isolate V2 contract interaction API into its own package

Author: jwasinger

accounts/abi/bind/v2/lib.go

@@ -0,0 +1,135 @@
+package v2
+
+import (
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/ethereum/go-ethereum/accounts/abi/bind"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/event"
+)
+
+func FilterLogs[T any](instance bind.ContractInstance, opts *bind.FilterOpts, eventID common.Hash, unpack func(*types.Log) (*T, error), topics ...[]any) (*EventIterator[T], error) {
+	backend := instance.Backend()
+	c := bind.NewBoundContract(instance.Address(), abi.ABI{}, backend, backend, backend)
+	logs, sub, err := c.FilterLogs(opts, eventID.String(), topics...)
+	if err != nil {
+		return nil, err
+	}
+	return &EventIterator[T]{unpack: unpack, logs: logs, sub: sub}, nil
+}
+
+func WatchLogs[T any](instance bind.ContractInstance, opts *bind.WatchOpts, eventID common.Hash, unpack func(*types.Log) (*T, error), sink chan<- *T, topics ...[]any) (event.Subscription, error) {
+	backend := instance.Backend()
+	c := bind.NewBoundContract(instance.Address(), abi.ABI{}, backend, backend, backend)
+	logs, sub, err := c.WatchLogs(opts, eventID.String(), topics...)
+	if err != nil {
+		return nil, err
+	}
+	return event.NewSubscription(func(quit <-chan struct{}) error {
+		defer sub.Unsubscribe()
+		for {
+			select {
+			case log := <-logs:
+				// New log arrived, parse the event and forward to the user
+				ev, err := unpack(&log)
+				if err != nil {
+					return err
+				}
+
+				select {
+				case sink <- ev:
+				case err := <-sub.Err():
+					return err
+				case <-quit:
+					return nil
+				}
+			case err := <-sub.Err():
+				return err
+			case <-quit:
+				return nil
+			}
+		}
+	}), nil
+}
+
+// EventIterator is returned from FilterLogs and is used to iterate over the raw logs and unpacked data for events.
+type EventIterator[T any] struct {
+	Event *T // Event containing the contract specifics and raw log
+
+	unpack func(*types.Log) (*T, error) // Unpack function for the event
+
+	logs chan types.Log        // Log channel receiving the found contract events
+	sub  ethereum.Subscription // Subscription for errors, completion and termination
+	done bool                  // Whether the subscription completed delivering logs
+	fail error                 // Occurred error to stop iteration
+}
+
+// Next advances the iterator to the subsequent event, returning whether there
+// are any more events found. In case of a retrieval or parsing error, false is
+// returned and Error() can be queried for the exact failure.
+func (it *EventIterator[T]) Next() bool {
+	// If the iterator failed, stop iterating
+	if it.fail != nil {
+		return false
+	}
+	// If the iterator completed, deliver directly whatever's available
+	if it.done {
+		select {
+		case log := <-it.logs:
+			res, err := it.unpack(&log)
+			if err != nil {
+				it.fail = err
+				return false
+			}
+			it.Event = res
+			return true
+
+		default:
+			return false
+		}
+	}
+	// Iterator still in progress, wait for either a data or an error event
+	select {
+	case log := <-it.logs:
+		res, err := it.unpack(&log)
+		if err != nil {
+			it.fail = err
+			return false
+		}
+		it.Event = res
+		return true
+
+	case err := <-it.sub.Err():
+		it.done = true
+		it.fail = err
+		return it.Next()
+	}
+}
+
+// Error returns any retrieval or parsing error occurred during filtering.
+func (it *EventIterator[T]) Error() error {
+	return it.fail
+}
+
+// Close terminates the iteration process, releasing any pending underlying
+// resources.
+func (it *EventIterator[T]) Close() error {
+	it.sub.Unsubscribe()
+	return nil
+}
+
+func Transact(instance bind.ContractInstance, opts *bind.TransactOpts, input []byte) (*types.Transaction, error) {
+	var (
+		addr    = instance.Address()
+		backend = instance.Backend()
+	)
+	c := bind.NewBoundContract(addr, abi.ABI{}, backend, backend, backend)
+	return c.RawTransact(opts, input)
+}
+
+func Transfer(instance bind.ContractInstance, opts *bind.TransactOpts) (*types.Transaction, error) {
+	backend := instance.Backend()
+	c := bind.NewBoundContract(instance.Address(), abi.ABI{}, backend, backend, backend)
+	return c.Transfer(opts)
+}