhash.Hash) (*btcutil.Tx, error)
+
+	// HaveTransaction returns whether or not the passed transaction
+	// already exists in the main pool or in the orphan pool.
+	HaveTransaction(hash *chainhash.Hash) bool
+
+	// ProcessTransaction is the main workhorse for handling insertion of
+	// new free-standing transactions into the memory pool. It includes
+	// functionality such as rejecting duplicate transactions, ensuring
+	// transactions follow all rules, orphan transaction handling, and
+	// insertion into the memory pool.
+	//
+	// It returns a slice of transactions added to the mempool. When the
+	// error is nil, the list will include the passed transaction itself
+	// along with any additional orphan transactions that were added as a
+	// result of the passed one being accepted.
+	ProcessTransaction(tx *btcutil.Tx, allowOrphan,
+		rateLimit bool, tag Tag) ([]*TxDesc, error)
+
+	// RemoveTransaction removes the passed transaction from the mempool.
+	// When the removeRedeemers flag is set, any transactions that redeem
+	// outputs from the removed transaction will also be removed
+	// recursively from the mempool, as they would otherwise become
+	// orphans.
+	RemoveTransaction(tx *btcutil.Tx, removeRedeemers bool)
+
+	// CheckMempoolAcceptance behaves similarly to bitcoind's
+	// `testmempoolaccept` RPC method. It will perform a series of checks
+	// to decide whether this transaction can be accepted to the mempool.
+	// If not, the specific error is returned and the caller needs to take
+	// actions based on it.
+	CheckMempoolAcceptance(tx *btcutil.Tx) (*MempoolAcceptResult, error)
+
+	// CheckSpend checks whether the passed outpoint is already spent by
+	// a transaction in the mempool. If that's the case the spending
+	// transaction will be returned, if not nil will be returned.
+	CheckSpend(op wire.OutPoint) *btcutil.Tx
+}
diff --git a/mempool/mempool.go b/mempool/mempool.go
@@ -196,6 +196,9 @@ type TxPool struct {
 // Ensure the TxPool type implements the mining.TxSource interface.
 var _ mining.TxSource = (*TxPool)(nil)
 
+// Ensure the TxPool type implements the TxMemPool interface.
+var _ TxMempool = (*TxPool)(nil)
+
 // removeOrphan is the internal function which implements the public
 // RemoveOrphan.  See the comment for RemoveOrphan for more details.
 //

diff --git a/rpcserver.go b/rpcserver.go
@@ -4633,7 +4633,7 @@ type rpcserverConfig struct {
 	DB          database.DB
 
 	// TxMemPool defines the transaction memory pool to interact with.
-	TxMemPool *mempool.TxPool
+	TxMemPool mempool.TxMempool
 
 	// These fields allow the RPC server to interface with mining.
 	//