Copy certifiers from light-client

certifiers/errors/errors.go

@@ -0,0 +1,86 @@
+package errors
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+)
+
+var (
+	errValidatorsChanged = fmt.Errorf("Validators differ between header and certifier")
+	errCommitNotFound    = fmt.Errorf("Commit not found by provider")
+	errTooMuchChange     = fmt.Errorf("Validators change too much to safely update")
+	errPastTime          = fmt.Errorf("Update older than certifier height")
+	errNoPathFound       = fmt.Errorf("Cannot find a path of validators")
+)
+
+// IsCommitNotFoundErr checks whether an error is due to missing data
+func IsCommitNotFoundErr(err error) bool {
+	return err != nil && (errors.Cause(err) == errCommitNotFound)
+}
+
+func ErrCommitNotFound() error {
+	return errors.WithStack(errCommitNotFound)
+}
+
+// IsValidatorsChangedErr checks whether an error is due
+// to a differing validator set
+func IsValidatorsChangedErr(err error) bool {
+	return err != nil && (errors.Cause(err) == errValidatorsChanged)
+}
+
+func ErrValidatorsChanged() error {
+	return errors.WithStack(errValidatorsChanged)
+}
+
+// IsTooMuchChangeErr checks whether an error is due to too much change
+// between these validators sets
+func IsTooMuchChangeErr(err error) bool {
+	return err != nil && (errors.Cause(err) == errTooMuchChange)
+}
+
+func ErrTooMuchChange() error {
+	return errors.WithStack(errTooMuchChange)
+}
+
+func IsPastTimeErr(err error) bool {
+	return err != nil && (errors.Cause(err) == errPastTime)
+}
+
+func ErrPastTime() error {
+	return errors.WithStack(errPastTime)
+}
+
+// IsNoPathFoundErr checks whether an error is due to no path of
+// validators in provider from where we are to where we want to be
+func IsNoPathFoundErr(err error) bool {
+	return err != nil && (errors.Cause(err) == errNoPathFound)
+}
+
+func ErrNoPathFound() error {
+	return errors.WithStack(errNoPathFound)
+}
+
+//--------------------------------------------
+
+type errHeightMismatch struct {
+	h1, h2 int
+}
+
+func (e errHeightMismatch) Error() string {
+	return fmt.Sprintf("Blocks don't match - %d vs %d", e.h1, e.h2)
+}
+
+// IsHeightMismatchErr checks whether an error is due to data from different blocks
+func IsHeightMismatchErr(err error) bool {
+	if err == nil {
+		return false
+	}
+	_, ok := errors.Cause(err).(errHeightMismatch)
+	return ok
+}
+
+// ErrHeightMismatch returns an mismatch error with stack-trace
+func ErrHeightMismatch(h1, h2 int) error {
+	return errors.WithStack(errHeightMismatch{h1, h2})
+}

certifiers/errors/errors_test.go

@@ -0,0 +1,18 @@
+package errors
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestErrorHeight(t *testing.T) {
+	e1 := ErrHeightMismatch(2, 3)
+	e1.Error()
+	assert.True(t, IsHeightMismatchErr(e1))
+
+	e2 := errors.New("foobar")
+	assert.False(t, IsHeightMismatchErr(e2))
+	assert.False(t, IsHeightMismatchErr(nil))
+}