ref: fcaa324e3c1eda45f6b3ea430fcd2c117e847ac1
dir: /common/herrors/error_locator.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
// limitations under the License.
// Package herrors contains common Hugo errors and error related utilities.
package herrors
import (
"io"
"io/ioutil"
"path/filepath"
"strings"
"github.com/gohugoio/hugo/common/text"
"github.com/spf13/afero"
)
// LineMatcher contains the elements used to match an error to a line
type LineMatcher struct {
Position text.Position
Error error
LineNumber int
Offset int
Line string
}
// LineMatcherFn is used to match a line with an error.
type LineMatcherFn func(m LineMatcher) bool
// SimpleLineMatcher simply matches by line number.
var SimpleLineMatcher = func(m LineMatcher) bool {
return m.Position.LineNumber == m.LineNumber
}
var _ text.Positioner = ErrorContext{}
// ErrorContext contains contextual information about an error. This will
// typically be the lines surrounding some problem in a file.
type ErrorContext struct {
// If a match will contain the matched line and up to 2 lines before and after.
// Will be empty if no match.
Lines []string
// The position of the error in the Lines above. 0 based.
LinesPos int
position text.Position
// The lexer to use for syntax highlighting.
// https://gohugo.io/content-management/syntax-highlighting/#list-of-chroma-highlighting-languages
ChromaLexer string
}
// Position returns the text position of this error.
func (e ErrorContext) Position() text.Position {
return e.position
}
var _ causer = (*ErrorWithFileContext)(nil)
// ErrorWithFileContext is an error with some additional file context related
// to that error.
type ErrorWithFileContext struct {
cause error
ErrorContext
}
func (e *ErrorWithFileContext) Error() string {
pos := e.Position()
if pos.IsValid() {
return pos.String() + ": " + e.cause.Error()
}
return e.cause.Error()
}
func (e *ErrorWithFileContext) Cause() error {
return e.cause
}
// WithFileContextForFile will try to add a file context with lines matching the given matcher.
// If no match could be found, the original error is returned with false as the second return value.
func WithFileContextForFile(e error, realFilename, filename string, fs afero.Fs, matcher LineMatcherFn) (error, bool) {
f, err := fs.Open(filename)
if err != nil {
return e, false
}
defer f.Close()
return WithFileContext(e, realFilename, f, matcher)
}
// WithFileContextForFile will try to add a file context with lines matching the given matcher.
// If no match could be found, the original error is returned with false as the second return value.
func WithFileContext(e error, realFilename string, r io.Reader, matcher LineMatcherFn) (error, bool) {
if e == nil {
panic("error missing")
}
le := UnwrapFileError(e)
if le == nil {
var ok bool
if le, ok = ToFileError("", e).(FileError); !ok {
return e, false
}
}
var errCtx ErrorContext
posle := le.Position()
if posle.Offset != -1 {
errCtx = locateError(r, le, func(m LineMatcher) bool {
if posle.Offset >= m.Offset && posle.Offset < m.Offset+len(m.Line) {
lno := posle.LineNumber - m.Position.LineNumber + m.LineNumber
m.Position = text.Position{LineNumber: lno}
}
return matcher(m)
})
} else {
errCtx = locateError(r, le, matcher)
}
pos := &errCtx.position
if pos.LineNumber == -1 {
return e, false
}
pos.Filename = realFilename
if le.Type() != "" {
errCtx.ChromaLexer = chromaLexerFromType(le.Type())
} else {
errCtx.ChromaLexer = chromaLexerFromFilename(realFilename)
}
return &ErrorWithFileContext{cause: e, ErrorContext: errCtx}, true
}
// UnwrapErrorWithFileContext tries to unwrap an ErrorWithFileContext from err.
// It returns nil if this is not possible.
func UnwrapErrorWithFileContext(err error) *ErrorWithFileContext {
for err != nil {
switch v := err.(type) {
case *ErrorWithFileContext:
return v
case causer:
err = v.Cause()
default:
return nil
}
}
return nil
}
func chromaLexerFromType(fileType string) string {
switch fileType {
case "html", "htm":
return "go-html-template"
}
return fileType
}
func extNoDelimiter(filename string) string {
return strings.TrimPrefix(filepath.Ext(filename), ".")
}
func chromaLexerFromFilename(filename string) string {
if strings.Contains(filename, "layouts") {
return "go-html-template"
}
ext := extNoDelimiter(filename)
return chromaLexerFromType(ext)
}
func locateErrorInString(src string, matcher LineMatcherFn) ErrorContext {
return locateError(strings.NewReader(src), &fileError{}, matcher)
}
func locateError(r io.Reader, le FileError, matches LineMatcherFn) ErrorContext {
if le == nil {
panic("must provide an error")
}
errCtx := ErrorContext{position: text.Position{LineNumber: -1, ColumnNumber: 1, Offset: -1}, LinesPos: -1}
b, err := ioutil.ReadAll(r)
if err != nil {
return errCtx
}
pos := &errCtx.position
lepos := le.Position()
lines := strings.Split(string(b), "\n")
if lepos.ColumnNumber >= 0 {
pos.ColumnNumber = lepos.ColumnNumber
}
lineNo := 0
posBytes := 0
for li, line := range lines {
lineNo = li + 1
m := LineMatcher{
Position: le.Position(),
Error: le,
LineNumber: lineNo,
Offset: posBytes,
Line: line,
}
if errCtx.LinesPos == -1 && matches(m) {
pos.LineNumber = lineNo
break
}
posBytes += len(line)
}
if pos.LineNumber != -1 {
low := pos.LineNumber - 3
if low < 0 {
low = 0
}
if pos.LineNumber > 2 {
errCtx.LinesPos = 2
} else {
errCtx.LinesPos = pos.LineNumber - 1
}
high := pos.LineNumber + 2
if high > len(lines) {
high = len(lines)
}
errCtx.Lines = lines[low:high]
}
return errCtx
}