Transaction filter (#5)

* tx filter

* change TxFilter type

* basic filters

* lint

* fixup

* Missing lock acquisition

* fixup

* lint

* fixup

* add filter priority order

* lint

* fixup

* save: use insertion queue

* filter-as-an-option

* fmt

* fixup

* pointer filter

* fixup

* fieldalignment

serve/filters/filter/tx.go

@@ -0,0 +1,107 @@
+package filter
+
+import (
+	"github.com/gnolang/gno/tm2/pkg/bft/types"
+)
+
+type Options struct {
+	GasUsed   struct{ Min, Max *int64 }
+	GasWanted struct{ Min, Max *int64 }
+	GasLimit  struct{ Min, Max *int64 }
+}
+
+// TxFilter holds a slice of transaction results.
+// It provides methods to manipulate and query the transactions.
+type TxFilter struct {
+	opts Options
+	*baseFilter
+	txs []*types.TxResult
+}
+
+// NewTxFilter creates a new TxFilter object.
+func NewTxFilter(opts Options) *TxFilter {
+	return &TxFilter{
+		baseFilter: newBaseFilter(TxFilterType),
+		txs:        make([]*types.TxResult, 0),
+		opts:       opts,
+	}
+}
+
+// GetHashes iterates over all transactions in the filter and returns their hashes.
+func (tf *TxFilter) GetHashes() [][]byte {
+	tf.Lock()
+	defer tf.Unlock()
+
+	hashes := make([][]byte, 0, len(tf.txs))
+
+	for _, txr := range tf.txs {
+		var hash []byte
+
+		if txr != nil && txr.Tx != nil {
+			hash = txr.Tx.Hash()
+		}
+
+		hashes = append(hashes, hash)
+	}
+
+	return hashes
+}
+
+func (tf *TxFilter) UpdateWithTx(tx *types.TxResult) {
+	tf.Lock()
+	defer tf.Unlock()
+
+	tf.txs = append(tf.txs, tx)
+}
+
+// Apply applies all added conditions to the transactions in the filter.
+//
+// It returns a slice of `TxResult` that satisfy all the conditions. If no conditions are set,
+// it returns all transactions in the filter. Also, if the filter value is invalid filter will not
+// be applied.
+func (tf *TxFilter) Apply() []*types.TxResult {
+	tf.Lock()
+	defer tf.Unlock()
+
+	return checkOpts(tf.txs, tf.opts)
+}
+
+func checkOpts(txs []*types.TxResult, opts Options) []*types.TxResult {
+	filtered := make([]*types.TxResult, 0, len(txs))
+
+	for _, tx := range txs {
+		if checkFilterCondition(tx, opts) {
+			filtered = append(filtered, tx)
+		}
+	}
+
+	return filtered
+}
+
+func checkFilterCondition(tx *types.TxResult, opts Options) bool {
+	if opts.GasLimit.Max != nil && tx.Response.GasUsed > *opts.GasLimit.Max {
+		return false
+	}
+
+	if opts.GasLimit.Min != nil && tx.Response.GasUsed < *opts.GasLimit.Min {
+		return false
+	}
+
+	if opts.GasUsed.Max != nil && tx.Response.GasUsed > *opts.GasUsed.Max {
+		return false
+	}
+
+	if opts.GasUsed.Min != nil && tx.Response.GasUsed < *opts.GasUsed.Min {
+		return false
+	}
+
+	if opts.GasWanted.Max != nil && tx.Response.GasWanted > *opts.GasWanted.Max {
+		return false
+	}
+
+	if opts.GasWanted.Min != nil && tx.Response.GasWanted < *opts.GasWanted.Min {
+		return false
+	}
+
+	return true
+}