hugo/common/herrors/file_error.go

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// Copyright 2018 The Hugo Authors. All rights reserved.
//
// 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 herrors
import (
"encoding/json"
"github.com/gohugoio/hugo/common/text"
"github.com/pkg/errors"
)
var (
_ causer = (*fileError)(nil)
)
// FileError represents an error when handling a file: Parsing a config file,
// execute a template etc.
type FileError interface {
error
text.Positioner
// A string identifying the type of file, e.g. JSON, TOML, markdown etc.
Type() string
}
var _ FileError = (*fileError)(nil)
type fileError struct {
position text.Position
fileType string
cause error
}
// Position returns the text position of this error.
func (e fileError) Position() text.Position {
return e.position
}
func (e *fileError) Type() string {
return e.fileType
}
func (e *fileError) Error() string {
if e.cause == nil {
return ""
}
return e.cause.Error()
}
func (f *fileError) Cause() error {
return f.cause
}
// NewFileError creates a new FileError.
func NewFileError(fileType string, offset, lineNumber, columnNumber int, err error) FileError {
pos := text.Position{Offset: offset, LineNumber: lineNumber, ColumnNumber: columnNumber}
return &fileError{cause: err, fileType: fileType, position: pos}
}
// UnwrapFileError tries to unwrap a FileError from err.
// It returns nil if this is not possible.
func UnwrapFileError(err error) FileError {
for err != nil {
switch v := err.(type) {
case FileError:
return v
case causer:
err = v.Cause()
default:
return nil
}
}
return nil
}
// ToFileErrorWithOffset will return a new FileError with a line number
// with the given offset from the original.
func ToFileErrorWithOffset(fe FileError, offset int) FileError {
pos := fe.Position()
return ToFileErrorWithLineNumber(fe, pos.LineNumber+offset)
}
// ToFileErrorWithOffset will return a new FileError with the given line number.
func ToFileErrorWithLineNumber(fe FileError, lineNumber int) FileError {
pos := fe.Position()
pos.LineNumber = lineNumber
return &fileError{cause: fe, fileType: fe.Type(), position: pos}
}
// ToFileError will convert the given error to an error supporting
// the FileError interface.
func ToFileError(fileType string, err error) FileError {
for _, handle := range lineNumberExtractors {
lno, col := handle(err)
offset, typ := extractOffsetAndType(err)
if fileType == "" {
fileType = typ
}
if lno > 0 || offset != -1 {
return NewFileError(fileType, offset, lno, col, err)
}
}
// Fall back to the pointing to line number 1.
return NewFileError(fileType, -1, 1, 1, err)
}
func extractOffsetAndType(e error) (int, string) {
e = errors.Cause(e)
switch v := e.(type) {
case *json.UnmarshalTypeError:
return int(v.Offset), "json"
case *json.SyntaxError:
return int(v.Offset), "json"
default:
return -1, ""
}
}