[#86] Add alphabet contract processor

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

pkg/innerring/processors/alphabet/processor.go

@@ -0,0 +1,86 @@
+package alphabet
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neofs-node/pkg/innerring/timers"
+	"github.com/nspcc-dev/neofs-node/pkg/morph/client"
+	"github.com/nspcc-dev/neofs-node/pkg/morph/event"
+	"github.com/panjf2000/ants/v2"
+	"github.com/pkg/errors"
+	"go.uber.org/zap"
+)
+
+type (
+	// Indexer is a callback interface for inner ring global state.
+	Indexer interface {
+		Index() int32
+	}
+
+	// Processor of events produced for alphabet contracts in sidechain.
+	Processor struct {
+		log               *zap.Logger
+		pool              *ants.Pool
+		alphabetContracts [7]util.Uint160
+		morphClient       *client.Client
+		irList            Indexer
+	}
+
+	// Params of the processor constructor.
+	Params struct {
+		Log               *zap.Logger
+		PoolSize          int
+		AlphabetContracts [7]util.Uint160
+		MorphClient       *client.Client
+		IRList            Indexer
+	}
+)
+
+// New creates neofs mainnet contract processor instance.
+func New(p *Params) (*Processor, error) {
+	switch {
+	case p.Log == nil:
+		return nil, errors.New("ir/alphabet: logger is not set")
+	case p.MorphClient == nil:
+		return nil, errors.New("ir/alphabet: neo:morph client is not set")
+	case p.IRList == nil:
+		return nil, errors.New("ir/alphabet: global state is not set")
+	}
+
+	p.Log.Debug("alphabet worker pool", zap.Int("size", p.PoolSize))
+
+	pool, err := ants.NewPool(p.PoolSize, ants.WithNonblocking(true))
+	if err != nil {
+		return nil, errors.Wrap(err, "ir/neofs: can't create worker pool")
+	}
+
+	return &Processor{
+		log:               p.Log,
+		pool:              pool,
+		alphabetContracts: p.AlphabetContracts,
+		morphClient:       p.MorphClient,
+		irList:            p.IRList,
+	}, nil
+}
+
+// ListenerParsers for the 'event.Listener' event producer.
+func (np *Processor) ListenerParsers() []event.ParserInfo {
+	return nil
+}
+
+// ListenerHandlers for the 'event.Listener' event producer.
+func (np *Processor) ListenerHandlers() []event.HandlerInfo {
+	return nil
+}
+
+// TimersHandlers for the 'Timers' event producer.
+func (np *Processor) TimersHandlers() []event.HandlerInfo {
+	var handlers []event.HandlerInfo
+
+	// new epoch handler
+	newEpoch := event.HandlerInfo{}
+	newEpoch.SetType(timers.AlphabetTimer)
+	newEpoch.SetHandler(np.handleGasEmission)
+	handlers = append(handlers, newEpoch)
+
+	return handlers
+}