HasFilter to check whether some filter was loaded by the poller (#10469)

Co-authored-by: Domino Valdano <[email protected]>

core/chains/evm/logpoller/disabled.go

@@ -37,6 +37,8 @@ func (disabled) RegisterFilter(filter Filter, qopts ...pg.QOpt) error { return E
 
 func (disabled) UnregisterFilter(name string, qopts ...pg.QOpt) error { return ErrDisabled }
 
+func (disabled) HasFilter(name string) bool { return false }
+
 func (disabled) LatestBlock(qopts ...pg.QOpt) (int64, error) { return -1, ErrDisabled }
 
 func (disabled) GetBlocksRange(ctx context.Context, numbers []uint64, qopts ...pg.QOpt) ([]LogPollerBlock, error) {

core/chains/evm/logpoller/log_poller.go

@@ -36,6 +36,7 @@ type LogPoller interface {
 	ReplayAsync(fromBlock int64)
 	RegisterFilter(filter Filter, qopts ...pg.QOpt) error
 	UnregisterFilter(name string, qopts ...pg.QOpt) error
+	HasFilter(name string) bool
 	LatestBlock(qopts ...pg.QOpt) (int64, error)
 	GetBlocksRange(ctx context.Context, numbers []uint64, qopts ...pg.QOpt) ([]LogPollerBlock, error)
 
@@ -258,6 +259,15 @@ func (lp *logPoller) UnregisterFilter(name string, qopts ...pg.QOpt) error {
 	return nil
 }
 
+// HasFilter returns true if the log poller has an active filter with the given name.
+func (lp *logPoller) HasFilter(name string) bool {
+	lp.filterMu.RLock()
+	defer lp.filterMu.RUnlock()
+
+	_, ok := lp.filters[name]
+	return ok
+}
+
 func (lp *logPoller) Filter(from, to *big.Int, bh *common.Hash) ethereum.FilterQuery {
 	lp.filterMu.Lock()
 	defer lp.filterMu.Unlock()

core/chains/evm/logpoller/log_poller_test.go

@@ -760,6 +760,13 @@ func TestLogPoller_LoadFilters(t *testing.T) {
 	require.True(t, ok)
 	assert.True(t, filter.Contains(&filter3))
 	assert.True(t, filter3.Contains(&filter))
+
+	t.Run("HasFilter", func(t *testing.T) {
+		assert.True(t, th.LogPoller.HasFilter("first Filter"))
+		assert.True(t, th.LogPoller.HasFilter("second Filter"))
+		assert.True(t, th.LogPoller.HasFilter("third Filter"))
+		assert.False(t, th.LogPoller.HasFilter("fourth Filter"))
+	})
 }
 
 func TestLogPoller_GetBlocks_Range(t *testing.T) {