[WIP] Initial commit

vendor/github.com/cockroachdb/errors/join/join.go

@@ -0,0 +1,105 @@
+// Copyright 2019 The Cockroach Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License.
+
+package join
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/cockroachdb/errors/errbase"
+	"github.com/cockroachdb/redact"
+	"github.com/gogo/protobuf/proto"
+)
+
+// Join returns an error that wraps the given errors.
+// Any nil error values are discarded.
+// Join returns nil if errs contains no non-nil values.
+// The error formats as the concatenation of the strings obtained
+// by calling the Error method of each element of errs, with a newline
+// between each string.
+func Join(errs ...error) error {
+	n := 0
+	for _, err := range errs {
+		if err != nil {
+			n++
+		}
+	}
+	if n == 0 {
+		return nil
+	}
+	e := &joinError{
+		errs: make([]error, 0, n),
+	}
+	for _, err := range errs {
+		if err != nil {
+			e.errs = append(e.errs, err)
+		}
+	}
+	return e
+}
+
+type joinError struct {
+	errs []error
+}
+
+var _ error = (*joinError)(nil)
+var _ fmt.Formatter = (*joinError)(nil)
+var _ errbase.SafeFormatter = (*joinError)(nil)
+
+func (e *joinError) Error() string {
+	return redact.Sprint(e).StripMarkers()
+}
+
+func (e *joinError) Unwrap() []error {
+	return e.errs
+}
+
+func (e *joinError) SafeFormatError(p errbase.Printer) error {
+	for i, err := range e.errs {
+		if i > 0 {
+			p.Print("\n")
+		}
+		p.Print(err)
+	}
+	return nil
+}
+
+func (e *joinError) Format(s fmt.State, verb rune) {
+	errbase.FormatError(e, s, verb)
+}
+
+func init() {
+	errbase.RegisterMultiCauseEncoder(
+		errbase.GetTypeKey(&joinError{}),
+		func(
+			ctx context.Context,
+			err error,
+		) (msg string, safeDetails []string, payload proto.Message) {
+			return "", nil, nil
+		},
+	)
+	errbase.RegisterMultiCauseDecoder(
+		errbase.GetTypeKey(&joinError{}),
+		func(
+			ctx context.Context,
+			causes []error,
+			msgPrefix string,
+			safeDetails []string,
+			payload proto.Message,
+		) error {
+			return Join(causes...)
+		},
+	)
+}