[NOD-518] Implement getmempoolentry (#656)

mempool/mempool.go

@@ -459,7 +459,7 @@ func (mp *TxPool) removeTransactions(txs []*util.Tx) error {
 	for _, tx := range txs {
 		txID := tx.ID()
 
-		if _, exists := mp.fetchTransaction(txID); !exists {
+		if _, exists := mp.fetchTxDesc(txID); !exists {
 			continue
 		}
 
@@ -498,7 +498,7 @@ func (mp *TxPool) removeTransaction(tx *util.Tx, removeDependants bool, restoreI
 		}
 	}
 
-	if _, exists := mp.fetchTransaction(txID); !exists {
+	if _, exists := mp.fetchTxDesc(txID); !exists {
 		return nil
 	}
 
@@ -535,7 +535,7 @@ func (mp *TxPool) removeTransactionWithDiff(tx *util.Tx, diff *blockdag.UTXODiff
 		return errors.Errorf("could not mark transaction output as unspent: %s", err)
 	}
 
-	txDesc, _ := mp.fetchTransaction(txID)
+	txDesc, _ := mp.fetchTxDesc(txID)
 	if txDesc.depCount == 0 {
 		delete(mp.pool, *txID)
 	} else {
@@ -734,7 +734,7 @@ func (mp *TxPool) CheckSpend(op wire.Outpoint) *util.Tx {
 }
 
 // This function MUST be called with the mempool lock held (for reads).
-func (mp *TxPool) fetchTransaction(txID *daghash.TxID) (*TxDesc, bool) {
+func (mp *TxPool) fetchTxDesc(txID *daghash.TxID) (*TxDesc, bool) {
 	txDesc, exists := mp.pool[*txID]
 	if !exists {
 		txDesc, exists = mp.depends[*txID]
@@ -742,6 +742,22 @@ func (mp *TxPool) fetchTransaction(txID *daghash.TxID) (*TxDesc, bool) {
 	return txDesc, exists
 }
 
+// FetchTxDesc returns the requested TxDesc from the transaction pool.
+// This only fetches from the main transaction pool and does not include
+// orphans.
+//
+// This function is safe for concurrent access.
+func (mp *TxPool) FetchTxDesc(txID *daghash.TxID) (*TxDesc, error) {
+	mp.mtx.RLock()
+	defer mp.mtx.RUnlock()
+
+	if txDesc, exists := mp.fetchTxDesc(txID); exists {
+		return txDesc, nil
+	}
+
+	return nil, errors.Errorf("transaction is not in the pool")
+}
+
 // FetchTransaction returns the requested transaction from the transaction pool.
 // This only fetches from the main transaction pool and does not include
 // orphans.
@@ -752,7 +768,7 @@ func (mp *TxPool) FetchTransaction(txID *daghash.TxID) (*util.Tx, error) {
 	mp.mtx.RLock()
 	defer mp.mtx.RUnlock()
 
-	if txDesc, exists := mp.fetchTransaction(txID); exists {
+	if txDesc, exists := mp.fetchTxDesc(txID); exists {
 		return txDesc.Tx, nil
 	}
 

rpcmodel/rpc_results.go

@@ -171,23 +171,12 @@ type GetBlockTemplateResult struct {
 	RejectReasion string   `json:"rejectReason,omitempty"`
 }
 
-// GetMempoolEntryResult models the data returned from the getmempoolentry
+// GetMempoolEntryResult models the data returned from the getMempoolEntry
 // command.
 type GetMempoolEntryResult struct {
-	Size             int32    `json:"size"`
+	Fee   uint64      `json:"fee"`
-	Fee              float64  `json:"fee"`
+	Time  int64       `json:"time"`
-	ModifiedFee      float64  `json:"modifiedFee"`
+	RawTx TxRawResult `json:"rawTx"`
-	Time             int64    `json:"time"`
-	Height           uint64   `json:"height"`
-	StartingPriority float64  `json:"startingPriority"`
-	CurrentPriority  float64  `json:"currentPriority"`
-	DescendantCount  int64    `json:"descendantCount"`
-	DescendantSize   int64    `json:"descendantSize"`
-	DescendantFees   float64  `json:"descendantFees"`
-	AncestorCount    int64    `json:"ancestorCount"`
-	AncestorSize     int64    `json:"ancestorSize"`
-	AncestorFees     float64  `json:"ancestorFees"`
-	Depends          []string `json:"depends"`
 }
 
