Caption support (#2462)

Co-authored-by: WithoutPants <53250216+WithoutPants@users.noreply.github.com>

vendor/github.com/asticode/go-astikit/errors.go

@@ -0,0 +1,71 @@
+package astikit
+
+import (
+	"errors"
+	"strings"
+	"sync"
+)
+
+// Errors is an error containing multiple errors
+type Errors struct {
+	m *sync.Mutex // Locks p
+	p []error
+}
+
+// NewErrors creates new errors
+func NewErrors(errs ...error) *Errors {
+	return &Errors{
+		m: &sync.Mutex{},
+		p: errs,
+	}
+}
+
+// Add adds a new error
+func (errs *Errors) Add(err error) {
+	if err == nil {
+		return
+	}
+	errs.m.Lock()
+	defer errs.m.Unlock()
+	errs.p = append(errs.p, err)
+}
+
+// IsNil checks whether the error is nil
+func (errs *Errors) IsNil() bool {
+	errs.m.Lock()
+	defer errs.m.Unlock()
+	return len(errs.p) == 0
+}
+
+// Loop loops through the errors
+func (errs *Errors) Loop(fn func(idx int, err error) bool) {
+	errs.m.Lock()
+	defer errs.m.Unlock()
+	for idx, err := range errs.p {
+		if stop := fn(idx, err); stop {
+			return
+		}
+	}
+}
+
+// Error implements the error interface
+func (errs *Errors) Error() string {
+	errs.m.Lock()
+	defer errs.m.Unlock()
+	var ss []string
+	for _, err := range errs.p {
+		ss = append(ss, err.Error())
+	}
+	return strings.Join(ss, " && ")
+}
+
+// ErrorCause returns the cause of an error
+func ErrorCause(err error) error {
+	for {
+		if u := errors.Unwrap(err); u != nil {
+			err = u
+			continue
+		}
+		return err
+	}
+}