hugo/common/herrors/file_error.go
Bjørn Erik Pedersen f669ef6bec
herrors: Improve handling of JSON errors
`*json.UnmarshalTypeError` and `*json.SyntaxError` has a byte `Offset`, so use that.

This commit also reworks/simplifies the errror line matching logic. This also makes the file reading unbuffered, but that should be fine in this error case.

See #5324
2018-10-23 14:35:43 +02:00

144 lines
3.4 KiB
Go

// 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
// limitatio ns under the License.
package herrors
import (
"encoding/json"
"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
// Offset gets the error location offset in bytes, starting at 0.
// It will return -1 if not provided.
Offset() int
// LineNumber gets the error location, starting at line 1.
LineNumber() int
// Column number gets the column location, starting at 1.
ColumnNumber() int
// A string identifying the type of file, e.g. JSON, TOML, markdown etc.
Type() string
}
var _ FileError = (*fileError)(nil)
type fileError struct {
offset int
lineNumber int
columnNumber int
fileType string
cause error
}
type fileErrorWithLineOffset struct {
FileError
offset int
}
func (e *fileErrorWithLineOffset) LineNumber() int {
return e.FileError.LineNumber() + e.offset
}
func (e *fileError) LineNumber() int {
return e.lineNumber
}
func (e *fileError) Offset() int {
return e.offset
}
func (e *fileError) ColumnNumber() int {
return e.columnNumber
}
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 {
return &fileError{cause: err, fileType: fileType, offset: offset, lineNumber: lineNumber, columnNumber: columnNumber}
}
// 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 {
return &fileErrorWithLineOffset{FileError: fe, offset: offset}
}
// 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, ""
}
}