 // GetMempoolInfoResult models the data returned from the getmempoolinfo

server/rpc/handle_get_mempool_entry.go

@@ -0,0 +1,32 @@
+package rpc
+
+import (
+	"github.com/kaspanet/kaspad/rpcmodel"
+	"github.com/kaspanet/kaspad/util/daghash"
+)
+
+func handleGetMempoolEntry(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
+	c := cmd.(*rpcmodel.GetMempoolEntryCmd)
+	txID, err := daghash.NewTxIDFromStr(c.TxID)
+	if err != nil {
+		return nil, err
+	}
+
+	txDesc, err := s.cfg.TxMemPool.FetchTxDesc(txID)
+	if err != nil {
+		return nil, err
+	}
+
+	tx := txDesc.Tx
+	rawTx, err := createTxRawResult(s.cfg.DAGParams, tx.MsgTx(), tx.ID().String(),
+		nil, "", nil, true)
+	if err != nil {
+		return nil, err
+	}
+
+	return &rpcmodel.GetMempoolEntryResult{
+		Fee:   txDesc.Fee,
+		Time:  txDesc.Added.Unix(),
+		RawTx: *rawTx,
+	}, nil
+}

server/rpc/rpcserver.go

@@ -82,6 +82,7 @@ var rpcHandlersBeforeInit = map[string]commandHandler{
 	"getInfo":               handleGetInfo,
 	"getManualNodeInfo":     handleGetManualNodeInfo,
 	"getMempoolInfo":        handleGetMempoolInfo,
+	"getMempoolEntry":       handleGetMempoolEntry,
 	"getNetTotals":          handleGetNetTotals,
 	"getPeerInfo":           handleGetPeerInfo,
 	"getRawMempool":         handleGetRawMempool,

server/rpc/rpcserverhelp.go

@@ -227,7 +227,7 @@ var helpDescsEnUS = map[string]string{
 	"txRawResult-time":        "Transaction time in seconds since 1 Jan 1970 GMT",
 	"txRawResult-blockTime":   "Block time in seconds since the 1 Jan 1970 GMT",
 	"txRawResult-size":        "The size of the transaction in bytes",
-	"txRawResult-hash":        "The wtxid of the transaction",
+	"txRawResult-hash":        "The hash of the transaction",
 	"txRawResult-acceptedBy":  "The block in which the transaction got accepted in",
 
 	// GetBlockVerboseResult help.
@@ -390,6 +390,15 @@ var helpDescsEnUS = map[string]string{
 	// GetInfoCmd help.
 	"getInfo--synopsis": "Returns a JSON object containing various state info.",
 
+	// getMempoolEntry help.
+	"getMempoolEntry--synopsis": "Returns mempool data for given transaction",
+	"getMempoolEntry-txId":      "The transaction ID",
+
+	// getMempoolEntryResult help.
+	"getMempoolEntryResult-fee":   "Transaction fee in sompis",
+	"getMempoolEntryResult-time":  "Local time transaction entered pool in seconds since 1 Jan 1970 GMT",
+	"getMempoolEntryResult-rawTx": "The transaction as a JSON object",
+
 	// GetMempoolInfoCmd help.
 	"getMempoolInfo--synopsis": "Returns memory pool information",
 
@@ -603,6 +612,7 @@ var rpcResultTypes = map[string][]interface{}{
 	"getInfo":               {(*rpcmodel.InfoDAGResult)(nil)},
 	"getManualNodeInfo":     {(*string)(nil), (*rpcmodel.GetManualNodeInfoResult)(nil)},
 	"getMempoolInfo":        {(*rpcmodel.GetMempoolInfoResult)(nil)},
+	"getMempoolEntry":       {(*rpcmodel.GetMempoolEntryResult)(nil)},
 	"getNetTotals":          {(*rpcmodel.GetNetTotalsResult)(nil)},
 	"getPeerInfo":           {(*[]rpcmodel.GetPeerInfoResult)(nil)},
 	"getRawMempool":         {(*[]string)(nil), (*rpcmodel.GetRawMempoolVerboseResult)(nil)},